r LOAI

Guide to Gammon Tidal IVlarsh

Invertebrates of the Northeastern

Gulf of IVlexico

by

Richard W. Heard UniversityofSouth Alabama, Mobile, AL 36688 and CiulfCoast Research Laboratory, Ocean Springs, MS39564"

Illustrations by rimed:tul""'"' ' "=tel' ""'Oo' OR" Iindu B. I utz URt,i',"::.:l'.'.;,',-'-.,":,':::.';..-'",r;»:.",'> i;."

Thisv,ork isa resultofreseaich sponsored inpart by the U.S. Department ofCommerce, NOAA, Office ofSea Grant, underGrani Nos. 04 8 Mol 92,NA79AA D 00049,and NA81AA D 00050, bythe Mississippi Alabama SeaGrant Consortium, byche University ofSouth Alabama, bythe Gulf Coast Research Laboratory, andby the Marine EnvironmentalSciences Consortium. TheU.S. Government isauthorized toproduce anddistribute reprints forgovern- inentalpurposes notwithstanding anycopyright notation that may appear hereon.

*Preseitt address. This Handbook is dedicated to

WILL HOLMES friend and gentleman

Copyright! 1982by Mississippi hlabama SeaGrant Consortium and R. W. Heard

All rightsreserved. No part of thisbook may be reproduced in any manner without permissionfrom the author.

Printed by Reinbold Lithographing& PrintingCo., BooneviBe,MS 38829. CONTENTS

27 PREFACE FamilyMysidae OrderTanaidacea Tanaids!,...... 28 INTRODUCTION FamilyParatanaidae...... , .. 29 30 SALTMARSH INVERTEBRATES ., FamilyApseudidae,...... ,... Order Cumacea 30 PhylumCnidaria =Coelenterata!...... , . FamilyNannasticidae...... ,... 31 32 Class Anthozoa OrderIsopoda Isopods! 32 Fainily Edwardsiidae. FamilyAnthuridae Anthurids!... 3 3 32 PhylumAnnelida Annelids! F~ily Sphaeromidae Sphaeromids! ClassOligochaeta Oligochaetes!...... Family Munnidae ...,,...... 34 34 ClassHirudinea Leeches! FamilyAsellidae...... 35 ClassPolychaeta Polychaetes!...,.... FamilyBopyridae FamilyNereidae Nereids!...... OrderAmphipoda Amphipods!...., 36 FamilyPilargiidae Pilargiids! Fanuly Hyahdae 36 FamilyOrbiniidae Orbiniids!...... FamilyGamrnaridae...... ,... 36 FamilyCapitellidae Capitellids!..... Family Melitidae...... 37 FamilyAmpharetidae Ampharetids! . 4689 Family69Aoridae 38 39 FamilySpionidae Spionids!...., .. Family Corophiidae...... FamilySabellidae Sabellids!...... Family Hyalellidae 40 FamilySerpulidae Serpulids!...... Fainily Talitr idae 40 PhylumMollusca Mollusks! . 10 SuperorderEucarida . 44 ClassGastropoda Gastropods!...,.... 10 Order Decapoda 44 44 Family Neritidae Nerites!... 10 Suborder Dendrobranchiata...... 44 Fainily Hydrobiidae Hydrobiids!.... 11 Infraorder Penaeidea...... 44 Faniily Assiinineidae....., . IS F amilyPenaeidae 46 Family Potarnidae 16 SuborderPleocyernata..., 46 FamilyLittorinidae Periwinkles!.... 17 lnfraorder Caridea,...,...... Family Melongenidae Whelks!,..., .. 18 FamilyPalaemonidae Fainily Pyramidellidae Pyram Shells!.. 18 PalaeinonidShriinps! 46 FainilyMelampidae Melarnpid Snails!.. 19 lnfraorder Anomura...... 46 ClassBivalvia =Pelecypoda! Bivalves!... 20 FamilyDiogemdae Family Corbiculidae MarshClams!.... 21 DiogeiiidHermit Crabs! 48 48 Family Mactridae .. 21 InfraorderBrachyura Crabs!.... Family Mytilidae Mussels!...... , .. 22 Famdy Portunidae 48 Fainily Dresseuidae . 22 SwimmingCrabs! Family Xanthldae Mud Crabs! 50 Family Cyrenoididae 23 54 Family Solecurtidae 24 Family Grapsidae,...... FamilyOcypodidae...... ,, 56 Family Ostreidae. 24 Phyluin Arthropoda. 25 61 SubphylumCrustacea, . 26 ACKNOWLEDGMENTS 26 Class Cirrepedia.. BIBLIOGRAPHY, 62 Order Thoracica . 26 Suborder Balanornorpha...... 26 TAXONOMIC KEYS . 66 27 Class Malacost raca GLOSSARY, 78 SuperorderPeracarida...... 27 Order Mysidacea .. 27 INDEX . PRE I'ACE part of the estuarine"nursery grounds" for many fishes and invertebrates. Since the realization of the ecological and eco- Salt rnarshesare formed along the shoresof nomic importanceof salt marshes,millions of dollars coastalplains in thetemperate and tropical zones of in researchfunds have been allocated for the study of the world wherever wave action is slowed enough to these valuableand productive wetlands,Very little allowgrasses to becomeestablished. They are found information, however, has been compiled for the in the intertidal zone in shallow water, in the lee of identification of marine and estuarine salt marsh in- sea islands,along borders of bays and inlets, and vertebrates. Ursin 972! and Olmstead and Fell zlongtidal streams, bayous, and the mouths of rivers. 974! havepublished handbooks or guidesto salt In the United States, an almost continuous band of marshorganisms, but both theseguides are designed saltmarshes fringes the Atlanticand Gulf coasts.The for the temperatetidal marshesof the Atlantic coast. predominantgrass in Atlantic coastalmarshes is The only popular accountof salt marshinvertebrates smoothcordgrass, Spartina alterniflora. Tides along for our regionis a guideby I-'otheringhamand Brun- the Atlantic coast occur regularly twice a day and enrneister975!* to the commoninvertebrates of the haveamplitudes of 4 to 8 feet ,3 to 2.6 meters!. northwesternGulf Coast.Although their treatmentis Conditions are different in the northern Gulf of Mex- interesting,it is generaland thereforelimited in its ico wheretides in most regionsoccur at irregularin- treatment of tidal marsh invertebrates. Teal 962!, tervals znd are much lower in amplitude than along in his paperon Georgiasalt marshes,wzs the first to the Atlantic coast. Tides in the Gulf are usually no givean extensive list of saltmarsh invertebrates. The higherthan 1,5 feet ,5 meters!.Strong southerly mostcomprehensive faunal study of the saltmzrshes winds can "blow in the tide" during a normal low of the northern Gulf was that of Subrahmanyamet al tide, and strong northerly winds can "blow out the 976!. They listed over 50 speciesof marinemacro- tide" duringa normalhigh tide. The weaktidal ampli- invertebratesfrom Juncus-Spartinatidal marshesand tudes restrict the intertidal zone and may be a factor adjacenttidal marshcreeks at St.Marks, Florida. limiting the populationof smoothcordgr ass. The I feel that the necessityfor this handbookis dominantgrass in Gulf coastalmarshes is needlegrzss supportedby the manyrequests for identificationof or black rush,Juncus roemerianus. The areacovered salt marshspecies that I havereceived during the past by theGulf tidal marshes is reported to equal60/o of severalyears. The taxonomicliterature of manyof the total area of U.S. coastal marshes. the salt marsh speciesof invertebratesis often ob- Salt marshorganisms are often exposedto harsh scure, inaccessible,or difficult to interpret by the lay- conditions, which restrict the number of plant znd man,student, or ecologistor otherspecialisfuntrzin-. animalspecies. Unlike the openocean, where condi- ed in taxonomy,Well-illustrated, up-to-date identifi- tions are relatively stable,waters in the marshescan cation guidesfor the marineinvertebrates of the undergodaily rapid changesin salinity, temperature, northern Gulf are urgently needed.This guide at- oxygenconcentration, and pH. Salinityvaries from tempts to fill part of this needby treating the com- one area to the other depending on temperature, mon brackish water macroinvertebrates that live or wind, inflow of freshwater from streamsand rivers, occur in thc salt marshesalong the Mississippi Ala- rainfall, andevaporation during low tides. hzrnacoast and immediately adjacent areas of Florida In spite of theseharsh conditions, tidal marshes and Louisiana, are extremelyfertile areasin termsof the production ~Ispecies.They include protozoans,flatworms Turbel- tion and other biological agents into particulate or- laria!, roundworms Nernatoda!, gastrotrichs, cope- ganic matter known as detritus. Although organic pods, ostracods,and polychaetelarvae. The larger detritus comes from a variety of sources,salt marshes invertebrates, or macroinvertebrates, are the subject probably are one of its major sourcesin estuaries. of this guide. Animals fit into the marsh food web in several The three major groups of marine and estuarine categories according to what they consume as food. macroinvertebrates of the tidal marshes of the nor- Animals that feed directly on plant tissuesare called thern Gulf are ! polychaete worms, ! mollusks herbivores, Only a few marsh speciesare strict herbi- and ! crustaceans.This guide covers most of the vores, The meat-eaters,or carnivores,are at the top of known salt marsh speciesof these three groups from the food-chain. A third category is the detritivore, this region. One member of the Phylum Coelenterata, an animal which consumesdetritus. Actually, many an anemone, occurs in salt marshes and is included. of these animals do not utilize the basic detrital par- Oligochaetes,insects, and arachnids are excluded. In- ticles as f'ood but digest the diatoms, bacteria, fungi, formation on the recognition characters,distribution, protozoans, nematodes, and other small organisms habitat, and biology of each species is given. The that occur in or on the surfaces of the particles. taxonomy of some speciesis clarified. Most of the The detrital particles are expelled in the feces of the speciesdiscussed are also illustrated. detritivore and can be eaten again by other detriti- Binomial Latinized scientific names, which are vores.The degreeof importance of salt marsh detritus made up of capitalized generic namesfollowed by un- as a direct or indirect food source for salt marsh and capitalized speciesnames, are used for all the species estuarine animals is still being debated by ecologists, in this guide. Common names are also given when Some specialistsbelieve that phytoplankton is more feasible. The name and/or names and the date follow- important than salt marshgrasses in the food chain. ing a scientific name refer to the authority or author- The classification of marsh animals in the food ities who originally named and described the species web according to food preference, whether plant, and to the year in which it was described,The descri- animal, or detritus, is complicated by two factors. ber's name is not separatedfrom the scientific name First, the feeding habits of many salt marsh and estu- by any punctuation marks. When the describer's arine invertebrates are difficult to categorize. Many name and the date are enclosed in parentheses,it specieseat detritus, algae,and animal matter. Animals means that the first or generic name of the binomial with these diverse and unspecific feeding habits are scientific name has been changed or replaced. When called omnivores, Detritivores could be classified as a synonyms are given for a species,they are limited to specialized type of omnivore since they ingest algae the other names that the specieshas been called pre- and animal matter associated with detritus. Second, viously. the feeding habits for many salt marsh speciesvary greatly with the seasonsor other environmental fac- General References: Bagur and Ricnsrra 977!; tors. In some cases, a species may bc classified as Brown et al 978!, Carnrnen 979!; Daiber 976!; carnivorous during the winter, herbivorous during the de la Cruz 973!; Eleuterius 972!; Fleuterius and spring, and omnivorous during the summer and fall. McDaniel 978!; Gosselink 980!; Gosselink, Another complication in understanding life in Odum, and Pope 974!; Kraeuter and Wolf 974!; the salt marshes is the fact that the animals are of two Kruczynski et al 978!; Odum 961!; Shuster 9- types transitory and permanent. Many carnivores 66!; Subrahmanyamet al 976!; Teal 962!; Teal and omnivores, such as raccoons, mice, estuarine and Teal 969!; Turner 976!; Wassand Wright 9- fishes, blue crabs, penaeidshrimps, and hero~s, are in 69!. SALT MARSH MACROINVFRTEBRATES OF THE NORTHERN GULF OF MEXICO

PHYLUM CNIDARIA =COELFNTERATA!

Thisphylum contains three classes Hydrozoa; Scyphozoa jellyfishes!; and Anthozoa anemones, corals!.No publishedrecords exist of cnidariansfrom Gulf coasttidal marshes,probably because of the un- favorable habitat and the lack of intensive study by biologists,Several times I have seenin tidal marsh pondsof northwesternFlorida and Georgia hydro- zoansthat resembledHydra, althoughin eachspeci- men severalindividual polyps were connectedby a stolan.These specimens were not collected,and I havebeen unableto get additionalmaterial, Careful studiesof marshpools and the wetterareas of tidal marshes should reveal this form and possibly other cnidarians.I havefound onespecies of anthozoan,an anemone,in tidal marshesof the northeasternGulf of Mexico.

Class Anth ozoa Family Edwardsiidae

Nernatostellacf. vectensisStephenson, 1935 Figure 1

Common Name: Dwarf Mud Anemone Synonym:Nematostella pellucida Crowell, 1946 RecognitionCharacters. Small, elongate, nearly trans- parentbody up to 25 mm in length;usually with Figure 1. Nernatostellacf. vectensisfrom a tidal 16 oral tentacles in 2 rows of 8 each, marsh pool at St. Marks, Florida: a- entire animal; Distribution: Europe, North America California, b- oral end showingtentacles and mouth tentacles Massachusetts,Florida, Mississippi. partially contracted!. Habitat: Euryhaline;on mud bottoms of marshtidal poolsand ponds rich in detritusand decaying vege- PHYLUM ANNELIDA ANNELIDS! tation. Remarks:The specimensthat I have collectedfrom This phylum contains three classes Oligo- tidal marshesin Florida St. Marks! and in Mississippi chaeta earthworms!; Hirudinea leeches!; and Poly- OceanSprings! appear to be N. vectensis.Nemato- chaeta.Only the polychaeteswill be coveredin detail stella from Massachusettswas originally describedas by this guide,since they aremuch better represented a distinctspecies, N. pellucida;however, later studies in the marshes than the other two classes. by C. Hand, who comparedspecimens from Europe with those from Massachusetts and California, indica- ClassOligochaeta Oligochaetes! ted that N. vectensisand N. pellucida are the same species.Nernatostella has been observed feeding on The tidal marsh oligochaetes of the northern the polychaeteworm Hobsoniaflorida Hartman, Gulf are not well known, although severalfreshwater 1951! in New England. speciesoccur in the low salinity tidal marshes.A large References: Crowell 946!; Hand 957!; Pettibone species,Pontodrilus berrnudensisBeddard, 1891, 977!. which resembles a common earthworm, occurs in 4 sandy, upper intertidal areasalong the offshore is- proboscis feeding apparatus! or upon dissection. lands i.e, Dauphin Island and Horn Island!. There are no simpleguides to the identificationof oligochaetes; Xeanthes succinea Frey and Leuckart, 1847! however, the serious reader may wish to refer to the Figures 2 k, j; 5 b works of Brinkhurst and Jamieson 971! and Cook and Brinkhurst 973! for aid in identifying speci- Synonym: Xereis succinea Frey and Leuckart, 1847! mens of the coastal marshes and estuaries of the Recognition Characters: Relatively large worms up to northeastern Gulf of Mexico. 80 mm long; paragnathspresent on proboscis;dorsal ligules of posterior segmentsrelatively narrow and Class Hirudinea Leeches! elongate;usually with light to dark brown pigment on head region. In Gulf salt marshesthere is only one common Distribution: Cosmopolitan in temperate and sub- speciesof the ClassHirudinea the "crab leech," tropical regionsof the world, Afy:obdella lugubris Leidy, 1851, which is often Habitat: Various estuarine habitats marshes, pilings, found attached to blue crabs and to grass shrimps under debris, oyster reefs, mud bottoms! in salinities Daniels and Sawyer, 1975; Overstreet, 1978!. ranging from lessthan 5/oo to over 30/oo. In low salinity tidal marshes several speciesof Rentarks: Xeanrhes succinea is one of the most corn- freshwater leechesmay also be found. I or an identi- monly encountered nereidsin esruariesalong the east- fication guide to marine and brackish leeches,the ern United States. In salt marshes it makes shallow reader is referred to the work of Sawyer, Lawler, and burrows in the substratum around plant roots or un- Overstreet 975!. der rafts of dead marsh grassesand other debris. Xe- antbes succineais also a common associateof oysters, ClassPolychaeta Polychaetes! The sexes of X. succinea are distinct during breeding, In preparation for breeding, the bodies ot Polychaetescan be distinguishedf'rom oligochae- both males and females become highly modified for tes and leechesby the presenceof appendages para- swimming and are called "epitokes." They leave the podia! on the body segmentsand "tentacles"on the bottom to form breeding aggregationsor swarmsnear head regions;however, several of the families Capi- the surface. Hundreds of these worms can be seen at a tellidae, Serpulidae,Sabellidae!, highly modified for time swirnrning on the surface. During breeding the burrowingor for living in tubes,have lost superficial- males releasemillions of sperm cells. The bodies of ly one or both of thesecharacteristics. Though gener- the females rupture, releasing thousands of eggs, ally found in marine and estuarine environments, which are then fertilized externally in the water by somepolychaete species arc alsoknown from fresh- the sperm cells. The timing of this swarminghas been water habitats. suggestedto be related to the phasesof the moon. Of the three annelid classes,only polychaetes Xeanthes succinea is an omnivorous feeder, eat- have a planktonic larval stageor trochophore.Some ing detritus, algae,and small crustaceans.In turn it is polychaete species,especially tube-dwelling forms, eaten by marsh birds rails, seaside sparrows, and brood their young, thus bypassinga planktonic larval sandpipers!and by fishes killifishes, sciaenids!. stage.Most authorities believe that the ClassPoly- References: Bishop 974!; Camrncn 976 a, b, chaeta is more ancient than either the oligochaetesor 1979, 1980!; Cammen, Rublee, and Hobbic ]978!; the leeches. The oligochaetes are thought to have Pettibone 963!. evolvedfrom polychaeteancestors and the leeches from freshwater oligochaete ancestors, Laeo ne reis culveri Webster, 1880! Thirteen speciesof polychaetes representing 12 genera and eight families are now known from tidal I'igures 2 h, i; 5 c marshes in the northern Gulf of Mexico. Additional specieswill probably be added to this list, Recognition Characters.Relatively large worm up to 70 mm long with small head;proboscis with fleshy, Family Nereidae Nereids! finger-likepapillae; prominent, light blotches glands! on parapodia, Four speciesof this family are known to occur Distribution: Atlantic and Gulf coasts from North in northeastern Gulf tidal marshes. Nereids can be Carolina to Texas; West Indies; Brazil. distinguishedfrom other marshpolychaetes by a well- Habitat: Euryhaline Olooto over 35%%uoa!;intertidal developed head and parapodial appendagesand by to shallow suhtidal in substrata with at least some the presenceof a pair of' simpleserrate jaws. The lat- sand. ter is visible only when the worm has extended its Remarks: This species often occurs in the sand or C

4.0 mm IeI

I.0mm b, f, h, k!

Figure2. Tidal marsh nereid polychaetes andstructures: a-Namalycasris ubiuma,anterior end; b-Nama- lyc~stisabiuma, parapodia; c-heterogornph falciger;d- heterogomph spiniger;e- Stenoninereis martini,an- teriorend; f- Srenoninereismartini, specialized heterogomph seta;g- Stenoninerefs martini, parapodium; h-L~eonereis culveri, anterior end; i- I,aeonereisculveri, parapodium; j- Neanthes succinea, anterior end probosciseverted!; k- Xeanrbes succineu, parapodiurn. sand-mud substrata of tidal marshes. The linings of there. This little nereid lives and reproduces well in its burrows are a distinctive rust color. The intestines aquaria. Information on its biology indicates that it of L. culveri specimensare usually full of sand grains, can live in water with little or no oxygen content, a condition that often readily distinguishes it from References: Gardiner 977!; Pettibone 971!; Wil- other nereids that occur in tidal marshes. liams et al. <1976!. References: Cammen 976 a, b, 1979!; Gardiner 975!; Hartman 945, 1951!; Pettibone 971!. Family Pilargiidae Pilargiids! Pa randalia americana Hartman, 1947! ¹malycastis abiurna Muller, in Grube, 1871! Figures 3 a; 5 e Figures 2 a, b; 5 a Synonym: Loandalia americana Hartman, 1947. Synonyms: l.ycastopsis tecolutlensis Rioja, 1946 Recognition Characters: Earthworm-like; body usual- Lycastoidespontica $akubova, 1930 ly coiled cork-screw shapedj; head region whitish 1 ycastopsisburnmelinckiAugener, 1933 with remainder of body reddish-orange; reaching Recognition Characters: Relatively large worm up to lengths otl15 mm, up to 300 body segments:palps 100 mm long; parapodia appearing uniramous; noto- present; tentacular cirri absent; parapodia weakly de- podium reduced; proboscis not ornamented parag- veloped: notopodia minute. naths and papillae absent!, Habitat: OIigohaline and mesohaline bays and tidal Distribution: North Carolina, Georgia, Florida west marshes; in fine sand or sand-mud substrata. coast! to Louisiana. Distribution: Northern Gulf of Mexico from western Habitat: Upper intertidal in low to medium salinity Florida to Texas. tidal marshes /oa to 20%%uoo;burrowing in mud Remarks: This is a fairly common estuarine species and silt substrata or under dead marshvegetation and often present in tidal marsh habitats. l'arandaiia driftwood. americana can burrow deep into the substratum and Remarks:Little is known about the biology of this can apparently exist in areas with little or no free rare and unique nereid. In Mississippi Gulf Park!, I oxygen. No studies on the biology or life history of have found it living in nearly semi-terrestrial condi- this polychaete have been published. tions under the bark of dead pine trees that have fall- References: Emerson and Fauchald 971!; Hartrnan en into the edgesof brackish marshes.Females have 951!. large eggsindicating the possibility of an abbreviated life cycle. This species thrives in aquaria with wet Family Orbiniidae Orbiniids! mud and dead marsh grass.On the coast of Georgia, 5'coloplosfragilis Verrill, 1873! ¹rnalycastis abiuma has been reported from low sa- linity tidal matshes and as a food organism for the Figures 3 b; 5 d white catfish. References: Foster 972!; Gardiner 975!; Hartman Synonym: Hapi oscoloplosfragdis Verrill. 1873! 959!; Heard 975!; Heard and Sikora 972!; Recognition Characters: Prostomium ending in acute Subrahmanyamet al. 976!. point; branchiae dorsally arrangedbeginning between setigers 11 and 23; body widest between segments7 stenoninereis martini Wesenberg-Lund, 1958 and 14. Figures 2 e, f, g; 5 k Distribution: Atlantic and Gulf Coasts from southern Canada to northern Gulf of Mexico, Recognition Characters: Srna11worms up to 8 mm Habitat: Infaunal; burrowing in sand, mud-sand, and long with 34 body segments:proboscis not ornamen- mud substrata; estuarine; lower intertidal to shallow ted no papillae or paragnathspresent!, subtidal. Distribution: North Carolina; Gulf of Mexico from Remarks: This speciesoften occurs in damp, poorly western Florida to Texas; West Indies St. Martin Is- drained parts of rnesohahnetidal marshesalong the land!. eastern and Gulf coasts. !t is not usually found in Habitat: Brackish /oo to 30%%uao!;warm mineral salinities below '. 0/o'o. springs Florida!. tidal ponds St. Martin Island!, References: Hartman 951!; Pettibone 963!; Sub- salt marsh ponds, tidal creeks and rivers; on silt and rahmanyamet al, 976!. mud bottoms. Remarks: I have collected this speciesfrom marsh Family CapiteIIidae Capitellids! tide pools and bayous in Mississippi. It has not been reported in Alabama waters but undoubtedly occurs Many members of this polychaete family super- f igure3 Tidai marsh polyehaetes, a-Paran~alia americana, anterior end;b- Scoloplos fragilis, anterior end:e-Capitol'la '..cantata, genital setae; d-eapi1fary detae-.e-hooded hookseta; f-jIetoro>nastus filif'orrnis, anteriorend; g- Strcblospio benedicti, anterior end: h- Hobson~> florida, anterior end,i- kfanayunkia speci- osa,entire anima after Leidy, 1883;. 8 ficially resemble oligochaetes,The thorax of capitel- Recognition Characters; Body 20 to 40 mm long; lid polychaetes usually consists of the first 9 to 14 first body segment without setae; following 5 body body segments.The taxonomy of many generaof segments with only simple capillary setae; next 6 speciesis based on the number of thoracic segments body segmentshaving hooded hooks. present and on the distribution of different types of Distribution: East and west coasts of North America; setaeon these segments.In separatingestuarine capi- Europe; scattered localities throughout temperate tellid speciesof the Gulf coast from each other, one parts of the world. must determine on which thoracic body segment oc- Iiabitat: Estuarine in sand-silt substrata rich in organ- cur the modified setae called "hooded hooks." The ic matter; lower intertidal and shallow subtidal; meso- other common type of setae that are found on the haline from less than 15%%uoto over 30/oo. thorax are simple pointed setaeor capillary setae.A Remarks: This speciesis the only capitellid known compound microscope is usually required to examine from estuaries of the northern Gulf that has the the setae. Some speciessuch as Capitella capitata Fa- "hooded-hook" type of setaebeginning on the sixth bricius, 1780! have genital setae on the thoraces,and setigerous segment. Like Capitella capitata, it con- the segment on which these setae occur is an impor- structs vertical burrows. The presenceof ft. filif'ormis tant taxonomic character, Those who wish to under- is often indicated by a small cone or mound of sedi- stand more about the taxonomy of the family Capi- ment around the mouth of its burrow. tellidae are referred to a monograph by Hartman Reference: Hartman 951!. 947!. At least three capitellids Capitella capitata, Family Ampharetidae Ampharetids! Heteromastusfiliformis Claparede, 1864!, and Noto- Hobsoniaflorida Hartman, 1951! mastus sp, have been found or reported in tidal Figures 3 h; 5 f marshesalong the Gulf. Another species,Mediomas- tus californiensis Hartman, 1944, common in shallow Synonyms: /I mphicteis gunneri floridus bottoms, may occur in Gulf tidal marshes.Mediornas- Hartman, 1951 tus californiensis and Notomastus sp. a.renot present- Amphicteis floridus Hartman, 1951 ed in the text but are included in the taxonomic key Hypaniolaflorida Hartman,1951! with Capitella and Heteromastus. Hypaniola grayi Pettibone, 1953 Recognition Characters: I'ube-dwelling; body up to Capitella cf. capitata Fabricius, 1780! 30 mm long; inflated anteriorly; tapering to narrow posterior end; 4 pairs of dorsal "finger-like" bran- Figures 3 c; 5 i chiae clustered together on first few body segments; Recognition Characters: Small, thin, reddish worms prostomium with pair of small, lateral eyc spots. with 9 thoracic segments;first segmenthaving setae; Distribution: Atlantic and Gulf coasts from New Hampshireto Texas. parapodia reduced, without lobes; genital setae pre- Habitat: Estuarine; in bays, tidal marsh creeks, and sent on segments 8 9. tidal marsh pools; in variable substrata of fine sand, Distribution: 'I'emperate marine and estuarine waters sand-mud, and silt; common in oligohaline and meso- of the world. haline areas rich in detritus, or in grass beds Ruppia!. Habitat: Subtidal and intertidal in mud and silt bot- Remarks: 'I'his little polychaete is abundant in ma.rsh toms. tide pools where it constructs mucous tubes using Remarks: Capitella capitata lives in vertical burrows varying combinations of sand, mud, detritus, and in muddy substrata and feeds primarily on organic other debris. During the warmer months it repro- detritus. There are numerous records of its occurence duces. Large eggsare released,fertilized, and brooded in tidal marshes,but there are only a few reports of within the tubes of the females. When the young de- its presence in marshes along the northern Gulf of Mexico, C. capitata has been used as an indicator or- velop to the 2 to 3 setiger stage, they crawl out of their parents' tubes and begin feeding and construct- ganistn in severalenvironmental and pollution studies; ing their own tubes. Hobsoniaflorida has been report- however, recent studies indicate that it may actually ed to serve as the primary host for a trematode para- represent a complex of different forms or "species" site. Mollusks are almost always the primary host for with varying life histories and larval development. trematode parasites,and only in a.few rare caseshave References: Grassle and Grassle 974, 1976!. polychaetesbeen reported to servethis role, References'. Banse979!; Hartman 95 1!; Oglesby Heteromastus filiformis Claparede,1864! 961!; Pettibone 953, 1977!; Zottoli 974!. Figures 3 f; 5 h References: Brehm 978!; Hartman 951!; Teal Family Spionidae Spionids! 962!, 5treblospiobenedi cti Webster,1879 Figures 3 g; 5 g

RecognitionCharacters: 'I'ube-dwelling; body relative- ly small,about 8 mm;palpi long and well developed; singlepair of prominentbranchiae on anteriorcnd next to palpi,which arc nearly equal in size;second body segmentwith broadcollar. Distribution: East and west coastsof North America; South America; Europe. Habitat: Estuarinein muddysubstrata; intertidal and subtidal; in a wide rangeof salinitiesfrom lessthan 5%o to over 25%a, 0.5 Remarks:Streblospio benedicti is a commonestuarine speciesoften occuring in wetterparts of tidal rnarshes alongthe northernGulf of Mexico.This little poly- Figure4. Ficopomatusmiamiensis removed from its chaete lives in soft, mucoid tubes on muddy sub- calcareoustube, anteriorend showingventral at left! strata. '1'heyoung are brooded from the eggto the and dorsal at right! aspects. early juvenile stage within a specialized'brood pouch"on theparent worm. The small juveniles leave Family Serpulidae Serpulids! the parent'sbrood pouchand tube whenthey have developedbetwccn 9 and 13 setigeroussegments or Ficopomatusrniamiensis Treadwell, 1934! setigers. 1'igures4, 5 j References: Cammen 980!; Collier and Jones 967!; 1'ostcr 971!; Hartman 945!. Synonyms:Spbaeropomatus miamiensis Treadwell, 1934 Family Sabellidae Sabellids! Mercierellopsisprietoi Rioja, 1945 RecognitionCharacters: Small, living in smooth, Manayunlria spp. white, calcareoustubes; 12 to 19 branchiaeforming Figures 3 i; 5 l

RecognitionCharacters: Tube-dwelling; minute, 3 to 5 rnm long; prominent crown of tentacles;does not havehard, white, calcareoustubes or an operculumas does the serpulid, Ficopomatusmiumiensis Trcad- well, 1934!. Distribution: Undeterminedpending clarification of +@pt g taxonomy; two or possiblythree speciesoccuring in Mississippi Alabama estuarine waters and tidal mar- d e shes. Habitat: Oligohalincwaters in mud or silt; lower intertidal to subtidal, Remarks:Several specimens of Manayunkiaspeciosa Leidy,1858, were recently reported from a lowsalin- ity tidal marshbayou near Ocean Springs, Mississippi. Researchersin Alabama are currently investigating the taxonomy of what appearto be two additional Figure5. Representationsof adult polychaetes show- speciesof Manayunkiafrom tidal marshesand from ing their actualsizes representative of eachspecies!: a- JVamalycastisabiuma; b- Neantbes succinea; Mobile Bay. The specimensfrom Alabama tidal c- Laeonereisculveri; d- Scoloplos fragilis; e- Paran- marsheshave a closeaffinity to a Europeanform, M, dalia americana;f- Hypaniolaflorida; g- Streblospio aestuariusBourne, 1893, which has been reported as a benedicti; h- Heteromastusfiliformis; i- Capitellacf. dominant salt marshspecies in Georgia,A figure of Manayunkiaspeciosa is givento illustratethe general capitata; j- Ficopomatusmiamiensis; k- Stenonine- reis martini; 1-Manayunkia sp, body form for the genus. 10 head "plume" or "fan"; operculumspherical or fig- Common Name; Olive Nerite shaped Synonym; Neritina reclivata Say, 1822! Distribution: Florida, Louisiana; east coast of Cen- Recognition Characters: Size 10 to 14 mm; shell tral America.; Caribbean. globular, greenish-brown or light brown with surface Habitat: Epifaunai on submergedroots, shells of having many transverse,often wavy, dark lines; body mollusks and crustaceans, and other hard substrata; whorl large, expanded; spire low, often eroded; protected estuarine waters i.e. marsh tide pools! in animal with single bipectinate gill. salinities from less than 2/oo to over 25/o. Distribution: Atlantic coast from North Carolina to Remarks:This little serpulid was describedfrom tubes Florida; entire Gulf coast; east coast of Mexico to attached to the carapace of a freshwater shrimp, Central America. Macrobrachiurn americanurn Bate, 1868, collected at Habitat: Estuarine in shallow bays, ponds, bayous Miami, Florida. I have seen thousands of its tubes and tidal marshes;euryhaline in salinities from less clustered on the submergedroots of Spartina marsh than 1/oo to over 40%%uoo;lower intertidal and silt grassin the vicinity of St, Marks, Florida. It also oc- substrata rich in organic matter, submerged vegeta- curs in the low saliniry waters of Lake Pontchartrain, tion Ruppia, Valasinaria!. Louisiana. It has not yet been reported from the Remarks: This snail was long known by the name coasts of Mississippi or Alabama. No other serpulids Neritina reclivata; however, recent reports Porter, are known from tidal marshes along the northern 1974; Clarke, 1978! list this name as a synonym coast of the Gulf of Mexico. under the obscure and older name N. usnea. Since the References: Ten Hove and Weerdenburg978!. name "usnea" has been used so rarely in the past, it may eventually be surpassedby taxonomists in favor PHYLUM MOLLUSCA MOLLUSKS! of the farnilia.r and well-used name "rechvata. " This globular, euryhaline snail, one of the most Members of two classes of this phylum, the common invertebrates found in the protected shallow Gastropoda snails and conchs! and the Bivalvia bays and bayous of the Gulf coast, is often numerous clams and mussels!,are important parts of the tidal in damp, lower, intertidal areas of tidal marshes. I marsh fauna. One member of the ClassCephalopoda- have observedspecimens climbing up the lower parts the common, estuarine squid, I.olliguncula brevis of Spartina stalks to graze on encrusted alga.eand Blainville, 1823! - during warmer months enters tidal other microflora that often occur there, On Horn marsh bayous and creeks where salinities are above Island, Mississippi, Neritina occurs in tide pools that 20%%uoo.Lolliguncula is primarily a pelagic form that sometimes have salinities exceeding 40'/o, whereas occurs intermittently along the edges of tidal large numbers of specimenshave been collected in the marshes,where it feedson shrimps and small fishes. St. Marks River in Florida from water that is fresh I have collected or there are reports of at least except during very high tides. 16 speciesof gastropodsand 9 speciesof bivalves in One of the most frequent requeststhat I receive the tidal marshes of thc northern Gulf of Mexico. from laymen, students, and coliteaguesis to identify Authorities disagreeon the classifications above the the egg casesof Neritina. During the breedingseason family level subclasses,superorders, orders, etc.! for in the warmer months, females may lay over 50 small, the Classes Gastropoda and Bivalvia. For detailed white, oval, egg capsulesmeasuring about 1 mm in listings of these various taxonomic categories, the diameter, The female snail deposits the conspicuous, works of Abbott 974! and Andrews 977! should white capsules on marsh grass stems, submerged vegetation, living and dead mollusk shells, dead wood, be consulted. and any other hard surfacesavailable. When laid, each egg capsule usually contains from 60 to 80 eggs. The Class Gastropoda Gastropods! capsule ruptures several days after being laid, releas- Fainily Neritidae Nerites! ing planktonic veliger larvae with small, embryonic shells, The veliger larvae remain in the plankton and The family Neritidae, along with several other grow until they settle to the bottom assmall juveniles families, has been placed in a group called the Archio- to begin a bottom-dwelling existence. gastropoda =Diotocardia!. The gastropods belong- Populations of ¹ritina in the bays and marshes ing to this group are characterized by a pair of uni- are thought to be an important food for wild ducks. pectinate gills, or as in Neritidae, a single bipectinate I have observed blue crabs and Gulf toadflsh eating gill. adult snails and seasidesparrows eating juvenile snails. The shells of N. usnea from marsh tide pools often Neritina usnea Roding, 1798! are encrusted with barnacles Balanus spp.!, and Figure 6 bryozoans Membranopora!. In marsh pools at St. 11 Marks, Florida, shellswere found fouled with tubes the males of these forms can often be separatedby ot'serpulid polychaetes Ficopomatus rniamiensis!, the numberand kind of papillaeon their copulatory References: Andrews 935!; Andrews 977!; organs verges!. Other charactersused to separate Clarke 978!; Porter 974!. closely relatedhydrobiid speciesinclude the number of gills and morphologyof the femalereproductive system.This requires refined dissecting and histologi- cal techniques,which are beyond the scopeof this guide.Help from an expertwill oftenbe requiredto identifymany hydrobiid snails because of theirsmall sizesand similar appearance.

Lit toridr'nopspalustris Thompson, 1968 Figure 7 e; 8 d

RecognitionCharacters: Small, reaching4,5 mm in length; shells similar to Littoridinops rnonroensis Frauenfeld,1863!; vergeof male usuallywith single row of 8 to 15 papillaeon convexmargin and 2 to 3 subterminalpapillae on concavemargin. Distribution: Coast of the Gulf of Mexico from western Florida Yankeetown! to eastern Louisiana Lake Borgne!. Habitat: On muddy or silty substratarich in organic matter; intertidal in marshes and shallow bays im- mediately adjacentto land; or subtidal, associated CLX" with widgeongrass Ruppia! in shallow bayousand bays; wide range of salinities from nearly fresh to over 25%a. Remarks: In the wetter parts of tidal marshesthis hydrobiid is often one of the most commonand im- portant invertebrates.These little snailsapparently feed on microflora diatoms, filamentous algae,bac- teria! and other organic matter occurring on the marsh floor or on the surfacesof living or decaying Figure6. Neritinausnea =N. reclivata!:dorsal and vegetation.I have found thesesnails in the stomachs ventral aspectsof shell. of blue crabs, killifishes Fundulus!, and seaside sparrows,and undoubtedlythey are eatenby other Family Hydrobiidae Hydrobiids! animals such as mud crabs, rails, and ducks. Littoridinops palustrisis similar to L. rnonroen- Members of this family can be found in large sis and to Z. tenuipes Couper, 1844!, an east coast numbersin marshpools and other wet areasof Gulf species.On the Gulf coast,L. palustrisoccasionally tidal marshes;however, they often are overlooked by occurs with L. rnonroensis in brackish water' tidal the casual observer becauseof their very small size. ponds;however, L. palustris usually does not occur Eight or more speciesoccur in the estuarineareas in the more open pond habitats preferred by L. nron- of the northern Gulf of Mexico, and of these, at least roensis, and L. rnonroensisis not commonly found in six can be found in tidal marsh habitats. Hydrobiids the intertidal marsh habitats where L. palustris is feed on detritus and its associated microflora. Since common. Often the shells of' L. palustris from sub- their populations are often large, in some casesex- tidal areasin shallowbayous and bays have a thicken- ceeding 10,000 snails per squaremeter, and since ed or swollen area on the l.ast body whorl near the they havea rapid feedingrate, thesesmall snails may aperture.The reasonfor the occurrenceof this phe- be ecologically important in some tidal marsh nomenon in subtidal populations is unknown. systems. On the southeast Atlantic coast, L. tenuipes oc- The taxonomyof the Gulf speciesis still unset- curs in the samehabitat types occupiedby L. palus- tled, and severalnew speciesmay be present.The tris on the Gulf coast. Although the two speciesare snells of some speciesare almost identical; however, very similar, the verge of L. tenuipeshas an extra Figure7. Hydrobiid shells; a Texadinasphinctostoma; b Onobopscf. jacksoni; c Heleobopssp, form 8!; d Pyrgopborus sp.; e Littoridinops palustris. 13 clusterof 3 to 10papillae at its base Figure 8 c!. keel-likeprocess directly adjacent to theopening of Reference: Thompson 968!. the spermduct Figure8 f!. Theverge of another form I'orm B!, which occurssporadically along the northeasternGulf, has finger-likeprocesses instead Littoridinopsrnonroensis I'rauenfeld, 1863! of the wide, keel-likestructure Figure 8 g!. Another Figure 8 b type FormC!, whichhas a vergesimilar to FormB, hasa shellwith distinct striationson the whorls that Synonyms:l.ittoridina rnonroensis Frauenfeld,1863! are similar, but not as strongly pronouncedas those l,ittoridinopssp. A: Taylorin Andrews onOnob ops spp. Heleobops docirna Thompson,1968, 977! known from rnarshesand rnangrovesin the southern RecognitionCharacters: Shell smooth, similar to Lit- half of Florida, is related to Form B but lacks the toridinopspalustris; verge with 2 or3 rowsof papillae subterminalsac-like glands on its verge.Fred Thomp- on convexmargin, 2 to 3 individualglands on con- son andI arc attemptingto clarify the taxonomyof cave margin. this groupand to publishtaxonomic papers on the Distribution: Atlantic and Gulf coastsfrom South speciesfrom the northeastern Gulf. Until thenI sug- Carolina Georgetown! to Texas Galveston!. gestthat theybe classifiedas Heleobops sp. Forms Habitat: On mud-silt bottoms or submergedvege- A, B, andC!. All threeforms lay relativelylarge, in- tation; in fresh and brackishwater coastallakes, dividua,l,egg capsules. There is no pelagicveliger ponds,and tide pools, stage.A singlesnail emerges f'rom each capsule after Remarks: This snail was commonin severaloligo- a weekor more,depending on the temperaturedur- halineponds on Galvestonisland in 1975,and large ing incubation. populationsexist in severalfresh and oligohaline Reference:Thompson 968!. pondson HornIsland, Mississippi. I have also exam- Onobopscf.jacksoni Bartsch, 1953! ined specimensfrom tidally influenced,freshwater pondsnear Georgetown, South Carolina, Spccirnens Figures 7 b; 8 e have been collected from tide pools in Juncus and Common Name: Jackson'sHydrobiid spartinamarshes at St.Marks, Florida, and Dauphin Synonym:liydrobiajaclrsoni Bartsch,1953 Island,Alabama. The developmentof its youngis RecognitionCharacters: Shell elongate, whorls im- similarto that of Heleobopswith youngsnails hatch- pressed,striations; verge siinple without glands;gill ing directlyfrom relatively large egg capsules attach- with 20-241amellae;operculum with about 3 whorls. ed to mollusk shells and other hard substrata. Distribution: Atlantic and Gulf coastsfrom Maryland References:Andrew> 977!; Thompson 968!. to Mississippi. IIabitat: Mesohaline;in tide pools or wet areasof lleleobops spp. Juncusand Spartina marshes; mud or mud-siltbot- Figures7 c; 8 f, g toms with organic matter. Remarks:As in the caseof Heleobops,a complexof RecognitionCharacters: Shells relatively narrow with two or three speciesmay be presentin the northeast- fine striationson whores;verge with 6 to 8 suction- ern Gulf tidal marshcs.On Horn Island, Mississippi,a cup-likeglands on outcr convex!margin, with 2 sub- largeform almosttwice as large as the normal size re- terrninalglands smaller and distinctly separated from portedf'or O.jacksoni is presentin marshpools with proximalg}ands; subtcrminal process on inner margin mud bottoms and large amountsof organicmatter. adjacentto openingof spermduct. Also on Horn Island I found populationsof a minute Distribution: Gulf coa~tfrom northwestFlorida to form about half the sizeof typical O.jacksoni. The Mississippi. cggcapsules of all threesize groups appear similar. A IIabitat: Nearor adjacentto openGulf; mesohaline; secondspecies of Onobops, O. crassaThompson, intertidal to shallovvsubtidal; in tidal.marshes, shal- 1968, was describedfrom southernFlorida. Though low baysand inlets; on mud,mud-silt, and sand-silt similarto O.jacltsoni, the snailhas more gill lamellae 6-28! andusually four opercularwhorls, bottoms, Reinarks:'i'hcrc appear to be two, or possiblythree, As in the caseof Texadinaspbinctostoma Ab- newspecies of Heleobopsin the northeasternGulf bott and Ladd, 1951, after severaldays of incubation, tidal marshes.All of the specimensof Heleobopsthat a well-developed,shelled veliger larva emerges from I have collected came from areasof moderate salini- eachcapsule. Further taxonomic, ecological, and life ties near the open Gulf. Three distinct vergetypes historystudies are needed to determinewhether one and at least two shell types can be recognized.The or more speciesare involvedin the northernGulf vergeof onefornax Form A!, knownonly from habi- marshes. tats at or near St, Marks, Florida, has a wide, low, Reference:Thompson 968!, Figure 8. Hydrobiid verges male copulatory organs!: a. Pyrgophorus sp.; b Littoridinops monroensis; c Littoridinops tenuipes; d Littoridinops palustris anterior part of body with verge!; e Onobops cf. jacksoni; f Heleobops sp. form A!; g Heleobops sp. form B!; h Texadinasphinctostoma. 15

Pyrgophorus sp. adultspecimens; male verge with 5 to 6 glandsalong outer margin. Figures7 d; 8 a Distribution: Coastof the Gulf of Mexicofrom Ala- bama Mobile Bay! to the YucatanPeninsula, RecognitionCharacters: Shells similar in sizeand Habitat: Estuarine,oligohaline to lower mesohaline; shapeto Littoridinopsbut withdistinct keel or ridge in shallowbays and bayous on silt andfine sand-silt nearanterior marginof whorls;ovoviviparous young bottoms, snailsoften visible through semi-transparentshell of Remarks: I have collectedT. sphinctostornaf'rom female!;verge similar to Littoridinopspalustris, but oligohalinetidal marshpools in Mississippi,but in usuallywith a singlepapilla on concaveside near generalit is rarein tidalmarsh habitats. It usuallyoc- base. curs,often in largenumbers, in subtidalareas on the Distribution: Mississippi Horn Island!. bottom of shallowoligohaline bays, where it is com- Habitat: Mesohalinemarsh pools on muddy or silty monly associatedwith the clam, Rangt'acuneata bottoms rich in detritus, Gray,1831!, and with anotherhydrobiid, Probythi- Remarks:This species or form of Pyrgophoruslacks nella =Vioscalba!louisianae Morrison, 1965!. Texa- thespines on thewhorls that are so often character- dinasphinctostorna lays egg capsules containing a sin- istic of this genus.It is similarto thc unspinedform gleegg, which ruptures after several days and releases of P. platyracbis'I'hompson, 1968, which was de- a veligerlarva with a well-developedshell. scribed from southernFlorida and was recently re- Anotherspecies of Texadina,T. barretti Mor- ported from Louisiana. rison, 1965!, occasionallyoccurs with T, sphincto- Spinedand unspined forms of P,platyrachis oc- stoma on silt-mud bottoms. Texadinabarretti was cur in both freshand brackish waters, The spinedand originallyplaced in the genusOdostornia Family unspinedforms of anotherspecies, P. =Lyrodes!par- Pyramidellidae!and was later listed under the name vulus Guilding,1828! also have been reported from Hydrobiaboonae Morrison, 1973, It appearsto be a brackish waters in Louisiana. The speciesfrom Horn subtidalspecies and is not currentlyknown from Island,Mississippi, may represent an ecotype ecologi- tidal marsh habitats. cal form! of P. platyrachis,P, parvulus,or P. cornatus References:Abbott and Ladd 951!; Heard979!; Pfeiffer,1840! or maybe a newspecies. Additional Taylor in Andrews977!. researchwill be neededto determinethe taxonomic status of this species. Family Assimineidae I'emalesof the genusPyrgophorus are the only hydrobiidsfrom the northeasternGulf of Mexico Assirninea succinea Pfeiffer, 1840! that do not deposittheir eggs.Instead, the eggsare Figure 9 brooded within the female until the young snails are fully formed.This type of reproductivedevelopment Common Name: Atlantic Assiminea is termed"ovoviviparity." In fact, femalesof the Synonym:Syncera succinea Pfeiffer, 1840! genusPyrgophorus can be easily identified while they RecognitionCharacters: Small, hydrobiid-like snails; are broodingtheir young,since the youngsnails can lengthunder 3 mm;shell smooth; fine, thread-like be seenthrough the semi-transparentshells of the ridgeoften around anterior margin of bodywhorls; females'bodies. When the young are released,they narrow,slightly raised callus on marginof innerlip; are each contained within a thin, membranous, egg eyeson tips of reduced,stubby tentacles. capsule.The juvenile snails immediately rupture the Distribution: U.S. Atlantic and Gulf coastsfrom eggcapsules and crawl out on to the sedimentto Massachusscttsto Texas; Brazil; Bermuda. beginfeeding and growing. As in thegenera Littori- Habitat; Upperintertidal zone of saltmarshes and dinopsand Heleobops, Pyrgophorus bypasses a plank- mangroveswamps, moderate to highsalinities; often tonic larval stage. amongdebris or on basesof plants. References:Bridgeman 969!; Garrettand Dundee Remarks: This little snail superficiallyresembles a 979!; 'I'hompson 968!. hydrobiid,but it canbe distinguishedfrom those aquaticforms by its short,stubby tentacles with the Texadinasphinctostorna Abbott and Ladd, 1951 eyeson thetips and by its abilityto toleratedesicca- Figures 7 a; 8 h tion, Thehydrobiids, which have well-developed ten- tacleswith the eyesat theirbases, are unable to with- Common Name; Small-mouthedI Iydrobiid stand desiccation even for a few minutes. Develop- Synonym:Littoridina Texadina!sphrnctostoma Ab- ment of' A, succinea,as in manyhydrobiids, is direct. bott and Ladd, 1951. Femalesdeposit egg capsules, each containing a single RecognitionCharacters: Aperture constrictedin egg,on damp leaves or otherdebris in upperintertidal 16 zones, After several weeks of development, juvenile Ceritbideaphculosa Menke, 1829! snails emerge from the capsulesand begin crawling Figure 10 c and feeding among the damp debris,

References: Abbott 974!; Andrews 977!; Marcus Common Name: Plicate Horn Shell and Marcus 964!. Recognition Characters: Severalold varices present; adults reaching over 26 mm in length, Distribution: Gulf coast from Alabama to Texas; east coast of Central America to northern South America Venezuela!; West Indies. Habitat: Muddy substrata in coastal marshes and mangroveswamps; moderate to high salinities. Remarks: The plicate horn shell is the only speciesof its genus known to occur in the northwestern Gulf of Mexico. Its shell is distinguished from the other two northwestern Atlantic species,C. costata de Costa, 1778! and C, scalarif'ormis Say, 1825!, by irregular, swollen,vertical ridges old varices!.Ceritbidec plicu- losa appearsto bc more similar and closely related to a west coast species,C. californica Haldeman, 1840, than to the two northwestern Atlantic specie».Like C, plic~losa, C. californica has old varicesmarkings on its shell; these structures do not occur on the shells of Figure 9. Shell of Assimineasuccinea. C. costata and C, scalarif'ormis. Family Potamidae IIorn Shells! Plicate horn shellsare known to be an important food of shorebirds and to serveas host for a variety Genus Ceritbidea Swainson, 1840 of larval flatworm trematode! parasites.These snails feed on algaeand detritus occurringon the muddy Three speciesof this genusoccur in salt marshcs marsh floor and at the basesof marsh plants. of the northern Gulf, The genus is characterizedby References: Abbott 974!; Andrews 977!, Be- an elongate shell with axial ribs, 10-1S convex body quaert 942!; I'otheringharn and Brunenraeister whorls, and a flared, thickened, outer lip in adults. 975!.

Figure 10. Shells of Cerithidea spp.; a C. scalariformis; b C, costata; c C. pliculosa. 17

Cerithideascalariformis Say, 1825! Common Name: Marsh Periwinkle Figure 10 a RecognitionCharacters; Adults up to 23 mm in length, slightly longer than broad; shell thick, stout, Common Name: I.adder I lorn Shell having8 to 10body whorls with manyevenly spaced, Recognition Characters:Body without old varices; spiralgrooves; last body whorl abouthalf lengthof approximatelysame size as C. pliculosa;last two whole shell; color of shell light gray or grayishwhite body whorlswith stronglydeveloped axial ribs; base with reddish-brown flecks on the spiral ridges; inner of shell with severaldistinct spiral ridges;outer lip margin of outer lip with reddish-brownflecks corre- of aperturestrongly flared. spondingto spiralgrooves; smooth margin of innerlip Distribution: Atlantic and Gulf coasts from South palebrownish-orange. Distribution: Atlantic and Gulf coasts from New Carolina to northwestern Florida; West Indies; York to Texas excluding southern Florida. Bermuda. Habitat: Upper intertidal zonein mangroveswamps Habitat: MesohalineSpartina-Juncus marshes. and salt marshes; on mud to sand-mud substrata; Remarks: This speciesis probably the best known salt marsh invertebrate of southeastern North moderate to high salinities. Remarks: This speciesis often associatedwith America. It is absent from southern Florida where Melampusbidentatus Say, 1822,Melampus coffeus salt marshesare replacedby mangrovesand where its L., 1758!, and C, costata de Costa, 1778!. It can tropicalrelative Lrttorina angulifera Lamarck, 1822! live higher in the intertidal zone than can C. costata is common. and C. ph'culo,saand can withstand longer periods of Femalemarsh periwinklesshed their fertilized desiccation up to three weeks!. Cerithidea scalari- eggsdirectly into the waterduring high tides. After a formis is part of the diet of many salt marsh preda- shortperiod of development,the eggshatch and de- tors, including mud and blue crabs, rice rats, rails, and velop into planktonicveliger larvae. The veligerstages large shore birds. 'I'he larvae of over 10 different spe- cies of trematode parasites are known to develop in the tissues of this marsh snail. References: Abbot t 974!; Bequaert 942!; Hollirnan 961!,

Cerithidea costata de Costa, 1778! Figure 10 b

Common iVame: Costate Horn Shell RecognitionCharacters: Small; one-half length of C. pliculosaand C. scalariformis;no old varicespresent; axial ribs indistinct on last two body whorls. Distribution: Atlantic and Gulf coasts from South Carolina to northwestern Florida; West Indies. Habitat: Intertidalzone in mangroveswamps and salt marshes; on mud, sand-mud substrata; moderate to high salinitics. Remarks: This speciesusually occurs with its larger relativeC. scalarifbrmis.In northern I'lorida I found populations of C. costata occurring in Spartina- Juncusmarshes as far westas Cape San Blas, Like the other two Gulf,speciesof Cerithidea,it is eatenby mud and blue crabsand by a variety of shore birds. It is also a host for the larvae of many trematode parasites. References: Abbott 974!; Bequaert 942!.

Family Littorinidae Periwinkles! Littorina irrorata Say, 1822! Figure 11. Marshperiwinkles on Spartinamarsh I'igures 11, 12 grassstalks. 18 gradually changeinto small juvenile snails which set- tle on the marsh floor and immediately begin feeding and growing, Marsh periwinkles can live for several years. During low tide they feed on detritus and algae from the marsh floor and the bases of marsh grass stalks. Littorina irrorata has been the subject of several ecological and behavioral studies, some of which are cited in the references.Although they havegills, these !', !.!! snails rarely enter the water and then only for short ;5; periods of time, Usually, as the tide rises,they retreat up marsh grass stalks. This apparent avoidance of water is thought to be due, in part, to a behavioral response to avoid predation by blue crabs. Gliding over the marsh floor, these snailsleave mucous trails, which can be detected and followed by other marsh periwinkles. References: Abbott 974!; Alexander 979!; An- drews 977!; Bandel 974!; Bequaert 943!; Bing- Figure 13, Shell of common crown conch Melon- ham 972!; Fotheringham and Brunenmeister gena corona!. 975!; Hall 973!; Hamilton 976, 1977, 1978a, 1978b!, Odum and Smalley 959!. Habitat: Subtidal and intertidal, in or along the edges of mesohaline 2%a to over 30%o! bays, usually as- sociatedwith oysters,Crassostrea virginica Gmclin, 1791!. Remarks: This specieshas long beenconsidered an important predator of oysters and other mollusks; however, studies have demonstrated that it also com- monly feedson detritus and deadanimal matter and thus may servean important role as scavenger. The females deposit strings of disc-shapedegg capsules,often attachingthem to oystershells. Fach capsuleusually containsfrom 100 to over 300 eggs. The larvae "hatch" from the egg capsuleafter approx- imately 20 daysof' incubation.They havewell-form- ed shellsand apparentlydo not go through a plank- tonic pelagic! stage. l have often observed crown conchs associated with oysters on the edgesof Spartina rnarshesof northwestern Florida. Their occurrence in Alabama is sporadicand apparentlydoes not occurin the United Figure 12. Shell of Littorina irrorata marsh peri- States west of Mobile Bay. winkle!. References: Abbott 974!; Hathaway and Wood- burn 961!,

Family Melongenidae Whelks! Family Pyramidellidae Pyram Shells! Melongenacorona Gmelin, 1791! Sayella spp. Figure 13 Figure 14 Common Name: Common Crown Conch RecognitionCharacters: Relatively large shell 0 to RecognitionCharacters: Tentacles flat, triangular,not 100 mm!; prominentcrown of spineson shoulderand extendingbeyond front of large flat foot; front of baseof shell; well-developedsiphonal notch present. foot "squared-off," posterior to basesof tentacles; Distribution; Southern Florida and Florida Gulf shell elongatewith end of spire blunt, often eroded; coast. aperturewith obliquefold on inner margin. 19

Distribution: Gulf Coast from Florida St. Marks! to FamilyMelampidae Melampid Snails! Mississippi Horn Island!. Habitat: MesohalineSpartina tidal marshpools and Snailsbelonging to the family Melampidae,or pondson muddy or silty bottoms;collected with the Elliobiidae,lack gills. They breatheor respirewith a anthozoans Nematostella! and the hydrobiid snails "lung" that is formed by a modificationof the Heleobops and Littoridlnops!, mantle-cavity,They are consideredone of the most Remarks: The taxonomy of Sayella, Odostomia, and primitivemembers of the"air-breathing" gastropods, other generabelonging to the family Pyramidellidaeis the Pulmonata.Two speciesof melampidsnails occur still unsettled and as a result often very confusing. in northern Gulf tidal marshes. Based on Abbott's 1974 treatment of the family, I considerthe specimenscollected from tidal marshes kfelampusbidentatus Say, 1822 at St. Marks and Horn Island to belong to the genus SayellaDali, 1885. Other authoritiesconsider forms Figure 15, left that are closelyrelated to this speciesto be members of the genusOdostomia, such as O. producta C. B. Common Name: Eastern Melampus Adams, 1840! and O. livida Rehder, 1935. Recognition Characters; Moderately small 0-15 Membersof the genusSayella are usually con- mm!; shell ovateconical;broadest anteriorly with last sideredectoparasites of other invertebrates,especially bodywhorl approximately three-fourths body length; polychacteworms and bivalvemollusks. As a modifi- spirelow andblunt with fine, spiral,incised lines or cation I'or a parasiticexistence, the radula of Sayella striationson whorls;aperture elongate with two folds and other pyramidellidshas been replaced by a tubu- on posteriormargin of inner lip folds on innerlip lar proboscis,used when feedingon the host which look like teeth, or denticles, hence the specific name is unknownfor Sayellafrom the'northernGulf!, "bidentatus"!; other lip of aperaturewith 1 to 4 Sayellasuperficially resembles hydrobiid snails, small, thin, elevated,spiral ridges lirae!; operculum with which it is often collected. It is distinguished absent;color brownish,often with severaldark bands, from the hydrobiidsby the "squared-off"foot, flat, especiallyon younger,smaller specimens. triangulartentacles, and a fold on the inner marginof Distribution: Atlantic and Gulf coasts of North the shell's aperture. America, southern Canada to Texas; Bermuda; West References; Abbott 974!; Andrews 977!; Mor- Indies. rison 939!. Habitat: Salt marshes and mangrove swamps; upper intertidal; exposedto wide rangeof salinities to 50%%u.o;occurring on marsh grassstems, under inter- tidal debris wood, dead grass!. Remarks:This little bean-shapedsnail is one of the more characteristic snails in tidal marshes of the northern Gulf. It is amphibiousbut usually avoids water. It also avoidsbright light and during sunny, hot daysusually retreats to shadedareas under logs, deadmarsh grass, and other intertidal debris!.Melam- pusbidentatus is mostactive at nightand feeds then or during periods of reducedsunlight. It feedson algaeand detritus, which it obtainsfrom the bases of marsh stems and from the marsh floor, and on decay- ing animalmatter. Afelampus bidentatus, in turn, servesas food for other animals, including mud crabs, blue crabs, fishes, wild ducks, rails, seasidesparrows and rice rats, During the warmermonths, adult snailsusually depositgelatinous egg masses, which generally con- tain 500 to 1000 eggs,on damp or wet areasunder debris on the marsh floor. Unlike other pulmonate snails, M. bidentatus and its relatives have a plank- tonic veliger stage.The hatching of larvaeand the Figure 14. Shellsof two differentSayella spp. a- settlingof the post-larvaein the upper intertidal specimenfrom CedarKey, Florida; b specimen regionof' the saltmarsh corresponds to thephases of from St. Marks, Florida. the moon and the resultant tidal effects, Young snails 20 become sexually mature at about 5 mm in length. Melarnpusbidentatus lives for 3 to 4 yearswith adults Detracia floridana Pfeiffer, 1856! attaining lengths of up to 15 mm. Figure 16 Another closely related species, Melampus coffeus L., 1758!, overlapswith M bidentatus in the Common Name: Florida Melampus coastal mangrove regions of southern Florida and the Synonym: Melarnpusfloridana Pfeiffer, 1856 West Indies. Although the shells of the two species Recognition Characters: Shell small to 8 mm!, are very similar, M. coffeus, which is usually larger, glossy, biconical, spires higher than M bidentatus, lacks spiral, incised lines on its spire see Figure 15, often eroded, lacking spiral striations; aperture with right!. posterior inner margin having large denticle fold!, References:Abbott 974!; Apley 970!; Fothering- smaller denticle located anteriorly, outer lip of ham and Brunenmeister 975!; Hausman 936a, b!; aperture with approximately 10 small, thin, elevated, IIolle and Dineen 957, 1959!; Morrison 958a, b!; spiral ridges lirae!; color dark brown, often with a Russell-Hunter et al. 972!. few light bands, Distribution: Atlantic and Gulf coasts from New Jersey to Louisiana, Habitat: Upper intertidal zone in brackish marshcs, on marsh grassstalks, or on or under debris on marsh fioor. Remarks: In the northern Gulf this species often occurs with its larger relative M. bidentatus in brack- ish Juncus marshes. Unlike M. bidentatus, which can also occur in high salinity marshes near the open Gulf, D. jloridana appearsto be restricted to the low salinity marshesof tidal rivers, bayous and bays. The life cycle is apparently similar to that of M. bidenta- tus, but D, floridana deposits larger and far fewer 0-50! eggsper egg mass.The eggshatch into plank- tonic veliger larvae. Like M bidentatus, it feeds on algae and detritus and is itself a common food of crabs, fishes, ducks, rails, seasidesparrows, and rice rats, In some east coast tidal marshes it often occurs in large numbers; one authority estimated 4 billion snailsper squaremile in the Virginia tidal marsh, Figure 15. Shellsof melampidsnails: left Melam- References: Abbott 974!; Morrison 951, 1953, pus bidentatus;right Melampuscoffeus. 1964!; Halle and Dineen 959!.

Class Bivalvia =Pelecypoda! Bivalves!

Clams, mussels,and oysters belong to this highly modified class of mollusks. The class is characterized by the absence of a head and radula and by the presence of a hatchet-shapedfoot and a shell made up of two valves.The valves of the shell are attached by a hinge with an associatedligament and by one or two adductor muscles. In addition to the shape and external morphology of the valvesof the shell, other characteristics e.g., the type and number of teeth on the hinge, the location of the ligament, the shapeand location of the anterior and posterior adductor muscles, the shape of the pellial sinus, and the loca- tion of the pellial line! are important taxonomic charactersused to identify bivalves. Many bivalves are adapted for digging with a Figure 16, Shellof Detraciafloridana, modified foot, and they usually live completely or 21 partiallyburied in thesediment infaunal!. Other bi- occursin largenumbers. The adultsare often eaten valves,such as many species of rnussels,are epifaunal, by raccoonsand blue crabs. oftenattaching externally to the shellsof otherbi- Thoughquite different, P. carolinianais often valves,roots, pilings, or other substrata. confusedwith Rangiacuneata Family Mactridae! Fivespecies of bivalvesoccur cornrnonly in tidal Figure18!. These two speciesare both infaunal and marshesalong the northern Gulf' of Mexicoand an- aresuperficially similar in shapeand size, but there- other four specieshave been listed from Gulf semblancestops there. Rangia nearly always is found in the subtidalzone in baysof low salinity; very rare- marshes, ly doesit occurin the intertidalareas of tidal

Figure 17. Shell of Polymesodacaroh'niana,

Family Corbiculirlae Alarsh Clams! PolymesoJa caroliniana Bose, 1802! Figure 18, Shell of Rangia cuneata. Figure 17

Common Name: Carolina Marsh Clam RecognitionCharacters: Moderate-sized5 to 40 mm!, deep-bodied,suboval-shaped clams; beaks umboncs!close together; ligament narrow, external; three subequalcardinal teeth; one anteriorlateral tooth: one posteriorlateral tooth, not extendingto posterioradductor scar; inner surfaceof living or recently dead shells often pale blue; periostracum prominent,dark, often eroded away on andadjacent to beaks. Distribution: Virginia ro I'exas excludingsouthern Florida!. Ilabitat: Intertidal,occasionally subtidal, oligohaline andmesohaline tidal marshes; in mud,mud-fine sand, or fine sand-silt substrata. Remarks:The Carolina marsh clam is oneof the most characteristicspecies tound in tidal marshesof the southeasternUnited States, In protected Juncus marsheswhere salinity is low, this speciesoften Figure19. Shellof Polymesodarnaritima. 22 marshes.The shell of Rangiais muchthicker, andthe beaksare noticeablymore separatedthan thoseof P. caroliniana.The most strikingdifference between the two clams is the hinge area. In R, cuneata there is a deep pit, or chondrophore, between the cardinal teeth and posteriorlateral tooth. This pit containsa tough pad or ligament-like structure, the resilium, which causesthe valvesof the shell to gapeopen when the adductormuscles relax. The posteriorlater- al tooth is very long, reachingnearly past the posteri- or adductor muscle,and its marginis finely serrate. Another speciesof Rangia,R. =Rangianella!flexuosa Conrad,1839! can be distinguishedfrom R. cuneata Figure 20. Shell of Geukenst'ademissa. by its more wedge-shapedshell and shorter, non- serrate, posterior, lateral tooth. Recognition Characters: Moderate size to over 100 References: Abbott 974!; Andrews 977!; An- mm!; elongate with rounded posterior margin; over drews and Cook 951!; Van der Schalie93 3!. 25 strong, radial, beadedribs; no teeth on long hinge; with byssus;epifaunal or infaunal, Polymesoda maritima Orbigny, 1842! Distribution: Atlantic and Gulf coasts from Maine to Figure 19 Texas; California introduced!. Habitat: Intertidal or rarely subtidal juveniles!; Common Name: Florida Marsh Clam; Orbigny's mesohaline tidal marshesin mud among marsh grass Marsh Clam. roots infaunal! or attached to exposed marsh grass Synonyms:Pseudocyrena maritima Orbigny, 1842! roots epi faunal!. Pseudocyrenafloridana Conrad, 1846! Remarks:Many authoritiesconsider the populations Recognition Characters: Shell smaller, more variable; of G. demissa in southeastern Florida and the Gulf to lessrobust andmore elongatethan that of P. carolini- be a distinctsubspecies, G.d. granosissima Sowerby, ana; lacks thick, dark, periostracum; inner surface of 1914!. This subspeciesis characterizedby more and living or recently deadshells partially or completely smoother ribs than the typical Atlantic form. purple; outer surfaceof shelltinged with pink or light The ribbed musseloften occursin largecolonies purple. on the tidal marsh floor. Often juveniles and sub- Distribution: Gulf coastof North Americafrom Key adultsare present on theexposed roots of marshgrass West, Florida, to the Yucatan Peninsula. Juncus and Spartina!.In a tidal pond at St, Marks Habitat: Salt marshesand mangroveswamps; near Refugein Florida, I havefound largenumbers of rib- surface, usually in sand and sand-mud substrata; in bed musselsattached to the submergedroots of areasof moderateto high salinitiesnear or adjacent Spartina, With these mussels,often attached to them, to open Gulf water. were equally large numbers of Conrad's false mussel, Remarks: This species is much more colorful than Mytilopsis =Congeria!leucopbaeta Conrad, 1831!. its drab cousin,P. caroliniana,which usuallyoccurs As the commonname implies, Mytilopsis is not a true in muddier areas and in lower salinities. In the north- mussel, although it is often confused with mussels ern Gulf there are well-establishedpopulations of P. becauseof its elongateshell and byssalthreads see maritima in severalcoastal marsh systems of north- Figure 21!. It belongsto the family Dressenidae, west Florida. As yet, this clam is not known from Alabama-Mississippitidal marshes,which may be due to the lower salinities or the lack of collections in this region. References: Abbott 974!; Andrews 977!.

Family Mytilidae Mussels! Geukensiademissa Dillwyn, 1817! Figure 20

Common Name: Ribbed Mussel Synonyms: Arcuatula demissa Dillwyn, 1817! Modiolus demissus Dillwyn, 1817! Figure 21. Shell of Mytilopsis leucophaeta. 23 whichis only remotelyrelated to the familyMytil- idae. Twoother species of truernussels, the hooked musselIschadium recurvum Rafinesquc,1820! and the papermussel Amygdalum pa~yrium Conrad, 1846!,occasionally occur in tidal marshes.The hook- ed musselis epifaunal,often attachedto oystersor evento the exposedshells of the ribbedmussel. It differsfrom the ribbedmussel by havingfewer and relativelylarger ribs, not beaded,and a hookedan- teriorend secI'igure 22!. The paper mussel, usually occurringsubtidally in soft bottoms,is generally infaunal.Its shellresembles that of theribbed mussel but is smaller,glossy, and lacks ribs seeFigurc 23!. Thepaper mussel is alsoquite colorful, often with finegreenish and redcIish markings. 'I'he ribbed mussel is the only musselwell- adaptedfor livingin tidalmarshes along the northern Gulf of Mexico.The false,hooked, and paper mussels shouldnot be consideredtypical marshspecies, since theyoccur only marginallyin tidalmarshes and are betteradapted to otherestuarine habitats. Figure24. Shell of Cyrenoidaflloridana. References: Andrews 977!; f otheringhamand Brunenmeister975!; Kuenzler961!; Stiven and Common Name: Florida Marsh Clam; Dali's Marsh Kuenzler 979!; Teal 962!. Clam. RecognitionCharacters: Shell small up to 10mm!, oval, thin, fragile, moderatelydeep; periostracum thin, inconspicuous;left valvewith delicate,biden- tate, cardinaltooth anda prominent,narrow, blade- like, anterior,lateral tooth; posterior,lateral teeth appearingabsent; foot, whenextended; extremely narrow and long. Distribution: Atlantic and Gulf coastsfrom Delaware to Louisiana. Habitat: Brackish from lessthan 1%0to over25%a! in marshesand mangroves;in damp intertidal areas under decayingvegetation or matsof filamentous algaeor in mud-sand,fine sand, or sand-siltsubstrata. Figure22. Shellof Ischadiumrecurvum Remarks:Dali's marshclams, often very abundantin brackish rnarshes,are often overlookedbecause of their smallsize. As a result,little is known abouttheir biology,Externally they resemblethe equallysmall freshwater "pill clams" of the family Sphaeriidae. In fact, like the "pill clams,"C. floridana broodsits young,releasing them as young juveniles. Dali's marsh clams have also been confused with juveniles of the Carolina marsh clam P. caroliniana. Juvenile Carolina marsh clams have thicker shells,a thick, well-develop- Figure 23. Shellof Amygdalumpapyrium ed periostracum,and distinctly different hinge teeth three cardinals and a well-developed posterior lat- eral!. Dali's marsh clam has been reported previously Family Cyrenoididae from brackish waters in Delaware, Georgia, southern Cyrenoidafloridana Dali, 1896 Florida, and Mississippi.I havecollected C. floridana Figure 24 from tidal marshes near Tuckahoe, New Jersey; Beau- fort, North Carolina; and Lake Pontchartrain, Louisi- ana. My New Jersey and Louisiana collections are northern and westernrange extensions for C. flori- dana. Often the interior of the shells of Cyrenoida are coveredwith igloo-like bumps. These bumps, which can be seenin a photographof C.floridana in Abbott 974!, arecaused by the larvaeof trematode flatworm! parasites.The trematodes,after settling on the innersurface of the shell,become partially sur- roundedwith mother-of-pearl,produced by the clam. The infectedclams are then eatenby marshbirds and raccoons,and the adult trematodesdevelop in the in- testina! tracts of these animals. The life histories of this trematodeand severalother parasitesof Cyre- noida are currently beingstudied by the author and R, M, Overstreet. References:Abbott 974!; Leathern et al. 976!.

I'amily Solecurtidae Figure26. Commonoyster Crassostrea virginica. Tagelusplebius Solander, 1786! Figure 25 Family Ostreidae Crassostreavirginica Gmelin, 1791! Common Name; Stout Tagelus;Stout Razor Clam Synonym: Tagelusgibbus Figures 26,27 RecognitionCharacters: Valves elongate, equal, rec- tangular,with endsgaping when closed;hinges with Common Name: Eastern Oyster; American Oyster cardinal teeth present,laterals absent;living speci- Recognition Characters: Shell reaching over 150 mm mens with well-developed,elongate siphons; shells in length, irregularly shapeddepending on growth reachinglengths of over 10 cm, conditions; attached to hard objects at umbo; often Distribution: Atlantic and Gulf coasts of North occurring in clumps of severalindividuals; outer edges America from CapeCod to Texas. of valvesthin, fragile, sharp;single, large, adductor Habitat: Mesohaline bays in fine sand and mud sub- muscle, scar conspicuous,dark purple. strata; subtidal to lower intertidal,

Figure 25. Shell of Tagelusplebius.

Remarks: Stout razor clams are often common in mud banks along the edgesof Gulf salt marshes.I have collected them buried among the roots of Spartina alterniflora in the lower intertidal zone. These distinctive bivalvesare deep burrowers;how- ever, they are preyed upon by blue crabs and oc- casionallyby largefishes such as rays and drum. Figure 27. Commonoysters in the edgeof a Spartina References: Abbott 974!; Andrews 977!. marsh. 25

Figure28. Representations ofactual sizes forsome tidal marsh mollusks: a hydrobiid snails,Sayella sp., Assimineasuccinea; b Littorinairrorata; c Ceritbidea pliculosa; d C.scalarif'orrnis; e C. costata; f Detraciaflloridana; g iWelampus bidentatus; h M, coffeus; i Neritina usnea; j Cyrenoidea flor- idana;k Polymesodarnaritirna; l P. caroliniana; m 'eukensia demissa; n Rangia cuneata.

Distribution: Atlantic and Gulf coasts of North America from Gulf of St. Lawrenceto Mexico in- troduced into west coast of United States!. PHYLUM ARTHROPODA Habitat: Mesohaline;subtidal to lower intertidal; attached cemented! to hard substrata i.e., other The membersof this phylumare characterized oysters,wood, rocks!, by a jointed,chitinous exoskeleton, Thearthropods Remarks: In the northern Gulf of Mexico the eastern area highlyadaptive group, and, of the millionor oysterusually occurs in subtidalareas or onthe lower moreanimal species described, over 'i4 belong to this intertidal banks of mesohaline bays and bayous, phylum.The phylum Arthropoda isdivided into four Occasionallypopulations extend into the edgesof distinctsubphyla: Trilobitornorpha, Chelicerata, Uni- Spartinamarshes. Oysters have a largenumber of ramia and Crustacea.The subphylumTrilobito- associatedepifaunal invertebrates,including oyster rnorpha,which is generally considered themost prim- drills, barnacles,rnussels, polychaetes, and xanthid itive arthropodgroup, contains the fossiltrilobites, crabs, Sotnc of the speciesassociated with oysters Thesubphylum Chelicerata, which is characterized by areincluded in thisguide; however, a discussionof all claw-likefeeding structures chelicerae! and no anten- the associated invertebrates of tidal marsh oyster nae,contains the classesMerostomata horseshoe populationswould be far too lengthy to includehere, crabs!,Pycnogonida sea spiders! and Arachnida Because of its economic importance as a sea scorpions,spiders, mites, ticks!. The subphylum Uni- food, the eastern oyster has been one of the most ramiahas five classes,including the Insecta = Hexa- intensivelystudied mollusks in the world, In addition poda!,Chilopoda centipedes! andDiplopoda milli- to its food value, the commercial use of the dead pedes!,and is characterizedby having uniramus ap- shellsof oystersis alsoa multi-milliondollar industry. pendagesanda singlepair of antennae.Thesubphyl- I or further information and references, the reader is um Crustaceacontains eight classesand far more referred to works by Galtsoff and Joyce, marinespecies than any other arthropod group; it is References: Galtsoff 964!; Joyce 972!; Wells characterizedby the presence of biramusappendages and two pairs of antennae, 961!. 26 The class Insecta =Hexapoda!is by far the ClassCirrepnlia largestgroup of arthropods.Several hundred species of insectshave been reported from tidal rnarshesin Commonlycalled barnacles,the membersof this the southeastern United States. Insects are not treat- classare free-living sessile forms or parasites.There are ed in this guide sincethey are consideredmore or over800 describedspecies contained within five orders less terrestrial forms. It should be noted that the lar- twofree-living and three parasitic!. Many species are vae of severalgroups of insects,such as the chiron- hermaphroditicwhile the others are diecious sexes sep- omid midges,tabanid flies, and dragonfliesare often arate!.Barnacles have two types of planktoniclarvae, common in tidal marsh pools or sediment and are thefeeding nauplius type and the non-feeding cypris therefore often collected with other marsh inverte- type.There are six naupli stages or instarsfollowed by brates. thecypris orsettling stage, The cypris leaves the plank- Along the Atlantic and Gulf coasts,the class tonand attaches to a suitablesubstratum or hostwhere Merostornatais representedby a singlespecies, the it metamorphosesinto a youngbarnacle. horseshoecrab, Limulus polyphemus L., 1758!. Order Thoracica Horseshoecrabs usually inhabit shallow, open coast- Suborder Balan<>morpha al waters,but they occasionallyfeed on mollusksand polychaeteworms along or on theedges of tidal mar- 'I'hc membersof' this suborderarc sessile.They shesnear the open Gulf. The sea spiders Class Pycno- havea volcano-shapedshell composed of intcrlockirlg gonida!are generally a highsalinity, epifaunal group side platpcrcular plates a pair of turgalplates Aquatic mites occur in salt marshpools and ponds, and a p;ur of scutalplates!. This group of barnaclesis but becauseof their smallsize they usuallyare in- not<>riousf<>r bne of the mostcomm<>n fouling cludedwith meiofauna,As in the caseof the insects, organisms on ship bottoms, and much research has spiders occurring in tidal marshes are not treated in been done on their control. They feed with their this guide. thoracic appendages,which arc highly modif'icd for filtering I.'oodfrom the water. One spccics,Chtha- Subphylum Crustacea malus fragilis Darwin, 1854, is ofter> common within high salinity tidal marshes. In Gulf tidal marshcs, crustaceans are the domin- ant aquatic and suld be beyond the scopeof this guide.IVith the exceptionof the bar- Recognition Characters: Shell low, relatively small, nacles, the groups treated here belong to the sub- fragile; shell wall with end plates rostrum and carina! class Malacostraca,which includes the larger and overlapped by adjacent plates. more highly advanced crustaceans. Distribution: Atlantic and Gulf coasts of' North Amer- In ger>eral,the presenceof' two pairs of antcrlna ica from Massachusetts to 'I'exas. <>r"feelers" on crustaceansseparates them from other Habitat: Upper intertidal on Spartina alternrflora arthropodgroups that haveonly a singlepair. In add- stalks, pilings, and rock jetties on or near to the <>pen ition to an extra pair of antennae,they have more Gulf in salinities greater than 15%o. than six legs,which distinguishesthem from the in- Remarks: This species is common on the stalks of sects.Many aquaticand semiaquaticcrustace,rrrs also marsh grass S. alterniflora! in the high salinity arnic larval stages. The primitive nauplius of northwestern Florida. It appears to be less com- larva is unique to the Crustacea.The other crustacean mon in Alabama, Mississippi,and Louisiana marshes larval types will be discussedunder the groups in where salinities are generally much lower. which they occur, It should be mentioned that some Two other species of balanomorph barnacles, authoritiesbelieve that severalgroups of arthropods, Balanus. eburneus Gould, 184I, all@I II. subalbidus includingthe Crustacea,should be split into different Henry, 1973, occasionally occur attached to oyster phyla. Moore 969! considered the Crustacea to be shells, tree srumps, bridge pilings, and other harcf sub- a subphylum composed of eight distinct classes,in- strata along or on thc cdgcs of tidal marshes. The cludingthe barnacles Class Cirripedia! and the higher genus Balanus dil'fers from Chtharnaius by having crustaceans Class Malacostraca!. This classification is larger, thicker, and higher shells with <>nlyon< cnd followed here. plate carina! overlappedby adjacent plates Fig. A!. 27 When Balanus eburneus, a mesohaline species, occurs proximately25 extant speciesbelonging to threegen- in lidal marshes,it is usually f'ound attached to the era, none of which are associatedwith northern Gulf shell of the eastern oyster, C. virginica Balanus tidal marshes. subalbidus, which was long confused with II, irnpro- vrsus, tolerates low salinities and appears to be the Superorder Peracarida only barnaclein the northern Gulf that can live in oligohaline waters. It often occurs on exposed tree Peracaridansbr<>ud their y<>ungin pouches form- roots, dead wood, pilings and other hard substrata ed by outgrowths from the basesof the thoracic legs. adjacentto low salinity tidal marshes. The pouch is called a marsupium,and th<:plate-like References: Dando and Southward 980!; Henry outgrowths of which it is composedare called oosteg- andMcLaughlin976!; Poirrierand Partridge979!. ites or brood plates. Over 20 speciesof peracaridans have been found associated with tidal marshes in the northern Gulf. Severalorders arc included within the Superord- l/' er Peracarida, five of which Mysidacea, Cumacea, Tanaidacea,Isopoda and Amphipuda! are represent- ed in estuarine and tidal marsh habitats of the north- ern Gulf, 'I'here is considerable variation in the body f'orm and shapeamong the orders,as well aswithin each order. With the exception<>f cumaceans, peracaridans characteristicallyhave a singlepair of maxillipeds.

Order Mysidacea

Mysidsare small, shrimp-like peracaridans. Most members of the order are marine forms; however, a numberof speciesare known from brackish and fresh waters.The shallowwater speciesbelong to the fam- ily Mysidae.The presenceof sevenpairs of biramus legs,a broodpouch, and a statocyston theinner Figure 29, Chtharnalusfragilis. a closeup view of ramusof theuropod distinguish the FamilyMysidae barnacles on stem and leaf of 5partina alterniflora; fromthe "trueshrimps" of theOrder Decapoda. The b -- stalk of S>',alterniflora with barnacles. shrimp-likebody and stalked eyes separate mysids from the other commonperacaridans tanaids, cum- aceans,isopods, and amphipods!. Six mysidspecies Class Malacostraca occurin watersadjacent to tidalmarsh habitats in the northern Gulf of Mexico. Class Malacostraca contains the most evolution- arily advanced crustaceans and the largest number of describedspecies over 20,000!, Its members include Family Mysidae the mysid shrimps, cumaeeans, tanaids, isopods, Taphro lysislouisianae Banner, 1953 amphipods, dccapods, and a number of other smaller Figure 30 f and lesser-knowngroups. The malacostracansare di- vided into two subclasses the Phyllocarida a small, RecognitionCharacters: Anterior marginof carapace exclusivelymarine group containing a singleorder, bearingspine like projectionjust beh>wlevel of eye- the Leptostraca!and Eumalacostraca,.The eumala- stalk; distal end of tels<>ncleft or notched,bearing 40 costracanshave eight pairs of thoracic appendages; or morc smallspines; lateral margins with 10 or more huweve>, in most. members of this group one t<>three spines. pairs <>fthese thoracic limbs arc modifiedinto m«uth Distribution: N«rthern Gulf «f Mexico from Appal- parts calledmaxillipcds, IIembers <>fthis subclass achicola, I'lorida, t<>Galveston, Texas. makeup an important part of the tidal marshfauna. Habitat: In freshwaterand oligohaline low salinity! Members of the subclassPhyllocarida are character- hahitats: tlrainage ditches lower coastalplains of ized by having eight abdominalsegments, bivalved Louisiana and Texas!, mouths or rivers, upper parts carapaceand hinged rostrum. The subclasshas ap- of baysand estuaries,low salinity tidal marshpools. 28 Remarks: This form is most common in freshwater atoms, and copepods in southern Florida waters. It and low salinity areasof Louisiana and easternTexas. occurs in tidal water adjacent to marshes and may li is nut a common species in marsh habitats but is forage amongthe stalksof marshplants during high occasionally taken from marsh tidal pools adjacent tides. tu h>w salinity waters. References:Brattegard 970!; Ogleand Price976!; References: Banner 953!; Stuck, Perry, and Heard Odum and Heald 972!; Price 978!; Price a»d Vo- 979 a.,b!. dopich979!; Stuck,Perry and Heard979 a, b!.

Mysidopsis bahia Molenock, 1969 Tapbromysisbou>mani Baccscu, 1961 Figurc 30 b Figure 30 e

Recognition Characters: Anterior margin of carapace Recognition Characters: 'I'clson entire with four to lacking spine-like prnjeciinn below level of eye-stalk; five pairs of iermin;il seta» ahrupily i»creasing in distal end of tclson broadly cleft ornotched, bearing Iengih iu the mid-linc; inner ramus <>Iurupod with 35 or less spines; laicyst. spines. Distribution: Gulf Cnast I'r<>msouther» Florida I'.vcr- Distribution: Southern Florida Fverglades!to Texas. glades!to Mcxi co San G erunimo!, Habitat: Most common in lower salinit'ies but can oc- Habitat: Bays and estuaries; usually medhur> ra»ge cur over a wide range%%uo<> to 30%%u<<>!; occurring spor- salinities 8 to 25%%ufo!. adically in tidal creeks,bayous and tidal marsh ponds. Remarks: This speciesis similar tu M. almyra in si~e Remarks: During 1975 and 1976, I culleci.<>d larg» and <>v»railmorph<>logy, bui app;»tlyn<.»urs in numbersnf this speciesfrom a shalluwtidal pond ad- higher saIinitics, Like M. alrnyra, it occurs adjacent tu jacent to the southwestend uf th» Dest»d may be collected >mong marsh Highway98!. Al this locality, specimenswerc collect- plants Juncus nr .Spartina!during high tides. ed amongthc submergedstalks and roots <>iSpartina References: Price 978!; Si.uck, Verrv and Hearinl'urmatiun on the diet of this species in the northern Gulf is available; however, in the I'Iurida Bozvmaniellaspp. F.v<.rgladesthe specieshas been reportedt.u feed nn Figure 30 d detritus and, to a lesserexient, on diat<>msand cope- pods. Recognition Characters: Distal end nf tcls<>ncleli. or Rc«.>nt studies indicate that 1', bou>mani may in- notched, bearing twu large spines laierally anm these areas uI'ten had a mixture uropod with 6 tu 8 spines al<>nginner edge. of characters of boih species. Habitat: Bays, estuaries,and shall<>wwaters adjacent References: Bacescu 961!; Brattegard 969!; tn beaches; usually associatedwith sandy substrata; Compton and Price 979!; Stuck, Perry and Heard foundover a widerange of salinities/o to 30/oo!. 979 z, b!. Remarks: Tw<>species of Bozumaniellaare I'uu»d in estuarine waicrs <>fthis area, 13.floridana liolmqucst, Mysidopsisalmyra Bowman, 1964 19 75 and B. brasilinsis B acescu, 1 9G8. Im mature males and I'emal»s a»d ad»lt I'»males cannot, h< svever, Figure 30 a, c bc reliably separated.Mature males can only be sep- Recognition Characters: Telsun entire without arated hy ih» detailed s r>«iur<.. <>I' ihc rnirl.Stuck, I'crry and Ileard 979a! havediscussed graduallyincreasing in length to the mid-line; inner their separationi» d»tail a»<1haie ilh>st>at«Ithe mal» ramus of uropod with <.'yst. ihirn: U.S.A. - n<>rthcasiern Florida to Texas; References; Stuck, Perry anti Heard 979 <,b i nnrthcastcrn Mexico. Order Tanaidacea 'I'anaids! Ilabitat: Low to medium salinities /<>o to 25/ao; oli- gohalineto lower mesohzline!;estuaries, tidal rivers, 'I'he order 'I anaida<»a cu»iains appr<>ximately and tidal marsh creeks. Remarks:M. almyra is an important food organism 400 describedspecies. At onc time, becauseof a num- ber <>fsimilar tnorphological characteristics, the ian- for estuarine fishes and has been reported as a pos- sible food for commercial shrimp. Like Tapbromysis aids were listed undmani,it hasbeen reported to feedon detr'itus,di- group of the Order Isnpuda. The bodies ol' both tan- 29

Figure30. Mysidacea. a Mysidopsis almyra,lateral aspect ofgravid female; b-ftelsons; b Mysidopsis bahia-c M almyrad BotJmaniellasp.;e Taphromysisbow>mani; f T. louisianae. aidsand isopodsgenerally have flattened dorsal and Synonyms:Leptochelia ra@ax Harger, 1879 ventralb<>dy surfaces, seven pairs of legs,and onc pair Zeptocheliasp. of Odum and Heald <>Iur<>p<>- Zeptocheliadubia in Gulf of Mexico! pods by the fusi<>nol th<. I'irst two body segments RecognitionCharacters: Small up to 7mm!with glos- thoracic somitcs!,forming a smallcarapace to which sy,cream-white body; second leg not highly modified the first pair of legsis attaclted.Thus, tanaids have six for digging;males have very large cl<>ngatc < laws che- Ir<.< h<>racicsegments having a pair <>flegs, whereas lae!;lacking multi-articulate accessory flagella on first isopodshave seven free body segments bearing legs. and second antenna. Anotherstriking difference between the two orders Distribution: Atlantic and Gulf coasts of North is that in tanaidsthe first legsare chelate, whereas in America from Massachusettsto Texas; Bermuda. isopodsthey arenearly always simple or subchelate. Habitat: Muddy or silty bottoms of estuarinesystems The tanaidswere formerly called"Chclifera" because rich in organim they possessedchelatc first legs.Another difference nearlyfresh water at the mouthsof riversto hypersa- betweenthe isopodsand tanaidsis the site of respir- line conditions0%a! in marshtide poolsduring dry ation carapacein tanaids;pleopods in isopods!. periods in the summer. 'I'anaids are most common in the high salinity Remarks:llargeria rapax, which in U.S. watershas waters <>Ithe ocean; h<>wever,tw<> sp« -ics are known been often confused with Leptochelia duhia Kroycr, from tidal marshcs of the northern Gulf <>f >llexico. is often very abundantin the wetterparts of tidal One ol' these specieslives in tubes, and the other bur- marshcson the Gulf Coast. Using its own mucous, it r<>ws into thc substratum. constructs smail tubes <>fsilt and <>rganicdetritus. The tubes are attached to the roots of marsh plants, Family Paratanaidac to decayingplant matter,or evento tubesbuilt by Hargeriarapax Harger,1879! other salt marsh invertebrates such as Corophium Figure 31 louisianum and Hobsoniaflorida. 30

Figure 31. Hargeriarapax, a lateralview of adult male, b anteriorpart of femaleprotruding from her tube. The presenceof Hargeria in a marsh tide pool Synonym: Apseudessp. Subrhhmanyam,kruczynski, can often be determined by disturbing the bottom of and Drake 976!. the poo!. If small, white, elongate crustaceansappear RecognitionCharacters: Body grayish and very setose; on the pool's surface, they are probably Hargerur. first antennae with distinct accessory flagellum; sec- These creaturesare "non-wettable;" that is, they have ond leg broa<><>ts<>fjuncus in tidal mar- marsh and estuarine environments, It feeds on di- shes Florida!, usually where salinitics are higher than atoms, detritus, and fine organic particles. Hargeria 10%a . rapax is commonly eaten by tidal marsh killifishes Remarks: This species has not yet been reported from Fundulus spp.! and many other adult and juvenile the coasts of Alabama, Mississippi, <>rI.ouisiana, but cs tuarine fishes. its distribution probably extends int<> this region The adult malesof H. rapax may not feed or where suitable habitats occur. Based on my observ- molt at all andmay die soon after breeding. Males af- ations of this species in Florida tidaI marshes, the ter molting into the large-clawed,adult stagehave m<>stlikely places to look for it on the northern Gulf greatlyreduced mouth parts which appear to benon- w<>ulrl hc the Juncus marshes on the mainland side of functional.Adult malesalso havebetter developed the offshore islands. Halmyrapseudesis usually col- pleopods swimmerets! than females. The better de- lected by careful sieving <>f'the substrata around the velopedpleopods are thought to aidmales during pro- roots of the salt marsh vegetation. Information on the longedswimming excursions when they activelyseek biology of this species from northwestern Florida will out females with which to mate, More research and be presented by J. Sieg et al, in a forthcoming publi- studyon the naturalhistory of H. rapaxis necessary cation. to fully understandits apparentlycomplex life cycle References: Bacescuand Gutu 974!; Subrahman- and ecology. yam et al. 976!. References: Boesch and Diaz 974!; Larig 973!; Order Cumacea Odum and Heald 972!; Richardson 905!. Members of this order of peracaridans,which Family Apseudidae contains approximately 800 describedspecies, are us- Halmyrapseudesbahamensis Bacescu and Gutu, 1974 ually oceanic;however, many species are known from ! estuarine habitats, Cumaceanshave a very distinctive Figure 32 31

mm Figure32. Halmyrapseudes bahamensis. a first leg of female; b lateralview of male. body Iorm. '1'hccarapace appears inflated, and the froma Iowsalinity tidal marsh in NewEngland and is abdomenis elongateand narrow. Cumaccanshave a currentlyknown from Massachusetts to Virginia. Al- singlep;ur»f' uropodsand, in somefamilies, a telson. myracumasp.is smallerthan A. proximoculi.Thc 'I'he eyes,if present,are sinall and located medially malest>f A sp.have well-developed lateral expansions near the front »I the carapace. on theircarapaces; in the males of A. proximoculi Cumaceadiffer from otherperacaridans by hav- thesestructures are reduced and not well developed, ingonly I'ivc pairs of legs instead»f the usual seven Verylittle is knownabout the biol»gy of thenew pairsthat are characteristic ot tanaids, mysids, iso- speciesfrom the northern Gulf. Almyracuma sp.is pods,and amphipods, ln the Cuinacea thefirst three currentlybeing described and named, pairsol' thoraciclegs have become modified into A secondcumacean species, Oxyurostylis smi- mouthparts maxillipcds!. This condition isalso char- thi Caiman,1912, possibly could be collected in large acteristicof thehigher crustaceans of the Order Deca- tidalpools or creeksin or nearsalt marshes in high poda crabs and shrimps!, but this is only a singlesu- salinityareas c>n the offshore islands. Oxyurostylis peri'icialresemblance, andthe tw<>orders arc very smithihas a pointedtelson, distinguishing it from Al- differentmorphologically and not relatedto each myracurna,which lacks a telson. other. One species,an undescribedspecies of Almyra- References:Caiman 912!; Jonesand Burbanck cuma, occurs in tidal marsh areasof the northern 959!. Gulf.

Family Nannasticidae Almyracuma sp. Figure 33

RecognitionCharacters:without telson;pair ol' lateral expansions,<>r keels, on carapaceof males,absent on I'cmalcs; inner ramus of uropod uniarticulate with one joint!; both malesand femaleswith pair of ex»- podites<>n third inaxilliped,and first andsecond legs. Distribution:Gulf of' Mexico from Florida St. Marks! to Louisiana. Habitat: Fresh to brackish water tidal rivers, creeks, and marshpools; most commonly on silty bottoms with organicdetritus; at night of'tcn leavingbottom and becoming part of plankton. Remarks:Almyracuma sp. from the Gull' Coast is very similarto Alrnyracumaproximoculi Jones and Burbanck,1959, the only other speciesbelonging to Figure 33. Alymyracumasp. a feniale,lateral the genus.Almyracuma proximoculi was described aspect;b inale,dorsal aspect, 32 Order Isopoda Isopods!

The Isopoda, which now numbers over 4,000 described species, is considered by some carciuolo- gists to be the most phylogenetically advanced order of peracaridans. Isopods resemble tan aids and, in some respects, amphipods. They differ from tanaids by usually lacking chelate first legs and having seven rather than six free thoracic segments. A single pair of uropods and five pairs of pleopods distinguish iso- pods from amphipods, which have three pairs of pleo- pods and usually three pairs of uropods, In general, isopods have dorso-ventrally flattened bodies where- as, arnphipods have laterally compressed bodies; how- ever, exceptions exist e.g. Cyathura!, Although the majority of isopod species are mar- ine and estuarine, the group is well represented in freshwater and terrestrial habitats. The freshwater speciesare largely representedby a single family, the Asellidae, two members of which occur in brackish marshes along the northern Gulf. Some terrestrial forms, belonging to the suborder Oniscoidea and of- ten referred to as "sowbugs", "pillbugs", "sea roach- es", and "roly-polies", occur along the edgesof tidal marshes in the supratidal zone These terrestrial forms, beyond the scopeof this guide, are not treated here. I have collected or found reports of only eight speciesof isopods in tidal marshesalong the north- eastern Gulf coast, A'dotea cf. rnontosa Stimpson, Figure 34. Cyathurapo6ta, dorsalaspect. 1853!, an estuarine speciescommon in shallow meso- haline waters adjacent to the tidal marshes,is includ- work of W. D. Burbank and his students. Recent stud- ed in the Key since it might occasionally occur in ies by other scientists on C. polita populations occurr- tidal marsh pools. ing in Juncus tidal marshes on northwestern Florida indicated a two-year life cycle. Juveniles mature dur- Family Anthuridae Anthurids! ing thc spring after approximately one year of devel- Cyathura polita Stimpson, 1855 opment. Often, mature femalestransform into males, a condition technically described as "protogynic." Figure 34 Cyathura polita often occurs in large numbers and forms an important part of the food web in many es- Recognition Characters: Body vermiform worm-like!, tuaries. elongate over 7 times longer than wide!, cylindrical, References:Burbanck 967!; Frankenburg and Bur- reaching $5mm in length usually smaller on Gulf banck 963!; Kruczynski and Subrahmanyam coast than on Atlantic coast!; first pair of legs 978!; Miller and Burbanck 961!, strongly subchelate; dorsal surface of head and thorax smooth with light blotches of dark gray pigment; an- Family Sphaeromidae Sphaeromids! tennae short; antenna 2 longer than antenna I; an- tenna 1 approximately equal in length to cephalon Cassidinideaovalis Say, 1818! head!; first 5 abdominal segments completely fused; Figure 35 sixth abdominal segment reduced, fused with telson. Distribution: Atlantic and Gulf coasts of North Synonym: Cassidinidealunifrons Richardson, 1900! America from Maine to Louisiana. Recognition Characters: Body small, reaching 3 to Habitat: Oligohaline to rnesohaline less than 1/oo to 4 mm, rounded, flattened; cephalon distinctly nar- 20/oo!; burrows in mud to mud-sand substrata in es- rower than and recessed into first free thoracic seg- tuariesand damp areas of tidal marshes, ment; lateral margins of first free thoracic segment Remarks:'I'he biology of this commonbut secretive extending to posterior margin of pleotelson; inner marine isopod is well known because of the extensive branch of uropod well developed, extending to pos- terior margin of pleotelson;outer branchof uropod greatlyreduced, inserted into marginof inner branch. Distribution: Atlantic coast of North America from New Englandto Georgia;Gulf coastof North Amer- ica from northwestern Florida to I,ouisiana. Habitat: Oligohalincto lower mesohaline less than 1%o to 20%<>!;shallow bay bottoms on oysters and submergedvegetation; intertidally in marsh pools on fallen leavesand other plant debris. Remarks: In wet, intertidal areas of low salinity mar- shes, this littl< sphaeromid is often found flattened againstthe surfaceof leaves,wood, shells,and marsh grassstems. Because it usually matchesthe color of the surlace to which it is attached, Cassidinideaova- lis can be easily overlooked. I'<>rmany yearsCassidinidea ovalis and C. luni- frons were listed as separatespecies. The original, brief descripti<>nol' C. 1Vaesa! ovalis by Thomas Say in 1818 was based on specimensfrom the coast of South Car<>lina. IIarriet Richardson's 1900 de- Figure 35. Cassidinideaovalis, dorsal aspect. scripti<>nof C. =Cassidinia,Cassidksca! lunifrons was based on specimens from New Jersey. Richardson on outer edge, 905! indicated that the two speciesmight be the Distribution: Widely spreadthroughout subtropical same, but becauseSay's original specimenswere in andtropical seas of theworld; east and Gulf coastsof very poor condition and no additi<>naIspecimens North America from South Carolina to Texas. I'rom Sccasionallyhard-packed tz 969!, have also suggestedthat C. ovalis and C. sand substrates. lunhfronsmight be the samespecies. Based on the Remarks: Sphaerornaterebrans is not a true tidal many collccti<>nsI have made along the coastsof marsh speciesbut is included here becauseI have North Carolina, South Carolina, and Georgia, I be- found it in decayingwood alongthe edgesof low sa- lieve that only «ne speciesol Cassidinideais present linity tidal marshesof the northern Gulf. In other on thc eastern coast of North America, Since C. ova- coastal areas of southern North America and various lis Say, 1818! is the oldestavailable name, C. luni- frons 14ichardson,1900, becomes its synonym. In a recent publication, Livingston et al. 977! used the name C. ovalis I'or specimenscollected in northwest- ern Florida. References: Livingston et al. 977!; Menzies and Frankenberg966!; Richardson900, 1905!; Say 818!; Schultz 969!.

Sphaeromaterebrans Bate, 1866 E Figure 36 O CJ

Synonym: Sphaerornadestructor Richardson, 1897 Recognition Characters: Body up to 8 mm long with rounded extremities, slightly over twice as long as wide; cephalon nearly as broad as first free thoracic segment; first free thoracic segmentnot extending be- yond anterior ol eyes;last thoracic segmentwith four dorsal tubercles; abdominal segmentsand pleotelson with scvcral low but distinct tubercles; uropods ex- tending past pleotelson, outer longer with l'our teeth Figure 36. Sphaerornaterebrans, dorsal aspect. subtropical- tropical regions, this wood-burrowing specieshas been reported to causeconsiderable darn- age to wooden bridges and pier pilings. A study in southern Florida indicated that S. terebrans common- ly boresinto the roots of red rnangrovesand might have an important ecological impact on the mangrove swampsof that area.Sphaeroma destructor, described from infested dock pilings in northeast Florida, was recently considered a junior synonym of S. terebrans by Estevezand Simon 975!. Another speciesof Sphaeroma, S. quadridenta- tum Say, 1818, was reported from tidal marshesin northwestern Florida This speciesis common in Gulf 0,5mm estuaries and along open beaches where it often causesdecay in old tree stumps and pilings. Thus, like S. terebrans, it is not a true marsh species;its occur- rence in salt marshes is not common. The body of Figure 37. Munna reynoldsi.a male,dorsal aspect Sphaeromaquadridentatum lacks tubercles, easily dis- legs omitted!; b Female,dorsal aspect. a after tinguishing it from S. terebrans. Menziesand Frankenburg, 1966!. References: Estevez and Simon 975!; Behm and Humm 973!; Richardson 905!; Simberloff et al. ually <>veri<>okedbecause of its minute size. I have 978!. als<>c<>llectcd M. reynoldsi from a brackish water ditch on the cmouth Newport River in Carterette Family Munnidae County, North Carolina, a record which extends its Munna reynoldsi Frankenbergand Menzies, 1966 range northward up thc Atlantic from Georgia, 'I'he isopod, often preyed upon by salt marsh killifishes Figure 37 and other small cyprinodont fishes, I'ccds >>ndetritus Recognition Characters:Body minute, lessthan 2 mm and benthic algae, long; eyes on lateral protuberances; first antenna References: Callahan, Clark, and Robertson 977}; small, less than half the length of second antenna; Frankenbcrg and Menzies 966}; Livingston et al. second antenna about one-hall length ol' body; legs 977!; Schultz 969!. long, extending laterally from body; pleotelson long- er than wide; uropods small, inserted in lateral indent- ations near cnd of pleotelson, not cxtcnLirceus sp. from usually associated with decaying leaves, marsh grass, brackish tidal marsh pools in Mississippi Davis Bayou and wood. and Gulf Park! and Louisiana Lake Pontchartrain}. Remarks: The males and females of this little isopod Asellus obtusus and Lirceus can be distinguished are quite distinct. Females,usually larger than males, from each other by their cephalons, The cephalon of have a much larger third free thoracic segment and A. obtesus is small, narrow and unnotchep<>dsprobably originated from these fresh- son, 1977; Livingston et al., 1977!. Munna reynoldsi water habitats. It would be interesting to study how occurs commonly in Iow salinity salt marshes and well A. obtusus and Lirceus sp. can adapt to estua- bays along the coast of the northern Gulf but is us- rine conditions, Once, I collected both species from a tidal pool with a salinityof over 10%o. References; Williams 970!.

Family Bopyridae Probopyrus pandalicola Packard, 1880 Figure 40

RecognitionCharacters: Occurring in pairs,with smaIl dwarf male usually attached to pleopods of female; body of female highly modified for parasitism; para- sitic on Palaemonetespugio. Distribution: Eastern and Gulf coasts of North Amer- ica from Ncw England to Mexico. Habitat: Estuarine, parasitic in gill chamber of estu- arine grassshrimps, Palaernonetes pugio. Remarks: In some instances I have observed over 25% of adult grassshritnp from tidal marsh ponds infect- etl with Probopyrus pandalicola. Usually, however, the isopod infects less than I'k of the shrimp popu- lation. Probopyrus pandalicola has a complex life cycle involving two hosts. A female can produce 3 or more broods, each with hundreds of eggs that hatch into small, Iree-swimming larvae epi

2.0 mm

I,Q mrn 5.0 mm

Figure 40, Probopyrus pandaiicola, a dorsal as- pect of female, b ventral aspectof female with at- tached male; c dorsal aspectof male; d carapace of host shrimp showing swollen area caused by P, Figure 39. Lirceus sp., dorsal aspect, pa ndali cola. 36 shrimp, the crytoniscus moves into the gill chamber and usually have seven distinct unfused! thoracic of its host and metamorphosesinto the adult parasite. segments. Amphipods generally differ structurally The first crytoniscus larva to reach the gill chamber from isopods and other peracaridansby having three of the shrimp becomes a female, and the next to ar- pairs of uropods, three pairs of pleopods, and a rive becomes a "dwarf" male, only a t'raction of the laterally compressed body; however, some groups of size of the female. Such development and behavior amphipods have secondarily evolved cylindrical or indicate that the sex of this parasitic isopod is not dorso-ventrally flattened body f'orms. In other predetermined. The biochemical or hormonal mech- groups, one or more of the uropods are vestigial or anisms involved in the determination of the sex ol'P. absent. pandahcola and other members of the family Bopy- Ot' the four currently accepted suborders ridae is still not understood, Gammaridea, Caprellidea, Hyperidea, Ingolfiellidea!, Two other palaemonid shrimps from Gulf estu- only the gammarideans occur in tidal marshes of the aries are infected with two species of Probopyrus. northern Gulf of Mexico. The amphipod fauna asso- The freshwater grassshrimp Palaemonetespaludosus ciated with Mississippi-Alabama tidal marshes is repre- Gibhes, 1850, and the river shrimp Nacrobrachium sented by at least five different families. ohione Smith, 1874! are parasitized by Probopyrus Parhyale hazuafensis Dana, 1853! Family floridensis Richardson, 1904, and by P, bi thynis Hyalidae!, which I collected from tidal marches in Richardson, 1904, respectively, Georgiaand which hasbeen recently reported in asso- References:Anderson 975 a; 1975 b!; Beck 980 ciation with the root systemsof marsh grassesin a, b!; Overstreet 978!; Richardson 905!. Louisianaby Thomas976!, is includedin the key Appendix!, since in the future it may be found in Order Amphipoda similar marsh habitats of Mississippiand Alabama.

Amphipods comprise the largest and one of the Family Gammaridae most advanced groups of peracaridans. Since they Garnmarus rnucronatus Say, 1818 occur so commonly in marine environments and in such diversehabitats, amphipods arc called the "in- Figure 41 a sects of thc sea." Many speciesalso occur in fresh and ground water habitats,especially in Europe.Though Recognition Characters: Eyes reniform kidney- primarily aquatic, the membersof onc family, thc shaped!; first 3 segments of the abdomen pleon! Talitridae,have become adapted to living on land. with sharp, posteriorly directed dorsal processes Like the isopods, arnphipodslack a carapace mucronations!; third uropods biramus, subequal.

1.0mm Ifc,cI

Figure 41. Garnrnarusspp, a G, rnucronatus,adult male afterBousfield, 1973!; b "macromucron- ate" species;c Garnrnarussp. neartigrinus!. 37

Distribution: North America from southeastern Gammarussp. macromucronateform! in ciligohaline Canada to southern Florida; Gulf coast states; Cali- areas, Like thc "macromucronat,e" form, Gamnrarus nr. tigrinus!is alsoan undescribedspecies. Toler- fornia introduced!. Habitat:Euryhaline; in shallowbays and tidal marsh ating even lower salinitics than the pools,often associatedwith submergedvegetation, form, it can live in tidally influenced freshwater widgeongrass, turt.le grass, submerged marsh grass, regions. References:Bousficld 973!; Farrell 970!, Thomas roots, and hydrastGammarus 976!, rnucronatusis commonly found in marshtide pools during the c<>I' decaying marsh grasses in «rdcr t<> feed seconnsiderablequantities o ' de;>dmarsh grass into ramus strongly developed,extending well beyond line particulate matter. first and second uropods. In the olig<>halinercf~o»s of the upperbays and Distribution: I'.ast and Gulf coasts of North America river mouths,G. mucronatusis replacedby a closely from southern Canada to Louisiana. >elaterc str

1.0 m

Figure42, Meh'ta nitida, adult male after Bousfield, 1973!. 38 light of the recent descriptionsof I elongata, Recognition Characters: Body reaching over 8mm I longisetosa and M. intermidia, all previous records in length, gray with patches of dark pigment; eyes of M. nitida from the Gulf region should be suspect, irregularly rounded; first pair of gnathopods larger Until the distribution of these four speciesis further than second; first antenna longer than second; understood, the number of species associatedwith peduncle of second antenna well developed, over tidal marsh habitats will remain uncertain, My pre- times longer than flagellum; accessory flagellum l'iminary observations indicate that at least two on first antenna vestigial, minute, represented by a species,M, intermedia and M. longisetosa, occur in microscopic scale visible only with compound tidal marsh pools along the northern Gulf. On several microscope!; third uropod uniramus, with ramus occasions I found specimens of M intermedia in narrower and longer than peduncle; tube-dweller. water-filled burrows of fiddler crabs Uca minax!, Distribution: '4'idely distributed in tropical-sub- All four species from northern Gulf estuaries are tropical coastal areas of U.S.A.; eastern and Gulf included in the key in the appendix, coasts from North Carolina to Texas. References: Bousfield 973!; Odum and Heald Habitat: Euryhaline, less than 1/oo to over 40/oo; 972!; Sheridan 980!; Thomas 976!. in shallow bays, lagoons, tidal rivers, bayous, tide pools in marshesand mangroveswamps, Family Aoridae Remarks:Grandidierella honnieroi des commonly oc- curs in marsh tide pools where it constructs delicate Grandidierellabonnieroides Stephensen, 1948 tubesusing its own mucus, plus silt and organicde- Figure 43 tritus from surroundingsediment. These tubes usually

Figure 43. Grandidierella bonnieroides, male above! and anterior end of fernale below!. 39

Figure44. Corot/>ium spp,a-c C.louisianurn; d,e C.lacustre. d,e after Bousfield, 1973!, lie horizontallyon the surfaceof shells,wood, and RecognitionCharacters; Body dorsallyflattened, other hard substrata. G. bonnieroides is common in reaching7mm in length,gray with blotchesof dark the diet of many estuarinefishes and servesas an pigments;second antenna stout massivein male!, intermediatehost for an acanthocephalanparasite longer than first; flagellarsegments greatly reduced, Dollfusentischandleri! whose adult stage develops in fused; first segmentof first antennaol male with the Atlanticcroaker, spot, and other estuarine fishes, anteri<>rlyacute processor tooth on inner margin Thegenus Grandidierella was once considered absent in female!; in female, fourth segmentof a memberof the family Corophiidae;however, based second antenna armed with distoventral spine not in part on thc presenceof a minutevestigial accessory a tooth!; last three abdominalsegments <>f urosome flagellum<>n the I irst antenna,many authorities fused, lateral marginsupturned; tube-dweller. now consider it an aberrent member of the l'amily Distribution: Gulf coast of United States from -outh A<>ridae. Florida to Texas, References:Buchner et al. 978!; lvlyer 970!; Habitat: Furyhaline lessthan 1/<>0to over25%%u<>0! in Thomas 976!. tidal marsh pools and alongedges of ma>'shcs,rarely in open bays; within self-constructedtubes attached to shells, wood, leaves,exp«sed <>rpartially exposed Family Corophiidae roapex of tcison rounded, entire. in tubes attached to the ro<>tsof a single stalk of Distribution: North and Central America; Caribbean marsh grass.The tubes of C, louisianum are composed Is! ands. of mucus mixed with sand, silt or detritus, A closely Habitat: Freshwater in lakes, rivers, ponds. related species, Corophium lacustre Vanhoffcn, Remarks: In the northern Gulf this widely distributed 1911, replaces C. louisianum in the non-tidal marsh freshwater species often occurs with Gammarus sp. areas of Gulf estuaries e.g. dock pilings, open bay macromucronate form! and Gamrnarus sp. near bottoms!, Although they appear similar, the two tigrinus! <>n algae and other aquatic vegetation in speciescan be distinguishedeasily by comparing their tidal marsh pools where I'rcsh water or <>ligohalinc antennae. Segment onc <>f thc first antenna of male conditions prevail. Although it is supcrficiall~ similar C. louisianum has a prominent, forward-projecting, to Gammarus sp. macromucronate I'orm!, llyalella acute process Fig. 44 b! that is absent on the males azteca differs in having irregularly oval eyes, only two of C. lacustre Fig. 44 d!. A smailspine is present on mucronations on ihe abdomen, uniramus third the distoventral margin nf the fourth, or largest, uropods, and a rounded unclci't! tcIson. segtnent <>I' thc second antenna on the female C. References:Bousficld 973!; Thomas 976!. louisianum Fig. 44 c!; whereas,in the samelocation on C. lacustre, a distinct tooth is present Fig. 44 e!, Both C. louisianum and C. lacustre are important in Family Talitrida< the diets of estuarine fishes. References;Shoemaker 947!; Th<>mas976!. Membersof this group of terrestrial and semi- terrestrial speciesare often called "beach fleas," Family Hyalellidae "beach hoppers,""marsh hoppers,"or simply "hop- pers" because they jump about erratically when dis- Hyalella azteca Saussure, 1857 turbed, Species of this family have: ! a reduced Figure 45 first antenna lacking accessory flagellum and dis- tinctly shorter than the pcdunclc of the second Recognition Characters: Body reaching 8mm in antenna, ! reduced uniramus third uropods, and length, often grccn in living specimens; eyes irreg- 8! larg<.eyes adapted for nocturnal activity. inhales ularly oval; I'irst antenna shorter than second,without are usually larger than females and they have large, accessory flagellum; dorsal-p<>steriormargin oI' I'irst well-devel<>pe

Figure 45. Hyalella azteca, adult male after Bousfield, 1973!. 41

Figure46. Orchestia grillus. a adult male; b firstleg gnathopod! offemale; c secongleg gnatho- pod! of female after Bousfield,1973!.

It should be noted that a true terrestrial species, propodus!; first uropods lacking a strongly de- Talkroides topotum, known originallyfrom India, veloped spine on peduncleat base ol' rami; outer has been introduced into the coastalregions ol Louis- ratnus with lateral spineson margin. iana and iiiississippi,presumably from the port of Distribution: Atlantic coast of North America. from New Orleans, In this colorful species,the males do southern Canada to Florida, Gulf coast from western not have weIl-developedsecond gnat.hopodsand Florida to Texas, are smaller than the females. Talitroides topotum Habitat: Euryhaline; intertidal and supraintertidal is most common on hardwood forest floors under- zones of tidal marshes; under dead marsh grasses or neathleal mold; however,it occasionallymay intrude other debns, int.osupratidal zones adjacent to tidal marshes, Remarks:Orehestia grillus is the largest amphipod found in Gulf tidal marshes. This secretive creature can of'ten be found under rafts or dead marsh grasses Orchestiagrillus Bose, 1802 occurringalong the upperintert.idal zone of marshes. Figure 46 The commonmarsh hopper is a scavenge!.,feeding on detritus and decayingplant and animal matter. It Common Name: Common Marsh Hopper is eatenby shoreand marsh birds, including rails, Synonym: Orchestiapalustris Smith, 1878 plovers,willets, and seaside sparrows. Because of its Recognition Characters: Body relatively I arge, to diet,O. grillus, as well as the other tidal marsh species 18mmin length,color usuallylight grayor brown; of Orchestia,may be importantbiological agents in secondantenna approximately 3 timeslonger than the mechanical breakdown of vascular plant matter first;second gnathopod of matureadults with dactyl to detritus in the intertidal zone. reachingback less than one half length of palm References:Bousfield 973!; Thomas976!. 42 Orchestiauhleri Shoemaker,1936 well-developedspine on peduncleat base of rami; Figure 47 outer ramus lacking lateral spines. Distribution: Gulf coast of United States from south- Common Name: Uhler's Marsh Hopper ern Florida to Texas. Recognition Characters: Body reaching 18 mm Habitat: intertidal zones of marshcs;curyhaline, in length; second gnathopod of adult male with under marsh vegetation. dactyl reachingba.ck past propodus; first uropodwith Remarks: This form apparently representsa new well-developedspine on peduncle at baseof rami. species,which will bc placedalong with the closely Distribution: East and Gull' coasts of North America related O. costarica~ain a new genusin a forth- from North Carolina to Louisiana. coming publication by l',. L. Bousfield. Orchestia Habitat: Under dead and living vegetation; intertidal costaricana was described from Costa Rica. Like zone of oligohaline and mcsohaline tidal marshes, Orchestt'agrillus and O. uhleri, chelatemarsh hop- Remarks:This speciesoften occurswith 0, grillus; pers are eaten by a variety of' marsh and shore birds. however,O. uhleri is more commonin lower salinity Like O. uhleri, it is more commonin damperparts habitats, and it generallyoccupies damper areas nf of the marsh than its larger and more terrestrial the tidal marsh, relativeO. grillus, '1'hefemales nf' Orchestiasp. near Reference: Bousfield 973!. costaricana!can be dist.inguishedfrom those of O. grillus and O. uhleriby the absenceof' lateralspines Orchestiasp. nearO. costaricanaStebbing, 1906! on the outer ramusof their first urnpod. Figure 48 References:Stebbing 906!; Thomas976!.

Common Name: ChelateMarsh Hopper Orchestiaplatensis Krpyer, 1845 Recognition Characters: Body reaching 10 mm in Figure 49 length; second antenna over 4 times longer than first.; secondgnathopod of male chclatc;first uropod with CommonName: Krpyer'sBeach Hopper

Figure 47, Orchestiauhleri. a adult male; b first leg of female; c secondleg of female after Bous- field, 1973!. 43

Figure48. "Orchestia"nr.costaricana. a adult male; b secondleg of female after Bousfield, unpub- lished!.

Figure49. Orchestittplatensis. a adultmale; b first legof female;c secondleg of fernale after Bousfield, 1973!, 44 Synonyn>:Orcbestia agilis Smith, 1873 of decapods,Instead of the female incubating the Recognition Characters: Body reaching 12 mm in eggson her pleopods,the fertilizedeggs are released length; second antenna approximately 3 times longer directly into the water.A free-swimmingnauplius than first with peduncle segmentsthickened in adult larva hatchesfrom the egg and, after severalmolts, males; second gnathopod of male with dactyl metamorphosesinto a shrimp-likelarval stage called reaching hack less than one hal f length o I' palm a zoea. 'I'he z<>ca molts several more times before propodus!; first uropod with outer ramus lacking becoming a postlarva.The Pcnaeideaare the only lateral spines. group of dccap<>dcrustaceans known to have a I'rec- Distribution: Widely distributed throughcaridians,copepods, and barnacles, Habitat: I'.uryhafinc in upper intertidal and supratidal zones; under dead vegetation and other debris; I' twm- speciesof the genus Penaeusforage in tidal marshes ponent of open shore and beach comrnumties and during high fides and occasionally <>ccurtemporarily serves as an important I'ood fnds. birds. Members of thc genusPenaeus breed hl of fshvcr thc c<>ntincntal she]f'. IIere the pelagic nauplius and zoeal stages occur. The post-larvae Superorder Eucarida mi brackisli water bays where they develop Order Decapoda into juveniles. Nurtured by the rich food supplies available in the esf.uarineand adjacent.tidal-rnarshes, The Decap<>ciaare considered the mostadvanced the yw rapidly. Af'ter r group of' crustaceans.Appr<>ximately 9,000 species four months in these estuarine "nurserygrounds," are presently known. The order containsthe larger t.hey become subadults, large enough t<>be aught and better known crustaceans, such as 1<>bsters, commercially, The subadut ts migrate to offshore crayfishes,hermit crabs, shrimps, and crabs. The waters, where they mature into adults that form the decapodbody plan is generally shrimp-like Cari- breedingstock for the next year's "crop." The Gulf doid! or crab-like cancroid!. The order is character- speciesof Penaeusrarely live over one-and-a-halfto ized by the following: ! modification of the first two years. three pairs of thoracic appendagesinto mouth parts maxillipeds!; ! five pairsof legs hencethe term Penaeus aztecus Ives, 1891 "decapods"!; ! a shellor carapaceformed from the F>gure 50 b, d fusion of the head and thoracic segmcatscovering the head, thorax, and associatedcoxial gills; and ! us- Common Name: Brown Shrimp ually planktonic larval stages. Recognition Characters: T pair larval stages. of well-developed grooves cxtcl>ding on either side Over 20 difterent. species <>I recap<>dsoccur <>frostral keel to near posterior margin. in <>ralasts <>f Uniterc969j. northern S <>ut h Am erica. Habitat: Plankt<>nie larvae and ailfs in stiallff- Suborder Dendrobranchiata shore waters; post-larvaeand juveniles in estuaries. Infraorder Penaeidea Remarks: From April thr<>ugh the summer months the postlarvae and juveniles of brown shrimp often This gr<>upund the tida! marshes, Fdib! c-size the first thrcc pairsof legsbeing chclate; and ! the juveniles are present in late May and Jun<.. 'I'hcy grt<>vcrlapping those of the first, The life cycle shore waters in late June and early July. of the Dendrobranchiatadiffers from all other groups References: Farfante 969!; Williams 965!. 45

~ b-e! 2.0 t.rn ~ f! 2.Q mrn

Fi re 50. a Pevaeus setiferus;,; b c d ors salaspects of thecarapaces of Penaeus aztecus and P. seriferus, rcs i;, . d P . J' resectively dorsal aspects of last sixth!abdominal seg- mentsUropods and telsons f Palaemonetespugio,dorsal aspect of the telson and uropo a a ter Williams,1965; b, c after Farfante,1969!. 46 Penaeussetiferus L., 1767! andrails, Marsh grass shrimps are opportunistic feed- Figure 50 a, c, e ers and eat a varietyof animaland plant matter, in- cluding detritus, meiofauna, algae, ann Guff estuaries and often feenthslater than brown shrimp and thus the the transparentbodies of infectedmarsh grass shrimp. postlarvae of white shrimp arrive in the estuaries Three other speciesof grassshrimps, P. vulgaris later. Juvenile white shrimp usually become numer- Say, 1818!, P. paludosus Gibbes, 1850!, and P. ous in July and August and remain in the bays and kadurkensis Rathbun, 1902!, may also occur in the estuaries until f'all and the advent. of cold weather; vicinity of tidal marshes.Palaernonetes vulgaris Fig. then as subadults, most leave the estuaries f<>r off- 51 c, d! is distinguished from P. pugio by the follow- shore waters. ing: ! P. vulgarishas a rostrumwith teeth nearly References:Farfante f969!; Williams965!. reaching the tip; ! the palm of the second leg of the female P. vulgaris is distinctly longer than the carpus;and ! P. vulgarishas small teeth on the Suborder Pleocyemata chela of its second legs two on the movable finger Infraorder Caridea and one on the fixed finger!. Although P, pugio and P. vulgaris occasionally occur together around oyster Carideanshrimps differ from penaeidsin two reefs adjacent to the salt marshes,P. vulgaris usually ways: I! carideanshave non-chelate third legs; and is more commonly associatedwith fouling organisms ! the pleura of the second abdominal segment of barnacles, hydroids! on dock pilings and shell bot- carideans overlaps the first and third segments, Fe- toms. Palaeornonetesvulgaris is also more sensitiveto rnale carideans carry their fertilized eggs on their low salinities and usually does not occur in waters be- pie<>p<>ds,A plankt<>nic nauplius stage is absent, and low 10/<><>. zoeahatch directly from the eggs. Palaernonetespaludosus and P. kadiakensis re- place P. pugio in the freshwater tidal marshesadja- I'amily Palaemonidae Palaernonid Shrimps! cent to the mouths of rivers. All three species,how- Palaemonetespugio Holthuis, 1949 ever, may occasionally occur together in oligohaline conditions. Distinguishing characters for separating Figure 51 a these three speciesare presented in the key and illus- trated in Fig. 51 a, e, f. Common Name: Marsh GrassShrimp Another palaemonid shrimp, rWacrohrachium Recognition characters: .Tip of rostrum blade-like, ohione Smith, 1874!, may also be found with lacking spines; second legs larger than first with P. puli o in oligohaline tidal marshes,especially those chela lacking teeth; palm propodus! shorter than adjacent t<>the m<>uih<>I the Mississippi River, The carpus in female; branchiostegal spine present; juveniles of A4, ohione are similar to adult P. pugio, hepatic spine absent. but the presence of a hepatic spine and the lack Distribution: Atlantic and Gulf coasts from Massa- of a branchiostegalspine on M ohione Figure 51 g! chusetts to Texas, readily separates the two forms. Habitat: Euryhaline less than l%%uooto over 30%%uo<>!References: Holthuis 952!; Overstreet f 1978!; in bays and tidal creeks; comm<>n in shallow water Welsh 975!; Williams 965!. in or around tidal marshes, submerged vegetation, and oyster reefs. Infraorder Anornura Remarks: Palaemonetespugio is a year-r<>undresident in Gulf coast estuaries, It is eaten by many animals The anomurans comprise a morphol<>gically including estuarine fishes, blue crabs, herons, ducks diverse group of crustaceanswhich include the hermit crabs, mud shrimps, mole crabs, and porcellanid 1935, and Caltianassatrilobata Biffar, 1971, which crabs.One speciesoI' hermit crab commonlyoccurs live in deepburrows, occur in thesubstrata along the in salt rnarshesbordering open bays and largebay- edgesof tidal marshesof the northernGulf. These ous.Also, three species of mudshrimps, Upogebia af- threemud shrimpsare not discussedbelow, but are finis Say, 1818!,Callianassa jamaicense Schmitt, included within the taxonomic key,

I.O mm

Figure51, a Palaemonetespugio;b, c P,pugio and P. vulgaris, respectively, chelaeof second legs; d-g lateralaspects ofthe rostra and anterior parts ofthe carapace; d P. vuIgaris; e P. paludosus; f P.krtdiakensis; and g Nacrobrachiumohione. e, f afterHolthuis, 1952!. Family Diogenidae Diogenid Hermit Crabs! Infraorder Brachyura Crabs! Clibanariusvittatus Bose, 1801 or 1802! Figure 52 The Brachyura, or true crabs, have reduced ab- domens that lack urop<>dsand are tightly flexed un- Common Name: Striped Hermit Crab derneaththeir cephalothoraces.These features distin- Recognition Characters: Abdomen asymmetrical, guish brachyurans from thc superficially similar modified for <>ccupyinggastropod shells; chclipcds porcellanid "crabs" of the inlraurmenswith uropods. longitudinal stripes. I'<>ur fan>ilies of crabs, ><..presentedby at least 15 Distribution: Atlantic and Gulf coasts of North different species,<>cc«r on or along the «lg1 America; Central America, and South America from northern Gulf tidal marshes. Virginia to Brazil Rio de Janeiro!. Family Portunidae Swimming Crabs! Habitat: Shallow subtidal to intertidal zone; meso- haline to polyhaline 0%o to over 35%o!; common Callinectessapidus Rathbun 1896 un r<>ckjetties, protected beaches, and in salt marshcs Figures 53,54 near thc open Gulf'. Remarks:The adults and especiallythc juvcnilcs ol' Common Name: Common Blue Crab this c<>mmonhermit eral> are often present in tidal Recognition Characters: Last pair of legs with ter- marshesnear the Gulf. In salt marshes,juveniles minal segment oval and flattened, modified for swim- usually occupy stoften utilize sharp, strongly developed; four notches on frontal the shellsuf OysterDrills, Crowr>Conchs, and Moon margin between eyes; chelipeds of females and sub- Snails. 'I'hc Stripe<1I Icrmit Crab is an omnivorous adult maleswith red areaon palm. sca.vengcr. Distribution: I'.ast and Gulf coastsof N<>rthAmerica, References:Williams I!! 65!. Central America, and South America fr<>rni>>lassachu-

Figure52. Clibanariusvittatus removed from a gastropodshell, large adult life size. 49 setts to southern Brazil; Bermuda;EVestIndies, important commercialfishery. After mating and a Habitat: Euryhaline less than 1%o to more than period of feedingin the estuary,the adult females 3 5%o!; throughout all estuarineintertidal and sub- form an egg masswhich is attachedto the pleopods tidal habitats. under the abdomen. Ovigerous females are often Remarks: The blue crab is the most common large called "sponge" crabs becausetheir large egg masses estuarine crab in the northern Gulf and supports an resemble sponges.A single "sponge" crab may carry

'j»!

» «

Figure 53. Cal1inectessapidus, dorsal aspects. a adult male; b adult female.

»

"j»'!.' e '»'!

!!»l!j '!l!» s ! ».e»,l» «f l!» «k~!.,:»';' ~!ski:A~.' P~~«~» Figure 54. Cal1inectessapidus, ventral aspects. a adult,non-ovigerous female; b adult male; c- adult ovigerousfemale; d immature fernale; e immature male. 50 from 700,000 to over 2,000,000 fertilized eggs. Common Name: Common Mud Crab 1!uring the warmer months egg-bearingfemales mi- RecognitionCharacters: Major claw with well-devel- grate into the higher salinity waters around the opedtooth or tubercle!on movablefinger dactyl!; mouths of bays or just offshore where salinities fingersof clawdark; bright red spoton innersurface are optimal for hatchingof their eggsand survivalof of third maxillipedof all males, the larvae. Seven zoeal larval stages and one mega- Distribution: L'astern Atlantic and Gulf' of Mexico lopal stage an intermediate stage between thc from Massachusetts to Brazil; Bermuda. shrimp-likezoca and the first juvenilecrab stage! usu- Habitat: Bays and estuaries',mesohaline and poly- ally occur in the life cycle of C. sapidus. haline less than 10 /oo to over 35'/oo! on a variety of Blue crabs are omnivores and voracious feeders, subtidal and intertidal substrata. eating a variety of foods including detritus, snails, Remarks: Two distinct. forms of this species are oysters, clams, other crabs including their own spe- present in or adjacent to northern Gulf tidal marshes. cies!, and decaying animal matter. In tidal marshes, Simpson'smud crab, Panopeusherbstii forma simp- fiddler crabs and marsh pcriwinkles are important soni Rathbun, 1930, is predominantly an oyster as- parts of their diets, On several occasions I have ob- sociate that occurs subtidally and intertidally along served blue crabs concealed in the marsh mud in areas the edgesof salt marsheswhere oysters are present. It where fiddler crabs Uca spp.! were I'ceding, $Uhen is usually found with anotherxanthid oyster associ- a liddler crab, unaware of a blue crab's presence, ate, Eurypanopeusdepressus Smith, 1869!. Al- came too close, the blue crab quickly lifted its claws though superficiallysimilar to Simpson'smud crab, out of the mud and grabbed the unsuspecting prey. E. depressusis smaller, lacks large tubercles on the Once I saw a blue crab quickly scuttle out of the movable finger of its major claw, has a spoon-shaped water, grab a fiddler from a marshbank, and iminedi- tip on the fixed finger of the minor claw and hasa ately scuttle back into the water with its meal. Stud- red spot on the inner face of the third maxillipedof ies on the behavior of I., irrorata indicate that their both males and females. Only the malesof Simpson's movements up marsh grassstalks as the tide rises may mud crab have this red spot Fig, 55 c!. be due at least in part to an "escape" reaction to Simpson's mud crabs often excavate shallow avoid predation by blue crabs. burrows under clumps of oysters. This mud crab In addition to the blue crab, a smaller species prcys on oyster spat,young oysters,and a varietyol' of Callinectes, thc lesser blue crab C. similis Williams, other organisms. Fstuarine fishes, including the 1966, occurs around the mouths of estuaries where Gulf toadfish, red drum, and sheepshead often feed salinities are generally higher than 20/<. on Simpson'smud crabs. Occasionally juveniles of this species occur in The second form, the Obese Mud Crab, P. sandy areas along edges of Spartina marshcs of the berbstii forma obessa Smith, 1869!, which is larger outer islands. The lesser blue crab lacks rcd pigment and more darkly colored than Simpson's mud crab, on the palms of its bright blue claws and has six often builds extensive burrows and galleries unPanopeus herbstii H. Milne Edwards, 1834 pace,and like I:urypanopeusdepressus a red spot on Figures 55, 56 the third rnaxillipedof the female Fig. 56 c!, It dif- a,b 2.0 cm

Figure55. Panopeus herbstii forma simpsoni. a malemajor chela, lateral aspect; b adultmale, dorsal aspect; c inner face of female third maxilliped lacking red spot,

a

a 2.0 em ~ c! 5.0 mrn

Figure56. Panopeusberbstii forrna obessa. a malemajor chela, lateral aspect; b adultmale, dorsal aspect;c innerface of femalethird maxilliped with red spot on first segment of exopod. 52 fers from E, depressusby its much larger size, the References:Teal 959!; Williams965!, presenceof a largepronounced tooth on the movable finger of the largeclaw, and the lack of a "spoon- shapedtip" on the fixed finger of the smallclaw. Rhithropanopeusham'sii Gould, 1841! Figure 58 Furytium limosum Say, 1818! Figure 57 Common Name: Harris's Mud Crab Recognition Characters: Claws with fingers light, Common Name: White-Clawed Mud Crab nearlywhite; carapaceup to 20 mm in width, surface Recognition Characters; Carapacepurplish blue, with severaltransverse rows of granules,frontal mar- smth,reaching over 36 mm in width; chela with gin with a shallowgroove Fig. 58 c!. fingers white, cxc»pt for pink nr purple coloration Distribution; Western Atlantic and Gulf coasts from on proximal upper part of moveablelinger; lower Canada to northeast Brazil; introduced on West coast part of palm yellow or orange;first anterolateral of North America and in Europe, tooth of carapace weakly developed, flattened, Habitat: Tidal fresh water to 20%a; intertidal and coalescingwith external, orbital tooth; m<>dcrate- subtidal in mud hanks and grass ben I>ilinnthat can t!igohalinc conditions. muddy substrata of salt marshesand mangrove Ilarris's mud crab cats a variety of foods, in- swamps. cluding detritus, small crustaceans, mollusks, and de- Remarks: 'I'his colorlul and secretive mud crab caying animal matt»r. Rhithropanopeus is eaten constructsdeep vertical burrowsin tidal mud and is by severalpr»dat ncrab larval development. vorous, but little information on their feeding habits References: Costlow ct al. 966!; Odum and Heal

I,0 cm

Figure57. Eurytiumlirnosurn a malemajor chela, lateral aspect; b adultmale, dorsal aspect. 53

~~ a,b! 5,0 rnm ~ c! 2.0 mm

Figurc58. Rhithropanopeusharrisii. a malemajor chela, lateral aspect; b adultmale, dorsal aspect; c frontal margin of carapace.

Figure 59. Sesarmareticulatum, adult male. 54 Family Grapsidae Sesarmareticufatum feeds directly on living marsh plants Spartina alterniflora! and also eats fiddler Sesarmareticulatum Say, 1818! crabs, detritus, and algae. Purple marsh cr;ibs are Figure 59 consumed by some of the larger marsh predators, including blue crabs, rails, and raccoons, Ovigerous Common Name: Purple Marsh Crab females occur during the warmer months April Recognition Characters: Carapaceconvex, reaching through September!. 'I'he larval development of 28 tnm in width, with a blunt spine or tubercule S. reticulatum involves three zoeal stages and one on anterior lateral niargins, each chelae wit.h upper mcgalopal stage, inner edge of carpus having well-defined ridges of References: Abele 973!; Costlow and Bookhout tubercles running its Length; upper surface of fingers 962!; Ctichton 960, 1967!, Williams 965!. on male claws with row of several tubercles such tubcrcles indistinct or lacking in females!; Last3 art- Sesarma cinereum Bose, 1801 or 1802! icles of walking legs with thick clusters of fine, hair- Figure 60 like setae or pufiescctit. Distribution: Atlantic and Gulf coasts excluding Common Name; Wharf Crab, Friendly Crab, Square- slt lexic<> %'eraCruz!,

Figure 60. Sesarntacinereum, adult. 55

5.0 mm

Figure 61, Pachygrapsustransversus, adult,

IIahitat: Intertidal and supratidal; euryhalinc; edges Pachygrapsustransversus Gibbes, 1850! of tidal marshesand on rock jetties and docks. Figure 61 Remarl s: Square-back»dliddler crabs arc common alongthe northernGulf coast,They will foragein ter- Common Name: Mottled Shore Crab restrial areasmore than 100 yards inland from the in- RecognitionCharacters: Carapace reaching 14 mm in tertidal zone. In areas near the shore they are often width; distinctly tapering postcri<>rly,antero-lateral seen on roads, around houses, and sometimes, in margin with strongspine; distal segmentsof walking houses, which is the reason they are called "friendly legs not pubescent; carapace with numerous trans- crabs." The only other crab commonly occurring vcrs» lines. with Sesarrna cinereurn in similar terrestrial areas Distribution: Throughout tropics, North America along the northeasternGulf is the fiddler crab Uca fro>n North Car<>lina to Mexic<>. Habitat: Intertidal on or under rocks, debris, pilings; Each crab has its own shallow burrow or den, among exp<>sedmangrove and salt marsh roots; usually under plant debris or drift wood in the upper mesohalineto polyhaline 5%o to 36'!. interrsupratidal zones. Remarks: The mottled shore crab is r>ot common in Square-backed crabs arc scavengers, feeding th» northern Gulf ol Mexico; however, it and the largely on decaying animal and plant. matter. Pre- closelyrelated Pachygrapsus gracilis Saussure,1858! dators <>I S cinereurn include scasidc sparrows, are often found associated with pilings and rock raccoons, and clapper rails. jetties on or near the open Gulf. Twice I have col- I.ik» S. reti culatum, <>vigerousfemales <>I'S, lected single subadult specimens of P. transversus cinereurn occur during the warmer months; however, among the exposed roots of Spartina alterniflora there arc four zoeal stagesand one megalopal stage on the west shore of Mobile Bay Dauphin Island in thc larval devel<>pmentof S. cinereum. Causeway!.I consider its occurrencein salt marshes References: Abele 973!; Costlow and Bookhout of the northern Gulf to be sporadic and rare. 960!. References:F elder973!; Williams {1965!, 56 Family Ocypodidae Distribution: Atlantic and eastern Gulf coasts ol' North America from Massachusetts to western Flor- Ocypodid crabs,which are consideredone of rda, the morehighly evolvedand advancedgroups of deca- Habitat: Intertirlal on sand or sandy-mud substrata pods, make up an important part of the intertidal in salt marshes or open sand flats. fauna of tropical and subtropicalareas of the world. Remarks: Uca pugilator is one of the most colort'ul Along the northern Gulf two generaof this Family and well known ol thc fiddler crabs, and there have are present.One of thesegenera, Ocypode, is only been numerous studies on its ecology, behavior, and representedby a single species,the ghost crab 0, physiology. It often builds burrows in r>pen areas quadrata.Ghost crabsare found on openbeaches and along the edges of marshes. While foraging at low are not associated with tidal marshes. Members of tide, sand fiddlers aggregate into large youps or the second genus Uca, representedby at least seven "herds" containing thousands of crabs. Easily col- speciesin the northern Gulf, are commonin or ad- lected,the sandfiddler hasbecome a popularfishing jacent to tidal marshes.The malesof this genushave bait, especially for sheepsheadand for red and black one claw greatly enlarged.The male crab useshis drum. large claw in courtship and in combat againstother ln addition to waving its large claw during malesduring terrestrialdisputes. Courting males wave courtship display, the male uses it to produce a their large claws in rhythmic patterns which are rapid, drumming sound. The sound apparently is unique to each speciesof Uca, The movements caused by the claw striking either the edge <>I'the involved during waving or courtship display often carapace or the ground. During feeding, thc sand resemble fiddling movements, hence the common fiddler takes sandy material into its mouth buccal name "fiddler crab" or "fiddler" for members of the cavity! and specialized spoon-shaped setae on its genus. maxiIIipeds scour the algae and other organic matter Fiddlers are deposit feeders and scavengers, off the sandgrains. After the sandgrains have been ingesting a variety of food including detritus, nema- cleanedby the setae,the mouth partsform the grains todes, bacteria, fungi, algae, and decaying animal into "feeding balls" or "pseudo-feces"which are re- matter. The females have both their small claws adap- depositedonto the substratum.Often large concen- ted f<>rfeeding. 'I'he male cannot use his large claw trations of pseudo-fecesoccur around the openingsof for feeding, therefore, he must use the small claw the burrows of U. pugilator. much more rapidly in order to eat the same amount asa femaleduring the sameperiod of time. For many years U, pugilator was considered Fiddler crabsmake up an important part of the to be present along the entire northern Gulf; how- diet of many coastalanimals, including blue crabs, ever, in 1974, Salmon and Novak recognized a cI<>scly mud crabs, purple marsh crabs, red drum, diamond- related and morphologically similar species, back terrapins, willets, gulls, rails, herons, rice rats, U. panacea, f'rom northwestern Flr>rius reci>rds the northern Gulf of Mexico is confusing. In recent of P. pugilator west of Pensacola,Florida, are prob- years, three new species Uca panacea,U. longisig- ably referable to U, panacea, nalr's,and U. r>irens!have been describedfrom this References:Aspey 978!; Crane 975!; Hagen region, and the taxonomic validity of theseis still 980!; Heard 977!; Miller 961!; Montague 9- unsettled see Heard, 1977; Hagen, 1976, 1980!. 80!; Novak and Salmon 974!; Salmon 965!; Sal- Pendingadditional taxonomicand ecologicalstudies, mon and Atsaides 968 a, b!; Salmon et al. 978!; I tentatively recognizeseven species of Uca occuring Teal 958!; Thurman 973!; Vernberg and Costlow in tidal marsh areas of the northern Gulf of Mexico. 966!; Williams 965 a!.

Ucapugilator Bose,1802! Ucapanacea Novak and Salmon,1974 Figure 63 b Figures 62 g, h; 63 a

Common Names: Sand Fiddler Crab; Calico Fiddler Synonym: Uca pugilator for records west of RecognitionCharacters: Large claw of malewith Pensacola, Florida! inner face of palm propodus! smooth lacking Common Name: Panacea Sand Fiddler ridge of tubercles!; inner margin of carpuswith some RecognitionCharacters: Large claw with inner I'ace red pigment but not bright red!; cardiac depression of propodussmooth, lacking ridge of tubercles!and of carapace grayish brown, inner marginof carpusbright orangeto purplish-red; 57

1.0 mm h-h,m-h! h.Omm~ ;

k-I !

Figure62. Chelae a-h, k-n! andfrontal margins i, j! of Ucaspp. a, b Ucarapax; c, d U. 1ongi- signalis;e, f U.minax; g, h U.panacea; i U.rapax; j U.1ongisignalis; k, l U.speciosa; m,n U. spinicarpa. 58 cardiac depressionof' carapacerust-red. Distribution: Northern Gulf of Alexico from Florida Uca speciosa ives, 1891! panhandle to Texas, Figures 62 k, I; 63 d Habitat: Similar to that of U. pugilator. Remarks: Uca panacea is very similar to U. pugilator Recognition Characters:Carapace width up to 15mm; and even experts are hard-pressedto separate pre- large male claw delicaf.e, elongate, an species. Like color with carpus lacking distinct large tubercle on U. pugilator, U. panacea forms "feeding halls" ridge of inner margin;ridge of tubercleson inner face as a by-product of' feeding in sandy areas. Although of propodusnot distinctly raisedinto processes. there are differcnccs thc "wring" and "drumming" Distribution: Southern Florida to Mississippi; eastern courtship behavior of both speciesis basically similar. Mexico; Cuba. In addition to differences in behavior, the two species Elabitat: Mcsohaline to polyhalinc areas on sill or have different biochemical, color, and minor mor- silty sand substrata in intertidal marshes or mangrove phological characteristics. Some authorities question thickets. whether or not U. panacea should be considered Remarks: Individuals f'rom the northern Gulf p<>pula- a distinct species, and one study indicated that U. tions of Uca speciosa are generally much smaller panacea anti U. pugilator do hybridize where their than those from populations of the Florida Keys. Uca ranges <>vcrlap in northwest I'lorida. Pending addi- speciosa occurs sporadically in tidal marsheson the tional research and analysis of this taxonomic pro- offshore islands of Mississippi and Alabama, with blem, I recognize Uca panacea as a distinct species. well-established p<>pulations occuring I rom Cape References: Hagen980!; Heard 977!; Novak and San Blas southward along the western Florida coast. Salmon 974!; Powers 975!; Powers and Cole 9- In the northern Gulf, it rarely if ever occurs with 76!; Salmon et al, 978!; Thurman 973!, the similar and apparently closely related U. spini- carpa, which is usually confined to lower salinity Uca spinicarpa Rathbun, 1900 habitats. Figures 62 m, n; 63 c References: Crane 975!; Heard 977!; Salmon 967!; Thurman 97 3 !. Synonym: Uca speciosaspinicarpa Recognition Characters:Carapace width up to 23mm; Uca minax LeConte, 1855! largemale claw with inner face of propodusstrongly Figures 62 e, f; 63 h developed,raised ridges of tuberclesforming large process, carpus usually with distinct large tubercle Common I%arne: Red-jointed Fiddler Crab; Fresh- or tooth near middle of inner surface; I'rontal area water -Fiddler of carapace of both sexes often with bright green Recognition Characters: Carapace width up to 33mm; patch of pigment. front of carapace cream-white in adult; large male Distribution: Northern Gulf of Mexico from Alabama claw with tubcrcles lining inner face of palm; carpal to Texas. joints with rcd patch of pigment; mergus of second Habitat: Fresh to brackish water, intertidal banks walking leg lacking patch of dense pubescenceon and >narshes with I'irm clay, clay-sand, or clay-mud ventral margin. substratum, Distribution: Massachusetts to central eastern FI<>r- Remarks: Uca spinicarpa was recently designatedas ida; western central Florida to I ouisiana. a subspeciesof U, speciosain Crane's 975! exten- Habitat: On muddy substratain low salinity and sive monograph on the world speciesof Uca. The freshwater tidal marshes; usually <>ccuringadjacent large male claw of U, speciosa lacks the strongly to mouths of rivers, raised tuberculate ridges on thc palm and the large Remarks: Uca minax is the largest species <>f Uca tubercle on the carpus which characterize U, spini- that occurs in North America and the only species carpa, Also, U. spinicarpais distinctly larger than f'rom this region that migrates into and lives in I'resh- northern Gull specimensof U. speciosa. Becauseof watcr habitats. It withstands dessication better than these and <>therdifferences, I prefer to consider both other local speciesof Uca, and, like the friendly crab, U. spinicarpa and U. speciosaas distinct species. Sesarmacinereurn, red-jointed fiddlers often forage in Comparative studies on these two fiddler crabs are terrestrial areas a hundred or more feet inland from neededto further clarify their taxonomy. the intertidal zone, juvenile and subadult U. rninax References:Crane 975!, Felder 973!, Heard are usually brownish to brownish-gray in color and 977!. usually lack the cream-white coloration on the front G c1

e f

g h

Figure63. a Ucapanacea; b U.pugilator; c Ucaspinicarpa; d Uca speciosa; e Uca rapax, f Ucapugnax from Atlantic East Coast!; g Ucalongisignalis; h Uca minax. 60 of the carapace,which characterizesthe adult. with U. rninax and U. spinicarpa, and, in higher References: Crane 97 5!; Heard 977!; Miller salinity habitats, it occurs with U. rapax and U. 961!; Montague 980!; Teal 958!; Thurman panacea, 973!; Whiting and Meshri 974!. References: Atsaides and Salmon 968!; Crane 9- 75!; Hagen 980!; Heard 977!; Powers 975!; Ucalongisignalis Salmon and Atsaides, 1968 Thurman 974!. Figures 62 a, b, j; 63 g Uca rapax Smith, 1870! Common Name: Gulf Mud Fiddler Figures 62 c, d; 63 e Synonyms: Uca pugnax Uca rninax Synonyms: Uca virens Uca rapax longisignalis Uca pugnax virens Recognition Characters:Carapace width up to 26mm; Recognition Characters: Carapace width up to 23mm front of carapacebright greenish-blue;large male claw in northern Gulf populations; front of carapace with with low tuberculate ridge on inner I'acc of palm; bright blue pigment; large male claw with t>ib~rculate mcrus of second walking leg with patches ol dense ridge on inner face of palm; merus of second walking pubescence. leg lacking dense patch of pub cscncc on ventral Distribution: Gulf coast from central western Florida margin. to Texas. Distribution: Southern Florida; Alabama to Texas; Habitat: Mesohaline, on mud to mud-sand substrata Caribbean and Atlantic coasts of Central America and in tidal marshes. northern South America. Remarks: The taxonomic status <>fUca langisignalis Habitat: Sandy-silt substrata in mesohalinc and p<>ly- is currently muddled. Crane l975! considered this halinc salt marsh and mangrove areas, crab a subspecies of U, rapax, and, more recently, Remarks: The northern Gulf populations of Uca Hagen 980! synonymizedit with U. rninax. Uca rapax were describedas a separatespecies, Uca virens, rninax and U. longisignalis, however, have distinctly by Salmonand Atsaides968!; however,studies by different color patterns and salinity preferences, Thurman 973! and Hagen976, 1980! indicate and there are morphol<>gicaldil'ferences in thc sctac that the two species,though their color variesgreatly of the mouth parts and walking legs. Becauseof these within the range, are synonymous, I tentatively ac- and other more subtle differences, I consider U. cept the synonymyof U. virens with U. rapax, To longisgnalis to be a distinct species.Many of the pre- further clarify the taxonomyof U. rapax,living speci- vious records of Uca pugnax from the Gulf C<>ast mens from northern Gulf and Caribbean populations are referable to U. longisignalis. Uca pugnax see should be carefully comparedmorphologically and Fig. 63 f! occurs only along the Atlantic easterncoast with regard to behavior. of North America from New Fngland to central References: Crane 975!; Felder 973!; Hagen9- Fb>rida. The Gulf mud fiddler is the m~>st r<>mm<>n 80!; Heard 977!; Powers 975!; Powers and Cole spccics of fiddler in Mississippi and Alabama salt 976!; Salmon and Atsaides 969!; Tashian and marshes, In low salinity areas, it occurs sympatrically Vernberg 95 8!, 61

ACKNOWLEDGMENTS

Manypeople have helped me during the preparation of this other aspectsof its preparation.Beryl Heardcontributed to guide.Walt Brehm, Ed Cake, Darryl Felder, Paul Johnson, Joel mostaspects of this work,including the illustrationof Figs.5, Martin,Terry M«Bee, John Ogle, Robin Overstrcet, Harriet 13, 14, 21, 23, and 25; I am mostgrateful tor her patience, Perry,Ken Stuck, and Paul Wolf critically read all or partsof encouragement,and untiringhelp in this undertaking,Wanda the manuscript,and their constructivesuggestions and com- Geddieprepared Fig. 22, andE. L, Bousfieldand Harriet Perry mentsare appreciated,For variousreasons concerning tirnc, providedFigs. 48 and 54, respectively.Figure 1 and plates space,ur forniat,some of therecommendations could not be III!, XLIII!, XLV!, XLVI Ez 2!, andLXIV! were incorporatedinto the guide. redrawnor reprintedfrom E. L. Bousfield,Shallow-Water Specialthanks are due James I. Jonesand Diannc Jones of GammarideanAmphipoda nfl

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Leidenf 55:87 -96. 281 pp. I!undo,P. R. & A.J Southward.1980. A newspecies ol Chihamalu»IIall. J. R. 1973.Intraspeeific trail-I'ollowing in themarsh periwinkle 'rustaeea:Cirripcdia! «haractciized by enzymeelectrophoresis Liitorinu irroraia Say. Vehger 16;72 75. andshell inoiph<>logy; with a revisionot'other species of Chrha- Hamilt<>n,p. V, 1976.predation on Lirrorinarrrorara Mollusca malus from thc v esternshores of the Atlantic Ocean.J. Afar. Gastropoda!by Calhneeressapidus Crustacca: Portunidae!. Bhrl. Assoc. U.K. 6 !:787-831. Bull. Afar. Sei. 26!:403-409. Daniels,B. A. & R. 'I', Sawyer. 1975. The biology of thc leech . 1977. Daily in<>vementsand visual location of plant stems Atyzobdellatuguhri» ini'esting blue crabs and catfish. Bio!. Bulk by 1 Horinai irrorata Mollusca:Gastropoda!, tvtar. Behav. Physiol. Wong-tcrniin>vemcnts tivity ot coastaiwaters. ASB Bul!. 20!.147 156. of Liirorina irr;49 58, L'leuierius,I,. N 1972. 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Publ. /n>t. Afar. Sei. Univ. Tex. 2!:7 124. 62 pp. I'au«hald,K. 1977.The polychactcworms- Definitionsand keys to 1959.Capitellidae and Nereidae marine annelids! fioin the orders,families and genera.ft'vestern conchXetonyena corona Ginelin. Bull. Afar.Sei. Cuff Caribb. Gulf of Afexieo.La. StateUniv, Sca Grant Publ. I.SU SG 73 11!:45- 65. Hausman,S. A. 1936a.A c<>ntributionto the ecologyof the salt 02. 103 pp. Ffar. 6607!: and the CaribbeanSca. Srud. FaunaCuraeao Other Caribb.1st. 541-545. . 1936b. I'ood and feedingactivities of the salt maishsnail 36 29!: I I 83. . 1972. Freshwater Polyehaeres Annetidaf oftdanua! tele, 1928 o, Houston, 1 ex. 197 pp. Iirankenbcrg,D. & W. D. Burbanck.1963. A comparisonof the Gastropoda:Hydrobiidae! in the coastalwaters nf thenorthern physiologyand ecology of the estuarineis<>pod Cyarhura polita Gulf of Mexico and the taxonoinic status of Viirsealba louisianae in Massachusettsand e<>rgia.Bio!. Bull. WoodsHotej, 125 l!: Morrison,1965. Gulf Res,Rept. 6!: 309 312. & W, B, Sikora. 1972. A new speciesof Corophiun. Latreille, 81-95. I'rankenbcrg,D. & R. J. Menzies.1966. A new speciesof asellote 1806 Crustacea:Amphipoda! from Georgiabrackish waters with some ecological notes. Proc. Biol. Soc. Wash.845!:467 476, . 1951. Two new Eastern Atlantic speciesol' pulmonate mol- Henry, D, P, & P, A, McLaughlin. 1975 The barnacles ol' the Balanus lusks of the genusDerracia and two old ones family Fllobiidae!, amphlrrire coinplex Cirripedia, Throacica!. Zool. Verb. I,eiden! I. Wash,Acad. Sci 41! 17 20. 141: 3- 254. , 1953.Demonstration of the egg-massesol' De racia oridarra Holle, P. A. & C. I'. Dineen, 1957, Life history of the salt-marsh Pfeiffer!. Am. hfalacol Union Inc, Annu, Rep 6: 15. snail, hfelampus bidentarus Say. IVaurilus 70:90-95. . 1958a. Fllobiid and other ecology in Florida. IVautilus 1959, Studies on the genus hfelarnpus Pulmonara!. 71!:118-125. h aurr7ur73 l!:28 51. 1958b. The primitive [life] history of some salt inarsli Hoiliman, RhodesB. 1961. Larval Trematodesfrom the Apalachee snails, Am, Malaco!. Union Inc. Bull. I I:25 26. Bay area, Florida, with a checklist of known marine Cercariae . 1964. Notes on American Melampidac, IVaurilus 77!: arranged in a key to their superfamilies. Tularie Stud, 2oob 119 121. 9!: 1-74. Myers, A, A, 1970. Taxonomic studies on the genus Grandidrerella Holthuis, L. B. 1952, A general revision of the Palaemonidae Crus- Coutiere Crustacea: Amphipoda!, with a descnption ot G. tacea: Decapoda, Natantia! of the Americas. II. The subfamily denlimera, sp. nov. Bull. hfar. Sci, 20 l !:135 147. Palaernoninae.Allan Hancock Found. Publ. Occas. Pap No, 12: Novak, A. &. M, Salmon. 1974. Uca panacea,a new speciesof t'iddler 1-396. crab from the Gulf coast ol' the United States, Pnre Burl. Soc. Jones,N. S. & W. D, Burbanck.1959. Alrnyracumaproximoculi gen, Wash,878!:313 326. et sp. nov. Crustacea,Cumacea! from brackish water of Cape Odum, E. P, 1961. The role of tidal marshesin estuarine production. Cod, Massachusetts.Biol, Bull. WoodsHole! 116 l!:115 124. rSI.Y. Stare Conserv. June-July,12 - 15, 35, Joyce, F.. A., Jr. 1972. A partial bibliography of oysters, with anno- & A. F, Srnalley. 1959. Comparison of population energy tations. Fla. Dep. h at. Resour.Mar. Res. Lab. Spec. Sci, Rep, 34, flow of a herbivorous and a deposit feeding invertebrate in a 846 pp. salt marsh ecosystem.Proc. Xarb Acad. Sci. 45:617 622. Kraeuter, J, N. & P. L. Wolf. 1974, The relationship of marine Odurn. W. E. &. E. J. Heald. 1972, Trophic analysesof an estuarine inacroinvertebrates to salt marsh p!ants. Pp. 449 462 in Ecology mangrove cornrnumty. Bull. hfar, Sci. 22!:671 738, of Halophytes. Academic Press.Inc. Ogle, J. & W. Price. 1976. Growth of the shrimp,Penaeus azrecus, Kruczynski, W, L. &. C. B. Subrahmanyarn, 1978, Distribution and fed a diet ot'live mysids Crustacea: Mysidacea!, Gulf Res Rept breeding cycle of Cyathura pohka Isopoda: Anthuridae! in a 5!:46 47. Iuncus roemerianus marsh of northern Florida, Estuaries 1!; Oglesby, L, C. 1961. A new cercaria from an annelid. I. Parasirol. 93 100. 47!: 2 33 2 36. & S. H, Drake. 1978. Studieson the plant community of a Olrnstead, W. C. &. P, E. Fell. 1976, Tidal marsh invertebrates ot north I'lorida salt marsh. Part I, Primary production, Bull, hfar Connecticut.Conn. Arbor. Bull, 20:1 36. Sci. 28!: 316 334. Overstreet, Robin M. 1978. Marine Maladies? Worms, Cerms, and Kuenzler, E, J, 1961. Structure and energy flow of a mussel popu- Other Symbionrs from the IVorthern Gulf ofhfexico, Mississippi- lation in a Georgiasalt marsh.Limnoh Oceanogr,6:191 204. Alabarna Sea Grant Consortium, MASGP 78 021. 140 pp. Lang, K. 1973. Taxonomischeund phylogenetischeuntersuchungen Perry, H. M. 1975. 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Systematicsand distribution Institute of Marine Sciences,Morehead City, NC. 351 pp. of an estuarineisopod crustacean,Cyarhura polira Stimpson, Powers,L. W. 1975. Fiddler crabsin a nontidalenvironment. Conrrib 1855!, new comb., on the Gulf and Atlantic seaboardof the Mar, Sci. 19:67 78, United States.Biol. Bul!. WoodsHole! 120:62 84. & J, F, Cole, 1976, Temperaturevariation in fiddler crab Montague, C, L, 1980. A natural history of temperate western microhabitats.I. Exp. hfar. Bio!. Ecol. 21:141 157, Atlantic fiddler crabs GenusUca! with referenceto their impact Price, W, W, 1978. Occurrence of Mysidopsisalmyra Bowman, on the salt marsh.Contnb. Mar. Sci. 23:25 55. hf, bahia Molenock and Bowmaniellabrasiliensis Bacescu Crus- Moore, R. C. ed,!. 1969. Treariseon Invertebrate Paleontology, tacea, Mysidacea! from the eastern coast of Mexico, Gulf Res. Parr R. Anrhropoda 4. Vols. 1 and 2. Geological Society of Rept, 6!:173 175, Americaand Universityof KansasPress. & D. S. Vodopich, 1979. OccurrenceofMyridopsiralmyra Morrison, J. P. E. 1939. Two new speciesof Sayella with notes on Mysidacea, Mysidae! on the east coast of Florida, U,S.A. the genus.!s aurilus 53!;43 45. Crusraceana36!: 194 196. 65

Richardson, H. 1900. Synopsis of North Anierican invertebrates. industry andbiology of the blue crab,Callinectessapidus. JVOAA VIII. 'I'hc isapoda. A m. lVat, 34 207 230, 295 309. Tech. Rcp. IVES SSRI 640: I 94. f 90 A monographon the isopodsof North America. Tashian,R. E & F. J, Vernberg.1958. The specificdistinctness of U.S. lVatl. Mus. Bull. 54: I 717. the fiddler crabs Uca pugnax Smith! and Uca rapax Smith! at Russell-Hunter, W. D., M. L. Aplcy & R. D. Hunter. 1972. Early life- their zone of overlap in northeastern I'lorida. Zoologica 43!; historyof Melampusand the significanceof semilunarsynchrany. 89-92. Biol, Bull. Woods Hole! 143!:623 656. 'I'eal,J. M. 1958.Distribution of fiddler crabsin Georgiasalt marshes. Salmon, M. 1965. Waving display and sound production in the Ecology 39!:185 193. courtship behavior of Uca pugilator, with comparisonsto U. . 1959, Respirationof crabsin Georgiasalt marshesand its minax and U. pugnax, Zoologica 502!:123 149. relation to their ecology. Physiol. ZooL 32 l!: I 14. . 1967. Coastal distribution, display and sound production , 1962.Energy flow in the salt marshecosystein of' Georgia. by I'lorida fiddler crabs genusUca!. Anim. Behav.15:449 459. Ecology 43: 214 224, & S. P. Atsaidcs. 1968a. Behavioral, morphological and 'I'en Hove,H. A. & J, C. A Weerdenburg.1978. A generi: revision ecologicalevidence for two new speciesof fiddler crabs genus ol the brackish-water serpulid Ficopomatus Southern 1921 Uca! frain the Gait coastsaf the UnitedStates. Proc Biol. Soc. Polychaeta: Serpulinae!, including Mercierella I'auvel 1923, Wash.812!: 275 290. SphaeropomatusI'readwell 1934, MercierellopsisRioja 1945 1968h. Visual and acoustical signalling during courtship and lVeopomatusPillai 1960. Biol. Bull WoodsHole! 154: by fiddler crabs. Am. Zool. 8:623 639. 96--120, Salinon, M., G. Hyatt, K. McCarthy & J. D. Costlow, Jr. 1978, Thomas, J. D. 1976, A survey of gammarid amphipods of the Displayspecificity and reproductive isolation in the fiddlercrabs, BaratariaBay, Louisiana region, Contrib. Mar, Sci. 20:87 100. Ucapanacea and U. Pugilator.7. Tierpsychol.48:251 276. Thompson,F. G. 1968, The Aquatic Snailsof the Family Hydro- Sawyer,R. T,, A, R, Lawler&. R. M. Ovcrstreet,1975. Marine hiidae of PeninsularFlorida. Univ. of Florida Press,Gainesville, leeches of the eastern United States and the Gulf of Mexico with 26S pp. a key ta the species.J. lVat. Hist. 9!:633 667. Thurinan, C, L. 1973. Aspectsof anoxic metabolismin the fiddler Say, T. 1818. An account af the Crustaceaof the United crab Uca minax Crustacea: Decapoda! and the distribution of States. J. A cad. IVat. Sci, Phila. 1!.482 4S5. fiddler crabsaf the genusUca along the northeasterncoast of Schultz, C. A. 1969. How to know j The Marine Isopod Crustaceans. the Gulf af Mexico. M.S. thesis, University of West Florida, Win. C. Brawn Co., Pubhshcrs,I>ubuque, Iowa. 359 pp. 64 pp. Sheridan,P. F. 1980. Three new speciesof tyfelita Crustacea: Turner,R. E. 1976.Geographic variations in saltinarsh macrophyte Amphipada!with nateson the ainphipodfauna of the Apalachi- production;a review.Contrib. Mar. Sci. 20:47 68. caia estuary of Northwest Florida. IVortheast Gulf Sci 3!: Ursin, M. J. 1972. Life In and Around Salt Marshes,Thomas Y. 60- 73. Crowell Co., New York. 110 pp. Shoemaker, C, R. 1947. I'urther notes on the amphipod genus van der Schalie, H. 1933. Notes on the brackish bivalve Polymesoda Corophiurnon the east coast of America.J. Wa'sh.Acad, Sci. caroliniana Bose!. Occas.Pap. Mus. Zool. Univ, Mich. 258: I-S. 32!:47 63. Vernberg,J. F. &. J. D. Costlow,Jr. 1966. Handednessin fiddler Shuster, C. N., Jr. 1966. The Nature of a Tidal Marsh:This dynamic crabs genusUca!. Crustaceana 11!:61 64. unit of nature feeds IIsh, fowl, and animal, Information Leaflet Wass,M. L. &. T, D. Wright. 1969. CoastalWetlands of Virginia; New York State Dep. of EnvironmentalConservation, Div, of interimreport to the Governorand GeneralAssembly. Va Inst. L'd. Serv. L 145!. 8 pp. Mar. Scr.Spec, Sci. Rep. 10: I 154 pp, Simberloff, DD, J. Brawn & S. Lowrie, 1978. Isopod and insect Wells,H. W. 1961. The faunaof oysterbeds, with specialreference root borers may benefit Florida mangroves. Science201356!: to the salinity factor. Ecol, Monogr, 31:239 266. 630-632. Welsh,B. L, 1976. The role of grassshrimp, Palaemorietes pugio, in Stebbing,T. R. R. 1906. A newCirsta Rican arnphipod. Proc. U.S. a tidal marshecosystem. Ecology 56:513 530. iVat, Mus, 31490!:501- 505. Whiting,N. H. & G. A. Moshiri.1974. Certainorganism-substrate Stiven,A. E. & E, J. Kuenzler. 1979. The responseof two salt marsh relationshipsaffecting the distribution of Uca minax Crustacea: raolluscs, Littorina irrorata and Geukensiademissa, to field inan- Decapoda!.Hydrobiologia 44!:4S I 493. ipulatiansaf densityand Spartinalitter. Ecol Monogr.49!: Williams,A. B. 1965.Marine decapod crustaceans of theCarolinas. 151 171. U,S. Fish Wildl. Serv. Bur. Commer. Fish. Fish. Bull. 65 l!: Stuck, K. C., H. M. Perry & R. W, Heard. 1979a. An annotatedkey 1-298. to the Mysidaceaof the NorthCentral Gulf' of Mexico.Gulf Res. 1974. The swimming crabs of the genus Callinectes Rept. 6!:225 238. Decapoda:Portunidae!. U.S. FishWildl. Serv. Fish. Bull, 72!: . 1979b Recordsand range extensionsof Mysidaceafrom 685-798. coastaland shelf waters of the easternGulf of Mexico. Gulf Res. , 1976. The western Atlantic swimmingcrabs Callinectes Rept. 6!:239 248. ornatus, C, danae. and a new, related species Decapoda:Portu- Subiahmanyam,C. B.,W. L. Kruczynski&. S. H. Drake, 1976. Studies nidae!. TulaneStud. Zool. 13:83 93. on the animal carnrnunities in two north Florida salt rnarshes. Wilhams,G. E., III, J. J. Poff & J.T, McBee1976. Western Gulf of Part ll. Macroinvertebratecommunities. Bull. Mar, Sci. 26!: Mexico records of Stenoninereismartini Wesenberg-Lund1958 172 195. Polychaeta,Nereidae! with contributionsto its habitat ecology. Tagatz,M. E, 1968. Biologyaf the blue crab, Callinectessapidus Contrib, Mar. Sci. 20:83 85. Rathbun, in the St. Johns River, Florida, U,S, Fish Wildk Serv. Zottoli, R. 1974. Reproduction and larval development of the Fish. Bull. 67 l!:17-33. ampharetidpolychaete Amphictes fforidus. Trans. Am. Microsc. & A. B. Hall. 1971 Annotated bibliography on the fishing Soc. 93!:78 89. 66

TAXONOMIC KEYS TO SOME POLYCHAETE WORMS. MOLLUSKS, AND CRUSTACEANS FOUND ASSOCIATED WITH TIDAL MARSHES OF THE NORTHERN GULF OF MEXICO

POLYCHAETA

1 Anterior cnd with crown of radially arrangedtentacles Figs. 3i, 4!. Anterior end lacking radial crown of tentacles.

2 Living in whitecalcareous tube: stalked opercular plug present Fig. 4! . I'icr>purr>atrrsr»iarni ensis Not Jivingin calca>eoustube; operculum absent; n>inute forms, less than 5 rumlong Fig. 3i!..... Mana»unkiaspp.

3 Head andfirst 3 bodysegments lacking antennae, tentacle%, palps, and gills Fig,3b f! . Headand first 3 body segmentswith at least 1 of thesestructures Fig. 64a!..

4 Hooded hooksetae present Fig. 3c: look ot>setigers10 20!; gtlls hranchac!present or absent;body width variahle: headregion not sharplytapering to anacute point. 5 Hoodedhook setacabsent; gills dorsal,beginning hctwccn sctigcrs11 and 23. body widestbetween setigers 8 and 15; headregion tapering to anacute point Fig. 3b! '>col»plusj'ragilis

5 At leastfirst 7 setigerswith capillary sctae Fig. 3d! only Hooded hor>k sctae on son>e of the f>rst 7 sctigcrs

6 Genital setae Fig. 3e! and/or hoodedhook setaeon setigers8 and9. .Capi tella spp, First 11setigers lacking genital setae and hooded hook setae, only capillarysctac present rVvtr>mastus spp.

7 Hooded hook setae beginning on 5th setigcr. Mediomastus cf. cali forniensis Hoodedhook sctacbeginning on 6th setiger Fig. 3f!. . Heteromastusfiltfvrmts

8 Gills, perist<>mialcirri, andantennae absent; small pair of palpspresent;anteriorcnd ot'worm whitish-yellow. swollen Fig. 3a!;stout notopodial spines present in posteriorsegn>ents . ..., Paramlaliaamericana Gills, antennae,and/or peristomialcirri present;stout notopodial spinesabsent.

9 One pair of longperisto>nial cirri and I pair of equallylong gills both ofter>broken oft! on 1stand 2nd setigcrs, respectively;raised collar on dorsalsurface of 2ndsetiger Fig. 3g! . Streblospiobenedicti Fourpairs of gillsor 4 pairsof peristomialcirri present; raised collar on dorsal surface of 3rdsetigcr absent...,, 10 10 Four dorsa],transversely arranged pairs of f>nger-likegills just posteriorto head Fig. 3h!; mouthwith retractable oral tentacles;uncini present;eyes and parapodia weakly developed, antennae and jaws absent... llypaniolaflorida 1'ingcr-likegills and uncini absent;four pairsof peristomialcirri, pair of well-developedpalps, pair of' antennae present,proboscis with pair of serratejaws; eyes and parapodia well developed .. Nereidae'!l l 11 Parapodiaappearinguniramous, notopodia greatly reduced, notosetac absent Fig. 2b!,,,... JVamalycastisabiuma Parapodiadistinctly biramous, notopodia well developedwith notosetaepresent Fig. 2i, k!...... , . 1'2 12 Smallworms, less than 10 mm long;body with 34 segments;proboscis without paragnaths or papillae;dorsal cirri well developed,ft!if<>rm Fig. 2e! .. Stenoneriesmartini Adultworms reaching lengths of 50mm with over70 b<>dy segments; proboscis armed with paragnathsor papillae,. 13

13 Probosciswith dark paragnaths Fig. 2j!. Neanthes succi»ea Proboscis with tufts of finger-like papillae Fig. 2h!, Let>nereis culveri 67

MOLLUSCA

1 pelagic; 1'rceswiniming; torpedo shaped; head with large pair of eyesand 10 oral arnis tentacles! armed with suckers; shellreduced. internal I.vlliguneulabrevis Epihcnthicorbenthic; not torpedo shaped; tentacles with suckers ibsent; external calcareous shell picscnt,.....2

2 Shell consistsof two valves Figs. 17 -24! Bivalvia! 22 Shella siperculuin and gills absent; shel! conic or biconic Figs. 15, 16!. <0 Apertureusually oval, not anelongate slit; operculumand gills prese

5 Sliell with siphMelongena corona .'rovn

7 Shell elongate,about 3 tiineslonger than wide; strong

Spirewith «ld varices Fig. 10, right; Fig. 65! . Ceri thideu pliculvsa Spirelacking variccs Fig. 10, left! . Shellrcachmg only about15 nini in leiigth;axial ribs indistinct on last2 bodywhorls ,Cerithideu eostata Shellieacliing

12 1-;yeson tips

Vergewith 2 to 3 rowshe,proxiinal papilla absent Fig. t d!,...... Li t toridinops palustris

17 Concavemargin of vergewith subterminalfinger-like or keel-like process;2 subterminalpapillae on convex niargin of vergedistinctly separated from moreproximal papillae Fig. 8f, g! ., 18 Concavemargin of vergelacking finger- or keel-likeprocess; isoIatcd subterminal papillae not presenton convex marginof verge Fig.gh! .. 1'!

I 1 Subterrninalkeel-like process on concaven>argin ot verge Fig. ttf! .. Heleobopssp. torm A! Subterrninalfinger-like process on concavemargin ot verge Fig. Sg!...... IIeler>bopssp, foiii>sB;ind C!

19 Vergewith 5 to6 stalkedpapillae; aperture ot shellconstricted in adultspeciinens...... Texadinasphinciosto>na Vergewith 3 to 4 stalkedpapillae; shell glossy, translucent with apertureiiot constrictedin adultspcciinens...,, . Texadzna barretri

20 Shellbiconic, length of spirenearly one third of total shelllength, tip ot'spire often eroded Fig. 16! .. Z!etracia florzdana Shellconic, length of spireonly one fourth or lessof total shelliength

21 Whorlsof spirewith firiespiral striatioi>s Fig. 15,right! .. . Pfelanzpuscuff'cus Whorlsof spirelacking spiral striations Fig. 15,left!, . AIelanzpusbide>itatus

22 Shell with irregular marginsand surface;edges of valvesthin, fragile, anil sharp Fig. 26!;attaching to substrate,>n surfaceot' left valve:single large adductor muscle present on emptyvalves attachment of adductorinuscle inarked by darkpurple scar!. C'rassostreavirginica Shell not as describedabove; two adductor musclespresent <>neinpty valvesadductor muscle scarsdistinctly separated! .. 23 Beak umbo! terminal orsubterminal at or nearanterior end of shell!; byssal threads for attaclunent tosubstratum! presenton living specimens .. >4 Beak ceritral or subcentral; hyssal threads absent on living spccirncns,

24 Beak terminal at anterior end of shell! Beak subterir>inal.

25 Outer surfaceot' valvespurplish-gray with strong radiating ribs Fig, 22!; 3 to 4 small teeth on edgeof shell under beak;interior glossyusually with bn>wnish-purplepigment .. Ischadiunzrecur»um Outersurface of valveslight grayish-brown to tannish sometimes with zigzagnzarkings!, lacking radiating ribs Fig.21!; platformor platein interiorof shellunder beak; interior dull white, not glossy...... ,, &ytilopsisleucr>phaeata

26 Outersurface of valvessmooth Fig, 23!. glossywith yellowish-brownand greenish pign>ent... Amygdalunzpapyrium Outersurface of valvesusually dark brown with strong radiating ribs Fig.20!, beak often eroded .. Geukensiadenzissa

27 Shellelongate more than 3 timcslongerthan high!, subrectangular wizh ends gaping when valves closed Fig. 25!..... Tagelus plebi us

Shell oval or suboval less than 1.5 times longer than high! 28 Hingewith chondrophore; margins of lateralteeth serrate; shell thick, heavy; beaks widely separated from each other in adults Fig. 18! . . Rangiacuneata Hingewithout chondrophore;margins of lateralteeth lackingserrations; beaks not widely separatedfrom each other. > ! 69

29 Hingewith 2 cardinalteeth posterior tooth large, blade-like; anterior tooth small, bifed on right valve!, lateral teeth indistinct;shell thin, fragile,small usually less than 10 mm long! Fig.25!...... Cyrenoidafloridana Hingewith 3 cardinalteeth posterior tooth weakly bifed on both valves!, lateral teeth well developed; shell not fragile,more than l 0mm in length. 30 30 Shellnearly oval; periostricurn dark forming wavy, scale-like ridges Fig. 17!; beaks usually eroded in adults;interior ot shellusually white, occasionally lightly stained bluish-purple . . Poiymesoda caroliniana Shellsu boval, ot'ten wedge shaped, angular posteriorly; periostricum translucent, notforming scale-like ridges Fig. 19!; beaksnot eroded; interior of shellnearly always stained purple in varyingdegrees...... , Polymesodantaririma 70

HIGHER CRUSTACEA MALACOSTRACA!

1 Females with brood plates oostegites! for incubating eggs!arising from the basesof somethoracic legs;usually 7 pairs of legsand 1 inaxilliped except cuinaceanswhich have 5 pairs of legsand 3 maxillipeds!present; carapace, whenpresent, not coveringall thoracic segments...... Peracaridea! 2 Females without specialized brood plates; 5 pairs of thoracic legs and 3 pairs of maxillipeds present; carapace com- pletely coveringcephalothorax ...... ,... Decapod i! 36

2 Abdomen nearly as long or longer than coinbined length of head and thorax Abdomen distinctly less than half length of combined head and thorax .

3 Shrimp-like; carapace nearly covering thorax; eyes stalked, thoracic limbs all biramus; inner ranius of uropod with statocyst Figs. 30a, 67! ...... Mysidacea!6 Cephalothorax swollen; eyes sessile;abdomen and uropods narrow Fig. 33!, Cumacea! 11

4 First pair of legs chelate; thorax with 6 free segments Figs. 31, 32! . , Tanaidacea! 10 First pair of legs not chelate; thorax with 7 free segments Figs. 39, 41!.

5 Abdomen with 5 pairs of pleopods and 1 pair of uropods; body usually dorsoventrally flattened Figs. 34, 39!..., . lsopoda! 14 Abdomenwith 3 pairsof uropodsand 3 pairsof pleopods Fig. 68!; body usuallylaterally compressed...... Arnphipoda! 21

6 End of telson cleft Fig, 30d,e!, . End of telson entire, convex Fig. 30b,c!

7 Antennal scalewith lateral tooth; posteriormargin of fifth abdominalsegment with dorsalprocess Fig. 6-!...... Bowmaniella spp. floridana-brasiliensis complex! Antennalscale lacking lateral tooth; posteriormargin of fifth abdominalseginent without dorsalprocess...... 8

8 Anterior margin of carapacewith small lateral spinejust below baseof eye stalk; inner rarnusof uropod with single spine on posterior margin of statocyst,, Taphr

9 Apex of telson with 12 to 16 long spinesgradually increasing in length ruedially;inner ramusof uropod with 1 spine near statocyst ., ll fysidopsis almyra Apex of telson with 8 to 12 spinesabruptly increasingin length medially; inner ramusof uropod with 2 or niore spines near statocyst Hysidopsis bahia

10 First antennalacking distinct accessoryflagellum; secondleg not distinctly different from legs3 7; appendagesnot densely setose Fig. 31! . Hargaria rapax First antennawith well-developed,segmented, accessory flagelluin; second leg armedwith strongspines, modified for burrowing, distinctly different from legs3 7; appendagesdensely setose Fig. 32!....Halmyrapseudes bahamensis

11 Narrow pointed telson present ...... Oxyurostyhs smrthr Telson lacking. , ...,,12

12 Inner ramusof uropod a singlesegment; male with pair of lateral keelson upper part of carapace Fig. 36b!...... Almyracuma sp. Inner ramus of uropod two seginented; male lacking lateral keels on carapace ,13 71

13 Malelacking pleopods; female with dorsalkeel on third thoracicsegment, .Spiloeuma watlingi Malewith 5 pairsof pleopods;fernale without dorsal keel on third thoracicsegment Cyclaspis cf. varians 14 Uropodsterminal or subterminal,originating in posteriorthird of pleotelson . 19 Uropodsoriginating in anteriorhalf of pleotelson .15 15 Uropodsfolded under pleotelson, notvisible dorsally, forming ventral operculum overpleopods .. 2'do tea cf. montosa Uropodslateral, visible dorsally . 16 16 Bodyovate, less than 3 timeslonger than wide; uropods flattened, notextending above pleotelson,,,...... 17 Bodyelongate, approxiumatefy 7 times longer than wide; uropods partially folded and extended laterally above pleotelson Fig. 34! Cyathurapvlita 17 Eyeslocated sublaterally noton lateral margin of cephalon!onpost cephalic lobes; outer ramus ofuropod greatly reduced,inserted into nrargin of outerramus Fig, 35! Cassidinidiaovalis Eyeslocated on lateral margins ofhead; both branches of uropods well developed. 18

18 Dorsalsurface of pleotelsonsmooth Sphaernma quadri

19 Bodyminute, less than 3 mm;uropods small, not extendingbeyond distal end of pleotelson;eyes on lateral protuberances Fig.37! ltfunnarevnoldsi Bodyover 10 mm in adults;uropods extending well beyond pleotelson; eyes not on lateral protuberances. ..20 20 Headsmall, narrow, unnotched; eyes on lateral margins Fig. 38! . A sellusacutus Headrelatively large and broad with a pairof deeplateral notches; eyes not on lateral margins, located at proximal endsof cephalicnotches Fig. 39!. Lireeussp. 21 Thirduropod unirarnus Figs, 43,45,46!.. 29 Thirduropod birarnus inner ramus may be minute! Figs. 41a, 42!. 22 '22 Eyesnearly round, or irregularly shaped; inner ramus ofthird uropod minute Fig, 42!... 23 Eyeskidney-shaped; rarniof uropod3 subequal nearly same size! Fig, 41a!...... ,, Genus Gammarus!27 23 Firstantenna shorter than second antenna and lacking accessory flagellum; third uropod short, stout, not extending pastsecond uropod, larger outer ramus composed of 1 segment,subequal in length to pedunclesegment.....,... Parhyale hawaiensis Firstantenna longer than second antenna with small to 3 segmented!accessory flagellum; third uropod long, slender,extending well past second uropod over 1.5 times longer than peduncle!, larger outer ramus composed of 2 seg

24 Outerramus of uropod3 maleand fernale! with numerouslong setae., .Nelita longisetosa Outer ramusof uropod 3 lackingnumerous long setae .. .25 25 Male,antenna 2, fiagellunrwith "bottle brush" setation, peduncle segment 5 approximately equal in lengthto segment4 26 Male,antenna '2,fiagellum lacking "bottle brush" setation, peduncle segment 5 distinctly longer than segment 4.... Nelita elongata

26 Male,antenna 2, pedunclesegment 5 with bottle brush se'tae .... Nelita nitida Male,antenna 2, pedunclesegment 5 lackingbottle brush setae .Nelita intermedia 72

27 Dorsalmucronations spine! on posteriormargin of eachpleonal segment Fig. 41a,b!, 28 No dorsalmucronations on pleonalsegments oligohaline to freshwater! Fig. 41c!,...... Gammarus nr. tigvinus

Dorsalmucronations of moderatesize mesohaline! Fig. 41a! ...... Gammarusmucronatus Dorsalmucronations large, strongly developed oligohaline! Fig. 41b!.... Gammarussp, "macromucronateform"

29 Ramusof third uropod narrow, longerthan peduncle basalsegment! Fig, 43!...... Grandidierellabonneiroides Rarnusof third uropod either equalin length or shorter than peduncle Fig. 45! or broad and flattened...... 30

30 Ramus of uropod 3 broad, body flattened dorsoventrally;urosomal segmentsfused together; secondantenna of malemassive Fig. 44!; living in tubes...,,...,,...... GenusCorophiurn! 31 Ramusof uropod 3 reduced,shorter than peduncle,body laterally compressed;urosomal segments distinctly separate; secondantenna of inale not massive;not living in tubes 32

31 Male with tooth on inner margin of first pedunclesegment of first antenna Fig. 44b!; femalewith spineon disto- ventralend of pedunclesegment 4 of secondantenna Fig. 44c!.....,..., ., Corophiumlouisiunum Male without tooth on inner margin of pedunclesegment of first antenna Fig, 44d!; fernalewith tooth on disto- ventral end of pedunclesegment 4 of secondantenna Fig, 44e!. Corophium lacustre

32 Antenna 1 extending weHpast peduncleof secondantenna; dorsal posterior margin of first two pleonal segments mucronate Fig. 45!; aquatic,epibenthic, in freshand oligohalinewaters ., . Jfyaiella asteca First antennanot extendingpast peduncleof secondantenna; dorsal posterior margin of pleonal segmentssmooth not mucronate!;intertidal, semiterrestrial. ..., Talitridae! 33

33 First uropod, outer ramus lacking lateral spines Figs, 48, 49! ..34 First uropod, outer rainuswith lateral spines Figs. 46, 47! . .35

First uropod with well-developedspine betweenrami; gnathopodof male chelate;second antenna approximately 4 timeslonger than first antenna Fig, 48! . Orchestiasp. near Orchestiacostaricana! First uropod lacking well-developedspine betweenrami; gnathopodof male typically subchelate;second antenna approximately 3 times longer than first antenna Fig. 49! .. Or chestia plat ensis

35 First gnathopodof adult male with dactyl reachingback past palm; first uropod of both sexeswith well-developed spinebetween rami Fig, 47! .. Orchestiuuhleri First gnathopodof adult male with dactyl reachingback only one-half the length of palm; first uropod of both sexeslacking well-developed spine between rarni Fig. 46!. Orchestiagrillus

36 Abdomen asymmetricalor twisted, modified for living in gastropodshells; walking legswith 4 pairsof longitudinal stripes Fig. 52!.. ,.....,..., ., Clabanarius vittatus Abdomen not asymmetrical or modified for living in gastropod shells .37

37 Abdomenwell developed,not tightly flexed beneathcephalothorax; uropods present Figs, 50, 51!,...... , .. 38 Abdomenreduced, tightly flexed beneathcephalothorax; uropods absent Fig. 54a,b,d,e!...... Crabs! 47

38 Lobster-likebody form with broad telsonsand uropods living in deepburrows!; rostrum reduced,not blade-like... Mud Shrimps!39 Shrimp-likebody form with telsonsnarrow, distinctly longerthan wide; rostrum well developed,blade-like Figs. 50, 51! ...,,...,..., .. Shrimps!41

39 First legs chelatewith movablefinger dactyl! distinctly longer than fixed finger; secondlegs simple; rostrum and anterio-dorsal region of carapacewith many course stout spines; second pair of pleopods similar to following 3 pairs; body gray to grayish-brown. . Upogebiaaffinis First2 pairsof legschelate, dactyl movablefinger! of first pairnot distinctlyextending beyond fixed finger rostrum and anterio-dorsalregion of carapacesmooth; secondpair of pleopodsreduced, not similar to following 3 pairs; bodywhitish or creamaolored.. . Callianassa!40

40 Lateralmargin of telsontrilobed; ischiurn of majorchela with midventralprojection...... Callianassatrilobata Lateral marginof telsonentire, ischiumof major chelalacking midventralprojection,..., .. Callianassajamaicense

41 Third pair of legschelate; pleura of first abdominalsegment overlapping that of secondseginent; telson ending in sharppoint without terminal setae Fig. 50a,d,e!. .. Penaeidae!42 Third pair of legssimple; pleura of secondabdominal segment overlapping that of first andthird seginents;telson with terininalspines not endingin sharppoint Figs,50f, 5 la!.. ,43

42 Grooveon either sideof rostrum extendingposteriorly to nearposterior border of carapace Fig'. 50b!...,...... Penaeus azteca Grooveon either sideof rostrum not extendinginto posteriorhalf of carapace Fig. 50c! . Penaeus seri ferus

43 Hepaticspine present Fig. 50g!; mandiblewith palp Fig. 73!,, ltfacrobrachium ohione Hepaticspine absent Fig. 50d!; mandiblewithout palp .

44 Fusedpart of 2 ramiof upperantennular flagellum distinctly longer than unfusedpart; rostrum narrow with teeth irregularlyspaced . .45 Fusedpart of 2 ramiof upperantennular flagellum distinctly shorter than unfused part ,46

45 Branchiostegalspine see Fig. 70! locatedon anterior margin of carapacejust belowbranchiostegal groove Fig. 51e!... Palaemonetespaludosus Branchiostegalspine distinctly removed from anterior margin of carapaceand located soine distance below branchio- stegalgroove Fig. 5 1f!, Palaemonereskadiakensis

46 Carpusof secondleg in adult femaleshorter than palm; movable and fixed fingers of chelawith 2 and1 smallteeth, respectively,on cuttingedge; rostral teeth nearly reaching to tip of rostrum...... ,..., . Palaemonetesvulgaris Carpusof secondleg in adult fernalelonger than palm;cutting edges of movableand fixed fingersof chelalacking smallteeth; tip of rostrumdagger-like without teeth . Palaemonetespugio

47 Carapacewith 8 lateralteeth, posterior-most lateral tooth greatlyenlarged, with sharppoint extending well beyond other anterio-lateralteeth; posterior pair of legswith terminal segmentflattened or paddle-like modified for swim- ming! Fig. 53! . . Portunidae!48 Carapacewith lessthan 6 later' teeth,posterior-most anterio-lateral tooth not greatlyenlarged; posterior pair of legs with terminalsegment not flattenedor paddle-like .49

48 Frontalmargin of carapace between eyes! with 4 teeth . Callinectessapidus Frontal marginof carapacewith 6 teeth. Callinectes similis

49 Carapacewith 2 orless lateral teeth includinganterio-lateral angle! .54 Carapacewith 3 or more lateral teeth .50

50 Frontal margin of carapacedouble, forining a shallowgroove Fig. 58c! carapacewith distinct pubescent,transverse ridgesof raisedgranules; fingers of chelaewhitish!. R hithropanopeus harrisii Frontal margin of carapacesingle, lacking shallow groove ,51

51 Fingersof chelaewhitish, inovable finger with persistentpink or purplecolor confined to uppersurface of proximal half. Eury tium!imosum Fingersof chelaedark except for whitish tips! . 74

52 Movablefinger of majorchela lacking prominent enlarged tooth on lower margin Fig. 58a!; minor chela with spoon- shapedfingers inner face of thirdrnaxilliped with raised, oval red spot in bothsexes!.... Furypan<>pensdepressus Movablefinger of majorchela with prominent large tooth on lower margin Fig, 55a, 56a! 53

53 Innerface of thirdmaxllliped with ova!red spot in maleonly; carapace dorsally flattened, usually brownish with whitish-yellowmarkings . Panopeusherbsrii forma simpsoni Innerface of thirdmaxiliiped with oval red spot in bothsexes Fig. 55c!; carapace dorsally convex, usually unifornt bluish-grayto dark blue . Panopeusherb~rii fornia obesa

54 Eyestalks elongate, over 4 timeslonger than wide, both originating in middle third of frontalregion of carapa-e; maleswith one chela greatly erdarged . .. Uca! 57 Eyestalks only moderately elongate, less than 3 timeslonger than wide; originating in outer third of' frontal region ol carapace;chelae of malenot greatly dissimilar in size .. 55

55 Carapacenearly square, margin bnrnediately behind post-orbital tooth unarmed or with blunt weak tooth or low process;outer face of thirdmaxilliped with oblique ridge of densesetae Figs. 59, 60!...,....., .. Sesarvia!56 Carapacedistinctly narrowing posteriorly, lateral margin immediately behind post-orbital tooth armed with a well- developedsharp tooth Fig.61!: outer face of thirdmaxilliped lacking ridge of densesetae Pa<.hygrupsus rransversus

56 Lateralmargin of carapaceimmediately behind outer-orbital tooth armed with blunt tooth or process;distal segments of firstthree walking legs densely pubescent Fig. 59! . Sesarn

57 Innerface of palmof malelarge chela with oblique ridge of tubercles Fig. 62a-f, k-n!...... , ... 59 Innerface of palmof malelarge chela lacking ridge ot tubercles Fig. 62gP!. 58

58 Cardiacdepression of carapacerust-red; large chela of malewith innerface of carpusbright reddish-orange to purplish-red Fig. 63a! .. . Ucapanacea Cardiacdepression of carapace grayish-brown to diffuse-black; large chela of malewith inner face of carpus having reddishpigment, but not bright reddish-orange or purplish-red Fig. 63b!. .Ucapugilaror

59 Largemale chela with carpus usually having distinct enlarged, spine-like tubercle on inner face Fig 62m!; ridge of tuberclesstrongly elevated forming acute triangular process atjunction with carpal cavity Fig, 62n!, Ucaspinicarpa Largemale chela with carpus not having enlarged spine-like tubercle on inner face; oblique ridge on palm not forming stronglyelevated triangular process. .60 Carapacewith anteriorthird of bothlateral margins straight; male large chela whitish, elongate, delicate; sn

61 Front of carapace!less than one-third of carapacewidth Fig. 62i!; frontal region of carapacewith reddish brown- rnaroonreticle pattern may overlap blue! Figs.62i, 63e!...... ,,,...,, . Ucarupax Frontgreater than one-third of carapacewidth Fig.62j! .62

62 Secondand third walking legs with ventral pubescence; joints of chelaenot red usuallypale orange!; trontal reg

!aws~ B ct 0 lobe ligule! 'o0g 0

~ setae

i palp

oC 0 tomial cirri be ligule!

rapodiurn

Figure64. Polychaetemorphology: A! anteriorend of nereid Figure 65, Polychaete morphology: generalized parapodium of polychaete modfied from Hartman, I951!; B! uncinus modified nereid polychaete. seta!of Hobsonfajforida greatly magnified!. AhlTERIOR

osta!

sp

vari

I 0

'o 0 colutn ter lip

POSTERIOR siphonalcanal Figure 67, Schematicdrawmg of the left sinistral!valve of a bivalve Figure 66, Schematicdrawing of a gastropodmollusk shell, molluskshell, 76

snlrnnui nn'I

nrIIanna rcI anrsnnsl cndopod rsupnd

Figure68. Schematicdrawing of a mysid family Mysidae! showing lateral and doral views from Stuck, perry and Heard, l978a!.

ftAF ON P6

elson

Uropods

Peroeopods

Figure69, Externalmythology of a gammarideanarnphipod from Bousfield,1973!.

pahe ~Ie a I aI h rostrum

Figure 70. Schematic drawing of shrimp in lateral view; ai,, appendix interne; a.s,, antennal spine; a. sc., anten- nal scale;b., basis;b.s., branchiostegal spine; cp., carpus; anlenna ex., coxa; d., dactyl; end., endopod; ep., epipod; ex,, exopod; h.s,, hepatic spine; i., ischium; m., merus; Ihrrdmaa Ilrped p., propodus; p,g,, postorbital groove; p.s., pterygos- ~ubc hale tornian spine; s.s., supraorbital spine; st., stylocerite from WilRuns, l 965!, chela. Wd SabdlvrdedcdPus d h ~ op~/I, d L au an 77

onlonn~ ln Onlnnnd onrorolotnralbordnr ~ ro ortniol

pro'lo. nopoIIC F"f.,

Co

ponlnrololorolborder'

Figure71. Schematicdrawing of brachyurancrab in dorsalview; Figure72. Schematic drawing of brachyurancrab in ventralview; areasof carapaceindicated; legs of right sideonly shown;bbasis; areasof carapaceindicated; legs of left sideonly shown; b., basis; cp.,carpus; d., dactyl;i., ischium;m., merus; p., propodus from cp.carpus; cx., coxa; d., dactyl; end., endognath; ex., exognath; WiUiams, 1965!. i,, ischium;m., merus; p., propodus from Williams, 1965!.

dolaai

pie

onipectinate

0 G I n~l propodua

chetate

i pactmate H

proximalarticle oniramna b iramna

~ dntal article mandable

Figure73, Somemorphological features referred to in thisguide. 78

GLOSSARY

adductor muscle: a muscle that holds the valves of a bivalve chela pl. chelae,adj. clrelate!: claw; pincer-likeor scissor- mollusk together. like distal part of crustacean appendagein which a distal adductor muscle scar: scar or feature on inner surface of prolongation of the propodus fixed finger! opposes the bivalve shell that indicatesthe placeof attachmentof an dactyl movable finger! Fig. 73!. adductor muscle Fig. 66!. chelicerae; claw-like mouth parts of horseshoe crabs and anterior: in bivalve inollusks, forward end of a bivalve arachnids. shell Fig. 67!; in polychaetesand crustaceans,toward chondrophore: a pit, or spoon-likeshell', in the hingeof a the head or front end. bivalve, such as Bangia, into which fits a chitinous aperture: an opening; the cavity or opening of a gastropod cushion, or resiliurn Fig. 67!. shell Fig. 66!. cirrus pl. cirri!: in polychaetes,refers to a sensoryprojec- axial: in the same direction as the axis; from apex to the tion, usually slender and cylindrical, from the upper part baseof a gastropodshell; axial rib seeFig. 66!. of the notopodium dorsalcirrus! or from the under part beak: the earliest formed part of a bivalve shell; the tip of the neuropodium ventral cirrus!. Tentacle-like nearthe hinge;the umbo Fig, 67!. appendages of anterior segments near head peristomial biconate: biconic; similar in form to a double cone; the cirri! see Figs. 64, 65!. spire about the same shape and size as the body whorl, cypris stager larval settling stage of a barnacle. bidentate: with two teeth, dactyl; last or distal segmentof a crustaceanleg Fig. 70!. biramus: with two branches or rami Fig, 73!, denticles: small projections, rcsernbhngteeth, around the bipectinate: in reference to gastropod gill, having both inarginof the gastropodaperture or the pelecypodvalve. margins of gill with a series of comb-like projections or detriti vore: an aniinal that eats detritus lamellae Fig. 73!. detritus: particulate organic and inorganic matter. body whorl: the last and usually the largest turn in a diatom: microscopicplant; a kind of unicellular or single- snail's shell Fig. 66!. celled alga. brackish: referring to sea water that has been diluted with diecious; individuals of a species having distinct sexes fresh water. Most estuaries are brackish due to mixing either male or fernale!. of river water with sea water. distal: away from the body; toward the extremity of an branchia pl. branchiae!: a gill; a specialized process, appendage,ramus, or article Fig. 73!; opposite of lamella, or appendage through which respiratory gases proximal. oxygen, carbon dioxide! are exchanged. dorsal; back for dorsal orientation in bivalve mollusks, brood plates: oostegites; plate-like processes originating see Fig, 67!, from the bases of some legs of peracaridan crustaceans. ecdysis: molting or sheddingof "old shell" exoskeleton! Collectively the brood plates form a rnarsupiurn in crustaceansas part of growth phasein which the new Fig. 68! or brood chamber for incubating the young of soft shellexpands in sizebefore hardening takes place. peracaridans. ecosystem: taken as a whole, all the organisms in a com- byssal threads: a series or clump of thread-like fibers that munity plus all the associatedchemical and physical environmental factors, serve to anchor certain bivalves, such as mussels,to some ectoparasite: a parasiticanimal which infestsor infects the support Fig. 22!, external surface of its host. calcareous: of hard calcium carbonate. endopodite: inner ramus or limb of crustacean biramus capillary seta: in polychaetes, a long, slender, simple, appendage Fig, 73!. taperingsetae Fig. 3d!. epifaunal: living exposed, above or on the substratum sur- carapace: hard outer protective covering of some animals. face; inay be with or without attachment. In crustaceans,it covers the head and gill region. epitoke: modified polychaete reproductive stage, often cardinal teeth: the main and usually largest teeth in a swarming. bivalve hinge located just below the beaksor umbones estuary adj. estuarine!: the brackishwater regionsof and Fig. 67!. near river mouths influenced by tides. carina: keel or ridge. euryhaline: having or living in a wide spectrum of salinities carnivore: an animal that eats other animals; meat eater. ranging from nearly fresh water to full strength seawater. exopodite: outer ramus or limb of crustacean biramus carpus: third segment or article from the distal end of a appendage Fig. 73!. crustacean leg. exoskeleton: the external chitinous "shell" covering cephalon: head. crustaceansand many other arthropods. cephalothoraxr body division in many higher crustaceans falciger: a distally blunt and curvedseta Fig. 2c! found in representing the fusion of the head and one or more many polychaetes. thoracic segments.In crabs,the fusion of the head and gnathopod sjr terin applied to the first two pairs of legs all thoracic segmentsis complete. usually specializedfor grasping!of amphipods Fig. 69!. 79

hermaphroditic;having male and femalesex organs in the palp. in polychates,fleshy projectionfrom prostomium saine individual. Fig, 64!; inandibularpalp of crustaceans,distal articu- heterogomph: referring to a conipoundpolychaete seta in latedpart of mandiblethat functionsas an aid in feeding which the articulation is clearly oblique to the long axis or cleaning Fig. 73!. of the shal't Fig. 2c, d, f!. papillae: sinall, ripple-likeprojections, hoodedhook seta; a relativelyshort, blunt, often distally paragnalh s!:chitinous denticle in the pharyngealcavity curved and dentate seta which is distally covered by a of nereid polychaetes everted pharynx forms the delicatechitinous envelop or guard Fig. 3e!. "proboscis"! Figs. 2j, 64!, host: an organisinto whicha parasiteor othersyinbiont is parapodium pl. parapodia!:in polychaetes,the segment- attached or otherwise associated. ally arrangedlateral projections carrying setae; "foot." indicator organism: an organismtypical or representative partsper thousand ppr, o/oo!: usedin describingthe con- of a certain habitat or certain environmental conditions. centration of salt in brackishand inarine waters;refers infaunalanimal: spendingall or partof its life buriedwithin to the nuinberof grainsof salt per thousandgrams of the substratuni. water. Full strengthsea water has approximately36 intertidal: occurringbetween the high and low tide zones. gramsof saltper thousand grams of water. keel: a longitudinalridge, carina, or prominentspiral ridge peduncle: the basalsegment or segmentsof biramusor uni- usuallymarking a changeof slopein the outline of a mousappendanges antennae,pleopods, uropods! Fig,73!. shell or exoskeleton. pelagic; pertainingto or inhabitingthe opensea far from lamellae: tliin plates or ridges. land, larva: a youngstage of an animalthat differsrnorphologi- pellialline: a grooveor channelnear the inner margin of a cally from the adult stage. bivalve shell, where the mantle is madefast to the lower krteral: to the side of midline of the body. part of the shell.When this line is continuousand not ligule: parapodiallobe; finger-shapedmajor processon a markedwith a pellialsinus it issaid to besimple Fig.67!. polychaeteparapodiuin Fig. 65!. pellial sinus: a U-shapedindentation in the pellial line marsupium; seebrood plates. producedby the siphon Fig. 67!. rnaxilliped s!:mouth parts originally derivedfrom the periostracum:outer layer of a shell,composed of a form modification of the first 1 3 pairs of thoracic appen- of sclerotizedprotein, or conchiolin. dages;originating directly posterior to the maxillae see phytoplankton: plant plankton. I igs. 70, 72!, plankton adj. planktonic'!: floating and drifting aquatic meiofauna:small infaunal or surface-dwellinganimals organismswhose primary movements result from water e.g., harpacticoidcopepods, nematodes, invertebrate movement rather than their swimming efforts. larvae!that will passthrough a 0.5 mm sieve,and are pleon: abdoininalsegments having pleopods Fig, 69!. retained by a 0.1 mm sieve. pleopod s!; swimmeret;ventral appendages excluding mesohaline: brackish water with intermediate salinities uropods!in amphipodsof anyof the first five abdominal greaterthan 2 pptand less than 36 ppt! rangingbetween segmentsin peracaridanand decapodcrustaceans Figs. oligohalineand full strengthsea water. 68, 69, 70!. mucronation: acuteprocess or tooth. pleotelson:posterior body part of isopodsand soine other multiarticulate: having two or inore seginentsor articles crustaceansresulting from the fusion of the telsonwith Fig. 73!. one or more pleonal segments. notopodium: dorsal branch of a polychaete parapodium posterior: situatedaway from the anteriorpart of a shell Fig. 65!. or body; toward the "tail." oligohaline:low salinity conditions more than 0.5 ppt proboscis: a long, flexible snout; when everted, the andless than 2 ppt!between fresh water and mesohaline pharynx of polychaetesis often calleda proboscis. conditions. propodus: secondsegment or article from the distal end omrrivore: an animal that eats a variety of animal and of a crustaceanleg Figs. 70 73!. plant substances;lacks specialized diet. prostomium pl. prostomia!: in polychaetes,the anterior oostegitesr seebrood plates, pre-segmentalpart of the body anterior to the mouth, operculum: a coveror lid; in gastropodmollusks, a sheH- enclosingat leastthe anteriorpart of the brain, often like or hornyplate attached to the foot andused to close with antennae and eyes; part of polychaete "head" the apertureof theshell; in polychaetes,a "stopper" for Fig. 64!, the tubes of some tubicolous worms when the occupant protogynic n. protogyny!: type of herniaphroditicdevel. is retracted Fig. 4!. opmentin which the femalereproductive system becomes oral: referring to the mouth, functional beforethe malereproductive system. Opposite ovoviviparous; retention of developingeggs within the ovi- of protandrous. duct of fema]euntil young are fully formed beforebeing proximal: toward body; closestto body Fig. 73!; opposite released. of distal. 80

pubescent: coveredwith densemat of fine hair-like setae. end, of an appendageor segment, radula: in gastropod mollusks, .a rasp-like organ, subtidal: below low-tide zone. or lingual ribbon arined with tooth-like processors;used smimmeret: see pleopod s!. in feeding. synonym: two or more scientific namesreferring to the ramus pl. rami!: branchof an appendage. same speciesor taxonomic category, reniform: kidney-shaped. telson: terminal segmentfollowing the sixth abdominal resilium: a triangularligament sturcture; a toughchitinous segmentof higher crustaceans;absent in some groups pad, residing in a chondrophoreor pit, along the inner Figs. 68, 70!. hinge marginof a bivalvewhich causesthe shell to spring tentacular: tentacle-like. open when the musclesrelax. thorax adj. thoracic!; in crustaceans,the central part rostrum: a medial anterior extension of the cephalon or of the body between the head and abdomen; com- carapacebetween the eyes;canbe longand well developed, pletely covereddorsally in decapodcrustaceans. Chela reduced, or absent Fig. 70!. and legsare thoracic appendages. serrate: a formation resemblingthe toothed edgeof a saw. trochophore: ciliated larval stageof polychaetesand some sessile: attached to substratum. mollusks. seta pk setae,adj. setose!: a needleor hair-like extension ambo pl. umbones!: seebeak. of integument,cuticle, or exoskeleton. uniarticulate: havingone segmentor article Fig. 73!. setiger: in polychaetes,a segmenthaving setae Fig. 64!. unipectinate; in referenceto gastropodgill, havinga single siphonal canal: a posterior prolongation of a gastropod row of coinb-like processesor lamellae l'ig. 73!. shell forming a narrow grooveor canalto accommodate uniramus; with one branchor ramus Fig. 73!. the siphon; this structure is characteristicof hteogastro- uropod: appendagesarising from the sixth abdominalseg- poda Fig. 66!; siphonal notch formed by the sinusat ment of many higher crustaceans;in amphipods,the the distal tip of siphonalcanal. 4 5 abdominal segmentsalso have uropods; in adult somi te: body segment. brachyurancrabs, uropods are absent Figs. 68 70!. spiniger: in polychaetes,a setathat tapersto a fine point urosome: abdominalsegment or segmentshaving uropods Fig. 2d!. Fig, 69!. spire: upper whorls, from the apexto the body whorl, but varix pl, varices!: prominent, raisedrib on the surfaceof not including the body whorl Fig, 66!. a snail shell, causedby a periodic thickening of the lip statocyst: balancing organ in many crustaceansused in during rest periodsin the sheH'sgrowth Fig. 66!. body orientation. veliger: a larval stage of mollusks, which has a ciliated stolon: stem-like attachment structure of hydroids. band or bands and often an embryonic shell. suberlual: nearly equal. ventral: the lower side,opposite the dorsalarea Figs.67,73!. suboval: irregularly oval. verge: penis,male copulatory organ of a gastropodmollusk. subterminal: occurring very near the end, but not at the whorl: a completeturn, or volution, of a snailshell Fig.66!. 81

INDEX

Melampuscoffeus 20 frg 15 25 frg 28 Melarnpusfloridana, 20 Almyracuma proximoculi, 31 Gammarussp., 40, frg. 41 Melrta elongata,37 Almyracuma sp31, fig. 33 Gammarusmucronatus, 37, fig, 41 hfelita intermedia, 37 Amphicteisfloridus, 8 Gammarustrgrinus, 37, fig. 41 Melita longisetosa,37 Amphieteisgunneri J70ridus, 8 Geukensiademissa, 22, fig. 20; 25, fig. 28 Metiia nitida, 37, frg, 42 Arnygdalumpapyrium, 23, tig. 23 Geukensiad, granosissima,22 hielita spp., 37 fig. 42 Metongenacorona, 18, lig. 13 Apseudes sp., 30 Grandidierella bonnieroides, 38, fig. 43 hfembranopora, 10 Arcatia tonsa, 35 hfercierellopsisprietoi, 9 Arcuatuia demissa, 22 Modiolusdemissus, 22 Asellus obtusus, 34, fig. 39 hfunnareynoldsi, 34, fig. 37 Assimineasuccinea, 15; 16, fig. 9; 25, fig. 28 fialmyrapseudesbahamensis, 30 Haploscoioplosfragr'lis, 6 Mysidopsisalnryra, 28; 29, fig. 30 Hargeriarapax, 29, fig. 31 Mysidopsr'sbahia 28; 29 fig, 30 Myrttopsis =Congeria! Ieucophaeta, 22, Heleobopsdoctma, 13 Heleobopsspp., 12, fig. 7; 13;14, frg. 8 fig. 21 Balanusspp10 Hereromasrusjiiiformis, 7, fig. 3; 8; 9, fig.5 hfyzobdellalugubris 4 Balanus eburneus,26 Hobsoniaflorida, 3; 7, fig. 3; 8; 29 Balanussubalbidus, 26 Bowmaniellaspp., 28, fig. 30 Hyalellaazteca, 40, fig. 45 Hydrobiaboonae 15 Bowmuniella brasiliensis, 28 htamutycastisabiuma, 5, fig. 2; 6; 9, fig.5 Hydrobraiacksonr, 13 Bowmaniellu floridana, 28 Veanthessuccinea, 4; 5, fig. 2; 9, fig. 5 Hypaniolaflorida, 3; 8; 9, fig.5 Branchiodontesrecurrus, 24 Ittemarostetiacf. vectensis,3, fig. 1 Hypaniola grayi S Aematosretlapellucida, 3 C /Vereissuccinea, 4 Weritinarecli vata, 10; 11, fig.6 Callianassajamaicense, 47 Ischadiumrecurvunr, 23, fig. 22 %eritinausnea, 10; 11, fig. 6; 25,frg. 28 Callianassatrilobata, 47 Ãoromastus sp., S Caliinectessapidus, 48; 49, figs.53, 54 Callrnectessirniiis, 50 0 Capitellucapitata, 7,fig. 3; 8; 9, fig. 5 Laeonereisculveri, 5, fig. 2; 6; 9, fig, 5 Curneophallusturgidus, 46 Leptocheliadubiu, 29 Ocypode quadrata, 56 Cassidinideaiunifrons, 32 Odostornrahvrda 19 Cassidinideaovalis, 32, fig. 35 Leprocheliasp., 29 Leptocheharapax, 29 Odostomiaproducta, 19 Cerithideaculifornica, 16 Onobopsspp., 13 Cerithideacosrata, 16, fig. 10;17; 25, fig. 28 Limuluspolyphemus, 26 Onobopscf.jacksoni, 12, fig. 7; 13; 14, fig. 8 Cerithideaplicu lose, 16, fig. 10; 17; 25, fig. 28 Iirceus sp,, 34; 35, fig. 39 Littorinairrorata,17, fig. 11;18, fig. 12; 25, Onobopscrassa, 13 Cerithideascaluriformis, 16, fig. 10; 17; Orchestiaagilis 44 fig. 28; 50 25, fig. 28 Orchestiacostaricana, 42; 43, fig.48 Cerirhidea spp., 16, fig. 10 Lirtorina angulifera, 17 Littoridina monroensis,13 Orchestiagrillus, 41, fig, 46; 42 Chthamalus fragilis, 26, fig. 29 Orchestiapalustris, 41 Clibanarius vi rratus, 48, fig. 52 Littorrdina Texadinaj sphincrostoma, 12, fig. 7; 13; 14, fig. 8; 15 Orchestiaplatensis, 42; 43, fig, 49 Corophiumlacusrre, 40, I'ig.44 Orchestrasp., 42; 43, frg. 48 Corophiumiouisianum, 29; 39, fig. 44; 40 Littoridinopsmonroensis, 11; 13; 14,fig, 8 I.ittoridinopspalustris, ll; 12,fig. 7; 14, Orchestiauhleri, 42, fig. 47 Corophiumspp39, fig. 44 Oxyurostyh'ssmithi, 31 Congeria,22 fig. 8; 15 Crussostreavirgr'nica, 18; 24, fig. 26 Littoridinops sp., 13 Cyuthurapolrta, 32, fig. 34 Li ttoridinopstenuipes, 11; 13; 14, fig. 8 Cyrenoidafloridana, 23, tig. 24;25, fig. 28 Loandaliaamericana, 6 Lolliguncula brevis, 10 Pachygrapsusgracilis, 55 Lycastopsishummelincki, 6 Pachygrapsus transversus, 55 Lycastoidespontica, 6 Palaemonereskadiakensis, 46; 47, fig. 51 Lycustopsistecoiutlensis, 6 Palaemonerespaludosus, 36; 46; 47, fig.51 Detracia flondana, 20, fig. 16; 25, fig. 28 Palaemonetespugio, 35; 45. fig. 50; 46; 47, Doilfusenrischandleri, 39 fig. 51 Palaernonetesvuigaris, 46; 47, fig. 51 Macrobrachium arnericanum, 10 Panopeusherbstii, 50; 51, figs.5.5, 56 Panopeusherbstii forma obessa,50; 51, Fdoteu cf. montosu, 32 Macrobrachium obione, 36; 46; 47, fig. 51 hfanayunkiaaesruarius 9 fig. 55 Furypanopeus depressus,50 Panopeusherbstii forma simpsoni, 51, fig.56 Furyrium limosum, 50; 52, fig. 57 hfanayunkiaspp. 9 fig,5 Manayunkiaspeciosa, 7, fig. 3; 9 Parandalia americanu, 6; 7, fig. 3; 9, fig. 5 Mediomastuscali forniensis, 8 Parhyalehawaiensrs, 36 hfelumpusbidentatus, 19; 20, fig. 15; 25, Penaeusaztecus, 44; 45, fig, 50 Ficopomatus miumiensis, 9, figs. 4, 5; 11 fig. 28 Penaeusfluviatilis, 46 82

Texadina barret ti, 15 Penaeusseti ferus, 45, fig. 50; 46 Texadinasphinctostoma, 12, fig. 7, l 3;14, Polymesodacaroliniana, 2I, fig. 17;22; 23; fig. 8; 15 25, fig. 28 Sayellaspp., 18; 19, fig. 14;25, fig, 28 Polymesodamaritima, 21, t'ig. 19; 22; 25, Scoloplosfragilis, 6; 7, fig. 3; 9, tig. 5 Sesarmacinereum, 54, fig. 60; 58 fig, 28 Pontodrilus bermudensis, 3 Sesarrnareticulatum, 50; 53, ftg. 59; 54 Sphaeromadestructor, 33, fig. 36 Ucaspp., 50; 57, fig. 62; 59, fig. 63 Probopyrus bithynis, 36 Ucalongisignali s, 50; 56; 57, fig.62; 59, Prohopyrus floridensi s, 36 Sphaeromaquadridentatum, 34 fig, 63; 60 Probopyruspandalicola, 35, fig. 40; 46 Sphaeromaterebrans, 33, 1'ig.36 Sphaeropomatusmiamiensis, 9 Ucaminax, 38; 5 7,fig. 62; 59, fig, 63; 6 l Probythinella = Vioscalbajlouisianae, 15 Ucapanacea, 56; 57, t'ig.62; 59, lig. 63; Pseudocyrenafloridana, 22 Stenontnereis martini, 5, fig, 2; 6; 9, t'ig. 5 Srreblospiohenedicti, 7, fig. 3; 9, fig. 5 Ucapugilator, 56; 59, tig. 63 Pseudocyrenamaritima, 22 Ucapugnax, 59, tig. 63; 60 Pyrgophorus cornatus, 15 Syncera succinea, 15 Uca pugnax virens, 60 Pyrgophorus parvulus, 15 Ucarapax, 57, tig. 62; 59, tig. 63; 60 Pyrgophorusplatyrachis, 15 Uca rapax Iongtsig>talis,60 Pyrgophorvssp., 12, t3g,7; 14, t'ig.8; 15 Ucaspeciosa, 58; 57, fig. 62; 59, t'i . 63 Ucaspeciosa spinicarpa, 57, tig. 62; 58;59, R Tagclusgi bbus, 24 Tagclusplebius, 24, fig, 25 fig. 63 Ucaspinicarpa, 57, fig. 62; 58; 59, lig. 6.3 Rangiacuneate, 15; 21, fig, 18: 25, fig..28 Talitroides topotvm, 41 Rangia =Rangianella!flexuosa, 22 Taphromysis bowmani, 27; 29, fig. 30 Uca virens, 56, 60 Rhithropanopeusharrisii, 52; 53, fig. 58 Taphromysis louisianae, 27; 28; 29, iig. 30 Upogebiaaffinis, 47