Grandidierella Japonica Subphylum: Malacostraca Order: Amphipoda, Gammaridea a Brackish Water Amphipod Family: Aoridae

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Phylum: Arthropoda, Crustacea Grandidierella japonica Subphylum: Malacostraca Order: Amphipoda, Gammaridea A brackish water amphipod Family: Aoridae

Description Size: Males up to 22 mm in length, females flagellum is equal to peduncle and consists of 13 mm long (San Francisco Bay, Chapman 18 articles (Stephensen 1938). Male antenna and Dorman 1975; Myers 1981). The one longer than its antenna two (Barnard illustrated specimen (a male, from Coos Bay) 1973), however female antennae are of equal is 10 mm in length (Fig. 1). size (Stephensen 1938) (female not figured). Color: Black head, mottled grey to grey Antenna 2: Length from ¾ of to brown body (Chapman and Dorman 1975) longer than antenna one (Chapman and with distal parts of limbs white (Stephensen Dorman 1975) (see antenna 1). Spines 1938; Chapman 2007). This specimen white present on peduncle articles 3–5. Male (preserved in ETOH). second antenna stout and flagellum with General Morphology: The body of seven articles (Stephensen 1938). Female amphipod crustaceans can be divided into second antenna length in equal to antenna three major regions. The cephalon (head) or one and fifth article of peduncle with four cephalothorax includes antennules, antennae, strong spines. Female flagellum with six mandibles, maxillae and maxillipeds articles (not figured). (collectively the mouthparts). Posterior to Mouthparts: Mandible with large the cephalon is the pereon (thorax) with molar, toothed lacinia mobilis, incisors and seven pairs of pereopods attached to long 2-articled mandibular palp with third pereonites followed by the pleon (abdomen) article setose. Maxilliped with 4-articled palp, with six pairs of pleopods. The first three sets article four claw-like and article two twice the of pleopods are generally used for swimming, length of one and two (Chapman and Dorman while the last three are simpler and surround 1975). Outer maxilliped plates twice the the telson at the animal posterior. The length of inner plates. gammarid family Aoridae is characterized by separate urosome articles and a biramous Pereon: third uropod. They also have a short Coxae: Reduced (Chapman and (sometimes absent) rostrum, a long first Dorman 1975), serially arranged and barely antenna and a fleshy telson. Grandidierella contiguous (Barnard 1973) (Fig. 1). Coxal japonica (see plate 262A, Chapman 2007), plate one with a medial-ventral tooth however, resembles the family Corophiidae (Chapman and Dorman 1975) (just slightly more closely due to the uniramus uropod produced in illustrated specimen). three (Chapman 2007). Gnathopod 1: Male gnathopod one is Cephalon: greatly enlarged, “carpochelate” (i.e. not Rostrum: filtering type) (Grandidierella, Barnard 1973; Eyes: A single, oval-shaped, lateral Chapman 2007). Articles two and five greatly eye (Kozloff 1974) that are black and medium enlarged and subequal (Chapman and in size (Stephensen 1938) (Fig. 1). Dorman 1975). Article two oval, article three Antenna 1: The first antenna in small, article four small and elongate. Article males is more than ½ body length (Chapman five with sides parallel and with one enlarged and Dorman 1975) and is much shorter in tooth forming thumb and two smaller teeth females. The peduncle is with short (Grandidierella, Barnard 1975). Anterior edge accessory flagellum in both sexes (Fig. 1b). of article five with 18–20 transverse fine The male flagellum has 20 articles and is a ridges ("stridulating organs’’, Stephensen little longer than peduncle. The female 1938) and four spines (Figs. 1, 1a). Female

A publication of the University of Oregon Libraries and the Oregon Institute of Marine Biology Individual species: http://hdl.handle.net/1794/12709 and full 3rd edition: http://hdl.handle.net/1794/18839 Email corrections to: [email protected] gnathopod one is small, but larger than rostrum, long first antenna, gnathopod one gnathopod two. Article two is setose and larger than two (in males), a fleshy telson, a narrow (Stephensen 1938) (Fig. 5). long seventh pereopod (longer than the sixth), Gnathopod 2: Male gnathopod two is distinctly separate urosome articles and a simple and much smaller than gnathopod biramous uropod three. There are four aorid one. Article two is twice the length of article amphipod species that are not native to the five. Article three is short and dactyl is not northeastern Pacific coast (e.g. Aoroides chelate (Fig. 1). Female gnathopod two is secundus, Microdeutopus gryllotapla), one of setose, is smaller than gnathopod one and which is G. japonica. At least two aorid with article two about 2/3 length of male genera that are quite similar to Grandidierella: article two (Barnard 1973). Paraoroides, and Aoroides (family Aoridae). Pereopods 3 through 7: Simple, not Paraoroides species have a uniramous third prehensile (Barnard 1973) and increasing in uropod (as in G. Japonica), but this ramus is length. A character of the Aoridae is a only as long as the peduncle, not twice or seventh pereopod that is longer than the sixth three times as long (Barnard 1973). In (see plate 269C, Chapman 2007) and the Paraoroides, the first gnathopod is not seventh pereopod in G. japonica is very long carpochelate, but only slightly enlarged, the (Fig. 1). Female pereopods are with narrow gnathopods are equal in size. The third second articles (Stephensen 1938). article of the first antenna is not elongate, as it Pleon: is in G. japonica. Aoroides species (six local) Pleonites: Third pleonite is without have an immensely merochelate male first dorsal tooth (Barnard 1975) gnathopod (Barnard 1975), quite different Urosomites: All three urosomites from that of G. japonica. Article four is short (Fig. 1). The first uropod is biramous elongate, article five is oval, but lacks teeth. and longer than the second or third. The The gnathopod is the filtering type, with long peduncle is with peduncular process and two setae. The third uropods in this genus are anterolateral spines on urosomite (Barnard biramous, not uniramous as in Grandidierella. 1969) (Fig. 3). Second uropod is also Aoroides columbiae is a Pacific coast species. biramous (Grandidierella, Barnard 1975) and Other species of Grandidierella have not been with thin peduncle and long rami (Barnard recorded from our area, include a tropical 1975) (Fig. 4). The third uropod is uniramous, species, G. nottoni, and four freshwater without hooked apical spine or long setae species. Grandidierella japonica closely (Barnard 1975) (a defining character of G. resembles amphipods in the gamily japonica). It is not fleshy, blunt or elongate Corophiidae (Chapman 2007) and the ramus is three times as long as the The gammarid family Corophiidae is peduncle (Barnard 1973) (Fig. 6). characterized by individuals that build U- Epimera: shaped tubes in both soft sediments and on Telson: Telson uncleft and somewhat hard surfaces, sometimes forming dense swollen (Kozloff 1974), with button-like aggregations. Species can be dramatically morphology and medial groove (Chapman sexually dimorphic and, while males may be and Dorman 1975) (Figs. 1, 2). easier to identify with taxonomically relevant Sexual Dimorphism: Male first gnathopod characters including the rostrum and article two is expanded and article five is peduncle of second antennae, most females large, with parallel sides, teeth and can be reliably identified to species as well stridulating organ. All features are lacking in (Chapman 2007). Five corophiid genera females. Male antenna one is also longer occur locally, Americorophium, Corophium, than two and female antennae are equal. Crassicorophium, Laticorophium and Monocorophium. The three common Possible Misidentifications estuarine species in this guide (A. brevis, A. The Aoridae are a family of gammarid salmonis, A. spinicorne) were previously amphipods that are tube-building suspension members of the genus Corophium (see feeders found in marine and estuarine Shoemaker 1949), but were transferred to the habitats. They are characterized by a short

Hiebert, T.C. 2015. Grandidierella japonica. In: Oregon Estuarine Invertebrates: Rudys' Illustrated Guide to Common Species, 3rd ed. T.C. Hiebert, B.A. Butler and A.L. Shanks (eds.). University of Oregon Libraries and Oregon Institute of Marine Biology, Charleston, OR. genus Americorophium in 1997 (Bousfield japonica). Photis species have elongate and Hoover 1997). coxae and a normal first gnathopod, but an Other common gammarid families enlarged second gnathopod that is often include the Ampithoidae, Cheluridae, highly sculptured. The third uropod has an Ischyroceridae, Podoceridae, and lsaeidae elongate peduncle. (for key see Chapman 2007). The Ampithoidae have a poorly recessed head Ecological Information (Barnard 1973) and a short third article on the Range: Grandidierella japonica is native to peduncle of antenna one. At least one ramus Abasiri River, Hokkaido, Japan, from which it of the third uropod in this family is very setose was introduced to U.S. Pacific harbors with terminally and the third uropod also has Crassostrea (commercial oyster), Tomales, curved hooks on the end of its stout ramus Bolinas, and San Francisco, California, (Barnard 1975). The Ampithoidae have a possibly as early as 1928 (Chapman and thick, uncleft telson. In our area there are Dorman 1975). Current distribution includes several species of Ampithoe including A. the Fraser River, Canada, Bahia San Quintin, lacertosa and A. valida. The Cheluridae are a Hawaii, England and Australia in addition to wood-boring group that utilize the holes in the northeast Pacific (Chapman 2007). For wood left by boring isopods family with a huge west coast invasion history, see Fig. 1, Pilgrim dorsal tooth on the third pleonite. The et al. 2013. Genetic barcoding data suggests urosomites form a box-like structure, and the two cryptic G. japonica species – both present second uropods are “flabellate” (i.e. paddle- in San Francisco Bay with one expanding like). Chelura terebrans is an introduced northward and the other southward (Pilgrim et species found on the Pacific coast and is the al. 2013). only cheluird species found in this region Local Distribution: Coos Bay sites include (Chapman 2007). The Ischyroceridae is the South Slough and North Bend Airport another closely related family. Members have (Gonor 1979). an unusual thorn-like rostrum and a rather Habitat: Burrows in mud bottoms of bays cylindrical body. The telson is broad and and estuaries where individuals build U- short, and it is the second male gnathopod, shaped tubes, in which pairs can often be not the first, in this family which is found (Chapman and Dorman 1975). Males carpochelate. Ischyroceridae have hooks on also found out of tubes and in tide pools at the outer ramus of the third uropod (like low tide. Grandidierella japonica is sensitive Ampithoidae), but this ramus is short and to a variety of pollutants and is a common slender, not stout. The inner ramus is also subject of toxicity tests (e.g. Nipper et al. slender and void of setae. Local genera 1989). include Cerapus, Ericthonius, Jassa, Salinity: Brackish water in Japan and lschyrocerus, Microjassa and Ruffojassa. introduced into Oregon and California Ericthonius species have a body much like G. estuaries (Chapman and Dorman 1975). japonica, but the first male gnathopod is Unique osmoregulatory tissue of the coxal normal, and the second is carpochelate (the gills allow G. japonica to exist in a wide opposite is true for Grandidierella). At least variety of salinities (Kikuchi and Matsumasa two species occur in our area, E. rubicornis 1993). (=E. hunteri) and E. brasiliensis. In Temperature: Podoceridae both gnathopods (especially the Tidal Level: Intertidal to 10 meters second) are large and subchelate. The first (Chapman 2007). Collected at +1.5 meters urosomite is very long, more than twice the MLLW in South Slough. length of the second. The genera Podocerus, Associates: Introduced with Crassostrea. In Dulichia, and Dyopedos occur in our area. South Slough, associates include the algae, The lsaeidae are marine, tube building Enteromorpha sp., the amphipod, Ampithoe suspension feeders and include the common valida, and sacoglossan, Aplysiopsis smithi. genus Photis. Characteristics of this group California associates include polychaetes, include a recessed head, and an elongate Harmothoe sp., Heteromastus sp., Capitella third article on the first antenna (like G. sp., Neanthes sp., Streblospio sp., molluscs,

A publication of the University of Oregon Libraries and the Oregon Institute of Marine Biology Individual species: http://hdl.handle.net/1794/12709 and full 3rd edition: http://hdl.handle.net/1794/18839 Email corrections to: [email protected] Mya sp., Cryptomya sp., Macoma sp., Bibliography barnacles, B. improvisus, isopods, Gnorimosphaeroma lutea, amphipods, Photis 1. BARNARD, J. L. 1969. Gammaridean sp., Corophium sp., Allorchestes sp., amphipoda of the rocky intertidal of Ampithoe sp., Anisogammarus sp. and the California: Monterey Bay to La Jolla. anemone Haliplanella sp. (Chapman and Smithsonian Institution Press, Dorman 1975). Washington. Abundance: Can be present in great 2. —. 1973. Revision of Corophiidae and numbers seasonally. Third most common related families (Amphipoda). amphipod at North Bend Airport site (Gonor Smithsonian Institution Press, 1979). South Slough, abundances of 27 Washington, D.C. individuals per m2 reported (Posey 1985). 3. —. 1975. Phylum Anthropoda: Crustacea, Amphipoda: Gammaridea, Life-History Information p. 313-366. In: Light's manual: Reproduction: Most amphipods have intertidal invertebrates of the central separate sexes with some sex determination California coast. S. F. Light, R. I. correlated with environmental conditions Smith, and J. T. Carlton (eds.). (Straude 1987). Females brood embryos in University of California Press, an external thoracic brood chamber and Berkeley. irrigate embryos with water produced by 4. BOUSFIELD, E. L., and P. M. pleopod movement. Development within this HOOVER. 1997. The amphipod brood chamber is direct and individuals hatch superfamily Corophioidea on the as juveniles that resemble small adults, with Pacific coast of North America. Part 5. no larval stage. Little is known about the Family Corophiidae: Corophiinae, new reproduction and development in G. japonica subfamily. Systematics and (but see Wang et al. 2009, in Chinese). distributional ecology. Amphipacifica. Larva: Since most amphipods are direct 2:67-139. developing, they lack a definite larval stage. 5. CHAPMAN, J. W., E. L. BOUSFIELD, Instead this young developmental stage and D. E. BOWERS. 2007. resembles small adults (e.g. Fig. 39.1, Wolff Amphipoda: Gammaridea, p. 545-618. 2014). In: The Light and Smith manual: Juvenile: intertidal invertebrates from central Longevity: California to Oregon. J. T. Carlton Growth Rate: Amphipod growth occurs in (ed.). University of California Press, conjunction with molting where the Berkeley, CA. exoskeleton is shed and replaced. Post-molt 6. CHAPMAN, J. W., and J. A. individuals will have soft shells as the cuticle DORMAN. 1975. Diagnosis gradually hardens. During a molt, arthropods systematics and notes on have the ability to regenerate limbs that were Grandidierells japonica new-record previously autotomized (Kuris et al. 2007). Amphipoda: Gammaridea and its Food: Detritivore that feeds on epiphytes and introduction to the Pacific coast of the suspended particles. Also known to be a USA. Bulletin Southern California predator of amphipods and can be Academy of Sciences. 74:104-108. cannabalistic (Chapman 2007). 7. GONOR, J. J., D. R. STREHLOW, and Predators: The benthic carnivorous fish G. E. JOHNSON. 1979. Ecological Clevelandia ios, Hypsopsetta guttulata, assessments at the North Bend airport Gillichthys mirabilis, Fundulus parvipinnis extension site. School of (Tijuana estuary, West et al. 2003). Oceanography, Oregon State Behavior: Builds U-shaped tubes which University, Salem, OR. protrude from the mud (Chapman and 8. KIKUCHI, S., and M. MATSUMASA. Dorman 1975) and modify native habitats 1993. The osmoregulatory tissue (Pilgrim et al. 2013). around the afferent blood vessels of the coxal gills in the estuarine