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Eastern Pacific Expeditions of the New York Zoological Society. XXXVIII. Intertidal Brachygnathous Crabs from the West Coast of Tropical America with Special Reference to Ecology.

JOCELYN CRANE. Research Zoologist, Department of Tropical Research, New York Zoological Society.

Reprinted from ZOOLOGICA, Scientific Contribution of the New York Zoological Society, Vol. 32, Part 2, July 31, 1947. Crane: Brachygnathous Crabs from Tropical America 69

9. Eastern Pacific Expeditions of the New York Zoological Society. XXXVIII. Intertidal Brachygnathous Crabs from the West Coast of Tropical America with Special Reference to Ecology.1

JOCELYN CRANE. Research Zoologist, Department of Tropical Research, New York Zoological Society.

(Text-figures 1-3).

[This is the thirty-eighth of a series of papers Ozius perlatus Stimpson 81 Ozius tenuidactylus (Lockington) 81 dealing with the collections of the Eastern E iphia squamata Stimpson 81 Pacific Expeditions of the New York Zoological Eriphides hispida ( Stimpson ) 82 Society made under the direction of Dr. William Domecia hispida Eydoux & Souleyet 82 Trapezia cymodoce ferruginea Latreille 83 Beebe. The present paper is concerned princi­ Trapezia digitalis Latreille 83 pally with specimens taken on the Eastern Family Grapsidae 83 Pacific Zaca Expedition (1937-1938) ; for gen­ Grapsus grapsus ( Linn. ) 83 Geograpsus lividus ( Milne Edwards ) 84 eral data, see Zoologica, Vol. XXIII, No. 14, Goniopsis pulchra (Lockington) 85 pp. 278-298. A few were taken at Clarion I. on P':chygrapsus transversus (Gibbes) 85 the Templeton Crocker Expedition (1936), and Sesarma sulcatum Smith 86 Sesarma rhizophorae Rathbun 86 on subsequent trips to Panama and Ecuador Aratus pisonii (Milne Edwards) 86 made by the author in 1941 and 1944]. Habitat Zones 86 Concluding Remarks on Field Observations 90 CONTENTS. References Cited 93 Page Introduction 69 INTRODUCTION. Annotated List of Species 71 Family Majidae 71 This paper consists of three parts. The Eucinetops panamensis Rathbun 71 first is an annotated list of species of inter­ Acanthonyx petiverii Milne Edwards 71 Pelia pacifica A. Milne Edwards 71 tidal brachygnathous crabs taken between Thoe sulcata sulcata Stimpson 71 Cape San Lucas, Lower California, and Thoe sulcata panamensis Nobili, subsp. nov 71 Guayaquil, Ecuador, between 1937 and 1944, Herbstia tumida ( Stimpson ) 72 Pitho sexdentata Bell 72 with special reference to color in life and Anaptychus cornutus Stimpson 72 other field observations. Fifty-one species, Mithrax denticulatus Bell 73 Mithrax crcutti Rathbun 73 comprising more than 2,000 specimens are Mithrax pygmaeus Bell 73 recorded. These figures exclude 29 species Teleophrys cristulipes Stimpson 73 Mlcrophrys platysoma (Stimpson) 74 of Ocypodidae, the reports of which have Family Parthenopidae 74 already been published. Except as noted be­ Daldorfia garthi Glassell 74 low, the synonymy of Rathbun's mono­ Family Xanthidae 74 Carpilodes cinctimanus (White) 74 graphs is accepted (1918, 1925, 1930). In Actaea dovii Stimpson 74 the report, one new species {Metapocar­ Actaea sulcata Stimpson 74 Daira americana Stimpson 74 cinus concavatus) is proposed. One species Medaeus spinulifer (Rathbun) 75 is reduced to subspecific status {Thoe sul­ Cycloxanthops vittatus (Stimpson) 75 Leptodius taboganus Rathbun 75 cata panamensis). Mithrax areolatus is con­ Xanthodius sternberghii Stimpson 75 sidered a synonym of M. denticulatus, and Xanthodius stimpsoni (A. Milne Edwards) 77 Lophoxanthus lamellipes (Stimpson) 77 Xanthodius hebes of X. sternberghii. Metapocarcinus concavatus sp. nov 77 The second part discusses the habitats of Panopeus purpureus Lockington 79 Panopeus chilensis Milne Edwards & Lucas 79 these species and of the expeditions' Eurypanopeus planus (Smith) 79 ocypodids. Eurypanopeus transversus (Stimpson) 80 Eurytium tristani Rathbun 80 The paper concludes with some general re­ Micropanope xantusii (Stimpson) 80 marks on the field observations. Menippe frontalis A. Milne Edwards 80 Menippe obtusa Stimpson 80 In this report, the term "intertidal crabs" Pilumnus gonzalensis Rathbun 81 is used to embrace those species occurring Pilumnus pygmaeus Boone 81 Pilumnus xantusii Stimpson 81 typically in a habitat which is under tidal Heteractaea lunata (Milne Edwards & Lucas) .... 81 influence, so that the crabs are more or less Ozius verreauxii Saussure 81 amphibious. Rocky, sandy and muddy niches 1 Contribution No. 771, Department of Tropical Research, are included, as are those subject to moisten­ New York Zoological Society. ing by waters of various degrees of salinity. 70 Zoological New York Zoological Society [32: 9

CLARION ISL. TENACATITA B. MANZANILLO SIHUATANEJO ACAPULCO DULCE PORT ANGELES- PORT GUATULCO- SANTA CRUZ B.- TANGOLA-TANGOLA B. F O N SEC A

SAN JUAN DELSURJTÉ PORT PARKER —7 MURCIELAGO Br POTRERO GRANDE B.- PORT CULEBRA BRAXILITO B. PIEDRA BLANCA B GULF OF NICOYA

EASTERN PACI FIC E X P E D 1 T 1 0 N S NEW YORK » ZOOLOGICAL SOCIETY GA LAPAGOS IS. SHORE COLLECTING STATIONS

TEXT-FIG. 1. Shore collecting stations of the Eastern Pacific Expeditions of the New York Zoological Society.

In the delimitation, for ecological purposes, Gecarcinidae, although they occur on the of such a group of species, various difficulties fringes of both beach and mangrove areas; are naturally encountered, although in most several Sesarma which proved as typically cases there is no question as to the propriety fresh-water inhabitants as the Potamonidae, of including a given zone or species. The only although they also occurred in the upper ecologically questionable zone treated is that reaches of tidal streams; and all Plagusia, of Pocillopora coral; it is included because which, although rarely found in tidepools, most of the species inhabiting it occur also are characteristically oceanic. in definitely tidal zones, rather than in deeper The following papers have already been waters. In regard to taxonomic groups, it published on the brachyuran crabs of the was finally decided to exclude the following : Eastern Pacific Expeditions of the New York all the Portunidae, Goneplacidae and Pinno- Zoological Society: Glassell, 1936; Crane, theridae, in spite of the fact that species of 1937.1, 1937.2, 1940, 1941.1, 1941.2, 1943, these families were occasionally taken in 1944 (see "References Cited"). Those papers tidepools, coral, or in high-tide seines; the still to appear include reports on ocypodids 1947] Crane: Brachygnathous Crabs from Tropical America 71 from Ecuador, on the non-tidal brachygnaths relatively few examples, long flags of weed of the Eastern Pacific Zaca Expedition particles were attached to rostrum. One crab, ( 1937-1938), and on the non-brachygnathous ochre-colored, had several pale, central, crabs collected on the same trip. bryozoan-like markings. Eggs orange. In the following "Annotated List of Spe­ Range: Southern Florida to Brazil; cies," references are given to the type de­ Mexico to Chile; Galapagos. scription, to Rathbun's monograph, and to Pelia pacifica A. Milne Edwards, 1875, p. records which have appeared since the mon­ 73 ; Rathbun, 1925, p. 283. 26 specimens from ograph. The zone numbers following the Mexico (Acapulco), Nicaragua (Corinto), habitat description refer to the various types Costa Rica (Jasper I., Uvita) and Panama of habitat described in the section beginning (Honda). Clinging to underside of low-tide on p. 86. stones, in tidepools, and in Pocillopora coral ; I wish to express my thanks to Dr. Waldo once on orange seafan (Zones 3, 4, 5). Eggs L. Schmitt of the United States National in Jan., Feb., Mar. (Nie, C. R.). Museum and to Dr. John Garth and other Color at Uvita, on undersides of sponge- members of the staff of the Hancock Re­ and algae-grown stones : Bluish-gray above, search Foundation of the University of pile ochraceous yellow. Chelipeds: merus Southern California for their friendly co­ and manus translucent buff peppered with operation in giving me access to comparison black; carpus and chelae flame scarlet. Un- material in their respective collections. derparts buffy green. Eggs orange. General color in tidepools at Corinto : dark red. Many ANNOTATED LIST OF SPECIES. specimens from various localities were well FAMILY MAJIDAE. covered with hydroids (anteriorly only), Euclnetops panamensis Rathbun, 1923, p. sponges, algae and sand grains. 73 ; 1925, p. 87.19 specimens from Costa Rica Range: Manzanillo, Mexico, to Panama. (Port Parker, Piedra Blanca, Uvita) and T/ioe sulcata sulcata Stimpson, 1860, p. Panama (Honda). Usually in tidepools, 177; Rathbun, 1925, p. 349; Crane, 1937, p. rarely under low-tide stones (Zones 4, 3). 59. 23 specimens from Mexico (Clarion L, Eggs in Feb., Mar. (C.R.). Chamela, Tenacatita, Sihuatenejo). In tide- Color of 16 specimens from Piedra Blanca pools and Pocillopora coral (Zones 4, 5). found in single small patch of fine green Eggs in Nov., Dec. (mainland), May algae : Carapace and ambulatories forest (Clarion). Text-fig. 2B. green above; manus mottled forest green Range : Gulf of California and west coast and greenish-yellow; dactyls white; under- of Mexico to 0 axaca. parts of body entirely bluish-white striped T/ioe sulcata panamensis Nobili, subsp. nov. transversely with broken lines of purplish- blue; underside of ambulatories forest (Text-fig. 2A). green; bits of weed and sand grains at­ Synonymy : Thoe panamensis Nobili, 1901, tached to carapace and chelipeds; eggs p. 30; Rathbun, 1925, p. 351 and syn.; Finne- orange. Specimens from other localities also gan, 1931, p. 624. decorated with weed. 67 specimens from Nicaragua (Cardon I., Range: Gulf of California to Panama. at Corinto), Costa Rica (Port Parker, Cule- Acanthonyx petiverii Milne Edwards, bra, Piedra Blanca, Jasper I., Uvita) and 1834, p. 343; Rathbun, 1925, p. 142; Boone, Panama (Honda). Undersides of rocks and 1927, p. 137; Huit, 1938, p. 11; Garth, 1946, stones at extreme low-tide levels, in tidepools p. 376. 23 specimens from Nicaragua and in Pocillopora coral (Zones 3, 4, 5). Eggs (Corinto), and Costa Rica (Piedra Blanca). in Jan., Feb., Mar. (C. R. and Pan.). Among elongate algae growing either in The two species, sulcata, ranging south to tidepools or, rarely, on exposed, surf-beaten Oaxaca, and panamensis, known previously rocks (Zones 4, 1). Also occasionally found only from the Bay of Panama, have hereto­ below low-tide level. Eggs in Jan., Feb. (Nic, fore been distinguished by two characters: C. R.). first, by the development of the outer row Color ranges from bright lettuce green of excavations on the arm, which are well through ochre and brown to deep maroon, developed in sulcata and obsolete or obso­ depending entirely upon color of surround­ lescent in panamensis, and second, by the ing algae ; in one pool, the crab was found on spinulation of the upper margin of the am­ six or eight kinds of algae, all of different bulatory merus, which is strongly spinous in colors, so that extremes of variation were sulcata and only obscurely so in panamensis. found on crabs living within 6 inches of one Briefly, therefore, the northern form is more another ; the greenest ones lived on a kind of spinous and eroded. smooth sea lettuce, and were smoother, with Rathbun's suggestion that panamensis fewer tubercles, than the others. This varia­ may perhaps not be specifically distinct is tion in tubercles is well known, but the shown to be true by the present extensive matching of smoothness and color to back- series. Because of the variation in the de­ gi*ound has apparently not been recorded. In velopment of both the excavations and spines 72 Zoologica: New York Zoological Society [32: 9 in northern and southern forms, there the change is complete and abrupt. Addi­ seems no valid specific distinction. Were it tional specimens from the Cape San Lucas not for a sharp change in a detail of the region, examined in the Hancock collections, abdominal appendage at about the latitude show the same distinction in contrast to of Tehuantepec, the species should even be southern forms as do those from middle regarded as monotypic, although showing a Mexico. It is on this basis that the relegation tendency to form a geographical cline. of panamensis to the statue of subspecies is Even in the most northern, typical sul­ proposed. cata, the outer row of pits on the arm is com­ Both subspecies are similar in color and pletely developed only in the largest males, habit. They are dingers, and are especially less so in the largest females; in other ex­ to be found among yellow sponges growing amples, only two or three outer excavations on stones and dead corals well covered with are present and these are confined to the these and other animal and vegetable distal part of the arm. In some examples growths, at extreme low-tide levels, in tide- from Nicaragua, on the other hand, the pits pools and in Pocillopora coral. They are are so well developed that the specimens usually well decorated with the shells of could almost be referred to sulcata, were it Spirorbis-like polychaetes, bryozoans and not that the spinulation on the ambulatory other growths. Their basic color (Costa meri is very weak. In a series from Port Rica) is dull yellowish-brown, except for Parker, Costa Rica, the pits are so variable manus of chelipeds which is pinkish, and the that they are taxonomically useless, while dactyls which range from deep rose to bright there are traces of spinulation on the legs. orange, shading distally to white. All under­ In specimens from Jasper I., C. R., some ex­ pays white. Females are usually more amples have spines almost as strong as in brown, less yellow, than males; young typical northern sulcata; the rest of the (around 4 mm.) paler yellow than adults, Jasper series are typical panamensis. with manus violet, not pink; chelae even at this stage are bright orange. Range: Corinto, Nicaragua, to Panama. Herbstia tumida (Stimpson, 1871, p. 95) ; Rathbun, 1925, p. 299; Finnegan, 1931, p. 623; Crane, 1937, p. 59. 1 immature female from Panama (Honda). Previously known only from Mexico. On under side of stone at extreme low-tide level (Zone 3). Specimen compared with example in Hancock Founda­ tion which was identified by Rathbun, and with other southern material in the same institution, which has not yet been recorded. Pitho sexdentata Bell, 1835, p. 172; Rath­ bun, 1925, p. 367; Sivertsen, 1933, p. 11; Crane, 1937, p. 60; Garth, 1946, p. 387. 1 specimen from Costa Rica (Port Parker). Previously known from Cape San Lucas, the Gulf of California, Ecuador and the Gala­ pagos. On underside of stone at extreme low-tide level (Zone 3). Anaptychus cornutus Stimpson, 1860, p. 184 (56) ; Rathbun, 1925, p. 378. 40 speci­ B mens from Mexico (Chamela, Sihuatenejo), A Costa Rica (Port Parker, Culebra, Piedra TEXT-FIG. 2. Right abdominal appendages in Blanca, Jasper I., Ballenas, Uvita) and Pan­ subspecies of Thoe sulcata, postero-lateral ama (Honda). Under side of stones at ex­ views of distal halves. A. T. sulcata panamensis. treme low-tide level, in tidepools and in B. T. sulcata s. Pocillopora coral (Zones 3, 4, 5). Eggs in Nov. (Mex.), Jan., Feb., Mar. (C. R., Pan.). The only sharp distinction in any is the Color at Chamela, in tidepool: Olive green form of the abdominal appendage. In all overgrown with white bryozoans, green and specimens taken north of the Gulf of Tehuan­ purple sponges and algae. Eggs purplish- tepec, there is no subterminal spur on the black (ready to hatch). Specimens from all anterior inner surface; from Nicaragua localities typically covered with calcareous south a very distinct spur invariably occurs. algae, sponges, hydroids, bryozoans, ser- (We have no specimens from the intermedi­ pulids, barnacles and sand grains. ate region). The spur does not decrease grad­ The number of tubercles or lobes on the ually in size or prominence, from south central portion of the posterior crest varies northward, as would be the case in a cline; from six to eight ; often the lobes are so low 1947] Crane : 'Brachygnatfious Crabs from Tropical America 73 that the crests appear practically entire. An­ immature male from Nicaragua (Corinto). terolateral margins with lobes very variable, Clinging to ochre weed in tidepool, and some almost as spinous as in Mithrax. matching it perfectly in color (Zone 4). Rostrum and pre-ocular spines are apt to be Range: Mazatlan, Mexico, to Panama. broken. Mithrax pygmaeus Bell, 1835, p. 172; Range : Gulf of California to Panama. Rathbun, 1925, p. 406; Finnegan, 1931, p. Mithrax dentlculatus Bell, 1835, p. 172; 624; Huit, 1938, p. 12; Garth, 1946, p. 391. Rathbun, 1925, p. 428; Boone, 1927, p. 161; 4 specimens from Costa Rica (Port Parker, Garth, 1946, p. 395. Culebra). First records north of Panama. In Synonymy : Mithrax areolatus Lockington, Pocillopora coral (Zone 5). A few other 1876, p. 71 (9); Rathbun, 1925, p. 433; specimens, dredged in shallow water, will Crane, 1937, p. 48. be recorded in a future report. 86 specimens from Mexico (Chamela, Some examples tend to have the front Sihuatenejo, Guatulco, Tangola-Tangola), subtruncate instead of rounded. The spines, Costa Rica (Port Parker, Culebra, Piedra counting tubercles, may number 7 instead Blanca, Uvita) and Panama (Honda). On of 6. undersides of large stones at extreme low- Range: Costa Rica, Panama, Galapagos, tide levels, in tidepools among short weed Ecuador. and in Pocillopora coral (Zones 3, 4, 5). Eggs Te/eopArys cristulipes Stimpson, 1860, p. in Nov., Dec. (Mex.) ; Jan., Feb., Mar. 190 (62) ; Rathbun, 1925, p. 441; Finnegan, (C. R., Pan.). 1931, p. 625; Crane, 1937, p. 61; Glassell, Color variable, but in general olive green 1934, p. 453; Schmitt, 1939, p. 25; Garth, to olive brown above, sometimes mottled, 1946, p. 396. with hairs and underparts lighter. Notes Synonymy: T. diana Boone, 1927, p. 162; from various localities indicate this varia­ Sivertsen, 1934, p. 13; Huit, 1938, p. 12. bility: Chamela tidepools: Greenish with T. tumidus Rathbun, 1925, p. 442 (part. : dark brown mottlings anteriorly. Port Park­ the Galapagos specimen) ; Boone, 1927, p. er coral: Carapace mottled chocolate brown 166. * and dull olive green; eyes chocolate brown; 99 specimens from Mexico (Chamela, chelipeds and legs like carapace; hairs olive; Guatulco, Clarion I.), Costa Rica (Port distal half of chelae flesh pink; sternum and Parker, Culebra, Jasper I., Uvita) and maxillipeds plain olive ; abdomen white with Colombia (Gorgona I.). Always in Pocillo­ joints brownish; underside of ambulatories pora coral except for one specimen in a tide- greenish-white. Piedra Blanca, tidepools and pool and another at low-tide level in dead undersides of rocks at extreme low-tide level : pearl oyster (Zones 5, 4, 3). Entirely olive green to olive brown above, Color in general olivaceous. Almost all the with hairs yellowish-brown; underparts buf- crabs were naked except, rarely, for two or fy or greenish-white with joints of merus three tiny Spirorbis encrustations. One of cheliped bright orange; joints of ambula­ specimen was decorated with a few algae. tories yellowish ; chelae dark green tipped Garth (1946, p. 399 ff.) has clarified the with cream. Uvita coral: Like above, but distinctions between T. cristulipes and the upper side plain dark olive with branchial Peruvian T. tumidus, and commented on the sulcae white; young (ca. 4 mm. long) more variation in the two species. Our own series light brown than olive. In other localities support his conclusions : In our two Gorgona young were like adults. All eggs purple. examples, the crestiness and the anterior When groups of living specimens were ex­ tooth are more strongly developed than in amined, in trays, all clung to one another in more northern specimens, and there is a crest a ball, in lieu of weed. similar to that of tumidus on the posterior M. areolatus Lockington should be synony- part of the propodus. Comparison with speci­ mized with M. denticulatus. Our specimens mens of both tumidus and cristulipes in the vary in relative width, giving proportions Hancock collections, however, leaves no intermediate between the diagnostic char­ doubt that the Gorgona specimens show only acters for the two species. Also, if Locking­ normal variation. Both Garth and Finnegan ton and Kingsley omitted spines in their (1931, p. 625) noted that specimens of cris­ breadth measurements, the proportions of tulipes cracked from coral had the legs more areolatus would approach those of denticu­ cristate and the spines of the anterolateral latus. Finally, the equal or unequal advance margins better developed than those from of the antennal articles is not a reliable char­ shore. In our examples great variation is acter, since in the present series variation shown even though almost all were taken occurs on two sides of the same individual, from submerged corals. Even series of sim­ and in different specimens from the same ilar size from the same coral-head show con­ locality. siderable range. In the type series of T. di­ Range : San Diego, California, to Ecua­ ana Boone from the Galapagos, taken from dor. corals in 15 feet of water, the specimens Mithrax orcutti Rathbun, 1925, p. 397. 1 are all relatively smooth. 74 Zoologica: New York Zoological Society [32: 9

Range: Lower California to Colombia; Varying considerably in color, but eyes Galapagos. always bright red. Adults : carapace and legs Microphrys platysoma (Simpson, 1860, p. ranging from dull orange through brown 180); Rathbun, 1925, p. 497; Crane, 1937, to plum color ; underparts white except ptery- p. 63; Garth, 1946, p. 405. 7 specimens from gostomian region, merus of third maxilliped Mexico (Clarion I.), Costa Rica (Port Par­ and manus and dactyl of ambulatories which ker, Uvita) and Panama (Honda). Under are lavender ; chelae dark brown tipped with stones at low-tide level, in tidepools and in buff ; pile of carapace, legs and edges of ab­ Pocillopora coral (Zones 3, 4, 5). Specimens domen ochre. Young (around 5 mm.) always usually completely covered with vegetable with three dark red longitudinal bands al­ and animal growth. ternating with two white bands, the latter Range: Lower California to Ecuador; being broadest in the very young. Some­ Galapagos. times the three red bands are broken irreg­ ularly, so that a checkerboard-like carapace FAMILY PARTHENOPIDAE. results; legs all banded with dark red and Daldorfia garthi Glassell, 1940, p. 68 and white ; nodules in dark stripes raspberry red, syn. ; Garth, 1946, p. 412. 1 specimen from others white. One half-grown specimen was Costa Rica (Port Parker), a large, worn dull orange above with purplish legs. The male, taken under a rock at extreme low-tide color recorded by Rathbun of a Galapagos level (Zone 3). When this specimen was com­ specimen ("eleven orange-red stripes extend pared with material in the Hancock collec­ backward from frontal and antero-lateral tions from various localities, the following margins and converge posteriorly") and fig­ differences from the type description were ured by Garth was not seen on any of the found to be only normal variation: Pos- present specimens. Eggs dark purple. tero-lateral and posterior margins are not The crabs always remain well concealed. straight; spines on antero-lateral margin Bits of shell and sand cling to the pile of are smaller and simpler; meri of ambula­ the carapace and help make them inconspic­ tories are practically smooth, îacking spines uous. As they lie perfectly quiet in crevices on dorsal (anterior) side; the abdomen is in the coral and in tidepools, only their gleam­ sculptured somewhat differently. ing eyes, ranging in color from brilliant Range: Cape San Lucas, Lower Califor­ scarlet to vermilion, are visible. nia, to Colombia; Galapagos. Range: El Salvador to Ecuador; Galapa­ gos. FAMILY XANTHIDAE. Actaea sulcata Stimpson, 1860, p. 203; CarpUodes cinctimanus (White, 1847, p. Rathbun, 1930, p. 259; Finnegan, 1931, p. 336); Rathbun, 1930, p. 242; Crane, 1937, 632 ; Crane, 1937, p. 69 ; Garth, 1946, p. 434. p. 69; Garth, 1946, p. 427. 15 specimens from 8 specimens from Mexico (Clarion I., Ten- Mexico (Clarion I., Guatulco), Costa Rica acatita, Sihuatenejo, Guatulco) and Costa (Port Parker, Culebra, Jasper I.). In Pocil­ Rica (Port Parker, Jasper I.). In Pocillopora lopora coral (Zone 5). One ovigerous female coral; once under tidepool rocks (Zones 5, in Feb. from Jasper I. 4). One ovigerous female at Sihuatenejo in Color as given by Rathbun, Garth and Nov. Crane, except that general color is often Color at Tenacatita, whitish with tuber­ deep scarlet instead of light red, orange, or cles rose red except around eyes where dragon's blood red. Black band of male man- they are white. Cf. color of Gulf of Cali­ us never developed in specimens less than fornia specimens which were orange-red and 9 mm. long; also lacking in one male of 12.5 orange-red mottled with white (Crane, mm. Smallest examples in our mainland se­ 1937), and Galapagos specimens which were ries (around 5 mm.) are completely white "neutral red with bluish tinge" with pos­ above and below except for scarlet orange terior median nodules "yellowish white" chelipeds and ambulatories. Cf. Garth's Gal­ (Garth, 1946). apagos growth series. Range: Arena Bank, Gulf of California, Range : Arena Bank in Gulf of California to Colombia; Galapagos. to Costa Rica; Galapagos ; South Sea Islands ; Daira americana Stimpson, 1860, p. 212 Japan and Australia to Gulf of Aden. (84); Rathbun, 1930, p. 268; Crane, 1937, Actaea dovii Stimpson, 1871, p. 104; p. 70; Huit, 1938, p.12; Garth, 1946, p. 439. Boone, 1927, p. 203; Rathbun, 1930, p. 254; 40 specimens taken from Mexico (Clarion Finnegan, 1931, p. 632; Sivertsen, 1933, p. I., Chamela), Costa Rica (Port Parker, Cu­ 15; Schmitt, 1939, p. 25; Garth, 1946, p. 431. lebra, Uvita), Panama (Honda). In Pocil­ 77 specimens from Costa Rica (Port Parker, lopora coral; sometimes under low-tide Culebra, Piedra Blanca, Jasper I., Uvita), stones (Zones 5, 3). Eggs in Jan., Mar. Panama (Honda, Pearl Ids.). In tidepools (C. R.). (among weed and under stones) and in Po­ Color as in Crane, 1937, but abdomen often cillopora coral (Zones 4, 5). Eggs in Jan. tinged with purple instead of carmine. and Mar. (C. R., Pan.). Food: 6 stomachs from Port Parker: 1947] Crane : Brachygnathous Crabs from Tropical America 75

square bits of flat, brown algae, not macer­ tide levels on moderately protected shores; ated. more rarely, in tidepools (Zones 2, 3, 4). Range: Lower California to Ecuador; Eggs in Dec. (southern Mexico, Nicaragua), Galapagos. Jan. (Nia, C. R.), Feb., Mar. (C. R.), Apr. Medaeus spinuliter (Rathbun, 1898, p. (Pan., Col.). 585) ; 1930, p. 276; Finnegan, 1931, p. 643; The color varies irrespective of sex or Garth, 1946, p. 443. 2 specimens from Costa size, from black through dark greens, grays Rica (Jasper I.). In Pocillopora coral (Zone and brown to buff and white, blending with 5). Also occurs in deeper water. the substratum, often speckled or blotched. Range : Cape San Lucas, Lower Califor­ A well-marked phase is dark with median nia, to Costa Rica; Galapagos. pale stripe; this form occurs sporadically Cycloxanthops vittatus (Stimpson, 1860, in varying numbers in different populations, p. 206 (78) ) ; Boone, 1927, p. 197; Rathbun, and appears irrespective of substratum col­ 1930, p. 291 ; Sivertsen, 1933, p. 15. Garth, or. Ambulatories often banded distally with 1946, p. 445. 8 specimens from Mexico (Gua- purple and yellow. The faithful matching tulco, Tangola - Tangola) and Costa Rica of their environment, plus their habit of (Port Parker). Under rocks at extreme low- sheltering under stones, must give these tide levels and in Pocillopora coral (Zones crabs excellent protection, whether they are 3, 5). quiescent during low tide or actively feed­ Color variable : Port Parker : one specimen ing under water. When the background is uniformly pale tan; one white with a few homogeneous in color, the individuals of the black spots, a scarlet spot on cardiac region population usually vary little, except for the and one on each carpus of chelipeds. Fingers usual scattering of often conspicious indi­ dark brown. Tangola-Tangola : Carapace and viduals with a median white stripe. Where legs grayish-brown; chelae black; under­ the background varies because of different side pale except abdomen, which is like car­ colored pebbles, for instance, individuals apace with a white line down middle. Eggs within a radius of a few feet can be found dark brown. to match every pebble in the habitat, from Range : Cape San Lucas, Lower Califor­ whitest to darkest. nia, Mexico to Panama; Galapagos. The following field notes made in various Leptadlus taboganus Rathbun, 1912, p. 3; localities indicate the range of variation 1930, p. 304. 62 specimens from Costa Rica within typical populations : Guatulco : major­ (Port Parker, Piedra Blanca, Parida, Cedro ity ranging from pure white with a few I., Golfito), Panama (Honda) and Colombia brown spots through brown and gray spec­ (Gorgona I.). First records north of Pan­ kled mixtures to black marked with gray; ama. Under stones and rocks between tide a few completely dark gray above, chelae levels (Zones 2, 3). black, and legs purple with joints and dac­ General color greenish with underparts tyls yellow. Tangola-Tangola: Carapace and lighter. Cedro I.: Carapace and chelipeds chelipeds of large male olive green finely dark olive green; legs light olive, spotted stippled with dark brown ; ambulatories the with white; dactyls dark brown; underparts same, with merus-carpal joint bright yellow, pale olive gray; eggs black. Golfito: Green­ manus violet, dactyl straw; chelae grayish- ish-gray to greenish-brown above, speckled brown ; entire ventral surface except manus with dark blue; usually also a few white and dactyl of ambulatories white. Ovigerous spots on carapace ; chelae blue black to pale female similar, but all of ambulatories vi­ brown; lower half of manus buff y white to olet except merus joint and dactyl as above, light brown. All underparts blue marbled and abdomen speckled with olive on white. with white except pterygostomian region, Carapaces of other females close by: (1) which is buffy white. Cf. Schmitt's notes in black, mottled in median region with pure Rathbun, 1930, on Ecuador specimens ("sage white; (2) black with fine white mottlings; greenish in general, mottled with some light­ (3) white with black marblings; (4) white er traces of pea green."). marbled with chocolate ; ambulatories of all Range: Costa Rica to Ecuador. these phases more or less violet, with merus Xanthodius sternberghil Stimpson, 1859, joints and dactyls yellow. Isla Cardon, p. 52; Rathbun, 1930, p. 311 and synonymy. Corinto: Population in relatively exposed Synonymy: Xanthodius hebes Stimpson, position, mostly among dark rocks; major­ 1860, p. 208 (80) ; Rathbun, 1930, p. 313 ity dark brown, but when the stones are and synonymy. on sandy substratum, crabs often with one 165 specimens from Mexico (Sihuatenejo, or two median streaks or lines of spots,' Puerto Angeles, Guatulco, Tangola), Nic­ pure white, down middle of carapace, aragua (Corinto, San Juan del Sur), Costa especially on gastric region. Individuals also Rica (Port Parker, Piedra Blanca, Cedro, marbled greenish-buff with darker green, Ballenas, Uvita, Golfito), Panama (Honda) matching sand; this phase was especially and Colombia (Gorgona). Hundreds more common in the young of this population; seen but not collected. Under stones between chelae of young very pale brownish. Dark- 76 Zoological New York Zoological Society [32:9 est crabs in general occurred among dark depend on ocular comparison, they cannot rocks of the more exposed tidepools. Culebra be scientifically tabulated. However, in (seen, but not collected) : great majority- counts made with all the specimens spread matching dark volcanic sand which forms out and visible at once, on three successive substratum for stones; crabs of lighter days, the following average totals were ob­ shades occurring only in less protected re­ tained: hebes form 80, dubious 44, stern­ gions, where they were rare, matching the berghii form 41. Clear-cut hebes and stern­ tossed-up, water-worn coral. Piedra Blanca: berghii forms were rare. Age and sex ap­ 7 mm. male (none taken smaller than this) ; pear to have nothing to do with the appear­ carapace bluish-violet except for white pos- ance of the form and color variations do tero-lateral margin; legs dark. 10 mm. male: not link up with the morphological differ­ grayish-white except for ambulatories which ences. Unfortunately, at the time the col­ have carpus lavendar and dactyl straw. In lections were made the difficulties of the both young and adults the eye-stalks always taxonomy were not recognized, so that pop­ matched perfectly the circumorbital region ulations taken in slightly different niches of carapace. Cedro I. : Carapace of majority in the same bay—for example, from por­ green-black, but those with median white tions of the shore differing in water salin­ stripe more than usually common. Eggs ity—were not kept separate. From the field black. notes, however, it appears possible that the hebes form, which owes its morphological In structure as well as in color these crabs characteristics basically to heavier deposits proved to be exceedingly variable, as is to of mineral, represents merely a non-gene­ be expected with a widely distributed, suc­ tic response to environmental conditions. cessful species. Although they were the most The population containing the largest in­ abundant under-stone brachyurans on semi- dividuals of the entire collection consisted protected shores the entire length of west­ almost wholly of pure hebes-type individ­ ern Central America, the present report is uals, and was taken at Cardon Island, a the first to be published on a series gathered relatively exposed locality close to the open from many localities. Examination of these sea near Corinto, Nicaragua; the large size specimens and comparison with as yet un­ of these specimens is another example of recorded Hancock expedition examples from the frequently observed phenomenon that the same and more northern localities make in invertebrates large size and high salinity it apparent that Xanthodius hebes, recorded are linked. from Lower California, and X. sternberghii from Cape San Lucas and from Panama Behavior: Their observed behavior may to Peru, are not distinct species. X. hebes be divided into two distinct parts: the qui­ has been distinguished by: (1) the thicker, escent period, when the tide is out, and blunt, antero-lateral margin; (2) by the the active period of feeding during high edge of the front being invisible, not vis­ water. Their usual habitat at low tide is ible in a dorsal view; (3) by the narrower under stones, where they occur from the carapace (in which the length is contained highest to the lowest tidemarks. 1V2 instead of 1% times in the breath) and During low water, they are among the in the broader abdomen. It is perfectly true least mobile of the xanthids, and when first that some individuals show these differences exposed or disturbed, remain motionless, very distinctly, and in these, in addition, with the betraying, non-pebble-like legs correlated with the shape of the abdomen, curled under them. The second defense re­ the abdominal appendage of the adult male action, among adult and sub-adult males, is shorter, broader and more curved in hebes is the typical crab threat posture, with than in sternberghii. (A constant, corre­ wide-spread chelicerae and gaping chelae. sponding difference in the female genital Females and young never threaten, but passage could not, however, be discerned). maintain the curled-up possum-playing posi­ It is also true that the extreme sternberghii tion often for many minutes, even when form appears less often in our collections turned on their backs. made in Mexico than farther south. How­ When covered by water and undisturbed, ever, no basis whatever appears for rec­ they move about in the open, even in bright ognizing even a geographical cline, much sunlight, feeding on algae. Always, how­ less a subspecies or species. In the more ever, they remain near the refuge of a southern localities some populations were stone or crevice. composed altogether of one form, others of When observed in tidepools, their feed­ the second, and still others, the majority, ing habits can be studied in detail. The showed a preponderance of recognizable algae is picked with the minor cheliped, hebes, a few indecisive examples, and still the major being used for bracing and bal­ fewer sternberghii. The width of the cara­ ancing. This balancing is doubtless nec­ pace was found to be the most variable essary because most of the crab's weight character of all. Since the remaining char­ is anteriorly placed, in the broad front and acters cannot be accurately measured, but massive chelipeds; hence feeding with both 1947] Crane : Brachygnathous Crabs from Tropical America 77 claws would be impossible, in contrast to disturbed, they rouse and attempt to es­ Pachygrapsus, which has small chelipeds, cape more easily than do sternberghii. Usu­ and long legs holding up a moderate cara­ ally they are never exposed more than one- pace and which feeds using both claws half hour at each low tide. alternately. In Xanthodius the first and sec­ Young crabs are rougher than old ones. ond ambulatories do most of the work in Range: Mouth of Gulf of California to ordinary sidewise walking, the third helps, Ecuador. and the fourth, as well as both chelipeds, Lophoxanthus lamellipes (Stimpson, 1860, are suspended and do not touch the sub­ p. 205 (77)) ; Rathbun, 1930, p. 317. Garth, stratum except in climbing. The crabs feed 1946, p. 451. 65 specimens from Mexico at remarkable angles, often upsidedown, (Chamela, Tangola-Tangola), Costa Rica or standing on their hind legs and reach­ (Port Parker, Piedra Blanca, Uvita) ; Pan­ ing far above with their minor chelae for ama (Honda); Colombia (Gorgona). Un­ especially rich patches of algae. Although der stones exposed near low-tide level, in they feed only a few seconds in one spot, tidepools, and, rarely, in Pocillopora coral then move on an inch or two, most individ­ (Zones 3, 4, 5). Eggs in Dec. (Mex.), Jan., uals remain within a radius of about six Feb., Mar. (C. R.), Mar. (Pan.). inches. At Corinto, where observation con­ Color very variable. Some taken in var­ ditions were especially favorable, they paid ious localities, which agreed with -Rathbun's no attention to the little sand-colored blen- description, being slate-colored with red­ nies, which passed within an inch of them, dish-white chelipeds and antero-lateral mar­ but seemed to avoid the scarlet-legged her­ gins; more were entirely different. Local­ mit crabs, which fed on the same algae. ity examples : Chamela tidepool : Dark gray On the other hand, the two forms occasion­ except front and antero-lateral margins ally fed within an inch of each other. Often, which were cream. Port Parker: Some en­ in several localities a single grown male was tirely chestnut; some gray with white or found under a damp rock or in a pool with yellowish antero-lateral rim; some all gray; two or three ovigerous females and one or chelae entirely black. Piedra Blanca: Cara­ more young. None was ever seen feeding pace brown changing posteriorly to pur­ out of water, or crawling on exposed rocks, plish-brown ; frontal and antero-lateral mar­ yet they were found almost to extreme gins buff; chelipeds plain white with black high tidemarks, as well as near low tide. dactyls, their extreme tips light; ambula­ At Cardon Island, Corinto, where night ob­ tories dull lavender with greenish-yellow servations on tidepool animals were made, dactyls; entire underparts (except those not a single Xanthodius was seen after of white chelipeds) dull ochre. Uvita (un­ dark; if they are exclusively diurnal, the der tidepool stones) : color range about the feeding periods for the highest crabs must same as at Port Parker and Piedra Blanca. be very brief, unless migrations are made. Eggs always dark purple ; dark brown when Range: Lower California to Peru. about to hatch. (Cf. also Garth, 1946). Xanthodius stimpsoni (A. Milne-Edwards, Range: West coast of Mexico to Ecuador; 1879, p. 252) ; Rathbun, 1930, p. 315. 45 Galapagos. specimens from Mexico (Guatulco) and Costa Rica (Port Parker, Piedra Blanca, Metapocarcinus concavatus sp. nov. Uvita). Usually under encrusted stones ex­ (Text-fig. 3). posed near low-tide level; rarely in tide- Diagnosis: Front concave, single-edged; pools and Pocillopora coral (Zones 3, 4, 5). no tooth at base of major dactyl. Eggs in Dec. (Mex.), Jan., Mar. (C. R.). Description: Carapace moderately convex Color very variable. Immediate environ­ in the antero-posterior axis, naked, the re­ ment usually consists of stones encrusted gions scarcely marked, very finely granu­ with varicolored animal life, with which late. In the female there are four, short, crab in general blends. Adults, above, usu­ transverse lines of granules across the an­ ally entirely black, greenish-black or dark terior portion of the carapace : one pair on gray mottled with gray, light green or the antero-lateral regions, at the level of cream, but may be dark brown with antero­ the third antero-lateral teeth, the other lateral and frontal borders and all ambula­ pair, slightly further forward and inward, tories pinkish-tan; chelipeds may be con­ on the lateral medial areolations. These trastingly pale or, occasionally, entire crab granules are scarcely or not at all discern­ is buffy. Underparts usually pale, sometimes ible in the males. Antero-lateral margin mottled. Very young crabs tend to be paler with five teeth or lobes, all distinctly gran­ than adults. A single young was pinkish- ulate; the first, at orbital angle, small, nar­ tan with a median longitudinal white stripe row, blunt, the second broad, low, almost like that often found in sternberghii; che­ obsolete; the third broad and blunt, but lipeds chocolaté brown; ambulatories pink­ the most conspicious of the five; the fourth ish-tan. at widest part of carapace, smaller ; and the Although these crabs feign death when fifth almost obsolete, at the point where 78 Zoologica: New York Zoological Society [32: 9

B c TEXT-FIG. 3. Metapocarcinus concavatus. A. holotype, dorsal view. B. major cheliped of holotype, external view. C. carapace outline of male paratype. the marginal crest curves inward. The teeth duced, the inner distal edge broadly oblique tend to be noticeably asymmetrical on the and concave. Chelipeds and legs unarmed two sides of each of the three crabs ; in the and naked, except for pile on dorsal (ante­ juvenile male, the first and second lobes rior) edges of ambulatory coxae, ischia and are better developed than in the others. basal two-thirds of merus, and on ventral Front very prominent, edge rather thick, edges of feet. Chelipeds moderately un­ but clearly only single-edged, granulate; equal and massive, smooth except for mi­ it is concave, slightly sinuous, with a dis­ croscopic granulations. Carpus with a blunt tinct median notch. Orbit with two closed tooth at inner angle. Palms inflated; fin­ fissures near outer upper edge; no notice­ gers gradually tapering, acuminate, with able lobe at middle of lower margin; in­ four blunt teeth in distal half of each chela; ner lower angle a well-developed tooth which no tooth at base of prehensile edge of ma­ projects slightly beyond end of basal ar­ jor dactyl; third to fifth segments of ab­ ticle of antenna; eyes filling orbit. Merus domen fused. Basal two-thirds of chelae of outer maxillipeds about as broad as is­ dark, the dark color of pollex continued chium, the distal edge transverse, slightly slightly on palm. sinuous, the outer angle prominently pro­ Color in Life: Male paratype from light 1947] Crane : Brachygnathous Crabs from Tropical America 79

brown seaweed, in tidepool at Piedra Blan- Ballenas, Golfito) and Ecuador (Puerto Bo­ ca: Carapace cream-colored; postero-lateral livar). Eggs in late April at Puerto Bolivar. surfaces above bases of legs black, as re­ In stony mud on edges of mangrove swamps corded for M. truncatus by Stimpson (1860, and open mudflats (Zones 6, 7). p. 216 [88]). Chelipeds and ambulatories Range: Mexico to Peru. chocolate brown, except for pale dactyls; Panopeus chilensis Milne Edwards & chelae brownish-black, except for tips which Lucas, 1843, p. 16; Rathbun, 1930, p. 346. are pale. Underparts pale buffy brown. Aft­ 21 specimens from Nicaragua (Corinto: er nine years in alcohol, all of the color, Castenones lagoon) and Costa Rica (Cule­ except that of the cl^elae, has faded to bra). Eggs in Jan. at Culebra. In stony mud creamy white. on edge of lagoon (Zone 7). Measurements in mm. : Male holotype Range: Mexico to Chile. length 5.6, breath 6.1; female paratype, Eurypanopeus planus (Smith 1869, p. length 6, breath 6.7, male paratype, length 283); Boone, 1927, p. 212, 1929, p. 571; 4.8, breath 5.2. Rathbun, 1930, p. 420. 121 specimens from Range: The three known specimens were Nicaragua (near Potosi in G. of Fonseca, taken from Fumarole Shore, El Salvador Cardon I. at Corinto, San Juan del Sur) ; (northern) side of Gulf of Fonseca and Costa Rica (Port Parker, Piedra Blanca, from Piedra Blanca, Costa Rica. Cedro I., Uvita, Golfito), Panama (Honda), Habitat: The male paratype was in a Colombia (Gorgona). Eggs in Jan. (Nic), brown, sargassum-like weed. Only this single Mar. (C.R., Col.). Under stones at junction specimen was taken in more than six care­ of sandy beaches and stony shores, where fully examined pailsful from the same tide- fairly large, but movable stones are strewn pool (Zone 4). on sand between mean high and mean low Discussion : The proposed new species dif­ tide (Zone 2). This is exactly the habitat fers from Metapocarcinus truncatus Stimp­ occupied by Uca panamensis, rather than son, 1860, as follows:— that of Xanthodius sternberghii, which is 1. The front is angularly concave and under stones at similar tide levels, but on a slightly sinuous, not truncate. rocky, not sandy, substratum. 2. The lateral teeth are somewhat less ob­ Color range in Central America agrees scure, particularly the third which is well well with that recorded by Schmitt (in developed. Rathbun) for Ecuadorian specimens. In our 3. The front is not double-edged. series, the light dots on the carapace were 4. There is no shallow lobe at the middle not always present, and, when there, were of the lower margin. almost white, no matter what the ground 5. The basal antennal article does not color; they were invariably confined to pos­ reach quite as far forward as the inner terior part of carapace. Very young crabs, suborbital tooth. 7 mm. or less in length, were usually plain 6. The merus of the outer maxillipeds is brown with dead white chelipeds except for scarcely or not at all narrower than the purple or brown white-tipped fingers. The ischium, its distal margin not oblique, its purple cast of the chelipeds develops at distal outer angle quite sharply produced, various ages, the smallest in which it occurs not arcuate, the distal inner margin decid­ measuring 7.5 mm. In this specimen both edly excavate instead of slightly notched. chilipeds were entirely light blue. No sexual 7. The dorsal edges of coxae, ischia, and color dimorphism was noted. Eggs black. basal two-thirds of meri of all ambulatories A single large male was occasionally are pilous. found with a single ovigerous female under 8. There is no trace of a tooth at base of the same rock, or with two ovigerous fe­ prehensile edge of dactyl of major cheliped. males. Have never seen more than one adult 9. Sixth abdominal segment of immature made under one stone, although young ones female not widening distally. may be present. When disturbed, adult males Material: Male holotype, Department of threaten with chelipeds and chelae wide­ Tropical Research, No. 37,675, Fumarole spread, holding them motionless, with the Shore, northern side of Gulf of Fonseca, El white underparts very conspicuous. They do Salvador, December, 1937; female paratype, not move for at least 10 minutes, even when No. 37,675a, same locality, same date as the disturbing human being promptly goes holotype; male paratype, No. 38,178, Piedra far down the beach behind rocks and out of Blanca, Costa Rica, February 4, 1938. The their sight. The females and young show no types are deposited in the collections of the threatening action whatsoever, and merely Department of Tropical Research, New York lie quietly, wherever put. Fourteen stomachs Zoological Society. contained the following: algae of various Panopeus purpureas Lockington 1876 kinds, worm spicules, remains of a bright (1877), p. 101 (7); Rathbun, 1930, p. 344. red worm, amphipods, unrecognizable or­ 14 specimens from Costa Rica (Culebra, ganic detritus, and sand grains. Those speci- 80 Zoological New York Zoological Society [32: 9

mens killed toward the end of a low tide 1929, p. 570. 6 specimens from El Salvador, period were always empty. This fact, com­ in Gulf of Fonseca (Fumarole Beach and bined with their complete quiescence during Concharita I.). First record north of Nica­ low tide, makes it probable that they feed ragua. 1 female ovigerous (Dec). Under under water. They are always found half dark volcanic stones (Zone 2). buried in a form under, or in the shelter of, General color brownish or grayish-purple, a rock; it seems likely that they do not dig or purplish-brown (nearest in Ridgway: this deliberately since there is never any dark heliotrope slate) ; no trace of the red trace of claw marks, but that they settle present in Rathbun's preserved specimen. into positions before the tide recedes and Underparts buffy yellow. Mouthparts allow the draining sand to harden around patched with violet. Upper outer half of them. manus veined with buffy; lower half buff Five specimens (Nos. 3834, 3860 and washed with violet; chelae black, except for 38164, from San Juan del Sur, Port Parker buff bases of both fingers. and Piedra Blanca) are infested with Sac- These large crabs look amazingly like lava culina. stones. When disturbed they grip stones Range: Gulf of California to Ecuador. tenaciously with their ambulatories and box Eurypanopeus transversus (Stimpson, with their open chelae. They can maintain 1860, p. 210 (82)) ; Rathbun, 1930, p. 407; position remarkably well against constant Garth, 1946, p. 455. Ill specimens from tugging and, when possible seize the human Costa Rica (Port Parker, Culebra, Ballenas, intruder's fingers and hang on like bull­ Golfito) and Ecuador (Puerto Bolivar) ; dogs, shedding their chelipeds less readily many more seen than collected. Eggs in Jan., than any other crab with which I am ac­ Mar., (C.R.) ; April (Ecuador). Under quainted. They will not come out of their stones in the following localities : in gravelly niches to attack and do not even run away mud, mud shores of bays and lagoons, among except when greatly disturbed on open mangrove roots near high-tide mark, and on ground. When annoyed they stridulate with edges of open mud flats. (Zones 6, 7, 8). the ridges of the manus rubbed squeakily Color: Ranging irrespective of locality against the underside of the carapace, chiefly from almost white to almost bla,ck, but most beneath the third lateral lobe; the tubercles typical coloring as follows: Olive marbled of this region described by Rathbun, how­ with dark blue or black above ; fingers black ever, are not well developed in our examples. tipped with white; underparts olive buff. The sound produced is like the high cry of Range: West coast of Mexico to Peru; a distant bird and is heard only when a crab Galapagos. is almost caught. It appears likely that Eurytium tristani Rathbun, 1906, p. 100; these methods of defense are quite effective 1930, p. 425. 43 specimens from Nicaragua against natural enemies such as shore-birds (Castenones lagoon at Corinto), Costa Rica and crab-eating raccoons. (Culebra, Ballenas, Golfito), Ecuador Range: Nicaragua to Peru. (Puerto Bolivar). First record north of Menippe obtusa Stimpson, 1859, p. 53 (7) ; Costa Rica. Among mangroves and on edges Rathbun, 1930, p. 478, Sivertsen, 1934, p. of mudflats (Zones 6, 7). 16. 5 specimens from Nicaragua (Cardon I. General color dark brown ; upper surface at Corinto). All in permanent fidepools of chelipeds violet; of finger deep red. (Zone 4). First record north of Costa Rica. Range : Nicaragua to Peru. All specimens taken were large females (35- Micropanope xantusli (Stimpson, 1871, 43 mm.) ; many more, both sexes, seen but p. 105^ [15]) ; Rathbun, 1930, p. 438; Crane, not captured. 1937, p. 72; Garth, 1946, p. 457, and syno­ Color in daylight, in air, brown to apricot nymy. 85 specimens from Mexico (Clarion orange. At night, under water, carapace and I., Sihuatenejo, Acapulco) and Costa Rica upper surface of chelipeds very dark green, (Port Parker, Culebra, Jasper I.). First rec­ almost greenish-black. Outer chelipeds, un­ ords between Mexico and Galapagos. Eggs derside of carapace and ambulatories dull in Jan. at Port Parker. Always in Pocillo- violet, the chelipeds speckled with blackish. pora coral (Zone 5), except for 3 young Chelae brownish-black, teeth and tips white. found at Port Parker in algae-covered stones Sternum and abdomen creamy blotched ir­ among mangroves near low-tide level. regularly with violet; hair on distal seg­ Color variable, but majority dark red ments of ambulatories dull green ; posterior mottled with lighter and darker. Sulci on half of carapace sometimes also tinged with major cheliped of adult males may be almost violet. Eyes red. Inner side of merus and lacking. carpal joints of chelipeds strawberry red. Range: Clarion Island; Cape San Lucas, Although doubtless common locally, these Lower California to Costa Rica; Galapagos. crabs are individually hermits, and are very Menippe frontalis A. Milne Edwards, retiring both night and day. Neither stridu­ 1879, p. 264; Rathbun, 1930, p. 477. Syno­ lation nor threat posture was observed. Un­ nymy: Eurypanopeus purpureus, Boone, like M. frontalis, obtusa spends its entire 1947] Crane : Brachygnathous Crabs from Tropical America 81

life under water in the crevices between buffy-orange. A Guatulco specimen has the immovable rocks in tidepools. At night one anterior third of carapace tinged with vio­ large female went after a chiton in a fish let. Boone records bandings of coral at meral trap she could not enter. When baited with and carpal joints of ambulatories in the a free chiton, she pulled it out of sight twice Galapagos ; these were found on few Central —once in daylight, once at night. This par­ American specimens, where they were repre­ ticular crab was finally caught by attracting sented by bright orange at joints of all legs her to the middle of a pool with a third and the entire length of the antennae. chiton, at night, and by then jumping in and Young, plain light brown; very young al­ seizing her just as she was starting to pull most white. away. Range: Lower California to Ecuador; Range: Pacific coast of Nicaragua to Galapagos. Panama. Ozius perlatus Stimpson, 1860, p. 211 Pilumnus gonialensis Rathbun, 1893, p. (83); Boone, 1927, p. 228; Rathbun, 1930, 240; 1930, p. 505. 3 specimens from Mexico p. 543; Sivertsen, 1934, p. 17; Schmitt, (Tenacatita). First record south of Gulf of 1939, p. 25; Garth, 1946, p. 477. 11 speci­ California. Among tidepool rocks (Zone 4). mens from Mexico (Tangola-Tangola), Grayish-brown. Nicaragua (Cardon I. at Corinto, San Juan Pilumnus pygmaeus Boone, 1927, p. 221 ; del Sur), and Costa Rica (Jasper I.). Under Rathbun, 1930, p. 515; Garth, 1946, p. 472. stones near low tide (Zone 3). 3 specimens from Costa Rica (Port Parker, Carapace and chelipeds rose red; chelae Culebra). Eggs in January. From weed in ranging from very pale to dark brown. Pos­ tidepools and on undersides of overgrown terior part of carapace sometimes apricot rocks, close' to low tide (Zones 3, 4). Pre­ buff. Sternum buff. Abdomen apricot buff viously known only from the Galapagos. to rose red. Ambulatories rose red above, Pilumnus xanfusii Stimpson, 1860, p. 213; paler pinkish below. Dactyls straw colored. Rathbun, 1930, p. 486; Garth, 1946, p. 471. Ventral side of carapace in narrow rim just 2 specimens from Mexico (Sihuatenejo) and under antero-lateral margin, rose red like Costa Rica (Culebra). In PocUlopora coral carapace. Cf. coloring in Galapagos (Garth, (Zone 5). Dr. J. S. Garth kindly identi­ 1946). fied the Culebra specimen for me. The speci­ These crabs, conspicuously colored to hu­ men from the Galapagos figured by Boone, man eyes, are more active when their stones 1927, p. 237, fig. 87B, as Eriphides hispida are overturned than are other sub-rock yg. should be referred to this species. Pre­ xanthids of the region. Often a number viously recorded only from Cape San Lucas occur together under single stones. and the Galapagos. Range: Cape San Lucas, Lower Califor­ Heteractaea lunata (Milne Edwards & nia, to Ecuador; Galapagos. Lucas, 1843, p. 20) ; Rathbun, 1930, p. 532. Ozius tenuidactylus (Lockington, 1877, Finnegan 1931, p. 644; Crane, 1937, p. 72. p. 98); Glassell, 1935, p. 104; Garth, 1946, Not Boone, 1930, photo A, p. 127. 35 speci­ p. 479 and synonymy. O. agassizii, Rathbun, mens from Mexico (Acapulco, Guatulco), 1930, p. 544. 38 specimens from Mexico Costa Rica (Port Parker, Culebra, Jasper), (Guatulco, Tangola-Tangola, Tenacatita), Colombia (Gorgona). Eggs in Jan. (Mexi­ Nicaragua (Cardon I. at Corinto), Costa co), Jan., Feb. (Costa Rica), Mar. (Colom­ Rica (Port Parker, Piedra Blanca, Culebra, bia). Our specimens were only found in Cedro I., Ballenas, Golfito), Panama (Hon­ PocUlopora coral (Zone 5) ; Rathbun reports da) and Colombia (Gorgona). Eggs in Feb. specimens also from low tide rocks (Zone 3). and Mar. (C.R. and Col.). Under stones near Range: San Diego, California (Faxon) low-tide mark in tidepools (Zones 3, 4). to Chile. Reddish-brown or purplish to deep ma­ Ozius verreauxii Saussure, 1853, p. 359; roon, slightly paler beneath. Eyes bright red. Boone, 1927, p. 223; 1929, p. 573; Rathbun, Manus and dactyls of ambulatories covered 1930, p. 540; Sivertsen, 1934, p. 17, Garth, with olive pile; chelae dark brown with 1946, p. 476. 35 specimens from Mexico white tips and teeth on major dactyl. Very (Puerto Angeles, Guatulco, Tangola-Tan- young crabs (just under 5 mm.) pale brick gola), Nicaragua (Cardon I. at Corinto, San red all over, lighter beneath; chelae lighter Juan del Sur), Costa Rica (Port Parker, brown than in adult. Eggs purple to pur­ Golfito) and Colombia (Gorgona). 1 oviger- plish-black. ous female taken at Golfito in March. Under Range: Gulf of California to Ecuador; stones near low tide and in tidepools (Zones Galapagos. 3,4). Eriphia squameta Stimpson, 1859, p. 56 Color pale olive buff to slate gray or (10) ; Boone, 1927, p. 231, 1929, p. 575, chocolate brown except chelae, which are 1930, p. 143; Rathbun, 1930, p. 550; Huit, dark brown to black, three distal segments 1938, p. 13; Garth, 1946, p. 483. 35 speci­ of ambulatories which are olive brown, and mens from Nicaragua (near Potosi R., Car- sternum and abdomen which are buff to don I. at Corinto), Costa Rica (Port Parker, 82 Zoologica: New York Zoological Society [32:9

Piedra Blanca, Ballenas, Uvita, Golfito), grapsus transversus and Xanthodius stern- Panama (Honda) and Colombia (Gorgona). berghii in general abundance. The young do Under stones from mean low to high-tide not threaten, but simply run away. The marks, and, more rarely, in tidepools (Zones adults, too, are surprisingly fast out of 2, 4). Once under mangrove root by mud water, when their stones are overturned, flat (Zone 6). Eggs in Jan. and Feb. (Nic, and are next to Pachygrapsus and Grapsus C.R.), April (Col). in speed, although none can compare with General color dark but variable, ranging Ocypode. from slate gray through dark grayish-green Range: Gulf of California to Peru; Gala­ to brown or black ; often brownish or black­ pagos. ish mottled with greenish, or dark blue, Eriphides hispida (Stimpson, 1860, p. 218 blending admirably with algae in tidepool. (90) ) ; Boone, 1927, p. 236, not fig. 87B, Chelipeds like carapace, but fingers and p. 145; Rathbun, 1930, p. 552; Sivertsen, ocular spines bright, ranging from burnt 1934, p. 18; Schmitt, 1939, p. 25; Garth, sienna to scarlet orange (Ridgway)—the 1946, p. 487. 8 specimens from Nicaragua latter shade the exact color of a red sponge (Cardon I. at Corinto), Costa Rica (Port that also grows in tidepool crannies, usually Parker, Jasper I.), Panama (Pearl Islands). in small, longitudinal patches. Ambulatories Surf rocks, low down (Zone 1). Eggs in Feb. banded with white or cream and purple, (C.R.). dark blue or brown. Underparts, and lower Color purplish-brown above, rufous orange proximal part of manus and carpus cream. beneath; cheae bright rufous orange; hairs Often two narrow violet stripes extend down black; eggs bright scarlet. Young, around two-thirds of abdomen. Eyes olive green 20 mm. long, like adults in color. with brown centers. Eggs dark wine colored. On the outer surf rocks this species takes Young (under 6 mm.) like adults, but the place of its cousin, Eriphia squamata. lighter. The burr-like bodies of the crabs stick tightly This crab is decidedly amphibious. I have in rock depressions and crevices close to low- seen it feeding both underwater on a tide mark when the tide is out, but when mollusk in a tidepool, and at night, out of the water covers them they swim freely in water, on tube worms. In day time I have the outermost pools. They have tremendous only once seen it in the open out of water clinging strength, most of the gripping be­ (though it frequently lies concealed under ing done with the middle two pairs of am­ stones at low tide). This individual was bulatories, and they do not shed the cheli­ scrambling on top of an exposed rock, but peds easily. They are rather solitary, al­ it had apparently been startled by a Grapsus though where one is found another usually out of its moist cranny or pool. All others occurs within a few feet. They appear to were either well hidden or submerged. Saw stay near low-water levels even when the one feeding in a submerged cranny holding tide is high; that is, unlike Grapsus, they do what looked like a piece of mollusk in both not progress with the rising water. Al­ claws and nibbling off it. Contents of 12 though most of the feeding is almost cer­ stomachs : Chiefly animal matter with some tainly done underwater, I have seen several algae: (1) tiny, banded thread-algae, amphi- feeding in the air on serpulid worms in pods, 10 mm. hairy pink annelid with re­ tubes. Dr. Beebe (1924, p. 131) suggests mains of hard tube, in only two pieces; (2) that the Galapagos representatives of the 1 megalops; (3) at least 3 megalopa and a species may dispossess the sea-urchin mak­ few sand grains; (4) sand containing scum­ ers of hollows in the lava. Unmistakable re­ like algae and a minute worm; (5) common mains of a sea-urchin's mouthparts were red and black tidepool hermit crab (no found in the stomach of a large female from shell) ; (6) tiny snails, mussels, worms, Corinto, along with sand and several algae amphipods; (7) bits of algae and unrecog­ fragments. Four other stomachs held no nizable animal matter; (8-12) stomachs recognizable material except sand. These with thread or S ar g as sum-like algae in crabs often let themselves be literally torn bits; 6 other stomachs were empty. to pieces rather than loose their foothold. The first action of these crabs when at­ Our mainland experience corresponds to tacked is to retreat. Their sight is relatively that of Dr. Garth, who speaks of the vise­ good : a moderate-sized male saw my fingers like grip of their powerful nippers in the coming through the water 6 inches away, Galapagos. and backed repeatedly out of reach, reap­ Range : West coast of Nicaragua to Pana­ pearing each time in the opening of its ma; Galapagos. This is the first record north cranny within one minute. Both males and of Costa Rica. females occasionally threaten with outspread Domeeia hispida Eydoux and Souleyet, chelipeds, but only when actively disturbed 1842, p. 235 ; Rathbun, 1930, p. 554 ; Finne- and retreat is impossible. The species is gan, 1931, p. 647; Crane, 1937, p. 73; Garth, exceedingly common in tidepools and mid- 1946, p. 489. 107 specimens from Mexico- tide stony zones, and ranks next to Pachy- (Clarion I., Guatulco, Sihuatenejo, Acapul-$ 1947] Crane: Brachygnathous Crabs from Tropical America 83

co), Costa Rica (Jasper, Uvita), Panama mimic the dead coral at the base of the (Honda), Colombia (Gorgona). Always, on head, are inconspicuously translucent, or this coast, taken in Pocillopora coral (Zone match the live corals' browns and ochres. 5). Eggs in Nov., Dec, May (Mexico), Mar. Furthermore, the shrimps and Trapezia are (Colombia). Carapace mottled brown and the only ones in the living part which do white, spines blackish. (Cf. VerrilPs ac­ not loosen their hold when bothered. Since count of Atlantic specimens : "Light yellow­ the majority of the coral heads live in water ish red, front darker; spines blackish. so shallow that the red rays have not yet Among sponges and branches of corals, and been much weakened, it is possible that in holes of dead corals and stones"). Trapezia is warningly colored. Range: South Carolina Brazil, eastern Experiments should be performed, feed­ Atlantic, Indian and Pacific Oceans to ing Trapezia and protectively colored crabs American Coast; Gulf of California to Co­ from the same environment, to such pre­ lombia ; Galapagos. sumably natural enemies as scorpaenids and Trapezia cymodoce ferruginea Latreille, hermit crabs. Whether the red is actually 1825, p. 695; Boone, 1928, p. 240; Rathbun, a warning color, or whether it has developed 1930, p. 557; Finnegan, 1931, p. 645; Crane, unchecked merely because of Trapezia's 1937, p. 73; Huit, 1938, p. 13; Garth, 1946, adoption of a well-protected niche, the crab p. 491. 778 specimens preserved from Mexi­ is certainly amazingly successful; it may be co (Clarion I., Acapulco, Guatulco, Sihua- that its numbers are kept down only by tenejo), Costa Rica (Culebra, Port Parker, destruction in the larval stages. Jasper I., Uvita), Panama (Honda). A ma­ Range: From Clarion Island and Gulf of jority of the females were ovigerous in every California to Colombia and the Galapagos; lot examined; from the data now at hand, Red Sea to Indo-Pacific area. therefore (incl. Crane, 1937), this species Trapezia digitalis Latreille, 1825, p. 696; is breeding in the northern part of its eas­ Rathbun, 1930, p. 559; Crane, 1937, p. 73; tern Pacific range, that is, in Mexico and Garth, 1946, p. 493. 110 specimens from Clarion I., at least from November to May, Mexico (Clarion I., Sihuatenejo), Costa and in the southern part, between Costa Rica (Uvita), Panama (Honda). The re­ Rica and Gorgona Island, at least from marks about breeding seasons in Trapezia January through March. On this coast the cymodoce ferruginea apply equally to this species was never taken except in living species. Like it, too, it occurs only in Pocillo­ Pocillopora coral (Zone 5) where it is the pora, at least in the eastern Pacific (Zone 5). most typical and abundant single species, Color on this coast always rich chocolate not only of crabs but of all macroscopic in­ brown to chestnut brown above, except for vertebrates. Even the smallest heads, mea­ the palms and dactyls of the ambulatories, suring less than a foot in diameter, have at which are usually bright chestnut red (cf. least one pair—usually an adult male and Rathbun's quotation of bright color descrip­ ovigerous female—clinging far inside. tions). In the very young, the anterior part Color scarlet to scarlet orange, as de­ of the carapace darkens first. scribed by Rathbun and Crane. Chelae are Range: Southern part of Gulf of Califor­ never black, dark brown at most, paler in nia to Panama; Red Sea to Indo-Pacific young. Very young crabs (around 5 mm. in region. length) are pale pumpkin orange, instead of scarlet or scarlet orange. Large males are FAMILY GRAPSIDAE. decidedly the brightest of all. Grapsus grapsus (Linn., 1758, p. 630) ; This species seems almost without ques­ Rathbun, 1918, p. 227; Boone, 1929, p. 577, tion to be the pattern for a case of crab- 1930, p. 203; Sivertsen, 1934, p. 18; Crane, shrimp mimicry. The shrimp (Crangon ven- 1937, p. 77; Garth, 1946, p. 504. 5 specimens trosus) is always less numerous, although preserved from Mexico (Banderas Bay), as typical of the Pocillopora habitat as is Nicaragua (San Juan del Sur) and Colom­ Trapezia. Its scarlet and black color matches bia (Gorgona I.). The species was recog­ the crab's structures. The shrimp always nized or collected and examined, but not has the carapace sideways in the coral, with saved, at the following localities: Mexico the cheliped folded out of sight; the crab (San Benito I., Cape San Lucas, Chamela sits frontways, the dark-tipped chelae folded Bay, Tenacatita Bay, Manzanillo, Sihuate­ in front of it. The true eye of the shrimp nejo, Tangola-Tangola, Acapulco, Dulce and one of the paired black spots over the River, Port Angeles) ; El Salvador (La Li- first abdominal segment represent the crab's bertad, Gulf of Fonseca), Nicaragua (Co- eyes. The black median stripe of the cara­ rinto), Costa Rica (Port Parker, Murcielago pace resembles the dark chelae of the crab Bay, Potrero Grande, Culebra, Braxilito, folded in front of it. Except for the shrimp, Piedra Blanca, Uvita, Golfito, Parida I.) ; and Carpilodes cinctimanus, Trapezia alone Panama (Coiba I., Bahia Honda, Balboa). of the coral crustaceans is brilliantly, not Ovigerous females were common in all lo­ protectively, colored. All the others either calities during the observation period (No- 84 Zoological New York Zoological Society [32:9

vember to April). The species is usually- that these crabs are also scavengers. Sev­ found only on large rocks exposed to surf eral times I have seen individuals eating and spray (Zone 1), occurring very rarely dead fish and insects, and once a Grapsus in protected harbors. At night it sleeps out seizing and eating a live dytiscid beetle. For of range of the tide, but during the day, an account of Galapagos specimens catching keeps always just above it. ticks on iguanas and eating martins, see Along the tropical coast of the eastern Beebe, 1924, pp. 93 and 121, or Boone, 1927, Pacific, this crab is midway in coloration p. 246 ff. between the dark phase of the Atlantic, and Forty stomachs were examined with the the stage found in the Galapagos where ap­ following results: Practically all contained parently all the adults, male and female, are fine rock algae, usually more or less mixed bright scarlet. In the present range, where with sand, such as is found washed up large colonies were observed all along the around the bases of the algae. coast, only rare, fully adult males are red­ Ten stomachs contained one or more of dish, and these are usually chestnut. the following: bryozoans, tiny mussels, bar­ Throughout the winter and spring, red nacles, hydroids. males (always more than 60 mm. long) The chief enemies in many localities are numbered not more than 1 in 50 to 100. The doubtless nocturnal crab-eating raccoons; exact proportion of adult males to adult twice raccoon tracks were found beside females was not obtained, but at a conserva­ Grapsus remains. Once a grackle was seen tive estimate there were 10 grown females to seize a crab, having stalked it from to one male noticeably red in color. Males around a projecting rock. Surf fishes must which do show red never have the overall often catch unwary crabs that are washed scarlet developed in the Galapagos. A 72 into the sea. mm. specimen from San Benito I. had the Range : Tropical and subtropical shores of - carapace chestnut brown, and sternum stria- America and of the eastern Atlantic. The tions paler; legs and chelipeds were bright subspecies G. grapsus tenuicrustatus in­ scarlet, and the underside bluish-white. One habits the Indo-Pacific region. from Chamela Bay was similar, except that Geograpsus lividus (Milne Edwards, 1837, there were also white spots on the chestnut p. 85) ; Rathbun, 1918, p. 232; Boone, 1927, carapace. In other localities, smaller males p. 253; Sivertsen, 1934, p. 19; Schmitt, had a chestnut tinge on the edges of the 1939, p. 25; Garth, 1946, p. 506. 19 speci­ sternum and posterior part of the carapace, mens preserved from Mexico (Tenacatita, or had the carapace completely dark but the Guatulco), Nicaragua (San Juan del Sur), chelae, legs and sternum brilliant red. Costa Rica (Port Parker, Culebra, Jasper I.), Only at Tangola-Tangola did the color Colombia (Gorgona I.). Many others seen adumbrate that of the Galapagos colony. but not saved. Eggs seen from Nov. to April Although the crabs showed the usual local (Mexico to Colombia). Under large loose coloring in general, having the carapaces stones on rock shores, or with substratum of black spotted with blue, and the legs black coral and sand; rarely in similar localities spotted with bluish-green, the carapace in near mangroves; lives well above low tide both sexes was frequently washed poste­ marks (Zone 2). riorly with chestnut. Of six females, 34 to Ground color of carapace varying from 60 mm. long and all ovigerous, three had a bright yellowish-green through pale emerald reddish tinge on the sternum only, while the to black; reticulations or marblings con­ chelae were deep wine-color. The smallest trasting, black or purple on light crabs, males showing any red were about 30 mm. green on black ones. Chelipeds sometimes long and had a chestnut tinge on the borders tinged with orange, or rusty orange above of the carapace and sternum, but not on the mottled with black; legs blue green to pur­ legs. plish; hairs yellow. Eggs purple. Young The agility of these crabs and their gre­ (7 mm. long), very pale green with black garious custom of sunning themselves in reticulations very narrow; chelipeds buff. groups on damp rocks are well known. When Have not seen on the west coast the colora­ forced into the water they are good swim­ tion recorded by Rathbun ("Yellowish red mers, but return to the rocks as soon as with reticulating lines or patches of a darker possible. They are distinctly diurnal; at red or purplish; sometimes wholly red."). night they lie quietly in cracks or on open This may be typical of the east coast mem­ rocks above the reach of the tide, and are ber of the species. so torpid that they often can be picked Of five stomachs containing food, one up without making any effort to escape, held remains of a .minute sea urchin, two, whether or not a flashlight is used. They insect remains (probably beetles), two am- feed by plucking the fur-like algae from phipods, and two, a few bits of gravel. the rocks, using the spooned chelipeds Range: Florida keys to Brazil; Bermu­ alternately. However, although predomi­ das; Lower California to Chile; Galapagos; nantly algae-eaters, there is no doubt but Hawaiian Islands. 1947] Crane: Brachygnathous Crabs from Tropical America 85

Gofifopsis pulchra (Lockington, 1877, p. with many tunnels parallel to the surface, 152) ; Rathbun, 1918, p. 239. 43 specimens although a few deep holes existed ; some in­ preserved from Mexico (Chamela), Nicara­ dividuals lived under old mangrove logs. gua (Corinto), Costa Rica (Culebra, Pun- When pursued, these crabs use any hole tarenas, Golfito), Panama (Honda), Colom­ at all to escape ; unlike Uca they apparently bia (Gorgona I.) and Ecuador (Puerto Boli­ have little sense of property. var). Eggs in Dec. (Nic), Feb. (C.R.). Range: From Magdalena Bay, Lower Among mangroves, especially along banks California, to Peru . of estuaries and lagoons, close to water line Pachygrapsus transversus (Gibbes, 1850, (Zone 6). Rarely in almost fresh water, with p. 181) ; Rathbun, 1918, p. 244; Boone, 1927, no mangroves within several hundred yards. p. 255, 1929, p. 577; Pesta, 1931, p. 179; General color dark above with light spots ; Finnegan, 1931, p. 649; Sivertsen, 1934, p. chelipeds and legs reddish; females duller. 19; Schmitt, 1939, p. 25; Garth, 1946, p. In more detail the coloration is as follows: 507. 121 preserved from Mexico (Sihuate- ground color of carapace usually jet black; nejo, Tangola-Tangola), El Salvador (G. of the round to elongate spots and bars are Fonseca), Nicaragua (Cardon I. at Corinto, pale olive brown to pale buff, fading to white near Potosi R. in Gulf of Fonseca, San Juan on sides and posterior margins of carapace. del Sur), Costa Rica (Port Parker, Culebra, These markings are very variable in size Uvita), Panama (Honda), Colombia (Gor­ and number, but a few large ones are al­ gona I.). Eggs are plentiful everywhere most always present on postero-lateral sides from Nov. to March. This species is the of carapace. Chelipeds bright rufous to bril­ most abundant and ubiquitous of shore liant scarlet in males, except for black tu­ crabs; it is found in all zones where there bercles and creamy dactyls and distal part are stones or rocks, from moderately brack­ of manus ; in females and young the merus ish water to open coasts, on muddy, sandy and carpus are usually blackish-red to or stony substrata, in tidepools, and even blackish-brown with other segments yel­ among mangrove roots or logs with stones lowish-cream washed with orange. Merus of among them (Zones 1, 2, 3, 4, 6, 7, 8). It ambulatories in males sometimes bright fails to occur only in coral, open mud or scarlet, sometimes only tinged with rose open sand, although it is rare on the most posteriorly; other segments pale olive brown exposed surf-beaten rocks where Grapsus to pumpkin orange, or light reddish, the and Eriphides are typically found. The lar­ manus spotted with black and white; all gest crabs are always found on the larger segments with black hairs and white spot rocks, small ones stay near pools or under at base of each hair. Underparts creamy small stones. Length of largest male 13.5 except external maxillipeds which are pure mm. ; largest ovigerous female 11.5; smallest white; legs of female without red, plain buff ovigerous female 6.5 mm. marked with black. Eggs dull purple. The There is considerable color variation, the red develops late; young crab (about 10 greenest crabs being among green weed, mm.) black with small cream spots all over and the darker ones on dark stones. Typi­ except for manus and chelae which have cally, the crab is very dark green or black black dorsal ridge, apricot buff central por­ with bright green marblings or striations; tion, and cream pollex and lower half of longitudinal bar of bright green on intes­ manus. A 12 mm. specimen was olive green tinal region, and a transverse line of this all over except for typical white spots on color in both proximal and distal joints of postero-lateral sides of carapace; under­ carpus; chelae and lower three-quarters of parts, manus, dactyls and chelae all cream. manus creamy; upper and lower sides of A single male at Gorgona was much redder ambulatories same as carapace and faintly than any others seen, the color continuing banded with cream. even on the carapace, rather as in the At­ The following notes made at Cardon I., lantic cruentata. Corinto, concern behavior which is typical The steep banks of estuaries and man­ of these crabs everywhere along their Paci­ grove swamps proper are often honey­ fic coast range. "Dec. 31. Low tide. 13 small combed with the burrows of this crab. Each Pachygrapsus seen in an area near low-tide burrow typically has two or more entrances, level measuring 1X3 feet, composed of often close together; they tend to run paral­ large and small stones exposed in a pool lel, close to the surface, for long distances, between boulders. All of the crabs, in both although holes more than three or four feet sun and shade, were out of water feeding deep usually go down to water level, then on algae as fast as they could, using their back up and in; often they lead into each chelae alternately in perfect rhythm. Their other or have common entrances. At Balle- bodies appeared very green and algae-like nas the holes were everywhere on a low in the sun, yet in the shade the darker black muddy flat that was always completely cov­ markings gave the tone, so that, like the ered at high water; very few mangroves algae in shadow, they appeared almost grew here; the ground was honeycombed, black. Twenty-five minutes after low tide 86 Zoological New York Zoological Society [32: 9 the water had risen a good three inches in and chelae entirely cream except maroon the pool, although it was still quiet. Never­ striations on upper margin. Underparts all theless, most of the best algae was now un­ cream washed with gray. Eggs chocolate der water, and not one of the 13 crabs was brown. in sight. Evidently, they prefer to feed in One specimen found in stomach of white the air, and since the richest algae beds are ibis, Corinto. uncovered in these near-low-tide zones for The females and young, neither in our such a very short time, the reason for their series nor in that at the United States Na­ haste in feeding is evident. During the en­ tional Museum, have the full number of tire morning I saw only one Pachygrapsus spinules on the dactyl. Typical counts of our feeding under water, and that was in a half­ specimens are as follows: female, 4.8 mm., hearted fashion for a few moments only. no side tooth, no dactyl spinules, legs slight­ "The original 13 had no territorial pre­ ly more slender than in adult (this specimen cincts, individuals sometimes feeding alone was taken at Ballenas in midst of a colony on a rock, sometimes within three inches of this species, so there is no reasonable of a neighbor, and moving on to a new spot doubt of the identification) ; male, 5.1 mm., two or three inches away after a minute or has side tooth, beginning of spinules, thicker so. Could see a movement of mine a good legs; ovigerous female, 14 mm., 9 dactyl foot or more away, and would stop eating spinules; male, 17 mm., 9 dactyl spinules; at once and run into a crevice. A half- male, 20 mm., 10 dactyl spinules. A con­ grown Grapsus startled a Pachygrapsus spicuous short longitudinal ridge, not men­ away from its algae ; it ran four inches and tioned in the descriptions, runs along mid­ started feeding again under a ledge, while dle of outer surface of palm in male; this the Grapsus took up grazing in the Pachy­ ridge is present also in U.S.N.M. specimens. grapsus' first site. Another Pachygrapsus Range: From La Paz, Lower California, backed into a grazing snail, the snail struck to Panama. out viciously with its foot, and the Pachy­ Sesarma rhizophorae Rathbun, 1906, p. grapsus ran away in this case too, although 99; 1918, p. 294. 2 specimens, male 8.3 mm., it was fully as large as the snail. ovigerous female, 8.4 mm., from Costa Rica "The larger Pachygrapsus dare to get (Puntarenas and Ballenas). Among man­ farther from the pools, grazing on top of groves (Zone 6). Compared with holotype the large boulders in damp hollows. They and other specimens in U. S. National Mu­ are startled by a human movement as much seum. Agrees perfectly except that the gran­ as two feet away. ules are more strongly developed in the holo­ "These crabs are active and feed at night, type than in our specimen. but not as much as during the day. They Range: Known only from Costa Rica. appear brown at night, like the weed and Aratus pisonii (Milne Edwards; 1837, p. rocks, in the light of an electric torch." 185) ; Rathbun, 1918, p. 323. Boone, 1930, Among their enemies are carnivorous p. 207; Finnegan, 1931, p. 651. 16 specimens tidepool fish; we took them from the stom­ preserved from Nicaragua (Corinto, San ach of a blenny, Malacosteus xonifer, and Juan del Sur), Costa Rica (Port Parker, of the common tidepool goby, Bathygobius Ballenas, Golfito), Panama (Honda). On soporator. west coast of America, always on mangrove Range : Cosmopolitan in the tropics. boughs, well above water (Zone 6). Sesarma sulcatum Smith, 1870, p. 156; Typical coloring: entire gastric portion Rathbun, 1918, p. 289. 10 specimens from of carapace nopal red (Ridgway) ; surround­ Costa Rica (Negritos, Ballenas, Golfito). In ing parts, including front and anterolateral gravelly mud along a lagoon shore, on banks margins, off-white marbled with dark brown. of drying streams (nearly or completely Chelipeds nopal red. Inner parts and tips of freshwater), and in slightly brackish man­ dactyls flame scarlet. Hairs black with straw grove mud (Zones 6, 7). tips. Eyes olive gray. Eye stalks nopal red Large male from Golfito: Carapace and with black dots. Ambulatories dark gray legs plain dark brownish-gray; cheliped marbled with black and, on merus, washed merus, carpus, upper half of manus and with orange-brown. Sternum and abdomen upper basal part of movable finger chocolate white. Underside of ambulatories pearl brown; lower half of manus and rest of gray. chelae bright creamy yellow; sternum, ab­ Range: Coasts of America, from Florida domen and all except manus and dactyls of to Brazil and from Nicaragua to Peru. undersides of ambulatories light buff; un­ dersides of manus and dactyls grayish- HABITAT ZONES. brown. Ovigerous female: with yellow line The habitats of the intertidal brachyuran across front, rest yellow brown all over crabs (as limited on p. 69) taken by the mottled with black except chelipeds which Eastern Pacific Expedition proved to divide are as follows: merus and carpus cream themselves into nine quite distinct zones. with striations and tubercles maroon. Manus These may be listed as follows: 1947] Crane: Brachygnathous Crabs from Tropical America 87

1. Surf Rocks. The following lists represent the sum­ 2. Stones near Mid-tide Levels: that is, marized results of daily collections and tidal stones well above low tide levels. notes made on 79 different species from 3. Stones near Low-tide Levels: tidal more than 50 geographic localities. More stones only briefly uncovered by the tide. than 3,500 specimens were collected and, 4. Tidepools. of the more common forms easily identified 5. Coral: Pocillopora. at sight—for example, Grapsus, Goniopsis 6. Mangroves : swamps and estuary and Ocypode—literally thousands of addi­ banks. tional individuals were seen and their habi­ 7. Mudflats: open, unshaded. tats noted, although no specimens were 8. Sheltered Beaches: sandy-mud or collected. sandy. The zone references in parentheses follow­ 9. Exposed Beaches : sandy. ing species names refer to the other zones It will be noted that in Zones 1-5, the in which that form was taken, and are given substratum is hard, while in 6-9 it is more for purposes of easy cross-reference. or less soft. In 1-5 and in 9, the salt con­ In the concluding section is given a sum­ centration of the water is high, approaching mary of the relative richness of habitat that of open ocean; in 6, 7 and 8 it is low, zones. ranging from almost fresh to around 75% Zone 1. Surf Rocks. This habitat consists of oceanic salinity. Unfortunately, no exact of exposed rocks and cliffs to which algae salinity analyses were made of these various are usually attached. Technically, it should habitats, except in the case of a few species be divided into two parts, an upper region of Uca. Obviously, the nine zones could be dampened only by spray or exceptional tides, divided into a number of smaller niches, but and a lower zone which is covered twice this subdivision must await future, more daily by normal tides. Since the scanty exact investigation in the field. brachyuran fauna is little affected by these These nine habitats will be described be­ distinctions, they are not observed in this low in more detail, and a list of the crabs list. The four species found in the zone are occurring in each will be given. It must be the following:— emphasized that these are only the records Majidae : made by the present author. Some of the Acanthonyx petiverii. Also in tidepools (4). observations, such as the occurrence of Grapsus in the surf zone, have been re­ Xanthidae : peatedly recorded by previous writers: Eriphides hispida. others, such as the restriction of certain Grapsidae : species to Pocillopora coral, although well Grapsus grapsus. known to even amateur field naturalists, Pachygrapsus transversus. Rare here; also appear never to have been published in the present in all other zones except coral (5) reports of this area. Although years of field and exposed beaches (9). . work would be needed to make a complete Zone 2. Stones Near Mid-tide Lev els. This report on this subject, still the usual habi­ zone is represented by tidal stones between tats of the more common species are without mean and high-tide marks. It is distin­ question tkose given. The écologie ranges guished from the next chiefly by the scar­ of the rarer forms will, however, unques­ city or absence of algae, serpulids, corals tionably be extended to other habitats. The and other growths upon the under sides of following species included in the present the stones. This habitat occurs frequently report were also taken on the Zaca in deeper between the ends of protected beaches and water: Teleophrys cristulipes, Mithrax the boulders or cliffs which form the adja­ wygmaeus, M. areolatus, Anaptychus COMÊH- cent promontory. tus and Xanthodius stimpsoni. A few otner species, such as Daldorfia .garthi, which Xanthidae : were taken only on shore or in Pocillopora Leptodius taboganus. on the Zaca, have been reported by the Xanthodius sternberghii. Also under stones Hancock and other expeditions from deeper near low tide (3) and in tidepools (4). water as well. Eurypanopeus planus. In spite of the above limitations, one of Menippe frontalis. the clearest results of the present study is Eriphia squamata. Also in tidepools (4) the restriction of the vast majority of spe­ and, rarely, among mangroves (6). cies to only two or three niches having a Grapsidae: number of characters in common—for ex­ Geograpsus lividus. ample, tidepools, stones near the low-tide Pachy grapsus transversus. Also present in level, and Pocillopora coral, or mangroves all other zones except in coral (5) and on and open mudflats. Finally, a considerable exposed beaches (9). number appear to be confined to a single Ocypodidae : zone. Uca panamensis. 88 Zoologica: New York Zoological Society [32:9

Zone 3. Stones Near Low-tide Levels. This kinds of algae. It is usually in the algae that zone is represented by tidal stones near low- most of the following crabs are found. tide marks. They are uncovered at most only Majidae: an hour or so during each tidal period, and Eucinetops panamensis. Also under stones during neap tides may be underwater for near low-tide levels (3). days at a time. Therefore, since the under­ Acanthonyx petiverii. Also on surf rocks sides of the stones never dry out, they are encrusted with a varied sessile fauna and (1). flora, consisting chiefly of algae, sponges, Pelia pacifica. Also under stones near low- corals, bryozoans, serpulid worms and tuni- tide levels (3) and in coral (5). cates. Here gather also many non-sessile Thoe sulcata. Also under stones near low- animals, such as starfish, serpent stars, tide levels (3) and in coral (5). holothurians, worms, mollusks and snap­ Anaptychus cornutus. Also under stones ping shrimps. As is to be expected, the crab near low-tide levels (3) and in coral (5). fauna is rich, particularly in spiders. Most Mithrax denticulatus. Also under stones of the species cling upside down to the near low-tide levels (3) and in coral (5). growth on the stones. Mithrax orcutti. Majidae: Teleophrys cristulipes. Rare here; typically present in coral (5). Eucinetops panamensis. Rare here ; typically Microphrys platysoma. Also under stones present in tidepools (4). near low-tide levels (3) and in coral (5). Pelia pacifica. Also in tidepools (4) and Xanthidae : coral (5). Actaea dovii. Also in coral (5). Herbstia tumida. Also in coral (5). Actaea sulcata. Rare here; typically present Thoe sulcata. Rare here; typically present in tidepools (4) and coral (5). in coral (5). Pitho sexdentata. Xanthodius sternberghii. Also under stones near mid-tide (2) and low-tide (3) levels. Anaptychus cornutus. Also in tidepools (4) Xanthodius stimpsoni. Also under stones and coral (5). near low-tide levels (3) and in coral (5). Mithrax denticulatus. Rare here; typically Lophoxanthus lamellipes. Also under stones present in tidepools (4) and coral (5). near low-tide levels (3) and in coral (5). Teleophrys cristulipes. Rare here; typically Metapocarcinus concavatus. present in tidepools (4) and coral (5). Menippe obtusa. Parthenopidae : Pilumnus gonzalensis. Daldorfia garthi. Usually found in deeper Pilumnus pygmaeus. Also under stones near water. low-tide levels (3). Xanthidae : Ozius agassizii. Also under stones near low- Daira americana. Rare here ; typically pres­ tide levels (3). ent in coral (5). Ozius verreauxi. Rare here; typically pres­ Cyclothanops vittatus. Also in coral (5). ent under stones near low-tide levels (3). Leptodius taboganus. Also under stones Eriphia squamata. Also under stones near near mid-tide levels (2). low-tide levels (2) and, rarely, among Xanthodius sternberghii. Also under stones mangroves (6). near mid-tide levels (2) and in tidepools Grapsidae : (4). Pachygrapsus transversus. Also present in Xanthodius stimpsoni. Also in tidepools (4) all other zones except in coral (5) and and coral (5). on exposed beaches (9). Lophoxanthus lamellipes. Also in tidepools Zone 5. Coral (Pocillopora). This distinc­ (4) and coral (5). tive habitat zone is included in the present paper on intertidal crabs for two reasons. Xanthidae : First, although the coral usually lies at least Pilumnus pygmaeus. Also in tidepools (4). three feet and usually from six to eighteen Ozius verreauxii. Also in tidepools (4). or more feet under water, it is occasionally Ozius perlatus. partially exposed during spring tides. Sec­ Ozius agassizii. Also in tidepools (4). ond, its fauna overlaps that of the tidal Grapsidae : zones, rather than that of the deeper littoral. Pachygrapsus transversus. Also present in Associated with the very characteristic bra- all other zones except in coral (5) and on chyuran fauna, are equally well-marked ani­ exposed beaches (9). mals of other groups, particularly the snap­ Zone 4. Tidepools. This habitat is too well ping shrimp, Crangon ventrosus, as well as known to need discussion, except to point numerous other shrimps, serpent stars, out that tidepools are usually in an exposed worms, and occasional mollusks and fish. position, and that their rocky, uneven sides More than fifty heads of coral, ranging in and bottoms give excellent support for many diameter from six inches to more than two 1947] Crane: Brachygnathous Crabs from Tropical America 89 feet, were carefully hammered open and their Eurytium tristani. Also on mudflats (7). inhabitants collected. Of the 21 species of Grapsidae : brachygnathous crabs found, nine were nev­ Eriphia squamata. Rare here; present er taken by us in any other habitat. among stones near mid-tide levels (2) Majidae: and in tidepools. Pelia pacifica. Also under stones near low- Goniopsis pulchra. tide levels (3) and in tidepools (4). Pachygrapsus transversus. On roots and Herbstia tumida. Also under stones near stones only. Also present in all other zones low-tide levels (3). except in coral (5) and on exposed beaches Thoe sulcata. Also under stones near low- (9). tide levels (3) and in tidepools (4). Sesarma rhizophorae. Anaptychus cornutus. Also under stones Sesarma sulcatum. Also on mudflats (7). near low-tide levels (3) and in tidepools Aratus pisonii. Among mangrove branches (4). only. Mithrax denticulatus. Also in tidepools (4) ; Ocypodidae: rare under stones near low-tide levels (3). Uca zacae. Mithrax pygmaeus. Uca schmitti. Teleophrys cristulipes. Also, rarely, under Uca brevifrons. stones near low-tide levels (3) and in tide- Uca tomentosa. pools (4). Uca umbratila. Microphrys platysoma. Also under stones Uca inaequalis. Also on mudflats (7). near low-tide levels (3) and in tidepools Uca tenuipedis. (4). Uca batuenta. Xanthidae : Uca crenulata. Carpilodes cinctimanus. Uca argillicola (in clayey mud) ; (type se­ Actaea dovii. Also in tidepools (4). ries only). Actaea sulcata. Also, rarely, in tidepools (4). Uca limicola (type series only). Daira americana. Also, rarely, under stones Uca latimanus. Rare here; typically on shel­ near low-tide levels (3). tered beaches (8). Medaeus spinulifer. Zone 7. Open Mudflats. In this and the Cyclothanops vittatus. Also under stones following zone (8), there is a complete lack near low-tide levels (3), of shade, but mangroves are almost always Xanthodius stimpsoni. Also under stones at least within sight of the human eye. The near low-tide levels (3) and in tidepools richest areas are close to the vegetation ; the (4). center of the flats are usually lacking in Lophoxanthus lamellipes. Also under stones crabs. As in the preceding zone, some of the near low-tide levels (3) and in tidepools species below are found only or chiefly where (4). some stones are present in the mud. Micropanope xantusii. Xanthidae : Pilumnus xantusii. Panopeus purpureus. Also among mangroves Heteractaea lunata. (6). Domecia hispida. Panopeus chilensis. Trapezia cymodoce ferruginea. Eurypanopeus transversus. Among stones Trapezia digitalis. only. Also among mangroves (6) and on Zone 6. Mangroves. This zone includes sheltered beaches (8). both swamps, estuaries, and the edges of Eurytium tristani. Also among mangroves lagoons — wherever mangroves are found. (6). Fiddler crabs (Uca) are the most typical Grapsidae : and abundant crabs of these brackish areas, Pachygrapsus transversus. Among stones the characteristics of which are too well only. Also present in all other zones ex­ known to require further comment. It should cept in coral (5) and on exposed beaches only be noted that small stones are often (9). present near the edge of a swamp and that Sesarma sulcatum. In gravelly mud only. some species, particularly Eurypanopeus Also among mangroves (6). transversus, do not occur where stones are Ocypodidae: absent. Below are included only those spe­ Uca princeps. Also on sheltered beaches (8). cies found among the mangrove roots or in Uca heteropleura. Also on sheltered beaches their shade. Those living on nearby mud­ flats are in subsequent categories (7 and 8). (8). Uca stylifera. Also on sheltered beaches Xanthidae : (8). Panopeus purpureus. Also on mudflats (7). Uca insignis. Also on sheltered beaches (8). Eurypanopeus transversus. Among stones Uca macrodactyla. only. Also among stones on mudflats (7) Uca schmitti. and sheltered stony-mud beaches (8). Uca galapagensis. 90 Zoologica: New York Zoological Society [32: 9

Uca oerstedi. to encourage an especially rich and varied Uca inaequalis. Also among mangroves (6). littoral brachyuran fauna. Uca saltitanta. Thanks to the tireless work of Mary J. Uca beebei. Also on sheltered beaches (8). Rathbun, and, more recently, of Susan Zone 8. Sheltered Beaches. These include Finnegan, Steve Glassell and John S. Garth, stretches of sandy-mud or sandy shores, un­ the taxonomy and geographical distribution shaded, covered at high tide by brackish of the shore crabs of the tropical eastern water. Open water, whether estuary or nar­ Pacific are becoming very well organized row-mouthed bay, is usually closer than in and understood. These questions will not be Zone 7. considered here, except to remark on the convenience, for field workers, of the rela­ Xanthidae : tively wide ranges of most of the common Eurypanopeus transversus. Only among oc­ shore species, which often extend from Cape casional stones. Also among mangroves San Lucas to Panama and beyond, as well (6) and on mudflats (7). as the occurrence of a number of species Grapsidae : which are cosmopolitan in the tropics. Pachygrapsus transversus. Only among oc­ 1. RICHEST COLLECTING STATIONS: Our casional stones. Also present in all other experience on the Zaca showed a number of zones except in coral (5) and on exposed localities where crab collecting was espe­ beaches (9). cially fruitful, and a number of others Ocypodidae : where shore life in general and the crab Ocypode gaudichaudii. fauna in particular were so poor that the Ocypode occidentalis. Rare here; typically results were scarcely worth the effort of on exposed beaches (9). landing. For the benefit of future workers, Uca princeps. Also on mudflats (7). these richer bays are listed here. It should Uca heteropleura. Also on mudflats (7). be kept in mind, however, that local shifts Uca stylifera. Also on mudflats (7). in population, the laying of pipe lines, or Uca insignis. Also on mudflats (7). natural or artificial swamp drainage may Uca festae. swiftly ruin the best of collecting grounds. Uca beebei. Also on mudflats (7). On the other hand, the richest colonies are Uca stenodactyla. often found near sewer outlets and garbage dumps, provided the water is not polluted Uca deichmanni. by oil or chemicals. Examples of such rich­ Uca latimanus. ness, which are due at least partly to nearby Uca terpsichores. habitation, are the entrance to Corinto har­ Zone 9. Exposed Beaches. This zone is bor and certain localities around the mouth always sandy, and the concentration of the of the Panama Canal. water approaches that of normal open ocean. During the Eastern Pacific Zaca Expedi­ Ocypodidae: tion of 1937-1938, and my later (1941 and Ocypode occidentalis. Also on sheltered 1944) trips to Panama and Ecuador, the beaches (8). most fruitful localities, from the point of view of inter-tidal crab populations, were CONCLUDING REMARKS ON FIELD the following (see map, p. 70) : OBSERVATIONS. A paper such as this one, which is com­ Mexico : posed largely of field notes, can never be Acapulco. Moderately good; chiefly rocky prepared without a feeling of deep dissatis­ short habitats and coral. faction. The individual observations are so Tangola-Tangola. Of the three adjacent fragmentary, the basic problems involved so bays, Guatulco, Santa Cruz and Tangola- little understood, that the only excuse for Tangola, the latter was by far the best. putting the notes on record lies in the scar­ Stony, rocky and sandy beach and tidepool city of field observations of any kind. With habitats; Pocillopora; the extensive lagoons, these facts in mind, it seems worthwhile to with mangroves, were not investigated for conclude with a few remarks on the ecology, crabs. coloration and behavior of these crabs, Nicaragua : which may suggest lines for worthwhile Corinto. Excellent. Many habitats, from future study. Planned research in any of marine stones, rocks and tidepools at Car- these directions would add not merely to don Island, to brackish water mudflats and knowledge of the Brachyura, but also to the mangroves. clarification of vital problems of theoretical Costa Rica: biology. All such studies on these north- Port Parker. Excellent. Many habitats tropical Eastern Pacific shores are facili­ accessible, from coral and marine rocks, tated by the characteristic warm waters, stones and tidepoofs at Abajos Point to relatively well-watered shores, high tides fresh-water streams. Limited mangrove and and adequate bays and gulfs, which unite mud-flat areas. 1947] Crane: Brachygnathous Crabs from Tropical America 91 Culebra. Mediocre stony shore popula­ intact; third, extensive representations of tions, but good Pocillopora easily available; some of the best known species, such as the latter were in individual heads rather Grapsus and Goniopsis, were not considered than in reef form. necessary. Piedra Blanca. Good rock, stone, beach Field notes made on the Zaca from Aca- and tidepool habitats. pulco to Panama, however, leave no doubt Gulf of Nicoya. The upper portion, around as to which were the most abundant species Puntarenas, was excellent for brackish wa­ among these intertidal crabs. Naturally, it ter, mangrove and mud-living species. Natu­ is impracticable to compare numbers of a rally, no coral was found here, but excellent large form such as Grapsus with a small one Pocillopora, in extensive reef'formation, oc­ such as Pachygrapsus, or the dominant form curred toward the mouth of the Gulf around in one habitat zone with that in another, Jasper Island. Ballenas Bay, beside the but irrespective of zones, the following spe­ mouth, had a good lagoon fauna (mangrove cies are certainly among the most widely and mudflat), but the stony shore and tide- distributed and generally accessible, ob­ pool collecting was poor. servable, abundant and successful of all the Uvita Bay. Moderately good exposed crabs within the area under discussion; stony reef, rock and beach collecting; Po­ they are arranged in taxonomic order : cillopora present; also a good fresh-water Xanthodius sternberghii (Zones 2, 3, 4). » stream. Eurypanopeus planus (Zone 2). Golfito, in Gulf of Dulce. This practically Eriphia squamata (Zones 2, 3, 4). uninhabited locality was wonderfully rich Trapezia cymodoce ferruginea (Zone 5). in all mud- and sandy-mud-living forms, Grapsus grapsus (Zone 1). having extensive protected mudflats and Geograpsus lividus (Zone 2). mangroves, and fresh-water rain-forest Pachy grapsus transversus (Practically streams. We have heard, however, that it ubiquitous, except in coral and on open has been spoiled, zoologically speaking, by sandy beaches). one of the fruit companies. Ocypode occidentalis (Zone 9). Panama and the Canal Zone: Ocypode gaudichaudii (Zone 8). Bahia Honda. Good, semi-exposed stony Of course, many other species, e.g. a num­ shore and beach collecting; also fair Po­ ber of Uca, are locally abundant. cillopora, mudflats and brackish streams. A thorough study of any one of these Panama City and Balboa. The beach at readily available species would be certain to Bellavista and the mangrove pocket known yield excellent results. as La Boca still had adequate brackish- Spider crabs are notable for the absence water crab populations as late as 1944. They of numerically abundant species. had deteriorated, however, since 1941, be­ 3. HABITATS. Conditions naturally vary cause of wartime construction at La Boca locally, but the following species are most and some apparently natural silting up of universally present in their respective zones. mudflats at Bellavista (cf. Crane, 1941). Zone 1. Surf Rocks. Grapsus grapsus. Colombia : Zone 2. Stones near mid-tide levels. Xan­ Gorgona Island. (The only locality visited thodius sternberghii, Eriphia in Colombia). Moderately good shore-crab squamata. Uca panamensis and populations. Eurypanopeus planus are prac­ Ecuador : tically always present in the Puerto Bolivar (at mouth of Guayas mixed sand and stony area at ends River). Excellent sheltered beach, mudflat of protected beaches. and mangrove crab fauna here and on near­ Zone 3. Stones near low tide levels. No by Jambeli Island. The swamps were being species outstanding, since local drained in 1944, but the crab colonies, par­ conditions vary greatly. ticularly of Uca, are so extensive that they Zone 4. Tidepools. Same remarks as for should be safe for some years. Zone 3. Guayaquil. The few, nearly fresh-water Zone 5. Coral {Pocillopora). Trapezia cy­ forms which can live here were all thriving modoce ferruginea. in 1944. The apparently endemic Uca festae Zone 6. Mangroves. Goniopsis pulchra; is abundant. Aratus pisonii. 2. ABUNDANCE. The numbers of individu­ Zone 7. Open mudflats. No species out­ als of the various species in the expeditions' standing. collection give no clue to their actual abun­ Zone 8. Sheltered beaches. Ocypode gau­ dance in the field for three reasons : first, no dichaudii. effort was made to make collections from this point of view ; second, some of the more Zone 9. Exposed beaches. Ocypode occi­ common forms, such as Eriphides of the dentalis. surf zone, were difficult to reach and collect In regard to the richness of habitat zones 92 Zoological Neiv York Zoological Society [32: 9 in number of species in the collections, tide- graphical and/or ecological, and further ob­ pools and Pocillopora coral lead with 22 spe­ servations are greatly needed. One example cies each, followed by mangroves with 21, is discussed under Grapsus (p. 84), and low-tide levels with 20, mudflats with 17 and others in the discussions of Uca princeps protected beaches with 14. The poorest are and U. beebei (Crane, 1944, p. 166). Some­ exposed beaches with 1 species (0. occi­ times geographic variation in color is indi­ dentalis), surf rocks with 4 and stones at cated in the rare observations of young mid-tide levels with 8. stages from different localities. For ex­ A field in which excellent detailed work ample, the juvenile color patterns of Carpi- could be done on this coast concerns the lodes cinctimanus, Actaea dovii, Actaea sul­ structural and physiological adaptations to cata, Cycloxanthops vittatus and Ozius per- niches. For example, the high proportion of latus appear to differ on the mainland and hairy or decorated species which cling to in the Galapagos, (cf. color descriptions of the encrusted stones of low tide regions is these species in the present paper with those always striking when contrasted with the of Garth, 1946.1). predominantly naked or scarcely pilous forms The field of epigamic colors is practically of the mudflats. Subdivisions of this sub­ unexplored in crabs, except for some obser­ ject, concerning the variations in attach­ vations on Uca. Especially needed are in­ ment, amount and kind of decoration in genious, basic experiments on color vision, spider crabs are most interesting; a few and on the tendency of certain crabs in examples have been given in the systematic breeding condition to develop white pigment part of this paper. (see Crane, 1944). Again, the variations in foot structure, 5. DAILY ACTIVITY CYCLE: This field was for clinging versus digging functions, for scarcely touched during the expeditions, example, show beautiful adaptations. Fi­ since opportunities for night observation nally, although work has been done on were few. The following divisions, however, desiccation tolerance among east coast shore were well established. crabs (i.e. Pearse, 1936), west coast forms, Diurnal: Grapsus grapsus; Ocypode gau­ which are subjected to exceptionally high dichaudii; most species of Uca2. and low tides, have not been investigated. Probably diurnal: Xanthodius stem­ Extreme adaptiveness to alternate and ir­ berghii. regular submergence and aestivation must Diurnal and noctural: Eriphia squamata have been developed, furnishing challeng­ (more active at night) ; Menippe obtusa; ing material for research. In Uca this toler­ Pachygrapsus transversus (more active ance is particularly striking. during daylight). 4. COLOR. The wide prevalence of pro­ Nocturnal: Geograpsus lividus; Ocypode tective coloration was, as usual, the most occidentalis. striking crab color characteristic on the 6. FOOD: The Zaca observations on feed­ Pacific expeditions. During the exceptional ing and stomach contents may be summar­ opportunities presented by the Zaca trips, ized as follows : the adaptive variability in accordance with Vegetarians: Daira americana; Xantho­ the terrain could be well appreciated. This dius stemberghii; Pachygrapsus transver­ was demonstrated both by different popula­ sus. tions of the same species, and by individuals Predominantly vegetarians : Grapsus within populations. The variability was grapsus. most notable in fairly active crabs on stony, Carnivores and scavengers: Menippe ob­ sandy, or sandy-mud beaches, that is, in tusa; Domecia hispida; Trapezia cymodoce forms to which protectively colored cara­ ferruginea; Trapezia digitalis; Geograpsus paces are presumably of vital importance. lividus; Ocypode occidentalis. Certain species, for example Xanthodius Omnivores : Eriphia squamata; Eriphides stemberghii, X. stimpsoni and Ocypode hispida; Eurypanopeus planus. gaudichaudii, all showed remarkable indi­ vidual and/or group adaptations to lighter Feeders on microorganizms and organic or darker substrata, whether the general detritus sifted from sand and mud : Goniop- color of a beach was involved, or only that sis pulchra; Ocypode gaudichaudii; Uca spp. of a group of atypically colored pebbles. (the latter are sometimes also scavengers). Whether these differences are genetic or In regard to the general feeding habits somatic, individually fixed or adaptive, is of these intertidal species, the rather ob­ unknown. Unfortunately, genetic study is vious statement may be made that all spider not yet practicable, because of lack of suc­ crabs and most_ xanthids, including natu­ cessful rearing technique. However, even rally all Pocillopora inhabitants, feed when the simplest experiments concerning the ex­ underwater, while the grapsids and ocypo- tent of individual ability to change color - Martin D. Burkenroad in a forthcoming paper reports would be very worthwhile. on the nocturnal, as well as diurnal, activity of an east coast Uca ; all members of the genus must now be rechecked Other forms of color variation are geo­ with his most interesting observations in mind. 1947] Crane: Brachygnathous Crabs from Tropical America 93 dids are typically feeders in the air. How­ 8. BREEDING SEASONS. The breeding rec­ ever, observation will certainly draw finer ords included in this paper show only the distinctions. For example, although Pachy- months during which eggs were found on grapsus transversus, which frequently specimens collected in the various countries. crawls around in tidepools, follows the grap- The sole conclusion that can be drawn at sid custom and seems never to feed under present is that the series of most species water, Sesarma and other mud-livers in the yielded ovigerous females between Decem­ family often eat when actually submerged ber and May, the months during which our in tidal puddles; this is also true occa­ collections were made. The actual length sionally of Uca. Again, Eriphia squamata and extent of the breeding seasons for dif­ feeds with apparently equal frequency both ferent species in single localities, their above and beneath the surface, being in this variation with latitude, and their relation to respect perfectly amphibious. the rainy season remain unknown. In the few observations that have been made, all species with spooned chelae are REFERENCES CITED. predominantly eaters either of close-grow­ ing rock algae, or of organic detritus in BEEBE, W. sand and mud. The species so far observed 1924. Galapagos: World's End. G. P. Put­ feeding in these fashions are Xanthodius nam's Sons. sternberghii, Pachygrapsus transversus, 1938. Eastern Pacific Expeditions of the New Grapsus grapsus, Ocypode gaudichaudii, York Zoological Society, XIV. Intro­ and the various species of Uca. The useful­ duction, itinerary, list of stations, nets and dredges of the Eastern Pacific ness of the spoon adaptation is obvious. An Zaca Expedition, 1937-1938. Zoologica, exception is Eriphides hispida, which is vol. 23, no. 14. probably chiefly carnivorous, although the minor chela is strongly spooned. 1942. Book of Bays. Harcourt Brace & Co. 7. SOCIAL BEHAVIOR. The fields of gre- BELL, T. gariousness, territoriality, aggression and 1835. Some Accounts of the Crustacea of the display are virtually untouched in these Coasts of South America, with De­ Pacific crabs, save for a beginning in Uca scriptions of new Genera and Species, founded principally on the collections (Crane, 1941), and few observations have obtained by Mr. Cuming and Mr. been made anywhere in the world. The fol­ Miller. Proc. Zool. Soc. London, vol. 3, lowing disconnected notes indicate the pos­ pp. 169-173. sibilities of crab-study as a focus for work on these general problems. BOONE, L. It was noted on the Zaca that, as in other 1927. The Littoral Crustacean Fauna of the animal groups, those crabs which are pre­ Galapagos Islands, Part I: Brachyura. dominantly vegetarian or feeders on micro- Zoologica, vol. 8, no. 4, pp. 127-288. organic food live in larger groups than pre­ 1929. A collection of Brachyuran Crustacea from the Bay of Panama and the fresh dacious forms: for example, Grapsus grap­ waters of the Canal Zone. Bull. Amer. sus, Pachygrapsus tranversus, Goniopsis Mus. Nat. Hist., vol. 58, no. 11, pp. pulchra, both species of Ocypode and most 561-583. Uca contrast with the solitary, carnivorous 1930. Scientific results of the cruises of the Menippe obtusa and, probably, Eriphides yachts "Eagle" and "Ara," 1921-1928, hispida. William K. Vanderbilt, Commanding. Unlike Uca, Goniopsis shows little sense Crustacea: Stomatopoda and Brach­ of territoriality, although both live com­ yura. Bull. Vanderbilt Marine Mus., parable lives. vol. 2, pp. 5-228. Sexual differences in aggression were CRANE, J. noticed particularly in Xanthodius stern­ 1937.1 The Templeton Crocker Expedition. berghii and Eurypanopeus planus, as well III. Brachygnathous Crabs from the as in Uca. In these forms, disturbed males Gulf of California and the West Coast are more aggressive than females, adopting of Lower California. Zoologica, vol. 22, the threat posture with chelipeds extended. no. 3, pp. 47-78. In Eriphia squamata, on the other hand, 1937.2 The Templeton Crocker Expedition. VI. both males and females threaten when ac­ Oxystomatous Crabs from the Gulf of tively disturbed, although the preferred re­ California and the West Coast of action is to retreat, and their young never Lower California. Zoologica, vol. 22, threaten. no. 7, pp. 97-107. 1940. Eastern Pacific Expeditions of the There is evidence that in Eurypanopeus New York Zoological Society, XVIII. planus and Trapezia cymodoce ferruginea On the Post-Embryonic Development the sexes remain paired while the eggs are of the Brachyuran Crabs of the Genus being carried, or, possibly, new pairs are Ocypode. Zoologica, vol. 25, no. 6, pp. being formed at that time. 65-82. 94 Zoological New York Zoological Society [32: 9

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