Eriphia squamata Stimpson, 1859

Koh, S. K. & Ng, Peter K. L., 2008, A Revision Of The Shore Crabs Of The Genus Eriphia (Crustacea: Brachyura: Eriphiidae), Raffles Bulletin of Zoology 56 (2), pp. 327-355 : 332-334

Eriphia squamata Stimpson, 1859

( Figs. 4, 7A–C )

Eriphia squamata Stimpson, 1859: 56 ; Stimspon, 1860: 217; A. Milne-Edwards, 1880: 339, Pl. 56 Fig. 3 ; Miers, 1886: 162; Rathbun, 1898b: 590; Rathbun, 1910b: 544, 586, Pl. 41 Fig. 1 ; Rathbun, 1923: 625; Rathbun, 1924b: 376; Rathbun, 1930: 550, Text–Fig. 84, Pl. 223, Pl. 224 Fig. 1 ; Boone, 1929: 575, Fig. 12 a–b ; Hult, 1938: 13; Garth, 1946: 482, Pl. 83 Figs. 5–6 . Crane, 1947: 81; Garth, 1948: 50; Buitendijk, 1950: 278; Holthuis, 1954: 33; Garth, 1957: 66; von Prahl, 1982: 80, Fig. 9 a–b ; von Prahl & Froidefond, 1985: 268; Lemaitre & León, 1992: 56; Hendrickx, 1995: 95; Hendrickx, 1996: 615; Boschi, 2000: 80; Ng et al., 2008: 63.

Eriphia laevimana var. smithii – Cano, 1889: 102, 210 (part). (not MacLeay, 1838)

Material examined. – CENTRAL AMERICA: 2 males (23.2 × 33.5 mm, 14.7 × 21.3 mm), 3 females (21.6–19.1 × 31.3– 27.8 mm), 2 juveniles (12.1 × 19.0 mm, 10.3 × 14.8 mm) ( NHM uncat.), west coast Central America , coll. Captain Daw; 2 dried males, 1 dried female ( MMUS – C 2117–2119 ), California. PANAMA : 1 male (29.9 × 40.9 mm), 1 female (27.5 × 39.5 mm) ( USNM 17787 ). MEXICO : 1 male (15.5 × 22.5 mm), 1 female (12.0 × 19.5 mm) ( USNM 50481 ), Agua Verde Bay , coll. Albatross Expedition, 21 Apr.1911 .

Type locality. – Mazaltan , Mexico .

Diagnosis. – Carapace transversely hexagonal, dorsal surface relatively flat, tuberculated, tubercles may be arranged in twos or threes, slightly pubescent anteriorly. Hepatic region separated by transverse groove extending from second anterolateral spine. Front with two transverse ridges immediately behind frontal margin, denticulated to varying degrees. Orbit oval, deep, entire margin denticulated; external and internal orbital spines present; supraorbital and infraorbital margins each with two longitudinal fissures. Anterolateral margin convex, with six or seven acute spines. Surface of third maxilliped minutely granulated, sparsely pubescent. Pterygostomial region pubescent, minutely granulated. Suborbital region slightly denticulated. Cheliped surface tuberculated; denticles present at ventral margin of basis-ischium and merus; anterior margin of merus pubescent, surface relatively smooth; carpus covered with large, flattened tubercles distally, with prominent acute spine on distal inner margin and a smaller one below ventral surface; outer surface of chela covered with flattened tubercles arranged in longitudinal rows, rounded tubercles may be present on dactylus; tubercle rows on larger chela always prominent, dense. Surface of ambulatory leg smooth, both anterior and posterior margins pubescent. Anterior male thoracic sternum smooth anteriorly. G1 relatively short, stout, long spinules present at inner edge, extending immediately after twisted tip; portion of distal tip shaped like golf-club end; minute spinules present at distal portion of outer edge.

Remarks. – Rathbun (1930) had regarded both E. gonagra and E. squamata as analogous species on opposite sides of the American continent, with E. gonagra on the Atlantic and E. squamata on the Pacific side. The differences between them have already been discussed under the remarks for E. gonagra . Von Prahl (1982) erroneously referred the diagram of E. squamata as Figure 10 , it should be Figure 9 instead.

Crane (1947) noted that E. squamata has a variable dark colour, from dark grayish-green to brown-black. They are often mottled with greenish or dark blue colour. The ambulatory legs are seen with bands of white or cream and purple, dark blue or brown; fingers and ocular spines furnished with burnt sienna to scarlet-orange. Often, there are two narrow violet stripes extending down two-third of the abdomen. The eyes are olive green with a brown centre.

Crane (1947) commented on the ecology of this species, noting that they are extremely common in tide pools and midtide stony zones, and can be seen feeding both under water on molluscs in tidepools as well as on tube worms out of water at night. Garth (1948) suggested that their ubiquitous nature may be due to their tolerance to a wide variety of conditions. Boone (1929) remarked that female crabs approximately 20 mm in carapace width are already ovigerous.

Distribution. – Eastern Pacific Ocean, extending from Lower California, Gulf of California to western coast of Mexico, to Gulf of Panama; Galapagos Islands.

Eriphia granulosa A. Milne-Edwards, 1880 ( Figs. 5 , 6 , 7D–G )

Eriphia granulosa A. Milne-Edwards, 1880: 339 , Pl. 56 Fig. 2–2b ; Miers, 1886: 162; Rathbun, 1902: 282; Rathbun, 1924a: 158; Boone, 1927: 234; Rathbun, 1930: 551, text–fig. 85, Pl. 224 Fig. 2–4 ; Finnegan, 1931: 646; Sivertsen, 1933: 18; Schmitt, 1939: 25; Garth, 1946: 383, Pl. 80 Fig. 2 ; Hendrickx, 1995: 95; Boschi, 2000: 80; Hickmann & Zimmerman, 2000: 121; Ng et al., 2008: 63.

Material examined. – Holotype: 1 dried female (12.0 × 17.0 mm) ( MNHN B–2447S),? Chile. Others : GALAPAGOS ISLANDS: 8 males (10.0–2.9 × 14.9– 4.1 mm), 6 females (5.2–4.3 × 8.5–5.9

mm), 4 ovigerous females (9.2–6.0 × 13.8–9.0 mm), 2 damaged ( USNM 78218), James Islands, Sullivan Bay, coll. W. L. Schmitt, 24 Jul.1938.

Type locality. – Chile (?).

Diagnosis. – Carapace transversely hexagonal, dorsal surfaces relatively flat, tuberculated anteriorly, tubercles arranged individually, decreasing in size medially, slightly pubescent anteriorly. Frontal region distinctively inflated, smooth, pubescence row behind the region. Orbit oval, deep, margin minutely denticulated; external and internal orbital spines present; supraorbital and infraorbital margins each with two longitudinal fissures. Anterolateral margin convex, with four or five acute spines. Surfaces of third maxillipeds smooth. Pterygostomial region minutely tuberculated. Suborbital region inflated. Chelipeds surface tuberculated, slightly pubescent; pubescence present at ventral margin of basis-ischium and merus; meral surfaces smooth; carpus tuberculated, tubercles joined in transverse rows; outer surfaces of chela covered with acute tubercles arranged in longitudinal rows; tubercles may be present on dactylus. Surfaces of ambulatory leg smooth, both anterior and posterior margins pubescent. Anterior male thoracic sternum smooth anteriorly. G1 relatively short stout, long spinules present at inner edge, extending immediately after twisted tip; ending in tapered acute tip.

Remarks. – The type specimen was ostensibly from Chile, although in his original description, A. Milne-Edwards (1880: 340) writes (in French) that the sole specimen he had was part of the collections of the museum and the label indicated it was from Chile. The way the sentence was written suggests that A. Milne-Edwards had doubts about its locality (D. Guinot, pers. comm.). Rathbun (1930: 551) had put a question mark against the locality in her treatment of this species, and in a separate footnote ( Rathbun, 1930: 552), she queried the Chile locality. Garth (1964) also doubted that Chile was the true type locality of this species, believing that E. granulosa was actually a Galapagos endemic.

In addition to the prominent deflexed front and two inflated frontal lobes, E. granulosa can be separated from E. gonagra and E. squamata by several other characters. On the basis of the specimens reported and presently examined, E. granulosa does not attain a size more than 20 mm in carapace width as compared to the other two species that can reach carapace widths of 70 mm. The tuberculation on E. granulosa extends to the posterior of the carapace whereas those on E. gonagra and E. squamata only reach as far as the anterior half. Eriphia granulosa also has a smooth suborbital region while in the other two species, this structure is tuberculated.

Not much variation is seen among the specimens examined, the tuberculation remaining prominent from juvenile to adult except for the increase in size of the tubercules. Eriphia granulosa seems to be a small-sized species, the largest male specimen we have is approximately 19.0 mm in carapace width and females attain maturity at about 6.0 mm. As the size increases, the tubercles on the dactylus of the cheliped also become more prominent.

Garth (1964) noted the live colour of E. granulosa : the carapace and chela are purplish-brown with apple-green markings on the cardiac region of the carapace; the presence of two longitudinal purple bands on the third maxillipeds and three on the subhepatic region; the setal row on the hepatic region is yellow; the abdominal segments are marked with purplish-brown; and the last three tubercles on the chela are white. He also commented that the species lived under rocks or in Pocillopora coral heads.

Figures

Fig. 7. Gonopods: A–C, Eriphia squamata Stimpson, 1859, male, 29.9 × 40.9 mm, USNM 17787; D–G, E. granulosa A. Milne-Edwards, 1880, male, 10.0 × 14.9 mm, USNM 78218. A, D, F, G1s; B, E, distal part of G1s; C, G, G2s. Scale bars = 1.0 mm.

Fig. 3. Gonopods: A–C, Eriphia verrucosa (Forskål, 1775), male, 50.6 × 60.4 mm, USNM 152249. D–F, E. gonagra (Fabricius, 1781), male, 26.0 × 18.7 mm, NHM 1887.23: A, D, G1s; B, E, distal part of G1s; C, F, G2s. Scale bars = 1.0 mm.

Fig. 1. Eriphia verrucosa (Forskål, 1775), male, 50.6 × 60.4 mm, USNM 152249: A, dorsal view; B, frontal view; C, ventral view.

Fig. 12. Eriphia scabricula Dana, 1852, male, 16.1 × 23.2 mm, SAM-A 12155: A–C; Eriphia sebana (Shaw & Nodder, 1803), male, 42.0 × 59.9 mm, AM-P 15678. A, D, G1s; B, E, distal part of G1s; C, F, G2s. Scale bars = 1.0 mm.

Fig. 5. Eriphia granulosaA. Milne-Edwards, 1880, holotype female (dried), 12.0 by 17.0 mm, MNHN 2447S. A, dorsal view; B, right chela; C, left chela.

Fig. 6. Eriphia granulosa A. Milne-Edwards, 1880, male, 10.0 × 14.9 mm, USNM 78218: A, dorsal view; B, frontal view; C, chelipeds.

Fig. 9. Eriphia sebana (Shaw & Nodder, 1803), neotype male, 38.5 × 53.8 mm, ZRC 1999.1020: A, dorsal view; B, frontal view; C, chelipeds.

Fig. 10. Eriphia sebana (Shaw & Nodder, 1803), male, 48.3 × 67.1 mm, AMNH 7615, holotype of Eriphia sebana hawaiiensis Ward, 1939. A, dorsal view; B, frontal view; C, ventral view.

Fig. 2. Eriphia gonagra (Fabricius, 1781), male, 18.7 × 26.0 mm, NHM 1887.23: A, dorsal view; B, frontal view; C, chelipeds; D, ventral view.