Pachycheles biocellatus ( Lockington, 1878 )

Ferreira, Luciane Augusto De Azevedo & Anker, Arthur, 2021, An annotated and illustrated checklist of the porcelain crabs of Panama (Decapoda: Anomura), Zootaxa 5045 (1), pp. 1-154 : 45-47

Pachycheles biocellatus ( Lockington, 1878)

( Fig. 21 )

Petrolisthes (Pisosoma) biocellatus Lockington 1878: 396 , 403.

Pachycheles biocellatus . — Glassell 1937: 84; Haig 1957b: 4; Haig 1960: 144, pl. 32, fig. 1; Haig 1968: 68; Gore & Abele 1976: 19; Gore 1982: 7; Werding & Haig 1982: 64; Lazarus-Agudelo & Cantera-Kintz 2007: 229; García-Madrigal & Andréu- Sánchez 2009: 28, fig. 2D; Moscoso 2012: 76.

Petrolisthes (Pisosoma) gibbosicarpus Lockington 1878: 396 , 402.

(?) Not Pachycheles biocellatus .—Hickman & Zimmeran 2000: 67, unnumbered colour photograph; Hickman 2009: 34, fig. 3 [= Pachycheles sp. ].

(?) Pisosoma aphrodita Boone 1932: 53 , figs. 17, 18.

Material examined. Panama [Pacific]: 2 females, cl 3.2, cw 3.4 and cl 4.7, cw 5.6 ( FLMNH UF 57125 ), Coiba Is ., Isla Afuera , 7°41’42.9”N, 81°38’08.6”W, rocky intertidal and adjacent subtidal with coral rubble and dead coral heads, in crevices of coral rocks, depth: 0–1 m, leg. A. Anker, 19.02.2019 (fcn PAN-107); 2 males, cl 4.6, cw 5.0 and cl 4.9, cw 5.3 ( FLMNH UF 57703 ), Coiba Is ., Isla Coiba , northwest coast, small rocky island off Bahía Santa Cruz, 7°37’53.4”N, 81°46”44.9”W, rocky plateau, under rocks and in rock crevices, leg. M. Leray et al., 20.02.2019 (fcn PAN-151); 1 ov. female, cl 5.3, cw 6.0, 1 male, cl 4.8, cw 5.2 ( MZUSP 33447 ), Punta Mala, rock-sand intertidal, under rocks and in rock crevices, leg. A. Anker & J.F. Lazarus-Agudelo, 23.03.2015. Extra-limital material . Colombia [Pacific]: 1 ov. female, cl 6.3, cw 7.1 (CRBM-UV-cr:2009-105), Los Negritos off Bahía Málaga, 03°53’47.5”N, 77°24’09.8”W, depth 0–1 m, large rocky outcrop with large boulders, under large rocks, many cemented by sponges, on coarse sand, leg. A. Anker, 27.04.2009 (fcn COL-249) .

Previous records from Panama. Haig (1960); Gore & Abele (1976); Gore (1982).

Distribution. East Pacific: Mexico, Costa Rica, Panama (Coiba Is., Punta Mala, Taboga Is., Las Perlas Is.), Colombia, Ecuador (possibly not including Galápagos, see below) and Peru ( Haig 1960; Gore & Abele 1976; Gore 1982; Moscoso 2012; present study).

Ecology. Intertidal and shallow subtidal, known depth range: 0–26 m; on rocky and mixed rocky-sandy shores and adjacent rocky bottoms; typically under rocks and in rock crevices, also in dead corals or sponges ( Haig 1960; García-Madrigal & Andréu-Sánchez 2009; present study).

Remarks. Pachycheles biocellatus is the eastern Pacific counter-part of the western Atlantic P. riisei ( Stimpson, 1859) (see below) and P. meloi Ferreira & Tavares, 2017 , with only the former of them reported from the Caribbean coast of Panama (see below). Pachycheles biocellatus differs from P. riisei by the carapace dorsally rather flattened (vs. markedly swollen in P. riisei ); the carapace front slightly prominent, dorsally not overreaching the orbits (vs. strongly prominent, overreaching the orbita in P. riisei ); and the ventral surface of the P2–P4 dactyli armed with row of three spines (vs. with five spines in P. riisei ). The Pacific species differs from P. meloi by the absence of pleopods in males (vs. with a pair of well-developed pleopods on the second male pleonite) ( Ferreira & Tavares 2017).

Haig (1960) provided a very detailed description of the colour pattern of P. biocellatus , which corresponds well to the colour photograph of a Mexican specimen in García-Madrigal & Andréu-Sánchez (2009), as well as to that of the Panamanian and Colombian specimens ( Fig. 21 ). The uniformly carmine-red carapace with two large whitish or pinkish blotches on the anterolateral (epibranchial) surface of the carapace, just posterior to the base of the antennae, and two smaller croissant-shaped white spots, each lateral to the cardiac area, as well as the deep carmine-red P1 with white fingertips, are very diagnostic of the species.

The specimen from Galápagos identified as P. biocellatus in Hickman & Zimmerman (2000) and Hickman (2009), with a very different, brown-orange mottled carapace and P1, is most likely not P. biocellatus . It may correspond to the species described by Boone (1932) as Pisosoma aphrodita Boone, 1932 based on material from Galápagos, and subsequently placed in the synonymy of P. biocellatus by Glassell (1937), or belong to another, perhaps undescribed taxon.

Figures

FIGURE 21. Pachycheles biocellatus (Lockington, 1878): A, B, male (cl 4.8 mm, cw 5.2 mm) from Punta Mala, Panama (MZUSP 33447), dorsal (A) and ventral (B) views [photographs by AA].