Megalobrachium tuberculipes ( 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 : 38-39

Megalobrachium tuberculipes ( Lockington, 1878)

( Fig. 16 )

Pachycheles tuberculipes Lockington 1878: 396 , 404. Polyonyx tuberculipes .— Nobili 1901: 21. Pisonella tuberculipes . — Glassell 1938: 437, 440, pl. 34, fig. 1. Porcellanopsis tuberculipes . — Chace 1942: 100. Megalobrachium tuberculipes . — Haig 1960: 213, 227, pl. 16, fig. 11, pl. 40, fig. 4; Haig 1968: 72; Haig et al. 1970: 24; Gore

& Abele 1976: 18, fig. 3 (lower 2 figures); Lazarus-Agudelo & Cantera-Kintz 2007: 229; Hiller & Lessios 2019: 414, fig.

1l, m.

Material examined. None from Panama. Extra-limital material. Colombia [Pacific]: 1 male, cl 2.5, cw 2.8 (CRBM- UV-cr:2009-109), Bahía Málaga , Islote Morro Chiquito off Juanchaco, 03°55’20.9”N, 77°20’54.7”W, depth 3 m, rock-sand bottom, ARMS, leg. J.F. Lazarus-Agudelo, 28.04.2009 (fcn COL-320) .

Previous records from Panama. Haig (1957b, 1960); Gore & Abele (1976); Hiller & Lessios (2019).

Distribution. East Pacific: Mexico, Panama (Las Perlas Is., Achotines on Azuero Peninsula), Colombia and Ecuador ( Haig 1968; Gore & Abele 1976; Hiller & Lessios 2019; however, see below).

Ecology. Intertidal and shallow subtidal, presently known depth range: 0–20 m, typically 2–8 m; under rocks or associated with sponges and corals ( Haig 1968; Lazarus-Agudelo & Cantera-Kintz 2007).

Remarks. Megalobrachium tuberculipes seems to be a rarely collected species, possibly because of its small size and cryptic colour pattern, and perhaps most importantly, for its preference for subtidal habitats. Glassell (1938) described the carapace of M. tuberculipes in life as “muddy grey, with a dark patch on the central regions”. This description, albeit very superficial, does not correspond well to the colour patterns of a greyish Mexican specimen and a reddish Panamanian specimen, both with a broad pale longitudinal band and two dark spots in the central posterior region of the carapace, in Hiller & Lessios (2019: fig. 1l, m). Based on this discrepancy in the colour patterns and existence of three genetically distinct clades, it is highly likely that M. tuberculipes contains more than one species (Hiller & Lessios 2019). The herein illustrated specimen from Bahía Málaga, Colombia ( Fig. 16 ), agrees well with the specimen from the Azuero Peninsula in Hiller & Lessios (2019).

Genus Minyocerus Stimpson, 1858

Figures

FIGURE 16. Megalobrachium tuberculipes (Say, 1818): extra-limital specimen, male (cl 2.5 mm, cw 2.8 mm) from Bahía Málaga, Colombia (CRBM-UV-cr:2009-109), dorsal view.