Cryptodromia fallax (Latreille, in Milbert, 1812)

Devi, S. Suvarna, Mendoza, Jose C. E., Ravinesh, R., Idress Babu, K. K., Kumar, A. Biju & Ng, Peter K. L., 2019, On a collection of brachyuran crabs from Lakshadweep, Indian Ocean (Crustacea: Decapoda: Brachyura), Zootaxa 4613 (3), pp. 477-501 : 478-479

Cryptodromia fallax (Latreille, in Milbert, 1812)

( Fig. 2A )

Material examined. 1 male (5.6 x 5.0 mm) ( DABFUK), Minicoy, 29 August 2013 ; 1 male (7.1 x 6.4 mm) ( DAB- FUK), Kavaratti, 7 November 2013 ; 1 ovigerous female (7.3 x 6.1 mm) ( DABFUK), Kilton, 22 October 2014 .

Comparative material: Guam — 1 ovig. female (7.2 x 6.5 mm) (ZRC 2000.0751), Gun Beach, fore reef, 3–5 m depth, at night, coll. L. Kirkendale, 5 July 1999, det. C. McLay, Apr. 2000; Philippines — 1 male (9.2 x 8.3 mm) ( ZRC 2011.0891 ), Panglao I., Gak-ang, stn. M18, 0–1 m depth, coll. PANGLAO 2004 Expedition, 10 & 12 June 2004 , det. C. McLay, ca. 2011; Vanuatu — 1 male (6.3 x 5.9 mm) ( ZRC 2011.0909 ), stn. DB80, Bruat Channel , 18 m depth, sand & corals on submarine hill, coll. SANTO 2006 Expedition, 2 October 2006 ; 1 female (7.0 x 5.7 mm) ( ZRC 2011.0902 ), stn. VM36, south of Aés I., intertidal, coll. SANTO 2006 Expedition, 25 Sep. 2006 ; 1 male (8.5 x 8.0 mm) ( ZRC 2011.0904 ), stn. VM58, Palikulo Peninsula , intertidal, coll. SANTO 2006 Expedition, 7 October 2006 ; all det. C. McLay, ca. 2011.

Remarks. Cryptodromia hirsuta was described by Borradaile (1903) from the Maldives and has since been synonymized under C. fallax (Latreille, in Milbert, 1812) , described from Réunion Island ( McLay 1993, 2003). Examination of the type material of C. fallax and representative specimens in the ZRC, suggests that it is probably a species complex. The neotype of C. fallax is deposited in the MNHN ( Cleva et al. 2007: 240, fig. 7C), and the shape of the carapace and the dentition of the anterolateral margins differ with the present material from Lakshadweep ( Fig. 2A ). The carapace of the neotype is more globose and the first two anterolateral teeth are distinctly separated. In the Lakshadweep material, the carapace is relatively flatter and more trapezoidal in outline, with the first two anterolateral teeth fused. Likewise, Borradaile’s figure of C. hirsuta (Borradaile, 1903: pl. 33 fig. 3A) shows the first two anterolateral teeth separate from each other. In all three cases, the median rostral tooth is not much narrower than the adjacent lateral teeth. The Lakshadweep specimens, however, are smaller than the types of C. fallax (CW: 13.3 mm) or C. hirsuta (CW: 8.0 mm), which could explain the minor differences in morphology. We therefore, follow McLay’s (1993) synonymization of C. hirsuta Borradaile under C. fallax (Latreille) for the time being.

More substantial differences distinguish the Lakshadweep specimens from C. fallax collected from the western Pacific (e.g. Guam and Vanuatu): the median rostral tooth is only slightly narrower than the two lateral teeth (versus median tooth much narrower than the laterals in the Pacific material), the supraorbital teeth are relatively blunt and positioned closer together (versus more acute and spaced further apart in the Pacific material), and the infraorbital tooth is subtruncate (versus more acutely triangular in the Pacific material). It is very likely that the Pacific material is not conspecific with C. fallax ; this will require a more thorough examination of the available material and synonyms, which are beyond the scope of the present work.

This species has been recorded from Lakshadweep by Dev Roy & Nandi (2005). Among the present specimens, the smaller male (5.6 x 5.0 mm) from Minicoy was collected carrying a colonial ascidian.

Figures

FIGURE 2. A, Cryptodromia fallax, male, 7.1 x 6.4 mm (DABFUK), Kavaratti; B, Gonioinfradens paucidentatus, female, 35.9 x 27.0 mm (DABFUK), Agatti; C, Xiphonectes iranjae, male, 24.7 x 11.6 mm (DABFUK), Agatti; D, Euxanthus rugosus, juv. male, 10.3 x 6.8 mm) (DABFUK), Kavaratti, 7 January 2013; E, Juxtaxanthias lividus, male 43.5 x 27.2 mm (DABFUK), Kavaratti; F, Lachnopodus bidentatus, male, 14.0 x 9.3 mm (DABFUK), Minicoy; G, Macromedaeus crassimanus, male, 34.7 x 22.1 mm (DABFUK), Kavaratti, 10 October 2014; H, Percnon sp., megalopa, 6.9 x 5.1 mm (DABFUK), Kavaratti. Scale bar: 5.0 mm.