Glyptoxanthus meandrinus ( Klunzinger, 1913 )

Mendoza, Jose Christopher E. & Guinot, Danièle, 2011, Revision of the genus Glyptoxanthus A. Milne-Edwards, 1879, and establishment of Glyptoxanthinae nov. subfam. (Crustacea: Decapoda: Brachyura: Xanthidae), Zootaxa 3015, pp. 29-51 : 45

Glyptoxanthus meandrinus ( Klunzinger, 1913)

( Fig. 9A, B )

Actäa ( Psaumis ) mäandrina Klunzinger, 1913: 185 [89], pl. 1 fig. 5, pl. 6 fig. 4 (type locality: Kosseir, Red Sea). Actaea vermiculata, Odhner 1925: 57 , pl. 4 fig. 1. Not Cancer vermiculatus Lamarck, 1818 .? Glyptoxanthus meandrinus , Guinot 1971: 1073.

Glyptoxanthus meandrinus, Guinot 1967: 556 ; 1979: 68, pl. 6 fig. 7. — Serène 1984: 83.

Material examined. None. The only known specimen is the type, supposedly deposited in the Stuttgart Museum.

Diagnosis. (Modified from Klunzinger (1913)) Carapace transversely ovate, width-to-length ratio 1.5; regions more-or-less defined, intervening furrows wide, especially cervical furrow; 2M nearly completely divided except for fused anterior section with 1M; 3M fused to inner branch of 2M posteriorly; 4M bridging 3M and 1P; 2L, 3L, 4L distinct, 5L and 6L fused, distinct oblongate cavity on 5L; 1P with 2 parallel, transverse furrows; 2P X-shaped, entire; vermiculations narrow, rough, anfractuous. Front quadrilobate. Anterolateral margins arcuate, divided into 4 distinct lobes, posterior 3 triangular, last acutely so. Male thoracic sternum regularly eroded, with near-symmetric pattern of cavities and ridges. External surfaces of pereopods with similar sculpturing as dorsal carapace. Abdomen with transverse bars. G1 and G2 unknown.

Remarks. Klunzinger (1913) described Actäa ( Psaumis ) mäandrina (= Actaea meandrina ), from Kosseir (= Al-Qusair), on the Egyptian coast of the Red Sea, and from only one small specimen, “size: 6 mm ”, of indeterminate sex. This species was considered by Odhner (1925) as a juvenile Actaea vermiculata ( Lamarck, 1818) , and he also cast some doubt as to the real provenance of Lamarck’s types, which were supposedly from the Caribbean region. Guinot (1979), however, contradicted this and provided evidence that Glyptoxanthus vermiculatus can indeed be found in the Caribbean Sea. She further commented on the disjunct distributional pattern of G. vermiculatus and G. meandrinus , which strongly suggested that the two were distinct species. This opinion was also held by Serène (1984), who included G. meandrinus in his list of the crabs of the Red Sea and the western Indian Ocean. In the absence of additional specimens from the Red Sea, Glyptoxanthus meandrinus is also considered as distinct from G. vermiculatus in the present work. Although the holotype, deposited in the Stuttgart Museum (see Odhner 1925; Serène 1984), was not available for examination, the figures provided by Klunzinger (1913) and Odhner (1925) were sufficiently clear to make comparisons. Glyptoxanthus meandrinus differs from G. vermiculatus primarily by the narrower, simpler vermiculations and the wider grooves and furrows on the dorsal carapace surface (vermiculations thicker and more convoluted, and intervening furrows much narrower in G. vermiculatus ), and by the presence of a distinct oblongate cavity on the 5L subregion (absent in G. vermiculatus ).

Ecology and geographical distribution. Klunzinger (1913: 186 [90]) described the colouration of this species as “… white, including the fingers in their whole length” [translated]. It is known only from the type locality. Very little else is known about this rare species.

Figures

FIGURE 9. A – B, Glyptoxanthus meandrinus (Klunzinger, 1913), holotype, male, 9.0 × 6.0 mm (Strasburg Museum), after Odhner (1925): A, dorsal view, B, ventral view. C – F, Glyptoxanthus vermiculatus (Lamarck, 1818), lectotype, male, 41.8 × 28.6 mm (MNHN-B 3016), Caribbean Sea: C, dorsal view, D, anterior view, E, posteroventral view, F, left chela, external view.