Tutankhamen cristatipes (A. Milne-Edwards, 1880)

Mclay, Colin L., 2009, Revision of the crab genus Garthambrus Ng, 1996, with the description of two new genera and discussion of the status of Tutankhamen Rathbun, 1925 (Crustacea: Brachyura: Parthenopidae), Zootaxa 2122, pp. 1-50 : 40-41

Tutankhamen cristatipes (A. Milne-Edwards, 1880)

( Figs 21 , 22 A–D)

Mesorhoea cristatipes A. Milne-Edwards, 1880 a: pl. 31A figs 6–6c; 1880b: 352; 1880c: 5; A. Milne-Edwards & Bouvier 1923: 359, pl. 10 fig. 3.

Lambrus cristatipes — Rathbun 1898: 261.

Tutankhamen cristatipes — Rathbun 1925: 530, pl. 277 figs 3–5. – Ng et al., 2008: 132.

Type material. HOLOTYPE: male 16.9 x 13.5 mm ( MCZ 8943), Blake Expedition 1878–79, stn 269, Caribbean Sea, Windward Is, off St. Vincent, 13º07’36”N, 61º05’36”W, 227 m, A. Agassiz coll., 3 Mar 1879. Diagnosis. As for generic diagnosis.

Distribution. Known only from the Caribbean Sea: Windward Is and Pourtales Plateau. Depth range 227–366 m (Rathbun, 1925).

Remarks. It is intriguing to note that the species closest in appearance to T. cristatipes is G. pteromerus from the Pacific. Both species have relatively smooth carapace surface, which are sub-triangular in shape, but G. pteromerus is relatively much wider CW/CL = 1.35–1.55 vs 1.25 for T. cristatipes . Both species have strong cristae on the upper and lower margins of the ambulatory legs and also have the proximal half of the cheliped merus outer margin dentate, but with the distal half being entire.

This poses some interesting questions about the relationship between Tutankhamen and Garthambrus . Garthambrus pteromerus is actually atypical of most Garthambrus species, having a relatively smooth carapace surface albeit somewhat pitted. But, most importantly, it has a relatively smooth and entire pterygostomial ridge, which is similar to that of Tutankhamen . However, it is not as expanded as that of T. cristatipes and never visible dorsally in G. pteromerus . As such, G. pteromerus may be possibly a link between Garthambrus and Tutankhamen . However, the easternmost record of G. pteromerus is in the Philippines, a considerable distance from the Caribbean Sea. Alternatively G. lacunosus , which is superficially very similar to G. pteromerus , from Hawaii, is another possible link. This could possibly due to the paucity of sampling because there are very few deep-sea samples from around the Hawaiian Is. Furthermore, very few specimens of T. cristatipes have been reported. The relationship between Garthambrus and Tutankhamen thus, remains unclear, but future discoveries and molecular studies could result in changes such that Tutankhamen includes species that have an Eastern Pacific/Caribbean distribution.

Figures

FIGURE 21. Gonopods: (A, B) Tutankhamen cristatipes (A. Milne-Edwards, 1880): holotype, male 16.9 x 13.5 mm (MCZ 8943), Caribbean Sea, off St. Vincent. Scale bar = 1 mm. A, right G 1; B, right G 2.

FIGURE 22. Tutankhamen cristatipes (A. Milne-Edwards, 1880): A – D, holotype, male 16.9 x 13.5 mm (MCZ 8943), Caribbean Sea, off St. Vincent. — Garthambrus pteromerus (Ortmann, 1893): E – H, male 19.2 x 13.4 (ZRC), Philippines, Visayas, Bohol, Panglao, Balicasag I. A, E, carapace, dorsal surface; B, F, epistome; C, G, sternum and abdomen; D, H, side profile.