Sternostylus defensus ( Benedict, 1902 )

Baba, Keiji & Wicksten, Mary K., 2019, Chirostyloidean squat lobsters (Crustacea: Decapoda: Anomura) from the Galapagos Islands, Zootaxa 4564 (2), pp. 391-421 : 418-419

Sternostylus defensus ( Benedict, 1902)

(Fig. 18)

Ptychogaster defensa Benedict, 1902: 299 , fig. 44 (type locality: Galapagos Islands, between Santa Cruz and San Cristobal Islands, 00°29'00"S, 89°54'30"W, 717 m).—Baba et al. 2018: 81. Gastroptychus defensa .— Baba & Haig 1990: 856, fig. 3 (note on syntypes).

Remarks. The specimen examined matches both the original description and the note provided by Baba & Haig (1990) on the syntypes, although the carapace spines are much sharper in this specimen. The spines on the P1 carpus also are more numerous and sharper than in the syntypes. These differences in the spination between the present male and the syntype male (CL 23.9 mm vs. 12.9 mm) are likely to be size-related.

The specimen was collected together with Uroptychus occidentalis (see above). The photo (Fig. 19) shows the collected specimen on an antipatharian (black coral) next to a gorgonian, Chrysogorgia sp. but it is not certain on which of the two corals the squat lobsters were originally resting. The in-situ photo in Bell et al. (2016: 2) shows an unidentified squat lobster, which is very much like this species, on a black coral. According to Le Guilloux et al. (2010), adults of Sternostylus formosus (as Gastroptychus formosus ) were found on gorgonian and antipatharian corals, but the black coral Leiopathes sp. was preferred.

Five species of Sternostylus are known from the eastern Pacific. Distinguishing characters among these species are shown in the key to species in Baba (2005).

Distribution. Galapagos Islands between Santa Cruz and San Cristobal Islands, and now at East Wolf Seamount; at depths of 717– 973 m.