Hyastenus espinosus (Borradaile 1903)

Hyastenus espinosus is a small crab found in the Indian Ocean with a narrow carapace and short, straight horns.

"The group of forms akin to H. diacanthus (including var. elongata Ortm., 1893, H. suhinermis Zehnter, 1894, H. convexus Miers, 1884, and H. calvarius Ale, 1895) are in all likelihood no more than varieties of one variable species. The collection contains a specimen of another such form, which I describe here. The following characters, taken together, separate it from its allies mentioned above: (i) carapace narrow (10:6); (ii) gastric region swollen, with traces of the knob; (iii) horns rather less than half the length of the carapace, straight, not very divergent ; (iv) a spinule on each branchial region and a low knob in place of the intestinal spine; (v) the outer angle of the basal antennal joint not strongly marked (Borradaile 1903; pg.688)."

"The specimens, which are both males, were dredged in Haddumati Atoll in 35 and 39 fathoms (Borradaile 1903)."