The genus Richapheus presently includes two species.
Richalpheus palmeri Anker and Jeng, 2006, the type species.
Richalpheus dahabensis Anker and Dworschak, 2007.
Richalpheus may be separated from other alpheid genera by the combination of following characters:
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Frontal margin of carapace without rostrum or orbital teeth; eyes concealed in dorsal view.
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Absence of strap-like epipods (mastigobranchs) from coxae of the third maxilliped and all pereiopods.
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Unequal and asymmetrical enlarged chelipeds capable of flexion (folding); major cheliped with or without shallow fossa on pollex, distinct snapping mechanism absent.
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Second pereiopod with four-segmented carpus.
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Sixth abdominal somite (pleomere) with more or less distinct articulated plate.
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Third maxilliped with acutely produced lateral plate.
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Uropodal diaeresis (transverse suture) with large mesial tooth. |
Richalpheus appears to be restricted to the Indo-West Pacific. This genus shares many characters with Leptalpheus (s. lat.), Fenneralpheus, and Amphibetaeus, differing from these genera by the absence of mastigobranchs on the pereiopods and the four-segmented carpus of the second pereiopod (with one exception).
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