Richalpheus palmeri, n. gen., n. sp., an infaunal alpheid shrimp from the philippines, with redescription of Amphibetaeus jousseaumei (Coutiere, 1896) (Decapoda : Caridea)

A new alpheid shrimp genus, Richalpheus, new genus, is established for R. palmeri, new species, from Panglao, Philippines, and based on a single specimen collected from a presumed thalassinidean burrow in a shallow lagoon. Richalpheus appears to be most closely related to Amphibetaeus Coutiere and Leptalpheus Williams (sensu lato). Richalpheus and Amphibetaeus share the presence of a non-functional fossa-tooth system on the fingers of the major cheliped, but the new genus differs from Amphibetaeus by the absence of pereiopodal epipods and the presence of only four segments in the carpus of the second pereiopod. The syntypes of Amphibetaeus jousseaumei, a species not collected since the original description by Coutiere, remain untraceable except for one major cheliped. Amphibetaeus jousseaumei is redescribed based on the original descriptions and illustrations of Coutiere scattered in older French publications, and on the newly rediscovered, diagnostic major cheliped, which is designated as lectotype of A. jousseaurnei.