Guinearma, Shahdadi & Schubart, 2018

GUINEARMA View in CoL GEN. NOV.

Type species: Grapsus huzardi Desmarest, 1825 , by present designation.

Diagnosis: Medium to large sized crabs (up to 5 cm carapace width among the studied material). Carapace squarish (slightly broader than long), carapace regions well defined, frontal region four-lobed, median groove extending to gastric region, gastric region defined (meso- and metagastric region distinguishable), cardiac and intestinal regions marked, lateral margins of the carapace with two teeth or indentations, the posterior one being smaller. Male chelipeds robust, palm with one oblique or curved row of pectinated crest on the dorsal surface, the crest consisting of short and thick teeth, followed by a line of small granules proximally, dorsal surface of the chelar dactylus with low tubercles. Walking legs relatively flat. Pleon of males relatively long, triangular, somite 3 widest; telson small, longer than wide. Male press button small, but distinct. Female vulvae are located in stenite 5 with elongated opercula almost parallel to sternal sutures, the innermost part reaching the sternal suture between sternite 4 and 5, accompanied by a small sternal cover on the anterolateral corner.

Etymology: The name Guinearma is composed of two parts: Guinea is derived from the Gulf of Guinea, the main distribution area of the genus and - arma has become a typical ending for new genera in the family Sesarmidae , making reference to the type genus Sesarma . Gender neuter.

This genus includes three species as follows (the synonym (after =) and original combinations [in square brackets] are adopted from Ng et al., 2008):

Guinearma alberti ( Rathbun, 1921) View in CoL comb. nov. [ Sesarma (Chiromantes) ]

Guinearma huzardi ( Desmarest, 1825) View in CoL comb. nov. [ Grapsus View in CoL ]

= Sesarma africana H. Milne Edwards, 1837 View in CoL

Guinearma kamermani ( De Man, 1883) View in CoL comb. nov. [ Sesarma View in CoL ( Chiromantes View in CoL ]

Remarks: Grapsus huzardi was selected as type species of the genus, because it is the first described species among its congeners, as well as the more common and more frequently reported species (see Monod, 1956; Manning & Holthuis, 1981). These three species were previously considered members of Perisesarma (see Ng et al., 2008). Among them, G. kamermani is a poorly known species and was originally described based on one male specimen and without further reports. As we have examined more material, a comparative description of the three Guinearma species is now in preparation to facilitate their identifications and will be published elsewhere.