Pagurixus Melin, 1939

Komai, Tomoyuki, 2010, New species and new records of the hermit crab genus Pagurixus Melin, 1939 (Crustacea: Decapoda: Anomura: Paguridae) from the Indo-West Pacific, Journal of Natural History 44 (21 - 22), pp. 1269-1342 : 1270

Genus Pagurixus Melin, 1939

Remarks

It has been reported that some species of Pagurixus have a collar-like protrusion located on the posteromesial portion of the right coxa of the fifth pereopod in males (Komai and Myorin 2005; Komai and Osawa 2006). Komai and Osawa (2006) termed this structure “posteromesial protrusion”. The presence of this protrusion is now confirmed in the following nine species (although the developmental degree of it is rather variable according to species): P. boninensis ; P. concolor ; P. crosnieri sp. nov.; P. fasciatus ; P. festinus McLaughlin and Haig, 1984 ; P. paulayi Komai and Osawa, 2006 ; P. pilosus sp. nov.; P. pseliophorus Komai and Osawa, 2006 ; and P. purpureus Komai and Osawa, 2009 .

The ventromesial protrusion is well calcified and its base is clearly demarcated by a suture; the gonopore opening is located at the top of this protrusion; setae comprising the tuft, being characteristic of the genus, arise adjacent to the margin of the gonopore. Therefore, it cannot be considered that the protrusion is a modification of the vas deferens or of a part of the gonopore. The function of the protrusion remains unknown. No other pagurids have a similar structure.