Additions to the genus Phycomenes Bruce, 2008 (Crustacea: Decapoda: Pontoniinae)

Abstract

The genus Phycomenes was recently described by Bruce (2008)) for a small sea-grass inhabiting shrimp, Phycomenes zostericola Bruce, 2008, from south-east Queensland, Australia. The close similarity of this species to Periclimenes indicus (Kemp 1915) was noted. Subsequently specimens of Kemp’s species from the type locality, Chilka Lake, Orissa, India, were examined and the most characteristic features of the genus Phycomenes were found to be present, i.e., a transverse triangular median process on the fourth thoracic sternite and the greatly reduced size of the second pereiopods in comparison with other Periclimenes species, with a very well developed ocular ocellus. Periclimenes indicus is therefore transferred to the genus Phycomenes Bruce. Periclimenes cobourgi Bruce & Coombes, 1995 has also been noted as closely similar to Periclimenes indicus, showing the same major features and should also be considered as congeneric with Phycomenes zostericola. Similarly, examination of specimens of Periclimenes sulcatus Ďuriš, Horká, & Marin, 2008, and P. siankaanensis Martínez-Mayén, & Román-Contreras, 2006, kindly donated by Dr Zdenek Ďuriš and Dr Mario Martinez-Mayén to the Queensland Museum, Brisbane, show the same features and should be similarly placed in the genus Phycomenes. Martínez-Mayén and Román-Contreras (2006) considered P. siankaanensis to be a member of the “iridescens” species complex, including also P. iridescens Lebour, 1949, P. platalea Holthuis, 1951, P. antipathophilus Holthuis & Eibl-Eibesfeldt, 1964, P. patae Heard & Spotte, 1991, and P. mclellandi Heard & Spotte, 1997. Periclimenes platalea has recently been removed from this complex and placed in the genus Rapipontonia Marin by Marin (2007). No examples of these species have been examined but it seems likely that some may possibly be better placed in Phycomenes. Some of these taxa have been reported as associates of coelenterate hosts rather than from sea-grass habitat, but such a coelenterate association has also been reported in the case of the holotype specimen of P. cobourgi found on a gorgonian host. The specimens of P. indicus were kindly donated by the Zoological Survey of India, Calcutta (ZSI). The specimens examined are deposited in the collections of the Northern Territory Museum, Darwin (NTM) and Queensland Museum, Brisbane (QM).