Flagitopisa fluviatilis (Stock) Sawicki & Holsinger & Sket, 2005

Sawicki, Thomas R., Holsinger, John R. & Sket, Boris, 2005, Redescription Of The Subterranean Amphipod Crustacean Flagitopisa Philippensis (Hadzioidea: Melitidae), With Notes On Its Unique Morphology And Clarification Of The Taxonomic Status Of Psammogammarus Fluviatilis, Raffles Bulletin of Zoology 53 (1), pp. 59-68 : 66

publication ID	https://doi.org/ 10.5281/zenodo.4619049
DOI	https://doi.org/10.5281/zenodo.4618917
persistent identifier	https://treatment.plazi.org/id/A12187C9-5366-FFC3-FCBD-FE44FB17FA29
treatment provided by	Carolina
scientific name	Flagitopisa fluviatilis (Stock)
status	comb. nov.

Treatment

Flagitopisa fluviatilis (Stock) View in CoL , new combination

Psammogammarus fluviatilis Stock, 1991:227-233 View in CoL . [type-locality: Pagsanjan Falls, Laguna Province, Luzon Island, Philippines].

Material Examined. – PHILIPPINES. 6 paratypes (Zoological Museum, Amsterdam University, ZMA AMPH. 108811) from interstices in coarse sand on bank of Pagsanjan Falls, Laguna Province, Luzon Island .

Diagnosis. – Flagitopisa fluviatilis is morphologically closely similar to F. philippensis and distinguished from the latter primarily by overall smaller body size and length and spination of uropod 3. Otherwise corresponding to the diagnosis given by Stock (1991).

Remarks. – Stock (1987) questioned the diagnosis of the monotypic genus Flagitopisa by Karaman (1984) on the premise that this genus was described largely on the basis of plesiomorphic characters. Stock (1991) described the new species Psammogammarus fluviatilis and noted the presence of a large “coxal” gill on pereopod 7. Examination of the paratypes of P. fluviatilis during this study indicates that the gill is attached to the ventral surface of the first pleonal segment (pleonite 1), just anterior to pleopod 1. Psammogammarus fluviatilis and F. philippensis are synapomorphic for this highly unusual character and are otherwise morphologically very similar. Based on its overall morphological similarity to F. philippensis and possession of this highly unusual pleonal gill, P. fluviatilis is reassigned to Flagitopisa . Despite the rejection of the genus Flagitopisa by Stock (1987), the name Flagitopisa is available according to the International Code of Zoological Nomenclature and is therefore used here for this unique genus.