{{Short description|Genus of crustaceans}} {{Automatic taxobox | image = | image_caption = | display_parents = 4 | taxon = Protognathia | authority = Wägele & Brandt, 1988 | type_species = ''Cirolana bathypelagica'' | type_species_authority = Schultz, 1977 }}
'''''Protognathia''''' is a genus of marine isopods belonging to the monotypic family '''Protognathiidae'''.<ref name="GBIF">{{cite web |title=Protognathia Wägele & Brandt, 1988 |url=https://www.gbif.org/species/2207614 |website=www.gbif.org |access-date=23 June 2021 |language=en}}</ref>
The species of this genus are found in southernmost South Hemisphere,<ref name="GBIF" /> more specifically in the Weddell Sea, where the type specimen was found at a water depth from 410 to 245 meters.<ref name=":0">{{Cite journal |last=Wägele |first=Johann-Wolfgang |last2=Brandt |first2=Angelika |date=1988-05-01 |title=Protognathia n. gen. bathypelagica (Schultz, 1977) rediscovered in the Weddell Sea: A missing link between the Gnathiidae and the Cirolanidae (Crustacea, Isopoda) |url=https://doi.org/10.1007/BF00442027 |journal=Polar Biology |language=en |volume=8 |issue=5 |pages=359–365 |doi=10.1007/BF00442027 |issn=1432-2056|url-access=subscription }}</ref>
== Species == The Genus contains the following species:<ref name="GBIF" />
*''Protognathia bathypelagica'' {{small|(Schultz, 1977)}} *''Protognathia waegeli'' {{small|Kussakin & Rybakov, 1995}}
== Description == Isopods of this family (and genus respectively) are a morphologic intermediate between members of Gnathiidae and Cirolanidae, which is why the type species, ''Protognathia bathypelagica'', was at first misidentified as ''Cirolana bathypelagica''.<ref>{{Cite WoRMS|title=''Protognathia'' Wägele & Brandt, 1988|id=175131|access-date=10 July 2025|db=Isopod}}</ref> Their pleonites are not fused. Pereonites four to six are larger than the remaining segments, and the seventh pereonite is about as large as a pleonite. The seventh pereopod is absent. The uropods are flat and slender, almost as long as the pleotelson. Members of this genus have a tail fan and lack eyes. All pleopods have similar outlines, with large branches.<ref name=":0" />
== Ecology == While its mandibles resemble those of cirolanid isopods, it is not used as a cutting instrument, as they have a pronounced point probably used for stinging. This then suggests a bloodsucking, ectoparasitic ecology.<ref name=":0" />
==References== {{Reflist}}
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Category:Isopod genera Category:Cymothooidea
{{Cymothoida-stub}}