Fresnerhynchus D'Acoz & Degrave 2018, gen. nov.

Genus Fresnerhynchus gen. nov.

Type species. Fresnerhynchus crozeti sp. nov., by monotypy.

Description. Rostrum long, slender, immovable, proximally armed on dorsal margin with small, movable teeth, on ventral margin with fixed teeth. Carapace not carinate behind dorsal teeth. Antennal spine large. Pterygostomial spine well developed. Supra-orbital, branchiostegal and hepatic spines absent. Hepatic pit present. Carapace with long, blunt lateral carina behind hepatic pit.

Sternal surface between bases of pereiopods 2–5 very uneven, not forming a bifid plate. Eyes large, wider than ocular peduncles. Bec ocellaire forming upward pointing elongated blunt protrusion. Stylocerite well developed, styliform. Scaphocerite well developed, significantly overreaching peduncle of antennula, blade-shaped.

Mandible with incisor process large and strongly dentate, molar process normally developed, with 3 setose ridges; well-developed tri-articulate palp.

Maxillula with palp apically produced into a setose projection, outer plate normally developed, inner plate subquadrate and fairly large.

Maxilla with long "lash" of setae projecting posteriorly from distal lobe of scaphognathite.

First maxilliped with exopod and epipod.

Second maxilliped with exopod, epipod and podobranch.

Third maxilliped very long, with exopod, epipod and two arthrobranchs.

Pereiopods without exopods. Well developed epipod present on pereiopods 1–4. Single arthrobranch on pereiopods 1–4; absent on pereiopod 5; single pleurobranch on pereiopods 1–5. Pereiopod 1 short and robust; fingers of chela with well developed brown apical spines; dactylus with longitudinal row of mobile spines on flexor border. Pereiopod 2 with long slender merus, very long slender carpus (slightly longer than merus); propodus less than half as long as carpus, slender; chela minute, with well developed apical teeth; dactylus with longitudinal row of mobile spines on flexor border. Pereiopods 3–5 moderately long, rather slender, with all articles normally developed (propodus not shortened, longer than carpus); merus with strong spines, dactylus adorned with spines on flexor border.

Pleonites dorsally not carinate, posterodorsally neither toothed nor produced. Pleuron of pleonite 4 with posteroventral corner not produced into a tooth. Pleuron of pleonite 5 with tooth on upper 0.3 of posterior margin, posteroventral corner produced into a tooth.

Telson long and narrow, equal to uropods, with series of large dorsolateral spines.

Etymology. Fresnerhynchus is a combination of ' Fresne ' and '- rhynchus '. ' Fresne ' honours the French explorer Marc-Joseph Marion du Fresne (22 May 1724 – 12 June 1772), who discovered the Archipel Crozet, which is close to the type locality of the type species of the genus. The suffix '- rhynchus ' means having a snout, bill, beak or rostrum. It alludes to the very long rostrum of the shrimp and rhymes with the vaguely similar genus Cinetorhynchus (Rhynchocinetidae). The name is masculine.

Remarks. Fresnerhynchus is superficially similar to Lipkius. However, the absence of a sternal plate between the pereiopods (vs. present in Lipkius) and the presence of spines on the flexor border of the dactylus of walking pereiopods (vs. absent in Lipkius) justifies the recognition of a separate genus. The new genus also exhibits some morphological similarity to the genus Eugonatonotus (family Eugonatonotidae), especially in the shape of the rostrum and the large eyes. But it is clearly separated from that family by the absence of ridges on the carapace as well as the absence of exopods on the pereiopods.