Bircenna hinojosai, Hughes, Lauren Elizabeth & Loerz, Anne-Nina, 2019

Hughes, Lauren Elizabeth & Loerz, Anne-Nina, 2019, Boring Amphipods from Tasmania, Australia (Eophliantidae: Amphipoda: Crustacea), Evolutionary Systematics 3 (1), pp. 41-52 : 41

Bircenna hinojosai sp. nov. Figs 1, 2, 3

Type material.

Holotype female, 6 mm, dissected, 3 slides, AM P.100648; paratypes 9 specimens (6 gravid females, 1 male, 2 juveniles), AM P.100649. Paratypes SEM stubs: ZMH-K 45996 (stub 6); ZMH-K 45997 (stub 3 edge); Bicheno, Tasmania, Australia, 41°52 ’28” S, 148°18 ’13” E, from macroalga Durvillaea potatorum ( Labillardière) Areschoug, 1854, 20 September 2015, coll. M. Thiel.

Etymology.

Named for Ivan Hinojosa in recognition of his work with Crustacea and his involvement in the fieldwork which collected this species.

Type locality.

Bicheno, Tasmania, Australia.

Description.

Body shape subcylindrical, head rounded. Cephalic sinus absent. Eyes oval.

Pereonite 1 ventral margin with collar. Coxae 1-5 small and discontiguous. Antennae 1 same length as antenna 2; flagellum with 6 articles. Antenna 2 flagellum with 5 articles. Lower lip inner and outer lobes rounded; inner lobes apically setose. Mandible lacking palp; left incisor with 4 teeth, lacinia mobilis weakly developed; right mandible incisor with 6 teeth, 25% larger than left mandible. Maxilla 1 lacking palp; inner plate slender,

bearing 1 stout seta; outer plate with 7 setal teeth. Maxilliped inner plate long, subequal in length to outer plate, reaching end of palp article 2, with 5 apical robust setae; palp 4-articulate; article 4 blunt.

Gnathopod 1 coxa bilobate, twice as broad as deep; ischium two-thirds of basis length, length twice breadth; merus and carpus subequal, length twice breadth; propodus parachelate, length 3 times breadth, palm pollex length subequal to width, subtriangular, apically acute; dactylus unguiform and setose. Gnathopod 2 similar to gnathopod 1, with articles slightly greater in length; coxa small, triangular, twice as broad as deep; merus smaller than carpus, length twice breadth, propodus parachelate, length 3 times breadth, palm pollex length subequal to width, subtriangular, apically acute; dactylus unguiform and setose.

Pereopods 3-4 similar; coxae subrectangular (irregular); merus expanded anterodistally, anterodistal lobe with small slender setae. Pereopods 5-7 increasing in length. Pereopod 5 basis subrectangular, posterior margin expanded, evenly convex; merus and carpus with posterior distal lobe well developed with small slender setae; dactylus unguiform. Pereopod 6 basis as wide as long, posterior margin expanded subquadrate; merus and carpus with posterior distal lobe well developed with small slender setae; dactylus unguiform. Pereopods 7 length twice the depth of pereonite 7; basis rounded, posterior margin convex, anterodistal lobe reaching merus; merus and carpus with posterior distal lobe well developed with small slender setae; dactylus unguiform. Pleopods 1-3 biramus.

Epimeral plates 1-3 rectangular. Epimeron 3 posterior margin pectinate, corner produced rounded. Urosomite 1 twice length of fused urosomites 2 and 3, urosomite 1 with pair of dorsally rounded carinae. Urosomite 3 posterior margin between uropod 2-3 produced acute to subacute. Uropod 1 peduncle same length than outer ramus; outer ramus about same length of inner ramus. Uropod 2 peduncle longer than outer ramus; outer ramus about 40% of inner ramus. Uropod 3 rami absent, subquadrate, with row of apical setae. Telson fleshy, deeply cleft, subquadrate; each lobe with feathered setae.

Remarks.

Bircenna hinojosai sp. nov. has a pair of dorsally rounded carina on the urosomite 1 and the irregular geometric shape of the telson (Fig. 3). These two characters are presently unique to B. hinojosai sp. nov. and thus separate it from all other known Eophliantidae . The subquadrate to triangular coxa 2 to 4 in B. hinojosai sp. nov. is similar to B. thieli sp. nov and B. macayi Lörz et al., 2010.

See also remarks for B. thieli sp. nov.