Agnathia, Staples, 2021

Staples, D. A., 2021, Diagnosis ofthe new genusAgnathia (Pycnogonida, Callipallenidae) and description of two new species from southern Australia, Zootaxa 4950 (3), pp. 487-500 : 488-489

Genus Agnathia gen. nov.

Diagnosis. Callipallenidae . Trunk, moderately slender, smooth, lateral processes about as long as wide, separated by less than their own diameter, or segments 3 and 4 in contact; neck short, constricted at base, swollen distally with strong dorsal lobes at bases of chelifores. Ocular tubercle about as tall as wide, placed about level with the anterior margin of first lateral processes, four eyes. Proboscis narrowing seamlessly to distal tubular part with terminal field of simple, short, tangled setae, sclerotized jaws absent, three lips reflexing. Palps absent. Chelifore scape one-segmented, directed downwards, scape sexually dimorphic, female with conspicuous proximal ventral constriction; chela mostly anaxial, equally developed in both sexes, moveable finger either upper-most or facing oral surface, fixed finger rounded in cross-section and at tip, without sclerotized cutting edge, single proximal tooth present; inner surface of palm swollen, bearing either single strong spine or prominent spine-bearing process. Oviger six-segmented in the male only, or ten-segmented both sexes, bases in contact with first lateral processes, female segment 4 longest, male segment 5 longest with distal apophysis, ten-segmented oviger with strigilis, spines present in female only, simple, strongly curved, female terminal claw long, denticulate, male claw short, non-denticulate, claw absent in six-segmented oviger. Anal tubercle short, slightly inclined, not segmented or articulated at base. Legs slender, surface highly irregular, tarsus short, auxiliary claws absent. Genital pores, female large, conspicuous, male tiny. Cement glands not recorded.

Type species. Agnathia aria sp. nov.

Etymology. Agnathos, having a mouth without jaws. Gk. ‘ a ’ without, ‘ gnathos ’ jaw. Gender is feminine.

Distribution. Recorded distribution extends from the Investigator Group of islands, eastern Great Australian Bight to Gabo Island eastern Victoria and Bass Strait islands, Tasmania. Depth range 0.5 m to 21 m. All specimens were collected from shallow, temperate waters, mostly from algal samples. Association with a specific host substrate is unknown.