Hexabathynella virginiae, Cho & Schminke, 2006

Cho, Joo-Lae & Schminke, Horst Kurt, 2006, A phylogenetic review of the genus Hexabathynella Schminke, 1972 (Crustacea, Malacostraca, Bathynellacea): with a description of four new species, Zoological Journal of the Linnean Society 147 (1), pp. 71-96 : 83

publication ID	https://doi.org/ 10.1111/j.1096-3642.2006.00215.x
DOI	https://doi.org/10.5281/zenodo.10544823
persistent identifier	https://treatment.plazi.org/id/03E6686E-446F-FF87-25A6-2DE4FE5BB209
treatment provided by	Felipe
scientific name	Hexabathynella virginiae
status	sp. nov.

Treatment

HEXABATHYNELLA VIRGINIAE SP. NOV.

Diagnosis: Parabathynellid of middle size (1.30– 1.45 mm). Antennal organ protruded and bearing two similar whip-shaped setae. Pleotelson with one seta. Uropodal exopod bearing three setae.

Holotype ♀, USA, Hughes River, Culpeper, Madison , Virginia. Gritbank on right shore of the river located 50 m over the bridge of street 231. Pit 60 cm, temperature 20°C, coll. 22 August 1973 by W. Noodt, coll. Western Australian Museum , Perth ( WAM C 34438) . Allotype ♂ ( WAM C 34439), same local data as for holotype . Paratype two ♂♂ and four ♀♀ ( WAM C 34440), same local data as for holotype .

Etymology: The species is named after the state of Virginia, USA, where it is collected.

Description of the female (holotype): Body length 1.45 mm, approximately 12 times as long as wide. Head as long as length of one to three segments, 40% longer than width.

Antennule ( Fig. 9A View Figure 9 ) six-segmented. First segment with one seta on inner distal margin, one simple dorsal seta, and two lateral plumose setae. Second segment with one group of four plumose setae, and one simple seta on inner distal margin. Third segment with one simple seta on inner distal margin, three lateral setae and one ventral seta. Peduncle on third segment with three simple setae. Fourth segment with one stub seta on dorsal margin, and with three plumose setae. Fifth segment with two setae on inner margin, three aesthetascs and one simple dorsal seta. Sixth segment with four terminal setae and three subterminal aesthetascs.

Antenna ( Fig. 9D View Figure 9 ) five-segmented, 40% as long as antennule, setal formula: 0/0+0/0+0/1+0/3(1).

Labrum ( Fig. 9E View Figure 9 ) flat, with eight main teeth flanked by one smaller lateral tooth on both sides.

Mandible ( Fig. 9F View Figure 9 ) with incisor process ( Fig. 9G View Figure 9 ) of five teeth. Tooth of ventral edge tiny, triangular. Spine row consisting of five spines. Palp of one segment with one apical seta being three times as long as palp.

Maxillule ( Fig. 9H View Figure 9 ) two-segmented. Proximal segment with four setae on inner distal margin. Distal segment with three terminal claws, two claws on inner edge, and three simple setae on outer distal margin.

Maxilla ( Fig. 9I View Figure 9 ) three-segmented, setal formula 2-4-14.

Thoracopods I–IV increasing in length, bearing one basal seta. Thoracopod I ( Fig. 9J View Figure 9 ) without epipodite. Thoracopod II–VI ( Fig. 10A–D View Figure 10 ) with one epipodite. Exopod of thoracopods I one-segmented, with one terminal seta. Exopod of thoracopod II–VI twosegmented, with two setae on proximal segment, and one terminal seta on distal segment. Endopod of thoracopods I–VI four-segmented, setal formulae: thoracopod I 1+0/0+1/1+0/2(1), thoracopods II–VI 0+0/0+1/0+1/1(0).

Thoracopod VIII tiny and sharply pointed.

Pleopod in form of seta.

Uropod ( Fig. 10E, F View Figure 10 ) bearing four spines on inner distal margin of sympod. Distal spine 1.5 times as long as proximal spines. Endopod 50% as long as sympod, drawn out distally in slightly curved spur, with one plumose seta and two simple setae at base of spur. Exopod as long as endopod, with two terminal setae and a dorsal subterminal seta. Inner terminal seta one third as long and thicker than outer seta. Dorsal subterminal seta shorter than inner terminal one and weak.

Pleotelson ( Fig. 10E, F View Figure 10 ) with a seta. Anal operculum projected.

Furcal rami ( Fig. 10E, F View Figure 10 ) as long as wide, with three spines and two dorsal setae.

Description of the male (allotype): The male differs from the female in the second antennular segment and thoracopod VIII.

Second antennular segment ( Fig. 9C View Figure 9 ) with one group of four plumose setae and antennal organ on inner distal margin. Antennal organ ( Fig. 9B View Figure 9 ) represented by a prominent protrusion bearing two setae. Both setae similar in form, rolled up and whip-shaped.

Thoracopod VIII ( Fig. 9K, L View Figure 9 ) massive. Penial region three-lobed. Frontal lobe split into two parts. Middle lobe with four to five teeth. Inner lobe with seven teeth of circular arrangement. Epipodite present as a tiny triangle. Basis with a seta at base of endopod. Inner margin of basis drawn out in a chitinous projection. Exopod bearing two tiny setae. Endopod as long as basis, bearing a terminal seta and a subterminal seta. Terminal seta with somewhat thick base and shorter than subterminal one.