Brevisomabathynella magna, Cho & Humphreys, 2010

Cho, Joo-Lae & Humphreys, W. F., 2010, Ten new species of the genus Brevisomabathynella Cho, Park and Ranga Reddy, 2006 (Malacostraca, Bathynellacea, Parabathynellidae) from Western Australia, Journal of Natural History 44 (17 - 18), pp. 993-1079 : 995-1000

publication ID	https://doi.org/ 10.1080/00222930903537066
persistent identifier	https://treatment.plazi.org/id/03D887F9-FFF5-FFF8-FE2E-FEB6B5B76FE7
treatment provided by	Carolina
scientific name	Brevisomabathynella magna
status	sp. nov.

Treatment

Brevisomabathynella magna sp. nov.

( Figures 1–4 View Figure 1 View Figure 2 View Figure 3 View Figure 4 )

Material examined

Holotype (adult male), allotype (adult female), paratypes (two adult males and three adult females). Holotype: dissected on five slides ( WAM C 40072) . Allotype dissected on five slides ( WAM C 40073). One male and one female paratype each dissected on five slides; one male and two female paratypes each as a whole specimen on separate slides ( WAM C 40074 – C 40078) .

Type locality

Australia, Western Australia, Nabberu Palaeodrainage, Cunyu Station Site 272 Sweetwaters-Well (25°36′38″ S, 120°22′21″ E), BES 8158, 23 August 2001, leg. W.F. Humphreys, T. Karanovic and J.M. Waldock GoogleMaps .

Description of adult male (holotype)

Body. Length 4.62 mm. Elongated and cylindrical, approximately 10 times as long as wide. Head as long as anterior three thoracic segments combined ( Figure 1A,B View Figure 1 ).

Antennule ( Figure 2A View Figure 2 ). Seven-segmented. First segment with one seta on inner margin, with four simple dorsal setae and with one dorsal, one ventromedial and two lateral plumose setae. Second segment with one group of four plumose setae and with seven simple setae on inner margin. Third segment with four outer lateral setae including one plumose seta and one medial simple seta, and with six setae on inner margin. Inner flagellum of third segment with three simple setae. Fourth segment with one stub seta and one plumose seta on dorsal margin, and with two stub setae and two plumose setae on outer distal apophysis. Fifth segment with five setae on inner margin and one dorsal seta, without aesthetasc. Sixth segment with four setae on inner margin and with dorsal group of two aesthetascs, one simple seta and one additional aesthetasc lateral to simple seta. Seventh segment with three subterminal aesthetascs and four simple setae.

Antenna ( Figure 2B View Figure 2 ). Five-segmented, as long as antennular segments 1–5 combined. Fourth segment over twice as long as fifth segment. Setal formula: 0+0/0+0/1+1/2+1/ 5(1). Plumose seta of distal segment shorter than longest simple seta.

Labrum ( Figure 2C View Figure 2 ). Flat with eight median teeth of more or less similar size flanked by five smaller teeth on each side. Ventral surface with numerous combs of ctenidia and teats.

Mandible ( Figure 2D View Figure 2 ). Incisor process of seven teeth. Tooth of ventral edge triangular. Spine row consisting of 13 spines. Palp of one segment, with two apical setae and one subterminal seta.

Maxillule ( Figure 2E View Figure 2 ). Two-segmented. Proximal segment with four setae on inner margin. Distal segment with two terminal spines, with five spines with denticles on inner edge, and with three simple setae on outer margin.

Maxilla ( Figure 2F View Figure 2 ). Four-segmented, setal formula 8-7-18-17.

Thoracopods I–VII ( Figures 2 View Figure 2 G–I, 3A, 4A–D). Thoracopods I–IV increasing in size posteriorly. Thoracopods IV–VII similar in size. Thoracopods I–VII each bearing one epipod on protopod. Basipod of thoracopod I with two setae, those of thoracopods II–VII with one seta. Number of exopodal segments of thoracopods I–VII: 5-8- 9-10-9,10-8-9. Endopod of thoracopods I–VII four-segmented, setal formulae:

Th. I 5+1/7+2/4+1/4(2)

Th. II 2+1/7+2/4,3+1/4(2),5(3)

Th. III 2,3+1/7,6+2/4,3+1/5(3), 4(2)

Th. IV 2+1/7+2/3+1/4(2)

Th. V 2+1/6+2/3+1/4(2)

Th. VI 2+1/6+2/4+1/4(2)

Th. VII 1+1/5+2/2+1/5(3)

Thoracopod VIII of male ( Figure 2J,K View Figure 2 ). More or less oval in lateral view, 1.2 times as long as wide. Protopod massive, with prominent penial region with terminal opening. Epipod large, triangular, distal part barely reaching penial region of protopod. Basipod without setae, inner margin of basipod drawn out into projection. Exopod onethird size of basipod, triangular, bearing two subterminal setae. Endopod as long as exopod, with two terminal setae.

First pleopod ( Figure 2M View Figure 2 ). In form of two stubs attached to each other basally. Each stub bearing two terminal setae.

Uropod ( Figure 3B,C View Figure 3 ). Twenty spines of similar size on inner margin of sympod. Exopod 35% as long as sympod, without basiventral setae, and with 11 setae on outer and terminal margin. Endopod 29% as long as sympod, with two dorsal plumose setae near base, with two terminal setae and one subterminal plumose seta on outer margin, and with one terminal, one subterminal and three inner-marginal spines. Terminal and subterminal spines similar in size. Three inner-marginal spines spike-like, as long as terminal spine but thinner.

Pleotelson ( Figure 3B,C View Figure 3 ). One seta near base of each furcal ramus on both sides. Anal operculum flat.

Furcal rami ( Figure 3B,C View Figure 3 ). Four times as long as wide, with two large terminal spines, and 18 spines on inner margin, and with two dorsal setae.

Description of adult female (allotype)

Body. Length 4.42 mm. Identical to male except for following characters.

Antennule. First segment with five simple dorsal setae. Second segment with 10 simple setae on inner margin. Third segment with seven setae on inner margin. Fifth segment with four setae on inner margin.

Antenna. Setal formula: 0+0/0+0/1+1/3+1/5(1).

Thoracopods I–VII. Number of exopodal segments of thoracopods I–VII: 7-9-10-10- 10-10-10. Setal formulae of endopods:

Th. I 5+1/8+2/4+1/4(2)

Th. II 2+1/7+2/4, 3+1/4(2),5(3)

Th. III, IV 2+1/7+2/4,3+1/4(2)

Th. V 2+1/7+2/2+1/4(2)

Th. VI 2+1/6+2/2+1/4(2)

Th. VII 1+1/5+2/1+1/4(2)

Thoracopod VIII ( Figure 3L View Figure 3 ). Conical, half as long as endopod of male thoracopod VIII, with one terminal tooth.

Uropod. Sympod with 21 spines.

Furcal rami. Eighteen spines on inner margin.

Intraspecific variation