Brevisomabathynella jundeeensis, 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 : 1022-1030

Brevisomabathynella jundeeensis sp. nov.

( Figures 19–22 )

Material examined

Holotype (adult male), allotype (adult female), paratypes (five adult males and five adult females). Holotype dissected on five slides ( WAM C 40085) . Allotype dissected on six slides, same data as for holotype, except BES 6471 (26°21′22″ S, 120°38′56″ E) ( WAM C 40086) . Paratypes: two adult males and one adult female each dissected on five slides, same data as for allotype ( WAM C 40281, C 40888, C 40889) .

Type locality

Australia, Western Australia, Gascoyne, Jundee Station, JSP 10, South Hill Well BF, Jundee Mine (26°16′58″ S, 120°40′33″ E), BES 6580, 11 May 2001, leg. W.F. Humphreys C.H.S. Watts and S.J.B. Cooper.

Other locality

One adult male and one adult female, each dissected on five slides ( WAM C 40282, C 40890), Jundee Station, bore next to “sacred” well Jundee soak (26°21′22″ S, 120°38′56″ E), BES 6474, 10 May 2001, leg. W.F. Humphreys, C.H.S. Watts and S.J.B. Cooper ; two females, one dissected on five slides, one as a whole specimen in a slide ( WAM C 40283, C 40891), Jundee Station , JSP1 South Hill Well BF, Jundee Mine (26°16′58″ S, 120°40′33″ E), BES 6578(6579), 11 May 2001, leg. W.F. Humphreys, C.H.S. Watts and S.J.B. Cooper ; one male and one female, each as a whole specimen on separate slides ( WAM C 40284, C 40892), Jundee Station , OB behind JSP12 South Hill Well BF, Jundee Mine (26°17′14″ S, 120°40′16″ E), BES 6587, 11 May 2001, leg. W.F. Humphreys, C.H.S. Watts and S.J.B. Cooper ; one male, as a whole specimen on a slide ( WAM C 40285), Jundee Station . JE150 South Hill Well BF, Jundee Mine (26°16′58″ S, 120°40′33″ E), BES 6598, 11 May 2001, leg. W.F. Humphreys, C.H.S. Watts and S.J.B. Cooper.

Description of adult male (holotype)

Body. Length 3.42 mm ( Figure 19 ). Head as long as anterior three thoracic segments 1–3 combined, approximately 10 times as long as wide

Antennule ( Figure 20A,B ). Seven-segmented. First segment with one seta on inner margin, with three 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 four (left) or six (right) simple setae on inner margin ( Figure 20B ). Third segment with three lateral setae including one plumose seta and 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 four setae on inner margin and one dorsal seta. 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 20C ). Five-segmented, as long as antennular segments 1–3 combined. Fourth segment slightly shorter than fifth segment. Setal formula: 0+0/ 0+0/1+1/1+1/3(1). Plumose seta of distal segment shorter than longest simple seta.

Labrum ( Figure 20D ). Flat, with total 24 teeth. Twelve median teeth of more or less similar size flanked by six teeth decreasing in size laterally. Ventral surface with numerous combs of ctenidia and teats.

Mandible ( Figure 20E ). Incisor process of six teeth. Tooth of ventral edge triangular. Spine row consisting of 12 spines. Palp of one segment, with one apical seta.

Maxillule ( Figure 20F ). Two-segmented. Proximal segment with four setae on inner margin. Distal segment with two terminal spines, with four spines with denticles and one tiny proximal spine on inner edge, and with three simple setae on outer margin.

Maxilla ( Figure 20G ). Four-segmented, setal formula 5-5-11-9.

Thoracopods I–VII ( Figures 20H , 21 A–C, 22A–C). Thoracopods I–IV increasing in size posteriorly. Thoracopods IV–VII similar in size. Thoracopods I–VII each with one epipod on protopod, and with one seta on basipod. Number of exopodal segments of thoracopods I–VII: 5-7-8-9-9-9-8. Endopod of thoracopods I–VII four-segmented, setal formulae:

Th. I 3+1/5+1/2+1/4(2)

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

Th. IV 2+1/6+1/2+1/5(3)

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

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

Th. VII 1+1/4+1/3+1/4(2)

Thoracopod VIII ( Figure 20I,J ). More or less rectangular in frontal view, twice as long as wide. Protopod massive, with prominent penial region with terminal opening. Epipod large, conical, distal part barely reaching penial region of protopod. Basipod without setae, inner margin of basipod drawn out into projection. Exopod one-third size of basipod, triangular, bearing two subterminal setae. Endopod as long as exopod, with two terminal setae.

First pleopod. Absent.

Uropod ( Figure 21D ). Fifteen spines on inner margin of sympod. Exopod 70% as long as sympod, with 11 setae on outer and terminal margin, without basiventral setae. Endopod 41% 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 additional spines on inner margin. Terminal and subterminal spines similar in size. Three inner-marginal spines spike-like, twothirds as long as terminal spines and thin.

Pleotelson ( Figure 21D,E ). One seta near base of each furcal ramus on both sides. Anal operculum concave.

Furcal rami ( Figure 21D,E ). Twice as long as width, with two large terminal spines, and 12 spines on inner margin, and with two dorsal setae.

Description of adult female (allotype)

Body. Length 3.33 mm. Identical to male except for following characters.

Antennule. Second segment with six setae on inner margin, no difference between right and left antennules.

Mandible. Spine row consisting of nine spines.

Maxilla. Setal formula: 4-5-11-9

Thoracopods I–VII. Number of exopodal segments of thoracopods I–VII: 5-6-7-8-8- 8-7. Setal formulae of endopods:

Th. I 3+1/4+1/2+1/4(2)

Th. II, III 2+1/4+1/1+1/4(2)

Th. IV–VI 1+1/4+1/1+1/4(2)

Th. VII 1+1/3+1/1+1/4(2)

Thoracopod VIII ( Figure 20K ). Conical, half as long as endopod of male thoracopod VIII, with one terminal tooth.

Uropod. Sympod with 14 spines. Exopod with 12 setae.

Furcal rami. Eleven spines on inner margin.

Intraspecific variation

Range of body length: male 3.07–3.42 mm; female 2.89–3.33 mm. Variation in number of setae, spines or segments as listed in Table 4.

Etymology

The specific name refers to Jundee Pastoral Station.

Figures

Figure 19. General habitus of Brevisomabathynella jundeeensis sp. nov. (Ƌ, holotype). Scale bar 1 mm.

Figure 20. Brevisomabathynella jundeeensis sp. nov. (Ƌ, holotype; ♀, allotype): (A) left antennule Ƌ (dorsal); (B) second segment of right antennule Ƌ (dorsal); (C) left antennla Ƌ (dorsal); (D) labrum Ƌ (ventral); (E) left mandible Ƌ (ventral); (F) left maxillule I Ƌ (ventral); (G) right maxilla (dorsal); (H) right thoracopod VII Ƌ (frontal); (I) left thoracopod VIII Ƌ (inner lateral); (J) right thoracopod VIII Ƌ (frontal); (K) right and left thoracopods VIII ♀. Scale bars 0.1 mm.

Figure 21. Brevisomabathynella jundeeensis sp. nov. (Ƌ, holotype): (A) right thoracopod I (frontal); (B) right thoracopod II (frontal); (C) left thoracopod III (frontal); (D) pleotelson, furcal rami and uropod (lateral); (E) pleotelson and furcal rami (dorsal). Scale bars 0.1 mm.

Figure 22. Brevisomabathynella jundeeensis sp. nov. (Ƌ, holotype): (A) right thoracopod IV (frontal); (B) right thoracopod V (frontal); (C) left thoracopod VI (frontal). Scale bar 0.1 mm.