Bennelongia strellyensis, Martens & Schön, 2012

Martens, Koen, Halse, Stuart & Schön, Isa, 2012, Nine new species of Bennelongia De Deckker & McKenzie, 1981 (Crustacea, Ostracoda) from Western Australia, with the description of a new subfamily, European Journal of Taxonomy 8, pp. 1-56 : 42-46

Bennelongia strellyensis sp. nov.

( Figs 21 , 22 )

Bennelongia australis s.l. ( Brady, 1886) – Karanovic 2008: 282-286, figs 10-12.

Etymology

Named after the type locality, Strelley Station, Pilbara (WA).

Diagnosis

Cp with pronounced anterior rostrum, posteriorly bluntly pointed; rounded in right lateral view, LV overlapping RV on all sides, external valve surface centrally almost completely smooth and devoid of setae. LV with pronounced anteroventral beak, and highly arched, rounded dorsal margin. RV in lateral view rather elongated, with highest point of dorsal margin at about 1/3 of the total length; lapel on RV absent, but valves building a triangular bulbous expansion in the same location; anterior selvage with flange-like expansion and with additional inner submarginal list.

Hemipenis symmetrical, heavily sclerotized. ms forming a three-dimensional structure, embracing ls along three sides (proximal, ventral, distal). ls a large, slightly curved lobe, with almost parallel sides, distally bluntly pointed in ventral direction. About halfway the hemipenal body, one additional lobe present.

Rpp with distal segment short and rounded, with blunt tip bearing a sensory organ. Lpp with distal segment sickle-shaped, rounded and short.

Measurements (all measurements in µm)

Male: RV: L = 1710-1900; H = 1090-1130. LV: L = 790-2010; H = 1080-1220. Cp: L = 1860-1880; H = 1120; W = 1140-1150.

Female: RV: L = 1870; H = 1130. LV: L = 1980; H = 1200. Cp: L = 1880-2000; H = 1170; W: 1160-1230.

Type locality

Unnamed roadside pool on Strelley Station, Pilbara, WA (KIES3), approximate coordinates: 20º 31’ 24”S 119º 03’ 40”E. All material collected on 22 Apr. 2006 by the authors.

Type material

Holotype

Male ( WAM.C49419 ), with soft parts dissected in a sealed slide, valves stored dry in a micropalaeontological slide.

Allotype

LV and RV of a female ( WAM.C49420) stored dry in a micropalaeontological slide.

Paratypes

Three males ( WAM.C49421, 49422, OC.3321) dissected and stored as the holotype; three females ( WAM.C49423A-C) and two males ( WAM.C49424A,B) carapaces stored dry in a micropalaeontological slide; RV +LV of a male ( WAM.C49425).

Several juvenile specimens: RV +LV of males (A-1) ( WAM.C49426); 3 Cp of females (A-1) and 3 Cp of females (A-3) ( WAM.C49427AF).

Several specimens in EtOH ( WAM.C49428).

Other material investigated

Cooliarin Pool, Pilbara (WA), collected by Adrian Pinder on 10 Sep. 2004, approximate coordinates: 20º 30’ 20”S 118º 37’ 20”E ( PSW 033). Specimens from this locality: RV +LV of two females ( WAM. C49429, 49330).

Errawallana Spring, Pilbara (WA), collected by Adrian Pinder on 10 Sep. 2004, approximate coordinates: 21º 37’ 48”S 117º 46’ 14”E ( PSW 055). Specimens from this locality: a male, dissected and stored as the holotype ( WAM.C49431).

Differential diagnosis

Bennelongia strellyensis sp. nov. belongs to the B. pinpi lineage, and therefore differs from all other species in the genus not belonging to this lineage by a combination of the following characters: large species, with well-developed anterior rostrum and bluntly pointed posterior end in dorsal view; RV without antero-ventral lapel, but with bulbous expansion of the valve there; antero-ventral selvage with an additional submarginal inner list. LV with antero-ventral beak well-developed. Hemipenis stout and well-sclerotized; ms a ventral, 3-dimensional structure enveloping the ls. Rpp with short and rounded second segment. Lpp with second segment sickle-shaped and short.

Within this lineage, B. strellyensis sp. nov. differs from B. pinpi by the length of the antero-ventral beak in the LV (longer in B. pinpi ) and by the shape of the valves in lateral view (more highly arched in B. pinpi ). The differences between B. strellyensis sp. nov. and B. kimberleyensis sp. nov. will be outlined below.

Additional description

Valves in lateral view ( Figures 21 A-D) with rounded dorsal margin, LV overlapping RV on all sides ( Figures 21K, L ), greatest height in the middle; in dorsal and ventral views ( Figures 21 E-H) with greatest width in the middle of the carapace; anterior rostrum well-developed, posterior side bluntly pointed, LV. Dorsally only anteriorly ridge-like; external valve surface centrally almost completely smooth and devoid of setae.

LV ( Figure 21A, C ) in inner view with rounded dorsal margin, greatest height situated in front of the middle; antero-ventral beak-like expansion large.

RV ( Figure 21B, D ) in inner view with greatest height situated well in front of the middle, dorsal margin rounded; posterior selvage submarginal; lapel on RV absent, but valves building a triangular bulbous expansion in the same location ( Figure 21I, J ); anterior selvage with flange-like expansion and with additional inner submarginal list dorsally merging with selvage.

Most appendages as typical of the genus and without special features.

Rpp ( Figures 22 B , 24D ) with first segment c. twice as long as central width, subapically with one longer (but less so than in species of the previous lineage), and one short sensory organ; second palp segment triangular, broad, without clear ventro-apical corner and rounded distal margin; apically with one small sensory organ.

Lpp ( Figure 22C, D ) with first segment elongated, more than 2.5 x as long as central width, subapically with one large and stout sensory organ, apically with rounded outgrowth, without sensory organ; second palp segment sickle-shaped short, and asymmetrically curved over c. 180º, distally with a small sensory organ.

Hemipenes ( Figure 22A ) symmetrical, ls protruding well beyond ms, distally bluntly pointed towards the ventral side, proximally with nearly parallel sides; ms actually consisting of three lobes: distal part of ms (ms1) produced into a three-dimensional lobe, embracing the ls on proximal and distal sides (this not visible in drawing, which is made of a flattened hemipenis in a slide) and with a small additional dorsal lobe; ms2 with distal margin nearly straight, ms3 straight and incomplete. (Remark: ms 2 in some populations weakly developed and almost invisible – see below).

Ecology and distribution

The species is common in moderately turbid claypans and roadside pools, and in clear water springs, in the Pilbara where it may occur in high densities. The species has been recorded in waters with conductivity 82-1391 µS cm-1 and pH 7.5-8.9.

Remarks

The present species closely resembles B. kimberleyensis sp. nov. described below, as was the case of the 5 sibling species in the previous B. australis lineage. The specific status of both new taxa was nevertheless confirmed by molecular methods (see results above), where all the Pilbara and all the Kimberley specimens clustered together in two distinct groups.

Figures

Fig. 21. Bennelongia strelleyensis sp. nov. (all from Strelley station, Pilbara, type locality). A. LVi (allotype ♀, WAM.C49420). B. RVi (♀, Idem). C. LVi (♂, WAM.C49421). D. RVi (♂, Idem). E. Cp dorsal (♀, WAM.C49423A). F. Cp ventral (♀, WAM.C49423B). G. Cp ventral (♂, WAM. C49424B). H. Cp dorsal (♂, WAM.C49424A). I. RVi (detail anteriorly, allotype ♀, WAM.C49420). J. RVi (detail anteriorly, ♀, Idem). K. CpRL (♀, WAM.C49423C). L. CpRL (♂, WAM.C49424A). Scales: A-H, K = 1000 µm; L = 500 µm; I-J = 200 µm.

Fig. 22. Bennelongia strellyensis sp. nov. (all from Strelley Station, Pilbara, type locality; ♂; A-C = holotype ♂, WAM.C49419; D=OC.3321). A. Hemipenis outline. B. Right prehensile palp. C. Left prehensile palp. D. Left prehensile palp. Scales: A = 232 µm; B-D = 92 µm.

Fig. 24. A-C, E, F. Bennelongia kimberleyensis sp. nov. (♂, OC.3323, Parry’s Lagoon, Kimberley); D. B. strellyensis sp. nov. (♂, WAM.C49421, Strelley Station, Pilbara). A. Right prehensile palp. B. Left prehensile palp. C. Hemipenis outline. E. T2. F. A1, without chaetotaxy, showing strongly sclerified dorsal margins of segments. D. Right prehensile palp. Scales: C, E, F = 232 µm; A, B, D = 92 µm.