Bennelongia bidgelangensis, 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 : 38-42

Bennelongia bidgelangensis sp. nov.

( Figs 19 , 20 )

Etymology

The species is named after it type locality, Bidgelang Pool on Callytharra Springs Station in the Gascoyne, WA.

Diagnosis

Cp with pronounced anterior rostrum, posteriorly bluntly pointed; highly arched in right lateral view, LV overlapping RV on all sides. LV with relatively rounded anteroventral beak, rounded dorsal margin and large postero-ventral flange. RV in lateral view highly arched, with highest point of dorsal margin at about 1/3 of the total length. Lapel on RV broad, dorsally slightly sloping towards selvage. Hemipenis with ms with straight distal margin, ventrally produced as a pointed lobe, dorsally slightly protruding main peniferum as a bluntly pointed lobe; ls asymmetrical, in both hemipenes with straight distal margin and distally with blunt tip, but in one hemipenis with additional elongated thumb-like expansion; tips of ls and ms almost touching, ls very slightly longer than ventral lobe of ms; hallway perniferum with additional small internal lobe. Rpp with distal segment elongated and with narrow base. Lpp with proximal segment with broad, rectangular apical outgrowth; distal segment sickle-shaped, elongated, as long as first segment, and with almost parallel margins, except for distal part.

Measurements (all measurements in µm)

Male: RV: L = 1700-1780; H = 952-1030. LV: L = 1890; H = 1040-1110. Cp: L = 1920; W: 1030. Female: RV: L = 1950; H = 1170. LV: L = 2130; H = 1260. Cp: L = 2030-2090; H = 1230; W = 1130- 1210.

Type locality

Bidgelang Pool, Callytharra Springs Station, Gascoyne (WA), approximate coordinates: 24º 34’ 32”S 115º 36’ 01”E. All material collected by SH on 25 Aug. 1994 (OSTR14D).

Type material

Holotype

Male ( WAM.C49412 ), with soft parts dissected in a sealed slide, valves stored dry in a micropalaeontological slide.

Allotype

LV and RV of a female ( WAM.C49413) stored dry in a micropalaeontological slide.

Paratypes

Three males dissected and stored as the holotype ( WAM.C49414, WAM.C49417, OC.3320); one male ( WAM.C49415A) and three females ( WAM.C49415B-D) carapaces stored dry in a micropalaeontological slide, RV +LV of one male ( WAM.C49416).

Several specimens in EtOH ( WAM.C49418).

Other material investigated

The species is known from its type locality only.

Differential diagnosis

The species belongs to the B. australis group because of the generally large size (L> 1500 µm), the presence of a lapel on the RV and of a strong anterior rostrum in dorsal view. It can be distinguished from the other species in this lineage by the highly arched aspect of carapace and valves, the strongly produced postero-ventral flange on the LV (unique character for this species in the B. australis lineage), the broad and elongated lapel on the RV, dorsally sloping towards the selvage, the narrow second segment of the Rpp, and the fact that the tips of ls and ms of the hemipenes are almost touching each other.

Additional description

Valves in lateral view ( Figure 19 A-D) with middle part of dorsal margin almost straight, LV overlapping RV on all sides ( Figure 19K ), greatest height situated posteriorly from the middle; in dorsal and ventral views ( Figure 19 E-H) with greatest width in the middle of the carapace; anterior rostrum well-developed, posterior side bluntly pointed, LV dorsally ridge-like; external surface weakly pitted and set with short setae.

LV ( Figure 19A, C ) in inner view with slightly rounded dorsal margin, greatest height situated in the middle; antero-ventral beak-like expansion moderate and rounded; ventral margin slightly sinuous in the middle; postero-ventral flange strongly produced.

RV ( Figure 19B, D ) in inner view with greatest height situated at about 1/3 of total length, dorsal margin rounded; posterior selvage not sub-marginal, well inwardly displaced, posterior inner list merging with posterior selvage below half of the height of the valve; remnant of valve margin visible between lapel and valve margin; antero-ventral inner list running to about 1/4 of length of the lapel; selvage at height of lapel expanded, striate; lapel broad, dorsally slightly sloping towards selvage, slightly striate ( Figure 19I, J ).

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

Rpp ( Figure 20A, E ) with first segment c. 1.5 times as long as wide, subapically with one long and basally stout, and one very short sensory organ; second palp segment elongate and with narrow base, with straight distal margin; apically with one small sensory organ.

Lpp ( Figure 20C, D ) with first segment elongated, length c. 1.5 x central width as central width, subapically with one long, stout sensory organ; apically with broad, rectangular outgrowth, a small sensory organ at the base of this lobe; second palp segment nearly straight, sickle-shaped and relatively elongated, as long as first segment; distal part of this segment straight and with nearly parallel margins.

Hemipenes ( Figure 20B ) asymmetrical, with tips of ls and ms almost touching, ls and ms almost equally long; ventral part of ms produced into a bluntly pointed lobe, dorsally also extending beyond peniferum with a rounded lobe; ls almost rectangular, distal margin almost straight in both hemipenes, ventrally bluntly pointed in one hemipenis, with elongated thumb-like expansion in the other.

Ecology and distribution

The species is known from its type locality only, a permanent river pool along the mostly dry Wooramel River. Water conductivity was 106 µS cm-1 and pH 7.7.

Figures

Fig. 19. Bennelongia bidgelangensis sp. nov. (all from Bidgelang Pool, type locality). A. LVi (allotype ♀, WAM.C49413). B. RVi (♀, Idem). C. LVi (holotype ♂, WAM.C49412). D. RVi (♂, Idem). E. Cp dorsal (♀, WAM.C49415B). F. Cp ventral (♀, WAM.C49415C). G. Cp ventral (♂, WAM.C49415A). H. Cp dorsal (♂, Idem). I. RVi (detail anteriorly, holotype ♂, WAM.C49412). J. RVi (detail anteriorly, tilted, ♂, Idem). K. Cp RL (♀, WAM.C49415D). Scales: A-H, K = 500 µm; I, J = 200 µm.

Fig. 20. Bennelongia bidgelangensis sp. nov. (A-C = holotype ♂, WAM.C49412; D-E = WAM.C49414). A. Right prehensile palp. B. Outline of hemipenes. C. Left prehensile palp. D. Left prehensile palp. E. Right prehensile palp. Scales: B = 232 µm; A, C-E = 92 µm.