Bilocypris fortescuensis, Halse & Martens, 2019

Halse, Stuart A. & Martens, Koen, 2019, Four new genera and five new species of ‘ Heterocypris’ from Western Australia (Crustacea, Ostracoda, Cyprinotinae), European Journal of Taxonomy 493, pp. 1-35 : 18-22

Bilocypris fortescuensis gen. et sp. nov.

urn:lsid:zoobank.org:act:9354F295-A5CF-4DB4-A1B1-9DA925F677E9

Figs 8–9

Diagnosis

Valves arched, greatest height situated in middle. RV with anterior and posterior marginal selvage. Large marginal tubercles present along anterior, postero-ventral and posterior margins. Lpp with elongated first and second segment; first segment with sub-parallel margins; second segment sickle-shaped and with flagellum-like distal part. Hemipenis with lobe ls spatulate rather than boot-shaped, and with distal margin almost straight; lobe ms bilobed; distal part of bc long, stout and pointed.

Etymology

Named after the type locality, Fortescue Marsh, Pilbara, Western Australia.

Measurements

See Table 1.

Type locality

Fortescue Marsh, Pilbara, Western Australia. Approximate coordinates: 22°30′48″ S, 119°46′41″ E. Collected by Jane McRae and Adrian Pinder, 16 Aug. 2003 (sample PSW002). Subsequent collections made by S. Halse, I. Schön and K. Martens, 24 Apr. 2006 (sample KIES11).

Material examined

Holotype

AUSTRALIA • ♂; Western Australia, Pilbara, Fortescue Marsh ; 22°30′48″ S, 119°46′41″ E [approximate coordinates]; 16 Aug. 2003; Jane McRae and Adrian Pinder leg.; sample PSW002; dissected, with soft parts stored in glycerine on a sealed slide and valves stored dry in a micropalaeontological slide; WAM 67205.

Allotype

AUSTRALIA • ♀; same collection data as for holotype; dissected and stored as the holotype; WAM 67206.

Paratypes

AUSTRALIA • 1 ♂; same collection data as for holotype; dissected and stored as the holotype; WAM 67207 • 2 female carapaces; same collection data as for holotype; used for SEM and stored in a micropalaeontological slide; WAM 67208 to 67209 • 1 ♂, 3 ♀♀; same collection data as for holotype; in EtOH as bulk paratypes; WAM 67211 • 1 ♂; same locality as for holotype; 24 Apr. 2006; S. Halse, I. Schön and K. Martens leg.; sample KIES11 ; with valves stored dry in micropalaeontological slide and with soft body successfully used for DNA extraction; RBINS INV 138036 • 1 ♀; same collection data as for preceding; used and stored as preceding; WAM 67214 • 2 ♂♂; same collection data as for preceding; carapaces used for SEM and stored dry in micropalaeontological slides; WAM 67212 to 67213 • 3 ♀♀; same collection data as for preceding; used and stored as preceding; WAM 67215 to 67216, RBINS INV 138037 . The bulk sample of sample KIES11 was lost .

Description

Male

RV ( Fig. 8B ). Arched, greatest height situated in middle; anterior margin rounded, posterior margin nearly straight, ventral margin weakly sinuous in middle. With both anterior and posteroventral submarginal selvages, anterior and posteroventral margins set with medium-sized marginal tubercles. Anterior calcified inner lamella relatively wide, posterior lamella narrow; both lamellae without inner lists.

LV ( Fig. 8A ). Generally with shape as in RV, slightly larger. Anterior calcified inner lamella slightly wider than in RV, blunt anterior inner list running parallel to most of valve margin, posteriorly with blunt inner list in top part of calcified inner lamella.

CARAPACE. In dorsal ( Fig. 8J, M ) and ventral views (see Fig. 8C, E , of female carapace) with weak anterior rostrum; greatest width situated in middle. In lateral view ( Fig. 8H ) with anterior LV/RV overlap prominent (illustrated for females in Fig. 8G, I ).

PREHENSILE PALPS ON T1. Asymmetrical, chaetotaxy of endopodite as typical for family (not shown). Rpp ( Fig. 9C ) with second segment as in previous species, also without the additional protrusion on dorso-proximal corner. First segment expanding distally, with two ventro-distal lobes, each supporting a sensory organ. Lpp ( Fig. 9B ) with nearly rectangular first segment, ventro-distal lobes narrow and bluntly pointed; second segment sickle-shape and narrow, with long distal, flagellum-like expansion.

ZENKER ORGAN. As typical of family, i.e., ca 3–5 × as long as wide and with numerous spinous whorls.

HEMIPENIS ( Fig. 9A ). With ls spatulate, with distal margin nearly straight; ms bilobed as a result of distal indentation, a small additional rounded ‘lobe’ present on ventral side of ms; distal part of internal bc stout and elongated, with pointed tip.

CAUDAL RAMUS ( Fig. 9E ). Curved; its attachment ( Fig. 9D ) uniramous.

Female VALVES ( Fig. 8D–E ). With shape similar to that of male. Valve margin anatomy as in male, except for more inwardly displaced posteroventral selvage in LV.

CARAPACE. In ventral ( Fig. 8K ) and dorsal ( Fig. 8L ) views as in male.

A1, Md, Mx1, T2, T3 and attachment of CR as in male.

A2 (not shown). With distal chaetotaxy showing sexual dimorphism as typical of family. T1 (not shown). With palp not segmented, relatively elongated.

GENITAL LOBES. Large and with rounded distal and sub-parallel lateral margin.

Differential diagnosis

Bilocypris fortescuensis gen. et sp. nov. is closely related to B. mandoraensis gen. et sp. nov. (see below), but can be distinguished from it by its smaller size, less pronounced bilobed nature of the lobe ms of the hemipenis, the shape of lobe ls (spatulate in B. fortescuensis gen. et sp. nov., pointed boot-shaped in B. mandoraensis gen. et sp. nov.) and the shape of the second segment of the Rpp (robust and subtriangular in B. fortescuensis gen. et sp. nov., more elongated, with a skewed shape in B. mandoraensis gen. et sp. nov.).

Ecology and distribution

Bilocypris fortescuensis gen. et sp. nov. has been collected only from Fortescue Marsh, a very large mostly hyposaline playa in the central Pilbara region of Western Australia. The marsh floods every few years and holds water for up to six months. Bilocypris fortescuensis gen. et sp. nov. has been recorded at salinities of 3400 and 12 0 0 0 mg L-1 TDS ( Pinder et al. 2010).

Remarks

No male soft parts of the KIES11 material could be checked. However, the valve morphology is so similar, almost identical, to that of the PSW002 material collected at the same location three years earlier that the conspecificity of the animals in the two samples cannot be doubted.

There is a hint of a third lobe occurring ventrally on the ms but, because it is more of a ridge than a lobe we do not interpret it as homologous to full-sized third lobe observed in Trilocypris horwitzi gen. et sp. nov.

Figures

Fig. 8. Bilocypris fortescuensis gen. et sp. nov., Forstescue Marsh (type locality). A. LVi, ♂, holotype (WAM 67205). B. RVi, ♂, holotype (WAM 67205). C. CpV, detail anterior, ♀ (WAM 67216). D. LVi, ♀, allotype (WAM 67206). E. RVi, ♀, allotype (WAM 67206). F. RVi, ♀, detail central muscle scars, allotype (WAM 67206). G. CpRL, ♂ (WAM 67212). H. CpRL, ♀ (WAM 67215). I. CpRL, detail anterior, ♀ (WAM 67212). J. CpD, ♂ (WAM 67213). K. CpV, ♀ (WAM 67216). L. CpD, ♀ (RBINS INV 1380377). M. CpD, detail anterior, ♂ (WAM 67213). Scales: A–B, D–E, G–H, J–L = 1 mm; C, F, M = 200 µm; I = 300 µm.

Fig. 9. Bilocypris fortescuensis gen. et sp. nov., ♂, holotype (WAM 67205), from Forstescue Marsh (type locality, sample PSW002). A. Hp. B. Lpp. C. Rpp. D. CR attachment (note: the bifurcation at the left side is the basis of the actual CR). E. CR. Scale = 92 µm.