Trilocypris horwitzi, 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: 13-17
treatment provided by
gen. et sp. nov.
Trilocypris horwitzi gen. et sp. nov.
Valves higher in posterior half than anterior, but with greatest height situated in middle. RV with both anterior and posterior sub-marginal selvage, posterior one somewhat more inwardly displaced than anterior one; anterior and posteroventral margins set with medium-sized marginal tubercles. LV anteriorly with blunt inner list (more like an elevation), posteriorly with inner list in top part of calcified inner lamella. Carapace in dorsal view with anterior rostrum. Rpp without additional protrusion on sub-triangular second segment. Lpp with almost rectangular first segment, but with rounded expansion in distal part of ventral margin; second segment sickle-shaped and with long, thin apical flagellum. Hemipenis with lobe ls boot-shaped; lobe ms asymmetrically rounded; additional lobe os rounded and pustulose; distal part of bc small and sickle-shaped, distally pointed.
This new species is named in honour of Prof. Pierre Horwitz (Edith Cowan University, Perth, Australia), who collected the present material, in recognition of his outstanding contributions to Western Australian limnology.
See Table 1.
Type locality Lake Austin, Western Australia. Approximate coordinates: 27°37′24″ S, 117°54′48″ E. Collected by
P. Horwitz, 1 Oct. 1997.
AUSTRALIA • ♂; Western Australia, Lake Austin ; 27°37′24″ S, 117°54′48″ E [approximate coordinates]; 1 Oct. 1997; P. Horwitz leg.; with soft parts dissected in glycerine on a sealed slide and with valves stored dry in a micropalaeontological slide; WAM 67199 View Materials . GoogleMaps
AUSTRALIA • 1 ♂; same collection data as for holotype; dissected and stored as the holotype; WAM 67201 View Materials GoogleMaps • 3 female carapaces; same collection data as for holotype; used for SEM and stored in a micropalaeontological slide; RBINS INV 138035 View Materials , WAM 67202 View Materials to 67203 GoogleMaps • 4 ♀♀, 2 ♂♂; same collection data as for holotype; in EtOH as bulk paratypes; WAM 67204 View Materials GoogleMaps .
This species has recently been collected from a small number of salt lakes around the type locality. Some of these specimens show slight morphological differences from the specimens described here.
RV ( Fig. 6B View Fig. 6 ). With anterior margin rounded and with greatest height in middle; dorsal margin sloping in anterior third, then straight, posterior margin straight, then broadly rounded in ventral half, ventral margin slightly sinuous in middle. RV with both anterior and posteroventral sub-marginal selvages, posterior one somewhat more inwardly displaced than anterior one, anterior and posteroventral margins set with medium-sized marginal tubercles. Calcified inner lamellae narrow, more so posteriorly; both lamellae without inner lists.
LV ( Fig. 6A View Fig. 6 ). Generally with shape comparable to that of RV, slightly larger. In inner view, anterior calcified inner lamella slightly wider than in RV. Anteriorly with blunt inner list running parallel to most of valve margin, posteriorly with blunt inner list in top part of calcified inner lamella.
CARAPACE. In dorsal and ventral views ( Fig. 6 F, H–J View Fig. 6 ) with weak anterior rostrum; greatest width situated in middle. In lateral view with prominent anterior LV/RV overlap (illustrated for females in Fig. 6C View Fig. 6 ).
PREHENSILE PALPS ON T1. Asymmetrical, chaetotaxy of endopodite as typical for family (not shown). Rpp ( Fig. 7D View Fig. 7 ) with subtriangular second segment as in previous species, but without additional process on dorso-proximal corner. Lpp ( Fig. 7E View Fig. 7 ) with nearly rectangular first segment, except for rounded distal part of ventral margin. Second segment sickle-shaped and narrow, with 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. 7C View Fig. 7 ). With ls boot-shaped, with ventrally directed blunt point; ms evenly rounded, additional lobe os rounded and pustulose. Extremity of internal bc small and sickle-shaped, with pointed tip.
VALVES ( Fig. 6D View Fig. 6 ). With shape similar to that of male. Valve margin anatomy as in male.
CARAPACE ( Fig. 6G View Fig. 6 ). Somewhat wider than in male, but also with weak rostrum.
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.
As for genus. Specifically, the structure and shape of the three hemipenis lobes are, to the best of our knowledge, different from that in all other species in the Cyprinotinae .
Ecology and distribution
Trilocypris horwitzi gen. et sp. nov. is known only from Lake Austin, a large, shallow saline pan situated more than 400 km from the coast, and some smaller pans in its immediate vicinity. Trilocypris horwitzi gen. et sp. nov. was hatched from Lake Austin sediment and collected from the hatching aquaria at salinities between 0.3 and 67.1 mS cm-1 (approximately 200 and 45 0 0 0 mg L-1). At the time the sediment was collected, Lake Austin was flooded and water salinity in the lake and pans varied from 23 0 0 0 mg L-1 to supersaturation. Some additional individuals of Trilocypris horwitzi gen. et sp. nov. were collected, but the salinity where they occurred was not recorded.
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