Bennelongia cuensis, 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 : 33-38

Bennelongia cuensis sp. nov.

( Figs 17 D-H, 18)

Etymology

The species is named after a small outback town, Cue, near its type locality.

Diagnosis

Cp with pronounced anterior rostrum, posteriorly bluntly pointed; in right lateral view, LV overlapping RV on all sides, but with distinct overlap on the dorsal side. LV with relatively rounded anteroventral beak and almost straight dorsal margin. Lapel on RV broad, running parallel to selvage. Hemipenis with ms with straight and broad distal margin, ventrally produced as a long lobe, dorsally also protruding main peniferum as a rounded lobe; ls asymmetrical, in both hemipenes with rounded distal margin and distally with blunt tip, but in one hemipenis without and in the other hemipenis with additional (and unusually elongated) thumb-like expansion; tips of ls and ms well-separated, ls significantly longer than ventral lobe of ms. Rpp with distal segment triangular, relatively elongated and with narrow base. Lpp with proximal segment with small, triangular 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 = 1810; H = 1040. LV: L = 1930; H = 1130. Cp: L = 1820-1960. H = 1090. W = 1040-1080. Female: Cp: L = 2170-2230; H = 1360; H = 1180-1300.

Type locality

Pool along Great Northern Highway, near Cue, WA, approximate coordinates: 27º 15’ 20”S 117º 58’ 58”E. All specimens collected by SH on 6 Sep. 2006.

Type material

Holotype

Male ( WAM.C49406 ), with soft parts dissected in a sealed slide, RV stored dry in a micropalaeontological slide (LV lost).

Allotype

A carapace of a female ( WAM.C49407) stored dry in a micropalaeontological slide.

Paratypes

Three males ( WAM.C49408-49409, OC.3319) dissected and stored as the holotype; two male carapaces ( WAM.C49410).

Several specimens in EtOH ( WAM.C49411).

Other material investigated

The species is thus far 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 – it is the largest species here described), 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 considerable dorsal overlap of the RV by the LV, the straight dorsal margin of the LV, the elongated lapel running parallel to the selvage, the rather narrow second segment of the Rpp, the fact that tip of ls and ms of the hemipenes are well-separated from each other and that the ls extends much longer than the ventral lobe of the ms. Bennelongia cuensis sp. nov. is similar to the previously described species, B. lata sp. nov., especially in the shape of the lapel on the RV, but can be easily distinguished by the shape of the carapace in right lateral view (rounded with limited dorsal overlap in B. lata sp. nov., sub quadrate with considerable dorsal and ventral overlap in B. cuensis sp. nov.) and especially by the shape of the ms on the hemipenis (ventrally bluntly pointed and short and without dorsal lobe in B. lata sp. nov., with elongated and narrow lobes on both dorsal and ventral sides in B. cuensis sp. nov.)

Additional description

Valves ( Figure 18A, B ) in lateral view with straight dorsal margin, LV overlapping RV on all sides ( Figure 18G, H ), but with considerable dorsal overlap, greatest height situated in the middle; in dorsal and ventral views ( Figure 18 C-F) 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 18A ) in inner view with rather straight dorsal margin, greatest height situated in the middle; antero-ventral beak-like expansion moderate and rounded; ventral margin slightly sinuous in the middle.

RV ( Figure 18B ) in inner view with greatest height situated slightly in front of the middle, dorsal margin rounded; posterior selvage sub marginal, posterior inner list merging with posterior selvage; remnant of valve margin visible between lapel and valve margin; antero-ventral inner list running to about halfway

the lapel; selvage at height of lapel expanded, striate; lapel ( Figure 18 I-K) broad, running parallel to selvage, slightly striate.

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

Rpp ( Figure 17D ) with first segment c 1.5 times as long as wide, subapically with one long but slender, and one short sensory organ; second palp segment elongate, with narrow base, apically with one small sensory organ.

Lpp ( Figure 17G, H ) with first segment elongated, more than twice as long as central width, subapically with one long, stout sensory organ; apically with small, rounded 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 17E, F ) asymmetrical, with tips of ls and ms well-separated, ls extending well beyond ms, ventral part of ms produced into an elongated, pointed lobe, dorsally also extending beyond peniferum with a rounded lobe; distal part of ls bluntly pointed with distal margin rounded in one hemipenis, with elongated thumb-like expansion in the other.

Ecology and distribution

The species is known from its type locality only, a small seasonal claypan with fresh turbid water. No further environmental data are available.

Figures

Fig. 17. A-C. Bennelongia lata sp. nov. (holotype ♂, WAM.C49399); D-H. Bennelongia cuensis sp. nov. (D-G = holotype ♂, WAM.C49406; H = OC.3319). A. Left prehensile palp and detail of apical sensory organs on first segment. B. outline of hemipenes (note that distal shield is folded in left hemipenis). C. Right prehensile palp. D. Right prehensile palp. E. Outline of hemipenis. F. Outline of second hemipenis, same individual. G. Left prehensile palp. H. Left prehensile palp. Scales: B, E, F = 232 µm,; A, C, D, G, H = 92 µm; A’ = 37 µm.

Fig. 18. Bennelongia cuensis sp. nov. (all from pan near Cue, type locality). A. LVi (♂, WAM.C49408). B. RVi (♂, Idem). C. Cp dorsal (♀, specimen lost). D. Cp ventral (♀, same specimen lost). E. Cp ventral (♂, WAM.C49410A). F. Cp dorsal (♂, Idem). G. CpRL (allotype ♀, WAM.C49407). H. CpRL (♂, WAM.C49410B). I. RVi (detail anteriorly, ♂, WAM.C49408). J. RVi, detail anteriorly (tilted ♂, Idem). K. RVi (detail anteriorly, tilted ♂, Idem). Scales: A-H = 1000 µm; I-K = 200 µm.