Bennelongia gwelupensis, 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 : 29-30

Bennelongia gwelupensis sp. nov.

( Figs 14 C-F, 15)

Bennelongia australis ( Brady, 1886) – Davies & Christidis 1997: 81, figs 8.3.21a,b.

Etymology

Named after the type locality, Lake Gwelup, Perth.

Diagnosis

Cp with pronounced anterior rostrum, and weaker posterior rostrum. LV with pronounced anteroventral beak and rounded dorsal margin. Lapel on RV almost evenly rounded, dorsally sloping towards valve margin. Hemipenis with MS with straight margin, ventrally widely produced as a bluntly pointed lobe; ls in both hemipenes evenly rounded, distally with blunt tip; tips of ls and ms well-separated, ls and ms nearly equally long. Rpp with distal segment triangular, relatively elongated. Lpp with proximal segment bearing rectangular apical outgrowth with rounded tip; distal segment sickle-shaped, elongated, as long as first segment, and with almost parallel margins, except for distal part.

Measurements (all measurements in µm)

Female: RV: L = 1710; H = 1040. LV: L = 1830; H = 1110. Cp: L = 1610-1820; H = 1080; W = 860-916.

Type locality

Lake Gwelup, Perth (WA); approximate coordinates: 31º 52’ 37”S 115º 47’ 18”E. Material used for the present description collected on 23 Dec. 2008 and on 15 July 2010 by the authors.

Type material

Holotype

A female ( WAM.C49394 ), with soft parts dissected in glycerine in a sealed slide, valves stored dry in a micropalaeontological slide.

Allotype

As the population collected at the type locality is fully parthenogenetic, no males occurred (at least at the time of collection) and no allotype can be designated.

Paratypes

Four female carapaces ( WAM.C49395A-D) and several in toto specimens in EtOH ( WAM.C49396).

Other material investigated

Big Carine Swamp, Perth, collected by the authors on 15 July 2010, approximate coordinates: 31º 51’ 08”S 115º 47’ 04”E.

Several pools between Bunbury and Perth, collected by the authors on 04 July 2010 and 31 July 2010. The only male found thus far was in a dense population in a large ditch next to a parking lot beside Forrest Highway, just northeast of the Greenlands Road intersection, 32º 38’ 29”S 115º 48’ 34”E (sample MR/10). Specimens from this locality: a male ( WAM.C49397) dissected and stored as the holotype; 3 female carapaces ( WAM.C49398A-C). All other pools, as well as Lake Gwelup and Big Carine Swamp, held only parthenogenetic populations.

Small unnamed streamlet, inflowing in Leschenault Estuary, collected by the authors on 04 July 2010 and 31.7.2010 This is the most southern locality thus far of this species; approximate coordinates: 33º 19’ 10.3”S 115º 41’ 17.3”E (sample MR/09). Specimens from this locality: RV +LV of one female and a Cp of a female (OC.3316A-B);

Differential diagnosis

This 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 rounded dorsal margin of the LV, the rounded lapel, the rather narrow second segment of the Rpp, the fact that tips of ls and ms of the hemipenes are wellseparated from each other and that ls and ms are almost equally long.

Additional description

Valves in lateral view with rounded dorsal margin ( Figure 15 A-B), LV overlapping RV on all sides ( Figure 15C, H ), greatest height anterior to the middle; in dorsal and ventral view ( Figure 15E,G ) with greatest width in the middle of the carapace; anterior rostrum well-developed ( Figure 15F ), posterior side bluntly pointed, LV dorsally ridge-like; external surface weakly pitted and almost devoid of setae.

LV ( Figure 15A ) in inner view with rounded dorsal margin, greatest height situated anterior to the middle; antero-ventral beak-like expansion rather large; ventral margin almost straight over most of its length.

RV ( Figure 15B ) in inner view with greatest height situated well in front of the middle, dorsal margin almost straight for about the middle third; posterior selvage submarginal, posterior inner list merging with posterior selvage at about halfway the length of the latter; lapel ( Figure 15G, I, J ) rounded, dorsally sloping towards the valve margin, ventrally gently curving towards it; antero-ventral inner list running to about halfway the lapel; selvage at height of lapel expanded, not striate.

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

Rpp ( Figure 14C ) 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 triangular, rather elongate, with sinuous distal margin; apically with one small sensory organ.

Lpp ( Figure 14E ) with first segment elongated, more than twice as long as central width, subapically with one long but slender sensory organ, slightly swollen in the middle; apically with a short and distally rounded outgrowth, bearing one very small sensory organ; second palp segment nearly straight, sickleshaped and relatively elongated (L = L of first segment); distal part of this segment straight and with nearly parallel margins.

Hemipenes ( Figure 14D, F ) symmetrical, with tips of ls and ms well separated from one another, ls and ms almost equally long, distal part of ms produced into an elongated lobe; distal part of ls bluntly pointed with distal margin rounded.

Ecology and distribution

The species is common in Perth wetlands, where it occurs in large populations most of the year, and along the south-west coast of Western Australia. Its most southern known locality is a small stream entering Leschenault Estuary in Bunbury, where it occurred together with Cyprideis australiensis and Eucypris virens . The species has been recorded in water with conductivity 483-3880 µS cm-1 and pH 6.8.

Remarks

Davies & Christidis (1997) mention the presence of B. australis in 11 Perth wetlands. We have been able to identify two of these populations (Lake Gwelup, Big Carina swamp) as B. gwelupensis sp. nov., but most likely all of the populations of these 11 wetlands belong to this species.

Figures

Fig. 14. A-B. Bennelongia coondinerensis sp. nov. (holotype ♂, WAM.C49389); C-F. Bennelongia gwelupensis sp. nov. (♂, WAM.C49397). A. Hemipenis outline. B. Other hemipenis, showing inner anatomy. C. Right prehensile palp. D. Hemipenis outline. E. Left prehensile palp. F. Outline of second hemipenis, same individual. Scales: D, F = 232 µm; A, B, C, E = 92 µm.

Fig. 15. Bennelongia gwelupsensis sp. nov. (all ♀, from Lake Gwelup, Perth – type locality). A. LVi (holotype ♀, WAM.C49394). B. RVi (Idem). C. Cp RL (WAM.C49395A). D. CpV (detail anteriorly, WAM.C49395B). E. CpD (WAM.C49395C). F. Cp anteriorly (animal inverted) (WAM. C49395D). G. CpV (WAM.C49395B), H. CpRL (detail anteriorly, WAM.C49395A). I. RVi (detail anteriorly, holotype ♀, WAM.C49394). J. RVi (detail anteriorly, tilted, Idem). Scales: A-C, E,G = 1000 µm; F = 500 µm; D,H-J = 200 µm.