Bennelongia hirsuta sp. nov.

Figs 13 F-I, 14

urn:lsid:zoobank.org:act: CDE0D1E7-52E6-4F18-B6FF-B3AD48C6E4B4

Diagnosis

Valves elongated, with greatest height situated well in front of the middle, dorsal margin evenly sloping towards the posterior side; ventral margin anteriorly with pronounced mandibular curve. LV (Fig. 14A, D) with antero-ventral inner list large, well-overlapping the dorsal il. RV (Fig. 14B, E) with anteroventral lapel long, narrow and weakly crenulated (Fig. 14 J-M).

Carapace in dorsal and ventral view (Fig. 14 G-I) with greatest width in the middle, most hirsute, anteriorly with a clear rostrum; in lateral views (Fig. 14C, F) anteriorly with a clear LV>RV overlap.

Hemipenes asymmetrical (Fig. 13F, I), ls with slender base, ventrally sharply beak-shaped and pointed, only slightly protruding beyond ventral tip of ms. Right prehensile palp (Fig. 13G) with distal segment stout and subquadrate, anterior margin straight, dorsal margin sinuous. Left prehensile palp (Fig. 13H, H’) with distal segment short and sickle-shaped, reaching beyond ventro-apical margin of proximal segment with less than a third of its length.

Etymology

Named after the hirsute (‘hairy’) nature of this species. All species of the B. barangaroo lineage are hirsute to some extent, but the present species is more so, with the entire carapace set with long and stiff setae.

Measurements (all measurements in µm – see Table 1 for measurements of all specimens illustrated with SEM)

Holotype ♂ (WAMC52269): RV: L = 1260, H = 738. LV: L = 1320, H = 763.

Allotype ♀ (WAMC52270): RV: L = 1400, H= 842. LV: L = 1470, H = 845.

Type locality

Rock pools (gnammas) on Styles Rock, WA, ca. 80 km N of Esperance. Approximate coordinates: 33º07’35” S, 121º48’02” E (WGS 84). All specimens (voucher sample OSTR012D; locality code SPS139), collected on 07 Sep. 1998 by J. McRae & A. Pinder with a sweep net.

Type material

Holotype

♂ (WAMC52269), with soft parts dissected in a sealed slide and valves stored dry in a micropalaeontological slide.

Allotype

♀ (WAMC52270), with soft parts dissected in a sealed slide, and valves stored dry in a micropalaeontological slide.

Paratypes

Numerous ♂♂ and ♀♀, as valves or carapaces (WAMC 52271-52277; OC.3323-3325). Nine ♂♂ and ♀♀ in bulk in EtOH (WAMC 52278).

Other material investigated

? One ♀ (WAMC 52279) from Lilian Stokes Rocks (BVT /10/09) (identification uncertain).

Differential diagnosis

Bennelongia hirsuta sp. nov. can be distinguished from all other species in the B. barangaroo lineage by the pointed shape of the ls in the hemipenis. Also the shapes of the distal segments of the prehensile palps are distinctive. In valve morphology, the species is easily recognisable by the long and narrow lapel on the RV (which is nevertheless very difficult to see with a normal binocular microscope) and the large antero-ventral il.

Ecology and distribution

The species is thus far only known with certainty from its type locality, a set of rock pools on Styles Rock.