Bennelongia calei sp. nov.

Figs 21-22

urn:lsid:zoobank.org:act: DBD2498B-9E05-4E2A-9597-67844A85653E

Bennelongia barangaroo – De Deckker 1981a: 104, fig. 9 (partim).

Diagnosis (based on type specimens)

Valves (Fig. 21 A-B, E-F) elongated, with greatest height situated close to the middle, dorsal margin evenly sloping towards the posterior side; ventral margin almost straight. LV (Fig. 21A, E) with anteroventral il large and reaching beyond middle of valve, antero-dorsal il descending to about halfway along antero-ventral il. RV (Fig. 21B, F) with antero-ventral lapel large, elongated and wide, with crenulated edge (Fig. 21 C-D, G-H). Carapace in dorsal and ventral views (Fig. 21 K-L) with greatest width in the middle, most slender of all species described here, external surface rather smooth to weakly pitted, set with only few short setae; anteriorly with a clearly delimited rostrum. Carapace in right lateral view (Fig. 21 I-J) with greatest height in the middle, dorsal margin evenly sloping to bluntly rounded posterior margin; anteriorly with the widest LV>RV overlap of all species described here.

Males unknown.

Etymology

This species is named after D.J. Cale (Woodvale, WA) in honour of his longstanding contribution to the knowledge of freshwater invertebrates in WA, including at Fraser Lake which is the type locality of the present species (Cale et al. 2004), and also in recognition of the fact that he has collected so many of the samples used for the present revision of the Bennelongia barangaroo lineage.

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

Holotype ♀ (WAMC52335): RV: L = 1480, H = 857. LV: L = 1555, H = 865.

Type locality

Fraser Lake, ca. 8 km SE of Dowerin, WA. Approximate coordinates: 31º15’18.0” S, 117º4’22.0” E (WGS 84). All material (sample code DJC/18) collected on 23 Sep. 2011 by D.J. Cale with a sweep net. Water chemistry at time of collecting: K25 1.76 mS/cm, pH 8.1, water temperature 23.9 ºC.

Type material

Holotype

♀ (WAMC52335) valves stored dry in a micropalaeontological slide.

Allotype

As males are unknown, no allotype is designated.

Paratypes

Eight ♀♀, either as dried valves or carapaces (WAMC 52337-52341; OC.3344-3345). Ca. 45 females stored as bulk in EtOH (WAMC 52342).

Other material investigated

Fraser Lake (type locality). Four ♀♀ valves and carapaces stored dry (WAMC 52353-52356) from the same locality, but collected on another date (sample nr SPM 017B, collected by D.J. Cale, 24 Nov. 2000), were also used during the present assessment of this species but are not considered as type material here. Second pool along Carnamah-Eneabba Road on south side (Eneabba Springs). Approximate coordinates: 29°48’23.62’’ S, 115°25’6.11’’ E (sample DJC /10), collected by D.J. Cale on 10 Sep. 2011 (one ♀ WAMC 52349). Water chemistry at time of collecting: K25 3.19 mS/cm, pH 6.6, water temperature 20.9 ºC.

Jerramungup West. Approximate coordinates: 33°59’16.03’’ S, 118°56’28.15’’ E (sample DJC /36), collected by D.J. Cale on 21 Oct. 2011 (five ♀♀ valves and carapaces stored dry WAMC 52350-52352; OC.3348-3349). Water chemistry at time of collecting: K25 0.73 mS/cm, pH 8.74, water temperature 25.8 ºC

Oak Flat W pit gnamma via Goomalling. Approximate coordinates 31º08’21” S, 116º52’46” E (sample BVT /11/04), collected by B. V. Timms on 16 Aug. 2011 (four ♀♀ valves and carapaces stored dry WAMC 52343-52344; OC.3346-3347).

Horse Collar gnamma, on Magee Rd via Kulin. Approximate coordinates: 32º48’04” S, 118º23’34” E (sample BVT /11/05), collected by B. V. Timms on 4 Sep. 2011 (four ♀♀ valves and carapaces stored dry WAMC 52345-52348).

Additional illustrations

Several other populations of this species were found and for four of these (listed above), valves of female specimens are also illustrated here (Fig. 22). All of these specimens comply with the above diagnosis, and where specimens were available for molecular analyses, they also fell into the B. calei sp. nov. – cluster. No cryptic species were identified in this species.

Differential diagnosis

Bennelongia calei sp. nov. can easily be distinguished from all other species in the B. barangaroo lineage by the elongated and stout antero-ventral lapel on the RV, which is slightly rounded and has a

crenulated distal margin, the large anterior LV>RV overlap, the stout antero-ventral il on the LV and the clear anterior rostrum on the carapace in dorsal or ventral view.

Ecology and distribution

The species is most common in pools and lakes in the southwest of WA. However, B. calei sp. nov. was also recovered from a totally different kind of habitat, namely pit gnammas near Goomalling (BVT/11/04) and Kulin (BVT/11/05). Whereas the other species in this lineage apparently occur either in rock pools or in soft bottomed pools and lakes, B. calei sp. nov. can apparently survive in both (very different) types of habitats. Bennelongia calei sp. nov. is, together with B. timmsi sp. nov. and B. scanloni sp. nov., one of the more common species in its area.