Bennelongia scanloni, Martens & Halse & Schön, 2013

Martens, Koen, Halse, Stuart & Schön, Isa, 2013, On the Bennelongia barangaroo lineage (Crustacea, Ostracoda) in Western Australia, with the description of seven new species, European Journal of Taxonomy 66, pp. 1-59 : 39-44

Bennelongia scanloni sp. nov.

Figs 18-20

urn:lsid:zoobank.org:act:B41BF127-BEEC-47CE-A687-FACD6CBCF028

Diagnosis

Valves ( Fig. 18 A-B, D-E) high, with greatest height situated close to the middle, dorsal margin evenly sloping towards the posterior side; ventral margin sinuous. LV ( Fig. 18A, D ) with antero-ventral il of medium size, covering lower third of valve, antero-dorsal il descending to about halfway along anteroventral il. RV ( Fig. 18B, E ) with antero-ventral lapel tear-shaped in untilted lateral view; in tilted view, lapel subtriangular with rounded ventral point ( Fig. 18 K-N). Carapace in dorsal and ventral views ( Fig. 18 G-J) with greatest width in the middle, hirsute and pitted, anteriorly with a clear rostrum; in right lateral view ( Fig. 18C, F ) with large anterior LV>RV overlap, anterior margins of RV and LV not parallel.

Hemipenes (holotype: Fig. 20F ) asymmetrical, ls with broad base, ventrally bluntly pointed (more so in one hemipenis than in the other), largely protruding beyond ventral tip of ms. Right prehensile palp (holotype: Fig. 20D ) with distal segment stout and subquadrate, with sharp angle between anterior and dorsal margins, both of these margins almost straight. Left prehensile palp (holotype: Fig. 20E ) with distal segment sickle-shaped and of intermediate length, reaching beyond ventro-apical margin of proximal segment with about half of its length.

Etymology

The species is named in honour of Mike Scanlon (Perth, WA) in acknowledgement of his unrelenting technical help since 2006 towards the present revision of Bennelongia .

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

Holotype ♂ ( WAMC52291 ): RV: L = 1223, H = 694. LV: L = 1294, H = 714.

Allotype ♀ ( WAMC52292 ): RV: L = 1263, H =752. LV: L = 1356, H = 775.

Type locality

One Tree Hill Creek, ca. 62 km SE of Dongara, WA. Approximate coordinates: 29º35’19.0” S, 115º26’31.0” E (WGS 84). All specimens (sample DJC/11; locality code SPS180) collected by D.J. Cale on 10 Sep. 2011 with a sweep net. Water chemistry at time of collecting: K25 5.62 mS/cm, pH 6.68, water temperature 20.8 ºC.

Type material

Holotype

♂ ( WAMC52291 ), with soft parts dissected in a sealed slide and valves stored dry in a micropalaeontological slide.

Allotype

♀ ( WAMC52292 ) valves stored dry in a micropalaeontological slide.

Paratypes

Numerous males and females either as dissection, or as valves or carapaces stored dry ( WAMC 52293- 52304; OC.3329-3331). Ca. 30 ♂♂ and ♀♀ stored as bulk in EtOH ( WAMC 52305).

Other material investigated

One Tree Hill Creek. 29º35’19.0” S, 115º26’31.0” E, collected by S. Halse and A. Pinder on 11 Aug. 1999 ( OSTR 013C), see Fig. 20 G-J ( WAMC 52327). Water chemistry at time of collecting: K25 3.12 mS/ cm, pH 7.65, water temperature 19.4 ºC.

Pools at Latham-Coorow Rd. 29º51’S, 116º16’ E (sample BVT /10/10), collected by B. V. Timms on 10 Sep. 2010 ( WAMC 52306-52308; OC.3332-3333).

Dam at Solomons Well. Approximate coordinates: 31°11’58.8” S, 116°21’47.7” E (sample DJC /04), collected by D.J.Cale on 09 Sep. 2011 (4 ♀♀: WAMC 52332-52334; OC.3343). Water chemistry at time of collecting: K25 0.12 mS/cm, pH 7.85, water temperature 14.4 ºC.

Three Pools along Eneabba-Carnamah Rd. Approximate coordinates: 34°18’32.80” S, 115°39’16.44’’ E (sample DJC /09), collected by D.J. Cale on 10 Sep. 2011 (2 ♀♀: WAM 52310; OC.3334). Water chemistry at time of collecting: K25 8.7 mS/cm, pH 7.2, water temperature 20.3 ºC.

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. Water chemistry at time of collecting: K25 3.19 mS/cm, pH 6.6, water temperature 20.9 ºC.

Petruder Dam. Approximate coordinates: 30°25’20.87’’ S, 116°57’39.43’’ E (sample DJC /15), collected by D.J. Cale on 11 Sep. 2011 (5 ♀♀: WAMC 52329-52331, OC.3341-3342). Water chemistry at time of collecting: K25 0.16 mS/cm, pH 7.85, water temperature 22.0 ºC.

Tin Dog Creek. Approximate coordinates: 31°11’53.5” S, 117°01’41.4” E (sample DJC /19), collected by D.J. Cale on 23 Sep. 2011 (♀♀: WAMC 52311-52315, OC.3335-3336. Juveniles: WAMC 52316- 52318). Water chemistry at time of collecting: K25 1.56 mS/cm, pH 7.06, water temperature 24.2 ºC.

Pools near Brookton Hwy (in Warrine Park). Approximate coordinates: 32°23’50.4” S, 116°48’00.4” E (sample DJC /23), collected by D.J. Cale on 01 Oct. 2011 (4 ♀♀: WAMC 52319-52321, OC.3337). Water chemistry at time of collecting: K25 0.44 mS/cm, pH 8.1, water temperature 21.6 ºC.

Three Springs Tumulus Stream. 29º35’31” S, 115º27’1” E, collected by A. Pinder on 29 Sep. 2010 (1 male: OC.3338; 2 ♀♀: WAMC 52322-52323).

East Lake Bryde. 33º21’ S, 118º49’ E (sample BRYDE 7), collected by D.J. Cale on 22 Mar. 2006 (4 ♀♀: WAMC 52324-52326; OC.3339). Water chemistry at time of collecting: K25 0.17 mS/cm, pH 6.91, water temperature 25.8 °C.

Lake Cronin. Episodically filled waterbody with extensive shrub and Melaleuca fringe, collected by S. Halse and A. Pinder on 25 Sep. 1997. Approximate coordinates: 32°23’02” S, 119°45’51” E. Water chemistry at time of collecting: K25 0.23 mS/cm, pH 9.48, water temperature 18.0 °C. Material investigated: one dissected ♀ (nr OS.544), with soft parts in a sealed slide and valves stored dry in micropalaeontological cavity slide (illustrated: Fig. 24 E-H).

Reserve Esperance 26140 near Munglinup. Seasonally filled lake with trees across most of flooded area, collected 27 Oct. 1986 by S. Halse. Approximate coordinates: 33°26’24” S, 120°31’48” E. Water chemistry: salinity 0.27 mg /L TDS, pH 6.93. Material investigated: one dissected ♀ (nr OS.604), with soft parts in a sealed slide and valves stored dry in a micropalaeontological cavity slide (illustrated: Fig. 25 I-L).

Remarks on the latter two localities: the lapels of both specimens are slightly larger than in most specimens of B. scanloni sp. nov. and as (1) no males are at hand to check for the morphology of the hemipenes and the prehensile palps in these populations and (2) no molecular data are available, the identifications of these two specimens are tentative.

Additional notes on cryptic species

Specimens from the type locality (One Tree Hill Creek, sample DJC/11) all belong to cryptic species E1, which is thus the true B. scanloni sp. nov. s.s. Also specimens from sample DJC/23 (pools near Brookton Hwy in Warrine Park) belong to this lineage ( Fig. 19 I-O). Two specimens from cryptic species B2 are also illustrated here, one female from pools beside Latham-Coorow Rd (western Wheatbelt) (BVT/10/10) ( Fig. 19 A-D) and one female from Tin Dog Creek (DJC/19) ( Fig. 19 E-H). There are no clear differences between the two cryptic species in valve morphology.

The soft parts of the male from Three Springs Tumulus Stream (TST) ( Fig. 20 A-C) are slightly different from those of the holotype ( Fig. 20 D-F). Yet, within the molecular phylogeny the TST specimens cluster closely with the cryptic species E1, which is the same as for the type specimens. The hemipenis outline and the prehensile palps of the male from OSTR013C ( Fig. 20 G-J) are almost identical to those of the holotype, though no molecular data on this population are available, and it is thus also not clear to which of the two cryptic species within B scanloni sp. nov. this specimen belongs.

Thus far, the two molecular species cannot be distinguished morphologically. Interestingly, these two cryptic lineages occur sympatrically in no less than 4 localities (DJC/09, DJC/11, DJC/19 and BVT/10/10).

Differential diagnosis

The drop-shaped lapel on the RV and the sharp angle on the distal margin of the terminal segment of the right prehensile palp distinguish B. scanloni sp. nov. from all other species within the B. barangaroo lineage.

Ecology and distribution

This is arguably the most common species in this lineage in the south-western part of WA. It typically occurs in pools, dams and lakes with soft sediments.

Figures

Fig. 18. Bennelongia scanloni sp. nov., type specimens from type locality (One Tree Hill Creek, DJC/11). A. ♀ allotype, LVi (WAMC52292). B. ♀ allotype, RVi (idem). C. ♀ paratype, CpRL (WAMC52299). D. ♂ paratype, LVi (OC.3329). E. ♂ paratype, RVi (idem). F. ♂ paratype, CpRL (WAMC52295). G. ♀ paratype, CpD (WAMC52297). H. ♀ paratype, CpV (WAMC52298). I. ♂ paratype, CpV (WAMC52295). J. ♂ paratype, CpD (WAMC52296). K. ♀ allotype, RVi, detail anterior (WAMC52292). L. ♀ allotype, RVi, detail anterior, tilted (idem). M. ♂ paratype, RVi, detail anterior (OC.3329). N. ♂ paratype, RVi, detail anterior, tilted (idem). Scales: A-J = 1 mm; K-N = 200 µm.

Fig. 19. Bennelongia scanloni sp. nov., non-type specimens. — A-D. Pool at Latham-Coorow Rd (BVT/10/10, ♀, WAMC52307)). A. LVi. B. RVi. C. RVi, detail anterior. D. RVi, detail anterior, tilted. — E-H. Tin Dog Creek (DJC/19, ♀, OC.3335). E. LVi. F. RVi. G. RVi, detail anterior. H. RVi, detail anterior, tilted. — I-O. Pool at Brookton Hwy (Warrine Park) (DJC/23, ♀, OC.3337). I. LVi. J. RVi. K. RVi, detail anterior. L. RVi, detail anterior, tilted. M. LVe, detail anterior. N. RVe. O. RVe, detail anterior. Scales: A-B, E-F, I-J, N = 1 mm; C-D, G-H, K-M, O = 200 µm.

Fig. 20. Bennelongia scanloni sp. nov., males. — A-C’. Non-type (OC.3338, Three Springs Tumulus Stream - TST): A. Hemipenis (both hemipenes symmetrical in this specimen). B. Right prehensile palp. C. Left prehensile palp. C’. Idem, detail of ventro-apical part of first segment. — D-F. Holotype (WAMC52291, One Tree Hill Creek – DJC/11): D. Right prehensile palp. E. Left prehensile palp. F. Hemipenis (both hemipenes symmetrical in this specimen). — G-J. Non-type (WAMC52327, from OSTR013C): G. Hemipenis. H. Right prehensile palp. I. Left prehensile palp. I’. Idem, detail of ventroapical part of first segment. J. Hemipenis. Scale: A-J = 92 µm; C’, I’ = 37 µm.

Fig. 24. Bennelongia spp. (no museum nrs), females. — A-D. Bennelongia sp. X1. Crane Pan (OS.255). A. LVi. B. RVi. C. RVi, detail anterior. D. RVi, detail anterior, tilted. — E-H.? Bennelongia scanloni sp. nov., Lake Cronin (OS.544). E. LVi. F. RVi. G. RVi, detail anterior. H. RVi, detail anterior, tilted. — I-L. Bennelongia dedeckkeri, Lake Gregory (OS.260). I. LVi. J. RVi. K. RVi, detail anterior. L. RVi, detail anterior, tilted. Scales: A-B, E-F, I-J = 1 mm; C-D, G-H, K-L = 200 µm.

Fig. 25. Bennelongia spp. (no museum nrs). — A-D. Bennelongia sp. X2, Three Springs Tumulus Stream (♀, KMWA.917). A. LVi. B. RVi. C. RVi, detail anterior. D. RVi, detail anterior, tilted. — E-H. Bennelongia sp. nov. E2, BYK (♀, KMWA.806) = Species E2 in Figs 2-3. E. LVi. F. RVi. G. RVi, detail anterior. H. RVi, detail anterior, tilted. — I-L.? Bennelongia scanloni sp. nov., pool near Esperance (♀, OS.004). I. LVi. J. RVi. K. RVi, detail anterior. L. RVi, detail anterior, tilted. Scales: A-B, E-F, I-J = 1 mm; C-D, G-H, K-L = 200 µm.