Bennelongia nimala De Deckker, 1981

Martens, Koen, Halse, Stuart & Schön, Isa, 2015, On the Bennelongia nimala and B. triangulata lineages (Crustacea, Ostracoda) in Western Australia, with the description of six new species, European Journal of Taxonomy 111, pp. 1-36 : 11-13

Bennelongia nimala De Deckker, 1981

Fig. 4 A–N

Bennelongia nimala n. sp. – De Deckker, 1981: 105 –108, figs 10–11.

Abbreviated redescription.

Valves in inner view ( Fig. 4 A–B) relatively high, with almost straight dorsal margin and greatest height situated well in front of the middle; ventral margin anteriorly without mandibular curve. LV ( Fig. 4A ) with antero-distal il running all the way down into the beak, but not connecting with ventral inner list; antero-proximal il running slightly over halfway along the anterior margin; posterior il tuberculate and running halfway up the posterior margin, next to the pointed valve margin. RV ( Fig. 4B ) with anteroventral lapel large, ventrally pointed and heavily serrated ( Fig. 4 L–N). Both valves with heavy external ornamentation, consisting of pits, smaller and larger tubercles ( Fig. 4 C–D, F–G, K).

Cp ( Fig. 4G, K, M ) with LV overlapping RV on all sides, but moderately so; CpRL with LV forming an antero-dorsal hump over RV. CpD with greatest width situated in the middle in females ( Fig. 4G ), anteriorly with strong and slightly asymmetrical rostrum, dorsally set with parallel rows of tubercles.

From De Deckker (1981): Soft parts as typical of the genus. Hemipenis with lobe ls broad and plump, antero-ventral extremity broadly rounded; lobe ms with antero-ventral extremity broad and rounded. Rpp with unusually long and narrow distal segment. Lpp with sickle-shaped terminal segment, relatively long and slender, also proximal segment long and narrow.

New material investigated

Kakadu National Park, Coonjimba Billabong, Gulungul Creek, Ranger, Jabiru region, NT (sample CNJ-R-109). Approximate coordinates: 12°34’37” S, 132°52’30.1” E. Collected by Russell Shiel on 9 May 2009. Several females (WAMC55591–55593).

Kakadu National Park, Corndori Billabong, Gulungul Creek, Ranger, Jabiru region, NT (sample CORN 9/v/09). Approximate coordinates: 12°37’50” S, 120°53’06” E. Collected by Russell Shiel on 9 May 2009. Several females (WAMC55594, OC3373).

Unnamed lagoon, Adelaide River Floodplain, NT (sample NT/12/01). Approximate coordinates: 12°53’06.5” S, 131°12’03.0” E. Collected by the authors on 28 Jul. 2012. Several females (OC3371– 3372, WAMC55585–55586, 55589). K25 = 58 µS/cm, Temp = 30,2°C, pH = 8.0, depth = ca. 0.3 m.

Bennett Dam, Adelaide River Floodplain, NT (sample NT/12/03). Approximate coordinates: 12°57’08.3” S, 131°09’59.7” E. Collected by the authors on 25 Jul. 2012. Several females (WAMC55587–55588). K25 = 58 µS/cm, Temp = 28°C, pH = 7.2, depth = ca. 0.5 m.

Unnamed lagoon, Mary River Park, NT (sample NT/12/08). Approximate coordinates: 12°54’52.1” S, 131°39’23.7” E. Collected by the authors on 26 Jul. 2012. Several females (WAMC55590).

Type locality

Georgetown Lagoon, Jabiru, NT.

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

Measurements of type material from De Deckker (1981):

Holotype ♂: RV: L = 1340, H = 760, LV: L = 1500, H = 840.

Paratype ♀: RV: L = 1540, H = 860; LV: L = 1640, H = 960.

Measurements of new material (only ♀♀):

RV: L = 1450–1550, H = 780–900; LV: L = 1480–1750, H = 870–1010, W = ca. 1020.

Differential diagnosis

The species can be separated from all other congeners belonging to the B. nimala lineage by the pointed caudal section of the LV and by the large, pronounced and heavily serrated lapel on the RV. The moderate antero-ventral LV/RV overlap distinguishes this species specifically from B. tirigie sp. nov., B. koendersae sp. nov. and B. muggon sp. nov.

Ecology and distribution

Bennelongia nimala is an NT species. It occurs in vegetated and unvegetated freshwater lagoons, from which it derives its name.

Figures

Fig. 4. Bennelongia nimala De Deckker, 1981 (all ♀, all from Kakadu National Park, NT). A. LVi (WAMC55593). B. RVi (WAMC55593). C. RVe (WAMC55589). D. LVe (WAMC55589). E. RVi, detail of central muscle scars (WAMC55593). F. LVe, detail of surface ornamentation (WAMC55589). G. CpD (OC3373). H. LVi, detail of caudal side (WAMC55593). I. LVi, detail of anterior side (WAMC55593). J. CpD (juvenile A-3, specimen lost). K. CpRL (OC3373). L. RVi, detail of anterior margin (WAMC55593). M. CpRL, detail of anterior margin, showing external view of lapel (OC3373). N. RVi, tilted, detail of anterior margin and of lapel (WAMC55593). Scale = 1 mm for A–D, G, K; 500 µm for J; 200 µm for E–F, H–I, L–N.