Bennelongia dedeckkeri, Shearn, Koenders, Halse, Schon & Martens, 2012

Shearn, Rylan, Koenders, Annette, Halse, Stuart & Martens, Isa Schön and Koen, 2012, A review of Bennelongia De Deckker & McKenzie, 1981 (Crustacea, Ostracoda) species from eastern Australia with the description of three new species, European Journal of Taxonomy 25, pp. 1-35 : 10-13

Bennelongia dedeckkeri sp. nov.

urn:lsid:zoobank.org:act:E1020EC3-B809-4FDF-876D-822C46A241D6

Figs 4-5

Diagnosis

Cp relatively small (L = 1000 µm), with similar size and appearance between sexes; in dorsal view with reduced anterior rostrum, blunt posterior and reduced anteroventral overlap of LV over RV; in lateral view with rounded dorsal margin; LV with less developed anteroventral beak-like structure, rounded dorsal margin; RV with straight posterodorsal margin (hinge), greatest height slightly anterior of the middle, short and ventrally pointed anteroventral lapel present; hemipenes with ls protruding well beyond ms, tips of ls and ms separated, ls distally pointed; distal Rpp segment with pointed dorsal margin, proximal segment with rounded ventral margin and nearly straight dorsal margin; Lpp proximal segment elongated with subapical sensory organ, distal segment sickle shaped, shorter than proximal segment and sharply curved over 180°.

Etymology

The species is named after Dr P. De Deckker, who described the Bennelongia genus with Dr K. McKenzie in 1981.

Type material

Holotype

Ƌ (W40075), with soft parts dissected in a sealed slide, RV and LV stored dry in a micropalaeontological slide.

Allotype

♀ (W40018), with soft parts dissected in a sealed slide and valves stored dry in a micropalaeontological slide.

Paratypes

Three Ƌ carapaces stored in a micropalaeontological slide (W40021-W40023), 3 ♀ carapaces stored in a micropalaeontological slide (W40024-W40026), 2 ƋƋ with soft parts dissected in a sealed slide and valves stored in a micropalaeontological slide (W40016-W40017), ♀ LV stored in a micropalaeontological slide (W40020) and ♀ RV stored in a micropalaeontological slide (W40019).

Several in toto specimens in EtOH (W40076).

Type locality

Lake Galilee, south bank, approximately 70 km north-east of Aramac QLD, coordinates: 22º25’55.4” S - 145º42’27.2” E. Material used for the present description was collected on 07 Jun. 2011 by RS and AK (Sample QLDP 9A).

Measurements (in µm)

Ƌ: RV: L = 985-1007 (n= 2), H = 572-597 (n= 2). LV: L = 1053-1067 (n= 2), H = 604-625 (n= 2). Cp: L = 1010-1082 (n= 4), W = 581-644, H = 600-603. (n= 2).

♀: RV: L = 1099-1150 (n =5), H = 663-706 (n =5). LV: L = 1157-1222 (n =5), H = 685-738 (n =5). Cp: L = 1078-1224 (n =9), W = 613-738 (n =4), H = 724-733 (n= 4).

Other material investigated

Dam near Lake Dunn, north east of Aramac QLD collected by RS and AK on 7 Jun. 2011, coordinates: 22º36’15.7” S - 145º40’21.3” E (Sample QLDP 10A).

Stagnant Channel, near Lake Dunn north east of Aramac QLD collected by RS and AK on 7 Jun. 2011, no ƋƋ were found, coordinates: 22º35’42.3” S - 145º41’58” E (Sample QLDP 8A).

Flooded field, near Lake Dunn north east of Aramac QLD collected by RS and AK on 6 Jun. 2011, no ƋƋ were found, coordinates: 20º36’10.3” S - 145º41’14” E (Sample QLDP 6A).

Pelican Lake, north of Hughenden QLD collected by RS and AK on 9 Jun. 2011, no ƋƋ were found, coordinates: 19º51’53.1” S - 144º15’20” E (Sample QLDP 13B).

Cardenyabba Lagoon, Kilcowera Station, south of Thargomindah QLD collected by AK on 14 Jun. 2011, no ƋƋ were found, coordinates: 28º40’13.2” S - 143º54’10.4” E (Sample QLDP 18A).

These populations were the same Evolutionary Genetic species ( Birky & Barraclough 2009) as the type population, which confirmed morphological evidence that they belong to the same species as the type population.

Differential diagnosis

Bennelongia dedeckkeri sp. nov. belongs to the B. barangaroo lineage, because of its relatively small carapace size (L = 1000 µm), rounded dorsal margin, less pronounced anterior rostrum in dorsal view, less pronounced beak structure of the LV and reduced anteroventral overlapping of LV over RV. It can be distinguished from the other species in this lineage ( B. barangaroo De Deckker, 1981 and B. mckenziei sp. nov.) by the pointed dorsal margin of the second Rpp segment (more rounded in B. barangaroo ), the straight posterodorsal margin (hinge) of the RV (more rounded in B. barangaroo and B. mckenziei sp. nov.), the beak point of the carapace being positioned well above the ventral plane (positioned on the ventral plane in B. barangaroo ) and the presence of an anteroventral and ventrally-pointed lapel on the RV (absent in B. mckenziei sp. nov.).

Additional description

Male and female Cp ( Fig. 4 E-H, K-L) similar in size and appearance with blunt anterior rostrum and blunt posterior side; in lateral view with rounded dorsal margin, LV overlapping RV on all sides, overlap narrow at middle of dorsal margin, greatest height slightly anterior of the middle; external valve surface hirsute with setae approximately 50 µm in length.

Male and female LV ( Fig. 4A, C ) with rounded dorsal margin, greatest height situated slightly in front of the middle; anteroventral beak-like expansion small and blunt, point of beak well above ventral plane; ventral margin straight for approximately half its length; anterior inner list reaching well beyond the middle of the valve.

Male and female RV ( Fig. 4B, D ) with rounded dorsal margin anteriorly but straight posteriorly from the middle onwards (dorsal hinge); greatest height slightly anterior of the middle, outer list of RV with ventral row of tubercles; posterior list submarginal, but merging with selvage at beginning of straight dorsal margin (hinge); selvage at height of lapel expanded, lapel ( Fig. 4I, J ) broad, but running along short length of selvage with light serration sometimes visible.

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

First segment of Rpp ( Fig. 5A ) with rounded ventral margin and nearly straight dorsal margin, elongated, approximately 2 x as long as central width, apically with one long slender sensory organ; second palp segment with margins diverging distally, distally pointed with sensory organ and also pointed on dorsal margin.

First segment of Lpp ( Fig. 5B ) with rounded ventral margin and nearly straight dorsal margin, narrowing distally; elongated, approximately 2 x central width; sub-apically with sensory organ; second palp segment sickle shaped, approximately 0.75 x as long as first segment and sharply curved asymmetrically over 180°, with distal sensory organ.

Hemipenes ( Fig. 5 C-D) with symmetrical outlines, ls protruding well beyond ms, tips of ls and ms well separated, ls distally pointed and ms with pointed ventral lobe.

Ecology and distribution

This species has been found in both permanent and ephemeral wetlands, occurring sympatrically with B. pinpi in Pelican Lake QLD and B. mckenziei sp. nov. in Cardenyabba Lagoon QLD (both species are similar in appearance). Males have been found in only some of these populations, suggesting that the others may be parthenogenetic, particularly in those localities in which other species of Bennelongia occur ( B. pinpi in Pelican Lake and B. mckenziei in Cardenyabba Lagoon ).

Figures

Fig. 4. Bennelongia dedeckkeri sp. nov., all from Lake Galilee, QLD (Type locality). A. ♀, LVi (W40020). B. ♀, RVi (W40019). C. Ƌ, LVi (W40016). D. Holotype Ƌ, RVi (W40075). E. ♀, Cp dorsal (W40025). F. ♀, Cp ventral (W40026). G. Ƌ, Cp (ventral W40023). H. Ƌ, Cp dorsal (W40022). I. Holotype Ƌ, RVi detail anteriorly (W40075). J. Ƌ, RVi detail anteriorly (W40019). K. Ƌ, CpRl (W40021). L. ♀, CpRl (W40024). Scales: A-H, K-L = 500 μm, I-J = 100 μm.

Fig. 5. Bennelongia dedeckkeri sp. nov. (A = W40017 & B-D = W40016 Ƌ). A. Right prehensile palp. B. Left prehensile palp. C. Hemipenis showing inner anatomy. D. Outline of other hemipenis. Scales: A-B = 30.9 μm, C-D = 89.3 μm.