Bennelongia regina, 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 : 17-20

Bennelongia regina sp. nov.

urn:lsid:zoobank.org:act:EC592D84-3E90-4F5A-BB64-9C0CCF5DA2CA

Figs 7-8

Diagnosis

Cp with well-developed anterior rostrum in dorsal view, LV heavily overlapping RV anteroventrally, posteriorly blunt; in lateral view with rounded dorsal margin, LV overlapping RV on all sides. LV with broadly rounded anteroventral beak and rounded dorsal margin. RV with rounded dorsal margin, greatest height situated slightly anterior of the middle, anteroventral lapel broad, serrated and with its distal margin running parallel to selvage. Hemipenes with ls protruding well beyond ms, tips of ls and ms separated; ls distally pointed and ms dorsally with in-fold. Rpp with first segment with rounded ventral margin, long subapical sensory organ and broad second segment. Lpp with proximal segment elongated with nearly parallel margins over two thirds of the segment length, distal segment sickle shaped, much shorter than proximal segment.

Etymology

The Latin “Regina” means Queen; the species has been named as such due to its location within Queensland, but also for its splendour in appearance.

Type material

Holotype

Ƌ (W40060), with soft parts dissected in a sealed slide and valves stored dry in a micropalaeontological slide.

Allotype

♀ (W40074), with carapace stored dry in a micropalaeontological slide.

Paratypes

Three Ƌ carapaces stored in a micropalaeontological slide (W40062-W40064), three ♀ carapaces stored in a micropalaeontological slide (W40065-W40067), ♀ RV and LV (W40061) stored in a micropalaeontological slide.

Several in toto specimens in EtOH (W40077).

Type locality

Horseshoe Lagoon, Kilcowera Station, south of Thargomindah QLD; coordinates: 28º39’57” S - 143º53’42.4” E. Material used for the present description was collected on 16 Jun. 2011 by AK (Sample QLD 21A).

Measurements (in µm)

Ƌ: RV: L = 1381, H = 825. LV: L = 1467, H = 889. Cp: L = 1431-1471 (n =2), W = 852-906.

♀: RV: L = 1667, H = 1012. LV: L = 1769, H = 1079. Cp: L = 1687-1817 (n =2), W = 1002-1102 (n =2), H = 1079.

Other material investigated

The species is thus far known only from its type locality.

Differential diagnosis

Bennelongia regina sp. nov. belongs to the B. nimala lineage because of its hirsute and pustulose valve surface and the large anteroventral overlap of the RV by the LV. It can be distinguished from the other species in this lineage ( B. nimala De Deckker, 1981 ) by the reduced anterodorsal hump-like thickening of the LV in lateral view, the shorter and less abundant setae on the valve surface, the slender ls and the absence of a circular lump shaped copulatory sheath of the hemipenis, the rounded ventral margin of the first Rpp segment, the long subapical sensory organ on the first Rpp segment and the parallel margins of the first Lpp segment.

Additional description

Male and female carapaces in dorsal and ventral view oval shaped with rostrum well-developed, and with large anteroventral overlap of the RV by the LV ( Fig. 7 E-H, K-L); greatest width situated slightly posterior to the middle ( Fig. 7 E-H). Carapace in lateral view with rounded dorsal margin and LV overlapping RV on all sides ( Fig. 7 K-L); greatest height situated near the middle; anterior rostrum (in dorsal view) well-developed, posteriorly bluntly pointed. External valve surface pustulose and hirsute, with setae approximately 50 µm in length. Male valves smaller than female valves, but otherwise similar in appearance.

Male and female LV ( Fig. 7A, C ) with rounded dorsal margin, greatest height situated slightly in front of the middle; anteroventral beak-like expansion large and broadly rounded; ventral margin almost straight over approximately half its length; anterior inner list reaching well beyond the middle of the valve.

Male and female RV ( Fig. 7B, D ) with rounded dorsal margin, greatest height situated slightly anterior of the middle; outer list of right valves with ventral row of tubercles ( Fig. 7B, D ); posterior selvage submarginal, posterior list merging with selvage at dorsal hinge; selvage at height of lapel expanded, striate; lapel ( Fig. 7 I-J) broad, serrated and with distal margin running parallel to selvage.

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

First segment of Rpp ( Fig. 8A ) with rounded ventral margin and straight dorsal margin, elongated, approximately 2 x as long as central width, subapically with one long slender sensory organ, apically with shorter sensory organ, both situated quite far apart; second palp segment sub-triangular, broad and with rounded distal margin; apically with slender sensory organ.

First segment of Lpp ( Fig. 8B ) with parallel margins over two thirds of the length, but narrowing in proximal third, elongated, more than 2.7 x as long as central width, subapically with one long slender sensory organ, apically with shorter sensory organ on elongated outgrowth; second palp segment sickleshaped, approximately 0.75 x as long as first segment and asymmetrically curved over c. 180°, with small distal sensory organ.

Hemipenes ( Fig. 8 C-D) outlines asymmetrical, one hemipenis with ms having two lobes that embrace the ls on inner and outer sides ( Fig. 8D ), one lobe distal and embracing the ls as a three dimensional structure and the other lobe proximal and incomplete. The other hemipenis ( Fig. 8C ) with ms having a single lobe only embracing the ls on the outer side. Both hemipenes with ls protruding well beyond ms, tips of ls and ms well-separated, ls distally pointed ventrally; ms with pointed ventral lobe, dorsally with in-folding of ms.

Ecology and distribution

The species has thus far been found only in its type locality, a turbid temporary freshwater pool with small macrophytes. The species co-existed with another Bennelongia species ( B. mckenziei sp. nov. – assumed to be parthenogenetic) and several macroinvertebrates. No further environmental data are available.

Figures

Fig. 7. Bennelongia regina sp. nov., all from Horseshoe Lagoon, QLD (Type locality). A. ♀, LVi (W40061). B. ♀, RVi (W40061). C. Holotype Ƌ, LVi (W40060). D. Holotype Ƌ, RVi (W40060). E. ♀, Cp dorsal (W40067). F. ♀, Cp ventral (W40066). G. Ƌ, Cp ventral (W40063). H. Ƌ, Cp dorsal (W40062). I. Holotype Ƌ, RVi detail anteriorly (W40060). J. Holotype Ƌ, RVi detail anteriorly (W40060). K. Ƌ, CpRl (W40064). L. Allotype ♀, CpRl (W40074). Scales: A-H, K-L = 1000 μm, J = 200 μm, I = 100 μm.

Fig. 8. Bennelongia regina sp. nov. (all from holotype Ƌ = W40060). A. Right prehensile palp. B. Left prehensile palp. C. Hemipenis. D. Outline of other hemipenis. Scales: A-B = 89.3 μm, C-D = 104.2 μm.