Hancockcandonopsis, Karanovic, 2018

Karanovic, Ivana, 2018, A new Candonopsini (Ostracoda) genus from subterranean waters of New South Wales (Australia), Zootaxa 4379 (2), pp. 247-267 : 254-256

Hancockcandonopsis io sp. nov.

Figures 5–6

Type locality: Bore 93024, Peel River alluvial aquifer, Dungowan Creek Alluvium , Tamworth, New South Wales, 151°09’E 31°14’S, 09/12/2005, collector Peter Hancock.

Material Examined. Holotype: male dissected on one slide (P. 100299); Paratypes: one male and one disintegrated female on SEM stub, all from the type locality.

Etymology: Greek “ Io ”—daughter of Inachos.

Differential diagnosis. Carapace subtriangular in lateral view, surface smooth; A1 7-segmented; second segment of male A2 subdivided; prehensile palps symmetrical and with strongly sclerotized bases of subterminal cuticular structures; d1-seta on L6 present; f-seta present on both L6 and L7; hemipenis with distal projection of alobe, both rounded, b-lobe distally flat.

Description of male. Carapace subtriangular in lateral view ( Figures 5E, F , 6A ), with highly arched dorsal margin. Anterior and posterior margins rounded, posterior being narrower than anterior one. LV overlaps RV dorsally with pronounced flange; RV with flattened dorsal margin. Ventral margin slightly concave. Shell surface smooth and covered with long and dense sensilla, exiting from pores with lip margin. Anterior calcified inner lamella wider than posterior one. Marginal pore canals short and unbranched. Maximum L around 0.85 mm. Greatest H situated medially, equaling 55% of total L.

A1 ( Figure 6B, C ) 7-segmented. First segment with two anterior and two posterior setae. Second segment with one short anterior seta. Third and fourth segments with one short anterior and posterior seta each. Fifth segment with one long and one short seta; sixth segment with one long and 3 short setae. Terminal segment ( Figure 6C ) with two long, one short seta and aesthetasc, which about 2.5 times longer than terminal segment. L ratios between 5 distal segments equaling 1: 1: 1: 1.2: 1.1.

A2 ( Figure 6E ) 6-segmented with 2-segmented protopodite and 4-segmented endopodite. Exopod with one long and two short setae. Aesthetasc Y not exceeding distal margin of second endopodal segment. First endopodal segment with two setae postero-distally. Penultimate segment divided with male sexual bristles. z2-seta transformed into long claw, z1-seta shorter but also claw-like. G1- and G3-claws reduced, G2-claw long. Gm-claw long, GM-claw short.

Md-palp ( Figure 6H ) with short terminal segment (as wide as long). First segment anteriorly without any seta, posteriorly with two S-setae (S1 plumose and long; S2 pappose and short). Second segment with two anterior setae (one considerably longer than the other), posteriorly with three setae in the bunch, plus β-seta, and one additional pappose seta. Penultimate segment with three long setae anteriorly, smooth γ-seta and one smooth seta next to it, and four setae posteriorly, one of which longer and stouter than the other three. Terminal segment with broadly fused central claw, one addition claw to its anterior side, and two setae to its posterior side.

Rake-like organ ( Figure 6D ) with approximately 10 small teeth.

Prehensile palps ( Figure 6F, G ) almost symmetrical, both with elongated bodies and long, barely curved fingers. Both subapical cuticular structures long and one always stronger and more sclerotized than other.

L6 ( Figure 6I, J ) 5-segmented. Basal seta (d1) present. First and second endopodal segments with one short seta each. Third segment with two small distal setae. Terminal segment with two setae and one long claw.

L7 ( Figure 6K ) 5-segmented. Basal segment with all three setae (d1, d2, dp). Endopodal segments with e-, f-, and g-setae. Terminal segment with three setae, h3-seta longest and hook-like distally, followed by h2- and h1-seta. UR ( Figure 6M ). UR without posterior seta, anterior seta very short. L ratios between anterior margin, anterior claw, and posterior claw 1.7: 1.2: 1.

Hemipenis ( Figure 6L ) robust. a-lobe with distal projection only, rounded. b-lobe distally flat, rounded outer, and rectangular inner margin. Ejaculatory process distally worm-like.

Zenker-organ with 5+2 whorls of spines.

Description of female. Carapace ( Figures 5A–F ) higher than in male (greatest H 62% of L). Surface same as in male ( Figure 5C, D ). L same as male.

Both females had disintegrated soft parts.

Figures

FIGURE 6. Line drawings of Hancockcandonopsis io gen. nov., sp. nov. Male (P.100299): A—whole carapace; B, C—A1 (first segment on B not illustrated, not all setaeillustrated on C); D, Rake-likeorgan; E—A2; F—right prehensile palp, G—left prehensile palp; H—Md-palp; I—L6; J—basal segment of L6; K—L7; L—hemipenis; M—UR.Scales = 0.1 mm.

FIGURE5. SEM of Hancockcandonopsis iogen. nov., sp. nov. A–D, female; E–I, male:A—whole carapace viewed from the right side; B—detail of the dorsal margin; C—surface cuticular pore with seta; D—detail of the surface; E—LV, viewed from the outside; F—RV,viewed from the outside.