Leicacandona pinkajartinyi, Karanovic & McKay, 2010

Karanovic, Ivana & McKay, K., 2010, Two new species of Leicacandona Karanovic (Ostracoda, Candoninae) from the Great Sandy Desert, Australia, Journal of Natural History 44 (45 - 46), pp. 2715-2736 : 2721-2727

Leicacandona pinkajartinyi sp. nov.

( Figures 3A, B, E, F ; 4B, D, E ; 5A, C, D, F ; 6B, D ; 7A, B )

Material examined

Holotype Ƌ (dissected on one slide WAM C35720), and two paratype ♀ s (in alcohol, WAM C35721) from: Australia, Western Australia, Great Sandy Dessert , Telfer Gold Mine, HB 54, 12 August 2008, 21°43′40.8″S 122°12′20.5704″E.

Diagnosis

Greatest height of carapace behind middle; A1 five-segmented; Md-palp with one seta dorsally on first segment; male prehensile palps almost symmetrical; T2 five-segmented; distal seta on penultimate segment very long; all basal setae on T3 present; penultimate segment divided; posterior claw on CR reduced.

Etymology

The species is named after a mollusc found in the area where it was collected. It is a word of Pitjakali language, a dialect of Nyangumarta which is the lingua franca of the Indigenous People of this region.

Description

Male. L = 0.34 mm. Greatest height (H) situated behind mid-L, equalling 53% of L. Dorsal margin arched at the point of greatest H, sloping down gradually towards anterior margin and being rounded towards posterior margin ( Figure 3F ). Anterior margin broadly

Note: Scale bar = 0.1 mm; z1 and z2, setae; G1–3 and Gm, claws; Y, aesthetasc. rounded, posterior margin gently rounded, almost straight. Ventral margin only slightly concave around mouth region. Inner calcified lamella fairly broad on both ends, anteriorly equalling 21% of L, posteriorly equalling 18% of L. Marginal pore canals very short, straight and dense. Surface of valve with sparse setae and transparent.

A1 ( Figure 4B ). Five-segmented. First segment with only one anterior seta (proximal one) and two posterior setae. Second segment with one anterior seta being same length (L) as anterior margin of same segment. Third segment representing fused ancestral segments 3 and 4 and carrying two distal setae, both very short, one positioned anteriorly, other posteriorly. Fourth segment representing fused ancestral segments 5 and 6 and carrying distally three long setae. Terminal segment free and with three long setae and most posterior one short. Aesthetasc ya ( Figure 4E ) conspicuously long. L ratios of last three segments 1.9:1.46:1.

A2 ( Figure 4D ). Exopod consisting of three equally long, short setae. Endopod three-segmented. First segment ventrally with one aesthetasc (Y) located medially, and exceeding distal end of same segment. First segment with one ventro-distal seta reaching middle of terminal claws. Second endopodal segment without medio-dorsal setae and with only one medio-ventral seta observed, reaching middle of terminal claws. Setae z1 and z2 transformed into long claws as long as first endopodal segment. Claw G2 as long as z-setae. Claw G1 reduced, and being less than half as long as G2. Claw G3 reduced into thin seta, only slightly exceeding terminal segment. Claw Gm on terminal segment long, as long as first endopodal segment. Claw GM reduced. Length ratios of endopodal segment equalling 11.5:5.5:1.

Md ( Figure 5D ). Branchial plate with five to six setae. First segment internally with three setae. Second segment of palp dorsally with one seta almost reaching distal margin of penultimate segment. Same segment ventrally with three + two setae in the bunch, one of the shortest setae representing β- seta. Following segment with two long, dorsal setae exceeding middle of terminal claw. Same segment with two ventrodistal seta (one long one short) and one medio-distal seta representing γ- seta. Terminal segment short, with central claw fused with segment, and one dorsal and one ventral seta.

Mxl-palp ( Figure 3B ). Two-segmented. First segment with three setae, terminal segment with three claw-like setae. All setae equally long.

Rake-like organ ( Figure 5E ). With 10–11 teeth.

Prehensile palps ( Figures 3E , 5A ). Palps almost symmetrical, both with prominent, long body and hook-like fingers. Finger on right palp being slightly shorter and more hook-like than on the left palp.

T2 ( Figure 6D ). Basal segment without seta. First endopodal segment without seta. Second and third endopodal segments completely divided. Second with one seta reaching distal end of penultimate segment, third with very long seta reaching middle of terminal claw. Terminal segment with one distal seta twice as long as same segment. Terminal claw heavily serrated and as long as L of three distal segments combined.

T3 ( Figure 5C ). Basal segment with all three setae present. First endopodal segment without any seta. Second and third segments subdivided, second without any seta, third with short “g” seta. Terminal segment with h1, h2 and h3 setae. Length ratios of three setae: 1:2:16.

CR ( Figure 6B ). Ramus short and stout. Anterior seta not present, posterior seta short not reaching distal margin, and being inserted close to the distal end of posterior margin. Posterior claw reduced and being half as long as anterior claw. Anterior claw longer than anterior margin of ramus.

Hemipenis ( Figure 3A ). Lobe a triangular and narrow, lobe b also subtriangular with almost flat distal margin. Border between lobes not clearly visible. Lobe h not observed.

Zenker organ ( Figure 7B ). With four + two whorls of spines. Only juvenile females ( Figure 7A ) collected.

Affinities

Leicacandona pinkajartinyi sp. nov. is a typical representative of the genus, having a short and stout CR and only six rows of spines on the Zenker organ. It has a similar carapace shape to L. mookae Karanovic, 2007 , but in the new species the greatest H is moved more towards the posterior end. Other characters are similar to most Leicacandona species , except L. macra which has a linear, but weak valve ornamentation. Together with L. jimi Karanovic, 2007 , L. lite Karanovic, 2007 , L. quasihalsei Karanovic, 2007 , L. yandagoogeae Karanovic, 2007 , and L. jula sp. nov., the new species has a reduced posterior claw on the CR. In the other species of the genus this claw is fully developed and only slightly shorter than the anterior one. The new species also differs from L. jimi by the absence of a postero-dorsal keel-like growth on the carapace. The two species also differ from L. jimi in the appearance of T3, which is four-segmented. Leicacandona lite has a fused second and third endopodal segment of T3 and a four-segmented T2. From L. quasihalsei the new species differs by a long distal seta on the penultimate segment of T2. In addition, the appearance of the hemipenis is quite different, as L. quasihalsei has a very “high” lobe “a”, while this lobe is almost at the same level as lobe “b” in the new species. Leicacandona quasihalsei also lacks the d2 seta on the basal segment of T3. Leicacandona yandagoogeae is easily distinguished from the new species by four-segmented legs T2 and T3 and the presence of two short setae dorsally on the first segment of the Md-palp. Unfortunately, L. yandagoogeae is described only from a female. The second new species described in this paper, L. jula , differs from L. pinkajartinyi by four-segmented T2 and T3 legs, a different hemipenis appearance and an unusually short third segment of A1.

Figures

Figure 3. (A, B, E, F) Leicacandona pinkajartinyi sp. nov. (holotype); (C, D) L. jula sp. nov. (holotype); (A, D) hemipenis; (B) maxillula-palp; (C) left prehensile palp; (E) right prehensile palps; (F) right valve, internal view. Notes: Scale bars = 0.1 mm; a, b, e and g, lobes.

Figure 4. (A, C) Leicacandona jula sp. nov. (holotype); (B, D, E) L. pinkajartinyi sp. nov. (holotype). (A) antennula (A1) (without setae on the terminal segment); (B) A1 (figure doesn’t show basal segment and setae on the terminal segment); (C, D) antenna; (E) aesthetasc ya.

Figure 5. (A, C–E) Leicacandona pinkajartinyi sp. nov. (holotype); (B) L. jula sp. nov. (holotype). (A) right prehensile palp; (B) distal part of third thoracopod (T3); (C) T3; (D) mandibula-palp; (E) rake-like organ. Notes: Scale bar = 0.1 mm; d1–3, h1–3 and g, setae.

Figure 6. (A, C, E) Leicacandona jula sp. nov. (holotype); (B, D) L. pinkajartinyi sp. nov. (holotype); (A, B) caudal ramus (CR); (C) distal part of second thoracopod (T2); (D) T2; (E) attachment of CR. Note: Scale bar = 0.1 mm.

Figure 7. (A) Leicacandona pinkajartinyi sp. nov. (paratype): juvenile, lateral view; (B) L. pinkajartinyi sp. nov. (holotype): Zenker organ; (C–E) L. jula sp. nov. (holotype); (C) left valve, internal view; (D) antenna; (E) Zenker organ.