Xestoleberis petrosa, Chand, Prerna & Kamiya, Takahiro, 2016

Chand, Prerna & Kamiya, Takahiro, 2016, Seven new species of the genus Xestoleberis (Ostracoda: Podocopida: Cytheroidea) from the Fiji Archipelago, Zootaxa 4208 (4), pp. 325-348 : 340-342

publication ID	https://doi.org/ 10.11646/zootaxa.4208.4.2
publication LSID	lsid:zoobank.org:pub:6D3B4F32-7196-4DF9-B6E5-401FCF4A4CE6
DOI	https://doi.org/10.5281/zenodo.6078113
persistent identifier	https://treatment.plazi.org/id/8B57EE20-FFFB-B31C-B4CC-3DF842578CFF
treatment provided by	Plazi
scientific name	Xestoleberis petrosa
status	sp. nov.

Treatment

Xestoleberis petrosa n. sp.

Type series. Holotype: male UMUT RA32524 ( Figs. 9 View FIGURE 9 A–B’, E–F, J, 2M–N). Paratypes: male—UMUT RA32528 ( Fig. 13 View FIGURE 13 A–B, F1–F2), females—UMUT RA32526 ( Fig. 9 View FIGURE 9 C–D), UMUT RA32527 ( Fig. 9 View FIGURE 9 G–I, K), UMUT RA32529 ( Fig. 13 View FIGURE 13 D–E), UMUT RA32530 ( Fig. 13 View FIGURE 13 C). All type material was collected from the type locality. The holotype and paratypes are deposited at the University Museum , University of Tokyo, Japan . Valves on paleontological paper/cavity slides and soft parts mounted on glass slides. Additional paratypes preserved in 70% ethanol: two males and one female UMUT RA32525.

Type locality. The rocky, open northwest coast of Tavewa Island in the Yasawa Group (P1, Fig. 1 View FIGURE 1 , Table 1); habitat: cushion like green algae ( Dictyosphaeria versluysii ).

Etymology. Petrosa is Latin for rocky. This species was characteristic of algae growing on a rocky headland on the north west of Tavewa Island ( Fig. 1 View FIGURE 1 ).

Diagnosis. Posterior end of carapace more widely rounded than anterior end. Carapace dorsoventrally flattened, coloration in living animals translucent, smooth and dotted with pores. Prominent ventral indentation two fifths of way from anterior. BO short segment with five terminating setae. Ejaculatory duct appears as two stacked layers separated by a single loop. Furca reduced to a short seta.

Description. Carapace reniform, inflated and elongated ( Figs. 2 View FIGURE 2 M–N, 13A–F2). Maximum valve length range: 328 µm–377 µm, maximum valve height range: 104 µm–165 µm ( Table 2). Maximum height at mid-length. Dorsal margin convex, ventral margin with conspicuous indentation. Wide anterior and narrow posterior vestibula. Merodont hinge. Carapace surface scattered with normal sieve pores. Normal simple pores concentrated on anterior and antero-ventral edges of valve. Scar pattern; topmost scar of posterior row of four adductor scars, trefoil and single anterior scar U-shaped.

An1 with six podomeres; first two big and elongated, third–sixth small and quadrate ( Fig. 9 View FIGURE 9 A–A’). Second, third and fourth podomeres with one dorsal apical seta each, two dorsal apical setae on fifth podomere, sixth podomere with three fine and one slender, round-tipped terminating setae. An2 with one dorsal apical seta on first endopodite podomere, one dorsal and ventral medial seta and one ventral apical seta of second endopodite podomere ( Fig. 9 View FIGURE 9 B–B’). Pectinate terminating claws. Md coxa with six pointed teeth and two fine setae ( Fig. 9 View FIGURE 9 C– D). Palp with four podomeres: one dorsal and two ventral apical setae on second podomere, three medial setae at junction of second and third podomeres, two dorsal, two ventral medial setae and one ventral apical seta on third podomere, two medial setae at junction of third and fourth podomere and three stout terminating setae of fourth podomere. Mx with two segmented palp; first segment with three distal dorsal-apical setae and second segment with four terminating setae ( Fig. 8 View FIGURE 8 E–E’). Branchial plate with 12–14 setuled setae. BO symmetrical short segment with five terminating setae ( Fig. 8 View FIGURE 8 F).

Basal setal formula for L5 1:2:1 and L6 and L7 1:1:1 ( Fig. 8 View FIGURE 8 G–I). Terminating claws of thoracic legs: L5 and L6 curved, L7 straight. Hp with asymmetrical triangular distal processes; one with sharply pointed tip, other with rounded tip ( Fig. 8 View FIGURE 8 J). Proximal ends of capsules sub-rounded and proximal support structure T-shaped. Furca, short fine setae on round base.

Distribution. Out of the eight locations sampled for ostracods across Fiji, X. petrosa n. sp. was only collected at one site (type locality above). Specimens of X. petrosa n. sp. were also collected from a short red alga inhabiting the same rocky substrate as Dictyosphaeria versluysii (holotype habitat) and a bluegreen alga.

Remarks. Carapace appearance and size of Xestoleberis petrosa n. sp. is similar to Xestoleberis planuventer Sato & Kamiya, 2007 ( Fig. 13 View FIGURE 13 Sato & Kamiya 2007) reported from Okinawa, Japan. However, the soft part morphologies of both species differ. X. planuventer —hirsute An2 and leg (L5, L6, L7) setae, crown of setae on the base of L6 and L7 claw and tip of L7 is serrated. These features are absent in X. petrosa n. sp. In addition, the ejaculatory duct arrangement, the shape of the distal processes and the proximal structure of the Hp of both species are different.