Ozestheria rincewindi, Schwentner & Hethke, 2025

Schwentner, Martin & Hethke, Manja, 2025, Revision of the Australian Ozestheria Schwentner & Richter, 2015 (Crustacea: Branchiopoda: Spinicaudata) fauna, with the descriptions of 27 new species, European Journal of Taxonomy 992, pp. 1-172 : 124-126

Ozestheria rincewindi sp. nov.

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Fig. 39

Ozestheria sp. U – Schwentner et al. 2015 a: figs 2, 6; 2020: figs 1–2.

Diagnosis

Ozestheria rincewindi sp. nov. is characterized by a long condyle and a narrow occipital notch; carapace length of 5.0 mm; carapace ornamentation dorsally on carapace punctate (may appear granular), in following growth bands anastomosing lirae forming ventrally within growth band, lirae become longer, less anastomosing and more pronounced within progressing growth bands; male rostrum with convex anterior margin, apex rounded with acute angle (close to 90°), ventral margin straight; 16 (male) antennule lobes reaching to antennal flagellomeres VIII (male); 10 (male) antennal flagellomeres; 20 complete thorax segments; 20 telsonic spines, anterior spines conical with two larger spines interspersed, posterior spines elongated and aciculate, increasing in size posteriorly; 8 furcal setae.

Differential diagnosis

Ozestheria rincewindi sp. nov. can be differentiated from many other species of Ozestheria by the narrow occipital notch and long condyle in combination with the carapace ornamentation (dominated by punctate ornamentation dorsally on carapace, transitioning to distinct, subparallel lirae during ontogeny), except from O. cancellata comb. nov., O. minor comb. nov., O. typica comb. nov., O. fuersichi sp. nov., O. marthae sp. nov., O. selmae sp. nov., O. radiata sp. nov., O. bourkensis sp. nov., O. jonnae sp. nov., O. barcaldinensis sp. nov., O. ngamurru sp. nov., O. beleriandensis sp. nov., O. quinlanae sp. nov., O. glabra sp. nov., O. pilbarensis sp. nov. and O. weeksi sp. nov., and differentiating these species can be difficult. Ozestheria minor , O. typica , O. bourkensis , O. selmae , O. radiata , and O. beleriandensis can be differentiated by having at least the posterior half of the telsonic spines long, elongated and aciculate and O. fuersichi by its polygonal reticulations on the first few growth bands and punctae between widely spaced lirae. The naupliar eye of O. rincewindi sp. nov. is situated more dorsally within the rostrum than in any other species of Ozestheria (where the naupliar eye is usually situated near the central part of the rostrum). In contrast to O. cancellata , O. fuersichi sp. nov., O. marthae , O. jonnae , O. ngamurru and O. glabra the ocular tubercle is well developed in males of O. rincewindi . Ozestheria rincewindi differs from O. barcaldinensis by having a straight (vs concave) margin between condyle and ocular tubercle and a more acute apex at the male rostrum.

Etymology

The species is named after Rincewind, a fictional character in the books by Terry Pratchett, who visited Discworld’s equivalent of Australia.

Type material

Holotype

AUSTRALIA – South Australia • ♂; dugout Wentworth Road ; 33°53′03.4″ S, 140°58′39.1″ E; 13 Mar. 2011; M. Schwentner and B.V. Timms leg.; GenBank no: KJ706082 ; AM P.91857.

Type locality

South Australia, dugout Wentworth Road, 33°53′03.4″ S, 140°58′39.1″ E.

Description

Male (holotype)

CARAPACE ( Fig. 39a–d). Length 5.0 mm, height 3. 0 mm. Lightly brown colored, dorsally slightly darker (slightly reddish-brown). 25 growth lines, 18 widely spaced and seven crowded.

CARAPACE SHAPE. Dorsal margin straight, distinct dorso-posterior corner. Posterior margin broadly rounded, equicurvate (b/H 0.54). Ventral margin broadly rounded, middle section relatively straight. Umbo position submedian (Cr/L 0.26).

CARAPACE ORNAMENTATION ( Fig. 39d–f). Larval valve finely reticulated, dorsal growth bands punctate (may appear granular). From mid-dorsal carapace, growth bands with subparallel, anastomosing lirae forming ventrally within growth bands, which become progressively more pronounced and less anastomosing in later ontogenetic stages (under SEM dense, fine punctae between lirae visible). Ventral and crowded growth bands with short, distinct lirae which terminate in nodules in moniliform row on concentric ridges (more pronounced posteriorly; nodule mainly visible under SEM). Concentric ridges only slightly raised. Setae spiniform (very few present), setae (pores) in single row along all concentric ridges (visible under SEM).

HEAD ( Fig. 39g). Condyle long, distally acute; occipital notch narrow. Condyle with anterobasal hump. Margin between condyle and ocular tubercle straight. Ocular tubercle well developed, forming obtuse angle with rostrum. Anterior margin of rostrum convex, ventral margin straight; apex rounded, acute (close to 90°). Naupliar eye triangular. Antenna I with 16 lobes, reaching to antenna II flagellomere VII. Antenna II anterior ramus with ten flagellomeres.

THORAX. 21 segments, 20 thoracopod-bearing and one posterior limbless segment not reaching dorsal margin. Last 14 thoracopod-bearing segments with dorsal extensions bearing spines. Dorsal extensions increasing in size posteriorly over successive segments, most developed in last nine segments. Spines thin and elongate, stronger and broader in posterior segments.

THORACOPOD III ( Fig. 39h). Endite I short and curved dorsally. Endites II–V broad, decreasing in size. Endite V palp two-segmented, basal segment shorter than endopod. Exopod ventral extension subequal in extension to endopod, dorsal extension wide, narrowing distally. Epipod damaged.

TELSON ( Fig. 39i). 20 spines. First spine (anterior) enlarged. Following nine spines short with one larger spine interspersed, followed by two sets of spines with increasing sizes. Spines slender, elongate, aciculate. Last spines extend beyond base of terminal claw. Terminal claw slightly curved, more strongly curved on right body half (tips broken off). Anterior ⅔ of dorsal margin nearly straight, posterior third concavely curved.

FURCA ( Fig. 39i). Proximally with dorsomedial longitudinal row of eight setae, row ending distally in a single conical spine. Distal part ⅔ of furca length, with numerous small denticles.

Females

Unknown.

Distribution

Currently known only from its type locality in eastern South Australia.

Remarks

Only a single male specimen is known. The carapace shape of Ozestheria rincewindi sp. nov. ( Fig. 6) is distinct from most other species and overlaps with that of O. jiangi sp. nov., O. minor comb. nov. and O. echidna sp. nov.