Ozestheria radiata, 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 : 117-120

Ozestheria radiata sp. nov.

urn:lsid:zoobank.org:act:13C3B4FB-34FF-4DEE-A553-F846124D3BBA

Fig. 37

Ozestheria sp. Q4 – Schwentner et al. 2015a: figs 2, 6.

Diagnosis

Ozestheria radiata sp. nov. is characterized by a long condyle and a narrow occipital notch; carapace ornamentation dorsally on carapace punctate (may appear granular), in following growth bands anastomosing lirae forming ventrally within growth band, lirae become more pronounced with progressing growth bands; male rostrum anterior margin weakly concave, straight or weakly undulating, apex strongly rounded with ~90° angle, ventral margin weakly convex or straight (with slight notch close to apex); female rostrum anterior margin nearly straight (slightly convex), apex nearly rectangular angle with drawn-out tip, ventral margin slightly concave or slightly convex; 11–14 (male) or 13–14 (female) antenna I lobes reaching to antenna II flagellomeres VI–IX (male) or II–IV (female); 10–12 (male) or 10–11 (female) antenna II flagellomeres; 19–20 complete thorax segments; 15–29 large and densely spaced telsonic spines, spines thin, elongate and aciculate, anteriormost spines slightly broader and shorter, spines increasing in length posteriorly, one slightly larger spine interspersed (at about mid-length of telson); 4–8 furcal setae.

Differential diagnosis

Ozestheria radiata 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. jonnae sp. nov., O. marthae sp. nov., O. bourkensis sp. nov., O. rincewindi 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 radiata differs from O. cancellata , O. fuersichi , O. jonnae , O. marthae , O. rincewindi , O. barcaldinensis , O. ngamurru , O. quinlanae , O. glabra , O. pilbarensis and O. weeksi by having at least the posterior half of the telsonic spines long, elongate and aciculate (in the other species fewer telsonic spines are long and aciculate and more spines are shorter and conical) and by the shape of the male and female rostrum. Ozestheria bourkensis and O. typica have smaller carapaces, the male rostrum of O. bourkensis has a convex anterior margin and the male rostrum of O. typica is less strongly rounded. In O. minor the male rostrum has a pointed (not rounded) apex and the female rostrum apex is drawn out into a larger acute tip. Ozestheria beleriandensis has a more rounded ventral margin of the carapace, less strongly developed ocular tubercles and the male rostrum has a pointed (not rounded) apex. Ozestheria selmae sp. nov. has more complete thorax segments (21–22 vs 20–21), a less strongly rounded male rostrum apex and the female rostrum apex is not as finely pointed.

Etymology

The species name derives from the Latin word ‘ radiatus ’ (‘radiant’), referring to the radial arrangement of the ornamental features on the carapace.

Type material

Holotype

AUSTRALIA – Western Australia • ♂; roadside scrape, 12 km W of Paynes Find ; 29°17′07″ S, 117°34′01″ E; 20 Aug. 2011; B.V. Timms leg.; GenBank no: KJ705934 ( COI); AM P.91706.

Paratype

AUSTRALIA – Western Australia • 1 ♀; same data as for holotype; GenBank no: KJ705935 ( COI); AM P.91707 .

Other material examined

AUSTRALIA – Western Australia • 2 ♂♂; Pool Pianto Road, Goongarrie National Park ; 29°54′53.7″ S, 121°21′2.7″ E; 22 Feb. 2017; K. Quinlan leg.; WAM C78001 , C80190 • 4 ♂♂, 1 ♀; Pool South of Lake Ballard ; 29°27′31.9″ S, 120°36′51.4″ E; 21 Feb. 2017; K. Quinlan leg.; WAM C78004 , C80191 to C80193 • 3 ♂♂; Silvers Lake , 8 km West of Lake Goongarrie; 29°59′42.7″ S, 121°3′54.1″ E; 22 Feb. 2017; K. Quinlan leg.; WAM C78005 , C80195 to C80197 • 2 ♂♂; Silvers Lake , 8 km W of Lake Goongarrie; 29°59′42.7″ S, 121°3′54.1″ E; 22 Feb. 2017; K. Quinlan leg.; NHMW-ZOO-CR-28493, NHMW-ZOO-CR-28494 .

Type locality

Western Australia, roadside scrape, 12 km W of Paynes Find, 29°17′07″ S, 117°34′01″ E.

Description

Male

CARAPACE ( Fig. 37a, c–d). Length 3.5–5.7 mm (HT: 5.7 mm, mean: 4.3 mm), height 2.0– 3.4 mm (HT: 3.4 mm, mean: 2.5 mm). Coloration ranging from light orange to yellowish-orange, outer margin lighter. 24–31 (HT: 31, mean: 27) growth lines, 11–17 (HT: 17, mean: 15) widely spaced and 9–15 (HT: 14, mean: 12) crowded.

CARAPACE SHAPE. Dorsal margin straight, distinct dorso-posterior corner. Posterior margin broadly rounded, equicurvate (b/H 0.49–0.55, HT: 0.49, mean: 0.53). Ventral margin nearly straight in middle section. Umbo position anterior to submedian (Cr/L 0.27–0.32, HT: 0.27; mean: 0.29).

CARAPACE ORNAMENTATION ( Fig. 37e–g). Larval valve and directly following growth bands finely punctate to finely reticulated (may appear granular; punctae best seen under SEM). Within following growth bands (about mid carapace), dorsal parts punctate, with shallow and strongly anastomosing lirae forming between punctae ventrally within growth bands (the onset and extent of lirae differs markedly between individuals). Lirae becoming more pronounced in progressing ontogenetic stages. Crowded growth bands with well-defined parallel short lirae forming deep pits. Concentric ridges shallow, with nodules at the upper margin in moniliform row in later ontogenetic stages. Setae mostly spiniform; preferentially preserved on ventral and posterior parts of the carapace, if any preserved. Setal pores in single row along all growth lines.

HEAD ( Fig. 37h). Condyle long, distally acute; occipital notch narrow. Condyle with anterobasal hump. Margin between condyle and ocular tubercle straight to concave (HT: weakly concave). Ocular tubercle weakly to well developed, forming rectangular or obtuse angle with rostrum, which varies from ~90–160° (HT: ~90°). In some individuals rostrum dorsally protruding from head. Anterior margin of rostrum weakly concave (sometimes nearly straight) or undulating (dorsally concave, ventrally convex; HT: undulating). Ventral margin of rostrum with slight notch close to apex, posteriorly weakly convex or straight; apex strongly rounded, ~90°. Naupliar eye subtriangular or roundish. Antenna I long with 11–14 lobes (HT: 13), reaching to antenna II flagellomeres VI–IX (HT: VI). Antenna II with 10–12 flagellomeres (HT: 12, mean: 11).

THORAX. 20–21 (HT: 21, mean: 20) segments, 19–20 (HT: 20, mean: 19) thoracopod-bearing and one posterior limbless segment not reaching dorsal margin. Last ~13 thoracopod-bearing segments with spine bearing dorsal extensions.

THORACOPOD III (only P.91706; Fig. 37k). Endite I short and curved dorsally. Endites II–V broad, decreasing in size. Endite V palp two-segmented, basal segment extending further than endopod. Exopod ventral extension shorter in extension to endopod, dorsal extension wide, narrowing distally, overreaching epipod. Epipod long, cylindric.

TELSON ( Fig. 37j). 21–29 spines (HT: 28; mean: 24). First (anterior) spine greatly enlarged. Following spines subequal in length, thin, elongate, aciculate (anterior ⅓ to ½ of spines slightly broader, shorter and slightly conical); posterior spines increasing in size; all spines very densely spaced; 1 slightly larger spine interspersed (about mid-length of telson). Dorsal margin slightly concave. Right terminal claw more strongly curved than left.

FURCA ( Fig. 37j). Proximally with dorsomedial longitudinal row of 4–8 (HT: 7, mean: 6) setae, row ending distally in a single conical spine. Distal part ⅔ of furcal length, with numerous small denticles.

Females

Overall appearance as in males. Carapace ( Fig. 37b) length 3.8–5.2 mm, height 2.3–3.0 mm; 20–22 growth lines, 16–17 widely spaced and 3–6 crowded; Cr/L 0.28–0.29 and b/H 0.53–0.54. Ocular tubercle forming obtuse (~140–180°) angle with rostrum ( Fig. 37i). Rostrum protruding dorsally in some individuals; anterior margin nearly straight (slightly convex); apex pointed, nearly rectangular angle, tip drawn out; ventral margin with slight notch close to apex, slightly concave or slightly convex; overall rostrum shape trapezoidal. Antenna I with 13–14 small lobes, lobes smaller than in males, often poorly separated from each other; reaching to antenna II flagellomeres II–IV. Antenna II with 10–11 flagellomeres. Telson with 15–23 dorsal spines; left and right terminal claws equally curved. Furca with 6 setae, distal part ⅔ of furcal length.

Distribution ( Fig. 37l)

Ozestheria radiata sp. nov. occurs in southwestern Western Australia.

Remarks

Ozestheria radiata sp. nov. is part of a group of five very closely related species; see remarks on O. typica comb. nov. for details. The carapace shape of O. radiata ( Fig. 6) is distinct from that of most other species and overlaps with those of O. typica and, partly, O. selmae sp. nov., O. bourkensis sp. nov., O. ngamurru sp. nov., and O. beleriandensis sp. nov.