Ozestheria selmae, 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 : 139-143

Ozestheria selmae sp. nov.

urn:lsid:zoobank.org:act:1052560B-D111-4FA3-9C7E-074F1D0B74BF

Fig. 44

Ozestheria sp. Q3 – Schwentner et al. 2015a: figs 2, 6. — Hethke et al. 2023: fig. 11.

Diagnosis

Ozestheria selmae 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 longer, more pronounced and less anastomosing with progressing growth bands; male rostrum anterior margin weakly convex or straight (in some individuals dorsally with a slight concave notch), apex rounded or slightly pointed with ~60–90° angle, usually rounded, ventral margin weakly concave (with or without slight notch close to apex); female rostrum anterior margin slightly concave and undulating, apex nearly rectangular angle with drawn-out tip, ventral margin slightly concave; 10–15 (male) or 8–13 (female) antenna I lobes reaching to antenna II flagellomeres VI–VIII (male) or III–VI (female); 10–14 (male) or 9–12 (female) antenna II flagellomeres; 20–22 complete thorax segments; 15–37 large and densely spaced telsonic spines, first anterior spines slightly broader and conical, all other spines thin, elongate and aciculate, 1 (rarely 2) slightly larger spines interspersed (about mid-length of telson); 2–8 furcal setae.

Differential diagnosis

Ozestheria selmae 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. radiata 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 selmae 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 shorter and conical) and by the shape of the male and female rostrum. Ozestheria bourkensis and O. typica have smaller carapaces and the apex of the female rostrum is drawn out into a smaller (minute) point. Ozestheria minor yields a straight (vs weakly convex) anterior margin of male rostrum, which always lacks the dorsal concave notch. Ozestheria beleriandensis usually has fewer complete thorax segments (19–20 vs 20–22) and the anterior margin of the female rostrum is less concave (nearly straight). Ozestheria radiata has fewer thorax segments (20–21 vs 21–22), a more strongly rounded male rostrum apex and a more finely pointed apex of the female rostrum.

Etymology

The species is named after Selma Hethke-Pott, the daughter of MH.

Type material

Holotype

AUSTRALIA – South Australia • ♂; dead shrub dam 1 km N of William Creek ; 28°54′14.0″ S, 136°19′35.4″ E; 12 Mar. 2011; M. Schwentner and B.V. Timms leg.; GenBank no: KJ705945 ( COI); AM P.91717.

Paratypes

AUSTRALIA – South Australia • 1 ♂, 1 ♀; same data as for holotype; GenBank nos: KJ705942, KJ705944 ( COI); AM P.91714, P.91716 • 1 ♀; same data as for holotype; GenBank no: KJ705943 ( COI); NHMW-ZOO-CR-28486 .

Other material examined

AUSTRALIA – New South Wales • 2 ♂♂, 1 ♀; Barnato Lake ; 31°36′45.2″ S, 144°59′20.0″ E; 22 Jan. 2010; M. Schwentner and B.V. Timms leg.; raised later from sediment; AM P.91688 to P.91690 • 2 ♂♂, 1 ♀; lake next to homestead at Barnato Station , 80 km W of Cobar; 31°36′52.4″ S, 144°52′12.6″ E; 29 Mar. 2010; raised later from sediment; M. Schwentner and B.V. Timms leg.; raised later from sediment; AM P.91680, P.91685 to P.91687 • 3 ♂♂, 1 ♀; Bloodwood Station, Roszkos Paleolake ; 29°27′42.9″ S, 144°48′12.5″ E; 19 Feb. 2010; M. Schwentner and B.V. Timms leg.; AM P.91691 to P.91694 . – Northern Territory • 1 ♂; S of Henbury Crater ; 24°34′22.7″ S, 133°08′53.4″ E; 29 Feb. 2010; M. Schwentner, C. Sieves and B.V. Timms leg.; raised later from sediment; AM P.91704 • 1 ♂, 1 ♀; grassy Ilparpa claypan near Alice Springs ; 23°45′17.1″ S, 133°48′00.0″ E; 8 Mar. 2011; M. Schwentner and B.V. Timms leg.; AM P.91731, P.91732 . – South Australia • 2 ♀♀; borrow pit 90 km S of border; 26°49′22.0″ S, 133°19′44.7″ E; 10 Mar. 2011; M. Schwentner and B.V. Timms leg.; AM P.91735, P.91736 • 4 ♂♂, 1 ♀; clearwater dugout 20 km S of Williams Creek ; 29°05′34.5″ S, 136°32′15.1″ E; 12 Mar. 2011; M. Schwentner and B.V. Timms leg.; AM P.91709 to P.91713 . – Western Australia • 1 ♂; Woomberna Rock on Balladonia Station ; 32°17′01.7″ S, 123°33′22.9″ E; 14 Aug. 2009; B.V. Timms leg.; AM P.91704 .

Additional material (not examined)

AUSTRALIA – South Australia • 1 ♀; vegetated clear water swamp 43 km W of Oodnadatta ; 27°20′38.9″ S, 135°08′40.3″ E; 11 Mar. 2011; M. Schwentner and B.V. Timms leg.; AM P.91733 .

Type locality

South Australia, dead shrub dam 1 km N of William Creek, 28°54′14.0″ S, 136°19′35.4″ E.

Description

Males

CARAPACE ( Fig. 44a, c–d). Length 4.1–6.7 mm (HT: 5.6 mm, mean: 5.5 mm), height 2.4–3.9 mm (HT: 3.4 mm, mean: 3.3 mm). Coloration ranging from reddish-orange to light orange or light whitish yellow (most specimens with light coloration), outer margin lighter. 14–36 (HT: 32, mean: 28) growth lines, 11–25 (HT: 22, mean: 19) widely spaced and 2–15 (HT: 10, mean: 8) crowded.

CARAPACE SHAPE. Dorsal margin straight, distinct dorso-posterior corner. Posterior margin broadly rounded, suboval, equicurvate (b/H 0.48–0.55, HT: 0.57, mean: 0.52). Ventral margin nearly straight in middle section. Umbo position anterior to submedian (Cr/L 0.23–0.29, HT: 0.26; mean: 0.26).

CARAPACE ORNAMENTATION ( Fig. 44e–h). Larval valve and directly following growth bands finely punctate (may appear granular; punctae best seen under SEM). Within following growth bands, dorsal parts punctate, with shallow and strongly anastomosing lirae forming ventrally within growth band (the onset and extent of lirae differs markedly between individuals; in some individuals lirae appear to reach across full growth bands also dorsally on carapace). Lirae becoming more pronounced in progressing ontogenetic stages and posteriorly. From mid-dorsal carapace, lirae pronounced and less strongly anastomosing (especially posteriorly on carapace). Crowded growth bands often too closely set for ornamentation, otherwise well defined, parallel lirae forming forming deep pits. Concentric ridges slightly raised, with nodules at the upper margin in moniliform row in later ontogenetic stages. Setae mostly filiform (rarely 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. 44i–j). Condyle long, distally acute; occipital notch narrow. Condyle with weakly developed or absent anterobasal hump (HT: absent). Margin between condyle and ocular tubercle straight to weakly concave. Ocular tubercle weakly developed, forming obtuse angle with rostrum, which can be nearly straight or close to rectangular (ranging from ~100–170°). In some individuals, rostrum dorsally protruding from head.Anterior margin of rostrum weakly convex or straight, in some individuals dorsally with a slight concave notch. Ventral margin of rostrum with or without slight notch close to apex, posteriorly weakly concave; apex rounded or slightly pointed (~60–90°). Naupliar eye subtriangular. Antenna I long with 10–15 lobes (HT: 11, mean: 13), reaching to antenna II flagellomeres VI–VIII (HT: VIII, mean: VII). Antenna II with 10–14 flagellomeres (HT: 12, mean: 12).

THORAX. 21–22 (HT: 22, mean: 22) segments, 20–22 (HT: 21, mean: 21) thoracopod-bearing and none to one posterior limbless segment not reaching dorsal margin. Last ~13 thoracopod-bearing segments with spine and/or setae bearing dorsal extensions. Dorsal extensions increasing in size posteriorly over successive segments; segments with several short spines, in posterior segments central spine stouter.

THORACOPOD III (only P.91717; Fig. 44l). 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 subequal in extension to endopod, dorsal extension wide, narrowing distally, overreaching epipod. Epipod long, cylindric.

TELSON ( Fig. 44m –n). 15–34 spines (HT: 34; mean: 24). First (anterior) spine greatly enlarged. Following spines subequal in length, thin, elongate, aciculate (anterior ¼ of spines slightly broader and slightly conical), posterior spines increasing in size, very densely spaced; 1 (rarely 2) slightly larger spines interspersed (about mid-length of telson). Dorsal margin strongly concavely curved; in some individuals anteriorly convex and posteriorly concavely curved (reverse s-shaped). Right terminal claw more strongly curved than left.

FURCA ( Fig. 44m –n). Proximally with dorsomedial longitudinal row of 2–8 (HT: 7, mean: 6) setae, row ending distally in a single conical spine. Distal part ½–⅔ of furcal length, with numerous small denticles.

Females

Overall appearance as in males. Carapace ( Fig. 44b) length 3.7–7.0 mm (mean: 4.9 mm), height 2.2– 4.4 mm (mean: 3.0 mm); 19–33 growth lines, 16–25 widely spaced and 2–17 crowded; Cr/L 0.24– 0.27 and b/H 0.50–0.58. Nauplius eye subtriangular to suboval. Rostrum protruding dorsally in some individuals, anterior margin slightly concave and undulating; apex pointed, nearly rectangular angle, tip drawn out; ventral margin slightly concave, lacking anterior notch; overall rostrum shape trapezoidal ( Fig. 44k). Antenna I with 8–13 small lobes, lobes smaller than in males, often poorly separated from each other; reaching to antenna II flagellomeres III–VI. Antenna II with 9–12 flagellomeres. Telson with 18–37 dorsal spines; left and right terminal claws equally curved. Furca with 2–5 setae, distal part ½–¾ of furcal length.

Distribution ( Fig. 44o)

Ozestheria selmae sp. nov. is widely distributed in eastern and central Australia. It occurs in northern New South Wales, southern Queensland as well as Southern Northern Territory and northern and central South Australia. It occurs mostly in clear, freshwater habitats, but has also been collected in turbid claypans and hyposaline habitats.

Remarks

Ozestheria selmae sp. nov. is part of a group of five very closely related species; see remarks on O. typica comb. nov. for details. Ozestheria selmae ( Fig. 6) occupies a large and central area in the morphospace of the long-condyled species of Ozestheria . Ozestheria selmae is generally distinct from O. frederikeae sp. nov., O. sivesae sp. nov., O. mariae , O. gemina sp. nov., O. ngamurru sp. nov. and O. carnegiensis sp. nov., and overlaps with all other long-condyled species.