Ozestheria setifera, 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 : 143-147

Ozestheria setifera sp. nov.

urn:lsid:zoobank.org:act:D9452DA6-013B-46C2-9FCF-96D868320BF0

Fig. 45

Ozestheria sp. K – Schwentner et al. 2015a: figs 2, 6; 2020: figs 1–2. — Hethke et al. 2023: fig. 10.

Diagnosis

Ozestheria setifera sp. nov. is characterized by a long condyle and a narrow occipital notch; a widely rounded ventral carapace margin; carapace ornamentation within all non-crowded growth bands dorsally smooth and ventrally with irregular short lirae, smooth area can be very narrow and usually decreases in size ventrally on carapace; carapace setae mid-long and thick, usually very dense on most growth lines; male rostrum with strongly convex anterior margin, apex rounded with rectangular angle, ventral margin straight (except anterior notch); female rostrum anterior margin weakly convex, apex rectangular and weakly rounded, ventral margin straight or weakly convex; 10–16 (male) or 10–16 (female) antenna I lobes reaching to antenna II flagellomeres IV–VIII (male) or II–V (female); 10–14 (male) or 9–14 (female) antenna II flagellomeres; 18–21 complete thorax segments; 18–31 telsonic spines, anterior two-thirds conical with two or three larger spines interspersed, posterior spines aciculate and slightly increasing in size; 2–8 furcal setae.

Differential diagnosis

Ozestheria setifera sp. nov. can be easily differentiated from most other Australian species of Ozestheria by the dense setation of the carapace (in most other species the majority of setae are broken off) and the characteristic carapace ornamentation with the smooth band dorsally within growth bands. Ozestheria echidna sp. nov. also has such dense carapace setation, but here setae are even longer and carapace ornamentation features only very short, faint lirae and only mid-dorsally on the carapace (ventrally on carapace growth bands completely smooth), the hump at the base of the condyle is usually absent and the telson has a larger number of setae (28–44 vs 18–31). Ozestheria jiangi sp. nov. and O. echidna also have smooth bands in their carapace ornamentation, but lack the dense setation and differ in the shape of the male and female rostrum. In O. jiangi the smooth section within growth bands is more extensive dorsally on the carapace, where the whole growth band can be smooth (in O. setifera lirae are always present ventrally within growth bands).

Etymology

The species name derives from the Latin words ‘ seta ’ (‘bristle’) and ‘ ferre ’ (‘to bear’), referring to the dense and stout setation on the carapace.

Type material

Holotype

AUSTRALIA – New South Wales • ♂; Bloodwood Station, Marsilea Pan , 29°32′13.2″ S, 144.52′26.3″ E; 19 Feb. 2010; M. Schwentner, C. Sieves and B.V. Timms leg.; GenBank no: KJ705808 ( COI); AM P.91580.

Paratypes

AUSTRALIA – New South Wales • 13 ♂♂, 13 ♀♀; same data as for holotype; GenBank nos: KJ705791 to KJ705794, KJ705809 to KJ705824, KJ705826 to KJ705831 ( COI); AM P.91563 to P.91566, P.91581 to P.91596, P.91598 to P.91603 • 1 ♂; same data as for holotype; GenBank no: KJ705824 ( COI); NHMW-ZOO-CR-28483 • 6 ♂♂, 3 ♀♀; same data as for holotype; 30 Mar. 2009; M. Schwentner and B.V. Timms leg.; GenBank nos: KJ705783 to KJ705787, KJ705832 to KJ705834, KJ705836 ( COI); AM P.91555 to P.91559, P.91604 to P.91606, P.91608 .

Other material examined

AUSTRALIA – New South Wales • 5 ♂♂; Muella Station, Muella Vegetated Pool 1; 29°31′10.3″ S, 144°56′21.8″ E; 31 Mar. 2009; M. Schwentner and B.V. Timms leg.; AM P.91550 to P.91554 • 1 ♂, 1 ♀; Muella Station, Muella Vegetated Pool 2; 29°31′00.3″ S, 144°56′22.7″ E; 31 Mar. 2009; M. Schwentner and B.V. Timms leg.; AM P.91560, P.91561 • 1 ♂, 1 ♀; Muella Station, Muella Vegetated Pool 2; 29°31′00.3″ S, 144°56′22.7″ E; 19 Jan. 2010; M. Schwentner and B.V. Timms leg.; AM P.82539, P.82540 • 1 ♀; Muella Station, Muella Vegetated Pool 3; 29°30′12.0″ S, 144°55′37.4″ E; 31 Mar. 2009; M. Schwentner and B.V. Timms leg.; AM P.91562 • 1 ♂, 1 ♀; claypan-like W of Engonia ; 29°18′32.8″ S, 145°44′06.9″ E; 21 Jan. 2010; M. Schwentner and B.V. Timms leg.; AM P.91610, P.91611 . – Queensland • 3 ♂♂, 1 ♀; coolibah swamp W of road; 28°50′51.9″ S, 143°53′54.4″ E; 26 Feb. 2011; M. Schwentner, S. Richter and B.V. Timms leg.; AM P.91574 to P.91577 • 1 ♂; beefwood grassy swamp; 28°50′34.5″ S, 143°53′47.3″ E; 26 Feb. 2011; M. Schwentner, S. Richter and B.V. Timms leg.; AM P.91609 • 1 ♂, 4 ♀♀; swamp near Thargomindah Station ; 28°03′12.5″ S, 143°47′11.5″ E; 26 Feb. 2011; M. Schwentner, S. Richter and B.V. Timms leg.; AM P.91569 to P.91573 • 2 ♀♀; horse paddock claypan on Springfield Station ; 25°49′29.6″ S, 143°04′07.9″ E; 1 Mar. 2011; M. Schwentner and B.V. Timms leg.; AM P.91567, P.91568 .

Additional material (not examined)

AUSTRALIA – New South Wales • 2 juvs; Bloodwood Station , dead ram pan; 29°31′45.4″ S, 144°52′05.4″ E; 21 Feb. 2011; M. Schwentner, S. Richter and B.V. Timms leg.; AM P.91578, P.91579 .

Type locality

New South Wales, Bloodwood Station, Marsilea Pan, 29°32′13.2″ S, 144.52′26.3″ E.

Description

Males

CARAPACE ( Fig. 45a, c–d). Length 3.6–5.2 mm (HT: 4.9 mm, mean: 4.4 mm), height 2.1–3.1 (HT: 2.9 mm, mean: 2.6 mm). Coloration yellow-orange, becoming lighter towards outer margin. 15–28 (HT: 20,

mean: 20) growth lines, 11–20 (HT: 17, mean: 16) widely spaced and 0–12 (HT: 3, mean: 4) crowded.

CARAPACE SHAPE. Dorsal margin straight, rounded dorso-posterior corner. Posterior margin broadly rounded, supracurvate to equicurvate (0.38–0.48, HT: 0.46, mean: 0.44). Ventral margin widely curved, central section nearly straight. Umbo position anterior to submedian (Cr/L 0.21–0.28, HT: 0.24, mean: 0.25).

CARAPACE ORNAMENTATION ( Fig. 45e–h). Larval valve smooth or granulate, under SEM finely reticulated, transitioning to punctate on the following growth bands. In the dorsal and median part of the carapace, dorsalmost part of each growth band smooth, transitioning into ornamentation with short, intermittent, curved, anastomosing lirae (nodular under SEM); most individual lirae do not reach across ornamented region. In some individuals smooth section very narrow. In ventral growth bands the smooth area is reduced and nodular lirae dominate. Lirae stronger and slightly more regular in the posterior region of the carapace. Crowded growth bands with inconspicuous nodular ornamentation. Concentric ridges raised. Setae very dense, thick and mid-long, usually preserved along most growth lines. Setal pores in 2–3 rows on concentric ridges along all growth lines.

HEAD ( Fig. 45i–k). Condyle long, distally acute; occipital notch narrow. Condyle with anterobasal hump. Margin between condyle and ocular tubercle strongly concave. Ocular tubercle weakly or well developed, forming obtuse angle with rostrum (varying between ~110°–170°). Anterior margin of rostrum strongly convex. Apex rounded, ~90°. Ventral margin of rostrum with anterior notch in most specimens, otherwise straight. Naupliar eye elongate, sub-rectangular to sub-triangular. Antenna I long with 10–16 lobes (HT: 12; mean: 13), reaching to antenna II flagellomeres IV–VIII (HT: VII; mean: VII). Antenna II with 10–14 flagellomeres (HT: 12; mean: 12).

THORAX. 19–21 (HT: 21; mean: 20) segments, 19–21 (HT: 20; mean: 19) thoracopod-bearing and none to one (HT: one) posterior limbless segment not reaching dorsal margin. Last ~14 thoracopod-bearing segments with spine bearing dorsal extensions. Dorsal extensions increasing in size posteriorly over successive segments (until ~7 th last segment). First segments with long setae, central setae turning into stout spines in posterior segments.

THORACOPOD III (only P.91580; Fig. 45m). Endite I short and curved dorsally. Endites II–V broad, decreasing in size. Endite V palp two-segmented, basal segment longer than endopod. Exopod ventral extension subequal in extension to endopod, dorsal extension wide, narrowing distally, overreaching epipod. Epipod long, cylindric.

TELSON ( Fig. 45n–o). 18–26 spines (HT: 23, mean 22). First (anterior) spine enlarged. Spines on anterior two-thirds of telson of varying size, mostly conical. Two or three slightly larger and stouter spines interspersed. Spines on posterior third of telson thinner, subequal in size. Dorsal margin nearly straight, slightly convex in center. Right terminal claw more strongly curved than left.

FURCA ( Fig. 45n–o). Proximally with dorsomedial longitudinal row of 2–8 (HT: 4, mean: 5) 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. 45b) length 3.6–5.4 mm (mean: 4.5 mm), height 2.2– 3.5 mm (mean: 2.8 mm); 16–28 (mean: 21) growth lines, 13–20 (mean: 17) widely spaced, and 1–9 (mean: 4) crowded; dorso-posterior corner rounded or distinct angle; Cr/L 0.21–0.27 (mean: 0.24) and b/H 0.38– 0.48 (mean: 0.44). Margin between condyle and ocular tubercle weakly to strongly concave ( Fig. 45l). Angle between ocular tubercle and rostrum obtuse, usually close to 180°, rarely ~110°. Anterior margin of rostrum weakly convex; apex rectangular, not or only weakly rounded, not drawn out; ventral margin straight, rarely weakly convex, lacking anterior notch; overall rostrum shape trapezoidal. Antenna I with 10–16 small lobes (mean: 12), lobes smaller than in males; reaching to antenna II flagellomeres II–V (mean: IV). Antenna II with 9–14 flagellomeres (mean: 11). 19–21 (mean: 20) segments, of these 18–20 (mean: 19) thoracopod-bearing and none to one posterior limb-less segment not reaching dorsal margin. Telson with 20–31 (mean: 25) dorsal spines; right terminal claws stronger curved (as in males). Furca with 2–7 setae (mean: 4); distal part ⅔–¾ of furcal length.

Distribution ( Fig. 45p)

The species is not very common. It occurs predominately in vegetated, grassy swamps in northern New South Wales and southern Queensland, in the catchments of the Paroo River and the central Cooper Creek.

Remarks

The carapace shape of Ozestheria setifera sp. nov. ( Fig. 6) is distinct from that of many other species and overlaps partly with those of O. minor comb. nov., O. timmsi sp. nov., O. sivesae sp. nov., O. gemina sp. nov., O. marthae sp. nov., O. selmae sp. nov., O. cancellata comb. nov., O. weeksi sp. nov., O. quinlanae sp. nov., O. pilbarensis sp. nov. and fully with O. fuersichi sp. nov. and O. barcaldinensis sp. nov.