Ozestheria jiangi, 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 : 71-75

Ozestheria jiangi sp. nov.

urn:lsid:zoobank.org:act:A52D9D02-6C4F-42E4-A638-7BEABE7D3A3E

Fig. 23

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

Diagnosis

Ozestheria jiangi sp. nov. is characterized by a long condyle and a narrow occipital notch; nearly straight ventral carapace margin; carapace ornamentation dorsally on carapace and dorsally within subsequent growth bands lacking (smooth, no punctae), short, well-developed radial lirae appearing ventrally within growth bands from about mid-dorsal carapace, lirae increasing in length in following growth bands; carapace setae long and thin (usually only few preserved ventrally and posteriorly on carapace); many individuals with small tubercle ventrally below eye; male rostrum with straight (sometimes undulating) anterior margin, apex rounded with acute angle (~45°), ventral margin strongly concave, pointing apex downwards; female rostrum anterior margin straight or undulating, apex drawn out into acute tip, ventral margin weakly concave; 14–19 (male) or 10–15 (female) antenna I lobes reaching to antenna II flagellomeres VII–X (male) or IV (female); 12–15 (male) or 12–14 (female) antenna II flagellomeres; 19–23 complete thorax segments; 15–28 telsonic spines, anteriorly short and thin, posteriorly (from about mid) aciculate and strongly increasing in size; 2–12 furcal setae.

Differential diagnosis

Ozestheria jiangi sp. nov. can be easily differentiated from most other Australian species of Ozestheria by its characteristic carapace ornamentation: within growth bands surface dorsally smooth and ventrally with well-defined, subparallel lirae, which increase in size within progressing growth bands (whereas the smooth area decreases in size). Other species with (partly) smooth growth bands are O. echidna sp. nov., O. setifera sp. nov. and O. sivesae sp. nov. These differ in the shape of the male and female rostrum and the spination of the telson (posterior spines longer in O. jiangi ). Furthermore, Ozestheria echidna and Ozestheria setifera are characterized by a large number of densely arranged setae on the carapace (these are mostly broken off in O. jiangi ), also O. echidna features only short lirae mid-dorsally and posteriorly on the carapace (ventrally on carapace growth bands predominantly smooth). While lirae in later growth bands become longer in Ozestheria jiangi they become shorter in O. echidna . Ozestheria sivesae and O. setifera have less regular (nodulous and/or intermittent) lirae. Ozestheria sivesae and O. echidna yield additional punctate ornamentation.

Etymology

The species is named after the Chinese paleontologist Baoyu Jiang, honoring his contributions to Chinese paleontology and his work on clam shrimp-rich Mesozoic lake deposits.

Type material

Holotype

AUSTRALIA – Queensland • ♂; Currawinya National Park, claypan halfway along northern fence of Bilby enclosure; 28°52′12.8″ S, 144°21′52.1″ E; 25 Feb. 2011; M. Schwentner, S. Richter and B.V. Timms leg.; GenBank no: KJ705681 ( COI); AM P.91452.

Paratypes

AUSTRALIA – Queensland • 2 ♂♂, 1 ♀; same data as for holotype; GenBank nos: KJ705680, KJ705682, KJ705683 ( COI); AM P.91451, P.91453, P.91454 • 1 ♂; same data as for holotype; GenBank no: KJ705684 ( COI); NHMW-ZOO-CR-28477 .

Other material examined

AUSTRALIA – New South Wales • 1 ♀; Bloodwood Station , cane grass swamp SE of woolshed; 29°31′35.3″ S, 144°51′39.2″ E; 21 Feb. 2011; coll. M. Schwentner, S. Richter and B.V. Timms leg.; AM P. 91462 • 1 ♂; claypan-like 19 km E of Engonia ; 29°17′06.9″ S, 146°02′23.9″ E; 21 Jan. 2010; M. Schwentner and B.V. Timms leg.; AM P.91464 • 1 ♀; E of Lake Lauradale ; 29°51′22″ S, 145°38′49″ E; 29 Mar. 2009; M. Schwentner and B.V. Timms leg.; AM P.91437 • 1 ♂; E of Lake Lauradale ; 29°51′22″ S, 145°38′49″ E; 18 Jan. 2010; M. Schwentner and B.V. Timms leg.; AM P.91463 . – Northern Territory • 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. 91439, P.91440 . – Queensland • 5 ♂♂; Currawinya National Park, Big Darko Claypan ; 28°52′19.1″ S, 144°17′34.5″ E; 25 Feb. 2011; M. Schwentner, S. Richter and B.V. Timms leg.; AM P.91456 to P.91460 • 1 ♀; Currawinya National Park , bokeen cane grass swamp; 28°49′55.3″ S, 144°20′59.3″ E; 24 Feb. 2011; M. Schwentner, S. Richter and B.V. Timms leg.; AM P.91471 • 5 ♂♂; claypan 46 km E of Thargomindah ; 28°05′16.0″ S, 144°16′01.7″ E; 27 Feb. 2011; M. Schwentner and B.V. Timms leg.; AM P.91446 to P.91450 • 1 ♂, 4 ♀♀; claypan 46.5 km W of Windorah ; 25°20′20.1″ S, 142°12′20.9″ E; 2 Mar. 2011; M. Schwentner and B.V. Timms leg.; AM P. 91441 to P.91445 .

Additional material (not examined)

AUSTRALIA – New South Wales • 1 juv.; Muella Station, Lower Lake Eliza ; 29°25′28.9″ S, 145°03′41.8″ E; 22 Feb. 2011; M. Schwentner, S. Richter and B.V. Timms leg.; AM P.91461 • 2 juvs; claypan-like 19 km E of Engonia ; 29°17′06.9″ S, 146°02′23.9″ E; 21 Jan. 2010; M. Schwentner and B.V. Timms leg.; AM. P.91472, P.91473 . – Queensland • 5 juvs; Oakham claypan; 25°23′16.4″ S, 143°10′45.4″ E; 8 Apr. 2009; M. Schwentner and B.V. Timms leg.; AM P.91465 to P.91467, P.91438 .

Type locality

Australia, Queensland, Currawinya National Park, claypan halfway along northern fence of Bilby enclosure, 28°52′12.8″ S, 144°21′52.1″ E.

Description

Males

CARAPACE ( Fig. 23a, c–d). Length 4.3–7.3 mm (HT: 6.9 mm, mean: 6.3 mm), height 2.5–4.3 (HT: 4.1 mm, mean: 3.8 mm). Coloration orange to red-orange, crowded growth bands lighter, often whitish; colour returns in growth bands of the secondary growth phase. 18–42 (HT: 37, mean: 31) growth lines, 17–30 (HT: 18, mean: 23) widely spaced, in some individuals 3–4 additional widely spaced (secondary growth phase; HT: 4) among crowded, and 1–15 (HT: 15, mean: 8) crowded.

CARAPACE SHAPE. Dorsal margin straight, distinct dorso-posterior corner. Posterior margin broadly rounded, suboval, equicurvate to infracurvate (b/H 0.51–0.59, HT: 0.56, mean: 0.55). Ventral margin nearly straight. Umbo position anterior to submedian (Cr/L 0.23–0.27, HT: 0.23, mean: 0.25).

CARAPACE ORNAMENTATION ( Fig. 23e–f). Larval valve smooth. In the dorsal and median part of the carapace, growth bands smooth. Radial lirae appearing, thickening and lengthening on the ventral part of successive growth bands; on ventral and crowded growth bands no smooth parts visible. Lirae subparallel and ± equidistant on successive growth bands, also on growth bands of the secondary growth phase. Concentric ridges slightly raised, with moniliform nodules on the dorsal margin and a serrated ventral margin (the latter two not visible in all individuals, best seen under SEM). Setae filiform, preferentially preserved on the midposterior and posteroventral part of carapace (setal pores in single row along all growth lines under SEM).

HEAD ( Fig. 23h). Condyle long, distally acute; occipital notch narrow. Condyle lacking anterobasal hump. Margin between condyle and ocular tubercle straight to slightly convex. Ocular tubercle weakly developed, forming obtuse, nearly straight angle with rostrum. Small tubercle ventrally below eye in most specimens (HT: present). Anterior margin of rostrum straight to weakly convex, sometimes undulating (HT: straight). Apex weakly rounded, acute (~45°). Ventral margin of rostrum deeply concave with obtuse angle about half-length, pointing apex slightly downwards. Naupliar eye triangular. Antenna I long with 15–19 lobes (HT: 17; mean: 16), reaching to antenna II flagellomeres VI–X (HT: IX; mean: VIII). Antenna II with 12–15 flagellomeres (HT: 13; mean: 13).

THORAX. 21–23 (HT: 22; mean: 22) segments, 21–22 (HT: 21; mean: 22) 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). Spines short and stout, in posterior segments central spines stouter but shorter.

THORACOPOD III (only P.91452; Fig. 23j). 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, overreaching epipod. Epipod long, cylindric.

TELSON ( Fig. 23k–l). 15–26 spines (HT: 24; mean: 22). First (anterior) spine enlarged. Spines on anterior half of telson short, thin, aciculate, subequal in length; one or a few anterior spines not on dorsal margin but slightly lateral. Spines on posterior half increasing in size, thin, aciculate and very closely spaced. Dorsal margin concavely curved, sometimes undulating (anteriorly convex, posteriorly concave). Right terminal claw more strongly curved than left.

FURCA ( Fig. 23k–l). Proximally with dorsomedial longitudinal row of 5–11 (HT: 7) setae, row ending distally in a single conical spine. Distal part ⅓–⅔ of furcal length, with numerous small denticles.

Females

Overall appearance as in males. Carapace ( Fig. 23b) length 5.4–6.3 mm (mean: 5.8 mm), height 3.3– 4.1 mm (mean: 3.6 mm); 22–38 (mean: 30) growth lines, of these 18–26 (mean: 22) widely spaced, in some individuals 4–5 additional widely spaced (secondary growth phase) among crowded, and 1–12 (mean: 10) crowded; Cr/L 0.21–0.28 and b/H 0.51–0.60. Apex of rostrum drawn out into acute tip, ventral margin only weakly concave, overall rostrum shape trapezoidal ( Fig. 23i). Antenna I with 10–15 small lobes (mean: 13), lobes smaller than in males; reaching to antenna II flagellomeres III–IV (mean: IV). Antenna II with 12–14 flagellomeres (mean: 12). 20–23 (mean: 22) segments, of these 19–23 (mean: 22) thoracopod-bearing and none to one posterior limbless segment not reaching dorsal margin. Telson with 17–28 (mean: 22) dorsal spines; left and right terminal claws equally curved ( Fig. 23m). Furca with 2–7 setae (mean: 5).

Distribution ( Fig. 23n)

Common and widely distributed in the arid regions of northern New South Wales and southern and central Queensland (e.g., catchments of northern Murray-Darling Basin, Bulloo River or central Cooper Creek catchment) with few records in central Australia. This species lives exclusively in claypans or cane grass swamps, which usually are very turbid.

Remarks

The carapace shape of Ozestheria jiangi sp. nov. ( Fig. 6) is distinct from that of most other species and overlaps partly with those of O. minor comb. nov., O. selmae sp. nov., O. typica comb. nov., O. jonnae sp. nov., O. bourkensis sp. nov., O. cancellata comb. nov., O. rincewindi sp. nov., O. weeksi sp. nov., O. glabra sp. nov., and O. echidna sp. nov.