Ozestheria fuersichi, 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 : 56-60

Ozestheria fuersichi sp. nov.

urn:lsid:zoobank.org:act:862B6BE4-936F-4F8A-A2F0-B8BB4581CE5B

Fig. 19

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

Diagnosis

Ozestheria fuersichi sp. nov. is characterized by a long condyle and a narrow occipital notch; carapace ornamentation on larval valve and first growth bands tiny polygonal reticulation, following growth bands with widely spaced subparallel lirae, punctae (hardly visible) between lirae; male rostrum with weakly convex to straight anterior margin, apex pointed with acute angle (~60°) rarely rounded, ventral margin concavely curved; female rostrum with concave anterior margin, apex weakly drawn out and pointed with acute angle (~70–80°), ventral margin weakly convex to straight; 13–14 (male) or 10–16 (female) antenna I lobes reaching to antenna II flagellomeres VI–VIII (male) or IV–V (female); 10–12 (male) or 11–14 (female) antenna II flagellomeres; 22 complete thorax segments; 19–25 telsonic spines, spines short with 1–4 larger spines interspersed, anterior spines conical, posterior spines increase slightly in size and are longer, drawn out, aciculate and more closely spaced; 6–10 furcal setae.

Differential diagnosis

Ozestheria fuersichi 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 the carapace, transitioning to distinct, subparallel lirae during ontogeny), except from O. cancellata comb. nov., O. minor comb. nov., O. typica comb. nov., O. jonnae sp. nov., O. marthae sp. nov., O. selmae 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 fuersichi differs from these species in having polygonal ornamentations on the ontogenetically earliest growth bands (shared only with O. pilbarensis ), widely spaced lirae that are not continuous but a row of nodular structures (only seen under SEM), in the shape of the male rostrum (which is more elongated and slender than in the other species), the shape of the female rostrum (with a concave anterior margin which curves the apex anteriorly) and the spination of the telson with several distinctly larger spines interspersed (though this is also present in some of the other species).

Etymology

The species is named after German paleontologist Franz T. Fürsich, honoring his significant contributions to invertebrate paleontology, which sparked MH’s curiosity in fossil clam shrimp.

Type material

Holotype

AUSTRALIA – Queensland • ♂; Barcaldine Region, pool next to Lake Dunn ; 22°36′16.4″ S, 145°40′21.8″ E; 14 Feb. 2010; M. Schwentner, C. Sieves and and B.V. Timms leg.; GenBank no: KJ705655 ( COI); AM P.91426.

Paratypes

AUSTRALIA – Queensland • 1 ♂, 1 ♀; same data as for holotype; GenBank nos: KJ705653, KJ705656 ( COI); AM P.91424, P.91427 • 1 ♀; same data as for holotype; GenBank no: KJ705654 ( COI); NHMW- ZOO-CR-28478 .

Other material examined

AUSTRALIA – Queensland • 1 ♂; old dugout close to Lake Dunn ; 22°36′12.9″ S, 145°40′26.6″ E; 14 Feb. 2010; M. Schwentner, C. Sieves and B.V. Timms leg.; AM P.91420 • 3 ♀♀; old borrow pit, Monklands Road ; 23°37′34.8″ S, 146°21′11.7″ E; 14 Feb. 2010; M. Schwentner, C. Sieves and B.V. Timms leg.; AM P.91421 to P.91423 .

Type locality

Australia, Queensland, Barcaldine Region, pool next to Lake Dunn, 22°36′16.4″ S, 145°40′21.8″ E.

Description

Males

CARAPACE ( Fig. 19a–c). Length 3.7–4.3 mm (HT: 3.7 mm), height 2.3–2.7 mm (HT: 2.3 mm). Coloration light brown, outer margin lighter. 19–21 growth lines (HT: 19), 15–18 (HT: 16) widely spaced and 3–6 (HT: 3) crowded.

CARAPACE SHAPE. Dorsal margin straight, distinct dorso-posterior corner. Posterior margin broadly rounded, weakly extending posteriorly, supracurvate to equicurvate (b/H 0.46–0.49, HT: 0.46). Ventral margin nearly straight. Umbo position submedian (Cr/L 0.26–0.27, HT: 0.26).

CARAPACE ORNAMENTATION ( Fig. 19d–e). Larval valve and following few growth bands covered in mesh of shallow, poorly visible polygonal reticulations, mostly tetragons, pentagons and hexagons. Following growth bands with widely spaced, subparallel lirae; lirae dorsally often anastomosing or confluent, with shorter lirae intercalating on the ventral part of each growth band (predominantly in the posterior region of the carapace), under SEM lirae not continuous but formed by a series of nodular structures; punctae interspersed between lirae (but poorly visible under incident light). Crowded growth bands lacking apparent ornamentation (punctate under SEM). Concentric ridges raised. Setae filiform, under SEM a single row of setal pores along all growth lines.

HEAD ( Fig. 19g). Condyle long, distally rounded; occipital notch narrow. Condyle with weakly developed or absent anterobasal hump. Margin between condyle and ocular tubercle straight to weakly concave. Ocular tubercle weakly developed, forming obtuse angle with rostrum (~120°). Anterior margin of rostrum weakly convex to straight (HT: weakly convex). Ventral margin of rostrum concavely curved with obtuse angle about half-length, pointing apex slightly downwards; apex pointed, acute (~60°), rarely rounded. Naupliar eye large and elongated, subrectangular with irregular margins to subtriangular or suboval. Antenna I with 13–14 lobes (HT: 14), reaching to antenna II flagellomeres VI–VIII (HT: VIII). Antenna II with 10–12 flagellomeres (HT: 11).

THORAX. 22–23 (HT: 22) segments, 22 thoracopod-bearing and none to one (HT: none) posterior limbless segment not reaching dorsal margin. Dorsal armature with thin and elongated spines, becoming shorter and stouter in posterior segments.

THORACOPOD III (only P.91426; Fig. 19f). Endite I short and curved dorsally. Endites II–V broad, decreasing in size. Endite V palp two-segmented, basal segment sub-equal to endopod. Exopod ventral extension shorter in extension to endopod, dorsal extension wide, narrowing distally, overreaching epipod. Epipod long, cylindric.

TELSON ( Fig. 19i). 19–23 spines (HT: 20). First (anterior) spine enlarged. Spines short, conical, subequal in size and spacing, slightly increasing in size posteriorly, with 1–4 (HT: 4) larger spines interspersed; posterior most spines slightly larger, drawn out and aciculate. Dorsal margin nearly straight. Terminal claws subequally curved.

FURCA ( Fig. 19i). Proximally with dorsomedial longitudinal row of 8–10 (HT: eight) setae, row ending distally in a single conical spine. Distal part of ~⅔ of furca length, widely curved, with numerous small denticles.

Females

Very similar to males. Carapace length 4.4– 5.1 mm, height 2.7 – 3.2 mm. 17–19 growth lines, of these 15–18 widely spaced and 0–3 crowded; Cr/L 0.24–0.28 and b/H 0.44–0.49. Ocular tubercle and rostrum form nearly straight angle ( Fig. 19h). Anterior margin of rostrum concave, apex weakly drawn out, pointed, with acute angle (~70–80°), ventral margin weakly convex to straight. Antenna I with 10–16 indistinct lobes, reaching to antenna II flagellomeres IV–V. Antenna II with 11–14 flagellomeres. Telson 19–25 spines ( Fig. 19j), shape and arrangement as in males. Furca bearing 6–10 setae.

Distribution ( Fig. 19k)

The species occurs in central Queensland, in the northern regions of the Cooper Creek catchment.

Remarks

The carapace shape of Ozestheria fuersichi sp. nov. ( Fig. 6) is distinct from all that of other species in the analysis of short-condyled species ( Fig. 5). In the analysis of long-condyled species, O. fuersichi overlaps partly with O. minor comb. nov., O. selmae sp. nov., O. cancellata comb. nov. and O. weeksi sp. nov. and fully with O. setifera sp. nov.