Ozestheria pilbarensis, 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 : 111-114

Ozestheria pilbarensis sp. nov.

urn:lsid:zoobank.org:act:60D47D2F-631C-4827-B60E-790AD149B197

Fig. 35

Diagnosis

Ozestheria pilbarensis sp. nov. is characterized by a long condyle and a very narrow occipital notch; carapace ornamentation dorsally on carapace polygonal (may appear granular), following growth bands with intensely anastomosing and branching lirae giving the impression of large pits or reticulations between lirae), lirae more pronounced posteriorly and ventrally on carapace; male rostrum with straight to slightly convex anterior margin, apex weakly rounded (not pointed) with acute angle (~70°), ventral margin concave with slight notch anteriorly; female rostrum with straight (becoming weakly concave ventrally) anterior margin, apex pointed (~70°) and not drawn out into acute tip, ventral margin nearly straight; 15–18 (male) or 13–19 (female) antenna I lobes reaching to antenna II flagellomeres X–XI (male) or V–X (female); 14–15 (male) or 13–15 (female) antenna II flagellomeres; 23–24 complete thorax segments; 21–33 mostly small telsonic spines, 1–2 larger spines interspersed, anterior spines conical, posterior spines elongated and aciculate, but not increasing in size; 10–15 furcal setae.

Differential diagnosis

Ozestheria pilbarensis 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. marthae sp. nov., O. selmae sp. nov., O. radiata sp. nov., O. bourkensis sp. nov., O. jonnae 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. and O. weeksi sp. nov., and differentiating these species can be difficult. However, O. pilbarensis differs from all these species by having more complete thorax segments (23–24) and from most of these species (except O. fuersichi ) by having polygonal reticulations in the first (larval) growth bands.

Etymology

The species is named after the Pilbara region in Western Australia where the species lives.

Type material

Holotype

AUSTRALIA – Western Australia • ♂; Pilbara, Red Rock on Indee Station ; 20°52′32.8″ S, 118°35′16.6″ E; 31 Jan. 2006; J. McRae leg.; WAM C78014 .

Paratypes

AUSTRALIA – Western Australia • 1 ♂, 2 ♀♀; same data as for holotype; WAM C80234 to C80236 • 1 ♂; same data as for holotype; NHMW-ZOO-CR-29003 .

Other material examined

AUSTRALIA – Western Australia • 1 ♂, 2 ♀♀; 14 Mile Pool , 114 km N of Newman; 22°33′13″ S, 119°51′49.1″ E; 15 Mar. 2016; A.M. Pinder leg.; WAM C77995 , C80230 , C80231 .

Type locality

Western Australia, Pilbara, Red Rock on Indee Station, 20°52′32.8″ S, 118°35′16.6″ E.

Description

Males

CARAPACE ( Fig. 35a, c–d). Length 6.5–6.8 mm (HT: 6.6 mm), height 3.9–4.1 mm (HT: 4.1 mm). Coloration varying from light brownish to yellow-orange and reddish-brown; outer margin lighter. 28–35 (HT: 28) growth lines, 16–24 (HT: 17) widely spaced and 9–19 (HT: ~11) crowded.

CARAPACE SHAPE. Dorsal margin straight, distinct dorso-posterior corner. Posterior margin broadly rounded, suboval, supra- to equicurvate (b/H 0.44–0.52; HT: 0.45). Ventral margin broadly rounded. Umbo position anterior (Cr/L 0.23–0.25; HT: 0.23).

CARAPACE ORNAMENTATION ( Fig. 35e–g). Larval valve and first few growth bands with shallow, inconspicuous, small reticulations (poorly visible in many specimens, may appear granular or punctate) forming mainly irregular pentagons or hexagons. Reticulations replaced by lirae in first few growth bands. Lirae subparallel, strongly anastomosing, reticulating and branching; lirae more pronounced posteriorly on carapace. Under SEM, fine punctae visible between lirae of non-crowded growth bands in mid-carapace. Crowded growth bands with pronounced, parallel lirae (visible predominately under SEM). Concentric ridges raised; under SEM smooth in early ontogenetic stages and with nodules at the upper margin in moniliform row in later ontogenetic stages. Spiniform as well as filiform setae present (mainly preserved ventrally on concentric ridges); setal pores in single row along all growth lines.

HEAD ( Fig. 35h). Condyle long, distally rounded; occipital notch narrow. Condyle lacking anterobasal hump. Margin between condyle and ocular tubercle straight. Ocular tubercle weakly developed, forming obtuse, nearly right angle with rostrum. Anterior margin of rostrum straight to weakly convex. Apex weakly rounded (not pointed), acute (~70°). Ventral margin of rostrum concave with slight notch anteriorly. Naupliar eye elongate, suboval. Antenna I long with 15–18 lobes (HT: 18), reaching to antenna II flagellomeres X–XI (HT: XI). Antenna II with 14–15 flagellomeres (HT: 15).

THORAX. 24–25 (HT: 25) segments, 23–24 (HT: 24) thoracopod-bearing and one posterior limbless segment not reaching dorsal margin. Most thoracopod-bearing segments with spine bearing dorsal extensions.

THORACOPOD III (only WAM C78014; Fig. 35k). Endite I short and curved dorsally. Endites II–V broad, decreasing in size. Endite V palp one-segmented. Exopod ventral extension subequal in extension to endopod, dorsal extension wide, narrowing distally, overreaching epipod. Epipod long, cylindric.

TELSON ( Fig. 35j). 23–28 spines (HT: 26). First (anterior) spine enlarged. Following spines mostly small, anteriorly slender, conical, unequal in size (one or two notably larger spines interspersed); posterior ⅔ or ¼ of spines more elongate, slender, aciculate, not increasing in length posteriorly. Spines equally spaced. Dorsal margin nearly straight. Right terminal claw more strongly curved.

FURCA ( Fig. 35j). Proximally with dorsomedial longitudinal row of 10–15 (HT: 15) 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. 35b) length 6.4–7.3 mm, height 3.9–4.4 mm; 29–34 growth lines, of these 17–29 widely spaced and 5–13 crowded; Cr/L 0.21–0.23, b/H 0.46–0.49. Angle between head and rostrum obtuse (~110°) ( Fig. 35i). Rostrum frontal margin straight, becoming weakly concave ventrally. Apex pointed (~70°), not drawn out into acute tip; ventral margin nearly straight. Antenna I with 13–19 small lobes, lobes smaller than in males; reaching to antenna II flagellomeres V–X.Antenna II with 13–15 flagellomeres. 25 thorax segments, 24 thoracopod-bearing and one posterior limbless segment not reaching dorsal margin. Telson with 21–33 dorsal spines; left and right terminal claws usually equally curved, sometimes right stronger curved. Furca with 8 setae.

Distribution ( Fig. 35l)

Ozestheria pilbarensis sp. nov. is known only from two localities in the Pilbara region in northwestern Western Australia.

Remarks

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