Ozestheria glabra, 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 : 65-66

Ozestheria glabra sp. nov.

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Fig. 21

Diagnosis

Ozestheria glabra 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, less anastomosing and more pronounced with progressing growth bands, lirae terminate in nodule; male rostrum with straight anterior margin, apex broadly rounded with right angle, ventral margin weakly convex with pronounced anterior notch; 13 (male) antenna I lobes reaching to antenna II flagellomeres VIII (male); 16 (male) antenna II flagellomeres; 20 complete thorax segments; 11 telsonic spines, most spines small and conical with one larger spine interspersed, most spines crowded anteriorly on telson (spination pattern may be a growth defect); 11 furcal setae.

Differential diagnosis

Ozestheria glabra 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. barcaldinensis sp. nov., O. ngamurru sp. nov., O. beleriandensis sp. nov., O. quinlanae sp. nov., O. rincewindi sp. nov., O. pilbarensis sp. nov. and O. weeksi sp. nov., and differentiating these species can be difficult. Ozestheria glabra has fewer complete thorax segments than O. cancellata and O. jonnae , more antenna II flagellomeres, and the male rostrum has a more convex anterior margin and rounded apex than O. ngamurru .

Etymology

The species name derives from the Latin word ‘ glaber ’ (‘smooth’), referring to the conspicuous gap in telson spination.

Type material

Holotype

AUSTRALIA – Western Australia • ♂; Carnarvon Range Gully , 118 km E of Kumarina; 25°05′17.4″ S, 122°39′37.4″ E; 20 Mai 2013; K. Quinlan leg.; WAM C77996 .

Type locality

Western Australia, Carnarvon Range Gully, 118 km E of Kumarina, 25°05′17.4″ S, 122°39′37.4″ E.

Description

Male (holotype)

CARAPACE ( Fig. 21a–c). Length 7.1 mm, height 3.9 mm. Coloration brown. 59 growth lines, of these 17 widely spaced in the primary growth phase, 7 crowded growth lines, 10 widely spaced growth lines of secondary growth phase and 25 crowded growth lines.

CARAPACE SHAPE. Dorsal margin straight, dorso-posterior corner rounded. Posterior margin broadly rounded, suboval. Ventral margin broadly rounded. Umbo position submedian (Cr/L 0.28).

CARAPACE ORNAMENTATION ( Fig. 21d–h). Larval valve and dorsal growth bands punctate (best visible under SEM). In following growth bands, subparallel and weakly anastomosing lirae form ventrally within growth bands between punctae, lirae become more prominent and longer in subsequent growth bands. From about mid-carapace lirae distinct, subparallel (less anastomosing), spanning full growth bands and terminating in distinct nodule on concentric ridge. Crowded growth bands with short, distinct lirae. Growth bands of secondary growth phase with distinct, subparallel, slightly nodular lirae terminating in distinct nodule. Concentric ridges raised. No setae preserved (under SEM single row of setal pores along all growth lines).

HEAD ( Fig. 21i). Condyle long, distally rounded; occipital notch very narrow. Condyle with weakly developed anterobasal hump. Margin between condyle and ocular tubercle straight. Ocular tubercle weakly developed, forming obtuse angle (~120°) with rostrum. Frontal margin of rostrum straight, ventral margin weakly convex with pronounced anterior notch, apex rounded with right angle. Naupliar eye large, subtriangular, strongly rounded anteriorly. Antenna I with 13 lobes, reaching to antenna II flagellomere VIII. Antenna II anterior ramus 16 flagellomeres.

THORAX. 21 segments, 20 thoracopod-bearing and one limbless segment not reaching dorsal margin. From about midbody, thoracopod-bearing segments with dorsal extensions bearing spines.

THORACOPOD III (only WAM C77996; Fig. 21k). 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. 21j). 11 spines. First spine (anterior) enlarged. Most spines small, conical, and sub-equal in length and crowded at the anterior end of the telson; one larger spine interspersed and one aciculate spine posteriorly with wide gap between this and all other spines. Spination pattern appears to be a growth defect. Terminal claw strongly curved, more strongly curved on right body half. Dorsal margin nearly straight, posteriorly concavely curved.

FURCA ( Fig. 21j). Proximally with dorsomedial longitudinal row of 11 setae, row ending distally in a single conical spine. Distal part ~½ of furca length, with numerous small denticles.

Distribution ( Fig. 21l)

Currently known only from its type locality in central Western Australia.

Remarks

The carapace shape of the single specimen of Ozestheria glabra sp. nov. ( Fig. 6) is associated with that of O. jiangi sp. nov., O. minor comb. nov., O. jonnae sp. nov., O. selmae sp. nov., O. echidna sp. nov., and O. cancellata comb. nov.