Ozestheria weeksi, 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 : 159-162

Ozestheria weeksi sp. nov.

urn:lsid:zoobank.org:act:2787CF24-8E98-45FC-A8C2-E0ECFD67DBDE

Fig. 50

Ozestheria sp. Q2 – Schwentner et al. 2015a: figs 2, 6.

Diagnosis

Ozestheria weeksi 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 intensely anastomosing lirae forming ventrally within growth band, lirae become longer, less anastomosing and more pronounced with progressing growth bands; male rostrum with weakly convex anterior margin, apex rounded with nearly rectangular angle, ventral margin anteriorly convex, then straight or weakly concave; female rostrum with concave and dorsally strongly protruding (globose) anterior margin, apex rectangular and drawn out into acute tip, ventral margin convex; 10–13 (male) or 9–12 (female) antenna I lobes reaching to antenna II flagellomeres IV–VII (male) or II–III (female); 10–12 (male) or 10–11 (female) antenna II flagellomeres; 19–20 complete thorax segments; 17–29 telsonic spines, anterior spines short and conical with usually two larger spines interspersed, posterior spines increasing in size and aciculate; 5–12 furcal setae.

Differential diagnosis

Ozestheria weeksi 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. pilbarensis sp. nov., and differentiating these species can be difficult. Ozestheria weeksi differs by having fewer antenna II flagellomeres than most other of the abovementioned species and by the shape of the female rostrum with the dorsally strongly protruding (globose) anterior margin. The latter is also present in O. marthae , O. selmae and O. bourkensis , but less strongly pronounced.

Etymology

The species is named after US zoologist Stephen C. Weeks, honoring his contributions to clam shrimp biology. The described specimens were reared and documented in Stephen’s lab.

Type material

Holotype

AUSTRALIA – Western Australia • ♂; Cullimbin Reserve, Shire of Dowerin via Stout Rd , Pool 5; 30°50.972′ S, 117°14.751′ E; 7 Mar. 2007; A. Calabrese leg.; cultivated from sediment 2022 by M. Hethke and S. Weeks; GenBank no: PQ427022( COI); NHMW-ZOO-CR-28187.

Paratypes

AUSTRALIA – Western Australia • 9 ♂♂, 11 ♀♀; same data as for holotype; GenBank nos: PQ427019– PQ427021, PQ427023–PQ427029, PQ427032–PQ427037, PQ427039 ( COI); NHMW-ZOO-CR-28176 to NHMW-ZOO-CR-28186, NHMW-ZOO-CR-28188 to NHMW-ZOO-CR-28196 .

Other material examined

AUSTRALIA – Western Australia • 4 ♂♂; Woomberna Rock on Balladonia Station ; 32°17′01.7″ S, 123°33′22.9″ E; 14 Aug. 2009; B.V. Timms leg.; AM P.91698, P.91699, P.91703, P.91705 • 1 ♂, 1 ♀; claypan at King Rocks Rd , 33 km NE of Hyden; 32°19′37.9″ S, 119°6′8.17″ E; 14 Oct. 2008; C. Francis leg.; WAM C77989 , C80225 • 1 ♂; claypan at King Rocks Rd , 33 km NE of Hyden; 32°19′37.9″ S, 119°6′8.17″ E; 14 Oct. 2008; C. Francis leg.; NHMW-ZOO-CR-29000 .

Type locality

Western Australia, Cullimbin Reserve, Shire of Dowerin via Stout Rd, Pool5, 30°50.972′ S, 117°14.751′E.

Description

Males

CARAPACE ( Fig. 50a, c–d). Length 4.9–6.0 mm (HT: 5.5 mm, mean: 5.4 mm), height 2.8–3.4 (HT: 3.2 mm, mean: 3.1 mm). Coloration white-yellowish to yellow-orange, crowded growth bands lighter. 17–40 (HT: 20, mean: 24) growth lines, 14–24 (HT: 16, mean: 17) widely spaced and 3–22 (HT: 4, mean: 7) crowded.

CARAPACE SHAPE. Dorsal margin straight, distinct dorso-posterior corner. Posterior margin broadly rounded, suboval, supracurvate to equicurvate (b/H 0.44–0.50, HT: 0.44, mean: 0.47). Ventral margin nearly straight to slightly rounded. Umbo position submedian (Cr/L 0.20–0.27, HT: 0.25, mean: 0.25).

CARAPACE ORNAMENTATION ( Fig. 50e–g). Larval valve and growth bands in dorsal parts of carapace punctate or granular (punctate under SEM). In successive growth bands, poorly defined, irregular lirae forming ventrally between punctae; lirae increase in length in following growth bands. Lirae become longer in following growth bands, extending across whole growth bands. Lirae subparallel, anastomosing and intermittent; usually more pronounced and less anastomosing ventrally within growth bands. Crowded growth bands with short, parallel, pronounced lirae in some individuals. Concentric ridges raised and punctate. Setae spiniform, usually only few on carapace; setae of the outer most 2–3 growth bands often dense and longer. Setal pores in single row along all growth lines.

HEAD ( Fig. 50h). Condyle long, distally acute; occipital notch narrow. Condyle with weakly developed or without anterobasal hump (HT: present). Margin between condyle and ocular tubercle straight to weakly concave. Ocular tubercle well developed, forming nearly rectangular to nearly straight (~100°– 180°) angle with rostrum. Anterior margin of rostrum weakly convex. Apex rounded, nearly rectangular. Ventral margin of rostrum anteriorly convex, then straight or weakly concave. Naupliar eye subtriangular. Antenna I long with 9–14 lobes (HT: 11; mean: 12), reaching to antenna II flagellomeres IV–VII (HT: VII; mean: VI). Antenna II with 10–12 flagellomeres (HT: 11; mean: 11).

THORAX. 20–21 (HT: 21; mean: 21) segments, 19–20 (HT: 20; mean: 20) thoracopod-bearing and one (HT: one) posterior limbless segment not reaching dorsal margin. The majority of thoracopod-bearing segments with numerous spines and setae on dorsal extensions.

THORACOPOD III (only NHMW-CR-28187; Fig. 50l). Endite I short and curved dorsally. Endites II–V broad, decreasing in size. Endite V palp two-segmented, basal segment slightly shorter than endopod. Exopod ventral extension subequal in extension to endopod, dorsal extension wide, narrowing distally, overreaching epipod. Epipod long, cylindrical.

TELSON ( Fig. 50j). 15–29 spines (HT: 20; mean: 21). First (anterior) spine enlarged. Spines on anterior ½ to ¾ of telson short, conical, subequal in length; following spines thinner, elongate, aciculate, in some individuals increasing in size posteriorly. Two larger spines interspersed (usually among conical spines or at transition to aciculate spines). Dorsal margin straight or weakly concave. Right terminal claw more strongly curved than left.

FURCA ( Fig. 50j). Proximally with dorsomedial longitudinal row of 6–12 (HT: 6, mean: 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. 50b) length 5.0– 5.8 mm (mean: 5.3 mm), height 2.8– 3.4 mm (mean: 3.1 mm); 17–34 (mean: 19) growth lines, 12–19 (mean: 16) widely spaced and 1–15 (mean: 3) crowded; Cr/L 0.23–0.27 and b/H 0.46–0.50. Ocular tubercle weakly developed. Anterior margin of rostrum concave, dorsally strongly protruding, globose; apex drawn out into acute tip, with rectangular angle; ventral margin convex ( Fig. 50i). Antenna I with 9–12 small lobes (mean: 11), lobes smaller than in males; reaching to antenna II flagellomeres II–III (mean: III). Antenna II with 10–11 flagellomeres (mean: 11). Telson with 17–27 (mean: 21) dorsal spines; left and right terminal claws equally curved or right slightly stronger curved ( Fig. 50k). Furca with 5–7 setae (mean: 6).

Distribution ( Fig. 50m)

Ozestheria weeksi sp. nov. is known only from a single locality in southwestern Western Australia

Remarks

Ozestheria weeksi sp. nov. is part of a group of five very closely related species; see remarks on O. typica comb. nov. for details. The carapace shape of Ozestheria weeksi ( Fig. 6) is distinct from that of many other species and overlaps partly with those of O. jiangi sp. nov., O. minor comb. nov., O. fuersichi sp. nov., 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. barcaldinensis sp. nov., O. quinlanae sp. nov., O. echidna sp. nov., and O. pilbarensis sp. nov.