Ozestheria marthae, 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 : 89-92

Ozestheria marthae sp. nov.

urn:lsid:zoobank.org:act:3099BC5D-8719-4618-A89B-188ED6DBFE7A

Fig. 28

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

Diagnosis

Ozestheria marthae sp. nov. is characterized by a long condyle and a narrow occipital notch; carapace ornamentation dorsally on carapace finely punctate to finely reticulated (ornamentation may appear granular rather than punctate), from about mid-carapace fine lirae forming between punctae, lirae become more pronounced (still rather inconspicuous) with progressing growth bands; male rostrum with weakly convex anterior margin, apex weakly rounded with acute angle (~70°), ventral margin anteriorly with small convex protrusion; female rostrum anterior margin slightly concave with distinct rounded bulge at fronto-dorsal corner, apex pointed, drawn out into acute tip, ventral margin weakly concave; 11–17 (male) or 10–15 (female) antenna I lobes reaching to antenna II flagellomeres IV–VII (male) or II–IV (female); 10–13 (male) or 9–12 (female) antenna II flagellomeres; 19–22 complete thorax segments; 15–27 telsonic spines, anterior spines conical with 2–3 larger spines interspersed (usually in middle of telson and the other among the last four spines), posterior spines thinner and drawn out; 3–8 furcal setae.

Differential diagnosis

Ozestheria marthae 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 subparallel and reticulating lirae), except from O. cancellata comb. nov., O. minor comb. nov., O. typica comb. nov., O. fuersichi sp. nov., O. jonnae 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, though in O. marthae lirae are intermittent and nodular (best seen under SEM). Ozestheria marthae differs by the presence of a fronto-dorsal bulge at the anterior margin of the female rostrum from all of these species except O. weeksi . Ozestheria weeksi has fewer complete thorax segments and fewer antenna I lobes (male and females). Furthermore, O. minor , O. typica , O. bourkensis , O. selmae , O. radiata , and O. beleriandensis can be differentiated by having at least the posterior half of the telsonic spines long, elongated and aciculate.

Etymology

The species is named after Martha Schwentner, the oldest daughter of MS.

Type material

Holotype

AUSTRALIA – New South Wales • ♂; Lake Cooltralantra, via Berridale ; 36°15′56.8″ S, 148°53′16.4″ E; 2 Mar. 2010; M. Schwentner and C.Sieves leg.; GenBank no: KJ705888 ( COI); AM P.91660.

Paratypes

AUSTRALIA – New South Wales • 1 ♂, 1 ♀; same data as for holotype; GenBank nos: KJ705887, KJ705889 ( COI); AM P.91659, P.91661 • 1 ♂; same data as for holotype; GenBank no: KJ705890 ( COI); NHMW-ZOO-CR-28485 .

Other material examined

AUSTRALIA – New South Wales • 2 ♂♂, 2 ♀♀; claypan on Snowleigh Station ; 36°40′52.6″ S, 149°00′00.5″ E; 13 Mar. 2010; M. Schwentner and C. Sieves leg.; AM P.91651 to P.91654 • 5 ♀♀; claypan on Snowleigh Station ; 36°40′5″ S, 148°00′01″ E; 12 Apr. 2012; B.V. Timms leg.; AM P.91673

to P.91677 • 4 ♂♂; Avon Lake , Bungarby; 36°37′04.2″ S, 149°02′58.4″ E; 14 Mar. 2010; M. Schwentner and C. Sieves leg.; AM P.91655 to P.91658 .

Additional material (not examined)

AUSTRALIA – New South Wales • 5 juvs; Killmacoola Lagoon ; 36°16′23.9″ S, 148°55′53.3″ E; 2 Mar. 2010; M. Schwentner and C. Sieves leg.; AM P.91663 to P.91667 • 5 juvs; Salt Lake, Cooma ; 36°21′47.8″ S, 148°57′10.7″ E; 3 Mar. 2010; M. Schwentner and C. Sieves leg.; AM P.91668 to P.91672 .

Type locality

New South Wales, Lake Cooltralantra, via Berridale, 36°15′56.8″ S, 148°53′16.4″ E.

Description

Males CARAPACE ( Fig. 28a, c–d). Length 4.3–5.8 mm (HT: 5.8 mm), height 2.6–3.5 mm (HT: 3.3 mm). Coloration light orange-yellowish to dark orange/ocher, crowded growth band lighter, whitish. 13–19

(HT: 15) growth lines, 13–19 (HT: 15) widely spaced and none to three (HT: none) crowded.

CARAPACE SHAPE. Dorsal margin straight, distinct dorso-posterior corner. Posterior margin broadly rounded, suboval, equicurvate (b/H 0.47–0.53, HT: 0.51). Ventral margin broadly rounded. Umbo position anterior (Cr/L 0.21–0.25, HT: 0.24).

CARAPACE ORNAMENTATION ( Fig. 28e–g). Larval valve and following growth bands granular (finely punctate to finely reticulated under SEM). From about mid-carapace, shallow, irregular, fine lirae appear between punctae; becoming stronger, subparallel and conflating lirae on growth bands of later ontogenetic stages (lirae intermittent and nodular under SEM). On the posterior part of carapace, some lirae ‘disappearing’ before growth line, leading to a reduced liral density and irregular liral spacing. Crowded growth bands nodular with short lirae. Concentric ridges shallow and punctate (only seen under SEM). Setae filiform, preferentially preserved in the median and posterior parts of the carapace; under SEM setal pores in a single row and widely spaced.

HEAD ( Fig. 28h–i). Condyle long, distally acute; occipital notch narrow. Condyle with weak anterobasal hump in a few individuals (usually absent). Margin between condyle and ocular tubercle straight to slightly concave (HT: straight). Ocular tubercle weakly developed, forming obtuse (~150–180°) angle with rostrum, rostrum protruding from head. Anterior margin of rostrum weakly convex. Ventral margin of rostrum with or without small anterior notch followed by small convex protrusion; apex weakly rounded, acute (~70°). Naupliar eye roundish-oval to subtriangular with rounded edges. Antenna I long with 11–17 lobes (HT: 12), reaching to antenna II flagellomeres IV–VII (HT: V). Antenna II with 10–13 flagellomeres (HT: 11).

THORAX. 20–23 (HT: 22) segments, 19–22 (HT: 21) 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 ~8 th last segment). Spines short and stout, in posterior segments central spines stouter but shorter.

THORACOPOD III (only P.91660; Fig. 28m). Endite I short and curved dorsally. Endites II–V broad, decreasing in size. Endite V palp two-segmented, basal segment subequal to endopod. Exopod ventral extension shorter than endopod; dorsal extension wide, narrowing distally, overreaching epipod. Epipod long, cylindric.

TELSON ( Fig. 28k–l). 15–22 spines (HT: 20). First (anterior) spine enlarged. Spines subequal in length, thin, conical, posteriormost spines thinner and drawn out. Two (rarely three) larger spines (~2× in size) interspersed, one about half-length of telson and one posteriorly (usually among last four spines). Dorsal margin straight to slightly convex, posteriorly slightly concavely curved. Right terminal claw more strongly curved than left.

FURCA ( Fig. 28k–l). Proximally with dorsomedial longitudinal row of 4–8 (HT: 6) setae, row ending distally in a single conical spine. Distal part ½–⅔ of furcal length, with numerous small denticles.

Females

Overall appearance as in males. Carapace ( Fig. 28b) length 4.9–6.6 mm, height 3.0–4.1. 12–22 growth lines, 11–19 widely spaced and none to three crowded, Cr/L 0.22–0.25 and b/H 0.43–0.57. Rostrum with distinct rounded bulge at fronto-dorsal corner, anterior margin slightly concave; apex pointed, drawn out into acute tip, which is slightly antero-dorsally curved, ventral margin weakly concave ( Fig. 28j). Antenna I with 10–15 small lobes, lobes smaller than in males; reaching to antenna II flagellomeres II–IV. Antenna II with 9–12 flagellomeres. 21–23 segments, 21–22 thoracopod-bearing and none to two posterior limb-less segments not reaching dorsal margin. Telson with 18–27 dorsal spines; left and right terminal claws equally curved. Furca with 3–6 setae.

Distribution ( Fig. 28n)

Ozestheria marthae sp. nov. is known only from the tablelands around Cooma and Berridale in southern New South Wales, where it occurs in a variety of habitats including freshwater and hyposaline lakes as well as claypans. It is possible that it occurs more widely in this mountainous area.

Remarks

The carapace shape of Ozestheria marthae sp. nov. ( Fig. 6) is distinct from that of most other species and overlaps 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. (marginally), O. selmae sp. nov., O. cancellata comb. nov., O. weeksi sp. nov., O. quinlanae sp. nov., and O. pilbarensis sp. nov.