Ozestheria typica ( Spencer & Hall, 1896 ), 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 : 154-159

Ozestheria typica ( Spencer & Hall, 1896) comb. nov.

Figs 48–49

Estheria packardi var. typica Spencer & Hall, 1896: 237 , fig. 21.

Caenestheriella packardi var. typica – Daday 1914: 120.

Cyzicus packardi var. typica – Brtek 1997: 48.

Ozestheria packardi (in part) – Richter & Timms 2005: 347. — Rogers 2020: 24.

Ozestheria sp. Q5 – Schwentner et al. 2015a: figs 2, 6; 2020: figs 1–2. — Hethke et al. 2023: fig. 11.

Diagnosis

Ozestheria typica comb. 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; male rostrum with weakly convex anterior margin, apex weakly rounded with ~70–90° angle, ventral margin posteriorly weakly convex (rarely straight) with slight notch close to apex; female rostrum anterior margin short, slightly convex to straight, apex rectangular and drawn out into small and acute tip, ventral margin straight to strongly convex; 10– 14 (male) or 8–14 (female) antenna I lobes reaching to antenna II flagellomeres V–X (male) or II–V (female); 8–13 (male) or 8–12 (female) antenna II flagellomeres; 19–20 complete thorax segments; 18– 32 large telsonic spines, anterior spines small and conical, posterior spines thinner, drawn out, aciculate and increasing in size posteriorly, one larger cone-shape and one larger aciculate spine interspersed (rarely up to three larger spines each interspersed); 1–14 furcal setae.

Differential diagnosis

Ozestheria typica comb. 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. fuersichi sp. 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 typica differs from O. cancellata , O. fuersichi , O. jonnae , O. marthae , O. rincewindi , O. barcaldinensis , O. ngamurru , O. quinlanae , O. glabra , O. pilbarensis and O. weeksi in having at least the posterior half of the telsonic spines long, elongate and aciculate (in the other species fewer telsonic spines are long and aciculate and more spines shorter and conical) and by the shape of the female rostrum (straight anterior margin and apex drawn out into a minutely pointed tip). In O. minor the line between condyle and ocular tubercle is straight and the female antennae I and II have more lobes and flagellomeres. Ozestheria bourkensis generally has fewer telsonic spines and the angle between the ocular tubercle and rostrum is nearly rectangular in males (vs obtuse in O. typica ). Ozestheria selmae has a larger carapace (length 3.7–7.0 vs 2.8–5.5; while having similar numbers of growth lines), more complete thorax segments and the apex of the female rostrum is not as minutely pointed. Ozestheria beleriandensis has a more rounded ventral carapace margin and a slightly longer carapace. Ozestheria radiata has a larger carapace and the apex of the male rostrum is more strongly rounded.

Type material

Syntypes

AUSTRALIA – Northern Territory or South Australia • 3 ♂♂, 4 ♀♀, 1 spec.; Charlotte Waters Central Australia; Horn Expedition leg.; the material was given to the collections of MV by O.A. Sayce 25 Jul. 1911, the syntypes probably dried out in the past and are in rather poor condition, the soft bodies are greatly distorted and the corresponding features could be inferred only in a few instances; MV J54046 .

Other material examined

AUSTRALIA – New South Wales • 2 ♀♀; E of Lake Lauradale , 29°51′22″ S, 145°38′49″ E; 29 Mar. 2009; M. Schwentner and B.V. Timms leg.; AM P.91679, P.91678 • 1 ♂; E of Lake Lauradale ; 29°51′22″ S, 145°38′49″ E; 18 Jan. 2010; M. Schwentner and B.V. Timms leg.; AM P.91753 • 4 ♂♂; Muella Station, Lower Lake Eliza ; 29°25′28.9″ S, 145°03′41.8″ E; 20 Jan. 2010; M. Schwentner and B.V. Timms leg.; AM P.91754 to P.91757 • 1 ♂, 6 ♀♀; N of Wyandra ; 27°11′03.2″ S, 145°59′41.2″ E; 17 Feb. 2010; M. Schwentner, C. Sieves and B.V. Timms leg.; AM P.91747 to P.91750, P.91695 to P.91697 . – Northern Territory • 3 ♂♂, 1 ♀; Ilpara claypans near Alice Springs ; 23°45′15.8″ S, 133°47′52.7″ E; 27 Jan. 2010; M. Schwentner and B.V. Timms leg.; AM P.91681 to P.91684 . – Queensland • 2 ♂♂, 1 ♀; grassy turbid swamp; 27°41′52.4″ S, 146°45′44.7″ E; 18 Feb. 2010; M. Schwentner, C. Sieves and B.V. Timms leg.; AM P.91751, P91752, P.91758 • 1 ♀; Currawinya National Park , well-vegetated claypan; 28°47′19.4″ S, 144°17′43.3″ E; 24 Feb. 2011; M. Schwentner, S. Richter and B.V. Timms leg.; AM P.91742 • 1 ♂, 2 ♀♀; Currawinya National Park , Triops claypan; 28°47′14.9″ S, 144°17′49.1″ E; 24 Feb. 2011; M. Schwentner, S. Richter and B.V. Timms leg.; AM P.91743 to P.91745 • 1 ♂; Currawinya National Park, claypan halfway on northern fence of Bilby enclosure; 28°52′12.8″ S, 144°21′52.1″ E; 25 Feb. 2011; M. Schwentner, S. Richter and B.V. Timms leg.; AM P.91741 • 2 ♂♂, 1 ♀; Gidgee claypan 9 km from Tenham Station ; 25°41′02.4″ S, 143°00′59.4″ E; 28 Feb. 2011; M. Schwentner and B.V. Timms leg.; AM P.91737 to P.91739 • 1 ♂; same data as for preceding; NHMW-ZOO-CR-28492 . – South Australia • 1 ♂, 3 ♀♀; old small dugout 105 km E of Marla ; 27°10′00.2″ S, 134°33′07.2″ E; 11 Mar. 2011; M. Schwentner and B.V. Timms leg.; AM P.91723 to P.91725, P.91766 • 4 ♂♂, 1 ♀; daisy claypan 106 km E of Marla ; 27°10′02.2″ S, 134°33′30.7″ E; 11 Mar. 2011; M. Schwentner and B.V. Timms leg.; AM P.91727 to P.91730 • 3 ♂♂, 1 ♀; daisy claypan 106 km E of Marla ; 27°10′02.2″ S, 134°33′30.7″ E; 11 Mar. 2011; M. Schwentner and B.V. Timms leg.; AM P.91719 to P.91722 • 1 ♀; dead shrub dam 1 km N of William Creek ; 28°54′14.0″ S, 136°19′35.4″ E; 12 Mar. 2011; M. Schwentner and B.V. Timms leg.; AM P.91718 . – Western Australia • 1 ♀; roadside scrape, 12 km W of Paynes Find ; 29°17′07″ S, 117°34′01″ E; 20 Aug. 2011; B.V. Timms leg.; AM P.91708 .

Additional material (not examined)

AUSTRALIA – New South Wales • 5 juvs; 25 km E of Engonia ; 29°15′29.7″ S, 146°05′37.4″ E; 21 Jan. 2010; M. Schwentner and B.V. Timms leg.; AM P.91759 to P.91763 • 3 juvs; Bloodwood Station, turbid Marsilea swamp S of Junction Pool; 29°31′33.3″ S, 144°50′23.6″ E; 23 Feb. 2011; M. Schwentner, S. Richter and B.V. Timms leg.; AM P.91746, P.91764, P.91765 .

Type locality

Spencer & Hall (1896) did not specify a type locality but generally stated where they collected O. packardi and its newly described varieties as “Common in water-holes along the Finke and its tributaries, also in the Macumba and Stevenson Rivers”. The label of the syntype collection states “Charlotte Waters Central Australia ”.

Description

Males CARAPACE ( Fig. 48a–d, f). Length 3.3–4.6 mm (ST: 3.3–3.7 mm, mean: 3.8 mm), height 2.0–2.6 (ST:

1.9–2.3 mm, mean: 2.3 mm). Coloration orange to reddish-brown or light brownish, coloration lighter ventrally on carapace; outer margin whitish. 14–48 (ST: 14–16, mean: 25) growth lines, 11–19 (ST: 11–12, mean: 15) widely spaced and 3–30 (ST: 3–5, mean: 11) crowded.

CARAPACE SHAPE. Dorsal margin straight, rounded or distinct dorso-posterior corner. Posterior margin broadly rounded, suboval, equicurvate to infracurvate (b/H 0.46–0.57, ST: 0.46, mean: 0.51) with greatest extension at or below midline. Ventral margin nearly straight. Umbo position submedian (Cr/L 0.26–0.35, ST: 0.26–0.27, mean: 0.29).

CARAPACE ORNAMENTATION ( Fig. 48g –k). Larval valve and directly following growth bands finely punctate (may appear granular). Within following growth bands, dorsal parts punctate, with shallow and strongly anastomosing lirae forming ventrally within growth band (the onset and extent of lirae differs markedly between individuals; in some individuals lirae appear to reach across full growth bands also dorsally on carapace). Lirae becoming more pronounced in progressing ontogenetic stages and posteriorly. From mid-dorsal carapace, lirae pronounced and less strongly anastomosing (especially posteriorly on carapace). Crowded growth bands often too closely set for ornamentation, otherwise well defined, parallel lirae. Concentric ridges shallow. Setae mostly filiform (rarely spiniform); preferentially preserved on ventral and posterior parts of the carapace if any preserved. Setal pores in single row along all growth lines.

HEAD ( Fig. 49a–c). Condyle long, distally acute; occipital notch narrow. Condyle with anterobasal hump. Margin between condyle and ocular tubercle slightly to strongly concave. Ocular tubercle well developed, forming obtuse angle with rostrum, which can be nearly straight or close to rectangular (ranging from ~100–170°). Rostrum dorsally protruding from head. Anterior margin of rostrum weakly convex. Ventral margin of rostrum with slight notch close to apex, posteriorly weakly convex, rarely straight; apex weakly rounded with ~70–90° angle (due to following notch, the overall angle ~60–70°). Rostrum shape subtrapezoidal. Naupliar eye usually relatively short and stout, triangular, anterior vertex sometimes widened and rounded. Antenna I long with 10–14 lobes (mean: 12), reaching to antenna II flagellomeres V–X (mean: VIII). Antenna II with 8–13 flagellomeres (mean: 11).

THORAX. 19–21 (mean: 20) segments, 19–20 (mean: 19) thoracopod-bearing and none to one posterior limbless segment not reaching dorsal margin. Last ~13 thoracopod-bearing segments with spine and/ or setae bearing dorsal extensions. Dorsal extensions increasing in size posteriorly over successive segments (until ~10 th last segment). Most segments with 5–7 spines or setae, posterior segments with three or one stout spine.

THORACOPOD III (only P.91738; Fig. 49f). Endite I short and curved dorsally. Endites II–V broad, decreasing in size. Endite V palp two-segmented, basal segment subequal in length to endopod. Exopod ventral extension shorter in extension to endopod, dorsal extension wide, narrowing distally, overreaching epipod. Epipod long, cylindric.

TELSON ( Fig. 49h–i). 18–30 spines (ST: 18–20; mean: 25). First (anterior) spine greatly enlarged. Following spines subequal in length, anterior ~½ of spines small and conical, posterior spines thinner, drawn out, aciculate and increasing in size posteriorly. Usually, one larger conical and one larger aciculate spine interspersed, rarely up to three larger spines each interspersed. Dorsal margin either straight or anteriorly convex (~1/5–⅓ of length) and posteriorly concavely curved. Right terminal claw more strongly curved than left.

FURCA ( Fig. 49h–i). Proximally with dorsomedial longitudinal row of 1–14 (mean: 6) setae, row ending distally in a single conical spine. Distal part ½–⅔ of furcal length, weakly to strongly curved, with numerous small denticles.

Females

Overall appearance as in males. Carapace ( Fig. 48e) length 2.8–5.5 mm (ST: 2.8–3.8 mm; mean: 4.2 mm), height 1.8–3.3 mm (ST: 1.8–2.2 mm; mean: 2.6 mm); 16–40 (ST: 16–17, mean: 28) growth lines, 12–28 (ST: 12–13, mean: 17) widely spaced and 0–32 (mean: 11) crowded; Cr/L 0.25–0.30 (mean: 0.28) and b/H 0.48–0.57 (mean 0.53). Rostrum clearly protruding dorsally, anterior margin short, slightly convex to straight; apex pointed, drawn out into small, acute tip, overall rectangular; ventral margin straight to strongly convex, lacking anterior notch; overall rostrum shape trapezoidal ( Fig. 49d–e). Antenna I with 8–14 small lobes (mean: 10), lobes smaller than in males, but usually clearly demarcated from each other; reaching to antenna II flagellomeres II–V (mean: IV). Antenna II with 8–12 flagellomeres (mean: 11). 19–21 (mean: 20) segments, 19–20 (mean: 19) thoracopod-bearing and none to one posterior limbless segment not reaching dorsal margin. Telson with 20–32 (ST: 27, mean: 26) dorsal spines; difference in curvature of left and right terminal claws less pronounced than in males ( Fig. 49g). Furca with 2–6 setae (mean: 5).

Distribution ( Fig. 49j)

Ozestheria typica comb. nov. is one of the most widely distributed Australian spinicaudatan species. It has been recorded in eastern Australia (especially in the northern Murray-Darling Basin in northern New South Wales and southern Queensland), central Australia (northern South Australia and southern Northern Territory, e.g., close to Alice Springs) as well as Western Australia (close to Paynes Find). It occurs predominately in turbid claypans, dugouts or swamps.

Remarks

Ozestheria typica comb. nov. was originally described as one of three varieties of O. packardi by Spencer & Hall (1896). Previous workers (e.g., Richter & Timms 2005; Rogers 2020) have synonymized these varieties with O. packardi . However, the large cryptic species diversity within O. packardi , which was revealed by molecular genetic analyses ( Schwentner et al. 2015a), strongly suggested that O. typica and the other varieties represent valid species. A comparison between the syntypes and the genetically delimited species strongly suggests that O. typica corresponds to Ozestheria sp. Q5 of Schwentner et al. (2015a). This correspondence includes in particular details of the carapace ornamentation and shape, the telson spination pattern and the rostrum shapes (especially the minutely pointed female apex) as well as the geographic distribution.

In the geometric morphometric analyses of carapace shape ( Fig. 6), O. typica comb. nov. is distinct from that of most other species and overlaps partly with those of O. jiangi sp. nov., O. minor comb. nov., O. selmae sp. nov., O. radiata sp. nov., O. bourkensis sp. nov., O. ngamurru sp. nov., O. beleriandensis sp. nov., O. carnegiensis sp. nov. and O. echidna sp. nov. In the classification of type specimens, the mean shape of the syntypes of O. typica (Supp. file 2_4.6) was most similar to O. sp. Q5 (44.5% probability, 0.26 typicality), followed by the closely related species O. sp. Q3 ( O. selmae ; 25.2% probability, 0.27 typicality) and O. sp. Q4 ( O. radiata ; 20.1% probability, 0.30 typicality).

The syntypes of O. typica were neither explicitly marked as types nor as O. typica . Based on the labels and notes associated with these specimens, they were identified as Caenestherialla packardi (= O. packardi ) by Sayce (1911) and Timms (2008). However, the collection details of these specimens correspond to the material from the Horn Expedition, which was collected and studied by Spencer & Hall. In combination with the morphological congruence, it is highly likely that these are the original type specimens of O. typica .

Schwentner et al. (2015a) reported five very closely related species (termed Ozestheria sp. Q1–Q5), which are probably reproductively separated. While one of these represents O. typica comb. nov. (= O. sp. Q5), three others are formally described as new species herein: O. weeksi sp. nov. (= O. sp. Q2), O. selmae sp. nov. (= O. sp. Q3) and O. radiata sp. nov. (= O. sp. Q4). Of O. sp. Q1, only three individuals were available, of which two are probably not fully mature. As this does not allow a proper assessment of the species’ morphological variability and its differentiation from the other closely related species, we decided to not formally name and describe O. sp. Q1 herein.