Ozestheria lutraria ( Brady, 1886 )

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 : 79-85

Ozestheria lutraria ( Brady, 1886)

Figs 25–26

Estheria lutraria Brady, 1886: 85 , fig. b.

Estheria dictyon Spencer & Hall, 1896: 236 , fig. 20.

Estheria lutraria – Spencer & Hall 1896: 234–235, fig. 20. — Sayce 1903: 254, 256, fig. 35. — Henry 1924: 121–122, 134.

Estheria dictyon – Sayce 1903: 255–256, fig. 36a. — Henry 1924: 122, 134.

Cyzicus dictyon – Wolf 1911: 254. — Dakin 1911: 295.

Cyzicus lutraria – Wolf 1911: 254. — Dakin 1911: 295.

? Caenestheria dictyon – Daday 1914: 105.

Caenestheria lutraria – Daday 1914: 56, 90–92, fig.11. — Richter & Timms 2005: 344 .

Eocyzicus lutrarius – Brtek 1997: 49.

Ozestheria sp. C – Schwentner et al. 2015a: figs 2, 6. — Hethke et al. 2023: fig. 10.

Caenestheria dictyon – Richter & Timms 2005: 346 .

Ozestheria lutraria – Schwentner et al. 2020: 1–2. — Rogers 2020: 23–24 .

Ozestheria dictyon – Schwentner et al. 2020: figs 1–2. — Rogers 2020: 23 .

Diagnosis

Ozestheria lutraria is characterized by a short condyle and a wide occipital notch; straight ventral margin of carapace and strongly supracurvate posterior margin; carapace ornamentation with large, well-developed polygonal reticulations, each polygon without secondary ornamentation (best seen under SEM); male rostrum with convex anterior margin, apex rounded with acute angle, ventral margin strongly concave, pointing apex downwards; female rostrum anterior margin weakly convex, apex pointed with weakly or strongly drawn-out tip, ventral margin strongly concave; 14–24 (male) or 14–20 (female) antenna I lobes reaching to antenna II flagellomeres III–VIII (male) or III–VIII (female); 13– 17 (male) or 14–17 (female) antenna II flagellomeres; 24–27 complete thorax segments; 7–20 (adults usually ~11, juveniles more) usually very small and widely spaced, conical spines (spines in juveniles larger); 8–17 furcal setae.

Differential diagnosis

Ozestheria lutraria can be easily differentiated. It is the largest growing species (up to nearly 14 mm). The most characteristic features are the carapace shape (oblong, oval), the carapace ornamentation (large polygonal reticulations on all growth bands of the primary growth phase), the largest number of thorax segments (25–28) and telson spination. The morphologically most similar species are O. rufa , O. paralutraria sp. nov., O. sarsii and O. christiani sp. nov. Ozestheria sarsii differs by the shape of the male and female rostrum (i.e., rounded apex), the lower number of thorax segments and antennal lobes, and the polygons of carapace ornamentation of O. christiani are partly intermittent. Ozestheria rufa can be differentiated by the ornamentation (not all wide growth bands with polygonal reticulations) and the shape of the female rostrum (males currently unknown for O. rufa ), whose ventral margin is not as strongly concave and whose apex is pointed, but not drawn out into an elongated tip. O. paralutraria can be differentiated by its fewer thoracic segments (24 vs 25–27 complete segments), more telsonic spines (16–18 in O. paralutraria , whereas O. lutraria rarely has more than 15), fewer setae on the carapace (in a single row vs in two rows along each concentric ridge in O. lutraria ; best seen under SEM) and by length of the carapace (up to 9 mm vs> 10 mm in O. lutraria ). Juveniles of O. lutraria may be confused with other species as their telsonic spines are unusually large and prominent, but the carapace shape is identical to those of the adults.

Type material

Neotype (here designated)

AUSTRALIA – Queensland • 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.; GenBank no: KJ705517 ( COI); AM P.91288.

Other material examined

AUSTRALIA – New South Wales • 1 ♂; E of Lake Lauradale ; 29°51′22″ S, 145°38′49″ E; 29 Mar. 2009; M. Schwentner and B.V. Timms leg.; AM P.89647 • 1 ♂, 1 ♀; claypan-like West of Engonia ; 29°18′32.8″ S, 145°44′06.9″ E; 21 Jan. 2010; M. Schwentner and B.V. Timms leg.; AM P.91353, P.91354 • 3 ♂♂, 1 ♀; Bloodwood Station, Georges Tank ; 29°32′57.4″ S, 14°48′52.1″ E; 20 Jan. 2010; B.V. Timms leg.; AM P.91378, P.91366 to P.91369 • 4 ♂♂, 2 ♀♀; 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.82575, P.82576, P.91345 to P.91347, P.91352 . – Northern Territory • 1 juv.; Ilparpa Claypan near Alice Springs ; 13 Jan. 2010; J Van Der Reijden leg.; AM P.91378 • 3 ♂♂, 1 ♀; Ilparpa 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.91283, P.91341 to P.91343 . – Queensland • 2 ♂♂, 1 ♀; same data as for neotype; GenBank nos: KJ705514, KJ705515, KJ705518 ( COI); AM P.91285, P.91286, P.91289 • 1 ♂; same data as for neotype; GenBank no: KJ705516 ( COI); NHMW-ZOO-CR-28488 • 2 ♂♂; Currawinya National Park , Triops claypan; 28°47′14.9″ S, 144°17′49.1″ E; 24 Feb. 2011; M. Schwentner and B.V. Timms leg.; AM P.91314, P.91315 • 2 ♂♂, 2 ♀♀; cane grass swamp 75 km E of Wyandra ; 27°23′03.5″ S, 146°36′33.7″ E; 17 Feb. 2010; M. Schwentner and B.V. Timms leg.; AM P.91355 to P.91358 • 2 ♂♂; grassy turbid swamp 10 km from Bollon road junction; 27°41′52.4″ S, 146°45′44.7″ E; 18 Feb. 2010; M. Schwentner, C. Sieves and B.V. Timms leg.; AM P.91375, P.91376 • 3 juvs; black box claypan 58 km from Hungerford Road ; 28°50′23.1″ S, 143°53′46.0″ E; 26 Feb. 2011; M. Schwentner, S. Richter and B.V. Timms leg.; AM P.91311 to P.91313 • 1 ♂, 4 ♂♂; claypan 46 km E of Thargomindah ; 28°05′05.1″ S, 144°14′54.7″ E; 27 Feb. 2011; M. Schwentner and B.V. Timms leg.; AM P.91336 to P.91340 • 2 ♂♂, 2 ♀♀; claypan spring complex edge of Simpson Desert ; 23°34′45.5″ S, 138°40′07.0″ E; 6 Nov. 2010; A. Emmett leg.; AM P.91306 to P.91309 . – South Australia • 8 juvs; “South Australia”; syntypes of Ozestheria dictyon ; MV J53359 • 4 ♂♂; vegetated stony dugout 34 km N of Marla ; 27°05′26.8″ S, 133°28′16.2″ E; 10 Mar. 2011; M. Schwentner and B.V. Timms leg.; AM P.91316, P.91319 to P.91322 • 1 ♂, 2 ♀♀; 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.91302, P.91304, P.91305 • 1 ♂, 1 ♀; cane grass swamp 44 km W of Oodnadatta ; 27°20′07.1″ S, 135°07′47.7″ E; 11 Mar. 2011; M. Schwentner and B.V. Timms leg.; AM P.91323, P.91325 • 2 ♂♂; Fogatys Claypan 60 km N of Oodnadatta; 27°03′21.4″ S, 135°14′57.2″ E; 11 Mar. 2011; M. Schwentner and B.V. Timms leg.; AM P.91295, P.91298 • 1 ♂, 4 ♀♀; claypan 16 km north Williams Creek ; 28°52′03.6″ S, 136°11′08.6″ E; 12 Mar. 2011; M. Schwentner and B.V. Timms leg.; AM P.91326 to P.91330 • 2 ♂♂, 2 ♀♀; deepened claypan 19 km S of William Creek ; 29°04′55.0″ S, 136°31′59.5″ E; 12 Mar. 2011; M. Schwentner and B.V. Timms leg.; AM P.91331 to P.91334 • 1 ♂, 1 ♀; Stevenson’s Creek ; Horn Expedition leg.; MV J53362 .

Additional material (not examined)

AUSTRALIA – New South Wales • 1 ♂, 1 ♀; E of Lake Lauradale ; 29°51′22″ S, 145°38′49″ E; 29 Mar. 2009; M. Schwentner and B.V. Timms leg.; AM P.80857, P.91344 • 2 ♂♂, 3 ♀♀; E of Lake Lauradale ; 29°51′22″ S, 145°38′49″ E; 18 Jan. 2010; M. Schwentner and B.V. Timms leg.; AM P.91370 to P.91374 • 1 ♂, 3 ♀♀; claypan-like 19 km E of Engonia ; 29°17′06.9″ S, 146°02′23.9″ E; 21 Jan. 2010; M. Schwentner and B.V. Timms leg.; AM P.91348 to P.91351 • 2 ♀♀; Bloodwood Station, Turkey claypan; 29°33′19.8″ S, 144° 50′17.8″ E; 19 Feb. 2010; M. Schwentner, C. Sieves and B.V. Timms leg.; AM P.91359, P.91360 • 1 ♂; Barnato Station , lake next to homestead at 80 km W of Cobar; 31°36′52.4″ S, 144°52′12.6″ E; 29 Mar. 2010; B.V. Timms leg.; raised from sediment; AM P.91284 . – Northern Territory • 1 juv.; Ilpara Claypan Alice Springs ; 23°45′16″ S, 133°47′49″ E; 13 Jan. 2010; J. van der Reijden leg.; AM P.91377 . – Queensland • 3 ♂♂, 2 ♀♀; big claypan 41 km east Wyandra ; 27°22′50.4″ S, 146°18′06.4″ E; 17 Feb. 2010; M. Schwentner, C. Sieves and B.V. Timms leg.; AM P.91361 to P.91365 • 1 ♂, 4 ♀♀; Currawinya National Park , turbid claypan S of North Kaponyee; 28°49′27.4″ S, 144°19′44.5″ E; 24 Feb. 2011; M. Schwentner, S. Richter and B.V. Timms leg.; AM P.91290 to P.91294 • 2 ♀♀; Currawinya National Park, claypan at old Wyara Junction ; 28°47′49.4″ S, 144°17′55.6″ E; 24 Feb. 2011; M. Schwentner, C. Sieves and B.V. Timms leg.; AM P.91317, P.91318 • 1 ♀; Currawinya National Park, Big Darko Claypan ; 28°52′19.1″ S, 144°17′34.5″ E; 25 Feb. 2011; M. Schwentner, C. Sieves and B.V. Timms leg.; AM P.91335 • 1 juv.; black box claypan 58 km from Hungerford Road ; 28°50′23.1″ S, 143°53′46.0″ E; 26 Feb. 2011; M. Schwentner, S. Richter and B.V. Timms leg.; AM P.91310 • 1 ♀; claypan 45 km E of Thargomindah ; 28°05′15.0″ S, 144°15′47.0″ E; 27 Feb. 2011; M. Schwentner and B.V. Timms leg.; AM P.91300 . – South Australia • 1 ♂; vegetated stony dugout 34 km N of Marla ; 27°05′26.8″ S, 133°28′16.2″ E; 10 Mar. 2011; M. Schwentner and B.V. Timms leg.; AM P.91321 • 2 ♀♀; 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.91301, P.91303 • 1 ♀; cane grass swamp 44 km W of Oodnadatta ; 27°20′07.1″ S, 135°07′47.7″ E; 11 Mar. 2011; M. Schwentner and B.V. Timms leg.; AM P.91324 • 2 ♂♂, 1 ♀; Fogatys Claypan 60 km N of Oodnadatta; 27°03′21.4″ S, 135°14′57.2″ E; 11 Mar. 2011; M. Schwentner and B.V. Timms leg.; AM P.91296, P.91297, P.91299 .

Type locality

Brady (1886) noted “Cooper Creek, at Innamincka, Central Australia ” as the locality. As the type material is lost and the exact locality unknown, we designated a neotype. The new type locality is: Australia, Queensland, Currawinya National Park, claypan halfway on northern fence of Bilby enclosure, 28°52′12.8″ S, 144°21′52.1″ E.

Description

Males

CARAPACE ( Fig. 25a–b, d–f). Length 9.6–13.8 mm (NT: 11.0 mm, mean: 11.6 mm), height 5.0– 7.3 mm (NT: 5.6 mm, mean: 6.0 mm). Coloration light brown to dark brown or dark reddish-brown, crowded growth bands lighter, yellowish to whitish (in juveniles carapace lightly colored, sometimes translucent). 16–25 (NT 21, mean: 20) growth lines, 12–18 (NT: 15, mean: 15) widely spaced and 1–9 (NT: 6, mean: 5) crowded.

CARAPACE SHAPE. Dorsal margin straight, dorso-posterior corner distinct or rounded (NT: rounded). Posterior margin rounded, greatly extending posteriorly (giving the whole carapace an oval appearance), supracurvate to strongly supracurvate (b/H: 0.24–0.44, NT: 0.34, mean: 0.32). Mid-section of ventral margin nearly straight, posteriorly widely rounded. Umbo position anterior (Cr/L: 0.17–0.22, NT: 0.22, mean: 0.20).

CARAPACE ORNAMENTATION ( Fig. 25g –h, see also Fig. 26d–e). Larval valve and first few growth bands appear smooth (might be due to abrasion). All other non-crowded growth bands with large reticulations. Reticulations form polygonal mesh across each growth band with each polygon usually being a pentagon, hexagon or heptagon. Under SEM, polygon centers smooth or granular, without secondary reticulations. Reticulations become irregular and transition to broken lines on growth bands of incipient carapace crowding; crowded growth bands very narrow, without obvious ornamentation (under SEM, crowded growth bands and secondary growth phase with inconspicuous, very fine anastomosing liral ornamentation). Concentric ridges raised. Setae very short, thin and inconspicuous, in many individuals none visible; under SEM two irregular rows of setae and corresponding setal pores along all growth lines.

HEAD ( Fig. 25i–j). Condyle short, rounded only weakly protruding; occipital notch wide. Condyle lacking anterobasal hump. Margin between condyle and ocular tubercle straight, rarely slightly concave. Ocular tubercle weakly developed, rarely strongly developed; forming obtuse angle (~110–140°) with rostrum; angle close to 90° when ocular tubercle strongly developed. Anterior margin of rostrum convex. Apex rounded with acute angle (~70°). Ventral margin of rostrum deeply concave with obtuse angle about half-length (sometimes anteriorly close to apex), pointing apex strongly downwards. Naupliar eye very small (rarely not visible), roundish to sub-triangular. Antenna I long, 14–24 lobes (NT: 21; mean: 20), reaching to antenna II flagellomeres III–VIII (NT: XI; mean: VII). Antenna II with 13–17 flagellomeres (NT: 15; mean: 15).

THORAX. 25–28 (NT: 26; mean: 26) segments, 25–27 (NT: 25; mean: 25) thoracopod-bearing and none to two (NT: one) posterior limbless segments not reaching dorsal margin. From about midbody, segments with minute dorsal extensions with few long spines, posteriormost segments usually without spines (juveniles with more extensive dorsal extensions and always with long spines on last segments).

THORACOPOD III (only P.91288; Fig. 25l). 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. 25m –n). 9–20 (NT: 8, mean: 11) spines. First (anterior) spine enlarged. Spines conical. Spines widely and unequally spaced, varying in size, most spines small or tiny, in some individuals and especially juveniles spines larger and more prominent. Dorsal margin anteriorly (to about mid-length) straight, then evenly concavely curved. Right terminal claw more strongly curved than left.

FURCA ( Fig. 25m –n). Proximally with dorsomedial longitudinal row of 8–17 (NT: 11) setae, row ending distally in a single conical spine. Distal part ¼–⅓ of furcal length, with numerous small denticles.

Females

Overall appearance as in males. Carapace ( Fig. 25c) length 9.0–13.0 mm (mean: 10.9 mm), height 4.7–6.9 mm (mean: 5.7 mm); 15–22 (mean: 17) growth lines, 12–17 (mean: 15) widely spaced, and 0–6 (mean: 2) crowded; Cr/L 0.17–0.23 (mean: 0.19) and b/H 0.27–0.40 (mean: 0.32). Ocular tubercle weakly developed, rarely strongly developed; forming obtuse angle (~110–140°) with rostrum (never close to rectangular; Fig. 25k). Anterior margin of rostrum weakly convex (less strongly than in males). Apex of rostrum drawn out into acute tip, protruding weakly to strongly from rostrum, apex forming acute angle ~45–70°. Antenna I with 14–20 small lobes (mean: 18), lobes smaller than in males; reaching to antenna II flagellomeres III–VIII (mean: V). Antenna II with 14–17 flagellomeres (mean: 15). 25–27 (mean: 26) thorax segments, 24–26 (mean: 25) thoracopod-bearing and none to two posterior limbless segment not reaching dorsal margin. Telson with 7–14 (mean: 11) dorsal spines ( Fig. 25o); left and right terminal claws equally curved. Furca with 8–16 setae (mean: 12).

Distribution ( Fig. 26h)

Common and widely distributed in the (semi)arid regions of central and eastern Australia. It lives mostly in very turbid claypans and cane grass swamps and is only rarely found in clearer water bodies.

Remarks

Brady’s (1886) first description of O. lutraria was based only on dried carapaces. Spencer & Hall (1896) described the species in more detail based on newly collected specimens from central Australia (collected a few hundred kilometers W of Brady’s specimens). In the same publication, Spencer & Hall also firstly described O. dictyon . Based on their descriptions and figures, the species were mostly distinguished by fewer thorax segments (‘legs’), smaller overall size, larger and more pronounced spines on the telson, and a lighter (semitranslucent) carapace in O. dictyon . But they did not provide a direct comparison between the two species and mostly compared them to O. packardi . In our morphometric analyses, both species (including the type material of O. dictyon and the specimens of O. lutraria studied by Spencer & Hall) clearly overlapped ( Fig. 5) and the types of O. dictyon were classified as O. lutraria with a probability score of 1. Moreover, juvenile specimens of O. lutraria studied by us clearly showed the morphological features otherwise associated with O. dictyon . Taken together, O. dictyon probably represents subadults or late juveniles of O. lutraria . As O. lutraria was described first, O. dictyon is a junior synonym of O. lutraria . This was already suggested by Dakin (1914); however, without providing any explanation and subsequent authors did not follow his suggestion.

Assigning O. lutraria to one of the species genetically differentiated by Schwentner et al. (2015a) was not as straightforward as anticipated. The species genetically differentiated as O. sp. C has been previously referred to as O. lutraria (e.g., Richter & Timms 2005). However, the original description of O. lutraria is very brief and based solely on a single dried-out “somewhat shrunk and distorted” carapace ( Brady 1886: 85). When we included the original drawing of O. lutraria by Brady (1886) in our geometric morphometric analyses, it was placed somewhat intermediate between O. lutraria , O. matuwa sp. nov., O. henryae sp. nov. and O. christiani sp. nov. ( Fig. 5), with the highest similarity to O. lutraria (probabilities of 44.2%, 7.2%, 33.1% and 15.0%, respectively; Supp. file 1_4.2). But even for O. lutraria , the specimen represented an outlier shape. The differences between Brady’s drawing and all other specimens of O. lutraria are a convex ventral margin and a less steeply inclined ventroposterior margin in the drawing. Brady also described the carapace to be compressed behind the middle when seen from dorsal. Such a strong compression was observed neither in specimens of O. lutraria nor in any other studied species of Ozestheria . Probably the carapace distorted when drying out, leading to this posterior compression. There are two strong arguments in favor of O. sp. C representing O. lutraria . Ozestheria sp. C has the largest carapace of all the species studied herein and the size of Brady’s specimen (H: ~ 6.4 mm, L: 11.1 mm) falls well within its size range and is even close to its mean values, whereas the carapaces of O. christiani sp. nov. and O. paralutraria sp. nov. are smaller than Brady’s specimen. Furthermore, Ozestheria sp. C has been collected from a large number of localities all around (west, north and east) the former type locality at Innamincka in northern South Australia. Ozestheria christiani is known from a single locality in southern South Australia only, ~ 500 km from the former type locality of O. lutraria , and O. sp. X11 from an even more distant locality in northwestern Western Australia.

Genetically, O. lutraria is most similar to O. paralutraria sp. nov. with uncorrected p -distances in COI of only 4.2–4.9% (Supp. file 4).

Ozestheria lutraria shows remarkable ontogenetic changes between late juvenile (or subadult) stages and adults. This affected not only expected ontogenetic changes such as an increase in the number of thorax and antennal segments or the number of furcal setae, but also changes not necessarily associated with late ontogeny: with increasing age, spines on the dorsal extension on the last thorax segments are reduced, the spines on the telson decrease in size and become more conical ( Fig. 25m –o) (juveniles with longer and more aciculate spines; Fig. 26f–g) and the distal portion of the furca decreases in size relative to the basal portion. A few adults still had spines on the dorsal extension or several larger spines on the telson and it is possible that these characters would have further changes with subsequent molts.

To clarify the taxonomic status of O. lutraria , it was deemed necessary to designate a neotype, particularly in the light of the many newly described species, some of which are morphologically similar to O. lutraria , and the newly established synonymy with O. dictyon . There is no evidence that the driedup carapaces collected by Brady are preserved in any collection; requests to relevant collections yielded no such material and also Richter & Timms (2005) suggested that the original material was lost. No material from the type locality was available and a specimen from a comparable locality was selected. The neotype was selected to match both the original description of Brady as well as the redescription by Spencer & Hall as closely as possible.