Coronatella (Ephemeralona) vermiculata ( Smirnov & Timms, 1983 ), 2025

Sinev, Artem Y., 2025, Cladocera of subgenus Coronatella (Ephemeralona) Sinev, 2020 (Anomopoda: Chydoridae) from South Africa and Australia, Zootaxa 5659 (2), pp. 257-272 : 262-269

publication ID	https://doi.org/10.11646/zootaxa.5659.2.7
publication LSID	lsid:zoobank.org:pub:99BAEEC0-9E90-4ABE-84ED-BEF9D951AD6E
persistent identifier	https://treatment.plazi.org/id/0E6687ED-FFB4-FF8B-FF71-FEB2123FFE68
treatment provided by	Plazi
scientific name	Coronatella (Ephemeralona) vermiculata ( Smirnov & Timms, 1983 )
status	comb. nov.

Treatment

Coronatella (Ephemeralona) vermiculata ( Smirnov & Timms, 1983) comb. nov.

( Fig. 2–6 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 6 )

Smirnov & Timms 1983: 41 ( Alona davidi vermiculata ).

Type material and type locality were not designated, type series includes three slides deposited in Australian Museum, Sydney, in Zooloogical museum of M. V. Lomosov Moscow State University , and in Zoological Museum of Zoological Institute of Russian Academy of Sciences, Saint-Petersburg.All these slides are from the same locality, labeled as “Lake near Island Lake, via Cooma, New South Wales, Australia ”. So the type locality and lectotype are designated here .

Type locality. Lake near Island Lake, via Cooma, New South Wales, Australia, 12.05.1975, coll. B. V. Timms. Approximated coordinates of locality: 36°14' S, 148°56' E GoogleMaps .

Lectotype. Parthenogenetic female from type locality, deposited in Australian Museum, Sydney, access number P.27687.001. Paralectotypes. Parthenogenetic female from type locality on slide 2982 (type series) from N.N. Smirnov’s slide collection deposited in Zoological Museum of M. V. Lomonosov State University, Moscow, no separate access number; parthenogenetic female from type locality on slide 2982 (type series) from N.N. Smirnov’s slide collection deposited in Zoological Museum of Zoological Institute of Russian Academy of Sciences , Saint-Petersburg, access number 54875 .

Other material studied. 8 adult parthenogenetic females from unnamed lake via Berridale , north-west of Cootralantra Lake (lake coordinates 36˚15’47.40” S, 148˚53’25.95” E) New South Wales, Australia, 12.05.1975, NNS-2000-030, from N.N. Smirnov’s sample collection kept at A.N. Severtsov Institute of Ecology and Evolution of Russian Academy of Sciences, Moscow, labeled as Alona davidi vermiculata by N.N.Smirnov; 3 parthenogenetic females , 1 male from roadside ditch near Beeac road near Lake Weering salt lake (lake coordinates 38˚04’51.24”S, 143˚40’3013”E), Victoria, Australia, 13.12.1986, coll. D.G. Frey, DGF- 8132 in the collection of Prof. D.G. Frey at the National Museum of Natural History, Smithsonian Institutes, Washington D.C., USA, general access number 403774 .

Description. Parthenogenetic female. General. In lateral view, body ovoid, compressed laterally, moderately high ( Fig. 2A, K View FIGURE 2 3A–D View FIGURE 3 ). Maximum height at before the middle of body. Height-length ratio 0.55–0.6 in adults. Dorsal margin unevenly convex, with almost straight posterior portion, postero-dorsal angle weakly defined, and postero-ventral angles broadly rounded. Posterior margin weakly convex, ventral margin almost straight, antero-ventral angle rounded. No gap between ventral margins of valves ( Fig. 3C View FIGURE 3 ). Ventral margin ( Fig. 2B View FIGURE 2 ) with about 55 setae. About 12 anterior setae longer than others, next 10 setae short, posterior setae of moderate length. Armament of postero-ventral angle ( Fig. 2C–F, L View FIGURE 2 , 3E View FIGURE 3 ) very variable. Two-six posteriormost ventral setae thicker than previous, without plumose setulation, in some specimens one–three last setae transformed into triangular spines. Setae followed with 20–40 short setulae not organized into groups. A row of about 80 very short setulae on inner side of carapace parallel to ventral margin of valves. Carapace covered by thick, densely spaced longitudinal lines, the distance between lines is much smaller than the width of the lines ( Fig. 3E–F View FIGURE 3 ).

Head ( Fig. 3G–H View FIGURE 3 ) relatively small, triangular-round in lateral view, rostrum short, truncated, pointing downward. Eye larger than ocellus. Distance from the tip of rostrum to the ocellus greater than that between the ocellus and the eye.

Headshield ( Fig. 3H View FIGURE 3 , 4A View FIGURE 4 ) with maximum width behind mandibular articulation, with same sculpturing as on valves. Rostrum short, with truncated apex. Posterior margin of headshield broadly rounded, sometimes slightly wavy. Three narrowly connected major head pores ( Fig. 2G View FIGURE 2 , 3D View FIGURE 3 ), middle pore slightly smaller than others, located at the middle between others. PP about 0.5–0.6 IP in adults. Lateral head pores slightly elongated, located at about 0.7 IP distance from midline, at the level of the anterior major head pore.

Labrum relatively large ( Fig. 2H–I View FIGURE 2 ). Labral keel wide (height/width ratio about 1.25), with a broadly rounded apex. Anterior margin of keel convex, posterior margin without clusters of setulae.

Thorax two times longer than abdomen. Dorsal surface of abdominal segments ( Fig. 4D View FIGURE 4 ) not saddle-shaped. No abdominal projections.

Postabdomen ( Fig. 4D View FIGURE 4 , 5A–B, D View FIGURE 5 ) of moderate length and width, with almost parallel margins in anal portion, narrowing in postanal portion, with broadly rounded distal angle. Length about 2.5–2.7 height. Ventral margin straight. Basis of claws bordered from distal margin by clear incision. Distal marginal convex. Dorsal margin with distal part 1.8–2 times longer than preanal one; postanal portion slightly longer than anal portion. Postanal portion weakly convex to almost straight; anal portion weakly concave. Preanal angle well defined, postanal angle weakly defined to not defined.

Postanal margin ( Fig. 4E View FIGURE 4 ) with 7–8 clusters of 2–4 elemental marginal denticles, decreasing in size basally. In population from NNS denticles shorter, and 1–2 distal groups are merged into composite denticle. In population from DGF denticles longer and more numerous, no groups are merged. Length of longest elements less than width of postabdominal claw base. Anal margin with 3–4 groups of setulae. Eight–ten groups of lateral setulae in the main row; postanal groups wide, closely spaced, consisting of 10–15 setulae each, with distalmost setula being longest and thicker than others. Length of distalmost setulae equal or slightly greater than width of postabdominal claw base. Postabdominal claw ( Fig. 4F View FIGURE 4 ) weakly curved, of moderate length, as long as preanal portion of postabdomen. Basal spine long and thin, about 0.3 of length of claw, a cluster of 3–6 long setulae located near its base.

Antennule ( Fig. 2J View FIGURE 2 ) narrow elongated, almost reaching tip of rostrum, with 3 clusters of long setulae at anterior face. Length/width ratio about 2.5. Antennular sensory seta slender, 2.5 times shorter than antennule, arising at about 2/3 distance from the base. Nine aesthetascs, three longest about 2/3 length of antennule.

Antenna short ( Fig. 3G View FIGURE 3 , 4C View FIGURE 4 , 5C View FIGURE 5 ). Antennal formula, setae 0-0-3/1-1-3, spines 1-0-1/0-0-1. Two coxal setae. Basipodite robust, branches short and stout. Basal segments of both branches almost two times longer than middle and apical segments. Seta arising from basal segment of endopodite thin, longer than endopodite. Seta arising from middle segment of endopodite as long as shortest apical setae. Both apical segments with one shorter and two longer setae of similar thickness. Spine on basal segment of exopodite slightly shorter than middle segment. Spines from apical segments longer than respective apical segments.

Thoracic limbs: five pairs.

Limb I ( Fig. 6A–B View FIGURE 6 ) of moderate size. Epipodite oval, with process as long as epipodite. Accessory seta long and thick, about 2/3 length of ODL seta. ODL seta with minute setulation. IDL with 3 setae; seta 1 very small; seta 3 as long as ODL seta; seta 2 slightly shorter than seta 3. Setae 2 and 3 armed with thin spinules. Endite 3 with four setae, seta 1 shorter and thinner than others (a–c). Endite 2 with seta d as long as setae of endite 3; seta e very long, longer than limb itself; seta f about 3/5 length of seta e. Endite 1 with 2 distally setulated 2-segmented setae (g–h) and a long flat seta (i) as long as setae a–d. No naked inner setae (2–3) and sensillae on endites 1 and 2. Six rows of thin long setulae on ventral face of limb. Two ejector hooks, one longer than other.

Limb II ( Fig. 6C–D View FIGURE 6 ). Exopodite elongated, with seta shorter than exopodite. Eight scraping spines armed with thin setulae, decreasing in length basally, setae 1–5 long, setae 6–8 much shorter, with more robust spinulae. Small seta located near the base of scraper 1. Distal armature of gnathobase with 4 elements. Filter plate with 7 setae, two posteriormost setae considerably shorter than others.

Limb III ( Fig. 6E–F View FIGURE 6 ). Epipodite oval without process. Exopodite rounded, with 6 setae. Seta 3 extremely long, two times longer than longest setae of exopodites IV–V; seta 5 and 6 of about 1/3 and 1/5 length of seta 3, respectively, other setae very short. Setae 1–4 plumose, seta 5 armed with two types of setulae in distal portion, seta 6 armed with short setulae in dorsal portion. Distal endite with three setae; two distalmost setae (1–2) slender, sharp, of similar length, with long denticles in distal part; basalmost seta 1.5 times shorter, flattened and setulated in distal portion. Basal endite with 4 outer setae (a–d) increasing in length basally. Gnathobase not clearly separated from basal endite. Inner portion of limb typical for morphology of the genus not studied in detail. Filter plate with seven setae.

Limb IV ( Fig. 6G–H View FIGURE 6 ). Preepipodite setulated; epipodite oval, with process as long as epipodite. Exopodite rounded, with 6 setae; seta 3 longest; seta 1–2 slightly shorter than seta seta 3; setae 4, 5 and 6 of about 1/3, 2/3 and 1/2 length of seta 3, respectively. Setae 1–4 flattened, plumose; setae 5 and 6 slender, with short setulae in distal portion. Inner lobe of limb IV with 4 setae and small sensillum ( Fig. 6H View FIGURE 6 ). Distalmost seta (1) slender, sharp, flaming-torch seta (2–4) of similar size, with elongated basal portion, armed 7–9 thin setulae each. Three soft setae (a–c) increasing in size basally. Gnathobase with 2-segmented seta, and a small mound distally. Filter plate with 5 setae.

Limb V ( Fig. 4I View FIGURE 4 ). Preepipodite setulated, epipodite oval, with process as long as epipodite. Exopodite elongated oval, not divided into two lobes, with four plumose setae with thick basal portion, decreasing in size basally; seta 4 three times shorter than seta 1. Inner lobe of limb rounded, with setulated inner margin. At inner face, two setae, one 2 times longer than another. Filter plate not found.

Ephippial female unknown.

Male. Adult male ( Fig. 2M View FIGURE 2 ) with low oval body, lower than in female, height/length ratio 0.57. Dorsal margin only weakly curved. Ocellus and eye smaller than in female. Labrum slightly broader that in female ( Fig. 2O View FIGURE 2 ), posteroventral angle of valves ( Fig. 2N View FIGURE 2 ) with same armament as in female.

Postabdomen ( Fig. 5E View FIGURE 5 ) moderately wide, with almost parallel margins in anal portion, slightly narrowing distally in postanal portion, with broadly rounded dorso-distal angle. Ventro-distal angle well defined, obtuse. Sperm duct openings located ventrally at the end of postabdomen. Postanal angle not defined, preanal angle well-defined, prominent. Distal part of postabdomen two times longer than preanal, postanal portion slightly longer than anal. Clusters of short setulae in place of marginal denticles, lateral groups of setulae similar to these in the female. Postabdominal claw two times shorter than in female, with blunt tip with several setulae. Basal spine long, about 0.3 length of claw, a cluster of four long setulae located near its base.

Antennule ( Fig. 2P View FIGURE 2 ) thicker than in female, with 2 lateral aesthetascs, I was unable to count terminal aesthetascs (all other species of Coronatella have 10 terminal aesthetascs). Lateral aesthetascs and longest terminal aesthetasc only slightly shorter than antennule. Male seta arising at 2/3 length from the base, about half of antennule length.

Thoracic limb I ( Fig. 6J–K View FIGURE 6 ) with short U-shaped copulatory hook 1.5 times shorter than limb itself. Copulatory brush present, copulatory brush seta short. Ventral face of limb below them with double row of short thick setulae. Inner distal lobe without seta 1; setae 2 and 3 much shorter and thinner than in female, of similar length; male seta curved, slightly shorter than setae 2–3. Endite 3 with long slender seta 1, longer than setae a–c.

Size. In adult parthenogenetic female length 0.46–0.54 mm, height 0.28–0.32 mm. In single studied adult male, length 0.37 mm, height 0.21 mm.

Differential diagnosis: Coronatella (Ephemeralona) vermiculata shares main diagnostic features of subgenus Ephemeralona (see Sinev 2020b) including sculpturing of the valves as densely spaced lines, seta arising from basal segment of antennal endopodite much longer than endopodite, and setae 2–3 of IDL armed with uniform thin setulae. The unique characteristics of the species are truncated rostrum and spine-like setae on posteroventral angle of valves. C. (E.) vermiculata have the most densely spaced longitudinal lines on valves among the subgenus and fully sculptured head shield, this character clearly separates it from C. (E.) anemae , C. (E.) salina , C. (E). flossneri, C. (E.) irinae and C. (E.) montana , which have less densely spaced lines on valves (distance between lines much greater than line width) and head shield without distinctive sculpture (see Korovchinsky et al. 2021, Hudec 2010, Sinev et al. 2009, Sinev 2020). C. (E.) vermiculata also clearly differs from C. (E.) elegans , C. (E.) anemae , and C. (E.) montana (see Sinev 2020b, Korovchinsky et al. 2021, Hudec 2010) in short seta 4 of exopodite III (in these species it has a similar length with seta 5), and from C. (E.) orellanai (see Alonso 1996) in single row of lateral groups of setulae on postabdomen (two in the latter species).

Males of C. (E.) vermiculata clearly differ from those of C. (E.) anemae , C.(E). flossneri, C. (E.) irinae and C. (E.) striolata in wide postabdomens with parallel margins in anal portion (in all these species postbdomen is narrowing in anal portion and have narrow postanal portion).

Distribution: Australia, New South Wales and Victoria.