Moinidae Goulden 1968
Creators: name: Alonso, Miguel
name: Neretina, Anna N.
name: Sanoamuang, La-Orsri
name: Saengphan, Nukul
name: Kotov, Alexey A.
Publisher: name: Zenodo
Year: 2019
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Branchiopoda
Diplostraca
Moinidae

description: Family Moinidae Goulden, 1968
Genus Moina Baird, 1850
Moina siamensis sp. nov.
(Figs. 1–10)
Etymology. This new species is named after Siam, the former name of Thailand, the country from which it was collected.
Type locality. A roadside temporary pond in Nong Yasai district, Suphan Buri province, Thailand, (14°45'55.30"N, 99°46'05.34"E). From this locality, 60 parthenogenetic females, 60 males and 40 ephippial females were collected by Nukul Saengphan on 26 April, 2007. At the time of sampling, physicochemical parameters of water were: temperature 30.7°C, pH 7.3, conductivity 98 µs cm -1, and dissolved oxygen 5.07 mg L -1.
Holotype. A parthenogenetic female in 95% ethanol deposited at the collection of Zoological Museum of Moscow State University, MGU Ml 164. Holotype label: “ Moina siamensis sp. nov., 1 parth. ♀ from a roadside pond, Nong Yasai district, Suphan Buri province, Thailand, HOLOTYPE ”.
Allotype. Adult male in 95% ethanol deposited at the collection of Zoological Museum of Moscow State University, MGU Ml 165. Allotype label: “ Moina siamensis sp. nov., 1 ³ from a roadside pond, Nong Yasai district, Suphan Buri province, Thailand, ALLOTYPE ”.
Paratypes from a roadside pond, Nong Yasai district, Suphan Buri province, Thailand, preserved in 95% ethanol: 10 undissected parthenogenetic females (MGU Ml 166); 5 undissected males (MGU Ml 167); 5 undissected ephippial females (MGU Ml 168); 10 undissected parthenogenetic females (AAK 2018-060); 5 undissected males (AAK 2018-061).
Other material studied. Twenty parthenogenetic females from temporary pools in Muang district, Suphan Buri province, 14°29'43.44"N, 99°58'40.44"E. 20 parthenogenetic females, 20 males and 20 ephippial females from Don Chedi district, Suphan Buri province, 14°38'39.48"N, 99°52'11.64"E. 30 parthenogenetic females, 10 males and 10 ephippial females, Sri Prachan district, Suphan Buri province, 14°36'33.12"N, 100°57'21.6"E, coll. 26 April 2007, Nukul Saengphan (see other localities in Table 1).
Description. Parthenogenetic female (Figs. 1, 5 A–B, E–H). General. Body ovoid in lateral view, moderately low for genus (body height/length = about 0.64), maximum height in middle portion (Figs. 1A, 5A). Dorsum of valve significantly elevated behind head, almost straight in posterior portion. Shallow dorsolateral depression separates head from rest of body. Posterodorsal angle prominent, acute, posteroventral angle broadly rounded. Ventral margin moderately convex. Anterodorsal angle prominent, rounded (Figs. 1A, 5A). Very fine sculpture on valves, forming cells elongated in dorsoventral direction (Figs. 5 A–B). No integumental hairs on head and valves (Figs. 1A, 5 A–B, 5G–H). Body laterally compressed in anterior view. Body elongated, subovoid in dorsal and ventral view.
Head relatively large, with shallow supra-ocular depression and massive compound eye (Figs. 1A, 5 A–B, G). Ocellus absent. Head pores absent.
Labrum with fleshy main body, its ventral margin slightly concave, labral plate densely setulated (Fig. 1B).
Valves large, broadly ovoid (Figs. 1A, C, 5 A–B). Anterior portion of ventral margin provided with moderately long setae covered by tiny setulae (Fig. 1C); in posterior portion of ventral margin, long setae replaced by fine setulae. Anteriormost setulae organized in 2 or 3 groups, but then setulae gradually decreasing in size towards dorsal margin. Setulated hooks located in the dorsal most portion of posterior margin in both valves (Fig. 1C).
Thorax relatively long (Fig. 1A).
Abdomen short (Fig. 1A).
Postabdomen elongated, conically narrowing distally (Figs. 1A, D, 5 E–F); ventral margin almost straight, with rows of minute setulae (Fig. 1D). Preanal margin long, convex, gradually passing to anal margin. Preanal and anal portions are covered by rows of minute setulae (Fig. 1D). Postanal portion conical, both distal margin and dorsodistal angles not expressed. Laterally postanal portion of postabdomen bearing a row of 8–10 large, triangular, plumose teeth (Figs. 1D, 5 E–F). Anteriormost tooth bidentate, with branches unequal in length (Figs. 1D, 5 E–F).
Postabdominal setae slightly longer than postabdomen, its distal segment 2× longer than proximal segment (Figs. 1A, D).
Postabdominal claw large, slightly curved, with pointed tip (Figs. 1A, D, 5 E–F); its outer lateral side covered by row of denticles decreasing in size towards tip. Prominent group of larger denticles near base of claw. Ventral margin of claw with several denticles in its basal portion.
Antenna I thin (length approximately equal to 6 diameters of antennular body base), long, slightly curved (Figs. 1 E–F, 5G–H); surface covered by numerous fine long setae and rows of minute denticles. Antennular sensory seta slender, arising almost at middle of antennular body; 9 short aesthetascs almost subequal in size (Figs. 1 E–F, 5G–H).
Antenna II large and long; coxal part with 3 setulated sensory setae subequal in length (Figs. 1 G–H). Basal segment robust, with short distal spine on outer surface between antennal branches and long seta on inner surface; this segment covered by numerous transverse rows of fine denticles and long setae (Figs. 1 G–H). Antennal branches elongated. Exopod 4-segmented, subequal in size to 3-segmented endopod. All branch segments cylindrical, with rows of small denticles and setae. Antennal formula: setae 0-0-1-3/1-1-3, spines 0-1-0-1/0-0-1. Lateral and apical swimming setae of both antennal branches covered by long, fine setulae. Spine on second exopod segment short, comparable in length with both apical exopod and endopod spines (Figs. 1 G–H).
Thoracic limbs: 5 pairs (Figs. 2 A–H).
Limb I (Fig. 2A) with elongated, narrow corm; inner distal lobe (or endite 5 sensu Kotov (2013)), with single anterior seta, bearing short setulae, and 2 soft setae (Fig. 2A: 1, a–b). Armature of posterior soft setae similar in all limbs: both segments provided with fine, long setulae. Endite 4 with single, relatively short anterior seta, and single posterior seta (Fig. 2A: 2, c). Endite 3 with 2 posterior setae, without anterior setae (Fig. 2A: d–e). Endite 2 with 3 posterior setae (Fig. 2A: f–h). Two ejector hooks of remarkably different size. No maxillar process (or endite 1 sensu Kotov (2013)) on limb base.
Limb II (Figs. 2 B–C) large. Limb distal portion (exopodite) as large lobe bearing large soft seta and small lateral seta; 3 endites bearing 4 soft posterior setae, and 2 small setae of unclear homology near gnathobase (Fig. 2B: a–d and other unnumbered setae). Gnathobase with 2 clear rows of setae (Figs 2 B–C): 4 anterior setae, single long seta (1) near beating seta, and 3 setae in basal corner of gnathobase (2–4), increasing in size distally, and 11 posterior setae (a–k) of gnathobase “filter plate”.
Limb III (Figs. 2 D–E) with large ovoid epipodite, and ovoid flat exopodite bearing 4 distal and 2 lateral setae remarkably different in length. Inner distal portion of limb with 3 endites (Fig. 2E). Endite 3 with single posterior seta and single anterior seta (Fig. 2E: 1, a); endite 2 with single anterior and 2 posterior setae (Fig. 2E: 2, b–c); endite 1 with single anterior and 4 posterior setae (Fig. 2E: 3, d–g). Remainder of limb represented by single lobe, bearing numerous soft setae, covered by short setulae.
Limb IV (Figs. 2 F–G) with large ovoid epipodite, and ovoid flat exopodite, bearing 4 distal and 2 lateral setae remarkably different in length (Fig. 2F). Inner distal portion of limb with 2 endites: endite 2 with anterior seta and posterior seta (Fig. 2G: 1?, a); endite 1 with anterior seta and 2 posterior setae (Fig. 2G: 2?, b–c). Other parts of limb are represented by single lobe, bearing numerous soft setae, covered by short setulae (Figs. 2 F–G).
Limb V (Fig. 2H) with large ovoid epipodite and exopodite bearing large distal and small apical setae. Inner limb portion as flat, ovoid lobe, with setulated inner margin, and 2 setae unequal in size (Fig. 2H: 1–2).
Ephippial female (Figs. 3 A–D, 4A, 5C–D, 6A–L, 7A–J, 8A–E). Body shape and appendages of ephippial female appearing similar to those of parthenogenetic female but with dorsal portion transformed into ephippium (for resting egg), laterally expanded (e.g. Figs. 3 A–D). Dorsal part of valves with reinforced dorsal chitinous plate (Figs. 3 A–C, 4A, 5C–D, 6A–B, 8A–B), expanded to center in dorsal view. Ephippium yellow-brownish (Figs. 4 A– B). Macrosculpture of ephippium as polygonal cells at margins and prominent longitudinal lines in central portion (Figs. 3 A–D, 4A–B, 5C–D, 6H and others), these features well recognizable both under light and scanning electron microscopy. Microsculpture as tiny rounded hillocks, visible only under scanning electron microscope (Figs. 6 B–J, 8B–E). Ephippium containing single resting egg.
Male (Figs. 3 E–J, 9A–E, 10A–M). General. In lateral view body ovoid, more elongated compared to female (body height/length about 0.55) (Figs. 3E, 9 A–B). Dorsal margin of valves slightly elevated above head, posteroventral angle distinct (Figs. 3E, 9 A–B).
Head longer than in female; labrum somewhat thinner than that of females, with large, setulated distal labral plate (Figs. 3E, 9 A–B, 10B). Head pores absent. Compound eye large. Ocellus absent.
Valve ovoid, more elongated than that in female, with short setae, decreasing in size posteriorly, along ventral margin (Figs. 3E, 9 A–B, 3F). Setulated spine on inner face of valve near posteroventral angle. Posterior portion of ventral margin with successive series of fine, exactly marginal setulae. Anterior portion of ventral margin with row of setae, increasing in size to central part with 4 or 5 setae more than 6× longer than those of anterior part. In contrast to parthenogenetic and gamogenetic females, outer surface of valves in males covered by fine relatively long hairs (Figs. 3F, 9C, 10 C–G).
Thorax (Fig. 3E) relatively long.
Abdomen (Fig. 3E) short.
Postabdomen generally as in female, with large bidentate tooth distally (distal branch always significantly large than basal branch), and row of 7–9 large, triangular plumose teeth (Figs. 3E, G, 10H). Gonopore opening in lateral surface of postabdomen.
Postabdominal setae (Fig. 3E) almost 2× longer than postabdomen. Its distal segment significantly longer than proximal one.
Antenna I very long and regularly curved, covered by tiny hairs and rows of small denticles (Figs. 3H, 9 C–E, 10I–J). Antennular sensory seta long, arising from first quarter of antennular body. Male seta more robust, located near sensory seta. Apical tip of antennular body separated into 2 parts: first with 9 short aesthetascs, second with 4 hooks.
Thoracic limb I essentially similar to that in parthenogenetic female, but with large, curved copulatory hook with setulated margin and pointed apex (Figs. 3 I–J, 10L–M).
Size. Adult parthenogenetic females 0.50–0.99 mm in length; ephippial females up to 0.92 mm in length; adult males 0.50–0.89 mm in length. Juvenile females to 0.5 mm in length. Holotype 0.99 mm in length; allotype 0.89 mm in length.
Variability. No significant variability was found in individuals between localities.
Differential diagnosis. In tropical Asia, Moina siamensis sp. nov. is close to M. weismanni Ishikawa, 1896, resulting in possible confusion. Morphology of parthenogenetic females and males of both species is nearly identical. Based on current knowledge of moinid morphology, we suggest that the ephippium should be used as the primary and most reliable diagnostic feature for discrimination between sibling species. The mature ephippium of M. siamensis sp. nov. is characterized by prominent longitudinal lines in its central region, whereas the ephippium of M. weismanni (Figs. 12 A–C) is strongly tuberous, with distinct borders between tubercles. These features are recognizable both under light and scanning electron microscopes. However, we can only identify populations that contain mature gamogenetic females. Primary differences between Moina siamensis sp. nov. and other tropical moinids are discussed below.
Distribution and ecology. Until now, Moina siamensis sp. nov. was known only from temporary water bodies in Thailand (Table 1, Fig. 11). It occurs nationwide, including northern, central, northeastern, eastern, and southern regions. This species inhabits shallow, roadside ponds, and pools (especially rice fields) with developed vegetation buffers, industrial wastewater treatment ponds, and animal farms. Moina siamensis sp. nov. was collected during the wet season (May and October). Some physicochemical parameters of the water were: temperature 26.5–34.0°C, conductivity 48.0–142.0 µScm -1, pH 6.1–8.5, and dissolved oxygen 1.75–7.82 mg L -1. Moina siamensis sp. nov. usually co-exists with M. micrura, but the latter species occurs in both temporary and permanent ponds (Sanoamuang 1998).
Economical value for aquaculture. The sizes of adults and juveniles of M. siamensis sp. nov. range from 0.25–0.50 and 0.50–0.99 mm, which are suitable to feed juvenile freshwater fish or shrimps. Recent culture experiments demonstrated that M. siamensis sp. nov. contains 61.04% protein and 7.96% lipids. They can be cultured commercially in Thailand. Adults and dried eggs of this new species are presently sold in local markets.
description: Published as part of Alonso, Miguel, Neretina, Anna N., Sanoamuang, La-Orsri, Saengphan, Nukul & Kotov, Alexey A., 2019, A new species of Moina Baird, 1850 (Cladocera: Moinidae) from Thailand, pp. 199-218 in Zootaxa 4554 (1) on pages 200-209, DOI: 10.11646/zootaxa.4554.1.6, http://zenodo.org/record/2623492