Moina wierzejskii Richard 1895
Creators: name: Neretina, Anna N.
name: Kirdyasheva, Anna G.
name: Kotov, Alexey A.
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Branchiopoda
Diplostraca
Moinidae
Moina
Moina wierzejskii

description: Moina wierzejskii Richard, 1895
(Figs. 1–5)
Moina wierzejskii Richard 1895: p. 195 –199, figs. 9–13; Goulden 1968: p. 42–48, figs. 17a–e (reproduced from Richard 1895), 18a–e, 19a–d (original); Smirnov 1976: p. 206–208, figs. 187 (from Goulden 1968), fig. 188 (from Goulden 1968, with an exception of male antenna I).
? Moina wierzejskii in Olivier 1962: p. 217, pl. VIX, figs. 1–3 (reproduced from Richard 1895).
? Moina wierzejskii in Smirnov 1976: fig. 188 (antenna I of male from Birabén 1917).
Etymology. Richard named this species in honor of Dr. A. Wierzejski, a Polish scientist who discovered this species (Wierzejski 1892), but wrongly identified it as M. brachiata (Jurine, 1820) (Richard 1895).
Type locality. “Environs de Port-au Prince” (surroundings of Port-au Prince), Haiti, Great Antilles Archipelago in the Caribbean Sea, North America (Richard 1895).
Type material. Author’s syntypes at the Smithsonian National Museum of Natural History: 5 parthenogenetic females, 5 ephippial females and 5 males from “Mare T. Vienp. et Briqueterie. Port au Prince”, Haiti, coll. 01.05.1885, DGF 0800; 3 parthenogenetic females, 2 ephippial females and 1 male from “Carrefour. Port-auPrince ”, Haiti, DGF 0836; 10 parthenogenetic females, 6 ephippial females and 3 males from “ Mare Coucher Blain. Port au Prince ”, Haiti, coll. 01.05.1896, DGF 0751.
Diagnosis. Species of large size for the genus (length of adult parthenogenetic female up to 1.15 mm). Parthenogenetic female with body shape typical of the genus. Surface of head and valves covered with fine hairs. Head without rostrum and dorsal head pore; ocellus absent. On the inner side of the valve, setulae after ventralmost setae not grouped. Preanal and anal margins of postabdomen covered by rows of short setulae. Basal pecten on the dorsal edge of postabdominal claw prominent. Antenna I relatively thick. Antenna II and thoracic limbs as for the genus. Ephippium brownish, containing two resting eggs. Its dorsal part with microsculpture represented by small polygons. In lateral view, macrosculpture of ephippium is represented by polygonal protruding knobs with wavy edges. Male with elongated body. Anteroventral portion of male valve with longer hairs than in female. Gonopore opening on the lateral surface of the postabdomen at some distance from base of postabdominal claw. Antenna I long, terminally with four thick bisegmented hooks of similar size. Thoracic limb I without exopodite. Stiff seta 1 of male limb I thick, with blunt tip.
Redescription. Parthenogenetic female (Figs. 1–2, 4 A–C). General. Body ovoid in lateral view, shape typical of the genus (body height/length ratio is about 0.50 – 0.80 for adults, varies significantly due to the extension of brood chamber’s development), maximum height in the middle (Figs. 1A – B). Dorsal margin of valve elevated above head level (Fig. 1A – B). Posterodorsal angle of carapace expressed, usually acute (Figs. 1A – B, G). Posteroventral angle broadly rounded. Ventral margin of valve rounded, anterodorsal angle rounded (Figs. 1A – B, G). Sculpture of valves fine, represented by cells elongated in dorsoventral direction (not shown on the figures). Fine hairs present on head and valve surface (Figs. 1D, H). In dorsal (Fig. 1C) and ventral view, body subovoid, laterally compressed in anterior view.
Head typical of the genus, with a shallow supra-ocular depression (Figs. 1A – B). Compound eye large, ocellus absent. Dorsal head pores absent (Figs. 1C).
Labrum with a fleshy main body, its ventral margin almost straight, labral plate covered terminally by long setulae (Figs. 1 E–F).
Valve large, ovoid (Figs. 1 A–B, G). Anterior portion of ventral margin with relatively long setae, covered by minute setulae (Figs. 1 H–I, 4A). Ventral margin and posteroventral valve portion with a row of fine ungrouped denticles after the posteriormost seta (Figs. 1 J–K, 4B–C). Setulated curved hooks in the dorsalmost portion at valve posterior margin (Figs. 1A, L).
Thorax relatively long, abdomen short (Figs. 1 A–B).
Postabdomen elongated, conically narrowing distally (Figs. 1 M–N). Its shape and armature typical of the genus. Ventral margin of postabdomen straight, with transverse rows of fine setulae (Fig. 1M). Preanal portion long, gradually passing to anal margin. Preanal and anal portions covered by rows of fine short setulae (Fig. 1M). Postanal portion conical, both distal margin and dorsodistal angles not expressed (Figs. 1 M–N). Laterally postanal portion of postabdomen bearing a row of 9–10 large, triangular, plumose teeth. Anteriormost tooth bidentate, with branches unequal in length (Figs. 1 M–N).
Postabdominal setae long according to original description (Richard 1895: p. 196, fig. 9), slightly shorter than postabdomen and covered by fine setulae throughout. Unfortunately, all specimens in our materials lost distal segments of postabdominal setae, probably, due to an unsuccessful fixation. Fine setulae on both distal and proximal segments of postabdominal setae were later illustrated by Goulden (1968: p. 42, fig. 17b), but not mentioned by Smirnov (1976). In our material we did not find setulae on proximal segments of postabdominal setae (and this observation corresponds well with observations on other species of the Moinidae).
Postabdominal claw large, slightly curved, with pointed tip (Figs. 1 M–N). Its outer lateral side with two pec-tens; basal pecten consists of strong teeth; distal pecten consists of fine setulae (Fig. 1N). Ventral margin of claw with several denticles on its basal portion (Figs. 1 M–N).
Antenna I rod-like, elongated (its length is approximately equal to six diameters of the antennular body base), slightly curved (Figs. 1 A–B, O–P). Antennular body covered by numerous fine long hairs and transverse rows of minute denticles. Antennular sensory seta slender, arising almost at middle of antennular body. Nine short aesthetascs subequal in size (Figs. 1 O–P).
Antenna II large, typical of moinids (Figs. 1 A–B, R–S). Its coxal part with two setulated sensory setae unequal in length (Fig. 1R). Basal segment robust, with short distal spine on outer surface between exopod and endopod, and with a long seta on inner surface (Figs. 1A, R–S). Basal segment covered by numerous transverse rows of fine denticles and hairs. Antennal branches elongated (Figs. 1 R–S). Exopod four-segmented, slightly longer that threesegmented endopod, all segments cylindrical, covered by transverse rows of denticles and hairs. 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.
Thoracic limbs: five pairs (Figs. 2 A–H).
Limb I with elongate setulated corm and ovoid epipodite (Fig. 2A: epp). Inner distal lobe, or endite 5 (in terms of Kotov 2013) with a single anterior seta (Figs. 2 A–B: 1) covered by short setulae, and two posterior soft setae (Fig. 2A: a–b). All posterior soft setae in the limb I bisegmented and densely covered by long setulae. Endite 4 with a single anterior seta (Figs. 2 A–B: 2) and a single posterior soft seta (Fig. 2A: c). Endite 3 without anterior setae and with two posterior setae (Fig. 2A: d–e). Endite 2 with three posterior soft setae (Fig. 2A: f–h). Two ejector hooks of remarkably different size (Fig. 2A: ejh).
Limb II with ovoid large epipodite (Fig. 2C: epp). Exopodite (Fig. 2C: ext) as elongated, densely setulated lobe bearing a single soft seta and a small setulated soft lateral seta of unknown homology. Endites e5–e2 form a corm of limb II. Endite 5 with two posterior soft setae (Fig. 2C: a–b); endite 4 with a single posterior soft seta (Fig. 2C: c); endite 3 also with a single posterior soft seta (Fig. 2C: d). The homology of the setae located on the edge of the gnathobase (endite 1) is unclear. It seems that endite 2 itself includes only a small posterior soft seta with small sensillum near its base (Fig. 2C: e). So-called “beating seta” (in terms of Kotov et al. 2005) (Fig. 2C:?) and a small seta near its base are separated via a shallow incision (Fig. 2C). Also, they are separated by an incision from gnathobase body. Gnathobase (endite 1) with two clear rows of setae (Figs. 2 C–D); there are three anterior setae (Figs. 2 C–D: 1–3) and 16 posterior setae (Figs. 2 C–D: a–p) that form the gnathobase filter plate. Seta 1 (located near “beating seta”) long, mostly unilaterally covered by long setulae. Setae 2 and 3 significantly shorter, located in the basal corner of the gnathobase; seta 2 armed by robust short setulae, and seta 3 with relatively long setulae (Figs. 2 C–D).
Limb III with large ovoid epipodite (Fig. 2E). Exopodite almost rectangular, bearing four distal and two lateral setae (Fig. 2E). Inner distal portion of limb with three endites: endite 5 with a single posterior (Figs. 2 E–F: 1) and a single anterior (Figs. 2 E–F: a) setae; endite 4 with two posterior setae (Figs. 2 E–F: b–c) and with single anterior seta (Figs. 2 E–F: 2), endite 3 with a single anterior (Figs. 2 E–F: 3) and four posterior setae (Figs. 2 E–F: d–g). All other parts of limb inner margin as a single large lobe (gnathobase), bearing numerous setae (Figs. 2 E–F). A single anterior seta (Figs. 2 E–F: 4) in its distal corner.
Limb IV with large ovoid epipodite (Fig. 2G). Exopodite, similarly to that in limb III, with four distal and two lateral setae. Inner distal portion of this limb with two endites: distal endite with an anterior seta (Fig. 2G: 1) and a posterior seta (Fig. 2G: a); and next endite with an anterior seta (Fig. 2G: 2) and two posterior setae (Fig. 2G: b–c). Most part of the limb inner portion is represented by the gnathobasic filter plate, consisting of numerous setae.
Limb V with an elongated pre-epipodite (Fig. 2H: pep) and a large ovoid epipodite (Fig. 2H: epp). Large ovoid exopodite (Fig. 2H: ext) provided with a large distal, and a small apical setae. Inner limb portion as a flat setulated ovoid lobe and two unequal setae (Fig. 2H: 1–2) of unclear homology.
Ephippial female (Figs. 3A, 4D, 5 A–F). Characters of ephippial female as in parthenogenetic female except for the dorsal portion of valves which is modified into a dark brown ephippium, containing two resting eggs (Fig. 3A, 5A). Dorsal part of valves with a reinforced dorsal wrinkled, chitinous plate (Figs. 5 A–B, E–F). Micro sculpture of this plate is visible only under SEM and represented by small polygons (Figs. 5B, F). In lateral view, macro sculpture of anterior portion of ephippium and eggs chamber consists of polygonal protruding knobs with wavy edges; they are well visible also under light microscope (Figs. 4D, 5A, C–F). In posterior and ventral portion of ephippium, macro sculpture represented by elongated protuberances with smooth edges or anastomosing lines (Fig. 5A).
Male (Figs. 3 B–M, 4E–G). In lateral view, body ovoid, more elongated as compared to female (body height/ length about 0.55). Dorsal margin of valve slightly elevated above head; posteroventral angle distinct (Figs. 3B, 4E).
Head more elongated than in female, also covered by fine hairs (Figs. 3B, 4E). Dorsal head pores absent. Compound eye large, ocellus absent.
Labrum as in females (Fig. 3C).
Valve ovoid, more elongated than in female (Figs. 3B, 4E). Its anterior surface also covered by fine hairs (longer than hairs in females) (Figs. 3B, D, 4 E–G).Armature of ventral margin of valve as in female (Figs. 3 D–F). Setulated curved hooks located in the dorsal most portion of posterior margin of valve (Fig. 3G).
Thorax relatively long, abdomen short (Fig. 3B).
Postabdomen in general as in female (Fig. 3H), but denticles on lateral sides near base of claws are not grouped as in basal pecten of the female (Figs. 3 H–I). Gonopore opens on lateral surface of postabdomen at some distance from base of postabdominal claws (Fig. 3H).
Antenna I significantly longer than in female (Fig. 3B, J), curved, covered by tiny hairs and transverse rows of minute denticles. Long antennular sensory seta, arising from the proximal quarter of the antennula (Fig. 3J). Male seta more robust, smaller and located near sensory seta (Fig. 3J). Apical tip with two parts: first one with nine short aesthetascs, and the second one with four thick hooks (Fig. 3J).
Limb I in general as in female, but with a large, curved copulatory hook (Figs. 3 K–M). Exopodite absent (Fig. 3K). Stiff seta 1 of male limb I thick, with blunt tip (Figs. 3 K–L).
Size. Adult parthenogenetic females up to 1.15 mm in length; ephippial females up to 1.10 mm in length; adult males up to 0.70 mm in length.
Variability. In the specimens from Haiti investigated by us, no significant variability was found except for the size of the brood pouch in the parthenogenetic females. But Goulden (1968) reported a significant variability in the armature of the ventral side of the postabdominal claw. According to him, individuals from Kansas and Haiti (from original Richard’s type material (see Goulden 1968, p. 45, figs. b, d–e)) have thin and small denticles on the ventral side of the proximal portion of postabdominal claw. Goulden also found an individual from Kansas with a pecten of large denticles on one side of postabdominal claw, and only small denticles on the other side. It could be a sign that the size of denticles in the basal pecten of postabdominal claw may be subject to variability.
Also, according to Goulden (1968), a significant variability affects the development of tiny hairs on head and valves and on male antenna I. Hairs covered only a posterodorsal portion of the head and the anteroventral portion of valves in parthenogenetic females from Haiti, Texas, and Central California, however the head and valves of parthenogenetic females from Arizona, and Oregon were completely covered by hairs, and finally, he found tiny hairs on the dorsal portion of the postabdomen in a population from Kansas (Goulden 1968, p. 45, figs. 18b, d). Richard did not illustrate hairs on head and valves of M. wierzejskii from Haiti (Richard 1895: p. 196, figs. 9–10), and armature of dorsal portion of postabdomen seems to be represented by fine setulae rather than long hairs (Richard 1895: p. 197, fig. 11). But Richard could overlook hairs on head and valves in parthenogenetic females, as the resolution of tools used at his time were significantly lower that recently.
We found parthenogenetic females with hairs on head and valves in Richard’s type specimens. According to our observation, armature of dorsal portion of postabdomen in parthenogenetic females from type material is represented by short setulae rather than long prominent hairs. All males in our material have antenna I with short hairs (see above). There is a chance that Goulden was dealing with males of another taxon, as usually several species of the Moinidae could coincide in the same water bodies and produce males simultaneously. Even in Richard’s material (tubes DGF 0800 and DGF 0806) we found specimens belonging to Moina micrura complex (parthenogenetic females, males, and ephippial females). In fact, it is not easy to discriminate males of M. wierzejskii and M. micrura complex under stereoscopic microscope before dissection. Males of M. wierzejskii may be easily distinguished from the males of M. micrura complex under a light microscope by presence of fine hairs on outer surface of valves and ungrouped denticles on posterior portion of ventral margin. Males of M. micrura complex have no hairs on valves, and denticles on posterior portion of ventral margin are grouped (Elías-Gutiérrez et al. 2019). At the same time, discrimination of males of these two taxa based on armature of postabdominal claw maybe problematic due to its variability.
Taxonomic remarks. In contrast to Goulden (1968), Smirnov (1976) and Kotov & Ferrari (2010), we do not consider Moina platensis Birabén, 1917 as a junior synonym of M. wierzejskii. Birabén (1917: p. 266 fig. 7) illustrated the antenna I of male bearing very long hairs (comparable in length or even longer than the diameter of the antennular body), while in specimens from Richard’s material, hairs on male’s antenna I are very short (Fig. 3J). At the same time, a parthenogenetic female, illustrated by Birabén (1917: p. 265 fig. 4–6), had an ovoid (almost spherical) shape of body, and a postabdomen with prominent long hairs on its dorsal edge. M. platensis share these features with M. affinis Birge, 1893, or even with M. micrura var. ciliata Daday, 1905 (Goulden 1968; Smirnov 1976). Both these taxa are known from the New World but, in contrast to M. wierzejskii, their gamogenetic females bear a single egg in the ephippium, and they belong to the small-sized moinids.According to Birabén (1917: p. 264), “adult female length of M. platensis is between 1.75 mm and 1.20 mm; body width varies according to greater or less extension of embryo’s development”, so, based on original measurements, this taxon belong to the large-bodied moinids. At this stage, we offer to consider M. platensis as “species inquirenda ”.
Distribution and ecology. Illustrated records of M. wierzejskii are known from Haiti (Richard 1895; Goulden 1968) and Arizona and Kansas (Goulden 1968). M. wierzejskii was also found in Mexico (Elías-Gutiérrez et al. 1999), but these records were not supported by illustrations. Records from Argentina (e.g. Olivier 1962) were not supported by original illustrations. Olivier (1962) just reproduced figures of Richard (1895). The accepted distribution range of M. wierzejskii includes South America (Goulden 1968; Smirnov 1976; Paggi 1997; Echaniz & Vignatti 2010; Battauz et al. 2013), but this idea must be specially checked from an integrative taxonomy approach due to the high cryptic diversity showed for the genus (Bekker et al. 2016; Elías-Gutiérrez et al. 2019; Montoliu-Elena et al. 2019).
Preliminarily, we may conclude, that M. wierzejskii inhabits temporary pools, roadside ditches and ponds in tropical and subtropical regions of the New World.
description: Published as part of Neretina, Anna N., Kirdyasheva, Anna G. & Kotov, Alexey A., 2020, Position of Moina wierzejskii Richard, 1895 (Crustacea: Cladocera) within the genus Moina Baird, 1850 in the light of new morphological data, pp. 506-522 in Zootaxa 4820 (3) on pages 507-516, DOI: 10.11646/zootaxa.4820.3.5, http://zenodo.org/record/4398150