Daphnia turbinata Sars, 1903

Zuykova, Elena I., Sheveleva, Natalia G. & Kotov, Alexey A., 2019, Redescription of Daphnia turbinata Sars, 1903 (Crustacea: Cladocera: Daphniidae), Zootaxa 4658 (2), pp. 317-330 : 319-327

Daphnia turbinata Sars, 1903

( Figs 2 – 6 )

Daphnia longispina var. turbinata Sars, 1903: 156 – 168 , Pl. 4: Figs. 3, 3a – c .

Daphnia turbinata Sars in Glagolev 1995: 58 , Pl. 48: Figs 16 – 17; Ayushsuren et al. 2013: 125, Fig. 4 .

not D. longispina turbinata Sars in Manujlova 1964 : Fig. 36: fragment 21.

Type locality. “Lake Kurtu-Kol”, the basin of Teletskoye Lake , Altai Republic, Russia. It is difficult to find this water body in recent maps, this is a non-drainage lake in the basin of the Bashkaus River , affluent of the Chulymshan River inflowing Teletskoe Lake ( Golubtsov & Malkov 2007), most probably, this is a small lake locally named as “Kara-Kol” (N50.5619°, E87.8874°), from which the Kurtu-Kol River flows out .

Type material. GOS F 9524 and GOS F 9524. These two slides with locality labelled as “ Altay ” represent, most probably, a type series, as Sars (1903) has the material from a single lake and never reported on any subsequent findings of D. turbinata from this region.

Material studied. Russia. Parthenogenetic females from un-named lake 2 near Kosh-Agach (N50.0105º, E88.61234º, 1745 m.a.s.l.), Altai Republic, coll. in 10.08.2015 by Y.R. Galimov, AAK M-3169 . Parthenogenetic females from unnamed lake 1 near Kosh-Agach (N50.0175º, E88.60416º, 1754 m.a.s.l.), Altai Republic, coll. in 10.08.2015 by Y.R. Galimov,AAK M-3173 . Parthenogenetic females from unnamed lake (N50.24367º, E89.46833º, 2322 m.a.s.l.), Tyva Republic, coll. in 11.08.2015 by Y.R. Galimov, AAK M-3170 . Parthenogenetic females from unnamed pond 3, the Todzha Depression (N52.43º, E96.3º, 922 m. a.s.l.), Tyva Republic, coll. by E.I. Zuykova, EIZ, no number . Mongolia. Parthenogenetic females from Urt Tsaramiin Nuur (Lake) (N47.68809º, E102.691º, 1352 m.a.s.l.) near Hatgal , Huvsgul Aimag, coll. in 02.08.2005 by Ch. Jersabek, AAK 2008-018 . Males, ephippial & parthenogenetic females from Zhaakhan Nuur (Lake) (N48.334º, E96.0618º, 1984 m.a.s.l.), Zavkhan Aimag, coll. by Ch.Ayushsuren, AAK 2018-083 . Parthenogenetic females from Khongor Nuur (Lake) (N48.50786º, E90.60475º, 2376 m.a.s.l.), Bayan-Ölgii Aimag, coll. in 24.07.2008 by D.P. Karabanov, AAK M-0774 . Parthenogenetic females from Khargal Nuur (Lake) (N49.9375º, E102.7233º, 1066 m.a.s.l.), Bulgan-Orkhon Aimag, coll in 24.07.2009 by D.P. Karabanov, AAK M-1322 . Parthenogenetic females from a pond (N51.08263º, E99.70533º, 1588 m.a.s.l.) SE Shar Nuur (lake) near Hanh, Huvsgul Aimag, coll. in 28.07.2005 by Ch. Jersabek, AAK 2008-013 .

Redescription. Adult parthenogenetic female. Body pigmented in yellow-brown in different extension, and level of pigmentation varies even among specimens from same population ( Fig. 2A – B ), in some samples all specimens were pigmented. Body subovoid in lateral view, maximum height of head approximately equal to maximum body height in middle of valves ( Fig. 3A – B ). Dorsal margin of valves slightly and regularly convex, no depression between head and rest of body. Postero-dorsal body portion remarkably narrowing distally to postero-dorsal angle supplied with a very long caudal spine, ventral margin regularly convex. All surface of head and valves with a wellvisible, specially rough as compared to other longispina -like taxa, sculpture of anastomosing lines ( Fig. 2D – E ).

Head very wide, with short rostrum, its tip not bent ( Fig. 3E, F ); posterior margin of head short, with a very low prominence in middle ( Fig. 2E ); ventral margin of head almost straight ( Fig. 2D ) to regularly convex ( Fig. 2E ) or even with a smooth angle in the antero-ventral surface ( Fig. 3B ). Compound eye medium-sized, ocellus minute and located closer to eye than to base of antenna I. Labrum with a fleshy main body and a large, setulated distal labral plate.

Carapace subovoid, spinulae ( Fig. 3G ) occupy the posterior half of dorsal margin and half to more than half of ventral margin. No setae at ventral margin, in posteriormost portion of ventral margin (on its inner face) a row of spinulae, but no setae ( Fig. 3 H–I).

Abdomen relatively short, consisting of four segments. The first (basal most) abdominal segment with especially long (up to 2.5–2 times longer than postabdominal claw) process bent anteriorly; the second segment with a long process approximately as long as postabdominal claw; the third segment with a short process; the fourth segment without a projection; on all processes there are rows of minute setulae ( Fig. 3J ).

Postabdomen elongated, tapering distally, with ventral margin slightly convex, lacking of setulae ( Fig. 3J ). Preanal margin long (remarkably longer than anal plus postanal portions of postabdomen), almost straight, its region densely covered by minute setulae ( Fig. 3K ). Pre-anal angle absent, postanal angle rounded. Numerous (up to 15) paired spines on postanal and anal portion, their size continuously increasing distally. Postabdominal seta longer than preanal margin. Postabdominal claw slightly and regularly bent, with a pointed tip ( Fig. 3L ). On ventral (convex) side, two bunches of minute setulae; on dorsal (concave side), three successive pectens fluently turned each to other.

Antenna I body fully reduced ( Fig. 3F ), nine aesthetascs (somewhat unequal in size) protruding immediately from head surface, their tips do not reach tip of rostrum, antennular sensory seta fine, arise immediately from head surface instead of mound of the antenna I.

Antenna II with coxal part possessing two short sensory setae of different length, its basal segment elongated, with a distal sensory seta on its posterior face and minute distal spine at its anterior face ( Fig. 3M ). Antennal branches with series of minute setulae. Spines on apical segments rudimentary. Antennal formula: setae 0-0-1-3/1-1-3. Chitinous insertion within distal segment of each swimming seta relatively far from joint with proximal segment ( Fig. 3N ).

Limb I without accessory seta; outer distal lobe ( Fig. 4A : ODL) with a long seta bilaterally armed distally with minute setulae, and a thin, short (length about 2–3 diameters of ODL) seta bilaterally setulated distally; inner distal lobe ( Fig. 4A : IDL), or endite 4, with a single, long anterior seta ( Fig. 4A : 1), bilaterally armed by minute setulae distally. Endite 3 with a relatively long anterior seta 2, armed with minute setulae, and two long posterior setae (ab). Endite 2 with a very short anterior seta 3, and two posterior setae (c–d). Endite 1 with a relatively small anterior seta 4 and four posterior setae (e–h). Two ejector hooks ( Fig. 4A : ejh) of somewhat different length.

Limb II with distal portion as a large lobe (presumable exopodite, Fig. 4B : ext) bearing a large, soft, distal seta, and a large, soft, lateral seta of similar length. Four endites bearing five setae; among them, a stiff, anterior seta ( Fig. 4B : 1) about 2/3 length of each of two other setae on this endite, armed with fine setulae distally. Gnathobase with four anterior setae ( Fig. 4B : 1–4) and about 10 posterior setae of gnathobasic ‘filter plate’ (their number is slightly varying among individuals).

Limb III with a setulated pre-epipodite ( Fig. 4C : pep), subglobular epipodite ( Fig. 4C : epp) and a flat exopodite ( Fig. 4C : ext) bearing four distal ( Fig. 4C : 1–4) and two lateral setae ( Fig. 4C : 5–6). Inner-distal portion of limb with four endites: endite 4 with a specially long anterior seta ( Fig. 4 C–D: 1) and a single posterior seta (a); endite 3 with a single anterior seta (2) and a single posterior seta (b); endite 2 with a small anterior seta (3) and two posterior setae; endite 1 with a large anterior seta (4) and four posterior setae. The rest of limb inner-distal portion as a singular large lobe, bearing numerous posterior soft setae, and a single, relatively long anterior seta ( Fig. 4 D–E: 1), this limb part represents a modified gnathobase III.

Limb IV with a setulated pre-epipodite ( Fig. 4F : pep), ovoid epipodite ( Fig. 4F : epp) and wide, flat exopodite ( Fig. 4F : ext), with protruding and setulated inner-distal angle, and bearing four distal ( Fig. 4F : 1–4) and two lateral setae ( Fig. 4F : 5–6). Inner-distal portion of this limb with completely fused endites, distally with two setae of unclear homology, the most part of limb inner margin is a gnathobase filter plate consisting of numerous posterior setae ( Fig. 4G ).

Limb V with a globular epipodite ( Fig. 4H : epp); triangular exopodite ( Fig. 4H : ext) supplied with two small distal setae ( Fig. 4H : 1–2) and a large lateral seta ( Fig. 4H : 3). Inner limb portion as an ovoid flat lobe, with setulated inner margin and a single, large seta.

Juvenile female. Body more elongated, head relatively smaller, eye relatively large as compared to adult female ( Fig. 2C ).

Ephippial female. Shape ( Fig. 2F – H , 3C – D ). In general body external shape as in parthenogenetic female, but dorsal carapace portion modified to ephippum pigmented in brown; egg locule region with especially dark pigmentation ( Fig. 2F – G ); dorsal margin of carapace straight, dorsal wall of carapace additionally chitinised, forming a dorsal plate, covered by minute spinulae ( Fig. 2H ). Ephippium with two resting eggs, axes of which sub-perpendicular to its dorsal margin; egg chambers separated from each other, most part covered with sculpturing of polygonal cells; postero-dorsal portion of valves with caudal spine incorporated into ephippium.

Adult male. Body low, elongated, narrowing posteriorly; dorsal margin of valves almost straight, not elevated above head; no depression between head and valves; postero-dorsal angle distinct, with a long caudal spine ( Fig. 5A ).

Head. Posterior head margin straight, with a very low step-like prominence in proximal portion of margin ( Fig. 5B ). Postero-ventral head angle as a rudimentary rostrum. Ventral margin of head almost straight, anterior-most extremity not occupied with optic vesicle, no supra-ocular depression posteriorly to it. Eye not specially large, anterior most head extremity not fully occupied with optic vesicle, ocellus very small. Labrum with a large distal labral plate ( Fig. 5C ).

Valve with antero-ventral portion rounded; all ventral margin with numerous setae submarginally on inner face of valve ( Fig. 5A , D–E). Posterior half of each dorsal and ventral margin with small marginal denticles ( Fig. 5 F–G); in contrast to female, inner face of valve posterior margin with rare setae and small setulae between them ( Fig. 5H ).

Abdomen with rudimentary mounds on first and second segment; low mound on third and fourth segments ( Fig. 5I ).

Postabdomen shape and armature in general as in female, but preanal margin longer.About 10 paired teeth large (distalmost 2–3 times longer than claw diameter) strongly increasing in size distally ( Fig. 5J ). Gonopore opens laterally, without a genital papilla. On outer surface of postabdominal claws, pectens consist of thin spinules only; two bunches of minute setulae on claw convex side.

Antenna I elongated, straight ( Fig. 5K ); nine aesthetascs of different length located terminally, among them, largest aesthetasc as long as antenna I maximum diameter. Antennular sensory seta ( Fig. 5K : ass) of moderate length (about 0.7 diameter of antenna I), located subterminally, projects beyond tip of antenna I body; male seta (flagellum) ( Fig. 5K : mas) distally on antenna body on a low post-aesthetasc process, remarkably shorter than an aesthetasc, with curved tip.

Antenna II ( Fig. 5L ) as in female.

Limb I ( Fig. 6 A–B) with outer distal lobe large, cylindrical ( Fig. 6A : ODL), bearing a small seta and a very large seta ( ODL is not illustrated here); inner distal lobe with a relatively long, bent copulatory hook, and two setae of different size ( Fig. 6B : 1 and 1’); endite 3 with four setae (additional seta marked as 2’ in Fig. 6A ), setae 2 and 2’ equally long, seta 3 remarkably larger than in female, seta 4 as in female.

Limb II ( Fig. 6 C–D) with distalmost endite with a modified anterior seta 1, unilaterally armed by long, relatively thin setulae ( Fig. 6D ); gnathobase seta 1 larger as compared to female, but also small.

Limb III ( Fig. 6 E–F) in general as in female, but exopodite seta 2 longer as compared to female. Limb IV ( Fig. 6 G–H) as in female. Limb V exopod with all setae armed by longer setulae, seta on inner face also supplied with longer setulae ( Fig. 6I ).

Size. Parthenogenetic females 0.87–2.36 mm in Zhaakhan Nuur, 0.78–2.54 mm in Khargal Nuur (without caudal spine) (up to 2.4 mm without caudal spine according to Sars, 1903); adult males 1.78–1. 91 mm in Zhaakhan Nuur. Differential diagnosis. Sars (1903: 167) justifiably pointed that this taxon could be distinguished by “the unu- sually large and procumbent head and the form of the carapace, which rapidly tapers posteriorly, giving the whole animal, seen laterally, a somewhat turbinated form”. D. turbinata could be discriminated from any other longispina - like taxa due to its well-visible, rough reticulation.

But the strongest difference from other members of the D. longispina -group concerns the male morphology: the specially short and thick male seta (flagellum) in combination with a relatively large sensory seta of antenna I is a unique trait of D. turbinata among the longispina -like taxa.

Distribution. D. turbinata has a relatively narrow distribution range as compared to other members of the D. longispina group. According to our samples, it is known from the Altai-Sayan mountain region (exactly, from Eastern Sayan, Altai, Mongolian Altai and Khangai mountains). There is a chance that it will be found in the mountains of some other countries of Middle Asia (first of all, Kazakhstan) and NW China. Records from Baikal region need to be checked, at least, we did not find D. turbinata in our samples from this region ( Fig. 1 ). Unfortunately, previous literature sources are mainly useless for understanding of its distribution range, as the quality of identification is unknown. For example Manujlova (1964: Fig. 36, fragment 21) most probably dealt with other longispina -like taxon instead of D. turbinata . The latter apparently belongs to the mountain endemic faunistic complex according to Kotov (2016).

Figures

FIGURE 1. Map of North East Asia. Empty circles: all samples analysed. Red circles: localities where populations of D. turbinata are found.Initial map was made based on free spatial GIS data from http://www.naturalearthdata.com as the layers.

FIGURE 2. Optical photos of Daphnia (Daphnia) turbinata Sars, parthenogenetic (A–E) and ephippial (F–H) females from Khargal Nuur (Lake) (A–D) and Zhaakhan Nuur (Lake) (E–H), Mongolia. A–B, adult parthenogenetic female. C, juvenile female. D–E, head of adult parthenogenetic female. F, ephippial female. G, ephippium. H, dorsal portion of ephippium. Scale bars: 1 mm for A–C, F–G; 0.1 mm for D–E, H. Scale bars: 1 mm for A–C, F–G; 0.1 mm for D–E, H.

FIGURE 3. Daphnia (Daphnia) turbinata Sars, female from Zhaakhan Nuur, Mongolia.A–B, parthenogenetic female, general view. C–D, ephippial female, general view. E, head. F, rostrum. G, valve ventral margin, posterior portion. H, postero-ventral valve margin. I, postero-ventral and postero-dorsal margin in region of caudal spine base. J, postabdomen and abdomen, general view. K, armature of anal margin. L, postabdominal claw. M, antenna II. N, apical seta of antenna II. Scale bars: 1 mm for A–E, J; 0.1 mm for F–I, L–N; 0.01 mm for K.

FIGURE 4. Daphnia (Daphnia) turbinata Sars, thoracic limbs of parthenogenetic female from Zhaakhan Nuur, Mongolia. A, limb I. B, limb II. C, limb III. D–E, inner-distal portion of limb III. F, limb IV. G, inner-distal portion of limb IV. H, limb V. Scale bars 0.1 mm.

FIGURE 5. Daphnia (Daphnia) turbinata Sars, adult male from Zhaakhan Nuur, Mongolia. A, general view. B, head. C, labrum. D–E, anterior portion of valve ventral margin. F-G, ventral margin, posterior portion. H, posteriormost portion of ventral margin, inner side. I, postabdomen and abdomen, general view. J, distal portion of postabdomen and abdomen with postabdominal claw. K, antenna I. L, antenna II. Scale bars 1 mm for A–B, J; 0.1 mm for C–L.

FIGURE 6. Daphnia (Daphnia) turbinata Sars, thoracic limbs of adult male from Zhaakhan Nuur, Mongolia.A, limb I, general view. B, limb I, inner distal lobe. C, limb II. D, single stiff seta on its inner-distal portion. E, limb III. F, inner-distal portion of limb III. G, limb IV. H, inner-distal portion of limb IV. I. limb V. Scale bars 0.1 mm.