36 research outputs found
FIGURE 9 in A new species of the genus Ceriodaphnia Dana, 1853 (Cladocera: Daphnidae) from Eastern Siberia (Russia) that combines morphological features of two species groups
No full textFIGURE 9. Ceriodaphnia nikolaii sp. nov. from an oxbow of the Lena River near city of Yakutsk, Republic of Sakha (Yakutia), Asian Russia. A, ephippial female, lateral view. B, C, E, F, adult parthenogenetic female, lateral view. D, juvenile female, lateral view. Scale bars: 1 mm for E, F; 0.1 mm for A, D, F.Published as part of Garibian, Petr G., Andreeva, Lena V. & Kotov, Alexey A., 2023, A new species of the genus Ceriodaphnia Dana, 1853 (Cladocera: Daphnidae) from Eastern Siberia (Russia) that combines morphological features of two species groups, pp. 247-270 in Zootaxa 5284 (2) on page 258, DOI: 10.11646/zootaxa.5284.2.2, http://zenodo.org/record/792331
Ceriodaphnia nikolaii Garibian & Andreeva & Kotov 2023, sp. nov.
No full textCeriodaphnia nikolaii sp. nov. (Figs. 9–16) Etymology. The taxon is named after our teacher, Prof. Nikolai N. Smirnov, who initiated great progress in the studies of cladocerans in Eurasia and in the world and collected the type series. Type locality. An un-named oxbow of the Lena River, City Yakutsk, Republic of Sakha (Yakutia), Russia (62.0˚N, 129.8˚E). Type material. Holotype. A parthenogenetic female, MGU Ml 266 at the Collection of Zoological Museum of M. V. Lomonosov Moscow State University, Moscow, Russia. Allotype. An adult male, MGU Ml 267. Paratypes. Ten parthenogenetic females, six ephippial female and seven adult males, MGU Ml 268. Several parthenogenetic, ephippial females and males, AAK 1999-045. Adult parthenogenetic female. General (Figs. 9b,c,e,f). Body subovoid in lateral view, with maximum height in middle of valves. Dorsal margin interrupted by a depression in posterior head portion. Dorsal and ventral portion ovoid, poster-dorsal angle present, with small caudal spine. Postero-dorsal angle well-developed, sometimes represented by a short caudal spine, valve margin from the former to anterior margin uniformly rounded. In dorsal view, body subovoid and elongated. Head (Figs. 10a–g) small, ovoid, without rostrum, with a strong depression in posterior head half; small dorsal head pore in this depression. Dorsal head pore round; supraocular dome surround relatively big compound eye; ocellus minute. Labrum (Fig. 10g) quadrangular, with a wide fleshy main body and large setulated labral plate. In dorsal view, fornices from rounded to slightly projected. Valve large and ovoid (Figs. 11a–f); ventral portion with long setae at inner margin (Figs. 11a–b); postero-ventral portion with a row of short setae, short series of setules between them (Fig. 11c); two relatively long setae in dorsal most portion (Fig. 11d–f). Abdomen (Figs. 12b, h, i) short consisting of four segments, first segment having a long abdominal projection. Postabdomen (Figs. 12a–i) elongated, tapering distally. Ventral portion straight. Preanal margin from slightly to strongly projected and angled, postanal angle rounded. Postanal and anal margin bearing 8–9 teeths of different size. Preanal, anal and postanal portion covered by short series of minute setules. Postabdominal seta as long as postabdomen. Postabdominal claw elongated, curved, with pointed tip (Figs. 13a–h). Outer portion of dorsal margin with three successive pectens. First pecten with thin setules, second pecten consisting of twelve to twenty six stout teeth with variable size, and third pecten bearing numerous minute setules, not reaching the tip of claw. Antenna I (Figs. 10g,h) short and cylindrical. Antennular seta longer than antenna I body, mostly same in size with longest aesthetascs. Antenna II (Figs. 11g –i) with a narrow coxal part bearing two sensory setae. Basal segment of antenna II cylindrical elongated and covered by rows of small setules. Antennular branches long, approximately same in size, exopodite with four setulated segments, endopodite consist of three setulated segments. Antennal formula: 0-0-1- 3/1-1-3, second segment of exopodite bearing one short spine, distal part of basal segment with one short spine. Limb I (Figs. 14a and 15a) with a bilaterally setulated accessory seta. Outer distal lobe (ODL) bearing a very long, naked seta and a short seta setulated in distal part. Inner distal portion (endite 4) with a single anterior and two posterior setae of different size. Endite 3 with a single, long anterior seta (1) and two posterior setae (a–b); endite 2 with a single anterior seta (2) and two posterior setae (c–d); endite 1 with a single, short anterior seta (3) and four posterior setae (f–h). Two ejectors hooks subequal in size (Figs. 14a and 15a). Maxillar process absent. Limb II (Figs. 14b and 15b–d) with an ovoid epipodite (epp) an elongated exopodite (ext) bearing two long bilaterally setulated setae. Endite 5 with a short anterior seta (1) and two long, bilaterally setulated posterior setae (a–b); endite 4 with a single long (longest one) stiff anterior setae (2) and a long posterior seta (c); endite 3 with a single short anterior seta (3) and no posterior setae; endite 2 with a short anterior seta modified into sensillum (4) and a single posterior seta (d). A seta on unclear homology near gnathobase. Endite 1(e1) = gnathobase with two rows of setae. Anterior row consists of four setae: setae 1 presented by a small sensillum; seta 2 very long and setulated; seta 3 shorter than seta 2; seta 4 short. Posterior row with eight setae of different morphology. Limb III (Figs. 14c and 15e–h) with a subovoid and elongated prepipodite (pep) and ovoid epipodite (epp). Exopodite (ext) with two lateral (5–6) and four distal setae (1–4); distal segment of seta 1 and seta 2 thin, proximal part of seta 2 with a row of strong setules. Limb inner distal portion represented by five endites: endite 4 with a single anterior (2) and a single posterior (b) seta; endite 3 with a short anterior seta (3); endite 2 with a very short anterior seta (4); endite 1 (gnathobases) represented by a large lobe with a long distal anterior seta (1) and two small, stiff anterior setae (2–3), posterior portion represented by numerous long posterior setae. Limb IV (Figs. 14d and 15i) with an elongated prepipodite (pep) and ovoid epipodite (epp). Exopodite (ext) bears two lateral setae (5–6) and four distal setae (1–4); distal segment of seta 1 thin. Inner limb portion with two setulated anterior setae (1–2); posterior portion bears numerous long posterior setae. Limb V (Figs. 14e and 15j) with elongated epipodite (epp), exopodite (exp) triangular, with two distal setae of different size (1–2) and a large lateral seta (3). Inner portion of limb V with a setulated margin and a large distal seta. Juvenile female (Fig. 9d). Body subovoid and elongated; dorsal margin slightly convex; postero-dorsal and ventral portion round. Head round, with large compound eye and small ocellus. Dorsal portion with great depression between head and body; dorsal part of headshield with protruding dorsal head pore. Ephippial female (Figs. 9a and 10a). Body subovoid, valves modified into ephippium with a single resting egg; in lateral view ephippium with expressed reticulation; ephippium without lateral projections. Adult male (Fig. 16a,c–i). Body subovoid and elongated, dorsal margin straight, postero-dorsal and ventral portion rounded. Postero-ventral angle rounded. Head (Fig. 16a,c) relatively small, without rostrum. Compound eye large and ocellus small. Dorsal portion of head shield in lateral view with high depression between head and body; dorsal head pore present. Labrum (Figure 16c) as in parthenogenetic female. Valve (Fig. 16a) as in parthenogenetic female. Abdomen (Fig. 16e) with four setulated segments lacking any process, covered by minute setules. Postabdomen (Fig.16e,f) elongated, subrectangular; ventral margin convex.Dorsal margin convex, preanal angle projected. Postanal and anal portion with about seven strong teeth. Gonopore opens subdistally on postabdomen. Postabdominal claw as in female. Antenna I (Fig. 16c,d) cylindrical, long, with nine short aesthetascs. Sensory seta relatively short (shorter than longest aesthetascs) located subdistally on anttenna I body. Flagellum located distally, longer than antenna I body. Antenna II (Fig. 16c) same as in parthenogenetic female. Limb I (Fig. 16g,h) with a cylindrical outer distal lobe bearing a long seta and a short setulated seta. Inner distal lobe with a copulatory hook and four seta of different size. Morphology of endites mostly same as in female, but endite 5 with an additional seta. Limb II (Fig. 16i) endite 4 with long modified anterior seta (distal part bilaterally setulated); endite 3 and endite 2 bearing anterior seta longer than female anterior seta. Juvenile male (Fig. 16b). Body subovoid, dorsal margin relatively straight, postero-dorsal and ventral portion round. Head round, without rostrum; antenna I cylindrical with a long thick sensory seta on the basal part and a relatively short flagellum (same in size as antenna I body). Size. Parthenogenetic female length 0.38–1.1 mm / height 0.23–0.8 mm; ephippial female length 0.88 mm / height 0.64 mm; male length 0.64–0.68 mm / height 0.35 mm. Differential diagnosis. This taxon belongs to the C. dubia s.lat. species group and has four diagnostic characters mentioned in the Introduction. The main diagnostic character is the presence of larger teeth on the postabdominal claw, but their length is c.a. half the claw diameter in C. dubia group, while c.a. a claw diameter in C. reticulata group. Presence of these teeth as well as rudimentary stiff (anterior) setae on the inner-distal portion of limb II differentiate well C. nikolaii sp.nov. from C. laticaudata-rotunda group lacking such teeth and having relatively long setae on limb II. In contrast to other taxa of the C. dubia group, parthenogenetic female of C. nikolaii sp.nov. has the preanal angle of postabdomen from slightly pronounced to greatly pronounced (similarly to that in Ceriodaphnia laticaudata), while in other members of C. dubia s.lat. the preanal angle is smoothed or slightly projected. In addition, male postabdomen in C. nikolaii sp.nov. has an expressed preanal angle in contrast to. dubia s.l. with a completely smoothed preanal angle; the shortest seta of IDL has a size similar to that of two other setae, while in the latter the shortest seta is clearly shorter than other setae of IDL. Distribution. C. nikolaii sp. nov. is known to date only from its type locality: an oxbow of the Lena River near city of Yakutsk. Perhaps it is an endemic species with a limited distribution (i.e. it is absent in any other numerous samples from Easter Siberia and Far East studied by the authors). Note that the majority of studied populations from Republic of Sakha (Yakutia) belonged to C. dubia s.l. instead of C. nikolaii sp. nov.Published as part of Garibian, Petr G., Andreeva, Lena V. & Kotov, Alexey A., 2023, A new species of the genus Ceriodaphnia Dana, 1853 (Cladocera: Daphnidae) from Eastern Siberia (Russia) that combines morphological features of two species groups, pp. 247-270 in Zootaxa 5284 (2) on pages 259-264, DOI: 10.11646/zootaxa.5284.2.2, http://zenodo.org/record/792331
FIGURE 10 in A new species of the genus Ceriodaphnia Dana, 1853 (Cladocera: Daphnidae) from Eastern Siberia (Russia) that combines morphological features of two species groups
No full textFIGURE 10. Ceriodaphnia nikolaii sp. nov. from an oxbow of the Lena River near city of Yakutsk, Republic of Sakha (Yakutia), Asian Russia. A, ephippial female, dorsal view. B, E, adult parthenogenetic female, dorsal view. F, G, head, lateral view. H, antenna I. Scale bars 0.1 mm.Published as part of Garibian, Petr G., Andreeva, Lena V. & Kotov, Alexey A., 2023, A new species of the genus Ceriodaphnia Dana, 1853 (Cladocera: Daphnidae) from Eastern Siberia (Russia) that combines morphological features of two species groups, pp. 247-270 in Zootaxa 5284 (2) on page 260, DOI: 10.11646/zootaxa.5284.2.2, http://zenodo.org/record/792331
FIGURE 7. Ceriodaphnia dubia s.l in A new species of the genus Ceriodaphnia Dana, 1853 (Cladocera: Daphnidae) from Eastern Siberia (Russia) that combines morphological features of two species groups
No full textFIGURE 7. Ceriodaphnia dubia s.l. adult male from an oxbow of the Don River near Stogovskoy village, Rostov Area, European Russia. A, lateral view. B, dorsal view. C, head, lateral view. Adult male from puddle, Mongun-Taiyginskyi District, Tuva Republic, Asia Russia. D, lateral view. E, head, lateral view. Scale bars 0.1 mm.Published as part of Garibian, Petr G., Andreeva, Lena V. & Kotov, Alexey A., 2023, A new species of the genus Ceriodaphnia Dana, 1853 (Cladocera: Daphnidae) from Eastern Siberia (Russia) that combines morphological features of two species groups, pp. 247-270 in Zootaxa 5284 (2) on page 256, DOI: 10.11646/zootaxa.5284.2.2, http://zenodo.org/record/792331
FIGURE 8. Ceriodaphnia dubia s.l in A new species of the genus Ceriodaphnia Dana, 1853 (Cladocera: Daphnidae) from Eastern Siberia (Russia) that combines morphological features of two species groups
No full textFIGURE 8. Ceriodaphnia dubia s.l. adult male from an oxbow of the Don River near Stogovskoy village, Rostov Area, European Russia. A, antenna I. C, postabdomen, lateral view. D, postabdomen claw, lateral view. F, maxilla. G, H, limb I. I, inner distal lobe of limb I. J, outer distal lobe of limb I. L, limb II. Adult male from a puddle in Mongun-Taiyginskyi District, Tuva Republic, Asian Russia. B, antenna I. E, postabdomen, lateral view. K, distal portion of limb I. Scale bars 0.1 mm.Published as part of Garibian, Petr G., Andreeva, Lena V. & Kotov, Alexey A., 2023, A new species of the genus Ceriodaphnia Dana, 1853 (Cladocera: Daphnidae) from Eastern Siberia (Russia) that combines morphological features of two species groups, pp. 247-270 in Zootaxa 5284 (2) on page 257, DOI: 10.11646/zootaxa.5284.2.2, http://zenodo.org/record/792331
FIGURE 6. Ceriodaphnia dubia s.l in A new species of the genus Ceriodaphnia Dana, 1853 (Cladocera: Daphnidae) from Eastern Siberia (Russia) that combines morphological features of two species groups
No full textFIGURE 6. Ceriodaphnia dubia s.l. adult parthenogenetic female from an oxbow of the Don River near Stogovskoy village, Rostov area, European Russia. A, limb I. C, D, limb II. E, limb III. F, seta 2 of limb III exopodite. G, seta 1 of limb III exopodite. H, limb IV. I, limb V. Adult parthenogenetic female from f laboratory culture of unknown origin. B, limb II. Scale bars 0.1 mm.Published as part of Garibian, Petr G., Andreeva, Lena V. & Kotov, Alexey A., 2023, A new species of the genus Ceriodaphnia Dana, 1853 (Cladocera: Daphnidae) from Eastern Siberia (Russia) that combines morphological features of two species groups, pp. 247-270 in Zootaxa 5284 (2) on page 255, DOI: 10.11646/zootaxa.5284.2.2, http://zenodo.org/record/792331
FIGURE 4. Bosminopsis africanus, female from from a in On the taxonomic status of Oriental populations of the genus Bosminopsis Richard 1895 (Crustacea: Cladocera)
No full textFIGURE 4. Bosminopsis africanus, female from from a lake in Khon Kaen Province, Thailand. A, maxilla I. B, limb I. C, limb II. D, limb II gnathobase. E, limb III. F, limb III inner-distal portion. G, limb IV. H, limb IV gnathobase. I, limb V. Scale bar denotes 0.1 mm.Published as part of Garibian, Petr G., Sanoamuang, La-Orsri & Kotov, Alexey A., 2021, On the taxonomic status of Oriental populations of the genus Bosminopsis Richard 1895 (Crustacea: Cladocera), pp. 261-279 in Zootaxa 5052 (2) on page 268, DOI: 10.11646/zootaxa.5052.2.6, http://zenodo.org/record/556868
Bosmina (Liederobosmina) korineki Garibian & Juračka & Kotov 2021, sp.nov.
No full textBosmina (Liederobosmina) korineki sp.nov. (Figures 1–4) Etymology. The taxon is named after Professor Vladimír Kořínek (1934–2019) (see Fott 2019), who detected this taxon in the Andean samples and send the samples to AAK for their detailed study. Type locality. Laguna Chisaca (N 4.28°, W 74.21°; 3709 m.a.s.l.), Distrito Capital de Bogotá, Colombia. Type material. Holotype. A parthenogenetic female in 96% alcohol, MGU Ml 240 in the Collection of Moscow State University, Moscow, Russia. Label of holotype: “ Bosmina korineki sp.nov., 1 parth. ♀ from Laguna Chisaca, Colombia, HOLOTYPE ”. Paratypes. 4 parthenogenetic females, MGU Ml 241. 4 parthenogenetic females, AAK 2020-017 in the personal collection of A.A. Kotov, Moscow, Russia. The type series was collected in 10.01.1990 by S. Gaviria. Other material studied. 16 females from Embalse de Neusa (N 5.16°, W 73.95°; 2967 m.a.s.l.), Cundimarca Province, Colombia, collected in 15.03.1999 by P. Alvarez in the personal collection of V. Kořínek, sent to the collection of the Natural History Museum, London, United Kingdom. Description. Parthenogenetic female. Body short and wide in lateral view in adults (Figs 1A, 2A–B, 3A) and more elongated in juveniles (Figs 1B, 3B); dorsal margin regularly curved from distalmost extremity to posterodorsal angle; posterior margin straight, its height about half of body height; ventral margin almost straight, with a shallow depression anterior to mucro. Sculpture as a strong striation on head and on valves (Fig. 2A–E, I), but not on head shield. Head without ocular dome and without a pre-ocular depression; rostrum very short, rounded. Frontal head pore small, located slightly dorsally to the level of antennae I (Fig. 3C–D: fhp). Median head pore minute (Fig. 3A, D: mhp), located posteriorly to ocular capsule. Fornix well-developed, covering coxal part of antenna II. Lateral head pore small (Figs 2E–G. 3C, E: lhp), with a raised ring-like margin, located at a great distance from ventral margin of head shield (fornix, Fig. 3C: fnx), dorsally to the level of mandibular articulation. Compound eye of moderate size. Labrum as a fleshy appendage lacking significant projections, distal labral plate small. Anterior portion of ventral valve margin with a series of stout setae. Seta kurzi with small setulae, located on internal side of valve anterior to abovementioned depression near mucro, which is strong and long even in large adults; no incisions on ventral side of mucro (Fig. 3F), while some incisions present on dorsal side of mucro in some juveniles (Fig. 3B). On inner side of mucro, there are several relatively strong denticles, as a continuation of a series of setulae at posterior valve margin. Thorax relatively long, with 6 limb pairs, abdomen short, with transverse rows of setulae (Fig. 3G). Postabdomen strongly compressed laterally, with width approximately equal along all its length, with ventral (functionally dorsal!) margin straight. Preanal margin with groups of setulae; sides of postabdomen supplied with series of finer setulae. Distal (anal) margin nearly directly truncated. Postanal portion as a cylindrical projection bearing paired postabdominal claws. Each claw regularly bent, with two pectens on concave (dorsal) margin, distal pecten consists of fine setulae, while proximal pecten consists of 7–9 rather strong, sparsely located teeth. Postabdominal seta shorter than preanal margin; its distal segment about two times shorter than proximal one, supplied with fine, long setulae. Antenna I fused with rostrum; its body relatively short; its length from tip to tip of rostrum about 0.3–0.4 body lengths (Fig. 3A–B). Antennular (frontal) sensory seta located on head surface. Free part of antenna I consists of a pre-aesthetasc portion, fused with head, and post-aesthetasc portion, presence of which is a unique synapomorphy of Bosmina (Kotov et al., 2009). Nine aesthetascs delicate, slightly differing in size. Post-aesthetasc portion directed ventrally and somewhat posteriorly, almost straight. Both portions supplied with crossing series of fine denticles. Antenna II typical for the genus (Figs 2H, 3C). Six pairs of thoracic limbs with morphology indistinguishable from that in other species (Kotov, 1995). Limb I with epipodite bearing a finger-like projection (Fig. 4A: epp). Outer distal lobe (Fig. 4A–B: odl) cylindrical, bearing a long distal seta and a long lateral seta. Subdistal lobe with a single seta of unclear homology; limb corm with six setae of unclear homology and a pair of ejector hooks (Fig. 4A–B: ejh). Distal armature of gnathobase with two setulated setae (Fig. 4A: dag). Limb II with epipodite bearing a long finger-like projection (Fig. 4C: epp). Exopodite fully reduced. Limb corm with an inner-distal lobe bearing a single anterior (1) and single posterior (a) setae; the rest of inner-distal limb portion with seven anterior (2–8) and five posterior (b–f) setae; seta 8 armed by strong denticles varying in size among specimens from same population (Fig. 4C–D). Gnathobase with distal armature of four setae (Fig. 4E–F: 1–4); seta 1 represents a sensillum. Filter plate with six setae (Fig. 4C: a–f). Limb III with epipodite having a finger-like projection (Fig. 4G: epp). Exopodite subrectangular, with five distal (1–5) and two lateral (6–7) setulated setae. Distal endite (in terms of Kotov 2013) with three anterior setae (Fig. 4G: 1–3); proximal endite with three setae (Fig. 4H: 4–6). Eight setae (a–h) on posterior limb face. Distal armature of gnathobase with four elements (Fig. 4H–I: 1–4), including a sensillum (1). Filter plates with six setae (a–f). Limb IV with ovoid densely setulated preepipodite (Fig. 4J: pep) and epipodite (Fig. 4J: epp) supplied by a finger-like projection. Exopodite (Figure 4J: ext) rounded, bearing two distal (1–2) and six lateral (3–8) setae. Inner distal portion of limb IV with four anterior setae strongly decreasing in size proximally (Figure 4K: 1–4) and four small posterior setae (a–d). Distal armature of gnathobase with four setae (Fig. 4K: 1–4). Filter plate with four setae (a–d). Limb V with densely setulated preepipodite (Fig. 4L: pep) and ovoid epipodite (epp) supplied by a long fingerlike projection. Exopodite with two distal setae (1–2) and three lateral setae (3–5). Inner limb portion as elongated, flat lobe, with setulated margin. Distal armature of gnathobase with three setae (Fig. 4L: 1–3). Limb VI represented by epipodite only (Fig. 4M: epp). Ephippial female, male. Unknown. Size. Total length (without mucro) 0.45–0.62 mm. Differential diagnosis. Our new species belongs to the subgenus B. (Liederobosmina) having: (1) lateral head pore located dorsally to the level of mandibular articulation; (2) incisions on the dorsal side of mucro in juveniles (see Lieder 1983b; Kotov et al. 2009). This taxon is unique among all the taxa of Bosmina (Liederobosmina) having heavily striated valves. Paggi (1979) recognized three species from this subgenus in South America. B. (L.) korineki sp. nov. has no elongated flattened rostrum as B. (L.) huaronensis Delachaux, and has no pre-ocular depression as B. chilense Daday. To date, we can only say that it differs from B. hagmanni Stingelin only in striated valves in the females as the males are unknown, but they possess most diagnostic characters in the bosminids (Kotov et al. 2009). Distribution. To date the taxon is known only from two large, deep high mountain lakes in Colombia. Embalse de Neusa is an artificial reservoir with surface of over 955 ha, maximum depth of 50 m and mean depth of 10 m. Secchi depth ranges from 3.6 m to 1.5 m; the lake is considered as oligo mesotrophic (Carrillo et al. 2006). We did not find in previous literature any descriptions which could be attributed to B. (L.) korineki sp.nov., although different bosminids were noted in many papers on the Neotropical fauna. Most probably, this taxon has a narrow distribution area in the Andean high mountains.Published as part of Garibian, Petr G., Juračka, Petr Jan & Kotov, Alexey A., 2021, A new species of Bosmina (Liederobosmina) Brték, 1997 (Cladocera: Bosminidae) from high mountain lakes of Colombia, pp. 280-290 in Zootaxa 4990 (2) on pages 281-287, DOI: 10.11646/zootaxa.4990.2.4, http://zenodo.org/record/502640
Figure 18 in Diversity of the subgenus Disparalona (Mixopleuroxus) Hudec, 2010 (Crustacea: Cladocera) in the New and Old World
No full textFigure 18. Disparalona (M.) cf. striatoides (Šrámek-HuŠek, 1946), parthenogenetic female from Dura River, Ethiopia. (a) Limb II; (b) limb III; (c) limb IV; (d) exopodite of limb IV; (e, f) fragments of gnathobase and filter plate of limb IV; (g) limb V. Scale bars 0.1 mm.Published as part of Neretina, Anna N., Garibian, Petr G., Sinev, Artem Y. & Kotov, Alexey A., 2018, Diversity of the subgenus Disparalona (Mixopleuroxus) Hudec, 2010 (Crustacea: Cladocera) in the New and Old World, pp. 155-205 in Journal of Natural History 52 (3-4) on page 189, DOI: 10.1080/00222933.2017.1411987, http://zenodo.org/record/517533
Pleuroxus trigonellus Garibian & Neretina & Klimovsky & Kotov 2018
No full textPleuroxus trigonellus (O.F. Müller, 1776) (Figs. 1–7) Lynceus trigonellus O.F. Müller, 1776 in Müller (1776): p. 199; Müller (1785): p. 74–75, pl. 10, figs. 5–6. Pleuroxus trigonellus (O.F. Müller) in Sars (1861): p. 124, pl. 91; Lilljeborg (1901): p. 534–537, pl. 74: figs. 13–23; Šrámek- Hušek et al. (1962): p. 376–378, fig. 141; Flössner (1972): p. 355–357, figs. 165–166; Negrea (1983): p. 240–242, fig. 96; Margaritora (1985): p. 211–213, fig. 84; Flössner (2000): p. 250–253, fig. 93; Smirnov (1966): figs. 8, 15, 16, 24, 25; Frey (1993): table 1, figs. 1–8; Røen (1995): 281–284, fig. 128; Hudec (2010): p. 421–423, fig. 104; Szeroczyńska et al. (2007): p. 63–64, figs. 322–332. Pleuroxus trigonellus trigonellus (O.F. Müller) in Smirnov (1971): p. 226, figs. 208–215. Pleuroxus ornatus Schödler, 1862 in Schödler (1862): p. 25, pl. 2: fig. 32? (no captions in the paper, fig. 38 in text, this is a mistake!); Schödler (1863): 47–48, pl. 2: fig. 32. Pleuroxus Bairdii Schödler, 1863 in Schödler (1863): p. 50–51. Type material. Lost, as whole material of O.F. Müller (Müller 1867; Frey 1980). Type locality. Denmark. The type locality was not specified, but it is known that O.F. Müller collected at least some samples in the ponds at his summer house in Frederiksdal (Frey 1980). Material examined. 10 parthenogenetic females, 3 ephippial females, 5 males from Dobrasee, Brandenburg, Germany, coll. by M. Belyaeva, AAK M-0919; 5 parthenogenetic females from Lake Glubokoe (N 55.75361°, E 36.50417°), Moscow Area, Russia, coll. 15.08.2005 by N.N. Smirnov, AAK 2006-109; 5 parthenogenetic females from the same location, coll. 16.08.2016 by A.A. Kotov, AAK M-3476; 2 parthenogenetic females from the same location, AAK M-3477; 1 parthenogenetic female from the same location, AAK M-3486; 2 parthenogenetic females from the same location, AAK M-3487; 3 parthenogenetic females from a small pond (N 55.56242°, E 39.82352°), Moscow Area, Russia, coll. 0 4.08.2014 by A.A. Zharov, AAK M-2730; 2 parthenogenetic females from the same location, AAK M-2731; 2 parthenogenetic females from Sen’ga River (N 55.8839°, E 39.52012°), Vladimir Area, Russia, coll. 0 6.08.2014 by A.A. Zharov, AAK M-2740; 5 parthenogenetic females from a small pond 50 m from the shore of Chudskoe Lake, near the village Zapol'je (N 58.63642°, E 27.78997°), Pskov Area, Russia, coll. 19.08.2007 by A.A. Kotov, AAK M-0596; 2 parthenogenetic females from a small lake ffi 1 in the vicinity of Penza, Sosonivka, (N 53.1739°, E 45.0767°), Penza Area, Russia, coll. in May of 2009 by E.I. Bekker, AAK M-0934; 2 parthenogenetic females from a small lake ffi 2 in the vicinity of Penza (N 53.212°, E 45.088°), Penza Area, Russia, coll. 0 5.05.2010 by E.I. Bekker, AAK M-1807; 2 parthenogenetic females from Cherepovets Reservoir, Vologda Area, Russia, coll. 17.07.1966 by N.N. Smirnov, NNS 1998-183; 3 parthenogenetic females from Gor’kovskoe Reservoir (N 56.8°, E 43.3°), Nizhny Novgorod Area, Russia, coll. 28.08.1961 by N.N. Smirnov, NNS 1999-056. Diagnosis (adapted after Frey 1993). Body transparent. Parthenogenetic and ephippial female with length up to 0.60 mm. Median dorsal keel absent. Sculpture of valves and head moderately or strongly developed. Rostrum sharply pointed, directed downwards. Labral keel short (not projected behind tip of rostrum), triangular, its anterior margin slightly convex, distal angle acute. Posteroventral angle of valve with few denticles. Postabdomen moderately elongated, tapered distally, postanal margin almost straight, with strong postanal teeth, on postabdominal claw proximal basal less than half size of distal one. Antenna I in female elongated, with a basal peg and nine aesthetascs of unequal size. Apical swimming setae of antenna II subequal in size. Filter plate of gnathobase II with eight setae; filter plate III with 8 setae; filter plate IV with 6 setae; filter plate V with 4 setae. Male with length up to 0.45 mm. Rostrum shorter as compared to the female. Distal portion of the postabdomen shaped as a tube lacking setules, postanal teeth transformed into bunches of long, thin setules. Gonopore opens ventrally at level of postabdomen narrowing (base of the tube). Antenna I in male without a basal peg and with nine aesthetascs of unequal size. Redescription. Parthenogenetic female. General. Body transparent. In lateral view body subovoid, high (body height/ body length = 0.71–0.73 in adults). Maximum height in middle of body (Figs. 1 A–B, 2A–B). In dorsal and anterior view body compressed laterally, lacking a median dorsal keel (Figs. 1C, 2 C–F). Dorsal margin evenly arched from tip of rostrum to posterodorsal angle, without a depression between head and the rest of body. Posterior margin relatively straight, posteroventral angle almost straight, with teeth, ventral margin with a slight prominence in thirst half of body behind head (Figs. 1 A–B, 2A–B), with a row of marginal setae (Figs. 1 A–B, 2A, 4C–E). Obscure striation as hexagons on all body surface (Figs. 1A, 2A, 4 A–B). Head with a long, pointed rostrum, protruding downward and posteriorly (Figs. 1 D–E, 2A–F, 4A–B, F). Eye only slightly larger than ocellus, distance from tip of rostrum to ocellus greater than that between ocellus and eye (Figs. 1 A–B, 1E). Head shield elongated, with maximum width immediately behind mandibular articulation (Figs. 1D, 1F, 2F, 4 G–H). In dorsal view rostrum elongated, with acute apex (Figs. 1D, 2 C–F). Two major head pores (Figs. 1 F–G, 4G–H), PP = 1.6 IP. Lateral head pores minute, located at the headshield midline between major pores (Fig. 1G), usually these are positioned somewhat asymmetrically to the midline. Labrum with a fleshy main body and a small distal labral plate (Fig. 1E). Labral keel short (not projected behind rostrum tip), triangular, its anterior margin slightly convex, distal angle acute. Valves large, ventral margin armed with numerous setae of different size in different regions, all plumose and located exactly marginally (Figs. 1 A–B, 2A–B, 3C–E, 4B–E). Posterior margin of valves with few (1–3, mainly 2) teeth (Figs. 1 A–B, 2A–B, 3D–E, 4D–E). Ventral margin bears setae covered by long prominent setules (Fig. 3 C–E, 4C–D). Anterior valve margin broadly rounded (Fig. 3A, 4 A–B). Postabdomen elongated, subrectangular, its ventral margin almost straight (Figs. 3 F–I, 6A–B). Basis of postabdominal setae surrounded by a prominent chitin ring (Fig. 3H, 6D). Preanal margin slightly concave (Figs. 3 F–H, 6A–C), and slightly longer than anal margin, preanal and postanal angle well-defined, postanal margin clearly longer than anal margin, dorsodistal angle almost right (Figs. 3I, 6 E–G). Basis of claws inflated (Figs. 3 H– I, 6E–F). Each side of the postanal portion with a row of long and thickened postanal teeth, increasing in size distally (Fig. 3I, 6G). Laterally to marginal denticles, a row of fascicles consisting of bunches of short, fine setules (Figs. 3 H–I). Postabdominal seta longer than postanal margin, with basal segment approximately as long as preanal margin and distal segment shorter than basal one, implanted with delicate setules (Fig. 3G). Postabdominal claw massive and long (subequal in length to anal and preanal margins), slightly curved (Figs. 3I, 6 E–G). Dorsal edge of claw armed with a row of fine setules decreasing in size distally (Fig. 6G). Two basal spines, distalmost basal spine long (slightly longer than the base of claw), proximalmost basal spine relatively short, two times shorter than distal spine (Figs. 3 H–I, 6E–F). Antenna I not reaching tip of rostrum, narrowing distally, with a well-defined basal peg (Figs. 3 J–K). Antennular sensory seta slender, longer than half of antenna I, arising at half of antennular body. Nine short aesthetascs unequal in length (Figs. 3 J–K). Antenna II relatively short, coxal part with two sensory setae, basal segment robust, with a small spine (Figs. 1 A–B, 3L, 4F). Antennal branches elongated, exopod and endopod subequal in length, all segments cylindrical, covered by transverse rows of fine spinules (Fig. 4F). Antennal formula: setae 0-0-3/1-1-3, spines 1-0-1/0-0-1. Proximal segment of exopod with a short spine. Exopod and endopod apical swimming setae, as well as lateral endopod setae covered by fine long setules; distal segments of apical setae with chitin insertions (Figs. 3 L–M). Apical spines of exopod and endopod subequal in size (Fig. 4F). Limb I (Figs. 5 A–B, 6H): accessory seta, or corm seta in Frey (1993a), present (not represented in Fig. 5A, because it is located on the other side of the limb corm), ODL relatively small, bears a long seta with a naked distal segment, and a short seta with short, setulated distal segment (Figs. 5 A–B). IDL larger than ODL, covered by transverse rows of setules (Fig. 6H). First IDL seta short, naked, second and third IDL setae not equal in size and similarly armed distally with short, fine setules (Figs. 5 A–B). Endite 3 with three soft posterior setae (a–c) and stiff anterior seta 1 of similar length. Endite 2 with short seta anterior (seta d), long (setae e and f), and delicate posterior seta 2 armed with minute setules. Endite 1 with long, slender posterior setae (g–i), a very short seta (j), and anterior seta 3 (it significantly shorter than seta 2). Fascicles of thin setules on inner face of limb, plus bunches of longer thicker setules at ventral margin of limb. Two slender ejector hooks of remarkably different size. A short seta, a remnant of maxillar process, on limb base. Limb II (Fig. 5C) subrectangular. Exopodite subquadrangular, with a short seta. Inner portion of limb with eight setae: setae 1–3 especially long, setae 4–5 shorter, subequal in size, setae 6–8 short, also subequal in size. A series of small projections posteriorly to distal setae, and a small sensillum near scraper 4. Distal armature of gnathobase with a bunch of plumose setules, unique for the anomopods, and four setae. Filter plate with eight setae, two distalmost setae subequal in size and shorter than the rest; basal most seta of filter plate with inflated basal segment. Limb III (Figs. 5 D–E) with ovoid elongated epipodite. Exopodite subrectangular, with four distal setae (1–4), and three lateral setae (5–7). Distal endite with three anterior setae (Figs. 5 D–E), all with minute setules distally, of them two distal setae (1–2) long, basalmost seta (3) short. Small sensillae near bases of setae 2 and 3. Basal endite with four anterior setae (4–7), slightly increasing in size basally, not armed, small bottle-shaped sensillum near seta 4. On the posterior surface, six soft setae (a–f) subequal in length, bilaterally armed with sparse, fine setules. Gnathobase not clearly separated from basal endite. Distal armature of gnathobase with large, bottle-shaped sensillum, three setae, and a bunch of setules. Filter plate with eight setae. Limb IV (Figs. 5 F–G) with ovoid elongated epipodite and rounded preepipodite. Exopodite wide, subovoid, with seven setae of unequal size. Innerdistal portion of limb IV with four marginal setae. Distalmost seta (1) slender and uncovered with minute setules on distal segment, setae 2–4 with thick basal segments and slender, setulated distal segments. On posterior surface, four soft setae (a–d). Gnathobase well-separated, its distal armature with four setae. Filter plate with six setae. Limb V (Fig. 5H) with ovoid elongated epipodite and rounded preepipodite. Exopodite large, subovoid, with a single distal seta 1 and three lateral setae (2–4), distally to seta 1 there are two projections bearing long setules. Inner limb portion as truncated, flat lobe, with setulated inner margin, supplied with setulated setae 1 and 2, the latter bears specially robust setules. Distal armature of gnathobase as a single projection. Filter plate with four long setae. Ephippial female. Identical to parthenogenetic female in size and shape, but anterodorsal portion of valves modified into an ephippium. The ephippium is not bordered from the rest of body, brownish, contains a single resting egg. Adult male. General. Body transparent. In lateral view body elongated (height/length ratio about 0.69 in adults) (Fig. 7A). Dorsal margin slightly convex, posterodorsal angle expressed, posteroventral angle broadly rounded. Ventral margin strongly convex. Head relatively small, narrow. Rostrum relatively short, pointed, only a little bit longer than antenna I (Fig. 7A). Compound eye slightly larger than ocellus. Distance from tip of rostrum to centre of ocellus somewhat larger than distance between centers of ocellus and eye. Labrum with a relatively short, triangular labral keel, similar in proportion to that in female (Fig. 7B). Armature of anteroventral angle of valve similar to female (Fig. 7C). Postabdomen elongated, tapering distally (Fig. 7D). Postabdomen length/height ratio about 2.8. Ventral margin broadly concave, somewhat undulated in postanal portion. Preanal and anal margins slightly concave. Postanal margin broadly convex. Postanal margin about 2 times longer than anal and preanal margins. Postanal and preanal angles smooth. Postanal margin armed by bunches of long setules of similar size through all the margin length, following by clusters of short setules on anal margin. Bunches of fine setules on lateral surfaces of postanal and anal margins. Distal portion of postabdomen as a tube, no setules on it. Gonopores open ventrally on the level of postabdominal narrowing. Some short spinules near them. Postabdominal claw almost straight, 2 times shorter than anal margin, with a thin basal spine subequal in length to claw diameter at base, and a tiny second basal spine (Fig. 7D). Antenna I conically narrowing, short (thicker than in female), without a basal peg, with nine terminal aesthetascs of different size. Male seta long, arising at the middle of antenna I, slightly shorter than antennular sensory seta (Fig. 7E). Antenna II similar to female (Fig. 7F). Limb I with a U-shaped copulatory hook (Fig. 7G). Inner distal lobe carries four setae (one of them especially long, three setae shorter). Male seta slender, slightly curved. Size. Maximum length of adult parthenogenetic females up to 0.60 mm, maximum height 0.45 mm. Maximum length and height of ephippial females subequal to adult parthenogenetic females. Maximum length of adult males up to 0.45 mm, height 0.30 mm. Variability. No significant variability between investigated individuals was found. Some variability was found in armature of posteroventral angle of valve and concerns both the number of denticles and their shape. Distribution. In the course of our investigation, adult males were found only in a sole population from Germany (relatively close to terra typica in Denmark). We assume that typical Pleuroxus trigonellus is widely distributed in North and Central Europe and in the European part of Russia. Confirmation of this fact could be found in previous literature (keeping in mind differences between two species only in male characters: basal peg on antenna I and distal portion of postabdomen). Our analysis of previous literature suggests that P. trigonellus s.str. is common in Denmark (Frey 1993, see male antenna I in fig. 10; male postabdomen in fig. 8), present in Norway (Sars 1861, see male postabdomen in fig. 91(7)), Germany (Flössner 1972, see male postabdomen in fig. 165D; Flössner 2000, male antenna I in fig. 93I; male postabdomen in fig. 93K), Italy (Margaritora 1985, see male antenna I in fig. 84c; male postabdomen in fig. 84E), Czech Republic (Šrámek-Hušek et al. 1962, see male antenna I in fig. 141e; male postabdomen in fig. 141f), Slovakia (Hudec 2010, see male antenna I in fig. 104M; male postabdomen in fig. 104L), Poland (Szeroczyńska et al. 2007, see male postabdomen in fig. 323), Romania (Negrea 1983, male postabdomen, see fig. 96H), it is common in different regions of European Russia (Smirnov 1966, male antenna I and postabdomen, see fig. 16; Smirnov 1971, male antenna I and postabdomen, see fig. 213). At least similar, if not conspecific, forms are present in Greenland (Røen 1995, see male postabdomen in fig. 128c). According to Smirnov (1971), P. ornatus Schödler, 1862, P. Bairdii Schödler, 1863 and Pleuroxus trigonellus var. Entzi Kottász, 1913 are junior synonyms of P. trigonellus. In reality, the latter was established as a nomen nudum, and could not be discussed. Most probably, former two taxa are junior synonyms of P. trigonellus, e.g. taking into consideration that we found only a single taxon from this group in Europe.Published as part of Garibian, Petr G., Neretina, Anna N., Klimovsky, Alexey I. & Kotov, Alexey A., 2018, A new case of West-East differentiation of the freshwater fauna in Northern Eurasia: the Pleuroxus trigonellus species group (Crustacea: Cladocera: Chydoridae), pp. 451-482 in Zootaxa 4532 (4) on pages 453-463, DOI: 10.11646/zootaxa.4532.4.1, http://zenodo.org/record/261552
