Research Article |
Corresponding author: Adrian Smolis ( adek@biol.uni.wroc.pl ) Academic editor: Louis Deharveng
© 2018 Adrian Smolis, Nataliya Kuznetsova.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Smolis A, Kuznetsova N (2018) Paravietnura gen. n., a new intriguing genus of Neanurini from the Caucasus (Collembola, Neanuridae, Neanurinae). ZooKeys 739: 41-54. https://doi.org/10.3897/zookeys.739.22041
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Paravietnura gen. n. is described and established for two new species of Neanurini from the Caucasus. The new genus is characterized by an unusual combination of features: the fusion of all lateral tubercles on the head into a single mass, the strong reduction of chaetae on the head, the fusion of cephalic tubercles Af and Oc into a transverse band, the absence of labial chaetae f, the presence of microchaetae on furca rudimentary, and the penultimate abdominal tergum with two tubercles separated along the midline. Paravietnura gen. n. strongly resembles Vietnura Deharveng & Bedos, 2000, a monotypic genus up to date known only from Vietnam. The main characteristics of Paravietnura notabilis sp. n. include an ogival labrum, the absence of chaetae A on the head, relatively thick and widely sheathed long macrochaetae, and minute microchaetae without chaetopores on furca rudimentary. Paravietnura insolita sp. n. differs from the previous species in chaetotaxic details, the size of furcal microchaetae, and the shape of the labrum. Short comments on the generic diversity of the tribe in the Western Palaearctic are also provided.
Paravietnura notabilis sp. n., Paravietnura insolita sp. n., Russia, springtails, taxonomy
The subfamily Neanurinae, with more than 800 recognized species, is certainly one of the richest and most diversified taxa among springtails (Collembola). It is also one of the most recognizable ones within Collembola as its members possess very characteristic cuticular tubercles on the dorsal side of the body and completely lack the furca, the organ typical for most described springtails. Regarding the taxonomy of Neanurinae, all species are classified into six established tribes (
The examination of rich Neanurinae materials from the north-western Caucasus has revealed two unknown species. They belong to the mentioned tribe because of a presence of blue hypodermic pigment, the last abdominal segment bilobed and well developed tubercles on the body. Interestingly, both the undescribed taxa are characterized by the complete fusion of the outlined cuticular structures on the lateral part of head. This and other features of these species support proposal of a new genus within the tribe. Its detailed and illustrated description is provided with comments on the present stage of knowledge on Neanurini diversity in the Western Palaearctic region.
Terminology for the description follows that of
General morphology:
Abd. abdomen,
Ant. antenna,
AOIII sensory organ of antennal segment III,
Cx coxa,
Fe femur,
Scx2 subcoxa 2,
T tibiotarsus,
Th. thorax,
Tr trochanter,
VT ventral tube.
Groups of chaetae on body excluding antennae:
Ag antegenital,
An chaetae of anal lobes,
Fu furcal,
Ve ventroexternal,
Vea ventroexternoanterior,
Vem ventroexternomedial,
Vep ventroexteroposterior,
Vel ventroexternolateral,
Vec ventroexternocentral,
Vei ventroexternointernal,
Vi ventrointernal,
Vl ventrolateral.
Groups of chaetae on antennae:
ap apical,
ca centroapical,
cm centromedial,
cp centroposterior,
d dorsal,
vc ventrocentral,
ve ventroexternal,
vi ventrointernal.
Tubercles:
Af antenno–frontal,
Cl clypeal,
De dorsoexternal,
Di dorsointernal,
Dl dorsolateral,
L lateral,
Oc ocular,
So subocular.
Types of chaetae:
Ml long macrochaeta,
Mc short macrochaeta,
Mcc very short macrochaeta,
me mesochaeta,
mi microchaeta,
ms ,
S or s chaeta s,
bs s–chaeta on Ant. IV,
miA microchaetae on Ant. IV,
iv ordinary chaetae on ventral Ant. IV,
or organite of Ant IV,
brs border s–chaeta on Ant. IV,
i ordinary chaeta on Ant. IV,
mou cylindrical s–chaetae on Ant. IV (“soies mousses”),
x labial papilla x,
L’ ordinary lateral chaeta on Abd. V,
B4, B5 ordinary chaetae on tibiotarsi,
sgv s–chaeta on Ant. III.
The specimens were cleared in Nesbitt’s fluid, subsequently mounted on slides in Phoera liquid and studied using a Nikon Eclipse E600 phase contrast microscope. Figures were drawn with camera lucida and prepared for publication using Adobe Photoshop CS3.
DIBEC Department of Invertebrate Biology, Evolution and Conservation, Institute of Environmental Biology, University of Wrocław, Poland.
MSPU Moscow State Pedagogical University, Institute of Biology and Chemistry, Moscow, Russia.
Paravietnura notabilis sp. n. (here designated).
Blue pigment present on the body. Tubercles on body well developed, free chaetae on abdomen absent. Two pigmented eyes on each side of head. Mouth parts reduced, maxilla styliform, mandible thin and tridentate. Six tubercles on head, with Dl fused to (L + So), Af fused to Oc, and Di fused to De. Chaetotaxy of head strongly reduced, with chaetae C, D, E, Oca, Di2 and De2 absent. Labrum with four or two prelabral chaetae. Labial chaetae f absent. Tubercles (Di+De+Dl) on Abd. V separate along midline. Cryptopygy present as Abd. VI poorly visible from dorsal side. Claw untoothed.
The name “Paravietnura” refers to its strong similarity to Vietnura.
The following characters: the presence of 2+2 eyes, the fusion of all lateral tubercles into a single mass on the head, the fusion of cephalic tubercles Af and Oc into a transverse band, the absence of cephalic chaetae Di2 and De2 and the presence of strong cryptopygy place Paravietnura gen. n. very close to Vietnura, the genus established by
Because of the fusion of lateral tubercles on head, Paravietnura gen. n. resembles Monobella cassagnaui Deharveng, 1981, the species belonging to the European genus Monobella Cassagnau, 1979. Nevertheless, this similarity seems to be definitely superficial given the fact that M. cassagnaui differs from Paravietnura gen. n. in a number of characters e.g.: fusion of tubercles (Di+De) on head along midline (separate in Paravietnura gen. n.), presence of chaetae Di2 and De2 on head (absent in Paravietnura gen. n.), fusion of tubercles Di and De on Th. II–III and Abd. I–II (separate in Paravietnura gen. n.), fusion of tubercles Di on Abd. III along midline (separate in Paravietnura gen. n.) and presence of one tubercle (2Di+2De+2Dl) on Abd. V (two tubercles (Di+De+Dl) in Paravietnura gen. n.).
Holotype: female on slide, Russia, NW Caucasus, Adygeya, Caucasus Nature Reserve, Lagonaki Plateau (‘Kamennoye More’ ridge), 1843 m.alt., litter of rocky pine forest with birch, N44.06159° E40.02103°, 03.07.2014, leg. M. Potapov, N. Kuznetsova, A. Kremenitsa 2014, leg. (MSPU). Paratype: juvenile on slide, ibid., southern slope, 1847 m alt., mixed forest (pine, birch), coniferous litter, N44.06096° E40.02112°, 21.07.2015, leg. M. Potapov, N. Kuznetsova, A. Kremenitsa, L.Vanyavina (DIBEC).
The name reflects the notable morphology of this new generotype species.
Body stumpy and relatively short. Macrochaetae long, thick and widely sheathed. Buccal cone long, labrum ogival. Labrum with two prelabral chaetae. Tubercle (Af +2Oc) on head with chaetae B, Ocm and Ocp, chaetae A absent. Tubercles (Dl+L+So) on head with ten chaetae, chaetae So2 absent. Furca rudimentary with minute and difficult to detect microchaetae, without chaetopores.
General. Body length (without antennae): 0.55 (juvenile) to 0.85 mm (holotype). Colour of the body bluish. 2+2 black eyes of medium size (Fig.
Chaetal morphology. Dorsal ordinary chaetae of four types: long macrochaetae (Ml), short macrochaetae (Mc), very short macrochaetae (Mcc) and mesochaetae. Long macrochaetae of large length (distinctly longer than length of segment), thick, slightly arc-like or straight, widely sheathed, strongly serrated and apically rounded (Figs
Antennae. Dorsal chaetotaxy of Ant. III–IV as Fig.
Mouthparts. Buccal cone particularly long with labral sclerifications ogival (Fig.
Dorsal chaetotaxy and tubercles. Chaetotaxy of head as Fig.
Ventral chaetotaxy. On head, groups Vea, Vem and Vep with 3, 2, 4 chaetae respectively. Group Vi on head with six chaetae. On Abd. IV, furca rudimentary with minute microchaetae (Fig.
Legs. Chaetotaxy of legs as in Table
Tubercle | Number of chaetae | Types of chaetae | Names of chaetae |
---|---|---|---|
Cl | 4 | Ml | F |
Mc | G | ||
(Af+2Oc) | 6 | Ml | B, Ocm |
Mc | Ocp | ||
(Di+De) | 2 | Ml | Di1, De1 |
(Dl+L+So) | 10 | Ml | Dl1, Dl5, L1, So1 |
Mc | L4 | ||
Mcc | Dl4 | ||
me | So3–6 |
Segment, Group | Number of chaetae | Segment, Group | Number of chaetae adult |
---|---|---|---|
I | 7 | IV | or, 8 S, i, 12 mou, 6 brs, 2 iv |
II | 11 | ||
IIIve | 5 sensilla AO III | ||
5 | ap | 8 bs, 5 miA | |
vc | 4 | ca | 2 bs, 3 miA |
vi | 4 | cm | 3 bs, 1 miA |
d | 4 | cp | 8 miA, 1 brs |
Terga | Legs | ||||||||
---|---|---|---|---|---|---|---|---|---|
Di | De | Dl | L | Scx2 | Cx | Tr | Fe | T | |
Th. I | 1 | 2 | 1 | - | 0 | 3 | 6 | 13 | 19 |
Th. II | 3 | 2+s | 3+s+ms | 3 | 2 | 7 | 6 | 12 | 19 |
Th. III | 3 | 3+s | 3+s | 3 | 2 | 8 | 6 | 11 | 18 |
Sterna | |||||||||
Abd. I | 2 | 3+s | 2 | 3 | VT: 4 | ||||
Abd. II | 2 | 3+s | 2 | 3 | Ve: 4; chaeta Ve1 absent | ||||
Abd. III | 2 | 3+s | 2 | 3 | Vel:4; Fu: 5 me, 4 mi | ||||
Abd. IV | 2 | 2+s | 3 | 5 | Vel: 4; Vec: 2; Vei: 2; Vl: 4 | ||||
Abd. V | 6–7+s | Ag: 3; Vl: 1 | |||||||
Abd. VI | 7 | Ve: 9–10; An: 2mi |
See Remarks of Paravietnura insolita sp. n.
The new species seems to be very local and connected with specific climatic or vegetation conditions (rocky pine-birch forest, Fig.
Holotype: male on slide, Russia, Caucasus, Northern Ossetia, North Ossetia Nature Reserve, surroundings of the village Tsey, Kalpersky ridge, southern slope, 2160 m alt., litter of rocky pine grass forest, 19.8.1977, leg. M. Rudakovsky, N. Kuznetsova (MSPU). Paratype: male on slide, ibid., green moss pine forest, in mosses, 23.9.1980, leg. I. Kuchiev (DIBEC).
Its name reflects a later discovery of another species within the genus (Latin word “insolita” means not lonely).
Body relatively short and squarish. Macrochaetae long, relatively thin and narrowly sheathed. Buccal cone rather short, labrum non ogival. Labrum with four prelabral chaetae. Tubercle (Af +2Oc) on head with chaetae A, B, Ocm and Ocp. Tubercles (Dl+L+So) on head with eleven chaetae, chaetae So2 present. Furca rudimentary with well visible microchaetae, with chaetopores.
General. Body length (without antennae): 1.10 (paratype) to 1.35 mm (holotype). Colour of the body bluish. 2+2 black eyes of medium size (Fig.
Paravietnura insolita sp. n.: 9 dorsal chaetotaxy of head and Th. I (holotype) 10 dorsal chaetotaxy of Ant. III–IV 11 ventral chaetotaxy of Ant. III 12 dorsal chaetotaxy of Abd. V–VI 13 furca rudimentary 14 chaeta Di1 of Abd. IV 15 chaeta Di1 of Abd. V 16 sensillum of Abd. V 17 labrum 18 labium. Paravietnura notabilis sp. n.: 19 labium 20 labrum. Vietnura caerulea Deharveng and Bedos, 2000: 21 labium.
Chaetal morphology. Dorsal ordinary chaetae of four types: long macrochaetae (Ml), short macrochaetae (Mc), very short macrochaetae (Mcc) and mesochaetae. Long macrochaetae of medium length (longer than length of segment), relatively thin, slightly arc-like or straight, narrowly sheathed, strongly serrated and apically rounded (Figs
Antennae. Dorsal chaetotaxy of Ant. III–IV as Fig.
Mouthparts. Buccal cone short with labral sclerifications non-ogival (Fig.
Dorsal chaetotaxy and tubercles. Chaetotaxy of head as Fig.
Ventral chaetotaxy. On head, groups Vea, Vem and Vep with 3, 2, 4 chaetae respectively. Group Vi on head with six chaetae. On Abd. IV, furca rudimentary with clearly visible microchaetae, each with chaetopore (Fig.
Legs. Chaetotaxy of legs as in Table
Paravietnura insolita sp. n. can be confused with the only other described species in the genus Paravietnura notabilis sp. n., which has thick and widely sheathed long macrochaetae (distinctly thinner and narrowly sheathed in insolita), an ogival labrum (non-ogival in insolita), chaetae A and So2 reduced on the head (present in insolita), chaetae L’ reduced on Abd. V (present in insolita), and the furca rudimentary with minute microchaetae without chaetopores (longer microchaetae with distinct chaetopores in insolita).
Similarly to the previous species, Paravietnura insolita sp. n. seems to be very local and connected with specific climatic and vegetation conditions, probably with mountain xeric pine forest.
We observed an asymmetrical absence of chaeta A in the holotype (Fig.
Tubercle | Number of chaetae | Types of chaetae | Names of chaetae |
---|---|---|---|
Cl | 4 | MlMc | FG |
(Af+2Oc) | 8 | MlMc | B, OcmA, Ocp |
(Di+De) | 2 | Ml | Di1, De1 |
(Dl+L+So) | 11 | MlMcMccme | Dl, Dl5, L1, So1L4Dl4, So2So3–6 |
Segment, Group | Number of chaetae | Segment, Group | Number of chaetae adult |
---|---|---|---|
I | 7 | IVap | or, 8 S, i, 12 mou, 6 brs, 2 iv |
II | 11 | ||
IIIve | 5 sensilla AO III | ||
5 | 8 bs, 5 miA | ||
vc | 4 | ca | 2 bs, 3 miA |
vi | 4 | cm | 3 bs, 1 miA |
d | 4 | cp | 8 miA, 1 brs |
Terga | Legs | ||||||||
---|---|---|---|---|---|---|---|---|---|
Di | De | Dl | L | Scx2 | Cx | Tr | Fe | T | |
Th. I | 1 | 2 | 1 | - | 0 | 3 | 6 | 13 | 19 |
Th. II | 3 | 2+s | 3+s+ms | 3 | 2 | 7 | 6 | 12 | 19 |
Th. III | 3 | 3+s | 3+s | 3 | 2 | 8 | 6 | 11 | 18 |
Sterna | |||||||||
Abd. I | 2 | 3+s | 2 | 3 | VT: 4 | ||||
Abd. II | 2 | 3+s | 2 | 3 | Ve: 5; chaeta Ve1 present | ||||
Abd. III | 2 | 3+s | 2 | 3 | Vel: 4; Fu: 5–6 me, 8 mi | ||||
Abd. IV | 2 | 2+s | 3 | 5 | Vel: 4; Vec: 2; Vei: 2; Vl: 4 | ||||
Abd. V | 6+s | Ag: 2; Vl: 1, L‘: 1 | |||||||
Abd. VI | 7 | Ve: 11–12; An: 2mi |
As noted in the Introduction, the tribe Neanurini, containing more than 170 species in 23 genera, is the second largest within the subfamily Neanurinae. Paradoxically, in spite of such a large number of known species belonging to the tribe, knowledge about its distribution and diversity seems to be still incomplete and far from satisfactory. For example, the largest generic and species diversity of Neanurini occurs in the Western Palaearctic, where currently 18 genera and nearly 150 species are known. It should be mentioned that the tribe in this region absolutely dominates and constitutes more than 80% of all genera and species of Neanurinae. The other four Neanurinae tribes are represented only by single native species (Paranurini, Sensillanurini), single introduced species (Lobellini), and a few genera with relatively small numbers of species (Paleonurini). However, presently the picture of the generic distribution of Neanurini is highly uneven as its seven genera are known exclusively from Europe (Albanura Deharveng, 1982; Cansilianura Dallai & Fanciulli, 1983; Catalanura Deharveng, 1983; Lathriopyga Caroli, 1910; Monobella Cassagnau, 1979; Neanurella Cassagnau, 1968; Pumilinura Cassagnau, 1979), and the next seven taxa (Balkanura Cassagnau, 1979, Cryptonura Cassagnau, 1979; Deutonura Cassagnau, 1979; Endonura Cassagnau, 1979; Neanura MacGillivray, 1893; Protanura Börner, 1906; Thaumanura Börner, 1932) are present both in Europe and in areas around it, e.g., Asia Minor, the Middle East, the Caucasus, or North Africa. That means that as many as 14 genera of the tribe, of 18 known in the western part of the Palaearctic, are present in Europe. Fortunately, to better understand the distributional pattern of Neanurini, a substantial number of studies dedicated to poorly investigated areas outside the continent have been undertaken during the last three decades. They have resulted the descriptions of four unknown genera, i.e. Caucasanura Kuznetsova & Potapov, 1988; Edoughnura Deharveng, Hamra-Kroua & Bedos, 2007; Ghirkanura Kuznetsova & Potapov, 1988; Persanura Mayvan, Shayanmehr, Smolis & Skarżyński, 2015; and many new species and records of known taxa (e.g.,
The work was financially supported by the Russian Foundation for Basic Research (grant 04-16-01228) and the Institute of Environmental Biology, Faculty of Biological Science, University of Wrocław, Poland (project no. 1076/Ś/IBŚ/2017). We are grateful to Prof. Pietro Paolo Fanciulli and Prof. Gang Jiang who reviewed the manuscript. We are also much indebted to the Editor Prof. Louis Deharveng for helpful remarks.