Research Article |
Corresponding author: Pavel S. Nefediev ( p.nefediev@mail.ru ) Academic editor: Marzio Zapparoli
© 2017 Gyulli Sh. Farzalieva, Pavel S. Nefediev, Ivan H. Tuf.
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:
Farzalieva GSh, Nefediev PS, Tuf IH (2017) Lithobius (Chinobius) yuchernovi, a new lithobiid species from northeastern Siberia and the Kamchatka Peninsula, Russia (Chilopoda, Lithobiomorpha). ZooKeys 693: 95-108. https://doi.org/10.3897/zookeys.693.14769
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Lithobius yuchernovi sp. n. is described, based on type material from the Ola Plateau, Magadan Region, Russia. The new species is widely distributed in northeastern Siberia, ranging from the Magadan Region, until the eastern Chukot Autonomous Region and the Kamchatka Peninsula in the southeast, whence non-type material is documented. This species belongs to the subgenus Chinobius Matic, 1973 based on the structure of the female gonopodal claw (more than two denticles on the internal ridge). It differs from all Palearctic species of the genus Lithobius by the following apomorphy: distoventral tubercle supporting a cluster of long and curved setae situated on the last male tibia. In addition, it shows dorsal and ventral sulci on the last legs. New replacement names are introduced: Lithobius zachiui nom. n. for Lithobius (Chinobius) orientalis (Matic, 1973) and Lithobius carli nom. n. for Lithobius (Alokobius) orientalis Attems, 1953.
Lithobius , new species, nomina nova, Russian Far East, Siberia, taxonomy
Northeastern Siberia, Russia, is a large territory lying east of the Lena and Aldan rivers and extending until the Bering Strait and the shores of the Bering Sea, between the Arctic and Pacific oceans. The Kamchatka Peninsula borders northeastern Siberia from the south and belongs to the Kamchatka-Kurilian geographical province (
The lithobiomorph fauna of both regions is still poorly studied. To date, northeastern Siberia and the Kamchatka Peninsula are known to support only four species of one genus (
The present paper provides a description of the new species, with short comments on the taxonomic problems encountered in the subgenus Chinobius Matic, 1973 it belongs to. Additionally, new replacement names are introduced for junior homonyms.
Fifty-four specimens of both sexes of the new species treated below were collected from the Ola Plateau highlands, Magadan Region, by O.L. Makarova and A.B. Babenko. The type locality of the new species (Ola Plateau) is situated 130 km inland from the Sea of Okhotsk coast, northwest of the city of Magadan. It occupies an area of about 100 km2 (
Additional non-type material (139 specimens) was collected from several localities in the Magadan Region, the Chukot Autonomous Region, and the Kamchatka Peninsula.
Material is currently deposited in the collections of the Zoological Museum of the Lomonosov Moscow State University, Moscow, Russia (
The terminology of the external anatomy follows
Measurements. The total body length was measured from the fore margin of the cephalic plate to the posterior end of the postpedal tergite. Leg length was measured excluding the length of the claw. Lengths are given as the minimum and maximum values. All measurements are given in millimeters (mm).
Plectrotaxy. Legs spinulation data are given in a separate table for holotype only. The number of coxal pores on legs 12–15 is presented in a formula where a sequence of Arabic numerals means the number of pores on these legs, respectively.
SEM micrographs were prepared at the
V ventral
D dorsal
T, TT tergite, tergites
S sternite
C coxa
t trochanter
P prefemur
F femur
Ti tibia
Ts1 tarsus 1
Ts2 tarsus 2
a anterior
m median
p posterior
Holotype ♂ (
Paratypes: 3 ♂♂, 4 ♀♀ (
Non-type material: Chukot Autonomous Region: 6 ♂♂, 5 ♀♀, 1 subadult ♀ (
The new species honours Academician Yury Ivanovich Chernov (1934–2012), the outstanding researcher of the Arctic (
A species of the genus Lithobius Leach, 1814, subgenus Chinobius Matic, 1973, normally with 20+20 elongate antennal articles; 9–11 ocelli, arranged in three rows; Tömösváry’s organ similar in size to the nearest ocellus; 2+2 teeth and setiform porodonts at dental margin of coxosternite; tergites without processes at posterior angles; tarsi 2-segmented, articulation being well-defined on all legs; legs 14–15 with DCa, leg 15 with an accessory apical claw; female gonopods with 2+2 spurs, gonopodal claw with 2–3 poorly-expressed denticles on internal ridge and with a single well-defined denticle on external ridge; last pair of legs swollen in male, ventrodistally with a group of curved setae on a round tubercle on tibiae, as well as shallow dorsal and ventral sulci on femora and tibiae.
(Figure
Holotype ♂. Body 12.9 mm long; colour in alcohol yellow-brownish, with a distinct, darker, axial stripe on forcipular T–T 10, thereafter axial stripe poorly-expressed. Tergites: almost smooth, without visible setae, T 15 distinct; posterior angles rounded from forcipular T to T 9; posterior margin of TT 10, 12 and 14 slightly sinuate; TT 9, 11, 13 and 15 without triangular projections, but TT 13 and 15 with posterior angles slightly drawn back (Fig.
Lithobius (Chinobius) yuchernovi sp. n., paratypes. 1 male 8–16 tergites, dorsal view 2 male front body part, dorsal view 3 female coxal pores of legs 12–15, ventral view 4 male forcipular coxosternite, ventral view 5–6 female gonopod, ventral and dorsal view, respectively 7 male gonopod, ventral view 8 female ocelli and Tömösváry’s organ, lateral view 9 female intermediate tergite, dorsal view. Scale bars: 0.5 mm (1–6, 8, 9), 0.1 mm (7).
Cephalic plate: breadth/length ratio 1.04 (length 1.20 mm, breadth 1.23 mm); much broader than forcipular T (breadth 0.90 mm) (Fig.
Tarsal articulation of all legs distinct (Figs
Plectrotaxy of L. yuchernovi sp. n. Holotype. Brackets show the presence of an asymmetric spine in one of leg pairs.
Leg | Ventral | Dorsal | ||||||
t | P | F | Ti | C | P | F | Ti | |
1 | – | – | a m | m | – | p | a | a |
2 | – | – | a m | m | – | p | a p | a |
3 | – | – | a m | m | – | p | a p | a (p) |
4 | – | – | a m | m | – | p | a p | a p |
5 | – | – | a m | m | – | (a) p | a p | a p |
6 | – | – | a m | (a)m | – | a p | a p | a p |
7 | – | (m) | a m | a m | – | a p | a p | a p |
8 | – | m | a m | a m | – | a p | a p | a p |
9–11 | – | m p | a m p | a m | – | a p | a p | a p |
12 | – | m p | a m p | a m | – | a m p | a p | a p |
13 | – | m p | a m p | a m | a | a m p | p | p |
14 | m | a m p | a m | m | a | a m p | p | – |
15 | m | a m p | a m | – | a | a m p | – | – |
Paratype ♂♂. Length 10.2–12.2 mm. All characters as in holotype, but ocelli 8–10, usually 9 (Figs
Paratype ♀♀. Length 12.1–16.0 mm. Antennae usually with 20+20 segments, but in two specimens 20+19 and 20+18, respectively; 3 specimens with broken antenna (20+?). Intermediate tergite broadened, breadth/length ratio 1.19 (length 0.80 mm, breadth 0.95 mm) (Fig.
Lithobius (Chinobius) yuchernovi sp. n., male paratype. 13 leg 14, lateral view 14 leg 1, lateral view 15 leg 15, lateral view 16 prefemur and femur of leg 15, dorsal view 17 tibia 15, ventral view 18 genital sternite with gonopods, ventral view 19 tarsus 15, lateral view 20 antenna. Scale bars: 0.1 mm (18), 0.5 mm (13, 14, 16, 17, 19), 1 mm (15, 20).
Although males from different localities in northeastern Siberia show relatively stable morphological features, females from various places demonstrate certain variability in the structure of the gonopods. Thus, in females from Chukotka, the lateral denticles on the gonopodal claw are better expressed (Fig.
Lithobius (Chinobius) yuchernovi sp. n., female paratype (21–24, 26) and non-type females (25, 27–28). 21, 23 forcipule and dental margin of forcipular coxosternite, ventral view 22 gonopod, ventral view 24 gonopod, dorsal view 25 gonopod, ventrolateral view (Chukotka) 26 ocelli and Tömösváry’s organ, lateral view 27 gonopod, dorsolateral view (Magadan Region) 28 same (Kamchatka Peninsula). Scale bars: 0.5 mm (21), 0.1 mm (22–28).
Almost all specimens were collected in montane environments (800 to 1470 m), with only a few obtained from a plain area at ca 60 m near the town of Anadyr. In the mountains, the new species dwells in mountain Betula forest, alpine meadow, montane tundra with Dryas dwarf bush and Cassiope tetragona nival habitats.
As a nomenclatural remark, Lithobius zachiui nom. n., is proposed herewith as a new replacement name for Lithobius (Chinobius) orientalis (Matic, 1973). The name Lithobius (Chinobius) orientalis (Matic, 1973) must be considered as permanently invalid (
Another nomenclatural remark, Lithobius carli nom. n., is proposed herewith as a new replacement name for Lithobius (Alokobius) orientalis Attems, 1953. This name must be considered as permanently invalid (
Males of L. yuchernovi sp. n. differ from those of all known Palaearctic species of the genus Lithobius by the presence of a distoventral tubercle on Ti 15. Based on the structure of the gonopod, females are close to species of the subgenus Chinobius, from which they differ by following morphological details of the body. Thus, our new species is distinguished from L. (Ch.) orientalis Sseliwanoff, 1880 by the 20-segmented antennae (vs. 19-segmented); from L. (Ch.) zachiui nom. n. by the non-swollen gonopodal segment 2 and the presence of 6–8 dorsal short spines on it (vs. segment 2 swollen and spineless); from L. (Ch.) pectinatus Takakuwa, 1939 by the presence of a well-defined denticle on the external ridge of the claw and thick spurs (vs. without such a denticle and with very thin spurs).
Based on the structure of the female gonopod and other main characters (body length, number of antennomeres and ocelli, 2+2 coxosternal teeth, tergites without posterolateral triangular projections), L. yuchernovi sp. n. also resembles L. otasanus Takakuwa, 1941, a species described from the southern Sakhalin Island (
In addition, females of the new species are close to the northern Pacific species Lithobius (Ezembius) stejnegeri (Bollman, 1893) which inhabits Alaska, the Pribilof and Commander Islands, as well as some Aleutian Islands. However, L. yuchernovi sp. n. differs by the presence of 2 or more lateral denticles on the internal ridge of the gonopodal claw (vs. a tripartite or simple gonopodal claw in young and adult females, respectively (
Another patronym in lithobiid taxonomy that honours Academician Y.I. Chernov is worth mention. This is Lithobius (Monotarsobius) chernovi (Zalesskaja, 1976), described from the Taymyr Peninsula in the Far North of Russia. The valid name for L. (M.) chernovi is Lithobius (Monotarsobius) alticus (Loksa, 1965) (
Originally,
The taxonomic problems existing within Chinobius were discussed by
On the other hand, females of L. (Ch.) yuchernovi sp. n. from the Kamchatka Peninsula are extremely similar to those of L. (E.) stejnegeri Bollman, 1893. When redescribing L. (E.) stejnegeri from Kamchatka and the Iturup Island, Kuriles,
As a result, Kamchatka appears to harbour both these species which are best distinguished based on male specimens, whereas females are difficult to separate. Whether these species occur not only sympatrically, as is the case concerning the Kamchatka Peninsula, but also syntopically remains open to question.
Males of the new species are characterised by a feature unique among the Palaearctic Lithobiinae Verhoeff, 1907, i.e. a distoventral rounded tubercle supporting a group of setae on Ti 15. In addition, they show more or less strongly expressed dorsal and ventral sulci on ultimate legs. Similar distoventral modifications of male Ti 15 are observed in the North American genus Nothembius Chamberlin, 1916. L. yuchernovi sp. n. seems to be particularly close to N. aberrans Chamberlin, 1916 (see
The authors wish to thank S.I. Golovatch (Moscow, Russia) for editing an advanced draft. The first co-author is most grateful to S.L. Esyunin (Perm, Russia) for his constant guidance, encouragement and support. The authors are thankful to A.V. Grischenko, Head of the Zoological Museum of the Perm State University, for the assistance in using the SEM facilities. Special thanks go to O.L. Makarova, A.B. Babenko and A.A. Schileyko (all Moscow) for the provision of material for study.