Lithobius (Chinobius) yuchernovi, Farzalieva, Gyulli Sh., Nefediev, Pavel S. & Tuf, Ivan H., 2017

Farzalieva, Gyulli Sh., Nefediev, Pavel S. & Tuf, Ivan H., 2017, Lithobius (Chinobius) yuchernovi, a new lithobiid species from northeastern Siberia and the Kamchatka Peninsula, Russia (Chilopoda, Lithobiomorpha), ZooKeys 693, pp. 95-108 : 95-97

Lithobius (Chinobius) yuchernovi sp. n. Figs 1-9, 10-12, 13-20, 21-28

Type material.

Holotype ♂ (ZMUM): Russia, Magadan Region, Kolyma Uplands, Ola Plateau highlands, 60°39'N, 151°16'E, nival community with Cassiope tetragona , 1275 m, 9.08.2011, leg. O.L. Makarova and A.B. Babenko.

Paratypes: 3 ♂♂, 4 ♀♀ (ZMUM), 2 ♂♂, 1♀ (MMUM, No. G7593), same data as holotype; 5 ♂♂, 4 ♀♀ (PSU), same locality, grass meadow, forb meadow with abundant legumes, nival community with Cassiope tetragona , dryas-forb tundra and ridge-top dryas-moss tundra, ca 1225-1470 m, 8-9.08.2011, leg. O.L. Makarova and A.B. Babenko; 5 ♂♂, 5 ♀♀ (ZMUM), 3 ♂♂, 12 ♀♀ (PSU), same locality, along bed of a nameless stream, at timber line, snowbed at ca 1150 m, 10.08.2011, leg. O.L. Makarova and A.B. Babenko; 3 ♂♂, 6 ♀♀ (PSU), same locality, forest belt of Ola Valley, willow bog, ca 820 m, 10.08.2011, leg. O.L. Makarova.

Non-type material: Chukot Autonomous Region: 6 ♂♂, 5 ♀♀, 1 subadult ♀ (ZMUM), environs of Anadyr Town, Maria Hill, under stones, 14-17.07.1971, leg. A.L. Tikhomirova and V.A. Turchaninova; 1 ♂, 7 ♀♀ (ZMUM), upper reaches of Bolshaya Osinovaya River, 66°52'N, 175°13'E, 30.07.1992, leg. D.I. Berman; 1 ♂ (ZMUM), near Markovo, 64°41'N, 170°26'E, spring alluvium of Anadyr River, 9.07.1971, leg. A.L. Tikhomirova; 8 ♂♂, 1 subadult ♂, 1 ♀♀ (ZMUM), Anadyr River, estuary of Balaganchik River, 64°54'N, 168°36'E, no date, leg. P.S. Tomkovich; 3 ♂♂, 16 ♀♀, 11 epimorph juveniles (PSU), Chaun Bay, Mt. Neitlin, 69°19'N, 171°27'E, pitfall traps, 5-25.08.1992, leg. D.I. Berman. Kamchatka Peninsula: 1 ♂ (ZMUM), near Elizovo, 53°10'N, 158°28'E, Betula forest with Poaceae , 11.08.1987, leg. A.V. Tanasevitch; 1 ♂, 1 ♀ (ZMUM), Kronotsky Nature Reserve, near Valley of Geysers, 54°31'N, 159°48'E, mountain tundra with mosses and lichens,1200 m, 2-3.09.1978, leg. A.V. Tanasevitch; 1 ♂, 3 ♀♀ (ZMUM), same locality, multiherbaceous Betula forest on slope, 1.09.1978, leg. A.V. Tanasevitch; 2 ♀♀ (ZMUM), southern border of Kronotsky Nature Reserve, Zhupanovo, Abies forest, 30.08.1987, leg. A.V. Tanasevitch. Magadan Region: 19 ♂♂, 49 ♀♀, Tenkinsky District, near Sibik-Tyellakh, “Aborigen” Field Station, 61°54'N, 149°18'E, Mt. Medvezhya, no date, leg. D.I. Berman; 1 ♂, 1 ♀ (ZMUM), Annachag Mts, Jack London Lake, 62°04'N, 149°31'E, ca 800 m, litter, 5-6.08.1985, leg. Lyubimova.

Name.

The new species honours Academician Yury Ivanovich Chernov (1934-2012), the outstanding researcher of the Arctic ( Reznikova 2012).

Diagnosis.

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.

Distribution

(Figure 29). Northeastern Siberia and the Kamchatka Peninsula.

Description.

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. 1); posterior margin of intermediate T straight, breadth/length ratio 1.04 (length 0.68 mm, breadth 0.70 mm); T 10 broadened, breadth/length ratio 1.16 (length 1.23 mm, breadth 1.43 mm). Sternites: sparsely setose, breadth/length ratio of S 10, 1.23 (length 0.88 mm, breadth 1.08 mm); breadth/length ratio of S 15, 0.65 (length 0.55 mm; genital sternite more densely setose, as in Fig. 18).

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. 2). Antennae: ca 5.25 mm long, reaching the middle of T 6, composed of 20+19 elongate articles (Fig. 20). Ocelli: 11 on each side, dark, arranged in three broken rows; posterior ocellus slightly larger than posterosuperior ocellus and other seriated ocelli. Tömösváry’s organ as large as nearest ocellus, rounded (Figs 8, 26). Forcipular coxosternite: dental margin slightly concave, with 2+2 acute teeth and setiform porodonts, median diastema V-shaped; shoulders of coxosternite strongly sloping, as in Figs 4 and 23.

Tarsal articulation of all legs distinct (Figs 13-15). Legs 14 slightly incrassate, without visible modifications (Fig. 13). P, F, Ti and Ts1 of legs 15 incrassate, last three with modifications: F with a clearly expressed dorsal sulcus and a poorly-developed ventral one; Ti with a poorly-expressed dorsal sulcus and a well-developed ventral sulcus, the latter reaching the distoventral tubercle supporting a cluster of curved and long setae (distal setae more strongly curved, unciform, proximal ones almost straight) (Figs 12, 15); Ts1 slightly flattened, dorsally with an implicit impression (Fig. 11) bearing a few erect setae. Length of legs 15: P = 0.78, F = 0.83, Ti = 0.83, Ts1 = 0.83, Ts2 = 0.48. Legs 13-15 with DCa. Accessory claw on leg 15 large, well-developed. Plectrotaxy as in Table 1. Coxal pores: present on legs 12-15, rounded, separated from one another by distances 2-2.5 times greater than their own diameter; inner pores smaller than neighbouring ones; formula 3, 4(5), 4(5), 4. Gonopod 1-segmented, with three setae (Figs 7, 18).

Paratype ♂♂. Length 10.2-12.2 mm. All characters as in holotype, but ocelli 8-10, usually 9 (Figs 8, 26). Antennae normally with 20+20 segments, but 3 specimens with asymmetric numbers of antennal articles (19+20, 20+19 and 18+20); 6 specimens with broken antenna (20+?). Posterior and posterosuperior ocelli slightly different in size from seriate ocelli. All specimens with a well-visible distoventral tubercle, the latter carrying a group of straight or curved setae. Expression of other sulci on legs 15 variable: in some males, dorsal sulci on F and Ti poorly visible or absent at all, while in others, ventral sulci not developed. In some specimens, dorsal impression on Ts1 without erect setae (Fig. 11). Plectrotaxy as in holotype, but in some specimens Vtm can start with legs13, while VTia from legs 3 to 14. Coxal pores as in holotype, their number varying from 3 to 5. Gonopods as in holotype, with 2-3 setae (Figs 7, 18).

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. 9). Legs 12-15 with 4-6 coxal pores, formula 4(5),5(4),5(4),5(6). Gonopods without setae on internal face, with 2+2 short spurs separated from one another by distances not exceeding the diameter of the widest part of a spur (Figs 5, 22). First segment of gonopod without spines, second with 6-8, third with 2-3 dorsal short spines in two uneven rows (Figs 6, 24). In some specimens, the spines very short. Apical claw of gonopod with one well-defined lateral denticle located in the middle of external ridge, as well as with 2-4 blunt denticles on internal ridge. In some specimens, the denticles almost abraded. In most specimens, the lateral denticles on internal ridge of claw blunt, as in Figs 27 and 28. Other characters as in holotype.

Variation.

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. 25) than in the type material from the Magadan Region (Figs 5, 22). The Kamchatka specimens differ from all others to the greatest extent: both sexes are with faint, but still visible tarsal articulations on the first eleven pairs of legs (in one large male, the tarsal articulations were truly distinct); males with the distoventral tubercle on Ti 15 that supports fewer setae and less strongly expressed dorsal and ventral sulci. In females, the lateral denticle on the external ridge of the gonopodal claw is very weakly expressed, up to absent in some females. In addition, the internal ridge of the claw with one well-expressed and one almost abraded denticle, the latter looks like an uneven edge at the claw base (Fig. 28).

Habitats.

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.