Leptoiulus tigirek, Mikhaljova, Elena V., Nefediev, Pavel S., Nefedieva, Julia S. & Dyachkov, Yuri V., 2015

Mikhaljova, Elena V., Nefediev, Pavel S., Nefedieva, Julia S. & Dyachkov, Yuri V., 2015, Genus Leptoiulus Verhoeff, 1894 new to the fauna of the Asian part of Russia, with description of a new species from the Altai and its comparison with the European Leptoiulus trilineatus (C. L. Koch, 1847) (Diplopoda, Julida, Julidae), Zootaxa 3974 (2), pp. 267-276 : 268-275

Leptoiulus tigirek sp. nov.

Figs 1–13

Material examined. Holotype: 1 male ( ZMUM: ρ 2656), Russia, Siberia, Altai Province, Krasnoshchekovo District, Tigirek State Nature Reserve, Khankhara site, shrub-reed Larix forest, 21–31August 2012, collected by L.A. Trilikauskas; Paratype: 1 male, 1 female ( IBSS), 1 male, 1 female ( ZMUM: 1m, 1f—ρ 2657), together with holotype, 21–31 August 2012, collected by L.A. Trilikauskas; 1 male, 1 female, 1 juvenile (ASU), Russia, Siberia, Altai Province, Krasnoshchekovo District, Tigirek State Nature Reserve buffer zone, 1.1 km SW Tigirek , 51°09´235´´ N, 83°01´155´´ E, meadow steppe, E slope of stone hill, 525 m a.s.l., pitfall traps, 1–6 July 2013, collected by Yu.V. Dyachkov; 1 male, 1 female (ASU), Russia, Siberia, Altai Province, Krasnoshchekovo District, Tigirek State Nature Reserve buffer zone, 1.5 km NW Tigirek , 51°09´219´´ N, 83°01´146´´ E, Kozyr Mt, Larix sibirica forest, 639 m a.s.l., 2 July 2013, collected by Yu.V. Dyachkov; 2 males, 2 females, 2 juveniles ( IBSS), 2 males, 2 females, 11 juveniles (ASU), Russia, Siberia, Altai Province, Krasnoshchekovo District, Tigirek State Nature Reserve buffer zone, 1.2 km SW Tigirek , 51°07´765´´ N, 83°01´706´´ E, S slope of bottom of Chainaya Mt, Caragana and Lonicera thicket, 619 m a.s.l., 5 July 2013, collected by Yu.V. Dyachkov; 1 male, 2 females, 14 juveniles (ASU), Russia, Siberia, Altai Province, Krasnoshchekovo District, Tigirek State Nature Reserve buffer zone, 3.5 km SW Tigirek , 51°07´212´´ N, 83°00´481´´ E, chern taiga forest, 645 m a.s.l., 8 July 2013, collected by Yu.V. Dyachkov; 4 juveniles (ASU), Russia, Siberia, Altai Province, Krasnoshchekovo District, Tigirek State Nature Reserve buffer zone, environs of Tigirek , 51°09´135´´ N, 83°01´196´´ E, NE slope near top of Kozyr Mt, Larix sibirica and Betula forest, 650 m a.s.l., pitfall traps, 18–28 May 2014, collected by T.M. Krugova; 5 juveniles (ASU), Russia, Siberia, Altai Province, Krasnoshchekovo District, Tigirek State Nature Reserve, Tigirek site, 1.3 km SE Tigirek , 51°08´247´´ N, 83°02´531´´ E, stone hill, shrub thicket of Pentaphylloides fruticosa , 514 m a.s.l., pitfall traps, 1–6 July 2013, collected by Yu.V. Dyachkov; 2 males, 1 female, 45 juveniles (ASU), same locality, 10 July 2013, collected by Yu.V. Dyachkov; 1 male ( ZMUM: 1m—ρ 2658), 4 males, 5 females, 1 fragment (ASU), Russia, Siberia, Altai Province, Krasnoshchekovo District, Tigirek State Nature Reserve, Tigirek site, environs of Tigirek , 51°08´115´´ N, 83°02´501´´ E, left bank of Malyi Tigirek River, bottom of Chainaya Mt, Caragana and Lonicera thicket, 500 m a.s.l., pitfall traps, 18–28 May 2014, collected by T.M. Krugova; 2 males (ASU), Russia, Siberia, Altai Province, Krasnoshchekovo District, Tigirek State Nature Reserve, Tigirek site, environs of Tigirek , 51°07´549´´ N, 83°00´488´´ E, right bank of Malyi Tigirek River, NE slope of bottom of Lvinyi Kamen Mt, chern taiga forest, 675 m a.s.l., pitfall traps, 18–28 May 2014, collected by T.M. Krugova; 4 males, 6 females, 1 fragment (ASU), Russia, Siberia, Altai Province, Krasnoshchekovo District, Tigirek State Nature Reserve, Khankhara site, 7 km NW Tigirek , 51°09´10.36´´ N, 82°56´25.85´´ E, Salix thicket, swamp, 17 August 2014, collected by Yu.V. Dyachkov; 2 males, 14 females (ASU), Russia, Siberia, Altai Province, Krasnoshchekovo District, Tigirek State Nature Reserve, Khankhara site, 6.1 km NW Tigirek , 51°09´15.75´´ N, 82°56´36.35´´ E, Betula and Salix forest, 675 m a.s.l., 18 August 2014, collected by Yu.V. Dyachkov; 2 males, 6 females, 5 juveniles (ASU), Russia, Siberia, Altai Province, Zmeinogorsk District, Tigirek State Nature Reserve, Beloretsk site, 51°00´277´´ N, 82° 45´830´´ E, chern taiga forest, 550 m a.s.l., pitfall traps, 28 May–5 June 2013, collected by T.M. Krugova; 2 males (ASU), Russia, Siberia, Altai Province, Zmeinogorsk District, Tigirek State Nature Reserve, Beloretsk site, 51°00´188´´ N, 82°45´812´´ E, right bank of Glukharikha River at the confluence to Belaya River, upper part of W slope, chern taiga forest, pitfall traps, 2–9 June 2014, collected by T.M. Krugova; 4 females, 1 juvenile (ASU), same locality, pitfall traps, 20–28 August 2014, collected by T.M. Krugova; 3 males (ASU), Russia, Siberia, Altai Province, Zmeinogorsk District, Tigirek State Nature Reserve, Beloretsk site, 51°00´N, 82°45´E, right bank of Glukharikha River at the confluence to Belaya River, lower part of W slope, chern taiga forest, pitfall traps, 3–9 June 2014, collected by T.M. Krugova; 2 females, 4 juveniles (ASU), same locality, pitfall traps, 20–28 August 2014, collected by T.M. Krugova; 2 males, 1 juvenile (ASU), Russia, Siberia, Altai Province, Zmeinogorsk District, Tigirek State Nature Reserve, Beloretsk site, 51°00´211´´ N, 82°45´815´´ E, right bank of Glukharikha River at the confluence to Belaya River, clearing in chern taiga forest, 562 m a.s.l., pitfall traps, 1–9 June 2014, collected by T.M. Krugova; 1 female ( ZMUM: 1f—ρ 2659), 1 female, 3 juveniles (ASU), same locality, pitfall traps, 20–28 August 2014, collected by T.M. Krugova.

Diagnosis. Differs from congeners mainly by the absence of a basal outgrowth on the gonopod promere, more slender gonopod opisthomere and large, blade-shaped phylacum with bifurcated apex.

Description. Male ( Fig. 1 ). Length 20.4–27.7 mm (males with body length 24–25 mm are more common), vertical diameter 1.1–1.3 mm, with 42(–2), 43(–2), 44(–1), 44(–2), 45(–2), 46 (–2), 46(–3), 47(–2) body segments, excluding telson [according to Enghoff et al. (1993), each alternative formula would thus be 40+2+T, 41+2+T, 43+1+T, 42+2+T, 43+2+T, 44+2+T, 43+3+T, 45+2+T] (males with 45(–2) body segments, excluding telson, are more common). Coloration in alcohol dark brown with bluish tinge. Front and caudal parts of body with marbled transverse strips on metazonites. Ventral part of body lighter. Preanal ring of telson dark brown or brown. Head dark brown, clypeolabral region of head brown, ventral part of head light brown. Collum with two transverse, large, marbled brown spots. Antennae dark brown, legs marbled brown, eye patches black.

Eye patches subquadrate, composed of at least 28–30 slightly convex ocelli in adult. Clypeus with or without setae. 1+1 epicranial setae in a transverse row. Supralabral setae 2+ 2 in a transverse row, labral ones 7+7, 8+8. Antennae rather slender and clavate in situ extending behind to segments 3–4. Length ratios of antennomeres 2–7 as 3.8:3.2:3.2:3.6:1.9:1, width ratios as 1.6:1.7:1.7:2.1:1.7:1, respectively. Antennomeres 5 and 6 with an incomplete distodorsal corolla of not less than 6 sensory bacilli. Gnathochilarium distally with two setae on outer edge of each stipites and with one seta closer to medial portion and with low papillate swelling as well as with a group of short setae approximately in the middle of the stipites ( Fig. 2 ). Each lamella lingualis with 4–5 setae arranged longitudinally; length of setae increasing towards apex of lamellae linguales. Genae unmodified. Collum without peculiarities.

Body subcylindrical, slender, somewhat compressed laterally. Prozonite and metazonite separated by distinct suture. Prozonites smooth. Metazona with striae not reaching hind margin dorsally and laterally, but reaching hind margin ventrally. 8–9 striae on metazonital surface between dorsal midline and ozopore. Ozopores small, lying behind suture between pro- and metazona without touching it. Transverse row of sparse, thin, relatively short setae at hind edge of metazonites. Metazonital setae gradually growing longer and denser toward telson. Telson with a relatively long, caudal subcylindrical (at base flattened dorsoventrally) setose projection of epiproct carrying a sharp claw-shaped process directed caudad and somewhat ventrad. Preanal ring of telson covered with relatively long setae. Distal portions of anal valves densely setose. Anal scale subtriangular, setose only along caudal edge.

Slender legs with broad, very delicately serrate sole pads on tibiae and postfemora; these pads gradually growing reduced towards posterior body end to totally disappear on last legs. Claw at base with a thin, setiform accessory claw ventrally but without accessory claw dorsally.

Leg pair 1 ( Fig. 3 ) unciform, with sparse and low papillae apically, 2-segmented telopodites carrying strong setae ventrally, and rounded, low, knob-shaped outgrowth of telopoditomere 2. Each coxa of leg pair 1 with a distal seta. Leg pair 2 unmodified, penes relatively short, apically double, without setae ( Fig. 4 ).

Gonopod pro- and mesomere closely attached to each other ( Fig. 5 , 12–13 ). Coxosternal region poorly developed. Promere ( Fig. 6 ) flattened, caudally papillate, with a flagellum as whip but without remnants of a telopodite and a basal outgrowth. Mesomere ( Figs 5 , 7 , 12 ) very feebly curved caudodistally, distal portion frontally with a shallow spoon-shaped excavation covered with papillae. Opisthomere ( Figs 8–9 ) slender with large broad blade-shaped phylacum (ph) bifurcated apically, claw-shaped velum (v), interior parabasal spine (s), apical and subapical processes.

Female. Length 18.4–36.2 mm (females with body length 31–33 mm are more common), vertical diameter 1.4–2.2 mm, with 43(–2), 44(–1), 44(–2), 45(–1), 46(–1), 46(–2), 47(–1) body segments, excluding telson [according to Enghoff et al. (1993), each alternative formula would thus be 41+2+T, 43+1+T, 42+2+T, 44+1+T, 45+1+T, 44+2+T, 46+1+T] (females with 46(–1) and 47(–1) body segments, excluding telson, are more common). Clypeus with or without setae. Labral setae 7+8, 9+9. Ocelli about 36 in most of the females. About 11 striae on metazonital surface between dorsal midline and ozopore in large females. Other nonsexual characters as in male. Vulvae as in figs 10–11. Operculum with subtriangular apical incision. Two longitudinal rows of setae on operculum each with not less than 10 setae, apical setae longest. Not less than 30 setae on posterior median bursal sclerite; 16–17 setae on lateral and mesal sclerites of the bursa together. Bursal setae gradually elongated to apex of vulva.

Juvenile. Shorter, length of examined specimens varies from 8.9 mm to 20.3 mm, vertical diameter from 0.7 mm to 1.3 mm. Body with 28(–7), 39(–2), 40(–5), 41(–3), 41(–4), 42(–4), 43(–4), 43(–5), 44(–3), 44(–4), 45(–4) segments, excluding telson [according to Enghoff et al. (1993), each alternative formula would thus be 21+7+T, 37+2+T, 35+5+T, 38+3+T, 37+4+T, 38+4+T, 39+4+T, 38+5+T, 41+3+T, 40+4+T, 41+4+T]. Among the juveniles can be recognized subadult males and (possibly) females with 42(–4), 43(–4), 44(–3), 44(–4) body segments, excluding telson [according to Enghoff et al. (1993), each alternative formula would thus be 38+4+T, 39+4+T, 41+3+T, 40+4+T]. Subadult males with normal leg pair 1 and body segment 7 devoid of any extremities; possible subadult females have lesser vulvae.

Name. The specific epithet refers to the type locality, a noun in apposition.

Distribution. The species appears to occur only in the south of Siberia, Russia: Altai Province.

Remarks. The earliest mention of Leptoiulus tigirek sp. nov. as an “undescribed species of Julidae ” belongs to Nefediev et al. (2014), Dyachkov (2014). The species inhabits mainly low-mountain forest and shrub thicket sites at 500–675 m a.s.l., such as chern taiga forests with Abies sibirica and Populus tremula , Larix sibirica and Betula pendula forest, Betula pendula and Salix forest, Salix thicket, shrub thicket of Pentaphylloides fruticosa , Caragana and Lonicera thicket, and also meadow steppe. It predominates in shrub thickets and dark-coniferous forests, making up 74% of all millipede abundance in both types of biotopes ( Nefediev et al. 2014). The numbers range from 1 to 8 ind./m 2 in forest biotopes, and from 10 to 24 ind./m 2 in shrub thicket sites. The maximum locomotor activity is observed in shrub thicket biotopes, ranging from 10 to 22 ind./100 traps per day, whereas the minimum locomotor activity is recorded in forest sites, where it ranges from 1 to 8 ind./100 traps per day.

Figures

FIGURE 1. Leptoiulus tigirek sp. nov., male paratype. Habitus in lateral view. Photographed not to scale.

FIGURES 2 – 5. Leptoiulus tigirek sp. nov., male paratype. 2, gnathochilarium; 3, leg pair 1 (front view); 4, penes and coxae 2; 5, gonopods (mesal view).

FIGURES 6 – 9. Leptoiulus tigirek sp. nov., male paratype. 6, gonopod promere (caudal view); 7, gonopod opisthomere and mesomere (front view); 8, gonopod opisthomere and mesomere (mesal view); 9, gonopod opisthomere (nearly caudal view); ph, phylacum; v, velum; s, interior parabasal spine.

FIGURES 10 – 11. Leptoiulus tigirek sp. nov., female paratype. 10, vulva (caudal view); 11, vulva (lateral view).

FIGURES 12 – 13. Leptoiulus tigirek sp. nov., male paratype. 12, gonopods (mesal view); 13, gonopods (lateral view). Scale in mm.