Ctenolepisma turkestanicum, Kaplin & Shakula, 2022

Kaplin, V. G. & Shakula, G. V., 2022, A new species of silverfish of the subfamily Ctenolepismatinae (Zygentoma: Lepismatidae) from southern Kazakhstan, Zoosystematica Rossica (China) 31 (1), pp. 111-117 : 112-116

Ctenolepisma turkestanicum sp. nov.

( Figs 1–21)

Holotype. Male , Kazakhstan, Turkistan Prov., Turlanskiy Pass, 43°33′N 68°57′E, 949 m, under flat stones, 13.X.2020, G. Shakula leg.

Paratypes. 3 males, with same data as for holotype .

The holotype and one paratype are mounted on slides; two paratypes are kept in 70% ethanol.

Description. Male. Medium-sized silverfish. Body noticeably elongate, with thorax slightly wider than abdominal segment I.

Body length (including head): 10.1–10.8 mm. Ratio of head length to whole body length about 0.06–0.07, that of thorax to whole body about 0.32, abdomen to whole body about 0.61–0.62. Width of head 1.50–1.65 mm; width of thorax 2.25–2.50 mm; width of abdomen 2.0– 2.3 mm; width of urotergite X 1.25–1.50 mm.

General body colour (in ethanol-preserved specimens) whitish with purple pigment being stronger on head around eyes and at bases of following appendages: antennae, paraprocts, epiproct, cerci and median dorsal appendage. Weaker pigment extending on occiput, vertex, frons, scapus and pedicellus, urotergites I–X, and male genital appendages. Scales on upper side of body brownish ginger, on lower side light brown.

Macrochaetae pectinate, bifid apically. Scales multiradiate of variable shape, rounded, oval, and suboval.

Antennae damaged in all specimens; maximum length of preserved part of antenna 8.5–9.5 mm (or 0.82–0.88 of body length); terminal filaments damaged in all specimens. Distal preserved segments of flagellum divided into six annuli. Ratio of length to width of scapus about 1.3–1.4. Ventral side of pedicellus with two longitudinal rows of short sensory chaetae ( Fig. 2).

Head 2.0–2.3 times as wide as long. Eyes black, well-developed; eye diameter about 0.20–0.22 mm. Macrochaetae well-developed along anterior and lateral margins of head, relatively large, pectinate, bifid apically ( Fig. 3). Frons, gena, clypeus and labrum in anterolateral and lateral parts with numerous large pectinate apically bifid macrochaetae; middle parts of frons, gena, clypeus and labrum without macrochaetae.

Mandible with well-developed molar and incisor areas, with five strong chitinised teeth: two smaller and three larger ones, of which two sharp and one wide ( Fig. 4); mandible with numerous relatively long setae being bifid apically; molar area of mandible with macrochaetae and with a row of shorter lateral chaetae including about 11–14 smooth, apically bifid chaetae near incisor area.

Maxilla without peculiar characters; lacinia with three strong teeth (two large and one more smaller), seven lamellate processes and a row of seven simple chaetae; galea laterally with 11–14 small and 4–5 longer chaetae. Apical segment of maxillary palp 1.01–1.16 times as long as penultimate segment ( Fig. 5).

Labium broad; postmentum with a row of relatively large, smooth, apically bifid chaetae. Labial palp well-developed; apical palpomere oval, with five papillae, ratio of its length to width approximately 1.6–1.7 ( Fig. 6).

Legs fairly long, running ( Fig. 7).

Hind legs about 1.2 times as long as fore and middle legs. Coxae, femora and tibiae covered with scales. Ratios of total lengths: PI to PII about 1.02,

PIII to PII 1.19, PIII to PI 1.16. Ratios of length to width in leg segments as in

Table 1. Middle and hind femora and coxae most widened. Ratio of length of first tarsomere of hind tarsus to total length of hind tarsus about 0.60.

Pretarsus with lateral claws relatively long, slightly curved ( Fig. 8). Fore tarsus and middle tarsus 1.40 times as long as respective tibia; hind tarsus

1.25 times as long as hind tibia.

Prosternum ( Fig. 9) subtriangular.

Mesosternum ( Fig. 10) and metasternum ( Fig. 11) semioval, rounded apically. Pro-, meso- and metasternum almost reaching apex of coxae of fore, middle and hind legs, respectively. Ratio of length to width of thoracic sterna about

1.05–1.10, 0.95–1.05 and 0.75–0.90,

respectively. Distal parts of sterna with bristle combs: they located in about onethird of prosternum length, in about one-quarter of mesosternum length and in one-tenth part of metasternum length. Distal part of prosternum with 3 + 3 bristle combs, that of mesosternum with 1–2 + 1–2 combs, preapical part of metasternum with 1 + 1 combs, including 3–8, 5–11 and 11–14 large pectinate macrochaetae, respectively. All thoracic sterna with hyaline scales. Anterior margin of pronotum with interrupt- ed chaetal collar. Lateral margins of thoracic nota with 8–10 + 8–10 bristle combs, including 3–5, less often 2 or 6, long, pectinate, apically bifurcate macrochaetae and with 2 + 2 open trichobothrial areas with one thin, very long trichobothrium in lateral combs ( Figs 14, 15). Posterior trichobothrial areas associated with posterior combs on all thoracic nota. Anterior trichobothrial areas associated with comb N-4 from posterior margin of pronotum, N-2 of mesonotum and N-3 of metanotum. Posterior margins of pro-, meso- and metanotum with 1 + 1 sublateral bristle combs including 6–7 pectinate macrochaetae.

Numbers of macrochaetae in abdominal bristle combs as in Table 2. Urosternites I and II without bristle combs. Urosternites III–VIII with 1 + 1 sublateral bristle combs of 10–16 pectinate macrochaetae ( Fig. 12). Urotergite I with 1 + 1 bristle combs ( Fig. 13), urotergites II and VIII with 2 + 2, urotergites III–VII with 3 + 3, urotergite X with 1 + 1 combs including 6–9, 9–13, 7–13 and 8–9 pectinate macrochaetae, respectively. Urotergite IX without bristle combs. Urotergite X trapezoidal ( Figs 16–19).

Abdominal segments VIII and IX with two pairs of styli (urostyli). Stylus of segment IX 1.3 times as long as stylus of segment VIII. Ratio of lengths of coxites to styli of segment IX about 1.5–1.6. Penis typical of genus Ctenolepisma . Male parameres absent ( Figs 20, 21).

Etymology. The species name is an adjective referring to the region of Turkestan in southern Kazakhstan, where the type specimens were collected.

Comparison. Ctenolepisma turkestanicum sp. nov. is the first species of the genus Ctenolepisma with 2 + 2 bristle combs on urotergite II. All described species of this genus have 3 + 3 bristle combs on urotergite II. The new species is most close to C. przewalskyi Kaplin, 1982 described from the lower belt of the Kyungei-Ala-Too Ridge in Kyrgyzstan ( Kaplin, 1982). Both spe - cies are characterised by 3 + 3 bristle combs on urotergites III–VII, 1 + 1 bristle combs on urosternites III–VIII, two pairs of the urostyli, and five sensory papillae on the apical segment of labial palp. However, in addition to the number of bristle combs on urotergite II, these species differ from each other in the distribution of hypodermal pigment and the number of bristle combs on the thoracic sternites. The body of C. przewalskyi is strongly pigmented, vs. mostly whitish in C. turkestanicum sp. nov. The prosternum of the new species has 3 + 3 combs, the mesosternum, 1–2 + 1–2 combs, and the metasternum, 1 + 1 combs, while C. przewalskyi has 3–4 + 3–4, 2–3 + 2–3 and 2 + 2 bristle combs, respectively.