Coryphophthalmus Verhoeff, 1910

Kaplin, V. G. & Koval, A. G., 2021, A new species of bristletails of the genus Coryphophthalmus Verhoeff, 1910 (Microcoryphia: Machilidae) from Krasnodar Region, Russia, Caucasian Entomological Bulletin (Caucas. entomol. bull.) 17 (1), pp. 155-161 : 155-161

Genus Coryphophthalmus Verhoeff, 1910

Type species: Coryphophthalmus banaticus Verhoeff, 1910 .

Coryphophthalmus aureaocellus Kaplin , sp. n.

( Figs 1–13)

Material. Holotype, ♂ (in slides): Russia, Krasnodar Region, Sochi National Park, NW Caucasus, Dzykhra Mountain Range , 43°34′N / 40°04′E, 840 m, 14.09.2019 (A.G. Koval) . Paratype: 1♀ (in slides), same data as for holotype .

Description. Body length 9–9.5 mm, width 2.2–2.6 mm; cerci length about 4.5 mm (male, apical article slightly broken); total eyes width of male 0.99 mm, female 1.09 mm, eye length 0.51 mm (male) and 0.56 mm (female); paired ocelli width and length 0.27 and 0.23 mm, in both sexes, respectively; coxal styli length about 0.9 mm (male) or 0.7 mm (female); ovipositor length 1.4 mm. Antennae slightly longer than body, cerci of female broken. General body colouration whitish or light brownish, with brown and violet hypodermal pigment of weak or medium intensity on head (frons, gena, occiput, maxillae, mandibulae), coxae. Scale colour on upper and lower surface of body whitish, brown or dark brown. Distal chains of flagellum divided into 8–10 annuli ( Fig. 1). Clypeus of male and female missing long thin chaetae.

Compound eyes dark or almost black (in ethanol). Ratio of length to width ratio of compound eye about 1.03–1.04; ratio of contact line to length of eye 0.51–0.53, in both sexes ( Fig. 2). Paired ocelli submedian, pyriform, golden-light brown with narrow white borders. Ratio of width to length of paired ocellus 1.2. Ratio of distance between inner and outer margins of ocelli to total width of compound eyes, respectively 0.16 (male) or 0.18 (female) and 0.61 (male) or 0.68 (female).Frons between the paired ocelli is convex.

Apical palpomere of maxillary palp 0.75–0.76 times length of preceding one, in both sexes; ratio of lengths of 5 th and 4 th palpomeres about 1.15 (male) or 1.42 (female). Dorsal surface of 7 th, 6 th and 5 th palpomeres of maxillary palp with 11–12, 13–14 and 4–5 (male) or 16, 17–20 and 5 (female) hyaline spines, respectively ( Fig. 3). Undersurface of 2 nd –5 th palpomeres and basal part of 6 th palpomere of male maxillary palp with relatively numerous and long thin chaetae, missing on its labial palpomeres.Undersurfaceof apical palpomere and distal part of 6 th palpomere of maxillary palp and dorsal surface of 1 st –3 rd palpomeres of labial palp with numerous, relatively straight and more shorter chaetae.Apical palpomere of labial palp triangular, considerably extended (male) or triangularly oval (female) with about 55 or 32 sensorial cones, respectively. Ratio of its length to width about 0.8 and 2–2.1, respectively ( Figs 4, 5). Mandibles with four distal teeth, in both sexes ( Figs 6, 7).

Fore femur of male and female slightly widened. Legs relatively long, running. Middle legs shorter than fore and hind legs 1.23–1.25 and 1.11–1.15 times, respectively, in both sexes. Ratios of length to width of femur, tibia and tarsus as shown in Table 1. Ratio of length of 3 rd tarsomere of hind tarsus to its total length 0.29–0.3, in both sexes ( Fig. 8). The claws of pretarsa are relatively long. Hyaline spine-like chaetae on undersurface of femora, tibiae and tarsi are missing. Ratio of length of styli to width of middle coxae about 1.8, in both sexes, but to width of hind coxae 1.9 (male) or 1.5 (female).

Urocoxites I, V–VII with 1 + 1, II–IV with 2 + 2 eversible vesicles. Length ratios of urosternites, urocoxites and urostyli are shown in Table 2. Posterior angle of urosternites and distribution of sublateral spines on urocoxites and urotergites are given in Table 3. Urocoxite VII of female with protruding lobes between eversible vesicles. Ratio of length to width of one lobe about 0.6 ( Fig. 9). Undersurface of distal part of male urocoxites IX also with several relatively long chaetae.

Male genitalia with one pair of parameres on urite IX. Parameres with 1 + 6 divisions, slightly surpassing apex of penis. Penis and parameres clearly not attaining level of apex of urocoxites IX, ratio of the distance between apexes of parameres and of urocoxites IX to width of distal division of penis about 7. Basal division of penis 1.2 times longer than distal division ( Fig. 10).

Ovipositor slender, elongate, slightly surpassing apex of styli IX ( Fig. 11). Anterior and posterior gonapophyses with approximately 41 or 42 divisions, respectively. One basal divisions of anterior gonapophyses and about 18–19 basal divisions of posterior gonapophyses glabrous. Distal spines of gonapophyses as long as 3–4 apical divisions combined. Distal divisions of anterior and posterior gonapophyses with 5–9 and 4 chaetae, respectively (not including apical spines) ( Figs 12, 13).

Differential diagnosis. Between species of the subgenus Coryphophthalmus s. str. with 2 + 2 eversible vesicles on urites II–IV C. aureaocellus sp. n. belongs to a group species with a body length of 7–12 mm, distal chains of the flagellum are divided into 8–11 annuli, dark with blue tint eyes, brown paired ocelli, the ratio of length to width of compound eye is about 1, the length of the contact line between compound eyes is about 0.5–0.6 of the eye length; the ratio of distance between inner and outer margins of ocelli to the total width of compound eyes is 0.13–0.18 and 0.6–0.7, respectively; the undersurface of 2 nd –7 th palpomeres of the male maxillary palp is with relatively numerous and long thin chaetae, without hyaline spine-like chaetae on undersurface of femora, tibiae and tarsi; ovipositor is with approximately 41–42 divisions, parameres of the male are usually with 1 + 6 divisions. This group includes about six known species: C. aureaocellus sp. n., C. lineatus (Kaplin, 2015) , C. lapidicola Kaplin, 2020 , C. divnogorski (Kaplin, 2010) , C. silvestris Kaplin, 2020 and C. borgustani (Kaplin, 2015) . Coryphophthalmus aureaocellus sp. n. differs from other described species of the subgenus Coryphophthalmus s. str. by the colouration of paired ocelli, a sharp sexual dimorphism in the structure of the apical palpomere of the labial palp; from species of this group in the length of cerci, the chaetotaxy of the male maxillary palp, ratios of width to length of the paired ocellus, of the length of the 3 rd tarsomere of the hind tarsus to its total length. The main differences between species of this group are summarized in Table 4.

Habitats. Specimens of Coryphophthalmus aureaocellus sp. n. were collected in mountain forest (Fagus, Quercus, Hedera colchica), on the trunks of the oriental beech Fagus orientalis, active at night. During the day time they hide in the forest litter, 840 m above sea level.

Etymology. The new species takes its name from the colouration of its paired ocelli.