Trigoniophthalmus tseyi Kaplin, 2019

Kaplin, V. G., 2019, New species of bristletails of the genus Trigoniophthalmus Verhoeff, 1910 (Archaeognatha: Machilidae) from North Ossetia - Alania (Russia), Caucasian Entomological Bulletin (Caucas. entomol. bull.) 15 (1), pp. 25-34 : 28-31

Trigoniophthalmus tseyi Kaplin , sp. n.

( Figs 16–28 )

Material. Holotype, ♂ (in slides): Russia, North Ossetia – Alania, Alagir Distr., Verkhniy Tsey settl.,environs of Recom sanctuary, 42 ° 47′31ʺN / 43 ° 54′14ʺE, 1950 m, 28.04.2018 ( V. G. Kaplin) . Paratypes: 1♂, 2♀ (1♀ in slides), same data as for holotype .

Description. Body length: male 7–7.5 mm, female 7.3–8 mm. Body width: males and females 1.8–2.1 mm. General body color whitish. Antennal base, frons, maxillae, mandibles, hypopharynx with brown hypodermal pigment of weak and medium intensity. Color of scales on surface of body brownish. Antennae slightly shorter than body. Distal chains of flagellum divided into 9–12 articles in male and female ( Fig. 16 ). Clypeus of male with long thin bristles. Cercus approximately 0.41–0.46 body length, including about 17 articles in both sexes. Apex of cercus with one spike ( Fig.17 ). Articles of cerci, except apical one in female and two distal ones in male, with 1 or 2 colorless supporting macrochaetae on the inner side. Cerci of female also with 3 or 4 macrochaetae on outer side, male with only 1 macrochaeta in such position. Supporting macrochaetae also present on lateral sides of articles of caudal filament.

Compound eyes black (in ethanol). Ratio of length to width of compound eye about 1.02–1.04 in males and 1.04–1.06 in females; ratio of length of contact line to length of eye 0.50–0.54 in both sexes. Paired ocelli submedian, pear-shaped, brown with a welldefined white border, 1.4–1.6 times as wide as long in both sexes. Distance between inner margins of ocelli about 0.16–0.18 and between their outer margins 0.60–0.65 total width of compound eyes in both sexes ( Fig. 18 ).

Apical article of maxillary palp 0.77 (male) or 0.82 (female) times as long as preceding one. Dorsal surface of 7 th, 6 th and 5 th articles of maxillary palp in both sexes with 11–13, 11–13 and 4 hyaline spines, respectively. Ventral surface of 2–7 th articles of male maxillary palp with relatively numerous and long thin chaetae, on sixth and especially seventh articles such chaetae distributed more sparse ( Fig. 19 ). Similar long thin chaetae also present on dorsal surface of 2 nd and 3 rd articles of male labial palp. Apical article of labial palp triangularly oval, 2.2 (male) or 2.3 (female) times as long as wide ( Fig. 20 ). Mandibles with 4 distal teeth ( Fig. 21 ).

Fore femur and tibia of male and female widened, without sensory field ( Fig. 22 ). Ratios of length to width of femur, tibia and tarsus as shown in Table 4 . Ratio of length of 3 rd tarsomere of tarsus to total length of tarsus 0.33–0.35 in both sexes. Coxa of male with long, thin bristles, missing from the femur, tibia and tarsus. Ventral surface of femur, tibia and tarsus with colorless spine-like chaetae ( Table 5 ). Middle and hind legs with coxal styli. Length of styli 0.5 mm (female) or 0.6 mm (male). Ratio of length of styli to width of middle and hind coxae about 1.4–1.5 in both sexes. Praetarsus with 2 claws and support cone-shaped projection between them. Ratios of length to width of projection 1.9–2.1, widths of projection and pretarsus about 0.3.

Posterior margin of pronotum with a deep notch. In both sexes, urites I and V–VII with 1 + 1 eversible vesicles, but urites II–IV with 2 + 2 eversible vesicles ( Figs 24, 25 ). In male, posterior angle of urosternites II, III–VI, VII approximately 78°, 71–73° and 68°; but in female, 84°, 73–75° and 65°, respectively. In male, posterior angle of urosternite VIII about 84°. Ratios of lengths of styli (without apical spines) and urocoxites II–IX as shown in Table 6 . Inner posterior lobes of urocoxites VII between eversible vesicles of female protruding ( Fig. 25 ); ratio of length to total width of these lobes about 0.7. Thoracic tergites, urotergites I–IV, urosternites and urocoxites I–VI without macrochaetae in both sexes. Distribution of sublateral macrochaetae on urotergites V–X and spines on urocoxites VII–IX as shown in Table 7 .Urocoxites IX, respectively, with 2 and 7–8 (male) or 1 and 7–11 (female) outer and inner sublateral spines ( Figs 23 , 26 ).

Ovipositor slender, elongate (1.6–2.1 mm), slightly not surpassing apex of styli IX ( Fig. 26 ). Anterior and posterior gonapophyses with approximately 47 and 50 divisions, respectively. Two basal divisions of anterior gonapophyses and about 27 basal divisions of posterior gonapophyses glabrous. Apical macrochaetae of gonapophyses as long as four apical divisions combined. Distal divisions of anterior gonapophyses with 4–6, posterior gonapophyses with 2–5 setae (not counting sensory setae and apical macrochaetae) ( Figs 27, 28 ).

Male genitalia with one pair of parameres on abdominal segment IX. Parameres with 1 + 7 divisions, penis slightly not attaining apex of parameres ( Fig. 23 ). Penis and parameres not attaining of apex of coxites IX for 4.6 of width of aedeagus. Phallobasis of penis 1.3 times as long as aedeagus.

Differential diagnosis. Trigoniophthalmus tseyi sp. n. belongs to the same species group as T. kobani sp. n. described above. Trigoniophthalmus tseyi sp. n. differs from other species of this group by ratio of distance between inner margins of paired ocelli to total width of eyes, presence of spine-like setae on legs, small posterior angle of urosternites II–V, large number of inner sublateral spines on urocoxite IX. Main differences between these species of this group are in Table 8 .

Habitats. Specimens of Trigoniophthalmus tseyi sp. n. were collected in mountain forest (Pinus, Fagus, shrubs) under stones, 1950 m above sea level.

Etymology. The new species takes its name from the type locality: Verkhniy Tsey, North Ossetia – Alania.

Figures

Figs 16–23. Trigoniophthalmus tseyi sp. n., male, holotype. 16 – distal chain of antennal flagellum; 17 – apex of cercus; 18 – eyes and paired ocelli; 19 – maxillary palp; 20 – labial palp;21 – distal part of mandible; 22 – fore leg (part); 23 – male genitalia with urocoxite IX. Scale bars 0.1 mm. Рис. 16–23. Trigoniophthalmus tseyi sp. n., самец, гоΛотип. 16 – цепочка ΑистаΛьной части жгутика усиков; 17 – вершина церки; 18 – гΛаза и парные гΛазки; 19 – нижнечеΛюстной щупик; 20 – нижнегубной щупик; 21 – ΑистаΛьная часть верхней чеΛюсти; 22 – переΑняя нога (часть); 23 – поΛовой аппарат самца с кокситом IX сегмента брюшка.Масштабные Λинейки 0.1 мм.

Figs 24–28. Trigoniophthalmus tseyi sp. n., female, paratype. 24 – urosternite and urocoxites IV; 25 – urosternite and urocoxites VII; 26 – ovipositor with urocoxite IX; 27 – apex of anterior gonapophysis of ovipositor; 28 – apex of posterior gonapophysis of ovipositor.Scale bars 0.1 mm. Рис. 24–28. Trigoniophthalmus tseyi sp. n., самка, паратип. 24 – стернит и кокситы IV сегмента брюшка; 25 – стернит и кокситы VII сегмента брюшка; 26 – яйцекΛаΑ с кокситом IX сегмента брюшка; 27 – вершина переΑних створок яйцекΛаΑа; 28 – вершина заΑних створок яйцекΛаΑа. Масштабные Λинейки 0.1 мм.