Allopsontus (Allopsontus) agvalensis, 2020

Kaplin, V. G., 2020, A new species of bristletail of the genus Allopsontus (Microcoryphia: Machilidae) from Dagestan (Russia), Russian Entomological Journal 29 (3), pp. 233-236 : 234-236

Alloposontus (Allopsontus) agvalensis Kaplin , sp.n.

Figs 1–7 .

MATERIAL. Holotype, ♂ Russian Federation, Dagestan, Tsumadinsky District, near Agvali vill. leg. V. Kaplin 27. IV.2019, Andean Koisu River valley, mixed forest ( Quercus , Paliurus spina-christi , Carpinus ), under stones, 975 m, 42°32´20´´N, 46°07´27´´E ( VIZR).

DESCRIPTION (holotype). Body length 9.1 mm, width 2.1 mm; cerci length 3.0 mm; total eyes width 0.85 mm, eye length 0.41 mm; paired ocelli width and length 0.23 and 0.10 mm, respectively; coxal styli length about 0.5 mm. General body color (in alcohol) whitish, or light yellowish, with hypodermal pigment distributed as follows: head (excepting occiput, middle part of clypeus and labrum), mandibles, maxillae, prementum, mentum, 1 st –5 th palpomeres of maxillary palps, thoracic tergites and sternites, coxae, femora and tibiae, urosternites VIII and IX with purple-brown hypodermal pigment of strong and medium intensity. Labial palpi, 6 th and 7 th palpomeres of maxillary palpi and tarsi of all legs without hypodermal pigment. Scale color on surface of body brown with longitudinal darker stripe from metanotum to urotergite IX. Antennae 1.8 times shorter than body. Distal chains of flagellum divided into 5 annuli ( Fig. 2 ). Cerci about 0.32 times body length, with one apical spike.

Compound eyes light bluish (in alcohol). Length to width ratio of compound eye 0.92; ratio of contact line to length of eyes about 0.16. Paired ocelli sublateral, oval, light brown with narrow white borders. Ratios of width to length of ocelli about 2.3. Ratio of distance between inner and outer margins of ocelli to total width of compound eyes, respectively 0.41 and 0.92 ( Fig. 1 ).

Apical palpomere of maxillary palp about 0.90 times length of preceding one; ratio of lengths of 5 th to 4 th palpomeres 1.6. Dorsal surface of 5 th, 6 th and 7 th palpomeres of maxillary palp with 2–3, 12 and 12–13 hyaline spines, respectively. Underside surface of palpomeres 5–7 of maxillary palp as well as of apical palpomere 3 of labial palp with abundant small chaetae ( Figs 3, 5 ). Apical palpomere of labial palp triangularly oval, about 1.6 times longer than wide ( Fig. 3 ). Mandibles with 4 distal teeth ( Fig. 4 ).

Fore femur widened. Ratios of length to width of femur, tibia and tarsus as shown in Table 1. Middle legs shorter than fore and hind legs. Ratio of length of 3 rd tarsomere to total length of tarsus 0.39–0.40. Undersurface of tibiae and tarsi with two rows of spine-like chaetae ( Fig. 6 ). Second tarsomere with more spine-like chaetae than the first and third tarsomeres; number of tibial spine-like chaetae increases from fore to hind tibia; fore femoral projection on underside with 14–16 thickened spine-like chaetae (Table 2). Fore femur with sensory field composed of one irregular row of 5– 6 ramose sensilla ( Fig. 6 ). Morphometric ratios found in the sensory field and femur as follows: LF/WF: 1.61; LSF/WSF: 2.90; LSF/LF: 0.51; WSF/WF: 0.28; d/LF: 0.41; d/LSF: 0.80; d/WSF: 2.34. Middle and hind legs with coxal styli. Ratio of length of styli to width of coxae about 1.2–1.3. Pretarsus with bicolored lateral claws.

Urocoxites I, VI and VII with 1 + 1, II–V with 2 + 2 exsertile vesicles. Posterior angle of urosternites II, III 90°, IV and V 104°, VI 99°, VII 102°, VIII 139°. Length ratios of urosternites, urocoxites and urostyli given in Table 3.

Table 2. Number of spine-like chaetae on the tarsomeres and tibia of the male of Allopsontus agvalensis sp.n. Таблица 2. Количество игловидных Щетинок на члениках лапки и голени самца Allopsontus agvalensis sp.n. Table 3. Length ratios of urosternites, urostyli and urocoxites of the male of Allopsontus agvalensis sp.n. Таблица 3. ОтноШениЯ длин брюШных стернитов, грифельков и кокситов самца Allopsontus agvalensis sp.n. Table 4. Distribution of sublateral macrochaetae on urotergites and urocoxites of the male of Allopsontus agvalensis sp.n.

Таблица 4. Распределение сублатеральных макрохет на тергитах и кокситах брюШка самца Allopsontus agvalensis

sp.n. Table 1. Ratios of length to width of main leg segments of the male of Allopsontus agvalensis sp.n. Таблица 1. ОтноШениЯ длины и Ширины основных сегментов ног самца Allopsontus agvalensis sp.n.

Thoracic tergites, urotergite I, all urosternites and urocoxites I, II and IX without macrochaetae. Distribution of sublateral macrochaetae on urocoxites and urotergites given in Table 4.

Male genitalia with one pair of parameres on urite IX. Parameres with 1 + 5 divisions, not quite attaining apex of penis. Penis and parameres clearly not attaining level of apex of coxites IX ( Fig. 7 ). Length to width ratio of apical portion of penis about 2.3. Apical portion of penis 1.3 times length of basal portion.

Female unknown.

COMPARATIVE REMARKS. Allopsontus agvalensis sp.n., with 2 + 2 exsertile vesicles on urocoxites II–V and without long thin chaetae on male legs, maxillary and labial palpi belongs to the subgenus Allopsontus s. str. Silvestri, 1911, including 19 species. Among these species only A. agvalensis sp.n., A. verae Kaplin, 2015 from South-Eastern Kazakhstan and A. hebraeus ( Wygodzinsky, 1974) from Israel, have abundant small chaetae on the underside surface of palpomeres 5–7 of maxillary palp as well as of apical palpomere 3 of labial palp and the fore femur with narrow sensory field [ Wygodzinsky, 1974; Kaplin, 1993, 2015] in the males only. The main differences between these species are shown in Table 5. The new species differs from A. verae and A. hebraeus in eye color, short eyes contact line, small number of ramose sensilla in male fore femur, longer apical palpomere of the maxillary palp and shorter urostyli of urocoxites IX.

ETYMOLOGY. The new species is named after the Agvali settlement, close to where it was collected.

Table 5. Main morphological differences between males of Allopsontus agvalensis sp.n., A. verae and A. hebraeus . Таблица 5. Основные морфологические раЗличиЯ самцов Allopsontus agvalensis sp.n., A. verae an A. hebraeus .

Acknowledgements. I am grateful to Dr. Graeme B. Smith from Australian Museum Research Institute (Sydney, Australia) for reading and editing the English language text of this paper.

Figures

Figs 1–7. Allopsontus agvalensis sp.n., holotype (male): 1 — anterior part of head (vertex, compound eyes, paired ocelli, frons, antennae bases, median ocellus, clypeus, and labrum); 2 — distal chain of flagellum; 3 — maxillary palpus; 4 — apex of mandible; 5 — labial palpus and labium (part); 6 — fore leg (part); 7 — urocoxite IX with genital appendages. Scale bars: 0.1 mm. Рис. 1–7. Allopsontus agvalensis sp.n., голотип (самец): 1 — переднЯЯ часть головы (Затылок, сложные глаЗа, парные глаЗки, лоб, основаниЯ усиков, медианный глаЗок, наличник и верхнЯЯ губа); 2 — дистальнаЯ цепочка жгутика; 3 — нижнечелюстной Щупик; 4 — апикальнаЯ часть верхней челюсти; 5 — нижнегубной Щупик и нижнЯЯ губа (часть); 6 — переднЯЯ нога (часть); 7 — брюШной коксит IX с половыми придатками. МасШтабные линейки: 0,1 мм.