Allopsontus ilyai Kaplin, 2018

Kaplin, Vladimir, 2018, A new species of the genus Allopsontus Silvestri (Archaeognatha: Machilidae) from the Eastern Kazakhstan, Zootaxa 4500 (4), pp. 508-516 : 509-514

Allopsontus ilyai Kaplin , sp. nov.

Figs. 1–14

Diagnosis. Allopsontus ilyai resembles A. smelyanskii from Orenburg Region ( Russia) in the body length, distribution and intensity of hypodermal pigment, relative length of cerci, line of eyes contact, the ratio of the length of eye to its width, distance between the inner edges of the paired ocelli to the total width of compound eyes, length of the last segment of labial palp to their width, number of segments of the ovipositor in females and parameres in males. However, it can be distinguished from A. smelyanskii by the color of the compound eyes, structure of the paired ocelli, legs, urosternites, and urocoxites VIII and IX.

Description. Body length of two males, 8.8 (holotype), 10.3 (paratype) mm; of female, 10.6 mm; width of males and female 2.2, 2.3 and 2.4 mm, respectively. General body color (in alcohol) brownish, with hypodermal pigment of medium intensity. Labium, labial palp, apical part of clypeus, 6th and 7th articles of maxillary palp, coxal and abdominal styli without pigment. Scale color on dorsal surface of body dark brown to black; ventral surface brownish; strip of white scales around eyes, spot of brown scales on vertex of the head between the eyes. Antennae shorter than body. Distal chains of flagellum divided into five or six annuli. Cerci about 0.32 (holotype male), 0.30 (paratype male), 0.38 (female) times body length; with one apical spike ( Fig. 2 ). Clypeus of males without long thin bristles.

Compound eyes bluish-grey (in alcohol). Ratio length to width of compound eye 1.1 (holotype and paratype males), 1.2 (female); ratio of line of contact to length of eyes 0.32 and 0.30, respectively. Paired ocelli sublateral, light brown with narrow white border, 3.0 (female), 3.4 (holotype) and 3.5 (paratype) (males) times wider than long. Ratio of distance between inner margins of ocelli to total width of compound eyes 0.47 (holotype male), 0.49 (paratype male), 0.45 (female) ( Fig. 1 ).

Apical article of maxillary palp 0.92 (male), 0.83–0.86 (female) times as long as the preceding article; ratio of length of 5th to 4th article 1.47–1.55 (male), 1.58–1.64 (female). Dorsal surface of 5th, 6th and 7th articles of maxillary palp with 2, 11–12 and 12–13 hyaline spines, respectively, in both sexes. Undersurface of articles 5–7 of male maxillary palps with short, adpressed setulae ( Fig. 5 ). Labial palp of male without such setulae. Apical article of labial palp triangularly oval, 2.2–2.3 (male), 2.6–2.7 (female) times longer than wide ( Figs. 7 , 13 ). Mandibles with four distal teeth ( Figs. 6 , 10 ).

Fore femur and fore and middle tibiae of male and female widened ( Table 1). Ratio of length of 3rd tarsomere to total length of tarsus in female 0.36, in male 0.38–0.39. Undersurface of tibiae and tarsi with two rows of spinelike setae ( Figs. 3, 4 , 14 ). Second tarsomere generally with more spinelike setae than the first and third tarsomeres; tibial spinelike setae increasing from fore to hind tibia; fore femoral projection on underside with 24– 28 thickened spinelike setae; male femora on other legs, and all female femora, with few or no such setae ( Table 2). Fore femur of male with narrow, elongated sensory field composed of one irregular row of 14‒15 ramose sensilla ( Fig. 3 ). Morphometric ratios found in the sensory field and femur as follows: LF/WF: 2.25; LSF/WSF: 4.50; LSF/ LF: 0.50; WSF/WF: 0.25; d/LF: 0.40; d/LSF: 0.80; d/WSF: 3.60. Middle and hind legs with coxal styli. Length of styli 0.55–0.60 mm in males, 0.60–0.68 mm in female. Ratio of length of styli to width of middle and hind coxae about 1.4 (female), 1.6 (males). Legs of males without long, thin bristles. Pretarsus with bicolored lateral claws.

Urites I–VII with 1 + 1 eversible vesicles. Posterior angle of urosternites II–VI approximately 100–105 о in both sexes, on urosternite VII 113 о (male) and 140 о (female), on urosternite VIII 148 о. Ratio of length of urostyli to urocoxites on urites II–VII 0.6–07, VIII and IX 0.8–0.9, in both sexes ( Table 3). Apical spines on urostyli short. Ratio of length of apical spines to urostyli (not including spines) on urites II–VIII about 0.18–0.28. Urosternite VIII in male with apical and lateral angles ( Fig. 8 ). Inner posterior lobes of urocoxites VII of female protruding ( Fig. 12 ). Thoracic tergites, urotergites I–II, urosternites, urocoxites I–IV and urocoxite IX without macrochaetae; urotergite VII with 2–3 + 2–3, VIII and IX with 3–4 + 3–4, X with 1 + 1 sublateral macrochaetae ( Table 4).

Ovipositor slender, elongate, significantly surpassing apex of styli IX by about 0.75 times length of the latter ( Fig. 11 ). Length of ovipositor about 3.8–4.5 mm. Anterior and posterior gonapophyses with approximately 73 or 74 divisions, respectively. Anterior gonapophyses with basal 4 divisions, and posterior gonapophyses with basal 25 divisions glabrous. Distal spines of gonapophyses as long as four apical divisions combined.

Male genitalia with one pair of parameres on urite IX. Parameres with 1 + 6 divisions, not quite attaining apex of penis. Penis and parameres attaining level of apex of urocoxites IX ( Fig. 9 ). Length to width ratio of apical portion of penis about 2.0. Apical portion of penis 1.3 times length of basal portion.

Material examined. Holotype male (on slides), Kazakhstan, East Kazakhstan Region: 47°48′N 81°08′E, Ayagoz District, foothills of Tarbagatai, elev. 883 m, semidesert, Artemisia pauciflora – Salsolae association, on the surface of the soil among breakstone. One paratype female (on slides), one paratype male, same locality as holotype, 13.06.2015 (I. È. Smelyanskiy).

Etymology. The new species is named after the collector Ilya Smelyanskiy, a renowned expert in the field of ecology and nature protection from Novosibirsk.

Figures

FIGURES 1–9. Allopsontus ilyai sp. nov., holotype (male). 1. Eyes and paired ocelli, front view; 2. Apex of cercus; 3. Foreleg; 4. Hind tarsus and tibia; 5. Maxillary palp; 6. Distal part of mandible; 7. Labial palp, with part of labium; 8. Urosternite and urocoxites VIII; 9. Urocoxite IX, with genital appendages. Scale bars: 0.1 mm.

FIGURES 10–14. Allopsontus ilyai sp. nov., paratype (female). 10. Distal part of mandible; 11. Urocoxite IX, with anterior gonapophyses; 12. Urosternite and urocoxites VII; 13. Labial palp with part of labium; 14. Foreleg. Scale bars: 0.1 mm.