A NEW SPECIES OF THE BRISTLETAIL GENUS MACHILINUS SILVESTRI, 1905 (MICROCORYPHIA: MEINERTELLIDAE) FROM CRIMEA Author Kaplin, V. G. Author Martynov, V. V. text Far Eastern Entomologist 2024 2024-09-30 508 19 26 https://doi.org/10.25221/fee.508.2 journal article 10.25221/fee.508.2 2713-2196 14658685 452B763F-CBC8-483C-B790-F6DA88F784E1 Machilinus ( Machilinus ) crimaeus Kaplin , sp. n. https://zoobank.org/NomenclaturalActs/ 7C5B7C94-EFE8-4DEE-9886-2F79412A7CBF Figs 1–16 Figs 1–11. Machilinus crimaeus Kaplin , sp. n. , holotype ♂ (1–5, 7–11) and paratype ♀ (6). 1 – distal chain of flagellum; 2 – apex of mandible; 3 – compound eyes, ocelli, clypeus and upper lip; 4 – maxillary palpus; 5, 6 – labial palpus; 7 – tarsus, tibia, femur and trochanter of fore leg; 8 – tarsus and tibia of hind leg; 9 – pronotum; 10 – mesonotum; 11 – metanotum. Scale bars = 0.1 mm. MATERIAL. Holotype : male (slide mounted, VIZR ), Russia : Crimea , Leninsky district , near the village Osoviny , 45°26'N , 36°36'E , h~ 65 m , petrophytic steppe, shell rock scree, under stones, 17.VI 2022 (leg. V . V . Martynov). Paratypes : 7 ♂ , 14 ♀ ( 1♂ , 2 ♀ in slides), ( VIZR ), the same locality and date (leg. V . V . Martynov) . Figs 12–16. Machilinus crimaeus Kaplin , sp. n. , holotype ♂ (16) and paratype ♀ (12– 15). 12 – urosternite and urocoxites VII; 13 – urocoxites VIII and IX with gonapophyses; 14 – distal part of anterior gonapophyse; 15 – distal part of posterior gonapophyse; 16 – urocoxite IX, with penis. Scale bars = 0.1 mm. DESCRIPTION. Body length: male 5.8–7.0 mm, female 6.8–7.5 mm . Body width: male 1.8–2.0 mm, female 1.9–2.2 mm . Antennal length: 3.2–4.0 mm in male, 3.2–4.3 mm in female (broken); cercal length 1.8–2.2 mm in male, 2.1–2.3 mm in female; total eyes width: 0.66–0.77 mm in male, 0.66–0.80 mm in female; eye length: 0.37–0.46 mm in male, 0.40– 0.47 mm in female; paired ocelli width: 0.16–0.17 mm in both sexes; paired ocelli length: 0.09–0.10 mm in both sexes. Ovipositor length 2.2–2.9 mm . Thoracic coxal styli absent. Head including antennae, maxillary and labial palpi, clypeus, labrum, labium, and legs without scales; rest of body with scales. The scales are brownish and brown, darker on underside of body. Table 1. Ratios of lengths to widths of main leg articles in Machilinus crimaeus sp. n. Leg articles and Pair of legs sex fore middle hind Tarsus male 4.85 4.50 5.21 female 4.78 4.08 5.45 Tibia male 1.96 2.34 3.38 female 1.81 1.90 3.50 Femur male 2.06 2.40 2.85 female 1.87 2.18 2.60 Coxa male 2.29 2.43 2.57 female 2.19 2.37 2.57 Table 2. Number of spines on legs in Machilinus crimaeus sp. n. Pair of legs Segments and sex fore middle hind 1st male 4 5–6 9 2nd 10 8–10 10–12 3rd 8 8 8 Tarsomeres 1st female 5 5 8 2nd 9–10 8 10 3rd 6–8 6 8 Tibia male 7 6–7 14 female 8 8–9 14 Femur male 7 10–14 9– 10 female 8 7 8-9 General body color light whitish. Areas of head around eyes, ocelli, antennae, labrum, labium, mandibles, maxillae, legs, dorsal part of thorax and abdomen with a brownish-violet pigment of predominantly weak and medium intensity. Ratio of length to width of scapus about 1.7 in male and 1.7–1.8 in female. Antennae in both sexes shorter than body. Apices of cerci with 2 easily breakable supporting spines: one well developed and the other considerable smaller. Distal chains of flagellum with 8 or 9 annuli ( Fig. 1 ). Two or three distal chains of antennal flagellum broken. Apices of mandibles 4-lobed ( Fig. 2 ). Eyes in alcohol dark, with bluish tint without spots. Ratio of length to width of compound eye about 1.1–1.2 in both sexes; ratio of contact line length to eye length 0.64–0.66 in both sexes. Paired ocelli oval, sublateral, white with narrow border; 1.6–1.7 times as wide as long in male and in female ( Fig. 3 ). Distance between inner margins of ocelli 0.58–0.60 and between their outer margins 0.92–0.95 times total width of compound eyes, in both sexes. Clypeus of male with black, relatively numerous short simple setae, slightly longer and less numerous on frons. Cercus approximately 0.26–0.30 times as long as body length in male and 0.28–0.32 times in female. Cerci with 9–10 clear articles and 18–20 articles with clear and unclear boundaries between them in male and in female with two or four rows of scales. Articles of cerci, except for apical one, with two rows, including 1–3 supporting spines on inner side. In male, 12–14 rows of articles with indistinct boundaries from the base of the cerci also with 1–3 supporting spines on ventral side. Table 3. Ratios of lengths of some abdominal structures in Machilinus crimaeus sp. n.

Urites	Urosternite / urocoxite		Stylus / urocoxite		Apical spine / stylus
	male	female	male	female	male	female
II	0.20	0.21	0.58	0.51	0.37	0.40
III	0.19	0.19	0.52	0.48	0.33	0.42
IV	0.18	0.20	0.49	0.49	0.35	0.44
V	0.15	0.15	0.46	0.46	0.36	0.43
VI	0.16	0.14	0.45	0.45	0.37	0.43
VII	0.11	0.12	0.46	0.48	0.36	0.43
VIII	0.10	-	0.57	0.70	0.33	0.42
IX	-	-	0.64	0.74	0.26	0.25

Remark. Apical spines are not included in stylus length. Table 4. Distribution of sublateral mesochaetae and relatively thin chaetae on urocoxites in Machilinus crimaeus sp. n.

Urites	Male	Urocoxites Female
I	≈ (16–20 + 16–20)	≈ (18–26 + 18–26)
II	≈ (14–22 + 14–22)	≈ (15–18 + 15–18)
III	≈ (14–20 + 14–20)	≈ (14–16 + 14–16)
IV	≈ (10–12 + 10–12)	≈ (15–20 + 15–20)
V	5–8 + 5–8	9–10 + 9–10
VI	4–6 + 4–6	6–9 + 6–9
VII	2 + 2	2–3 + 2–3
VIII	3 + 3	2 + 2
IX	(121 + 92) + (161 + 52)	[(5* + 12–13)1 + 10–112] + [(5–7* + 4–5)1 + 8–92]

Remark. Relatively short thickened pigmented* and more thing and long posterior chaetae near stylus 1 and chaetae in main part of urocoxites IX 2 . Apical article of maxillary palpus of male 0.68 and female 0.64 times as long as preceding one ( Fig. 4 ). Dorsal surface of 7th, 6th and 5th articles of maxillary palpus with 8–10, 8–10, and 2–3 hyaline spines in male, and 8–10, 12 and 3 spines with darkened tops in female, respectively. 5th article of maxillary palpus 1.4 times as long as 4th article in male and in female. Second article of male maxillary palpus noticeably curved with external lateral apical apophysis, which absent in female maxillary palpus. Apophysis surpassing distal end of 2nd article. Outer side of apophysis with about 12–16 dark, almost black, thickened, noticeably curved setae of medium length, without needle-like spines. Inner part of second article with many relatively long, weakly pigmented setae and very small setae on its ventral surface. Shortened third article of male maxillary palp with many relatively evenly distributed darkened, thickened and elongated setae, absent on 3rd article of female maxillary palp. Third article of maxillary palps shorter than its fourth article 1.4–1.5 times in male and 1.5–1.6 times in female. Ventral surface of 1st, 2nd and 3rd articles of male maxillary palp with numerous relatively long thickened setae. The last article of labial palp elongated-oval, with 21–25 apical sensory cones in male and 18–20 in female. Its length in males and females 3.5 times greater than width ( Figs. 5, 6 ). Fore and middle tibia of male and female widened ( Fig. 7 ). Ratios of their lengths to widths 1.8–2.3 as shown in Table 1 . Ratio of length of 3rd tarsomere to total length of tarsus 0.36– 0.37 in male and in female ( Fig. 8 ). Middle legs shortest. Ratio of total length of middle and hind legs to length of fore leg 0.90 and 1.08 in males, respectively, and 0.98 and 1.13 in females. Ventral surface of femora, tibiae and tarsi with spines as shown in Table 2 . Pronotum with deep notch in both sexes as shown in Fig. 9 . Inner margins of its lateral expansions with about 10–22 + 10–22 macrochaetae in male and in female. Lateral margins of mesonotum with 50–52 + 50–52 metanotum with 20–25 + 20–25 macrochaetae in both sexes ( Fig. 10, 11 ). Lateral parts of pronotum also with 8–12 + 8–12, meso- and metanotum with 30–40 + 30–40 macrochaetae long and thin chaetae in both sexes. Near macrochaetae along lateral margins in anterior part of metanotum in male and in female 4–5 long sensory setae. Single long sensory setae also found in posterior parts of metanotum, significantly spaced from lateral margins. Abdominal tergites without macrochaetae. In both sexes, abdominal segments II–VII with 1 + 1 eversible vesicles. Posterior angle of urosternites about 120–160°. Ratios of lengths of urosternite, urocoxite and stylus (without apical spine) on urites II–IX as shown in Table 3 . Inner posterior lobes of urocoxites VII of female protruding; ratio of length to their total width about 0.44 ( Fig. 12 ). Anterior part of urocoxites I with 16–20 + 16–20 chaetae in male and with 18–26 + 18–26 chaetae in female. External posterior part of urocoxites II–VIII near styli with relatively thin setae of medium length. Their number as shown in table 4. Urocoxites IX near the styli in males and in females with setae. Among them, in female 5–7 setae near the styli noticeably thickened and pigmented ( Fig. 13 ). Typical needle-shaped spines not found on urocoxites in male and in female. Ovipositor slender, elongate, extending much further than apex of styli IX. Length of ovipostor 2.2–2.4 mm . Anterior and posterior gonapophyses with 61–63 and 66–68 divisions, respectively. About 28 basal divisions of anterior gonapophyses and 45 proximal divisions of posterior gonapophyses glabrous. Apical spines of gonapophyses as long as 3.0 apical divisions combined. Distal divisions of anterior and posterior gonapophyses with long chaetae as shown in Figs 14, 15 . Male genitalia without parameres. Penis significantly does not attain the apex of urocoxites IX ( Fig. 16 ). Ratio of lengths of apical and basal divisions of penis about 1.0. DIFFERENTIAL DIAGNOSIS. In Machilinus caucasicus , M. obscurus , M. petrophilus , M. priazoivicus , and M. crimaeus sp. n. second article of maxillary palp with well-developed apical apophysis protruding beyond apex of this article. In male of M. petrophilus ventral part of apophysis and adjacent part of 2nd article with about 12–16 dark almost black, short spiniform chaetae (spines). 3rd article of male maxillary palpus also with about 25 almost black short lateral spines. In males of M. obscurus , M. priazovicus and M. crimaeus sp. n. outer side of apophysis with about 12–15 dark lateral chaetae and several longer simple chaetae in upper part of apophysis, without spiniform chaetae. 3rd article of male maxillary palpus with numerous dark brown relatively long thick chaetae, without spines ( Kaplin, 2007 ; Kaplin & Martynov, 2020 , 2022a ). The main morphological differences between M. crimaeus sp. n. and its closest congeners are shown in Table 5 . First of all, new species differs from its closest congeners by color, ratios of length to width, contact line length to length of compound eyes, distance between inner margins of paired ocelli to total width of eyes. DISTRIBUTION. Russia (Crimea). ETYMOLOGY. The new species is named after the type locality.