Stygiiulus montellensis ( Verhoeff, 1930 ) Vagalinski & Borissov & Bobeva & Canciani & Antić, 2022

Vagalinski, Boyan, Borissov, Simeon, Bobeva, Aneliya, Canciani, Giacomo & Antić, Dragan Ž., 2022, The mostly cavernicolous millipede genus Stygiiulus Verhoeff, 1929, stat. nov.: taxonomy, distribution and phylogenetic relationships (Diplopoda, Julida, Julidae), European Journal of Taxonomy 798, pp. 30-69 : 49

Stygiiulus montellensis ( Verhoeff, 1930) comb. nov.

Figs 7 , 13

Typhloiulus (Stygiiulus) montellensis Verhoeff, 1930: 14–16 , figs 4–5.

Typhloiulus (Stygiiulus) montellensis – Manfredi 1932: 81. — Strasser 1962: 57–58, figs 5, 11j, 66–67.

Typhloiulus montellensis – Wolf 1934 –38: 516. — Vagalinski et al. 2015: 343 .

Typhloiulus montebellensis (sic!) – Attems 1949: 145.

Typhloiulus (Stygiiulus) montellensis montellensis – Paoletti 1978: 108.

Typhloiulus montellensis montellensis – Minelli 1985: 10.

Diagnosis

A species of Stygiiulus stat. nov. with normal mouthparts. Differs from its most similar congener, S. rotundatus comb. et stat. nov., by the distal part of mesomere ( Fig. 7B, m in Fig. 7A ) being clavate, ending with a broad, flat apex, vs the same being fronto-caudally compressed, ending with a rounded apex in the latter species; and by the vulval operculum being broader and with a smooth and gently concave apical margin, vs the same being relatively narrow, with an uneven, coarsed/undulating apical margin in S. rotundatus comb. et stat. nov.

Material examined

ITALY • 3 ♂♂, 4 ♀♀; Veneto, province of Treviso, Susegana, Grotta [cave] Crede-a (2098 V / TV); 175 m a.s.l.; 20 Feb. 1993; E. Piva leg.; NHMD • 2 ♂♂, 1 ♀, 1 juv.; Veneto, province of Treviso, Massiccio del Grappa Mtn, Cavaso del Tomba , Speoncia [cave] del Diaol (1811 V /TV); 45°50'49'' N, 11°54'26.4'' E; 275 m a.s.l.; 17 Oct. 1999; E. Piva leg.; NHMD .

Descrptive notes

ANTENNAE. 1.85–2.2 times as long as head and 1.5–2.1 times as long as H in males, and 2–2.1 and 1.3– 1.5 times, respectively, in females; antennomere 5 2–2.3 times as long as broad; antennomeres 2 and 3 subequal in length, 1.1–1.2 times as long as 4 and 5, and 1.2–1.4 times as long as 6. Tarsus of mid-body legs 2–2.3 times as long as tibia and 3–4 times as long as apical claw. Mid-body legs from equal to, to 1.4 times as long as, H in males, and 0.9–1.1 times in females.

FEMALE SEXUAL CHARACTERS. Legs 1 and 2 slightly shorter but not thicker than following legs. Vulva ( Fig. 7C ) symmetric, somewhat compressed in the sagittal plane; bursa with a rather broad cleft, each valve distally with several setae in a vertical row; operculum (op) large, subquadrangular, with a slightly convex, smooth apical margin, exceeding bursa by ca ⅓ of total height of vulva, distally with several setae each side. Receptaculum seminis represented by a relatively long, narrow, slightly bent, mesal tube (mt) leading to a minute piriform ampulla (ma), and an even finer, shorter, twisted, lateral tube (lt) forming an ovoid ampulla (la) at bottom.

Distribution

Known from several caves as well as epigean habitats in a small area on the southern side of the Venetian Prealps’ foothill, north of Treviso.All but one record come from the right side of the Piave River ( Fig. 13 , yellow squares).

Figures

Fig. 7. Stygiiulus montellensis (Verhoeff, 1930) comb. nov., ♂ from Grotta [cave] Crede-a (NHMD). A. Right gonopods, mesal view. B. Right mesomere, oral view. C. Left vulva, caudal, slightly mesal view. Abbreviations: la = lateral ampulla; lt = lateral tube; m = mesomere; ma = median ampulla; mt = median tube; op = operculum. Scale bars: A–B = 0.2 mm; C = 0.3 mm.

Fig. 13. General distribution of the species of the genus Stygiiulus stat. nov.