Stygiiulus tobias (Berlese, 1886) 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 : 55-57

Stygiiulus tobias (Berlese, 1886) comb. nov.

Figs 10F , 11D , 13

Julus (Typhloiulus) Tobias Berlese, 1886: 98–99 , tab. XIII, figs 20–23.

Typhloiulus (Iulus, Mesoporoiulus) Tobia (tobias ) – Manfredi 1932: 81.

Typhloiulus tobias – Wolf 1934 –38: 516. — Vagalinski et al. 2015: 345–346 .

Typhloiulis (sic!) tobias – Boldori 1936: 113.

Typhloiulus Tobia (sic!) – Boldori 1937: 11.

Typhloiulus (Mesoporoiulus) tobias – Verhoeff 1930: 16–17, fig. 3. — Strasser 1962: 38–39, figs 11f, 45–46.

Typhloiulus Tobias – Conci 1951: 44.

Typhloiulus tobias var. fuscus Manfredi, 1953a: 139 .

? Typhloiulus tobias pygmaeus Manfredi, 1953b: 100 .

Typhloiulus tobias fuscus – Manfredi 1953b: 101.

Diagnosis

A species of Stygiiulus stat. nov. with normal mouthparts. Clearly distinguishable from congeners by the very distinctive structure of the opisthomere ( Fig. 10F ) including a right- to acute-angled posterior hump pointing distad, a large, (sometimes) bipartite velum (with a posteriorly positioned distal outgrowth (do), this being much less prominent than in S. insularis comb. nov. and S. seewaldi comb. nov.), with the main part being mostly smooth (barely serrated), and a solenomere distally forming a stout anterior and a much more slender posterior branch, both apically finely ciliate; some specimens with a minute third thumb-like branch basally to the posterior branch. In addition, this species (except for its dubious subspecies T. t. pygmaeus, see below) differs from all other Stygiiulus stat. nov. species by the presence of a very long and upwards curved epiproct.

Material examined

ITALY • 2 ♂♂, 1 ♀; Veneto, Altopiano dei Sette Comuni , Vastagna (VI), Grotta [cave] del Subiolo (135 V/VI); 169 m a.s.l.; 4 Mar. 1990; G. Peretto and E. Piva leg.; H. Enghoff det. 2013; NHMD .

Descriptive notes

ANTENNAE. 2.2–2.4 times as long as head and 1.65–1.7 as long as H in males, and 1.9–2 and 1.3– 1.4 times, respectively, in females; antennomere 5 2.6–2.9 times as long as broad; antennomeres 2, 3 and 5 subequal in length, slightly longer than 4, and 1.4–1.5 times as long as 6.

TARSUS OF MID- BODY LEGS. 1.8–1.9 times as long as tibia and 2.8–4.3 times as long as apical claw. Midbody legs ca 1.25 times as long as H in males, and equal in length in females.

FEMALE SEXUAL CHARACTERS. Leg-pairs 1 and 2 considerably thicker and shorter than following legs. Vulva ( Fig. 11D ) nearly symmetric; bursa slightly compressed in the sagittal plane; each valve distally with one vertical row of several setae; a similar row present on each side sclerite; operculum (op) very thick, subconical, i.e., tapering to a distinct blunt apex, exceeding bursa by ca 1 ⁄ 5 of total height of vulva, distally with a dense bunch of setae each side. Receptaculum seminis consisting of two long and narrow, closely adjacent tubes of equal length – a twisted lateral one (lt) leading to a small piriform ampulla (la), and a mostly straight mesal one (mt) ending in a somewhat larger ovoid ampulla (ma).

Distribution

Known from numerous caves and one epigean locality in the central Venetian Prealps, as well as from several caves in Monti Lessini (extreme south of the Venetian Prealps). Also known from two caves on the southern slopes of Dolomiti ( Fig. 13 , white squares).

Remarks

In the past, this taxon was treated as a member of Mesoporoiulus Verhoeff, 1905 . Vagalinski et al. (2015) hypothesized it could be a somewhat deviating member of Stygiiulus . Here we fully confirm this assumption and formally transfer tobias to the genus Stygiiulus .

The subspecies S. t. pygmaeus (Manfredi, 1953) comb. nov. has already caught the attention of Strasser (1962). On page 60 of the latter work, the author commented on the significant size difference between pygmaeus (23 mm of length) and the typical tobias (50–67 mm of length), and also emphasized the apparent confusion of Manfredi (1953b) regarding the gonopods of her newly described subspecies, which she stated to match well (along with most other characters) to the descriptions of tobias given by both Attems (1927) and Verhoeff (1930). In fact, what Attems (1927) recorded and depicted was S. maximus comb. nov. (see Remark under the latter species). The short and straight epiproct in pygmaeus (as originally described), unlike the long and upwards curved process in the typical form, adds further uncertainty about the identity of Manfredi’s subspecies. We agree with Strasser’s (1962) opinion that pygmaeus most likely represents a separate species. However, its status can only be resolved after examination of type or topotype material.

The gonopods of the two presently examined males from Grotta del Subiolo differ fromVerhoeff’s(1930) drawings based on material from Grotta Parolini near Vastagna and/or “Bus de la Bela” near San Donato, prov. Belluno, by a blunt and finely serrated, rather than tapering and ciliate, posterior part of velum, and by an apically tri- instead of bipartite solenomere.

In Grotta della Bigonda, this species lives in sympatry with S. ausugi comb. nov.

Figures

Fig. 10. Left gonopods of species of Stygiiulus stat. nov., mesal views. A. S. ausugi (Manfredi, 1953) comb.nov.,topotype♂(NHMD).B.S.illyricus(Verhoeff,1929)comb.nov.,redrawnfromVerhoeff (1929). C. S. insularis (Strasser, 1938) comb. nov., redrawn from Antić et al. (2018). D. S. maximus (Verhoeff, 1929) comb. nov., redrawn from Verhoeff (1930). E. S. seewaldi (Strasser, 1967) comb. nov., redrawn and modified from Strasser (1967). F. S. tobias (Berlese, 1886) comb. nov., ♂ from Grotta [Cave] del Subiolo (NHMD). Abbreviations: do = distal outgrowth of velum. Drawn not to scale.

Fig. 11. Left vulvae of species of Stygiiulus stat. nov. (A–D) and representatives of (other) Julini/ Leptoiulini (E) and Typhloiulini/blind Julini/Leptoiulini in caudal, somewhat mesal views. A. S. ausugi (Manfredi, 1953) comb. nov., ♀ from Grotta [Cave] del Calgeron (NHMD). B. S. illyricus (Verhoef, 1929) comb. nov., ♀ from Rabakova Cave (IZB). C. S. insularis (Strasser, 1938) comb. nov., topotype ♀ (CBSS). D. S. tobias (Berlese, 1886) comb. nov., ♀ from Grotta [Cave] del Subiolo (NHMD). E. Leptoiulus cf. trilineatus(C.L. Koch, 1847), ♀ from Belasitsa Mtn, Bulgaria. F. Serboiulus spelaeophilus Gulička, 1967, ♀ from Vodni Pech Cave (NMNHS). G. Typhloiulus (Inversotyphlus) lobifer Attems, 1951, ♀ from Minjera-Bauxite Mine (IBER). H. Typhloiulus (s. str.) strictus (Latzel, 1882), ♀ from Kunino (IBER). Abbreviations: at = anterior tube; la = lateral ampulla; lt = lateral tube; ma = median ampulla; mt = median tube; op = operculum; pa = posterior ampulla; pt = posterior tube. Scale bar = 0.2 mm.

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