The mostly cavernicolous millipede genus Stygiiulus Verhoeff, 1929, stat. nov.: taxonomy, distribution and phylogenetic relationships (Diplopoda, Julida, Julidae) Author Vagalinski, Boyan CF6A5691-5C32-4CFF-9EB6-045DEB16F289 Institute of Biodiversity and Ecosystem Research, Bulgarian Academy of Sciences, 2 Gagarin Street, 1113, Sofia, Bulgaria. boyanv84@gmail.com Author Borissov, Simeon C035E1AC-D4FB-4A3F-8B38-5D38A9665E88 Institute of Biodiversity and Ecosystem Research, Bulgarian Academy of Sciences, 2 Gagarin Street, 1113, Sofia, Bulgaria. borissovsb@gmail.com Author Bobeva, Aneliya 0F4EA315-46BE-49AC-8FB4-CF710C5B2451 Institute of Biodiversity and Ecosystem Research, Bulgarian Academy of Sciences, 2 Gagarin Street, 1113, Sofia, Bulgaria. aneliabobeva@gmail.com Author Canciani, Giacomo 4BB21FD2-15C8-44BD-907A-4498D7D02A15 Jamarski Klub Kraški Krti / G. S. Talpe del Carso, loc. San Michele del Carso / Vrh, I- 34070 Savogna d’Isonzo (GO), Italy. & Associazione Speleologica Forum Julii Speleo, Via Carraria 99, I- 33043 Cividale del Friuli (UD), Italy. giacomo.canciani90@gmail.com Author Antić, Dragan Ž. 2368C980-2042-4137-998D-8C91E4337185 University of Belgrade - Faculty of Biology, Institute of Zoology, Studentski Trg 16, 11000 Belgrade, Serbia. & Serbian Biospeleological Society, Trg Dositeja Obradovića 2, 21000 Novi Sad, Serbia. dragan.antic@bio.bg.ac.rs text European Journal of Taxonomy 2022 2022-02-28 798 30 69 http://dx.doi.org/10.5852/ejt.2022.798.1669 journal article 20422 10.5852/ejt.2022.798.1669 31fec661-5dac-4626-856d-4ba4680efee7 2118-9773 6323002 50692D26-A41C-4F85-B207-A6747FD07470 Stygiiulus ausugi (Manfredi, 1953) comb. nov. Figs 10A , 11A , 13 Typhloiulus ausugi Manfredi, 1953b: 136–138 , figs 1–2. Typhloiulus ( Stygiiulus ) ausugi – Strasser 1962: 11 , 12, 18, 37, 38, figs 1–2, 8, 11h, 15, 41–44. Typhloiulus ( Stygiiulus ) ausugi ausugi – Strasser 1971a: 13 . Typhloiulus ausugi ausugi – Minelli 1985: 9 . Typhloiulus ausugi – Vagalinski et al. 2015: 336–337 . Diagnosis One of the three species of Stygiiulus stat. nov. with modified mouthparts, the other two being S. fimbriatus comb. et stat. nov. and S. gentianae comb. et stat. nov. Differs from both mainly by the complete absence of posterior hump on opisthomere, the very large velum with minute fringes on posterodistal margin, and the anterior and posterior solenomeral branches both being very short, hardly distinguishable. Material examined ITALY – Trentino ( Autonomous Province of Trento ) • 1 ♂ ; topotype; Altopiano dei Sette Comuni , Grigno , Grotta [Cave] della Bigonda (243 VT/TN); 450 m a.s.l. ; 10 Mar. 1996 ; G. Peretto and E. Piva leg.; H. Enghoff det. 2013; NHMD • 1 ♀ ; Grigno , Grotta [Cave] del Calgeron (new record), a side branch of the waterfall ; Dec. 1973 ; Ischia leg.; H. Enghoff det. 1984; A. Minelli ded. 1985; NHMD . Descriptive notes ANTENNAE. 2–2.1 times as long as head and 1.7–1.75 times as long as H in males, and 1.7–1.8 times and ca 1.4 times, respectively, in females; antennomere 5 ca twice as long as broad; antennomeres 2, 3 and 4 subequal in length, ca 1.2 times as long as 5, and 1.7–1.8 times as long as 6; 6 visibly broader than 5, giving a clavate appearance of the antenna. MOUTHPARTS. With strong hydrophilous modifications (sensu Enghoff 1985 ): labrum edentate or with three minute, vestigial teeth. Gnathochilarium short and distally markedly broad, stipites with conspicuously large palps. Gnathal lobes of mandibles with the external and the internal tooth strongly reduced, both being distinct but very small and pointed, deeply hidden in the buccal cavity; molar plate much smaller than the normal julid condition; pectinate lamellae five instead of the usual four, consisting of very fine and densely set teeth. TARSUS OF MID- BODY LEGS. Ca 2.5 times as long as tibia and ca 5 times as long as apical claw. Mid-body legs ca 1.7 times as long as H in males and ca 1.4 times in females. FEMALE SEXUAL CHARACTERS. Legs 1 and 2 slightly shorter but not thicker than following legs. Vulva ( Fig. 11A ) symmetric; bursa very broad, strongly compressed in the sagittal plane; each valve of bursa with one vertical row of setae; operculum (op) distally bulging, with a distinct apical concavity, exceeding bursa by nearly ⅓ of total height of vulva, with just several setae each side. Receptaculum seminis consisting of two small tubes: a very fine, somewhat bent, mesal one (mt) ending in a small ovoid ampulla (ma), and a significantly broader, mostly straight, lateral one (lt), not forming ampulla at bottom. Distribution Prior to this study, the species was known only from its type locality – the Grotta della Bigonda – on the northern border of the central part of the Venetian Prealps. The new locality of this species – the Grotta del Calgeron – is located in the same area, some 20 km south of the type locality ( Fig. 13 , blue circles). Remarks Strasser (1971a) described two subspecies of ausugi , viz., fimbriatus and gentianae . Considering the gonopod conformations of the two latter forms, both of which differ significantly from S. ausugi comb. nov. and are instead much more similar to S. illyricus comb. nov. , S. maximus comb. nov. , S. montellensis comb. nov. , and S. rotundatus comb. et stat. nov. , it becomes obvious that Strasser (1971a) treated the modified mouthparts as a taxonomic feature of primary importance, being unaware of the adaptive nature of such modifications, as revealed later by Enghoff (1985) . Thus we here elevate fimbriatus and gentianae to the species level and describe both of them in detail below. In the Grotta della Bigonda, this species lives in sympatry with S. tobias comb. nov.