Typhloiulus opisthonodus Antić, new species

Figs 13, 14, 15C

Material examined: Type specimens. Holotype male, CROATIA, Dalmatia, Stilja, Maršići, Špilja pod Gažnovcem Cave (43.229748°N, 17.314177°E), 28 October 2014, T. Rađa leg. (NHMSC).

Diagnosis. Typhloiulus opisthonodus is most similar to the members of the subgenus Inversotyphlus, viz. T. lobifer, T. gellianae, and herein described T. clavatus, and T. gracilis . These species are characterized by the presence of a very long opisthomere with a similarly shaped velum; the presence of a poorly developed, but visible opisthomeral lamella; and similar other male sexual and habitus structures (see Discussion). The new species differs clearly in the general shape of the promere, which more closely resembles the promere in some other Typhloiulus species, e.g., T. albanicus, T. giganteus, and T. rhodopinus; in the presence of a mesomere with an anterior protuberance; in the presence of an opisthomere with a posterior node; and in the presence of a less developed ventral margin of body ring seven.

Description. Based on holotype (male) 28 mm long, vertical diameter of the largest body ring 1.7 mm, body with 48 podous rings + 1 apodous ring + telson. Colouration: (Fig. 13A). Depigmented, yellowish-brown. Head: (Fig. 13B). Labrum with three labral teeth, with 4 supralabral and 5+6 labral setae. Gnathochilarium with promentum kite-shaped, elongated; lamellae linguales 4+ 4 in one row; stipites each with 4 setae. Antennae 2.3 mm long, length 135% of vertical diameter of the largest body ring. Length of antennomeres I–VIII (in mm): 0.16 (I), 0.46 (II), 0.45 (III), 0.35 (IV), 0.43 (V), 0.28 (VI), 0.12 (VII), and 0.05 (VIII). Length/width ratio of antennomeres I–VII: 1 (I), 2.9 (II), 2.8 (III), 2 (IV), 2 (V), 1.4 (VI), and 0.8 (VII). Antennomeres V and VI each with a terminal corolla of large bacilliform sensilla; antennomere VII with a terminal corolla of microsetae. Body rings: (Fig. 13D). The entire metazonal area with longitudinal striations. Midbody rings with ca. 20 short metazonal setae. Length of midbody setae ca. 13% of vertical diameter of rings. Telson: (Fig. 13E). Epiproct with a long preanal process, strongly curved downwards and covered by long dorsal and lateral setae. Paraprocts rounded, with numerous long setae. Hypoproct lenticular, with 5 long setae. Legs: First pair of legs modified, hook-shaped (Fig. 14A); coxa, postfemur, and tibiotarsus each with one seta, prefemur with five or six setae, femur with two or three setae; tibiotarsus with small tarsal remnants in the form of a dorsal lobe. The tip of the first pair of legs tuberculate. Second pair of legs with poorly developed ventral pads on the tibia. Penis: (Fig. 14B). Bilobed. Lobes prominent, elongated. Ventral margin of body ring 7: (Fig. 13C). Developed, with a somewhat rounded postero-ventral part. Gonopods: (Figs 14C–F, 15C). Slender and elongated. Promere (p) and mesomere (m) considerably shorter than opisthomere (o). Promere slightly longer than m; laterally in the form of a shield, with postero-mesal concavity for m accommodation; mesal lobe (ml) wide, subquadrangular, with four apical setae; telopodite (t) well-developed, subcylindrical, tapering distad, shorter than ml. Mesomere (m) slender; antero-apical part rounded and tuberculated; with anterior protuberance on half of its length. Opisthomere (o) slender, straight and elongated; antero-mesally with poorly developed lamella (l); posteriorly with well-developed node (n); mesally with one spine; velum (v) unipartite, well-developed, tapering anteriad, with fimbriated tip. Solenomere (s) rather wide, distally with several short spines.

Distribution. This species is known only from its type locality, Špilja pod Gažnovcem Cave, Stilja (Fig. 20, blue circle).

Notes. Špilja pod Gažnovcem Cave is a small cave, some 40 m long, near the surface with a lot of decomposing material. The fauna of this cave is very rich, especially the millipede fauna. The following taxa have been recorded in the cave: Thaumastocephalu s sp., Bryaxis scapularis (Reitter, 1881), Speonesiotes sp., Phaneropella (Phaneropella) lesinae (Reitter, 1881), and Neotrechus sp. (all Coleoptera); Trirhacus cf. biokovensis Dlabola, 1971 ( Hemiptera); Cyphopthalmus sp. (Opiliones); and Typhloglomeris sp., Apfelbeckia insculpta (L. Koch, 1867), Dyocerasoma biokovense Mršić, 1986, Macrochaetosoma troglomontanum Absolon & Lang, 1933 (Antić et al. 2016), Brachydesmus lapadensis Verhoeff, 1897, B. lobifer Verhoeff, 1897, B. subterraneus Heller, 1858, Metonomastus albus (Verhoeff, 1901), and Stosatea iadrense (Pregl, 1883) (all Diplopoda).

Etymology. To denote the presence of a small node on the posterior side of the opisthomere. Adjective.