Typhloiulus parvulus Antić and Dražina, new species

Figs 16, 17, 18E

Material examined: Type specimens. Holotype male, CROATIA, Popovići, Gruda, Konavle, Tunnel Konavosko Polje–sea, Kaverna 781 Cavern, (42.526300N °, 18.338153°), 30 August 2014, R. Ozimec leg. (CNHM) . Paratypes: 1 male (IZB), same data as for holotype; 8 males, 1 female, same data as for holotype except: 21 September 2014, T. Dražina leg. (1 male IZB, rest CNHM); 3 males, 1 female, 1 juvenile, same data as fot holotype except: 30 October 2016, M. Pavlek leg. (CBSS) . Non-type material: 1 male, Mala Đatlo Cave, Korita, near Gacko, Bosnia & Herzegovina, 14 July 2013, T. Rađa leg. (IZB).

Diagnosis. The new species differs from all other Typhloiulus species in the presence of a strongly developed intermediate lamella completely coalesced anteriorly with the mesomere, both continuing proximad as a unified structure (Fig. 17C, D). Also, together with T. insularis, this is the smallest Typhloiulus species.

Description. Based on holotype (male) 12 mm long, vertical diameter of the largest body ring 0.65 mm, body with 43 podous rings + 1 apodous ring + telson. Colouration: (Fig. 16A, 18E). Depigmented, yellowish-white to brownish-yellow. Head: (Fig. 16B). Labrum with three labral teeth, with 4 supralabral and 6+6 labral setae in paratype male. Gnathochilarium with promentum kite-shaped, elongated; lamellae linguales with 1+3 setae, stipites with 3+3 long apical setae and 4+2 short medial setae in paratype male. Antennae 1.1 mm long in holotype male, length 170% of vertical diameter of the largest body ring. Length of antennomeres I–VIII (in mm): 0.07 (I), 0.22 (II), 0.19 (III), 0.18 (IV), 0.2 (V), 0.13 (VI), 0.08 (VII), and 0.03 (VIII). Length/width ratio of antennomeres I–VII: 0.9 (I), 2.5 (II), 2 (III), 2.3 (IV), 1.7 (V), 1.3 (VI), and 1.1 (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. 16D). Smooth. Midbody rings with ca. 10 short metazonal setae. Length of midbody setae ca. 10% of vertical diameter of rings. Telson: (Fig. 16E). Epiproct densely setose, with a short, acuminate preanal process, this being triangular in dorsal view. Paraprocts rounded, with numerous long setae. Hypoproct subrounded, with 1+1 long apical setae. Legs: First pair of legs modified, hook-shaped (Fig. 17A); only three podomeres visible: coxa each with one seta; prefemur each with three setae; femur, postfemur, and tibiotarsus coalesced, with three setae. The tips without tubercules. Second pair of legs without vental pads. Penis: (Fig. 17B). Bilobed. Lobes short. Ventral margin of body ring 7: (Fig. 16C). Poorly-developed, rounded. Gonopods: (Fig. 17C–E). Unusual. Promere (p) higher than mesomere (m). Apical, mesal margin denticulated, lateral margin tuberculated. Mesal lobe (ml) with one seta. Telopodite (t) very small, rounded, hardly visible. Mesomere (m) subapically with an anterior tuberculated lobe. Posteriorly basal half fused with opisthomere (o). The most prominent structure of the gonopods is the strongly developed interemediate lamella (l) connecting m and o. Mesally l with thickening (th), and completely covering m. Anteriorly, below tuberculated mesomeral lobe, m and l completely coalesced and continuing proximad as a unified structure. Opisthomere (o) fused with posterior part of l; mesally with one spine; distally with fimbriated velum (v) and small solenomere (s).

Paratype (females) 11.5–13.5 mm long, vertical diameter of the largest body ring 0.7–0.75 mm, body with 43 podous rings + 0 apodous rings + telson.

Variation. Paratype males 9–13 long, vertical diameter of the largest body ring 0.55–0.65 mm, body with 33–43 podous rings + 0–2 apodous rings + telson.

Distribution. This species is known only from two caves, in Croatia and Bosnia & Herzegovina (Fig. 19, open white circles).

Habitat. Kaverna 781 is a cavern in a tunnel which connects the Konavle Polje and the Adriatic Sea. The tunnel was constructed in 1958, in order to drain water from the Konavle Polje towards the sea. Kaverna 781 is mainly horizontal, with 142 m of explored passages (Ozimec et al. 2015b). Mean air temperature in the cavern is 13°C and relative humidity is 100%. The cavern is very interesting from the biospeleological point of view. In a recent investigation, Ozimec et al. (2015a) found more than 20 troglobiont and stygobiont taxa inhabit this relatively small cave. Kaverna 781 is locus typicus for the troglobiont coleopteran Graciliella kosovaci Njunjić, Perreau, Hendriks, Schilthuizen & Deharveng, 2016 . Of the diplopod fauna, two additional taxa were found, Brachydesmus stygivagus Verhoeff, 1899 and an undescribed species from the family Trichopolydesmidae .

Etymology. To denote the very small size of this species. Adjective.