Typhloiulus gracilis Antić, 2018

Antić, Dragan Ž., Dražina, Tvrtko, Rađa, Tonći, Lučić, Luka R. & Makarov, Slobodan E., 2018, Review of the genus Typhloiulus Latzel, 1884 in the Dinaric region, with a description of four new species and the first description of the male of Typhloiulus insularis Strasser, 1938 (Diplopoda: Julida: Julidae), Zootaxa 4455 (2), pp. 258-294 : 271-277

Typhloiulus gracilis Antić , new species

Figs 11 , 12 , 15B

Material examined: Type specimens. Holotype male, CROATIA, Island of Hvar , Pitve, Jama na Boroviku Pit (43.135617°N, 16.687400°E), 9 September 2013, T. Rađa leg. ( NHMSC) . Paratypes: 3 males (2 males—IZB, 1 male—NHMSC), 1 female ( NHMSC), 4 juveniles ( NHMSC), same data as for holotype.

Diagnosis. Typhloiulus gracilis is most similar to the members of the subgenus Inversotyphlus , viz. T. lobifer , T. gellianae , and herein described T. clavatus , and T. opisthonodus . 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 male sexual and habitus structures (see Discussion). The new species differs in the presence of very slender gonopods with a characteristic promere having a very slender apical half, curved mesad and slightly anteriad, with an almost lateral position in regard to mesomere. Typhloiulus gracilis also differs in the presence of a somewhat shorter and slightly curved downwards preanal process.

Description. Based on holotype (largest male) 47 mm long, vertical diameter of the largest body ring 2.6 mm, body with 57 podous rings + 0 apodous rings + telson. Colouration: ( Fig. 11A ). Depigmented, yellowish white. Head: ( Fig. 11B ). Labrum with three labral teeth, with 4 supralabral and 8+7 labral setae. Gnathochilarium with promentum in the form of an elongated kite; lamellae linguales with 4+4 setae in one row, stipites each with 3 setae. Antennae 3.55 mm long, their length 136% of vertical diameter of the largest body ring. Length of antennomeres I–VIII (in mm): 0.2 (I), 0.67 (II), 0.62 (III), 0.62 (IV), 0.69 (V), 0.52 (VI), 0.15 (VII), and 0.08 (VIII). Length/width ratio of antennomeres I–VII: 0.8 (I), 2.6 (II), 2.4 (III), 2.6 (IV), 2.4 (V), 1.8 (VI), and 0.75 (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. 11D ). The whole metazonal area with longitudinal striations. Midbody rings with ca. 20 short metazonal setae. Length of midbody setae ca. 10% of vertical diameter of rings. Telson: ( Fig. 11E ). Epiproct with elongated preanal process, slightly curved downwards and covered by long dorsal and lateral setae. Paraprocts rounded, with numerous long setae. Hypoproct lenticular, with 10 setae. Legs: First pair of legs modified, hook-shaped ( Fig. 12A ); coxa, postfemur, and tibiotarsus each with one seta, prefemur with four or five setae, femur each with two setae. Tibiotarsus with a small dorsal lobe (tarsal remnant) and tuberculate on the tip. Second pair of legs with poorly developed ventral pads on the tibia. Penis: ( Fig. 12C ). Bilobed. Lobes prominent, elongated. Ventral margin of body ring 7: ( Fig. 11C ). Well-developed, elongated, with rounded tip; almost right-angled to metazona. Gonopods: ( Figs 12B, D, E , 15B ). Very long and thin. Promere (p) and mesomere (m) shorter than opisthomere (o). Promere (p) longer than m; wide at the base; apical half very slender, curved mesad and slightly anteriad. Mesal lobe (ml) high and narrow, with three setae, one apical and two subapical. The telopodite (t) well-developed, tapering distad; apex almost at the same height as apex of ml. Mesomere (m) thin over all of its height, in the form of a rod, with antero-apical tuberculation and a small posterior node. Opisthomere (o) very slender, considerably longer than p and m. With poorly developed lamella (l) anteromesally; with one spine mesally; velum (v) unipartite, tapering anteriad, with fimbriated tip. Solenomere (s) narrow, distally with several short spines.

Paratype (female) 40 mm long, vertical diameter of the largest body ring 2.4 mm, body with 54 podous rings + 0 apodous rings + telson. Hypoproct with 10 setae.

Variation. The smallest paratype male 17.5 mm long, vertical diameter of the largest body ring 1.7 mm, body with 40 podous rings + 3 apodous rings + telson. Antennae 2.2 mm long in the smallest paratype male, their length 130% of vertical diameter of the largest body ring. Length of antennomeres I–VIII (in mm): 0.15 (I), 0.4 (II), 0.41 (III), 0.33 (IV), 0.43 (V), 0.33 (VI), 0.1 (VII), and 0.05 (VIII). Length/width ratio of antennomeres I–VII: 0.8 (I), 2.7 (II), 2.7 (III), 2 (IV), 2 (V), 1.7 (VI), and 0.8 (VII). Hypoproct with 1+1 long apical setae and 1+1 long, medial setae. The other two paratype males with 52 or 55 podous rings + 1 or 0 apodous rings + telson. Hypoproct with 8 setae.

Distribution: This species is known only from its type locality, Jama na Boroviku Pit on the Island of Hvar ( Fig. 20 , yellow circle).

Notes: Jama na Boroviku Pit is 30 m deep and is inhabited by other invertebrates, such as Spelaeobates (Pretneriella) pharensis langhofferi Müller, 1931 and Phaneropella (Phaneropella) lesinae ( Reitter, 1881) (both Coleoptera ); Chthonius sp., Microchthonius sp., and Neobisium sp. (all Pseudoscorpiones ); and Agardhiella sp. ( Stylommatophora ).

Etymology. To denote the slender, elongated gonopods. Adjective.

Figures

FIGURE 11. Typhloiulus gracilis sp. nov. A. Paratype juvenile (IZB), habitus, lateral view. B. Holotype male (NHMSC), anterior part of the body, lateral view. C. Paratype male (IZB), body rings 7 and 8, lateral view. D. Holotype male (NHMSC), midbody rings, lateral view. E. Paratype female (NHMSC), telson, lateral view. Arrow indicates ventral margin of body ring 7. Scale lines: 1 mm.

FIGURE 12. Typhloiulus gracilis sp. nov., paratype male (IZB). A. First pair of legs, anterior view. B. Promere, porsterior view. C. Penis, posterior view. D. Gonopods, mesal view. E. Gonopods, lateral view. Abbreviations: l: lamella; m: mesomere; o: opisthomere; p: promere; s: solenomere; t: telopodite; v: velum; ml: mesal lobe. Scale line: 0.3 mm.

FIGURE 15. Gonopods of representatives of the subgenus Inversotyphlus Strasser, 1962, mesal view. A. Typhloiulus clavatus sp. nov., holotype male (NHMSC). B. Typhloiulus gracilis sp. nov., paratype male (IZB). C. Typhloiulus opisthonodus sp. nov., holotype male (NHMSC). D. Typhloiulus lobifer Attems, 1951, male from Bitumen mine Minjera, island of Brač. E. Typhloiulus gellianae Makarov & Rađa, 2006, holotype male (ZDR). Scale lines: 0.1 mm.

FIGURE 20. Distribution of representatives of Inversotyphlus Strasser, 1962 and Typhloiulus edentulus Attems, 1951 (Attemsotyphlus Strasser, 1962).