Hylopachyiulus ocellatus Antić and Akkari, 2018

Antić, Dragan Ž., Rađa, Tonći & Akkari, Nesrine, 2018, Revision of the genus Hylopachyiulus Attems, 1904, with a description of a new species from Croatia (Diplopoda, Julida, Julidae), Zootaxa 4531 (2), pp. 225-241 : 231-234

Hylopachyiulus ocellatus Antić and Akkari , sp. nov.

Figs 4 , 5 , 8C, D

Material examined: Type specimens. Holotype male, Croatia, Dalmatia, Dicmo, meadow (43.635948°N, 16.593139°E), 0 5 May 2006, leg. T. Rađa ( NHMSC).

Paratypes: 1 male ( IZB), same data as for holotype ; 1 male ( NHMW9433 ), same data as for holotype .

Diagnosis. The new species clearly differs from its congeners in the presence of ommatidia (vs. absence in H. corylorum and H. pygmaeus ), the presence of a short and blunt preanal process (vs. long and sharp in H. corylorum and H. pygmaeus ) and the presence of a very short and subtriangular mesomeral process (vs. short and hookshaped in H. corylorum or elongated and slender in H. pygmaeus ).

Description. Holotype (male) 9.5 mm long, vertical diameter of the largest body ring 0.55 mm, body with 43 podous rings + 2 apodous rings + telson. Paratype males 8 and 10 mm long, vertical diameter of the largest body rings 0.5 and 0.55 mm, body with 35 and 45 podous rings + 2 and 3 apodous rings + telson, respectively.

Colouration: ( Fig. 4 ). Depigmented. Yellowish-white.

Head: ( Fig. 4 B–D). With 2–4 ommatidia. Number differs within the same specimen. If two or three ommatidia then arranged in one line, if four then in triangle. Labrum with three labral teeth, with 4 (2+2) supralabral and 14 (7+7) labral setae. Gnathochilarium with kite-shaped promentum; lamellae linguales with 3+3 setae in one row, stipites each with 4 setae (one short medial and three long apical). Antennae 0.7 mm long (paratype male), length 140% of vertical diameter of the largest body ring. Length of antennomeres I–VIII (in mm): 0.08 (I), 0.16 (II), 0.1 (III), 0.1 (IV), 0.15 (V), 0.07 (VI), 0.02 (VII), and 0.02 (VIII). Length/width ratio of antennomeres I–VII: 1.3 (I), 2 (II), 1.3 (III), 1.1 (IV), 1.3 (V), 0.8 (VI), and 0.3 (VII). Antennomeres V and VI each with a few large bacilliform sensillae presenting only dorsally (exteriorly); smaller on antennomere VI.

Body rings: ( Fig. 4E ). Metazonal striations barely visible. Midbody rings with ca. 12 short metazonal setae. Length of midbody setae ca. 15% of vertical diameter of rings.

Telson: ( Fig. 4G ). Epiproct with a short and blunt preanal process covered by long dorsal and lateral setae. Paraprocts rounded, with ca. 10–12 long setae each. Hypoproct lenticular, with two long setae.

Ventral margin of body ring 7: ( Fig. 4F ). Poorly developed, subquadrangular.

Legs: First pair of legs modified, hook-shaped ( Fig. 5A ). With three podomeres. Femur, postfemur and tibiotarsus fused, only a small remnant of division of femur is noticeable. Coxa and tibiotarsus each with one seta, prefemur and femoral remnants with two setae each. Tibiotarsus with a small tarsal remnant in the form of a small tubercule. The tip of the first pair of legs somewhat acuminate. Second pair of legs somewhat enlarged in comparison with the rest of walking legs. Legs without ventral pads.

Gonopods: ( Figs 5 B–F, 8C, D). Promere (p) slightly higher than posterior gonopods; slender in all views, but somewhat wider at the base; with almost parallel sides; somewhat curved posteromesad. Basal half caudally with two lobes: mesal (ml) and lateral (ll), both almost the same height; ml distally countinues as thin lamella parallel to the mesal margin of p; distal part of ll rounded. Distal third caudally with thin, lamellar and denticulated ridge (dr). Posterior gonopods with strongly chitinized anterior part with short, subtriangular mesomeral process (m) and thin solenomere (s) as the highest part of the posterior gonopods. Solenomere apically with two short, opposite oriented, processes. The rest of the posterior gonopods is represented by a well-developed, hyaline and spoon-shaped, distally serrated opisthomeral lamella (l). The lamella is open on the mesal side, and in its interior there are two oppositely oriented rows of short dense setae.

Distribution. This species is known only from its type locality, near Dicmo in Dalmatia, Croatia ( Fig. 9 , red circle).

Notes. Three males of this species were found under a large, deeply embedded stone in the meadow.

Etymology. The specific name refers to the presence of ommatidia in the new species, contrary to its congeners. Adjective.

Figures

FIGURE 4. Hylopachyiulus ocellatus sp. nov. A. Holotype male (NHMSC), habitus, lateral view. B. Holotype male (NHMSC), head, lateral view. C. Paratype male (IZB), head, lateral view. D. Paratype male (NHMW9433), head, lateral view. E. Holotype male (NHMSC), midbody rings, lateral view. F. Paratype male (IZB), half of the body ring 7, lateral view. G. Holotype male (NHMSC), telson, lateral view. Scale lines: 1 mm (A), 0.5 mm (B–G).

FIGURE 5. Hylopachyiulus ocellatus sp. nov., paratype male (IZB). A. First pair of legs, anterior view. B. Left promere, posterior view. C. Right gonopods, lateral view. D. Right gonopods, mesal view. E. Left posterior gonopods, anterior view. F. Left posterior gonopods, antero-mesal view. Abbreviations: l: opisthomeral lamella; m: mesomeral process; p: promere; s: solenomere; dr: promeral denticulated ridge; ll: lateral promeral lobe; ml: mesal promeral lobe. Scale line: 0.1 mm.

FIGURE 8. Hylopachyiulus spp., gonopods. A–B. Hylopachyiulus corylorum (Verhoeff, 1907) male (NHMW9434). A. Right promere (flipped horizontally), posterior view. B. Right posterior gonopods (flipped horizontally), lateral view. C–D. Hylopachyiulus ocellatus sp. nov., paratype male (IZB). C. Left promere, posterior view. D. Left posterior gonopods, mesal view. E–F. Hylopachyiulus pygmaeus (Attems, 1904), paralectotype male (NHMW9438). E. Right promere (flipped horizontally), posterior view. F. Right gonopods (flipped horizontally), mesal view. Abbreviations: l: opisthomeral lamella; m: mesomeral process; p: promere; r: rod-like process; s: solenomere; dr: promeral denticulated ridge; ll: lateral promeral lobe; ml: mesal promeral lobe. White arrows indicate the height of the lateral and mesal lobes (A, C, E) or the mesomeral processes (B, D, F). Black arrow indicates a rod-like process. Scale line: 0.1 mm.

FIGURE 9. Distribution of the species of Hylopachyiulus Attems, 1904.