Hylopachyiulus pygmaeus ( Attems, 1904 )

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 : 234

Hylopachyiulus pygmaeus ( Attems, 1904)

Figs 6–8E, F

Pachyiulus (Hylopachyiulus) pygmaeus Attems, 1904: 183 (first description)

Micropachyiulus pygmaens (sic!)—Verhoeff 1908: 460 (new combination)

Micropachyiulus (Micropachyiulus) pygmaeus —Verhoeff 1908: 461

Hylopachyiulus pygmaeus —Attems (1926: 257, 258) (new combination)

Hylopachyiulus corylorum —Strasser (1966: 44) (synonymization)

Hylopachyiulus likanus— Strasser (1966: 44) (synonymization)

Material examined: Lectotype (herein designated): 1 male ( NHMW9439 ) Banja Luka, Bosnia & Herzegovina, leg. Attems ( Fig. 6 ).

Paralectotypes: 1 male dissected ( NHMW9438 ) ( Fig. 8E, F ) , 4 females, 1 broken specimen, 1 micropreparation ( NHMW3182 ), Banja Luka, Bosnia and Herzegovina, leg. Attems.

Diagnosis. H. pygmaeus clearly differs from both congeners by a slender and straight preanal process with a thin distal half (vs. robust and curved ventrad in H. corylorum or short and blunt in H. ocellatus sp. nov.), robust mesal lobe of promere which is significantly higher than lateral lobe (vs. both lobes are of the same height in H. corylorum and H. ocellatus sp. nov.) or very slender and elongated mesomeral process which is half the length of the posterior gonopods (vs. short and hook-shaped or short and subtriangular in H. corylorum and H. ocellatus sp. nov., respectively). In addition, H. pygmaeus differs from H. ocellatus sp. nov. in absence of ommatidia (vs. presence in H. ocellatus sp. nov.).

Descriptive notes. Small blind species. Males 7.4–7.8 mm long, vertical diameter of largest body ring ca. 0.4 mm, body with 36–38 podous rings + 2 apodous rings + telson. Females 8–10.5 mm long, vertical diameter of largest body rings 0.5–0.6 mm, body with 38–46 podous rings + 1–3 apodous rings + telson.

Colouration: ( Figs 6A , 7A ). All specimens pale yellowish.

Head: ( Figs 6B , 7B ). With two frontal setae, ommatidia absent in all specimens. Antennae 0.6 mm long (paralectotype male), length 150% of vertical diameter of the largest body ring. Length of antennomeres I–VIII (in mm): 0.06 (I), 0.1 (II), 0.11 (III), 0.09 (IV), 0.14 (V), 0.06 (VI), 0.02 (VII), and 0.02 (VIII).

Body rings: ( Figs 6 , 7 ) With short metazonal setae. Length of midbody setae ca. 15% of vertical diameter of rings.

Telson: ( Figs 6C , 7C ). Epiproct with a protruding, slender and sharp, almost straight preanal process covered by long dorsal and lateral setae.

Legs: First pair of legs modified, hook-shaped. Legs without ventral pads.

Gonopods: ( Fig. 8E, F ). Promere (p) higher than the posterior gonopods, with a broad base and parallel margins. Basal half posteriorly equipped with a robust, somewhat twisted mesal lobe (ml) protruding much higher than the lateral one (ll). Posterior gonopod with a slender mesomeral process (m), half the length of the posterior gonopods, distally acuminate and curved anteriad. Opisthomeral lamella (l) spoon-shaped, hyaline, presenting strong serrations on the margin and short dense setae on its mesal surface. Solenomere (s) short and thin, protruding from the margin of the lamella.

Distribution. The species is known only from its type locality in Banja Luka, Bosnia and Herzegovina ( Attems 1904) ( Fig. 9 , blue circle).

Notes. Attems (1904) stated that species was found in scrubland in a hilly area.

Type locality. Banja Luka, Bosnia and Herzegovina.

Figures

FIGURE 6. Hylopachyiulus pygmaeus (Attems, 1904), lectotype male (NHMW9439). A. Habitus, lateral view. B. Head with anterior rings, lateral view. C. Posterior rings with telson, lateral view. Scale lines: 1 mm (A), 0.5 mm (B, C).

FIGURE 7. Hylopachyiulus pygmaeus (Attems, 1904), paralectotype female (NHMW3182). A. Habitus, lateral view. B. Head with anterior rings, lateral view. C. Posterior rings with telson, lateral view. Scale lines: 1 mm (A), 0.5 mm (B, C).

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.