Pacifiosoma shabalini, Mikhaljova, 2021

Mikhaljova, Elena V., 2021, The millipede family Diplomaragnidae Attems, 1907 in the Asian part of Russia with the descriptions of two new genera and seven new species (Diplopoda, Chordeumatida), Zootaxa 5060 (1), pp. 1-44 : 30-32

Pacifiosoma shabalini sp. nov.

Figs 49–55

Material examined. Holotype: male ( FSCB), Russia: Primorsky krai, Dalnerechensky District, environs of Martynova Polyana village , 9–12.VII.2009, leg. S.A. Shabalin. Paratype: 1 female ( FSCB), same locality as in holotype, 9–12.VII.2009, leg. S.A. Shabalin.

Diagnosis. Differs from congeners mainly by the shape of a gonopod posteror angiocoxal process with a widely rounded apex and a subapical rounded outgrowth covered with broad papillae, as well as in the shape of the colpocoxite, coupled with an absence of an anterior angiocoxal processes.

The species seems to be particularly similar to Pacifiosoma asperum but differs in a large, widely rounded apex of the posteror angiocoxal process (vs smaller not widely rounded in P. asperum ), an absence of the long basal margin of the lateral colpocoxite blade twisted to the posterior surface of the colpocoxite (vs a long basal margin in P. asperum : see Mikhaljova 2016: Fig. 3 , bm) and in the shape of the colpocoxite.

Description. Male. Length about 11 mm, width about 0.9 mm with paraterga. Coloration in alcohol light brown. Legs marbled brownish, darker distad. Antennae brown. Eye patches black, with 23–25 ocelli in the center. Body with 32 rings. Collum semicircular. Both collum and ring 2 narrower than head with genae. Ring 2 somewhat wider than collum. Paraterga beginning on ring 2(3), well developed on rings 5–26, reduced on rings 27–28, onward missing. Metazonital macrochaetae in a transverse row on somites 30–31, like an extended triangle on preceding somites. Anterolateral macrochaetae shortest, faintly clavate. Caudolateral macrochaetae longest. Medial and caudolateral macrochaetae pointed, but not very sharply so. Axial suture poorly developed.

Legs long and slender. Leg pairs 1 and 2 typically reduced in size, with usual tarsal brushes. Other pregonopodal legs somewhat enlarged. Claw of the leg pairs 1–2 at base with a long setoid outgrowth ventrally and two small additional claws dorsally. Leg pairs 3–7 with a group of funnel–shaped tarsal papillae apically near claw; size of papillar tarsal field gradually increasing toward gonopods. Claw of leg pairs 3–7 at base with a long setoid outgrowth ventrally but without additional claws dorsally. Postgonopodal legs (including leg pairs 10 and 11) without tarsal papillae. Claw of legs 10 and 11 at base with a long setoid outgrowth ventrally and two small additional claws dorsally. Claw of midbody legs at base with two small additional claws dorsally and a long setoid outgrowth ventrally. Claw of hindmost legs at base with a long setoid outgrowth ventrally only.

Legs 10 and 11 with coxal glands. Coxa 10 with a caudoventral, small conical setose process ( Fig. 55 ). Trochanter 10 with a tiny ventrocaudal outgrowth setose apically. Trochanter 11 with a caudoventral setose fingershaped process rounded apically ( Fig. 54 ).

Gonopods as in figs 49–52.Anterior gonopod telopodites flagelliform, their distal parts positioned inside narrow sheath groove with elevated edges. Apices of the anterior gonopods telopodites (at, Fig. 52 ) ribbon-shaped, covered with tiny longitudinal grooves. Posterior gonopod colpocoxites fused basally, their distal parts curved caudally, apices hook-shaped curved posterad. Each colpocoxite entire. Colpocoxite sheath groove without evident processes. Posterior gonopod angiocoxites with moderately developed elongated subglobules (sg, Fig. 49 ) in posterior view, depressed centrally in anterior view. Posterior angiocoxal process (pp, Fig. 49 ) large, with large widely rounded apex covered with broad papillae and subapical rounded outgrowth covered with simple papillae. Anterior angiocoxal process absent. Posterior gonopod telopodite 2-segmented, setose; distal segment large, basal segment with a thin stem.

Female. Length about 13 mm, width with paraterga 0.8–0.9 mm. Body with 32 rings. Numerous macrochaetae broken off. Eye patch each composed of at least 27 ocelli. Other nonsexual characters as in male. Vulvae small, near ovoid ( Fig. 53 ). Valves with long setae in distal parts. Operculum short without setae.

Etymology. The species is named in honor of the collector S.A. Shabalin, Russian entomologist. A noun in genitive.

Figures

FIGURES 49–55. Pacifiosoma shabalini sp. nov., male holotype, female paratype. 49, gonopods, caudal view; 50, distal part of gonopods, caudal view; 51, gonopods, front view; 52, central part of gonopods; 53, vulva, ventral view; 54, coxae and trochanters 11, caudal view; 55, coxae and trochanters 10, front view; pp, posterior angicoxal process; sg, subglobule of posterior angiocoxite; cl, colpocoxites; at, anterior gonopod telopodite. Scales: 20 μm (Figs 50, 52–55), 100 μm (Figs 49, 51).

FIGURES 3–7. Diplomaragna budilovi sp. nov., male holotype. 3, 7, gonopods, caudal view; 4, posterior angiocoxal processes and colpocoxites, caudal view; 5, gonopods, front view; 6, basal part of gonopods, caudal view; c, horn; pp, posterior angicoxal process; ap, anterior angiocoxal process; cx, coxosternum; at, anterior gonopod telopodite. Scales: 20 μm (Fig. 6), 100 μm (Figs 3–5), 0.5 mm (Fig. 7).