Metonomastus radjai, Antic, Dragan, Vagalinski, Boyan, Stoev, Pavel & Golovatch, Sergei, 2018

Antic, Dragan, Vagalinski, Boyan, Stoev, Pavel & Golovatch, Sergei, 2018, Two new species of the millipede genus Metonomastus Attems, 1937 from the Balkan Peninsula (Diplopoda, Polydesmida, Paradoxosomatidae), ZooKeys 786, pp. 43-57 : 43

Metonomastus radjai sp. n. Figs 5, 6, 7, 8, 9

Material examined.

Holotype male (NHMSC), Croatia, Dalmatia, island of Mljet, Blato, near Kozarica, under stones, 23.XII.2015, T. Rađa leg.

Paratypes.

1 male (NHMSC), 2 males (IZB), 4 females (NHMSC), 7 females (IZB), 4 juveniles (IZB), same data as holotype.

Etymology.

The new species is named after the collector, Tonći Rađa, a renowned Croatian biospeleologist who discovered numerous new or interesting arthropods. Noun in genitive case.

Diagnosis.

The new species belongs to the Metonomastus group of species with two postfemoral branches, but clearly differs from all of these by the presence of a well-developed, broad, lamellar solenophore (= tibiotarsus) directed strongly mesad, and proximally curved ventrad. The solenomere is without additional processes and is also directed strongly mesad.

Description.

Length 3.7-3.9 mm (males), 4.3-5 mm (females). Width of midbody rings 0.30-0.33 and 0.37-0.4 mm (males), 0.42-0.44 and 0.47-0.5 mm (females) on pro- and metazonae, respectively. Holotype male 3.7 mm long, 0.3 and 0.37 mm wide on midbody pro- and metazonae, respectively.

All other characters as in M. petrovi sp. n., except as follows.

Microreticulated texure more obvious (Figs 6A, 8A, B). Width of head 0.42-0.44 mm (males), 0.5-0.55 mm (females). Antennomere length 2 = 3 = 6> 4 = 5> 7> 1 (Figure 6E). Postcollum metaterga each with a barely visible, mid-dorsal, transverse sulcus (Figure 8A, B). Pleurosternal carinae present on rings 2-4 in the form of small denticles, more strongly developed on 2nd ring (Figure 6A, C). Legs about 1.5 times as long as midbody height in both sexes. In males, pregonopodal legs each with a distinct dorsobasal hump on prefemur; leg-pairs 5-7 each with a ventrobasal femoral adenostyle (Figure 7B, C).

Gonopods (Figs 8E-G, 9): Coxite (cx) massive, slightly elongated, laterally with three setae, one being particularly long. Prefemorite (pf) subquadrate in ventral and dorsal views, somewhat narrower in lateral and mesal views, about as long as acropodite, densely setose ventromesally. Acropodite represented by two processes: solenomere (sl) and solenophore (sph). Both solenomere and solenophore simple and directed mesad. Solenomere ventral in position, slender, acuminate, distally terminating in two small teeth. Solenophore strongly developed, dorsal in position, wide, lamellar, proximally curved ventrad. Seminal groove running through dorsomesal side of prefemorite, then shifting laterodistally through solenomere.

Remarks.

This species was found under stones next to a dry stone wall close to the seashore.