Svaniulus Vagalinski, 2021

Vagalinski, Boyan & Golovatch, Sergei I., 2021, The millipede tribe Brachyiulini in the Caucasus (Diplopoda, Julida, Julidae), ZooKeys 1058, pp. 1-127 : 1

Genus Svaniulus Vagalinski gen. nov.

Type species.

Svaniulus ryvkini sp. nov., by present designation.

Included species.

Svaniulus ryvkini sp. nov.

Svaniulus waltheri sp. nov.

Diagnosis.

A genus of Brachyiulini differing from contribal genera by the following combination of characters: promeres positioned anteriorly and only slightly laterally in relation to opisthomeres; caudal surface of promere bearing a strongly developed mesal process; opisthomere possessing a broad and flattened basoposterior process and a faint mesomeroidal lobe, and lacking lateral and anterior processes; solenomere simple, more or less slender, ending with a sharply pointed tip; vulva subconical, bursa with completely fused valves (forming neither an opening nor a cleft), a supposed autapomorphy.

Name.

Honours the Svan people, the indigenous inhabitants of Svanetia, northwestern Georgia, whence the type species of the new genus originates. Gender: masculine.

General description.

Medium-sized (L (males) = 23-28 mm) Brachyiulini.

Ommatidia present.

Ozopores set tightly behind pro-metazonal suture at least on more anterior body rings.

Epiproct well-developed, relatively (not conspicuously) long.

Hypoproct rounded trapezoidal to semi-circular, ventrally with two distal paramedian setae.

Male mandibular stipites considerably expanded, forming a distinct ventro-anterior corner.

Male pleurotergum 7 significantly bulging.

Male walking legs ventrally with two well-developed adhesive pads, one each on postfemur and tibia.

Penis short and stout, with very short apical lobes and small terminal lamellae.

Gonopods:

In situ: promeres considerably protruding outside gonopodal sinus, directed partly caudad, opisthomeres visible only with their apical parts.

Promere slightly higher than opisthomere, elongate, bearing a long, stout, mesal process on caudal side; flagellum slightly shorter than height of promere.

Opisthomere slender; basoposterior process well-developed, broad, flattened frontocaudally; anterior and apicoposterior processes absent; mesomeroidal lobe shaped as a weakly pronounced ridge; solenomere long and slender, distally bipartite, the frontal part ending in a fine, sharply pointed tip.

Vulva:

Subconical.

Bursa without distinct postero-apical margin.

Opening or median cleft absent - the two valves completely fused to one another.

Operculum subequal in height to bursa.

Receptaculum seminis: central tube short and narrow, ending in a distinct central ampulla; posterior tube long and narrow, ending in a subspherical posterior ampulla.

Remarks.

The new genus resembles Omobrachyiulus in the opisthomere having a mesomeroidal lobe (although weakly pronounced), a character not seen in other members of Brachyiulini . On the other hand, the long and freely protruding solenomere and the micro-papillary branches (albeit very small) apically on the opisthomeral basoposterior process suggest proximity to Colchiobrachyiulus , while the mesal process caudally on the promere might be homologous to the similarly positioned structure characteristic of the subgenus Colchiobrachyiulus Rhamphidoiulus Attems, 1905 of the genus Cyphobrachyiulus Verhoeff, 1900. Anyhow, this unique combination of gonopodal characters, coupled with the supposedly autapomorphic condition of the vulva make the establishment of the new genus warranted.