The millipede tribe Brachyiulini in the Caucasus (Diplopoda, Julida, Julidae) Author Vagalinski, Boyan Institute of Biodiversity and Ecosystem Research at the Bulgarian Academy of Sciences, 2 Yurii Gagarin Street, 1113, Sofia, Bulgaria boyan_vagalinski@excite.com Author Golovatch, Sergei I. Institute for Problems of Ecology and Evolution, Russian Academy of Sciences, Leninsky pr. 33, Moscow 119071, Russia text ZooKeys 2021 2021-08-30 1058 1 127 http://dx.doi.org/10.3897/zookeys.1058.68628 journal article http://dx.doi.org/10.3897/zookeys.1058.68628 1313-2970-1058-1 654932353DDB4E1B8848EAB69F2C20FD 61FB9E86BEE45968AAC868B21AF7ED86 Genus Omobrachyiulus Lohmander, 1936 Updated diagnosis. A genus of Brachyiulini differing from other contribal genera by the following combination of characters: promeres positioned completely anteriorly in relation to opisthomeres; opisthomere with a mesomeroidal lobe on anterior surface, and with a basoposterior process either completely absent (rarely) or present as a vertical lobe or ridge, with only apical part freely protruding; sometimes with a faint lateral lobe, but never with a well-developed lateral process; solenomere well differentiated, mostly slender. Updated general description. Small to medium-sized Brachyiulini (L (males) = 10-33 mm). Ommatidia present. Ozopores set tightly behind pro-metazonal suture at least on more anterior body rings. Epiproct present, varying in length. Male hypoproct either broad, dentate at margin and trapezoidal or semi-circular/semi-elliptic. Male mandibular stipites moderately to considerably expanded, forming a distinct anterior/anteroventral corner. Male pleurotergum 7 significantly bulging only in some species. Male walking legs ventrally with two well-developed adhesive pads, one each on postfemur and tibia, postfemoral pads rarely lacking in leg pair 2. Penis short and stout, usually considerably compressed anterocaudally, with short or indistinct apical lobes. Gonopods: In situ: promeres slightly to considerably protruding outside gonopodal sinus, directed completely ventrad. Promere subequal to or higher than opisthomere, mostly roughly leaf-shaped, caudal side sometimes forming small lobes, but bearing no distinct processes; flagellum usually much longer than height of promere. Opisthomere from stout to relatively slender; basoposterior process usually represented by a differently pronounced vertical lobe, apically forming a variously shaped and freely protruding outgrowth; an anterior process usually present, varying in shape and size; a mesomeroidal lobe always present, mostly rounded, varying in size and prominence; solenomere always conspicuously protruding from CBO, usually slender and tubular. Vulva: Subcylindrical. Bursa usually with a distinct, more or less obtuse, postero-apical margin. Opening narrow oval or cleft-like, positioned apically. Operculum usually somewhat longer than or subequal to, rarely shorter than, bursa. Receptaculum seminis: central tube narrow, mostly straight, forming no distinct central ampulla; posterior tube narrow, usually more or less twisted, ending in an ovoid or spherical posterior ampulla. Species groups Seven species groups can be recognised within the circum-east Mediterranean genus Omobrachyiulus : The Omobrachyiulus caucasicus group is the most diverse one and includes both Caucasian and Balkan-south Carpathian species; the Omobrachyiulus hortensis , Omobrachyiulus implicitus , Omobrachyiulus roseni , and Omobrachyiulus sevangensis groups each comprises three or four Caucasian endemics; O. mesorientalis Vagalinski & Golovatch, 2019 from Israel and Lebanon, as well as O. beroni (Strasser, 1973) from southern Bulgaria are morphologically the most isolated/disjunct congeners, each representing a group of its own ( Vagalinski and Golovatch 2019 ; Vagalinski et al. in prep., respectively). The former five groups are here characterised by gonopodal and vulval structures which show no clear-cut differences, but rather gradual transitions between the groups. Clear-cut diagnoses of the species groups can therefore not be made. Nevertheless, the recognition of these species assemblages is useful for it allows for certain patterns in the distribution of the Caucasian Omobrachyiulus to be drawn (see Maps 2 , 3 ). The Opisthomere caucasicus group Characterisation. Both gonopod pairs subequal in height. Promere with a well-developed distal groove. Opisthomere rather slender, with a well-pronounced mesomeroidal lobe, a basoposterior process with a moderately to strongly pronounced proximal part, ending with a variously shaped apical outgrowth, an anterior process in the shape of a small spine or rod of various length, a deep anteromesal sinus, a flagellum channel overgrown with short to moderately long spiniform filaments, and a more or less slender, apically often bipartite solenomere. Vulva with operculum subequal (from slightly lower to slightly higher) to bursa. Included species. O. adsharicus (Lohmander, 1936) O. caucasicus (Karsch, 1881), comb. nov. (= Brachyiulus brachyurus Attems, 1899, the type species of the genus) O. curvocaudatus (Lignau, 1903) O. divaricatus (Lohmander, 1936) O. geniculatus (Lohmander, 1928) O. macrourus (Lohmander, 1928) O. platyurus (Latzel, 1884) (South Carpathians, Romania; Banat, Romania/Serbia) O. strasseri Vagalinski & Lazanyi , 2018 (Andros, Greece) O. unugulis Vagalinski, sp. nov.