A redescription and a synonym in the South Asian millipede genus Xenobolus Carl, 1919 (Spirobolida, Pachybolidae) Author Sankaran, Pradeep M. Author Sebastian, Pothalil A. text Zootaxa 2020 2020-05-22 4780 1 165 179 journal article 21913 10.11646/zootaxa.4780.1.8 b31f6b64-6284-47c8-a2ff-f2d027785f92 1175-5326 3839653 11054D3F-A1A3-4B78-9F9A-248AAE77F6D7 Genus Xenobolus Carl, 1919 Diaphoropus Silvestri, 1897 ( type species Iulus (recte: Julus ) carnifex Fabricius, 1775 , by original designation). Preoccupied name. Xenobolus Carl, 1919 ( type species Iulus (recte: Julus ) carnifex Fabricius, 1775 , by original designation). Erythroprosopon Verhoeff, 1936 ( type species Erythroprosopon phoenix Verhoeff, 1936 , by monotypy). Synonymised by Hoffman (1962) . Diagnosis. Medium-sized, colourful pachybolid ( Fig. 1A, B ): male and female nearly equal in length and thickness. Mature individuals with 50 body rings. No apodous rings in front of telson ( Fig. 2C, E ). Scobinae absent. Tarsal pads on male legs lacking. Body ring 6 in males greatly enlarged ventrally, protecting the gonopod pouch ( Fig. 2A ). Anterior gonopods massive ( Fig. 5A, B ), not completely retractable into pouch; sternite with a median process ( Figs 5A , 6A ); coxite anteriorly with a slender mesal process ( Figs 5A, B , 6A, B ); telopodite anteriorly with a narrow mesal process ( Figs 5A, B , 6A, B ). Posterior gonopods with a narrow sternite ( Fig. 6E ); coxite unmodified; telopodite consisting of two branches, both bent mesad ( Figs 5C, D , 6D, E ), main branch with an apical fringe directed towards mesal branch ( Fig. 6 D–F), mesal branch anteriorly with lateral processes ( Fig. 6 D–F). Neither membranous folds nor a connection between mesal and main branches ( Fig. 6D ). Relationship. Carl (1919) treated Xenobolus as a member of Trigoniulidae Attems, 1909 and related it with Trigoniulus Pocock, 1894 . Verhoeff (1936) included Xenobolus in Spiromimidae Brölemann, 1913 . Hoffman (1962) , who rejected both of these views, proposed its inclusion in the Pachybolidae and suggested informally a close relationship with Stenobolus Carl, 1918 and Mystalides Attems, 1910 (now a synonym of Aphistogoniulus Silvestri, 1897 ). A recent phylogenetic treatment based on morphological characters alone suggested a relationship of Xenobolus with the Malagasy genus Spiromimus de Saussure & Zehntner, 1901 (Wesener & Enghoff 2009). Even though Xenobolus was found to be sister to Spiromimus , these authors hesitated to accept its inclusion in Spiromiminae Brölemann, 1913 and argued that both these genera were close. Subfamily inclusion. Currently Xenobolus is not assigned to any of the four subfamilies of Pachybolidae viz. , Centrobolinae Hoffman, 1980 , Pachybolinae , Spiromiminae and Trigoniulinae Attems, 1909 ( Wesener et al. 2008 ). Irrespective of its weak relationship with Spiromimus , Wesener and Enghoff (2009) excluded it from Spiromiminae . Species included. Only Xenobolus carnifex ( Fabricius, 1775 )