Revision of the Southeast Asian millipede genus Orthomorpha Bollman, 1893, with the proposal of a new genus (Diplopoda, Polydesmida, Paradoxosomatidae)

Abstract

The large genus Orthomorpha is rediagnosed and is shown to currently comprise 51 identifiable species ranging from northern Myanmar and Thailand in the Northwest to Lombok Island, Indonesia in the Southeast. Of them, 20 species have been revised and/or abundantly illustrated, based on a restudy of mostly type material; further 12 species are described as new: Orthomorpha atypica sp. n., Orthomorpha communis sp. n., Orthomorpha isarankurai sp. n., Orthomorpha picturata sp. n., Orthomorpha similanensis sp. n., Orthomorpha suberecta sp. n., Orthomorpha tuberculifera sp. n.,Orthomorpha subtuberculifera sp. n. and Orthomorpha latiterga sp. n., all from Thailand, as well as Orthomorpha elevata sp. n.,Orthomorpha spiniformis sp. n. and Orthomorpha subelevata sp. n., from northern Malaysia. The type-species Orthomorpha beaumontii (Le Guillou, 1841) is redescribed in due detail from male material as well, actually being a senior subjective synonym of Orthomorpha spinala (Attems, 1932), syn. n. Two additional new synonymies are proposed: Orthomorpha rotundicollis (Attems, 1937) = Orthomorpha tuberculata (Attems, 1937), syn. n., and Orthomorpha butteli Carl, 1922 = Orthomorpha consocius Chamberlin, 1945, syn. n., the valid names to the left. All species have been keyed and all new and some especially widespread species have been mapped. Further six species, including two revised from type material, are still to be considered dubious, mostly because their paraterga appear to be too narrow to represent Orthomorpha species. A new genus, Orthomorphoides gen. n., diagnosed versus Orthomorpha through only moderately well developed paraterga, coupled with a poorly bi- or trifid gonopod tip, with at least some of its apical prongs being short spines, is erected for two species: Orthomorpha setosus (Attems, 1937), the type-species, which is also revised from type material, and Orthomorpha exaratus (Attems, 1953), both comb. n. ex Orthomorpha.

Review of the Southeast Asian millipede genus Antheromorpha Jeekel, 1968 (Diplopoda, Polydesmida, Paradoxosomatidae)

“…21). This gap strongly reminds of that observed between Orthomorpha lauta Golovatch, 1998 and Orthomorpha insularis Pocock, 1895 (Likhitrakarn et al 2011). …”

“…Orthomorpha paviei – Jeekel 1963: 265 (M); 1964: 359 (M); 1968: 56 (M); Golovatch 1998: 42 (D); Enghoff et al 2004: 34 (M); Enghoff 2005: 97 (M); Likhitrakarn et al 2011: 52 (D); 2014: 2 (D, R).…”

“…The main difference between these two genera lies in Orthomorpha spp. showing only a poorly differentiated gonopod tip, usually feebly bi- or trifid (Likhitrakarn et al 2011). Antheromorpha species have hitherto been recorded in Myanmar (9), Thailand (2), China (1) and Vietnam (1).…”

The millipede genus Orthomorpha Bollman, 1893 in Laos (Diplopoda, Polydesmida, Paradoxosomatidae), with descriptions of new species

“…The above fresh samples show only slight variations, mainly a darker coloration, as opposed to the types which have recently been redescribed in due detail (Likhitrakarn et al 2011). This species is thus new to the fauna of Laos, suggesting a far wider distribution in Indochina.…”

“…Among them, only three have hitherto been recorded in Laos: the pantropical anthropochore Orthomorpha coarctata (De Saussure, 1860), as well as Orthomorpha rotundicollis (Attems, 1937) and Orthomorpha scabra Jeekel, 1964, both latter species also shared with Vietnam (Likhitrakarn et al 2011, 2014). …”