Review of the Sunda weberi-group of Orthomorpha Bollman, 1893, with the description of two new species (Diplopoda, Polydesmida, Paradoxosomatidae)

Abstract

The weberi-group of Orthomorpha Bollman, only located in Sunda, comprises eight species Orthomorpha beroni n. sp., from Java, and O. melischl n. sp., from West Surnatra, are diagnosed, and O. weberi (Pocock, 1894) and O. conspicua (Pocock, 1894), both from Java, are redescribed. A key is provided to distinguish the eight species of the group. All of them, including both new forms, appear to be unusually uniform in gonopod structure. The rnain species-specific differences Iie in the position and outlines of the paraterga, the sculpture of the metaterga, arrangement of both pleurosternal keels and male tarsal brushes Hence the fact that O. beaumontli (Le Guillou, 1841), the type species of Orthomorpha, which is known only from a female holotype (supposedly from Borneo), does not preclude the taxon’s formal incorporation both into the weberi-group and into the key. Both new species differ from congeners and each other mainly in a peculiar combination of size, development of the paraterga, sculpture of the rnataterga and shape of the epiproct.