The centipede genus Mecistocephalus Newport 1843 in the Indian Peninsula (Chilopoda Geophilomorpha Mecistocephalidae)

We performed a comprehensive revision of the species of the genus Mecistocephalus Newport 1843 in the Indian Peninsula (including the Western and Central Himalayas), based on the study of 111 specimens, on the critical evaluation of the literature data and on the examination of type material. Eight species were recognised and are here described and illustrated comparatively: M. punctifrons Newport 1843; M. pallidus (Silvestri 1919); M. superior (Silvestri 1919); M. nilgirinus Chamberlin 1920; M. aethelabis n. sp.; M. boriensis n. sp.; M. merkarensis n. sp.; M. silvestrii n. sp. Morphological characters traditionally used in Mecistocephalus taxonomy were tested for their intraspecific variation and for their value in species diagnosis. New useful diagnostic characters were found, such as the size of the antennal apical sensilla, the pattern of the cerrus and the number of teeth on the forcipular tarsungulum. Sexual dimorphism was found in body size and antenna elongation. Very peculiar features were found in the clypeus and forcipules of M. aethelabis. The geographical distribution of each species was analysed: four species are widespread over large areas, whereas the other four are limited to narrow ranges; most (possibly all) these species are exclusive to the Indian subcontinent. The following new synonymies are introduced: Lamnonyx insularis var. orientalis Silvestri 1919 = Mecistocephalus punctifrons Newport 1843; Mecistocephalus (Mecistocephalus) dekanius Verhoeff 1939 = Mecistocephalus punctifrons Newport 1843; Pauroptyx himalayanus Chamberlin 1920 = Mecistocephalus pallidus (Silvestri 1919); Mecistocephalus ethodon Chamberlin 1959 = Mecistocephalus superior (Silvestri 1919); Pauroptyx Chamberlin 1920 = Mecistocephalus Newport 1843. The following other taxonomic novelties are introduced: Mecistocephalus pallidus (Silvestri 1919) new status in Mecistocephalus (for Lamnonyx superior pallida); Mecistocephalus multispinatus (Silvestri 1919) new status (for Lamnonyx cephalotes var. multispinata); Tygarrup diversidens (Silvestri 1919) new combination (from Lamnonyx, ultimately in Mecistocephalus). Lectotypes are fixed for Lamnonyx insularis var. orientalis Silvestri 1919 and Mecistocephalus ethodon Chamberlin 1959.