A REVIEW OF THE COMPLEX OF Trimeresurus hageni (LIDTH DE JEUDE, 1886) (SQUAMATA: VIPERIDAE) WITH DESCRIPTIONS OF THREE NEW INSULAR SPECIES FROM INDONESIA

Variations in morphological characters were investigated among 124 specimens covering the whole range of the large, Indo-Malayan pitviper complex of species currently known as Trimeresurus hageni (Lidth de Jeude, 1886). Herein, we redefine T. hageni and discuss and confirm the validities of its description and name-bearing type; the lectotype is redescribed. Morphological analyses show that at least four taxa, distinct at species level, are currently confused under the combination T. hageni. As a consequence, three new insular species are described, from Nias Island, Siberut Island, and Simeulue Island. All these three new species differ from T. hageni sensu stricto by a combination of differences in scalation and pattern. T. hageni sensu stricto inhabits Sumatra and Bangka Island, as well as West Malaysia, Singapore and southern Thailand. The new species are compared with T. sumatranus and T. gunaleni, also present on Sumatra