ANNOUNCEMENTS
Biogeography is the study of species distribution patterns across space and time. One of its approaches, historical biogeography, evaluates the role of three main evolutionary processes- vicariance, dispersal and extinction- in the current distribution of biota. A large proportion of research in this field is conducted on the Gondwanan vicariance hypothesis, which has been invoked to explain the biogeography of the Southern Hemisphere. Due to its position in Gondwana and subsequent drift, Peninsular India plays a crucial role in evaluating the biogeography of the Asian region. In this study, we assessed the origin and role of biogeographic processes on the distribution of an ancient order of centipedes, Scutigeromorpha, in the Indian subcontinent. We used molecular phylogenetic analyses coupled with divergence time estimation on a novel dataset sampled from the Western Ghats, Eastern Ghats, and the Andaman Islands. We found that the Scutigeromorpha occupied four different parts of the global phylogeny under the subfamily Thereuoneminae - two were unidentified species, and the rest fell into two clades from the EG and WG, respectively. Aside from one of the unidentified species, all other specimens could be classified under the genus Thereuopoda. We also found evidence for geographic partitioning within as well as between the three biogeographic zones under study. From our dated phylogeny, we found that the Indian Scutigeromorpha are approximately 145 million years old, suggesting a Gondwanan origin. We also found further divergences within the clades, possibly signaling an ancient split between the WG and EG and subsequent genetic isolation due to wet forest fragmentation. Our study is the first to perform a phylogenetic reconstruction and biogeographic evaluation of the Scutigeromorpha from India. This will improve our understanding of Gondwanan biogeography and the ancient elements that have shaped the current species distribution of our country.
Keywords: Historical biogeography, Gondwana, Scutigeromorpha, Peninsular India, Molecular phylogenetic analysis, Divergence time estimation.
