Three genomes of Osteoglossidae shed light on ancient teleost evolution

Osteoglossiformes is a basal clade of teleost, originated from late Jurassic and had seen the process of continental drift. The genomic differences amongst Osteoglossiformes species should reflect the unique evolve history of that time. Here, we presented the chromosome-level genome of which is the only omnivore species of Osteoglossidae spreading in Africa. Together with other two Osteoglossidae species genomes of and which spread in South America and Australia respectively, we found great evolutionary differences in gene families and transposable elements. Phylogenetic analysis showed that the ancestor of and diverged with at ∼106.1Mya, consistent with the time of Afro-South American drift and speciated from the ancestor of and at ∼59.2 Mya, consistent with the separation of Eurasia and North American continents. And we proposed the evolutionary traces of Osteoglossidae species based on comparative genomics analysis and their living geographic habitats. We identified loss of LINEs and LTRs, fast evolutionary rate in parallel to fast pseudogenization rate in and comparing to during the evolutionary process. We also found notable OR genes contraction in , which might be related to the diet transition. Taken together, we reconstructed the evolutionary process of Osteoglossidae using three representative genomes, providing a possible clue for biogeographic and evolution study of ancient teleost clade.