Phylogeography of the Indo‐West Pacific maskrays (Dasyatidae, Neotrygon): a complex example of chondrichthyan radiation in the Cenozoic

• Published in: Ecology and evolution Vol. 3; no. 2; pp. 217 - 232
• Main Authors: Puckridge, Melody, Last, Peter R., White, William T., Andreakis, Nikos
• Format: Journal Article
• Language: English
• Published: England John Wiley & Sons, Inc 01.02.2013; Blackwell Publishing Ltd
• Subjects: Archipelagoes; Basins; Biodiversity; Biodiversity hotspot; Cenozoic; Chondrichthyes; cryptic species; Dasyatidae; Dasyatis; Deoxyribonucleic acid; Dispersal; Dispersion; DNA; marine speciation; maskray; Mitochondria; Neotrygon; Ocean basins; Original Research; Oscillations; Phylogeny; Phylogeography; Population; Population differentiation; Radiation; RAG1 protein; Speciation; Studies; Subgroups; Taeniura; Taxonomy; Topology; Variation; Eurasian Plate; ISW, Indian Ocean; Australia; IS, Tropical Pacific; Biodiversity hotspot; marine speciation; maskray; Neotrygon; cryptic species; phylogeography
• ISSN: 2045-7758; 2045-7758
• DOI: 10.1002/ece3.448

Maskrays of the genus Neotrygon (Dasyatidae) have dispersed widely in the Indo‐West Pacific being represented largely by an assemblage of narrow‐ranging coastal endemics. Phylogenetic reconstruction methods reproduced nearly identical and statistically robust topologies supporting the monophyly of the genus Neotrygon within the family Dasyatidae, the genus Taeniura being consistently basal to Neotrygon, and Dasyatis being polyphyletic to the genera Taeniurops and Pteroplatytrygon. The Neotrygon kuhlii complex, once considered to be an assemblage of color variants of the same biological species, is the most derived and widely dispersed subgroup of the genus. Mitochondrial (COI, 16S) and nuclear (RAG1) phylogenies used in synergy with molecular dating identified paleoclimatic fluctuations responsible for periods of vicariance and dispersal promoting population fragmentation and speciation in Neotrygon. Signatures of population differentiation exist in N. ningalooensis and N. annotata, yet a large‐scale geological event, such as the collision between the Australian and Eurasian Plates, coupled with subsequent sea‐level falls, appears to have separated a once homogeneous population of the ancestral form of N. kuhlii into southern Indian Ocean and northern Pacific taxa some 4–16 million years ago. Repeated climatic oscillations, and the subsequent establishment of land and shallow sea connections within and between Australia and parts of the Indo‐Malay Archipelago, have both promoted speciation and established zones of secondary contact within the Indian and Pacific Ocean basins. We used molecular phylogenetics and phylogeography to assess the evolutionary history of Neotrygon Maskrays (Dasyatidae) across the geologically and climatically dynamic tropical Indo‐West Pacific. Molecular clock approximations suggest that the group may have arrived in the region via tectonic rafting and dispersed across the tropics. Sharp genetic breaks recovered within Neotrygon kuhlii, N.  annotata, and, to a lesser extent, N. ningalooensis are indicative of multiple cryptic speciation events likely due to glacio‐eustatic sea‐level oscillations responsible for vicariant divergences.