Habitat preference modulates trans-oceanic dispersal in a terrestrial vertebrate

Abstract

The importance of long-distance dispersal (LDD) in shaping geographical distributions has been debated since the nineteenth century. In terrestrial vertebrates, LDD events across large water bodies are considered highly improbable, but organismal traits affecting dispersal capacity are generally not taken into account. Here, we focus on a recent lizard radiation and combine a summary-coalescent species tree based on 1225 exons with a probabilistic model that links dispersal capacity to an evolving trait, to investigate whether ecological specialization has influenced the probability of trans-oceanic dispersal. Cryptoblepharus species that occur in coastal habitats have on average dispersed 13 to 14 times more frequently than non-coastal species and coastal specialization has, therefore, led to an extraordinarily widespread distribution that includes multiple continents and distant island archipelagoes. Furthermore, their presence across the Pacific substantially predates the age of human colonization and we can explicitly reject the possibility that these patterns are solely shaped by human-mediated dispersal. Overall, by combining new analytical methods with a comprehensive phylogenomic dataset, we use a quantitative framework to show how coastal specialization can influence dispersal capacity and eventually shape geographical distributions at a macroevolutionary scale.

Genetic divergence of the Sunda ratsnake (Coelognathus subradiatus) across the Lesser Sunda Islands (Squamata: Colubridae)

“…While the higher-level taxonomic diversity of amphibians and reptiles within the archipelago is generally well documented, there are a number of widespread taxa that occur on islands or island-sets that are separated by oceanic barriers that have existed for millions of years. Some of these species that entered the archipelago early on have diversified and now represent species complexes (Reilly, 2016;Blom et al, 2019;Reilly et al, 2019a), while others have recently arrived and rapidly expanded through the archipelago (Reilly et al, 2017(Reilly et al, , 2019b). Here we examine the Sunda ratsnake (Coelognathus subradiatus), one of eight species of snake endemic to the Lesser Sundas ( fig.…”

Unexpectedly long survivorship on seawater of multiple coastal beetles indicates the possibility of “floating dispersal” for transoceanic migration

“…There are several types of transoceanic migration in insects, including scattering by wind (Compton 2002), drifting by ocean currents (Peck 1994), transport by birds and bats (Boedeker et al 2010;Suetsugu et al 2018) and artificial transportation by human activity (Holzapfel & Harrell 1968). Recent big data analysis of current dynamics and molecular phylogenetic works claim that current dispersal is one of the most realistic explanatory variables for transoceanic migration of land animals (Blom et al 2019;Fajardo et al 2019). Although there is little direct evidence of current dispersal in insects, there are many examples of range expansion across oceans (Trewick 2000;De Queiroz 2005;Yeh et al 2018); they have been explained mainly by "rafting" (Holzapfel & Harrell 1968;Gillespie et al 2012), which is the hitchhiking of terrestrial animals on the debris of trees and grasses caused by flood or tsunami.…”

A new giant sauropod,Australotitan cooperensisgen. et sp. nov., from the mid-Cretaceous of Australia

“…Faunal interchange between Asia and Australia evokes long distance oceanic dispersal, which at face value seems unlikely. However, recent analyses of terrestrial vertebrates demonstrates that long-distance dispersal over oceans is possible and can occur upwards of 100s to 1000s of kilometers between landmasses ( Blom et al, 2019 ; de Queiroz, 2005 ; Gerlach, Muir & Richmond, 2006 ; Hawlitschek, Ramirez Garrido & Glaw, 2017 ). In addition to these modern examples of faunal oceanic interchange, dinosaurs, including titanosaurians, have recently been proposed to have dispersed across oceanic barriers ( Longrich et al, 2021 ).…”