[BioGeography / Herpetology • 2014] Crossing the Line: Increasing Body Size in a trans-Wallacean Lizard Radiation (Cyrtodactylus, Gekkota)

Figure 1. Dated phylogeny (Bayesian MCC tree) for Cyrtodactylus estimated with concatenated nuclear and mitochondrial dataset showing divergence dates and ancestral state reconstructions for body length (blue smallest, green intermediate and red largest); taxon names and posterior probabilities are given in the electronic supplementary material, figure S1; exact ages and sizes of all nodes (with 95% highest posterior density (HPD) intervals) are in electronic supplementary material, file SI_4. Yellow shading denotes the two clades occurring in the Australopapuan region. Grey bars at right denote maximum body size for each species (in mm), with grey shading denoting larger-bodied clades in Asian and Australopapuan regions.

DOI: 10.1098/rsbl.2014.0479

Abstract

The region between the Asian and Australian continental plates (Wallacea) demarcates the transition between two differentiated regional biotas. Despite this striking pattern, some terrestrial lineages have successfully traversed the marine barriers of Wallacea and subsequently diversified in newly colonized regions. The hypothesis that these dispersals between biogeographic realms are correlated with detectable shifts in evolutionary trajectory has however rarely been tested. Here, we analyse the evolution of body size in a widespread and exceptionally diverse group of gekkotan lizards (Cyrtodactylus), and show that a clade that has dispersed eastwards and radiated in the Australopapuan region appears to have significantly expanded its body size ‘envelope’ and repeatedly evolved gigantism. This pattern suggests that the biotic composition of the proto-Papuan Archipelago provided a permissive environment in which new colonists were released from evolutionary constraints operating to the west of Wallacea.

Keywords: Asia; Cyrtodactylus; ecological release; insular gigantism; New Guinea; Wallace's Line

Paul M. Oliver, Phillip Skipwith and Michael S. Y. Lee. 2014. Crossing the Line: Increasing Body Size in a trans-Wallacean Lizard Radiation (Cyrtodactylus, Gekkota). Biology Letters. DOI: 10.1098/rsbl.2014.0479

https://www.academia.edu/8701155/Oliver_P.M._Skipwith_P._Lee_M.S.Y._2014._Crossing_the_line_increasing_body_size_in_a_n_lizard_radiation_Cyrtodactylus_Gekkota_._Biology_Letters_10_20140479

Geckos crossed the line and got bigger

http://www.earthtimes.org/scitech/geckos-crossed-line-bigger/2715/

http://www.apscience.org.au/projects/APSF_11_1/apsf_11_1.html

http://www.ibtimes.co.uk/new-guinea-geckos-evolving-into-giants-embargo-00-01-wednesday-hold-jk-1468918

[PaleoOrnithology • 2014] Ancient DNA reveals Elephant Birds and Kiwi are Sister Taxa and Clarifies Ratite Bird Evolution

A Kiwi and an Elephant Bird egg.

by: Kyle Davis & Paul Scofield, Canterbury Museum
phenomena.nationalgeographic.com

The evolution of the ratite birds has been widely attributed to vicariant speciation, driven by the Cretaceous breakup of the supercontinent Gondwana. The early isolation of Africa and Madagascar implies that the ostrich and extinct Madagascan elephant birds (Aepyornithidae) should be the oldest ratite lineages. We sequenced the mitochondrial genomes of two elephant birds and performed phylogenetic analyses, which revealed that these birds are the closest relatives of the New Zealand kiwi and are distant from the basal ratite lineage of ostriches. This unexpected result strongly contradicts continental vicariance and instead supports flighted dispersal in all major ratite lineages. We suggest that convergence toward gigantism and flightlessness was facilitated by early Tertiary expansion into the diurnal herbivory niche after the extinction of the dinosaurs.

A) The break-up of Gondwana into separate continents. B) The ratite family tree, as you’d predict from the rafting hypothesis. C) The actual ratite family tree.

DOI: dx.doi.org/10.1126/science.1251981

  

Mitchell, Llamas, Soubrier, Rawlence, Worthy, Wood, Lee & Cooper. 2014. Ancient DNA reveals Elephant Birds and Kiwi are Sister Taxa and Clarifies Ratite Bird Evolution. Science. 344: 898-900. DOI: dx.doi.org/10.1126/science.1251981

academia.edu/7128252/Mitchell_Llamas_Soubrier_Rawlence_Worthy_Wood_Lee_and_Cooper._2014._Ancient_DNA_reveals_elephant_birds_and_kiwi_are_sister_taxa_and_clarifies_ratite_bird_evolution._Science_344_898-900

http://phenomena.nationalgeographic.com/2014/05/22/the-surprising-closest-relative-of-the-huge-elephant-birds/