The spatio-temporal colonization and diversification across the Indo-Pacific by a ‘great speciator’ (Aves, Erythropitta erythrogaster)

Abstract

The Indo-Pacific region has arguably been the most important area for the formulation of theories about biogeography and speciation, but modern studies of the tempo, mode and magnitude of diversification across this region are scarce. We study the biogeographic history and characterize levels of diversification in the wide-ranging passerine bird Erythropitta erythrogaster using molecular, phylogeographic and population genetics methods, as well as morphometric and plumage analyses. Our results suggest that E. erythrogaster colonized the Indo-Pacific during the Pleistocene in an eastward direction following a stepping stone pathway, and that sea-level fluctuations during the Pleistocene may have promoted gene flow only locally. A molecular species delimitation test suggests that several allopatric island populations of E. erythrogaster may be regarded as species. Most of these putative new species are further characterized by diagnostic differences in plumage. Our study reconfirms the E. erythrogaster complex as a 'great speciator': it represents a complex of up to 17 allopatrically distributed, reciprocally monophyletic and/or morphologically diagnosable species that originated during the Pleistocene. Our results support the view that observed latitudinal gradients of genetic divergence among avian sister species may have been affected by incomplete knowledge of taxonomic limits in tropical bird species.

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Research
Cite this article: Irestedt M, Fabre P-H,
Batalha-Filho H, Jønsson KA, Roselaar CS,
Sangster G, Ericson PGP. 2013 The spatio-
temporal colonization and diversification across
the Indo-Pacific by a ‘great speciator’ (Aves,
Erythropitta erythrogaster). Proc R Soc B 280:
20130309.
http://dx.doi.org/10.1098/rspb.2013.0309
Received: 12 February 2013
Accepted: 8 March 2013
Subject Areas:
evolution, taxonomy and systematics, ecology
Keywords:
island biogeography, integrative taxonomy,
speciation, phylogeny, Pleistocene climate
changes
Author for correspondence:
Martin Irestedt
e-mail: martin.irestedt@nrm.se
Electronic supplementary material is available
at http://dx.doi.org/10.1098/rspb.2013.0309 or
via http://rspb.royalsocietypublishing.org.
The spatio-temporal colonization and
diversification across the Indo-Pacific by
a ‘great speciator’ (Aves, Erythropitta
erythrogaster)
Martin Irestedt1, Pierre-Henri Fabre3, Henrique Batalha-Filho4, Knud
A. Jønsson3,5, Cees S. Roselaar6, George Sangster2,7 and Per G. P. Ericson2
1
Department of Biodiversity Informatics and Genetics, and
2
Department of Vertebrate Zoology, Swedish
Museum of Natural History, PO Box 50007, 10405 Stockholm, Sweden
3
Center for Macroecology, Evolution and Climate at the Natural History Museum of Denmark,
University of Copenhagen, Copenhagen, Denmark
4
Departamento de Gene
´tica e Biologia Evolutiva, Instituto de Biocie
ˆncias, Universidade de Sa
˜o Paulo,
Sa
˜o Paulo, Brazil
5
Department of Life Sciences, Imperial College London, Silwood Park campus, Ascot SL5 7PY, UK
6
Naturalis Biodiversity Center, Darwinweg 2, PO Box 9517, 2300 RA Leiden, The Netherlands
7
Department of Zoology, Stockholm University, 10691 Stockholm, Sweden
The Indo-Pacific region has arguably been the most important area for the for-
mulationof theories about biogeography and speciation, but modern studies of
the tempo, mode and magnitude of diversification across this region are scarce.
We study the biogeographic history and characterize levels of diversificationin
the wide-ranging passerine bird Erythropitta erythrogaster using molecular, phy-
logeographic and population genetics methods, as well as morphometric and
plumage analyses. Our results suggest that E. erythrogaster colonized the
Indo-Pacific during the Pleistocene in an eastward direction following a step-
ping stone pathway, and that sea-level fluctuations during the Pleistocene
may have promoted gene flow only locally. A molecular species delimitation
test suggests that several allopatric island populations of E. erythrogaster may
be regarded as species. Most of these putative new species are further charac-
terized by diagnostic differences in plumage. Our study reconfirms the
E. erythrogaster complex as a ‘great speciator’: it represents a complex of up to
17 allopatrically distributed, reciprocally monophyletic and/or morphologi-
cally diagnosable species that originated during the Pleistocene. Our results
support the view that observed latitudinal gradients of genetic divergence
among avian sister species may have been affected by incomplete knowledge
of taxonomic limits in tropical bird species.
1. Introduction
The Indo-Pacific archipelagos have played a fundamental role in the formu-
lation of modern biogeographic and speciation theories. Observations of
the complex distributions of Asian and Australian faunas in the centre of the
region (present-day Wallacea) inspired Alfred Russell Wallace to develop his
ideas on the connection between geography and animal distributions [1,2].
Further east in Melanesia, patterns of geographical variation in birds formed
the basis of Ernst Mayr’s highly influential allopatric model of speciation [3].
A dynamic geological history [4] and Pleistocene sea-level fluctuations [5]
have generated complex patterns of spatio-temporal vicariance events and
dispersal routes [6]. Today, the Indo-Pacific archipelagos comprise more than
20 000 islands ranging from small atolls to large, geologically complex, tropical
islands, such as New Guinea, Sulawesi and Borneo. Several biodiversity hot-
spots have been recognized within the Indo-Pacific region [7], and the largest
island (New Guinea) is estimated to host the third-largest ‘high biodiversity’
wilderness in the world, only surpassed by the Amazon and Congo forests [8].
&2013 The Author(s) Published by the Royal Society. All rights reserved.