A novel multilocus phylogenetic estimation reveals unrecognized diversity in Asian horned toads, genus Megophrys sensu lato (Anura: Megophryidae)

The horned toad assemblage, genus Megophrys sensu lato, currently includes three groups previously recognized as the genera Atympanophrys, Xenophrys and Megophrys sensu stricto

Jin-Min Chen a,b,c,d, Wei-Wei Zhou b,d, Nikolay A. Poyarkov Jr. e,f, Bryan L. Stuart g, Rafe M. Brown h, Amy Lathrop i, Ying-Yong Wang j, Zhi-Yong Yuan k, Ke Jiang b,d, Mian Hou l, Hong-Man Chen b,d, Chatmongkon Suwannapoom m, Sang Ngoc Nguyen n, Tang Van Duong e,o, Theodore J. Papenfuss p, Robert W. Murphy b,i, Ya-Ping Zhang a,b,d,*, Jing Che b,d,*
a   State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming 650091, Yunnan, China
b   State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, Yunnan, China
c   Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming 650204, China
d   Southeast Asia Biodiversity Research Institute, Chinese Academy of Sciences, Menglun, Mengla, Yunnan 666303, China
e   Department of Vertebrate Zoology, Biological Faculty, Lomonosov Moscow State University, Leninskiye Gory, GSP-1, Moscow 119991, Russia
f   Joint Russian-Vietnamese Tropical Research and Technological Center under the A.N. Severtsov Institute of Ecology and Evolution RAS, South Branch, 3, Street 3/2, 10 District, Ho Chi Minh City, Viet Nam
g  North Carolina Museum of Natural Sciences, Raleigh, NC 27601, USA
h  Biodiversity Institute and Department of Ecology and Evolutionary Biology, 1345 Jayhawk Blvd, University of Kansas, Lawrence, KS 66045, USA
i   Centre for Biodiversity and Conservation Biology, Royal Ontario Museum, 100 Queen’s Park, Toronto, Ontario M5S 2C6, Canada
j   State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
k  College of Forestry, Southwest Forestry University, Kunming 650224, Yunnan, China
l   Institute of Continuing Education, Sichuan Normal University, Chengdu 610068, Sichuan, China
m  School of Agriculture and Natural Resources, University of Phayao, Phayao 56000, Thailand
n   Institute of Tropical Biology, Vietnam Academy of Science and Technology, 85 Tran Quoc Toan St., District 3, Ho Chi Minh 700000, Viet Nam
o   Vietnam National Museum of Nature, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Road, Hanoi, Viet Nam
p   Department of Integrative Biology, Museum of Vertebrate Zoology, University of California, Berkeley, CA 94720, USA

PubYear : 2017
Volume : 106
Publication Name : Molecular Phylogenetics and Evolution
Page number : 28-43

Abstract:
The horned toad assemblage, genus Megophrys sensu lato, currently includes three groups previously recognized as the genera Atympanophrys, Xenophrys and Megophrys sensu stricto. The taxonomic status and species composition of the three groups remain controversial due to conflicting phenotypic analyses and insufficient phylogenetic reconstruction; likewise, the position of the monotypic Borneophrys remains uncertain with respect to the horned toads. Further, the diversity of the horned toads remains poorly understood, especially for widespread species. Herein, we evaluate species-level diversity based on 45 of the 57 described species from throughout southern China, Southeast Asia and the Himalayas using Bayesian inference trees and the Generalized Mixed Yule Coalescent (GMYC) approach. We estimate the phylogeny using both mitochondrial and nuclear DNA data. Analyses reveal statistically significant mito-nuclear discordance. All analyses resolve paraphyly for horned toads involving multiple strongly supported clades. These clades correspond with geography. We resurrect the genera Atympanophrys and Xenophrys from the synonymy of Megophrys to eliminate paraphyly of Megophrys s.l. and to account for the morphological, molecular and biogeographic differences among these groups, but we also provide an alternative option. Our study suggests that Borneophrys is junior synonym of Megophrys sensu stricto. We provide an estimation of timeframe for the horned toads. The mitochondrial and nuclear trees indicate the presence of many putative undescribed species. Widespread species, such as Xenophrys major and X. minor, likely have dramatically underestimated diversity. The integration of morphological and molecular evidence can validate this discovery. Montane forest dynamics appear to play a significant role in driving diversification of horned toads.

Keywords: Atympanophrys, Borneophrys, Gene tree discordance, GMYC, Sympatric distribution, Xenophrys

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