A little frog leaps a long way: compounded colonizations of the Indian Subcontinent discovered in the tiny Oriental frog genus Microhyla (Amphibia: Microhylidae)

PeerJ

article

Vladislav A. Gorin¹  Evgeniya N. Solovyeva²  Mahmudul Hasan³  Hisanori Okamiya⁴  D.M.S. Suranjan Karunarathna⁵  Parinya Pawangkhanant⁶  Anslem de Silva⁷  Watinee Juthong⁸  Konstantin D. Milto⁹  Luan Thanh Nguyen^1,10  Chatmongkon Suwannapoom⁶  Alexander Haas^1,11  David P. Bickford^1,12  Indraneil Das^1,13  Nikolay A. Poyarkov¹ 

[1] Faculty of Biology, Department of Vertebrate Zoology, Lomonosov Moscow State University;Zoological Museum, Lomonosov Moscow State University;Department of Fisheries, Bangamata Sheikh Fazilatunnesa Mujib Science & Technology University;Department of Biological Science, Faculty of Science, Tokyo Metropolitan University;Nature Explorations and Education Team;School of Agriculture and Natural Resources, University of Phayao;Amphibia and Reptile Research Organization of Sri Lanka;Prince of Songkla University;Zoological Institute, Russian Academy of Sciences;Asian Turtle Program—Indo-Myanmar Conservation;Center for Natural History, Universität Hamburg;Biology Department, University of La Verne;Institute of Biodiversity and Environmental Conservation, Universiti Malaysia Sarawak;Joint Russian-Vietnamese Tropical Research and Technological Center

关键词: Molecular phylogeny;    Biogeography;    Miniaturization;    Narrow-mouthed frogs;    Southeast Asia;    Microhylinae;    Species delimitation;    Indian collision;    Cryptic species;    Glyphoglossus;   

DOI  :  10.7717/peerj.9411

学科分类：社会科学、人文和艺术（综合）

来源: Inra

【 摘 要 】

Frogs of the genus Microhyla include some of the world’s smallest amphibians and represent the largest radiation of Asian microhylids, currently encompassing 50 species, distributed across the Oriental biogeographic region. The genus Microhyla remains one of the taxonomically most challenging groups of Asian frogs and was found to be paraphyletic with respect to large-sized fossorial Glyphoglossus. In this study we present a time-calibrated phylogeny for frogs in the genus Microhyla, and discuss taxonomy, historical biogeography, and morphological evolution of these frogs. Our updated phylogeny of the genus with nearly complete taxon sampling includes 48 nominal Microhyla species and several undescribed candidate species. Phylogenetic analyses of 3,207 bp of combined mtDNA and nuDNA data recovered three well-supported groups: the Glyphoglossus clade, Southeast Asian Microhyla II clade (includes M. annectens species group), and a diverse Microhyla I clade including all other species. Within the largest major clade of Microhyla are seven well-supported subclades that we identify as the M. achatina, M. fissipes, M. berdmorei, M. superciliaris, M. ornata, M. butleri, and M. palmipes species groups. The phylogenetic position of 12 poorly known Microhyla species is clarified for the first time. These phylogenetic results, along with molecular clock and ancestral area analyses, show the Microhyla—Glyphoglossus assemblage to have originated in Southeast Asia in the middle Eocene just after the first hypothesized land connections between the Indian Plate and the Asian mainland. While Glyphoglossus and Microhyla II remained within their ancestral ranges, Microhyla I expanded its distribution generally east to west, colonizing and diversifying through the Cenozoic. The Indian Subcontinent was colonized by members of five Microhyla species groups independently, starting with the end Oligocene—early Miocene that coincides with an onset of seasonally dry climates in South Asia. Body size evolution modeling suggests that four groups of Microhyla have independently achieved extreme miniaturization with adult body size below 15 mm. Three of the five smallest Microhyla species are obligate phytotelm-breeders and we argue that their peculiar reproductive biology may be a factor involved in miniaturization. Body size increases in Microhyla—Glyphoglossus seem to be associated with a burrowing adaptation to seasonally dry habitats. Species delimitation analyses suggest a vast underestimation of species richness and diversity in Microhyla and reveal 15–33 undescribed species. We revalidate M. nepenthicola, synonymize M. pulverata with M. marmorata, and provide insights on taxonomic statuses of a number of poorly known species. Further integrative studies, combining evidence from phylogeny, morphology, advertisement calls, and behavior will result in a better systematic understanding of this morphologically cryptic radiation of Asian frogs.

【 授权许可】

CC BY