TY - JOUR

T1 - Morphological and ecological convergence at the lower size limit for vertebrates highlighted by five new miniaturised microhylid frog species from three different Madagascan genera

AU - Scherz, Mark D.

AU - Hutter, Carl R.

AU - Rakotoarison, Andolalao

AU - Riemann, Jana C.

AU - Rödel, Mark-Oliver

AU - Ndriantsoa, Serge H.

AU - Glos, Julian

AU - Roberts, Sam Hyde

AU - Crottini, Angelica

AU - Vences, Miguel

AU - Glaw, Frank

N1 - Funding Information: AC is supported by an Investigador FCT grant from the Portuguese National Funds through FCT (Foundation for Science and Technology) grant IF/00209/2014. JCR, JG, M-OR and SHN were supported by the Deutsche Forschungsgemeinschaft (grant GL 665/1-1 and RO 3064/2-1). Fieldwork of FG and MV was supported by the Volkswagen foundation. MDS and MV were supported by the Deutsche Forschungsgemeinschaft (grant VE 247/13-1). No funders played any role in study design, data collection, analysis, or decision to publish. We are indebted to numerous individuals in the Direction Général des Forêts and Madagascar National Parks for providing us with permits to conduct the research associated with this study of the last 30 years, and export collected material. This study was carried out under collaboration accords with the Mention Zoologie et Biodiversité Animale (former Département de Biologie Animale), Université de Madagascar, and the Ministry for Environment and Forests of the Republic of Madagascar. Micro-CT scanning was facilitated by A. Cerwenka and B. Ruthensteiner. We wish to thank P. Bora, J. Müller, M. Puente, E. Rajeriarison, T. Rajoafiari-son, F. Randrianasolo, R.D. Randrianiaina, F.M. Ratsoavina, I. de la Riva, M. Teschke (née Thomas), D.R. Vieites, and C. Woodhead for their assistance in the field. Publisher Copyright: © 2019 Scherz et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

PY - 2019

Y1 - 2019

N2 - Miniaturised frogs form a fascinating but poorly understood amphibian ecomorph and have been exceptionally prone to taxonomic underestimation. The subfamily Cophylinae (family Microhylidae), endemic to Madagascar, has a particularly large diversity of miniaturised species which have historically been attributed to the single genus Stumpffia largely based on their small size. Recent phylogenetic work has revealed that several independent lineages of cophyline microhylids evolved towards highly miniaturised body sizes, achieving adult snout–vent lengths under 16 mm. Here, we describe five new species belonging to three clades that independently miniaturised and that are all genetically highly divergent from their relatives: (i) a new genus (Mini gen. nov.) with three new species from southern Madagascar, (ii) one species of Rhombophryne, and (iii) one species of Anodonthyla. Mini mum sp. nov. from Manombo in eastern Madagascar is one of the smallest frogs in the world, reaching an adult body size of 9.7 mm in males and 11.3 mm in females. Mini scule sp. nov. from Sainte Luce in southeastern Madagascar is slightly larger and has maxillary teeth. Mini ature sp. nov. from Andohahela in southeast Madagascar is larger than its congeners but is similar in build. Rhombophryne proportionalis sp. nov. from Tsaratanana in northern Madagascar is unique among Madagascar’s miniaturised frogs in being a proportional dwarf, exhibiting far less advanced signs of paedomorphism than other species of similar size. Anodonthyla eximia sp. nov. from Ranomafana in eastern Madagascar is distinctly smaller than any of its congeners and is secondarily terrestrial, providing evidence that miniaturisation and terrestriality may be evolutionarily linked. The evolution of body size in Madagascar’s microhylids has been more dynamic than previously understood, and future studies will hopefully shed light on the interplay between ecology and evolution of these remarkably diverse frogs.

AB - Miniaturised frogs form a fascinating but poorly understood amphibian ecomorph and have been exceptionally prone to taxonomic underestimation. The subfamily Cophylinae (family Microhylidae), endemic to Madagascar, has a particularly large diversity of miniaturised species which have historically been attributed to the single genus Stumpffia largely based on their small size. Recent phylogenetic work has revealed that several independent lineages of cophyline microhylids evolved towards highly miniaturised body sizes, achieving adult snout–vent lengths under 16 mm. Here, we describe five new species belonging to three clades that independently miniaturised and that are all genetically highly divergent from their relatives: (i) a new genus (Mini gen. nov.) with three new species from southern Madagascar, (ii) one species of Rhombophryne, and (iii) one species of Anodonthyla. Mini mum sp. nov. from Manombo in eastern Madagascar is one of the smallest frogs in the world, reaching an adult body size of 9.7 mm in males and 11.3 mm in females. Mini scule sp. nov. from Sainte Luce in southeastern Madagascar is slightly larger and has maxillary teeth. Mini ature sp. nov. from Andohahela in southeast Madagascar is larger than its congeners but is similar in build. Rhombophryne proportionalis sp. nov. from Tsaratanana in northern Madagascar is unique among Madagascar’s miniaturised frogs in being a proportional dwarf, exhibiting far less advanced signs of paedomorphism than other species of similar size. Anodonthyla eximia sp. nov. from Ranomafana in eastern Madagascar is distinctly smaller than any of its congeners and is secondarily terrestrial, providing evidence that miniaturisation and terrestriality may be evolutionarily linked. The evolution of body size in Madagascar’s microhylids has been more dynamic than previously understood, and future studies will hopefully shed light on the interplay between ecology and evolution of these remarkably diverse frogs.

U2 - 10.1371/journal.pone.0213314

DO - 10.1371/journal.pone.0213314

M3 - Journal article

C2 - 30917162

AN - SCOPUS:85063569036

VL - 14

JO - PLoS ONE

JF - PLoS ONE

SN - 1932-6203

IS - 3

M1 - e0213314

ER -