The taxonomic foundation, species circumscription and continental endemisms of Singerocybe: evidence from morphological and molecular data

Abstract

The genus Singerocybe (Tricholomataceae, Agaricales, Basidiomycota) has been the subject of controversy since its proposal in 1988. Its taxonomic foundation, species circumscription and geographical distribution have not yet been examined with molecular sequence data. In this study phylogenetic analyses on this group of fungi were conducted based on collections from Europe, eastern Asia, southern Asia, North America and Australia, with four nuclear markers, ITS, nrLSU, tef1-α and rpb2. Molecular phylogenetic analyses, together with morphological observations, strongly support Singerocybe as a monophyletic group and identify the vesicles in the pileal and stipe cuticle as a synapomorphy of this genus. Seven species are recognized in the genus, including one new species and four new combinations. Clitocybe trogioides and Clitocybe trogioides var. odorifera are synonyms of Singerocybe humilis and Singerocybe alboinfundibuliformis respectively. Most of these species are geographically restricted in their distributions. Furthermore our study expands the distribution range of Singerocybe from the North Temperate Zone to Australia (Tasmania) and tropical southern Asia.

• Allopatric speciation
• monophyly
• new combinations
• Singerocybe umbilicata
• synapomorphy

Acknowledgments

The authors are grateful for the help of Dr Barbara Thiers from the Herbarium of New York Botanic Garden (NYBG, USA); Dr Ronald H. Petersen from University of Tennessee Herbarium (TENN, USA); Dr Teruo Katsuyama from the Herbarium of Kanagawa Prefectural Museum of Natural History (KPM, Japan); Dr Yuki Mikanagi from the Herbarium of Natural History Museum and Institute (CBM, Japan); Prof Hua Peng and Dr En-De Liu from the Herbarium of Kunming Institute of Botany (KUN) for their kind help on loaning specimens. Prof Egon Horak (Austria), Dr P. Brandon Matheny (University of Tennessee, USA), Dr Matteo Gelardi (Italy), Ms. Beth Heap (Australia), Ms Atsuko Hadano, Mr Yuichi Taneyama (Japan), Dr Zai-Wei Ge, Dr Xiang-Hua Wang, Mr Qi Zhao, Ms Qing Cai and Ms Yan-Jia Hao (KUN) are thanked for providing valuable specimens and/or images. Thanks to Dr Harri Harmaja (Finland), Dr Matteo Gelardi and Prof Bellù Francesco (Italy), for their support and precious documentary material. Thanks also to Dr Jianping Xu (McMaster University, Canada), Dr Brian Perry (University of Hawaii, USA) and the two anonymous reviewers for their constructive comments and suggestions. This study was supported by the National Basic Research Program of China (No. 2014CB138305), the Joint Funds of the National Natural Science Foundation of China and Yunnan provincial government (No. U1302263) and the Hundred Talents Program of the Chinese Academy of Sciences.