Taxonomic revision of Conobolbitina (Bolbitiaceae, Agaricales) based on collections from Jilin Province, China

Conobolbitina is a morphologically diverse transitional genus within the Bolbitiaceae. However, taxonomic confusion persists, as some of its species remain classified under other genera, and its section Verrucisporae has been recovered as paraphyletic. This study revises the subdivision of Conobolbitina using integrated morphological and phylogenetic analyses of specimens from Jilin Province, China.

A combined dataset of the internal transcribed spacer (ITS), nuclear large subunit ribosomal DNA (nrLSU), and translation elongation factor 1 - alpha (tef 1 - α) sequences was analyzed using maximum likelihood (ML) and Bayesian inference (BI). Phylogenetic results revealed four major monophyletic clades within Conobolbitina, corresponding to its four sections. In sect.

Conobolbitina, new combinations are proposed for two species, Con. sulcata and Con. striipes. In sect. Aeruginosa, Con. atrocyanea is newly combined.

For sect. Verrucisporae, its circumscription is revised by excluding the taxa responsible for its paraphyly, and a new combination, Con. australis, is proposed. To accommodate the excluded taxa from sect.

Verrucisporae, a new section, sect. Lignicola, is established based on morphological and phylogenetic evidence. Within this new section, three species, Con. glutinosa, Con. viscosa, and Con. sibirica, are newly combined, and two new species, Con. lignicola sp. nov. and Con. fuscoviolacea sp. nov., are described.

Through these revisions, the taxonomic positions of several species are clarified, and the paraphyly of sect. Verrucisporae is resolved. In total, this study revises and recognizes 10 new taxonomic entities, including one new section, two new species, and seven new combinations.

An identification key to the Chinese species of Conobolbitina is provided, along with morphological descriptions and line drawings for the two new species.