Citation: Silva-Filho, A.G.S.; Mombert, A.; Nascimento, C.C.; Nóbrega, B.B.; Soares, D.M.M.; Martins, A.G.S.; Domingos, A.H.R.; Santos, I.; Della-Torre, O.H.P.; Perry, B.A.; et al. Eoscyphella luciurceolata gen. and sp. nov. (Agaricomycetes) Shed Light on Cyphellopsidaceae with a New Lineage of Bioluminescent Fungi. J. Fungi 2023, 9, 1004. https://doi.org/10.3390/ jof9101004 Academic Editor: Samantha C. Karunarathna Received: 17 July 2023 Revised: 22 August 2023 Accepted: 6 October 2023 Published: 12 October 2023 Copyright: © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). Fungi Journal of Article Eoscyphella luciurceolata gen. and sp. nov. (Agaricomycetes) Shed Light on Cyphellopsidaceae with a New Lineage of Bioluminescent Fungi Alexandre G. S. Silva-Filho 1 , Andgelo Mombert 2 , Cristiano C. Nascimento 1 , Bianca B. Nóbrega 3,4 , Douglas M. M. Soares 4 , Ana G. S. Martins 5 , Adão H. R. Domingos 5 , Isaias Santos 5 , Olavo H. P. Della-Torre 5 , Brian A. Perry 6 , Dennis E. Desjardin 7 , Cassius V. Stevani 3,4, * and Nelson Menolli, Jr. 1, * 1 IFungiLab, Departamento de Ciências da Natureza e Matemática (DCM), Subárea de Biologia (SAB), Instituto Federal de Educação, Ciência e Tecnologia de São Paulo (IFSP), Campus São Paulo (SPO), São Paulo 01109-010, SP, Brazil; silvafilhoags@gmail.com (A.G.S.S.-F.); cristiano.nascimento@ifpi.edu.br (C.C.N.) 2 Independent Researcher, 25640 Corcelle-Mieslot, France; mombertan@gmail.com 3 Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo 05508-000, SP, Brazil; bianca.barros.nobrega@usp.br 4 Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, São Paulo 05508-000, SP, Brazil; douglas@iq.usp.br 5 Instituto de Pesquisa da Biodiversidade (IPBio), Iporanga 18330-000, SP, Brazil; anaglaucia@ipbio.org.br (A.G.S.M.); henrique.domingos@ipbio.org.br (A.H.R.D.); tatubio@hotmail.com (I.S.); olavopetrucci@gmail.com (O.H.P.D.-T.) 6 Department of Biological Sciences, California State University, East Bay, Hayward, CA 94542, USA; brian.perry@csueastbay.edu 7 Department of Biology, San Francisco State University, San Francisco, CA 94132, USA; ded@sfsu.edu * Correspondence: stevani@iq.usp.br (C.V.S.); menollijr@yahoo.com.br (N.M.J.) Abstract: During nocturnal field expeditions in the Brazilian Atlantic Rainforest, an unexpected bioluminescent fungus with reduced form was found. Based on morphological data, the taxon was first identified as belonging to the cyphelloid genus Maireina, but in our phylogenetic analyses, Maireina was recovered and confirmed as a paraphyletic group related to genera Merismodes and Cyphellopsis. Maireina filipendula, Ma. monacha, and Ma. subsphaerospora are herein transferred to Merismodes. Based upon morphological and molecular characters, the bioluminescent cyphelloid taxon is described as the new genus Eoscyphella, characterized by a vasiform to urceolate basidiomata, subglobose to broadly ellipsoid basidiospores, being pigmented, weakly to densely encrusted external hyphae, regularly bi-spored basidia, unclamped hyphae, and an absence of both conspicuous long external hairs and hymenial cystidia. Phylogenetic analyses based on ITS rDNA and LSU rDNA support the proposal of the new genus and confirm its position in Cyphellopsidaceae. Eoscyphella luciurceolata represents a new lineage of bioluminescent basidiomycetes with reduced forms. Keywords: Agaricales; Basidiomycota; Brazilian biodiversity; bioluminescence; Niaceae 1. Introduction Agaricomycetes forms a large and diverse group that includes the mushroom-forming fungi and produces the most complex basidiomata forms, such as gilled mushrooms, bo- letes, polypores, and puffballs [1]. Some species of gilled mushroom are well known and stand out for their natural light emission with a luciferin/luciferase chemical reaction [2,3]. The bioluminescent fungi are morphologically well characterized and typically known for their gilled or poroid basidiomata within the order Agaricales [4]. The known biolumines- cent mushrooms are distributed in tropical and temperate regions, where they grow on moist decaying wood or leaves [4]. J. Fungi 2023, 9, 1004. https://doi.org/10.3390/jof9101004 https://www.mdpi.com/journal/jof