Perspectives into the value of genera, families and orders in classification

Abstract

This paper briefly discusses the history of fungal taxonomy and contributes to the concepts and the importance of ranking genera, families and orders. We propose recommendations for introducing species into appropriate ranks such as genera, families and orders, as well as the rationale to maintain species in one genus or segregate one genus into several genera. Various ways to rank fungi have commonly been based on morphological and phylogenetic species concepts. More recently, the use of molecular clocks, coupled with estimates of divergence times, has provided insights into how to assign species and support their establishment at different taxonomic hierarchical levels. Case studies are given from the order Botryosphaeriales and Pleosporales, and the genera Camarosporium, Colletotrichum, Diaporthe, Pestalotiopsis, Lophiostoma and Agaricus to demonstrate taxonomic ambiguities and the subjectivity in classification of fungi.

High-level classification of the Fungi and a tool for evolutionary ecological analyses

“…A number of reclassifications have been performed in Pucciniomycotina and Agaricomycotina to make the constituent orders and classes correspond to those in Ascomycota . Using divergence time in ranking taxa has recently gained popularity in mycology, but these studies focus on specific phyla, classes or lower-level taxa Liu et al 2016;Zhao et al 2016Zhao et al , 2017Hyde et al 2017).…”

Melansporellaceae: a novel family of Diaporthales (Ascomycota)

“…The status of the new family is supported by phylogenetic analysis of ITS and LSU sequence data. Establishing taxa at family and ordinal ranks are, however, often fraught with disagreement, as such ranking is usually subjective (Liu et al 2016, Samarakoon et al 2016a. It would be beneficial to establish the divergence times across the families of Diaporthales to establish if they fall within the range of other fungal families (see Phukhamsakda et al 2016, Samarakoon et al 2016b.…”

<p class="ZootaxaTitle">Hurdles in fungal taxonomy: Effectiveness of recent methods in discriminating taxa

“…Higher taxonomic ranks, such as classes, orders and families are not natural entities, but human constructs that are defined for the benefit of taxonomists (Laurin 2010;Liu et al 2016;Hyde et al 2017b). However, based on evolutionary aspects, there is an argument that these entities do naturally exist and the inability to recognize these evolutionary relationships has led to the conclusion of higher ranks being artificial human constructs (Ereshefsky 2007;Lücking 2019).…”

“…However, to date, there is no universal taxonomic criterion for defining higher ranks in fungal taxonomy (Samarakoon et al 2016). Even though mycologists have attempted to establish more reliable methods, it has always been contentious, subjective and resulted in unnecessary conflicts (Liu et al 2016;Divakar et al 2017;Hyde et al 2017b). For example, the three families namely Endomelanconiopsisaceae, Pseudofusicoccumaceae and Septorioideaceae were treated as genera pending further sampling and phylogenetic support by Liu et al (2016) due to their few morphological or ecological characters.…”

“…Even though mycologists have attempted to establish more reliable methods, it has always been contentious, subjective and resulted in unnecessary conflicts (Liu et al 2016;Divakar et al 2017;Hyde et al 2017b). For example, the three families namely Endomelanconiopsisaceae, Pseudofusicoccumaceae and Septorioideaceae were treated as genera pending further sampling and phylogenetic support by Liu et al (2016) due to their few morphological or ecological characters. However, Crous et al (2017) and Wijayawardene et al (2018a) accepted nine families including the above in Botryosphaeriales.…”