A monographic revision of the Neotropical dung beetle genus Sylvicanthon Halffter &amp; Martínez, 1977 (Coleoptera: Scarabaeidae: Scarabaeinae: Deltochilini), including a reappraisal of the taxonomic history of ‘Canthon sensu lato’

Mario Cupello,Fernando Z Vaz-De-Mello

doi:10.5852/ejt.2018.467

A monographic revision of the Neotropical dung beetle genus Sylvicanthon Halffter & Martínez, 1977 (Coleoptera: Scarabaeidae: Scarabaeinae: Deltochilini), including a reappraisal of the taxonomic history of ‘Canthon sensu lato’

Mario Cupello, Fernando Z Vaz-De-Mello

Open Access

https://doi.org/10.5852/ejt.2018.467

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Abstract

Although extensively studied by different authors over the past 150 years, the taxonomy of Canthon Hoffmannsegg, 1817 and allied genera (which are here informally referred to as ‘Canthon sensu lato’) still remains problematic. With the aim of resolving some of the questions surrounding these taxa, the present work reviews the taxonomy of one of them, the genus Sylvicanthon Halffter & Martínez, 1977. As defined here, Sylvicanthon is distributed mainly throughout the vast areas of tropical rainforests in the Neotropical region and includes 15 species divided into two groups: the enkerlini group, with a single species, S. enkerlini (Martínez et al., 1964) comb. nov., and the candezei group, with five subgroups: the candezei subgroup, with S. candezei (Harold, 1869), S. genieri sp. nov. and S. foveiventris (Schmidt, 1920); the aequinoctialis subgroup, with S. aequinoctialis (Harold, 1868) comb. nov. and S. proseni (Martínez, 1949) stat. et comb. nov.; the bridarollii subgroup, with S. bridarollii (Martínez, 1949), S. seag sp. nov., S. edmondsi sp. nov. and S. attenboroughi sp. nov.; the furvus subgroup, with S. furvus (Schmidt, 1920), S. monnei sp. nov., S. mayri sp. nov. and S. obscurus (Schmidt, 1920); and the securus subgroup, with a single species, S. securus (Schmidt, 1920) comb. nov. Three species originally included in Sylvicanthon are here (re)transferred to Canthon: Canthon xanthopus Blanchard, 1846 and C. machadoi (Martínez & Pereira, 1967) comb. nov., as well as C. cobosi (Pereira & Martínez, 1960) stat. et comb. nov., which had been previously in synonymy under C. xanthopus. Descriptions, redescriptions, illustrations and comparative tables on the external morphology (including the genital capsule) of the genus and its species are presented, as well as a detailed discussion on their biogeography, comparative morphology, hypotheses on their phylogenetic relationships, data on natural history and a detailed historical revision of the classification of ‘Canthon sensu lato’. Finally, we also discuss the so-called ‘species problem’ (i.e., the definition of the scientific term ‘species’) and its consequences to dung beetle taxonomy and favour the solution offered by the Biological Species Concept.

Highlights

As discussed elsewhere (Vaz-de-Mello & Cupello in press; Edmonds & Zídek 2012), the systematics of the New World dung beetles has witnessed a very active period of new landmark publications and unexpected findings, with a great number of modern taxonomic revisions published over the past 25 years
Either the type locality was the only known provenance (e.g., S. xanthopus, S. furvus, S. obscurus, S. securus comb. nov. and S. machadoi), or, due to misidentifications, what is regarded as the geographical range of a single widely-distributed species was, the distribution of a group of populations belonging to different species
As defined in the present work, Sylvicanthon has 15 species divided into two groups: the enkerlini group, with a single species, S. enkerlini, and the candezei group, with five subgroups: the candezei subgroup, with S. candezei, S. foveiventris and S. genieri sp. nov.; the aequinoctialis subgroup, with S. aequinoctialis and S. proseni; the furvus subgroup, with S. obscurus, S. furvus, S. monnei sp. nov. and S. mayri sp. nov.; the bridarollii subgroup, with S. bridarollii, S. attenboroughi sp. nov., S. edmondsi sp. nov. and S. seag sp. nov.; and the securus subgroup, with the sole S. securus

Summary

Introduction

As discussed elsewhere (Vaz-de-Mello & Cupello in press; Edmonds & Zídek 2012), the systematics of the New World dung beetles has witnessed a very active period of new landmark publications and unexpected findings, with a great number of modern taxonomic revisions published over the past 25 years (see Vaz-de-Mello & Cupello in press: table 1). We deal with the taxonomy of one of those small, poorly known deltochiline taxa, the genus Sylvicanthon Halffter & Martínez, 1977. Sylvicanthon was described by Halffter & Martínez (1977) to include five South American species placed in the genus Glaphyrocanthon Martínez, 1948: S. candezei (Harold, 1869) from the Amazon forest, S. xanthopus (Blanchard, 1846) from Bolivia, S. furvus (Schmidt, 1920) from Peru and Bolivia, S. bridarollii (Martínez, 1949) from Amazonia, and S. machadoi (Martínez & Pereira, 1967) known from a single locality in the Brazilian state of Pernambuco only. Either the type locality was the only known provenance (e.g., S. xanthopus, S. furvus, S. obscurus, S. securus comb. nov. and S. machadoi), or, due to misidentifications, what is regarded as the geographical range of a single widely-distributed species was, the distribution of a group of populations belonging to different species (as in the case of the distribution generally cited for S. candezei and S. bridarollii; see details below)

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