One step beyond a broad molecular phylogenetic analysis: Species delimitation of Adenomera marmorata Steindachner, 1867 (Anura: Leptodactylidae)

Abstract

Taxonomists always have had intense discussions about how species should be delimited and recently many studies have used integrative approaches by combining molecular, morphological, and bioacoustic data. Although these studies are paramount for understanding species diversity, few of them actually formalize species delimitations to the final step of nomenclatural acts. Historically, the Neotropical frog genus Adenomera has been considered as a difficult taxonomic group because it comprises many morphologically similar species exhibiting high levels of intraspecific polymorphism. A recent work using molecular data shed light on the phylogenetic relationships within the genus and identified several lineages that may correspond to undescribed species but did not delimit species boundaries. In the Atlantic Forest, a clade formed by A. marmorata and two putative species (Adenomera sp. J and Adenomera sp. K) were identified. In this paper, we combine morphological, acoustic, and molecular data in order to evaluate species limits within this Atlantic Forest Adenomera clade. We provide a redescription of A. marmorata and restrict its type locality to the Tijuca Massif, in the Municipality of Rio de Janeiro, Brazil. Our results do not support A. marmorata and the two candidate species as diagnosable distinct species. Therefore A. marmorata corresponds to a species with pronounced morphological and acoustic variation in the genus and a complex phylogeographic structure.

First karyotype description of the species of Adenomera Steindachner, 1867 (Anura, Leptodactylidae) in the “ thomei” clade

“…Adenomera marmorata shows a variation in chromosome pair 12, which is metacentric in the populations of the state of São Paulo. Thus, Campos et al (2009) hypothesized that it is an interpopulation variation, which was later confirmed by Cassini et al (2020) in a taxonomic study on the group that integrated DNA sequences, morphology, and bioacoustics. The specimen identified by Campos et al (2009) as A. aff bokermanni was collected in the municipality of Santa Branca in the state of São Paulo, which is outside the current distribution of A. bokermanni, which is restricted to the southern region of the state of Paraná (Cassini et al 2020).…”

“…The number of cytogenetic studies on anurans has grown in recent years (e.g., Ferro et al 2016 ; Gazoni et al 2018 ; Marciano-Jr et al 2021 ); however, information for some families and/or genera is still scarce. The genus Adenomera comprises common and abundant species, some of which often occur syntopically ( Cassini et al 2020 ), but cytogenetic data for the entire genus are still scant compared to other anuran genera. So far, only six of the 29 described species have been karyotyped.…”

“…To date, all information available regarding cytogenetic data within Adenomera populations is taxonomically inconclusive (e.g., Campos et al 2009 ). Nevertheless, these chromosome data provided support on taxonomic decisions on a broad study of species delimitation of Adenomera marmorata , which included DNA sequence, morphological, and bioacoustic data ( Cassini et al 2020 ). Thus, it is clear that further cytogenetic studies on the genus Adenomera will allow more robust conclusions regarding this taxonomically challenging group.…”

Anurans of a protected area from Mantiqueira Complex, Atlantic Forest of Minas Gerais state, Brazil

“…So, we carefully decided to register this species only at the genus level. Second, both genus Adenomera and Ischnocnema present a complex taxonomy (Gehara et al 2013, Cassini et al 2020 (Cruz & Peixoto, 1987) FA, CF 6, 14 Bokermannohyla circumdata (Cope, 1871) FA 13 Bokermannohyla ibitipoca (Caramaschi & Feio, 1990 molecular integrative approaches could elucidate the species complex hypothesis in both groups and arise with new candidate species or an accurate identification. For that reason, we prefer to assign both species only at the genus level.…”

New acoustic and molecular data shed light on the poorly known Amazonian frog Adenomera simonstuarti (Leptodactylidae): implications for distribution and conservation

“…Moreover, the only call description available is from the holotype in the original description, from which tissue samples were not collected (and neither were they collected from paratypes). It is important to highlight that species identification within Adenomera should be treated with caution in such cases which acoustic and/or molecular data are not available in a frog genus having a notably high number of undescribed and/or cryptic species (Carvalho & Giaretta 2013a;Fouquet et al 2014;Carvalho et al 2019b;Cassini et al 2020).…”