Looking under stones: A new Ctenomys species from the rocky foothills of the Sierras Grandes of central Argentina

Abstract

Ctenomys (tuco-tucos) is one of the most speciose genera of mammals, and the number of species that compose it continues to increase. Of the 65 species currently recognized for the genus, 15% have been described in the last 10 years. In this work, based on morphological and molecular evidence, we describe a new species of tuco-tuco for Central Argentina. This new species inhabits stony soils in the foothills of Sierras Grandes in Córdoba province and is distinguished from its congeners by a combination of anatomical characters, including a unique morphology of the posterolateral extension of the palatine. The molecular phylogeny based on the mitochondrial cytochrome b gene showed that this new species does not belong to any species complex described for Ctenomys. On the contrary, this new taxon shows a high genetic divergence with the rest of the species and species groups of Ctenomys and was recovered as an independent lineage within the phylogeny of the genus. This finding increases the richness of Ctenomys to 66 species. Our results highlight the need to increase the geographic sampling of studies in this genus to achieve a more complete understanding of its diversity.

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Journal of Mammalian Evolution (2023) 30:281–298
https://doi.org/10.1007/s10914-022-09634-4
ORIGINAL PAPER
Looking understones: Anew Ctenomys species fromtherocky
foothills oftheSierras Grandes ofcentral Argentina
FernandoJ.Mapelli1 · PabloTeta2 · FacundoContreras3 · DanielaPereyra1 · JoséW.Priotto3 ·
JoséA.Coda3
Accepted: 25 September 2022 / Published online: 22 October 2022
© The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2022
Abstract
Ctenomys (tuco-tucos) is one of the most speciose genera of mammals, and the number of species that compose it continues
to increase. Of the 65 species currently recognized for the genus, 15% have been described in the last 10years. In this work,
based on morphological and molecular evidence, we describe a new species of tuco-tuco for Central Argentina. This new
species inhabits stony soils in the foothills of Sierras Grandes in Córdoba province and is distinguished from its congeners
by a combination of anatomical characters, including a unique morphology of the posterolateral extension of the palatine.
The molecular phylogeny based on themitochondrial cytochrome b gene showed that this new species does not belong to any
species complex described for Ctenomys. On the contrary, this new taxon shows a high genetic divergence with the rest of
the species and species groups of Ctenomys and was recovered as an independent lineage within the phylogeny of the genus.
This finding increases the richness of Ctenomys to 66 species. Our results highlight the need to increase the geographic
sampling of studies in this genus to achieve a more complete understanding of its diversity.
Keywords Ctenomys· Tuco-tucos· Sierras Grandes· Central Argentina
Introduction
With 65 species, the genus Ctenomys Blainville, 1826
(commonly known as tuco-tucos) is one of the most diverse
within mammals (Bidau 2015; Burgin etal. 2018). These
subterranean rodents are distributed throughout southern
South America, occupying a wide variety of habitats but
always associated with friable and well-drained soils, where
their excavation activities produce conspicuous signals
(Busch etal. 2000; Freitas etal. 2021). Despite extensive
effort, the taxonomy of the genus Ctenomys remains poorly
resolved, and the number of species is still uncertain (Bidau
2015; Freitas 2016; D’Elía etal. 2021). Although several
synonyms have been proposed in recent years (Teta etal.
2020; Carnovale etal. 2021; D’Elía etal. 2021), the number
of species continues to increase due to the description of
new nominal forms (Freitas etal. 2012; Gardner etal. 2014;
Teta and D’Elía 2020; Brook etal. 2021).
The genus Ctenomys diversified rapidly during the Mid-
dle and Late Pleistocene (1.5–0.5 million years before pre-
sent) (De Santi etal. 2021; Verzi etal. 2021). Studies based
on biogeography, morphology, cytogenetics, and DNA
sequences identify some well-supported groups of species
(or species complexes) within this genus (Reig etal. 1990;
Massarini etal. 1991; D’Elía etal. 1999, 2021; Parada etal.
2011). Molecular studies show a polytomy at the base of the
phylogeny, reflecting the rapid and simultaneous diversifi-
cation of the different species complexes (Cook and Lessa
1998; Castillo etal. 2005; Parada etal. 2011; Carnovale
etal. 2021). Many of these complexes appear to have under-
gone simultaneously a second and more recent cladogenesis
* Fernando J. Mapelli
mapelli@gmail.com
1 Grupo de Genética y Ecología para la Conservación de la
Biodiversidad (GECoBi). División Mastozoología, Museo
Argentino de Ciencias Naturales “Bernardino Rivadavia”.
MACN-CONICET. Ciudad Autónoma de Buenos Aires,
BuenosAires, Argentina
2 División Mastozoología, Museo Argentino
de Ciencias Naturales “Bernardino
Rivadavia”. MACN-CONICET. Ciudad Autónoma de
Buenos Aires, BuenosAires, Argentina
3 Grupo de Investigación en Ecología Poblacional
y Comportamental (GIEPCO), Instituto de
Ciencias de La Tierra, Biodiversidad Y Ambiente
(ICBIA). UNRC-CONICET. Río Cuarto, Córdoba, Argentina
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