DOI: 10.3897/vz.76.e190575

Authors: Pamela Sánchez-Vendizú, Andrés Parada, Pablo Teta, Marcial Quiroga-Carmona, Pablo Jayat, Raisa Cairampoma, César Medina, Jay F. Storz, Guillermo D’Elía

Abstract: Abstract Mito-nuclear discordance is a well-recognized phenomenon; however, the limited use of nuclear data in rodent systematics has revealed few documented cases. As such, the extent to which discordant gene trees mislead taxonomic schemes remains unclear. Here, we document an example of such discordance in a taxonomic assessment of species boundaries within the subgenus Angelomys of the genus Abrothrix, based on mitochondrial, nuclear (ultraconserved elements, UCEs), and morphological data. Our analyses revealed strong discordance between the mitochondrial tree and the species tree emerging from the UCE dataset. The latter recovered three main lineages within Angelomys, each phenotypically distinct. Therefore, we propose that the taxonomic scheme that best represents the alpha taxonomy of the subgenus Angelomys recognizes three species rather than the two recently proposed. The three species we recognize are Abrothrix (Angelomys) andina, distributed from the highlands of Santiago in central Chile northward along the Pacific coast to southern Peru; Ab. (An.) dolichonyx, a highland species ranging from Mendoza in west central Argentina northward through the high Andean regions of northern Argentina, northern Chile, western Bolivia and southern Peru; and Ab. (An.) olivacea, distributed from lowland areas of central Chile and Mendoza (Argentina), extending southward through the temperate forests, Patagonia, Tierra del Fuego, nearby islands, and reaching Cape Horn. Finally, we designate a lectotype for Hesperomys dolichonyx (= Ab. dolichonyx) and restricted the type locality of Mus andinus (= Ab. andina) to a locality within the general area indicated in the species description and from which the species has been recorded.

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DOI: 10.3897/vz.76.e187462

Authors: Pablo Teta, Agustina A. Ojeda, Andrea P. Tarquino Carbonell, J. Raquel Alvarado-Larios, Pablo Cuello, Paula Cornejo, Julián Mignino, Ricardo A. Ojeda, Diego H. Verzi

Abstract: Abstract Octodontidae is a moderately speciose family (seven genera and 16 species) of South American caviomorph rodents; however, from an ecological point of view, it is a diverse clade that includes terrestrial, cursorial, scansorial, and fossorial to strictly subterranean forms. Its distribution is mostly restricted to the western portion of southern South America, on both sides of the Andes. Here we describe a new living genus and species of Octodontidae, whose distribution is restricted to the Sierra de Guasapampa (central Argentina). Phylogenetic analysis of mitochondrial molecular markers (cytochrome b) recovers this taxon as sister to Octomys; the genetic distance observed between them is similar to the range of distances found between other genera of Octodontidae (>9%). This, together with its morphological divergence from Octomys in the context of Octodontidae, supports its treatment as a separate genus. This rodent is characterized by a unique combination of morphological features, including a long and very hairy tail; grayish brown dorsal coloration, which contrasts against the whitish belly; robust skull, with a proportionally short rostrum; wide interorbital region, with slightly divergent supraorbital edges; proportionally wide incisive foramina; orbitosphenoid with its origin displaced to the basisphenoid; inflated but small auditory bullae; median lacerate foramen not covered by the bulla; and upper molariform lobes with acuminate labial tips. Specimens of the new genus and species were captured on rocky slopes with abundant bromeliad vegetation in the understory. This finding highlights the importance of continuing field research, especially in areas that have not previously been surveyed.

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DOI: 10.3897/vz.76.e173627

Authors: Diego A. Caraballo, Denise H. Campo, Pablo Teta, Cecilia Lanzone

Abstract: Abstract Species delimitation in recently evolving taxa presents unique challenges. Such taxa may not have accumulated enough genetic or morphological differences to be easily distinguished using traditional methods, while processes such as incomplete lineage sorting or gene flow may obscure these distinctions. One paradigmatic recently evolved taxon is the Corrientes group of the subterranean genus Ctenomys (Rodentia, Ctenomyidae), a set of populations with different chromosomal forms occurring in the homonymous province of Argentina. Previously, three nominal species and several independently evolving lineages had been proposed; however, a comprehensive integrative approach—including qualitative and quantitative morphological analyses, as well as additional molecular proxies for lineage delimitation—was still lacking, and these results had not been evaluated in a taxonomic context. In this study, we added new lines of evidence, including Bayesian phylogenetics and divergence time estimation, haplotype networks, and genetic distances. We integrated this information with karyotypic and microsatellite data to discuss previously proposed lineages, as well as to analyze the evolutionary processes that shaped the history of this group. Finally, we analyzed the qualitative and quantitative morphology of individuals from the nominal species and a chromosomally derived lineage, and we propose a revised species-level and infraspecific classification for this complex group of rodents. This resulted in the delimitation of two species, C. roigi and C. perrensi, the latter being subdivided into three subspecies: Ctenomys perrensi perrensi, C. perrensi dorbignyi, and C. perrensi iberaensis subsp. nov. In addition, other identified lineages, such as Sarandicito, Manantiales, and Santa Rosa, deserve future taxonomic investigation.

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DOI: 10.3897/vz.76.e180973

Authors: Oleg V. Brandler, Andrey R. Tukhbatullin, Svetlana Y. Kapustina, Sergey N. Matveevsky, Fatimat A. Tembotova, Andrey Y. Puzachenko

Abstract: Abstract The systematics of blind mole rats (Spalacinae), a group of highly specialized subterranean rodents, remain a subject of debate. Within the genus Spalax, the greater blind mole rat (Spalax microphthalmus) is distinguished by its unique diploid chromosome number (2n = 60 versus 2n = 62 in others) and the most extensive geographic range. However, its intraspecific variation has been insufficiently studied. Previous finding of specimens with 2n = 62 in the North Caucasus were attributed to chromosomal polymorphism within S. microphthalmus. In this study, we conducted a comprehensive analysis of morphometric, morphological, molecular, and chromosomal variation across the entire range of S. microphthalmus, integrated with a comparative analysis of the genus Spalax. Our results demonstrate that the North Caucasian populations (2n = 62) exhibit consistent species-level differences in molecular genetics (from 8% to 12% divergence in cyt b), karyotype, and cranial morphology, distinguishing them from S. microphthalmus and all other congeners. This lineage also possesses a unique combination of morphological traits, including features that bring it closer to the hypothetical common ancestor of all modern Spalax species. Based on this integrative evidence, we describe this lineage as a new species: Spalax lyapunovae sp. nov., increasing the number of extant Spalax species to nine. This newly recognized species, endemic to the central North Caucasus, requires further ecological and distributional studies. Given its presumably limited range, an urgent assessment of its conservation status is warranted.

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DOI: 10.3897/vz.76.e194570

Authors: Raquel Alvarado-Larios, Pablo Teta, Pablo Cuello, J. Pablo Jayat, Andrea P. Tarquino-Carbonell, Guillermo D'Elia, Paula Cornejo, Agustina A. Ojeda

Abstract: The genus Ctenomys Blainville, 1826 includes 68 living species of small to medium-sized (100-1200 g) caviomorph rodents of subterranean habits. During the last decade, this genus has been the subject of numerous taxonomic studies, including the description of new species and the proposal of novel synonyms. Based on phylogenetic analysis of mitochondrial DNA sequences and qualitative and quantitative morphological traits, here we review the species boundaries of the tuco-tucos of the species group of C. mendocinus and describe a new species. The new species is morphologically distinct from other phylogenetically and geographically close species of Ctenomys (e.g., C. fochi, C. mendocinus), showing several differences in their craniodental traits (e.g., proportionally longer nasals and less globose tympanic bullae). The new species occurs in montane grasslands and shrublands of northwestern Mendoza (ca. 2,710 m a.s.l.) and in lowlands (ca. 1,000 m a.s.l.) of the Monte Desert ecoregion in an area highly impacted by accelerated processes associated with the wine industry.

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DOI: 10.3897/vz.76.e194750

Authors: Uwe Fritz

Abstract: NO ABSTRACT

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DOI: 10.3897/vz.76.e194752

Authors: Uwe Fritz

Abstract: No Abstract

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DOI: 10.3897/vz.76.e180962

Authors: Nikoleta Dubjelová, Tereza Hadravová, Martin Ivanov, Ivan Horáček

Abstract: The European Pleistocene populations of the narrow-headed vole (Stenocranius gregalis), an index species of the Palearctic glacial communities, were recently found to differ from the extant Asian species by a deep genetic divergence and are to be considered a separate species, Stenocranius anglicus, which had to persist through the interglacial stages in local European refugia. Here, we analyze over 2000 first lower molars from 14 stratified localities in the Czech Republic and Slovakia, spanning the Middle Pleistocene to Holocene, employing geometric morphometrics, biometric measurements, and morphotype classifications to assess molar shape variation. Our results demonstrate persistent morphological variability, with particularly high morphotype diversity during MIS 5–3, followed by simplification and reduced variance in post–LGM populations. Morphological divergence was greater among geographic localities than stratigraphic stages, suggesting strong regional and ecological influences. Stratified sequences reveal diverse evolutionary trajectories from long-term morphological stability in refugia to gradual simplification preceding extinction in the early Holocene. These patterns align with broader Eurasian trends but also highlight regionally specific responses to climatic and ecological change accompanying the species’ extinction dynamics during the early to middle Holocene. The paper underscores the importance of integrating detailed morphometrics with stratigraphic and ecological evidence to shed light on these topics.

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DOI: 10.3897/vz.74.e128528

Authors: Jorge Brito, Rubí García, Francisco X. Castellanos, Gabriela Gavilanes, Jenny Curay, Julio C. Carrión-Olmedo, Daniela Reyes-Barriga, Juan M. Guayasamin, Jorge Salazar-Bravo, C. Miguel Pinto

Abstract: Abstract The Andean cloud forests of Ecuador are home to numerous unique mammals. Rodents of the tribe Thomasomyini are particularly abundant in many Andean localities, with Thomasomys – the largest genus in the subfamily Sigmodontinae (51 species) – especially species-rich and diverse. Despite recent advances on the systematics of the genus, where seven species have been described in the last five years, there is tantalizing evidence that its true diversity remains completely understood. Over the course of approximately ten years of fieldwork in Ecuador, a significant number of Thomasomys specimens were collected from various localities in both, the eastern and western Andean ranges. Through an extensive genetic study of these specimens, augmented with what is available in public databases, we argue that there exist at least 20 undescribed species in the genus, with no less that twelve potential new species in Ecuador alone. In this paper, we describe two of these species belonging to the group cinereus, one recently collected and the other previously referred to as Thomasomys sp. 1; further, we present an updated cyt b gene tree of the genus. The gene tree includes at least 56 valid and putative species and supports the monophyly of the genus, while at the same time suggest a paraphyletic “aureus” group. Our findings suggest that the genus likely exhibits additional hidden diversity in significant portions of Colombia, Peru, and Bolivia which calls for the need for a comprehensive reassessment of the entire genus. The recognition of these two new species brings the total number of known Thomasomys to 53 species, 19 of which occur in Ecuador, including 17 that are endemic to this country.

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DOI: 10.3897/vz.74.e133467

Authors: Arlo Hinckley, Jesús E. Maldonado, Noriko Tamura, Jennifer A. Leonard, Melissa T. R. Hawkins

Abstract: Abstract We present a comprehensive integrative taxonomic review of Callosciurus caniceps and Tamiops mcclellandii as they are currently defined. This review combines published molecular evidence, craniodental morphometrics, pelage and bacular variation, evaluations of potential hybrid zones using museum specimens and citizen science photographs, and, for C. caniceps, bioacoustic evidence. Our findings lead to the recognition of two species that had been lost in synonymy and highlight future perspectives on species delimitation in Sciuridae. By comparing phenotypic differentiation across climatic and vegetation transitions and contextualizing our results with the evolutionary history of our study systems, we provide insights into distribution, ecogeographical patterns, and speciation drivers in Southeast Asian vertebrates.

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DOI: 10.3897/vz.74.e115242

Authors: Raquel Alvarado-Larios, Pablo Teta, Pablo Cuello, J. Pablo Jayat, Andrea P. Tarquino-Carbonell, Guillermo D’Elía, Paula Cornejo, Agustina A. Ojeda

Abstract: Abstract The genus Ctenomys Blainville, 1826 includes 68 living species of small to medium-sized (100–1200 g) caviomorph rodents of subterranean habits. During the last decade, this genus has been the subject of numerous taxonomic studies, including the description of new species and the proposal of novel synonyms. Based on phylogenetic analysis of mitochondrial DNA sequences and qualitative and quantitative morphological traits, here we review the species boundaries of the tuco-tucos of the species group of C. mendocinus and describe a new species. The new species is morphologically distinct from other phylogenetically and geographically close species of Ctenomys (e.g., C. fochi, C. mendocinus), showing several differences in their craniodental traits (e.g., proportionally longer nasals and less globose tympanic bullae). The new species occurs in montane grasslands and shrublands of northwestern Mendoza (ca. 2710 m a.s.l.) and in lowlands (ca. 1000 m a.s.l.) of the Monte Desert ecoregion in an area highly impacted by accelerated processes associated with the wine industry.

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DOI: 10.3897/vz.73.e101065

Authors: Pablo Teta, J. Pablo Jayat, Raquel Alvarado-Larios, Agustina A. Ojeda, Pablo Cuello, Guillermo D’Elía

Abstract: The genus Ctenomys of subterranean rodents is one of the most species-rich genera of Mammalia, with 66 living species currently recognized. However, the taxonomy of the genus is dynamic with several new species and new synonymies proposed during the last decade. One of the species groups that have undergone more changes in contents in the last years is the Ctenomys mendocinus species group. Here, based on phylogenetic analysis of mitochondrial DNA sequences and qualitative and quantitative morphological evidence, we conducted an appraisal of the species richness of tuco-tucos of the C. mendocinus species group, describing two new species from west-central Argentina. The new taxa are morphometrically distinctive when compared with other geographically or phylogenetically close species of the genus, showing qualitative differences in their craniodental anatomy. One of the new species is known from the eastern Andean slopes of La Rioja and San Juan provinces, occurring on montane grasslands and shrublands above 3,500 m a.s.l., while the other is endemic of southwestern Mendoza province, occurring on montane grasslands and shrublands between 2,400–2,700 m a.s.l. In addition, we include for the first time the nominal forms C. fochi and C. validus in a phylogenetic analysis of the genus Ctenomys, showing that both correspond to the C. mendocinus species group, being the second a junior synonym of C. mendocinus. Finally, we made some comments about other candidate species within this species group as well as highlight issues that need to be addressed to gain a robust picture of the specific richness of Ctenomys.

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DOI: 10.3897/vz.73.e96656

Authors: Diego H. Verzi, Nahuel A. De Santi, A. Itatí Olivares, Cecilia C. Morgan, Néstor G. Basso, Federico Brook

Abstract: The subterranean rodent Ctenomys is the most polytypic South American mammal genus and one of the most speciose and rapidly diversifying mammal genera in the world. Its systematics is unstable due to the underlying accelerated diversification processes that give rise to evolutionary lineages at different stages of differentiation and to remarkable morphological homogeneity even among long-differentiated species. As a result, species boundaries are often difficult to define. Diversity of this genus in the coastal area of central Argentina has been extensively studied, with two independent lineages currently recognized while a distinct third population had not been previously detected. Through a phylogenetic analysis based on combined morphological and molecular evidence, Bayesian estimates of divergence times, and morphometric and morphological assessments, we recognize this third population as an independently evolving lineage. The new species, Ctenomys pulcer sp. nov., is here described for both the living fauna and the fossil record of the Pampean region of central Argentina. According to phylogenetic results, Ctenomys pulcer sp. nov. belongs to the essentially Patagonian magellanicus clade, and would have diverged from its sister species, Ctenomys bidaui, during the middle Pleistocene (ca. 0.4 Ma). Its current distribution in the fixed and semifixed dunes of the coastal Pampean region is assumed to represent a relict of a wider and continuous distribution of potentially suitable environments during the late Pleistocene. Ctenomys pulcer sp. nov. occurs in a particularly fragile natural system subjected to profound disturbances caused by diverse anthropic actions and therefore measures for the conservation of its habitat will be indispensable.

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DOI: 10.3897/vz.73.e94111

Authors: Willem G. Coetzer

Abstract: The greater cane rat (Thryonomys swinderianus) is an African rodent with a wide Sub-Saharan distribution range. This species is viewed as an important protein source in many African countries. These rodents are also regularly viewed as a pest species who frequently raid croplands in agricultural settings. No phylogenetic work has to date been published on T. swinderianus from southern Africa. This paper therefore reports the first phylogenetic assessment on the species across the South African distribution range. Thirty samples were sourced from local museum collections, with one direct submission by a member of the public who found a rodent carcass identified as T. swinderianus west of its known distribution range in the Eastern Cape Province of South Africa. Two mitochondrial loci previously used in West African studies of this species were used in the current study to asses T. swinderianus population genetic diversity and phylogenetic structure across the South African distribution. A comparison to sequence data from West Africa was also performed. A divergence time estimation was conducted to further investigate the evolutionary history of the South African sub-population. Similar genetic diversity estimates were observed for the South African sub-population when compared to the West African datasets. Specimens from the eastern parts of South Africa showed higher genetic diversity estimates, possibly indicative of an initial colonisation site from eastern Africa. Two distinct phylogenetic clades were identified by Bayesian inference, forming distinct West African and South African groups. The divergence estimates showed similar ages for the T. swinderianus most recent common ancestor (MRCA) as previously reported. The MRCA estimates for the South African group identified a possible middle to late Pleistocene migratory event from eastern African into southern Africa. Further fine scale sampling across the African distribution range is however needed to provide more accurate assessments for future conservation management planning for the different sub-populations, as needed.

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DOI: 10.3897/vz.72.e90474

Authors: Zainab Dashti, Hasan Alhaddad, Bader H. Alhajeri

Abstract: Populations of broadly distributed species often exhibit geographic structuring, which is sometimes reflected in phenotype. The monotypic Indian gerbil (Tatera indica) is an example of a widely distributed species, with its range encompassing much of Asia. This study aims to determine if T. indica populations exhibit marked variation in skull morphology—this structure is particularly adaptable and thus could be amenable to show such variation. Furthermore, the potential drivers of skull variation are examined, including the role of climate and geography. To achieve these goals, 21 linear measurements were measured on the skulls of 509 specimens, coming from 111 different localities, across this species wide range. The specimens were then assigned into one of four broad geographic groups (≈ populations) based on their geographic proximity, and the overall and the pairwise differences in the 21 skull measurements among these groups were assessed. Specimens from Pakistan significantly differed from those belonging to the West Iran, East Iran, and India populations, which in turn did not significantly differ from each other. Pairwise bioclimatic and geographic distances between the localities explained a significant, yet small amount of variation in the measurements. Thus, while the Pakistani T. indica population was distinct in skull measurements, both climatic and non-climatic spatial factors seem not to account largely for its distinctiveness (from the other populations).

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DOI: 10.3897/vz.71.e68897

Authors: Emmanuel Matamba, Leigh R. Richards, Michael I. Cherry, Ramugondo V. Rambau

Abstract: Abstract South African small mammals are under-represented in DNA barcoding efforts, particularly from the eastern forested regions of the country. This study reports DNA barcoding of Rhabdomys taxa from previously unsampled parts of the Eastern Cape and KwaZulu-Natal provinces of South Africa. The complete mitochondrial DNA cytochrome oxidase I (COI) gene was sequenced for 101 Rhabdomys sp. individuals from 16 localities from all three main forest groups (coastal, mistbelt, and scarp forests). Molecular data were supplemented with external morphological measurements, including those deemed potential taxonomically diagnostic characters. Findings indicate the area to be inhabited solely by Rhabdomys dilectus chakae. Haplotypes distributed across the three forest groups were separated by shallow sequence divergences ranging from 0.001–0.015 (Kimura 2-parameter model) and displayed very little population genetic structure (FST= 0.071787). Morphological data revealed some regional metric differences in external morphology, but all the head-and-body to tail (HB: tail) ratios match that of R. d. chakae, and consequently, molecular and morphological data are congruent. These data confirm a range extension of R. d. chakae, supporting the utility of COI barcodes in the identification of small mammalian species.

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