Una Introducción a Los Mayores Sigmodontinos Vivientes: Revisión de Kunsia Hershkovitz, 1966 y Descripción de un Nuevo Género (Rodentia: Cricetidae)

A preliminary revision of Kunsia Hershkovitz, 1966 was made considering almost all the available specimens including type material of (in order of nomination) Mus principalis Lund, Scapteromys fronto Winge, S. gnambiquaræ M. Ribeiro, S. chacoensis Gyldenstolpe, and Kunsia fronto planaltensis Ávila-Pires. A new genus is proposed to allocate K. fronto and their subspecies. In addition, the latter are newly described and planaltensis is ranked as full species. The new genus is characterized by a unique combination of traits, including among others: large size, short tail (ca. 55% of combined head and body length), hispid dorsal hair, small tail scales covered by 3 hairs each one, rounded small-size ears, pes and manus unicolored, large nasals with acuminate posterior end reaching lacrimal level, distinctive zygomatic arch enlargement, large incisive foramina reaching first upper molar protocone, denticulate coronal suture open U-shaped, carotid circulatory pattern type 1, conspicuous coronal hypsodonty, developed mesolophids and protolophids + protoconulids in both first and second lower molars, first lower molar three rooted. Morphological comparisons of the new genus with Kunsia stricto sensu (restricted here to K. tomentosus) and Scapteromys (including S. aquaticus and S. tumidus) provide a basis for preliminary inferences about phylogenetic relationships. The fossil material from Bolivia and Argentina previously assigned to Kunsia is briefly addressed after a new study of the original remains, allowing us to conclude that they do not belong to the genus Kunsia neither to the new genus here proposed. The new genus is restricted to three recording localities in Brazil (one exclusively fossil) and one in Argentina, and had an unique record (Planaltina, Brasil) in the last five decades. Field work is urgently needed to assess the conservation status of these peculiar sigmodontine rodents.Se efectuó una revisión preliminar del género Kunsia Hershkovitz, 1966, empleando casi todos los especimenes disponibles e incluyendo el material tipo de las formas nominales (en orden de nominación): Mus principalis Lund, Scapteromys fronto Winge, S. gnambiquaræ M. Ribeiro, S. chacoensis Gyldenstolpe y Kunsia fronto planaltensis Ávila-Pires. Se propone un nuevo género para ubicar a K. fronto y sus subespecies. Adicionalmente, estas últimas son nuevamente descriptas y planaltensis es considerada como especie plena. El nuevo género se caracteriza por una combinación única de rasgos morfológicos, incluyendo entre otros: tamaño grande, cola corta (ca. 55% de la longitud cabeza-cuerpo combinados), pelaje dorsal híspido, escamas caudales pequeñas cubiertas por tres pelos cada una, orejas redondeadas y pequeñas, manos y pies unicolores, nasales largos posterioremente acuminados y alcanzando el nivel del lagrimal, ensanchamiento del arco cigomático, foramen incisivo largo alcanzando el protocono del primer molar superior, sutura coronal denticulada con forma de U, circulación carotídea de patrón 1, hipsodoncia coronal conspicua, mesolófidos y protolófidos + protoconúlidos desarrollados en los primeros y segundos molares inferiores, primer molar inferior con tres raíces. Las comparaciones morfológicas del nuevo género con Kunsia stricto sensu (restringido a Kunsia tomentosus) y Scapteromys (incluyendo S. aquaticus y S. tumidus) proveen una base para inferencias preliminares acerca de sus relaciones filogenéticas. El material fósil de Bolivia y Argentina previamente asignado a Kunsia es brevemente discutido sobre la base de un nuevo estudio a partir de los restos originales, concluyéndose que no pueden referirse ni al nuevo género aquí propuesto ni a Kunsia stricto sensu. El nuevo género está restringido a tres localidades en Brasil (una exclusivamente fósil) y una localidad en Argentina y tiene un único registro (Planaltina, Brasil) en las últimas cinco décadas. Se destaca la necesidad de urgentes trabajos de campo en orden de establecer el estatus de conservación de estos peculiares sigmodontinos

Pliocene sigmodontine rodents (Mammalia: Cricetidae) in northernmost South America: test of biogeographic hypotheses and revised evolutionary scenarios

We document the first occurrence of Sigmodontinae (Mammalia, Rodentia, Cricetidae) from the Pliocene of northern South America, from the San Gregorio Formation of northwestern Venezuela. The recovered isolated molars are identified as Oligoryzomys sp. and Zygodontomys sp., two currently widespread sigmodontines in South America. These records constitute the oldest representatives of these genera, potentially new species, and the first Pliocene occurrence for Oryzomyini and the whole subfamily outside Argentina. Hypotheses on the historical biogeography of sigmodontines have been constructed almost exclusively using genetic data and the fossils we report provide a new kind of evidence. The occurrence of Oligoryzomys sp. and Zygodontomys sp. in Venezuela provides novel information for the diversification models suggested for Oligoryzomys, by supporting a potential eastern corridor of open environments from northern to southern South America. The presence of sigmodontines from the locality home of the new reports, Norte Casa Chiguaje, is consistent with the palaeoenvironmental conditions originally proposed for it based on mammals and botanical records, being characterized as mixed open grassland/forest areas surrounding permanent freshwater systems. The new sigmodontine evidence is used to discuss the putative scenarios of the ancient evolution of the subfamily in South America, favouring a model in which open areas (savannahs) to the east of the Andes played crucial role aiding or obstructing Late Miocene-Pliocene sigmodontine dispersion southwards

Expert range maps of global mammal distributions harmonised to three taxonomic authorities

AimComprehensive, global information on species' occurrences is an essential biodiversity variable and central to a range of applications in ecology, evolution, biogeography and conservation. Expert range maps often represent a species' only available distributional information and play an increasing role in conservation assessments and macroecology. We provide global range maps for the native ranges of all extant mammal species harmonised to the taxonomy of the Mammal Diversity Database (MDD) mobilised from two sources, the Handbook of the Mammals of the World (HMW) and the Illustrated Checklist of the Mammals of the World (CMW).LocationGlobal.TaxonAll extant mammal species.MethodsRange maps were digitally interpreted, georeferenced, error-checked and subsequently taxonomically aligned between the HMW (6253 species), the CMW (6431 species) and the MDD taxonomies (6362 species).ResultsRange maps can be evaluated and visualised in an online map browser at Map of Life (mol.org) and accessed for individual or batch download for non-commercial use.Main conclusionExpert maps of species' global distributions are limited in their spatial detail and temporal specificity, but form a useful basis for broad-scale characterizations and model-based integration with other data. We provide georeferenced range maps for the native ranges of all extant mammal species as shapefiles, with species-level metadata and source information packaged together in geodatabase format. Across the three taxonomic sources our maps entail, there are 1784 taxonomic name differences compared to the maps currently available on the IUCN Red List website. The expert maps provided here are harmonised to the MDD taxonomic authority and linked to a community of online tools that will enable transparent future updates and version control

CAMBIOS EN LAS COMUNIDADES DE MICROMAMÍFEROS DURANTE EL HOLOCENO TARDÍO–ANTROPOCENO EN EL SUDESTE DE LA PROVINCIA DE BUENOS AIRES (ARGENTINA)

Se analiza la composición taxonómica cualitativa y cuantitativa de ensambles de micromamíferos (incluyendo didelfimorfos, quirópteros y roedores) generados por la acción trófica de aves estrigiformes. Estas muestras fueron coleccionadas en la localidad costera de Centinela del Mar (38° 26’ 18,56” S; 58° 13’ 17,42” O, General Alvarado, Buenos Aires, Argentina) y se escalonan, cronológicamente, para representar los últimos 500 años (i.e., Holoceno Tardío–Antropoceno). Desde aquella más antigua se registran la extinción local o regional de seis especies de roedores (i.e., Bibimys torresi, Ctenomys sp., Eligmodontia typus, Necromys lasiurus, Phyllotis sp. y Pseudoryzomys simplex) y la extinción biológica de un quiróptero (Desmodus draculae). En las muestras más recientes se verifica un incremento dramático del roedor Calomys sp. La comunidad de micromamíferos contemporánea es el resultado de la acción del impacto antrópico, en particular las actividades agrícolas de la última centuria actuando sobre un pool de especies pauperizado por los cambios climáticos del Holoceno Tardío (e.g., Óptimo Climático Medieval, Pequeña Edad del Hielo). Se discute la referencia previa de ensambles no-análogos para este tipo de asociaciones caracterizadas por la ocurrencia en simpatría de taxones actualmente alopátricos

Análisis de restos de roedores del sitio arqueológico Las Vueltas 1, Tierra del Fuego, Argentina

It is frequent to find the remains of several rodent species among the many archaeological sites of Northern Tierra del Fuego. However, the taphonomic interpretation of rodents is a complex issue, given that it is necessary to identify if these were incorporated into the archaeological assemblages through anthropic or natural action or agents. Yet, the identification of those assemblages that accumulated through human action or due to natural agents is an important issue given that only then we can infer the role that rodents had in human subsistence. In this article, we study rodent remains recovered from the archaeological site of Las Vueltas 1 (Isla Grande de Tierra del Fuego, Argentina); here rodents represented the second most common taxon present in the assemblage. A total of 2191 skeletal elements were recorded; 1488 remains belonged to the caviomorph, Ctenomys magellanicus, while 703 specimens belonged to at least four Cricetidae species. From a taphonomic perspective, a large number of the remains would have entered the archaeological assemblage through actions by raptors, carnivores, and as a result of natural death in burrows. Nevertheless, although to a lesser extent, there is also evidence of human consumption and discard of C. magellanicus.Diversas especies de roedores se encuentran con frecuencia en los sitios arqueológicos del norte de Tierra del Fuego. Sin embargo, discriminar las vías de incorporación en los contextos arqueofaunísticos y su potencialidad resulta una tarea ardua. La identificación de aquellos restos que ingresaron por acción antrópica o por agentes naturales resulta necesaria para poder inferir el rol que tuvieron en la subsistencia humana. En este trabajo se estudian los restos de roedores del sitio arqueológico Las Vueltas 1 (Isla Grande de Tierra del Fuego, Argentina), donde representan el segundo taxón más abundante en la muestra. Se identificaron un total de 2191 elementos esqueletarios; 1488 corresponden al caviomorfo Ctenomys magellanicus y 703 a representantes de la familia Cricetidae, con al menos 4 especies. La interpretación tafonómica efectuada sugiere un origen múltiple; buena parte del material parece haber ingresado por la acción acumuladora de aves rapaces y cánidos y también por incorporación natural a través de muerte en madrigueras. No obstante y aunque en menor grado, hay evidencias de consumo y descarte antrópico en C. magellanicus

Juliomys Gonzalez 2000

Juliomys González, 2000 Type species. Juliomys pictipes (Osgood, 1933). Included species (in order of nomination). J. pictipes (Osgood, 1933), J. rimofrons Oliveira and Bonvicino, 2002; J. ossitenuis Costa, Pavan, Leite and Fagundes, 2007. Emended diagnosis. Small to medium Sigmodontinae rodents (total length ~ 200, Occipto-nasal length ~ 27) with large head, conspicuous eyes, and tail equal or slightly larger than head and body; dorsal pelage soft dark-brown to light-orange brown; feet rather short and broad with 6 plantar pads and scutelated surface; skull with short rostrum (<35 % Occipto-nasal length), rounded braincase, and rather posterior domed profile; nasals divergent forward; interlacrymal depression behind nasals; anterior portion of interfrontal suture with incomplete fusion or directly slit-like fontanelle; zygomatic plate nearly vertical with almost obsolete upper free border; coronal suture V-shaped; interparietal wide; occipital region reduced; mesopterygoid fossa lireshaped with anterior border located at the level of third molar protocone; robust opisthodont upper incisors; brachyodont molars with crested coronal topography and well developed anteromedian flexus/ids and mesolophs/ids; 8 mammae. Fossil record. No fossil of Juliomys is known.Published as part of Pardiñas, Ulyses F. J., Teta, Pablo, D'Elía, Guillermo & Galliari, Carlos, 2008, Rediscovery of Juliomys pictipes (Rodentia: Cricetidae) in Argentina: emended diagnosis, geographic distribution, and insights on genetic structure, pp. 29-44 in Zootaxa 1758 on pages 32-33, DOI: 10.5281/zenodo.18185