Victor Manuel Bravo Cuevas | Universidad Autonoma del Estado de Hidalgo (original) (raw)

Papers by Victor Manuel Bravo Cuevas

Research paper thumbnail of THE RECORD OF CAMELIDS (ARTIODACTYLA, CAMELIDAE) FROM THE VALSEQUILLO BASIN, LATE PLEISTOCENE OF PUEBLA STATE, CENTRAL MEXICO: TAXONOMY, DIET, AND GEOGRAPHIC DISTRIBUTION

– Dental and postcranial fossil material referable to camelids, which has been recovered from Qua... more – Dental and postcranial fossil material referable to camelids, which has been recovered from Quaternary deposits that outcrop in the Valsequillo Basin, Puebla State, central Mexico, is formally described. A comparative study indicates the presence of two species of camelids, including Hemiauchenia macrocephala and Camelops hesternus. The sample referable to H. macrocephala includes maxillary and mandibular fragments, isolated teeth, and several postcranial remains (astragalus, metapodials, and proximal phalanges), which show the following diagnostic features of the species: molariforms covered by a layer of cementum; a mandible increasing in depth from p4 to m3; p4 triangular in outline; long and slender metapodials; and proximal phalanges with a W-shaped suspensory ligament scar. The sample referable to C. hesternus is represented by maxillary and mandibular fragments, isolated teeth, and metapodials, sharing with the species its large size; P4 quadrate in outline; p4 triangular in outline and simply folded; and a mandible that is significantly deeper from p4 to m3. A microwear analysis was performed in order to characterize the diet of studied samples, indicating a browser and mixed feeding behavior in H. macrocephala and C. hesternus respectively. The differences in size and trophic regimes in these species should explained the resource partitioning between them. In the late Pleistocene these camelids were common in Mexican sites between the 19°-25° N, and the record from the Valsequillo Basin is one of the few sites where both species have been reported.

Research paper thumbnail of Canid Coprolites from the Late Pleistocene of Hidalgo, Central Mexico: Importance for the Carnivore Record of North America

We present the first reported occurrence of canid coprolites from the late Pleistocene of central... more We present the first reported occurrence of canid coprolites from the late Pleistocene of central Mexico. The sample consists of five associated coprolites recovered from Quaternary deposits that crop out in southeastern Hidalgo, central Mexico. The material shows several of the typical features of canid feces, including elongated cylindrical shape, uncommon and nondistinct constrictions, and one tapered end. The coprolites are similar in size to feces of North American foxes, such as Vulpes macrotis, V. lagopus, V. vulpes, and Urocyon cinereoargenteus; likewise, their size might be comparable to those of the Pleistocene canid Canis cedazoensis. The content of the studied coprolites consists of numerous teeth and bone fragments referable to the pocket gophers Pappogeomys or Cratogeomys. The coprolite content is related to a mostly carnivorous diet comparable to that of C. cedazoensis, wolves (Canis lupus, C. rufus, and C. dirus), and some foxes (V. macrotis and V. velox). As a result, it is proposed that the potential trace maker of the coprolites could be a form similar to a carnivorous fox or a small dog. These trace fossils represent the first indirect evidence of canids in the late Pleistocene of Hidalgo and provide additional information regarding the geographic distribution of the Canidae in temperate areas of North America that now are part of central Mexico during the second half of the Pleistocene.

Research paper thumbnail of First occurrence of Panthera atrox (Felidae, Pantherinae) in the Mexican state of Hidalgo and a review of the record of felids from the Pleistocene of Mexico

Panthera atrox was a common large-sized cat in North America during the late Pleistocene. An isol... more Panthera atrox was a common large-sized cat in North America during the late Pleistocene. An isolated lower canine and a fifth metacarpal bone referable to this species were recovered from fluvial Quaternary deposits that outcrop in southeastern Hidalgo, central Mexico. Associated fossil material belonging to Bison indicates a Rancholabrean North American Land Mammal Age; the age assignment is corroborated by the presence of P. atrox. A comparative study with selected specimens of Panthera and Smilodon indicates that the Hidalgoan sample shares the following diagnostic features with P. atrox: a large, robust, and non-strongly curved lower canine; a large and relatively slender fifth metacarpal with a well-developed projection on the palmar side at the proximal end, narrow articulating surface for the unciform; a narrow notch on the articulating surface for the fourth metacarpal; and a diaphysis that at the middle is oval in cross section. The record supplements the evidence of P. atrox in central Mexico and represents the first reported occurrence of this cat species in the state of Hidalgo. By the same token, the known geographic distribution of P. atrox in the Mexican territory suggests that it was relatively common in temperate areas of central Mexico between 19 and 24 • N at an altitudinal range from 1500 to 2250 m a.s.l. The large size (mean body mass of 300 kg) and hypercarnivorous adaptations of the American lion suggest it was the top predator of the mammalian community recorded at southeastern Hi-dalgo, displacing other members of the carnivore guild at the mesopredator level, such as the dire wolf (Canis dirus), which has been also reported in the area. The high diversity of large herbivores recorded at southeastern Hidalgo, which in turn could represent potential prey of P. atrox, suggests that some areas that now are part of central Mexico were suitable hunting sites for this large-sized cat. A review of the Pleistocene record of Felidae from Mex-ico revealed that it encompasses 87.5 and 73.3 % of generic and specific diversity known for North America,

Research paper thumbnail of Repartición 
de 
recursos 
en 
una 
asociación 
de
 mamíferos 
del 
Pleistoceno
 tardio 
del 
Estado
 de
 Hidalgo

La evaluación del sobrelapamiento de nicho basado en el hábito alimentario de organismos reciente... more La evaluación del sobrelapamiento de nicho basado en el hábito alimentario de organismos recientes, permite conocer la repartición de recursos en una comunidad. En este trabajo se implementó en una asociación de mamíferos pleistocénicos del estado de Hidalgo, usando datos de [δ]13C con los cuales se categorizó el hábito alimentario de los taxones: Hemiauchenia gracilis, Camelops sp., Mammut americanum, Cuvieronius sp., Paramylodon cf. harlani, Odocoileus cf. virginianus, Capromeryx minor, Equus conversidens, Mammuthus sp. y Bison cf. antiquus. Se establecieron categorías dietarias con base en el consumo de plantas C4 por taxón: 1. Pacedor estricto (> 90%); 2. Pacedor variable (75% - 90%); 3. Dieta mixta C4 (60% - 75%); 4. Dieta mixta (40% - 60%); 5. Dieta mixta C3 (25% - 40%); 6. Ramoneador variable (10% - 25%); 7. Ramoneador estricto (< 10%). El sobrelapamiento de nicho se estableció mediante el análisis de Modelos Nulos utilizando el programa EcoSim. Con fines de comparación, se implementó la misma estrategia en una comunidad de mamíferos actual en Kenia y en una asociación fósil del Pleistoceno de Bolivia. Los resultados muestran que la mayoría de los mamíferos de la asociación de Hidalgo tuvieron un comportamiento dietario amplio. Por otra parte, se observa que el consumo de plantas C4 de H. gracilis, M. americanum, O. cf. virginianus y Cuvieronius sp. fue semejante (valor de similitud > 0.9), esto sugiere una mayor competencia por los recursos entre estas especies. La información disponible indica que la coexistencia de los mamíferos de Hidalgo estuvo regulada por su capacidad de consumir plantas C3/C4 en cantidades diferenciales y sólo en algunas formas es probable que la competencia halla sido más intensa, lo cual es congruente con el bajo grado de sobrelapamiento de nicho observado (p = 0.10). Un resultado semejante se obtuvo para la comunidad de mamíferos de Kenia y diferente en la de Bolivia; en esta última la competencia por los recursos fue elevada.

Research paper thumbnail of Dieta y Hábitat De Los Caballos Pleistocénicos De Hidalgo y Tlaxcala Mediante El Análisis De Isótopos Estables Δ13C y Δ18O

Research paper thumbnail of Reconstruyendo ambientes antiguos: análisis de isótopos estables

El análisis de isótopos estables en restos fósiles se ha convertido en una herramienta sumamente ... more El análisis de isótopos estables en restos fósiles se ha convertido en una herramienta sumamente utilizada en la reconstrucción de ambientes que existieron hace miles de años. Se aplica este método para caracterizar el hábito alimentario en organis- mos extintos y su utilidad en la interpretación paleoambiental. La información generada evidencia los cambios que ha manifestado la biósfera en estructura, composición, abundancia y diversidad como resultado de las modificaciones ambientales a lo largo del intervalo considerado de la historia de la Tierra, lo cual a su vez tiene implicaciones en la conservación biológica.

Research paper thumbnail of Feeding Ecology of Astrohippus stockii from the Late Hemphillian of Central Mexico: Stable Carbon Isotopes Analysis and Dental Wear Patterns

BioOne sees sustainable scholarly publishing as an inherently collaborative enterprise connecting... more BioOne sees sustainable scholarly publishing as an inherently collaborative enterprise connecting authors, nonprofit publishers, academic institutions, research libraries, and research funders in the common goal of maximizing access to critical research.

Research paper thumbnail of Mammut americanum from the Pleistocene of Hidalgo Description of mastodons (Mammut americanum) from the late Pleistocene of southeastern Hidalgo, central Mexico

Fossil specimens of American mastodons (Mammut americanum) that have been recovered from fluvial ... more Fossil specimens of American mastodons (Mammut americanum) that have been recovered from fluvial sedimentary deposits of the late Pleistocene of southeastern Hidalgo, central Mexico, are formally described. The sample includes cranial and postcranial remains of an adult male that represents one of the most complete mastodons that have been found in Mexico, as well as a molar belonging to an old individual. The material from Hidalgo shows the following diagnostic features of M. americanum: well-developed tusks that curved upward; upper and lower molars with a simple occlusal pattern; last molars with four to five lophs/ids; a medial sulcus between the lophs/ids; a scapula with a straight caudal border, a short and expanded neck, and a glenoid cavity that is oval in outline; a short and robust humerus with a prominent epicondylar crest; a radius with a wide distal end; and an ulna with a well-developed olecranon process and a deep trochlear notch. The dental size of the mastodon from Hidalgo is comparable to that of mastodons from the Gulf Coastal Plain and the Great Lakes region, whereas the limb dimensions are similar to those of the Watkins Glen Mastodon from the late Pleistocene of New York. In order to characterize the diet and habitat of the mastodons from Hidalgo, a stable carbon and oxygen isotope analysis in tooth enamel apatite was performed. The results indicate that studied specimens were mainly C3 browsers (mean δ 13 C isotope value of-10.06 ‰) that thrived in closed habitats covered by high vegetation, such as trees (mean δ 18 O isotope value of-4.31 ‰). This information suggests the presence of closed habitats in the southeastern region of Hidalgo, during the second half of the Pleistocene. Resumen Se describen formalmente ejemplares de mastodontes Americanos (Mammut americanum) recuperados de depósitos sedimentarios fluviales del Pleistoceno tardío del sureste de Hidalgo, centro de México. La muestra incluye elementos craneales y postcraneales pertenecientes a un macho adulto, el cual representa uno de los mastodontes más completos encontrados en México; así como un molar aislado perteneciente a un individuo viejo. El material de Hidalgo muestra las siguientes características diagnósticas de M. americanum: defensas bien desarrolladas que se curvan hacia arriba; molares superiores e inferiores con un patrón oclusal simple; últimos molares con cuatro a cinco lofos/idos; un surco medial entre los lofos/idos; escápula con un borde caudal recto, cuello corto y expandido, así como con una cavidad glenoidea de forma ovalada; húmero corto y robusto con una cresta epicondilar prominente; radio expandido en su extremo distal; y ulna con un proceso olecraneal bien desarrollado que sobresale de la diáfisis, así como con un surco troclear profundo. El tamaño de los elementos dentales del mastodonte de Hidalgo es comparable con el de mastodontes de la Planicie Costera del Golfo y la región de los Grandes Lagos, mientras que las dimensiones de los huesos de las extremidades son similares con las del Mastodonte Watkins Glen del Pleistoceno tardío de Nueva York. Por otra parte, se realizó un análisis de isótopos estables de carbono y oxígeno en esmalte dental para caracterizar la dieta y el hábitat de los mastodontes de Hidalgo. Los resultados de este análisis indican que los ejemplares estudiados fueron ramoneadores de plantas C3 (valor promedio de δ 13 C de-10.06 ‰) y que

Research paper thumbnail of Dietary analysis of Late Cenozoic Mexican equids from three different geographic/geologic settings using stable carbon isotopes: Coincidences, differences and paleobiologic significance

The development of Vertebrate Paleontology in Mexico is uneven, so that there is a strong bias in... more The development of Vertebrate Paleontology in Mexico is uneven, so that there is a strong bias in favor of Neogene/Quaternary mammals largely collected in the Trans-Mexican Volcanic Belt (TMVB hereafter) and Central Plateau (CeP hereafter) Morphotectonic Provinces [MP hereafter]; however, the time is ripe for pursuing research in other than taxonomic areas. Here we investigate C 3 /C 4 plant consumption in the equid lineage in three such provinces, which provide different geographic/geologic and paleoecologic scenarios during the Barstovian, Hemphillian and Rancholabrean times. Our results show that the Barstovian equids from Oaxaca, Sierra Madre del Sur MP Cormohipparion aff. C. quinni, Merychippus cf. M. sejunctus and Pliohippus sp. largely fed on C 3 plants, which were the chief food stuff of horses in Mexico, particularly in the Southeast. On the other hand, the Hemphillian equid from Guanajuato, CeP Astrohippus stocki, was an unbalanced C 3 /C 4 mixed feeders in favor of C 4 plants, a fact that indicates a profound plant diversification due to the inception and rapid diversification of C 4 plants that occurred there at this time, as it occurred in temperate North America, resulting in the differential consumption of C 4 plants over that of C 3 plants. Such trend prevailed until the Rancholabrean, as born out by the inferred diet for Equus conversidens and Equus sp. from Hidalgo, TMVB. Clearly then, the coeval diet change observed in Mexico and temperate North America implies a correlative vegetation change resulting in the appearance and rapid diversification of C 4 plants, which largely formed the preferred food stuff of equids since the Hemphillian, although some C 3 plant consumption was maintained till the Rancholabrean. It should be noted that the development of hypsodonty in equids and many artiodactyls, has long been interpreted as the adaptive mammalian response to the new feeding conditions.

Research paper thumbnail of The record of Cenozoic horses in Mexico: current knowledge and palaeobiological implications

Fossil horses in Mexico have been documented for 150 years. At present, there exists an abundant ... more Fossil horses in Mexico have been documented for 150 years. At present, there exists an abundant and diverse record that deserves consideration. In this contribution, we offer an overview of the current knowledge on the fossil hors- es in Mexico. The Mexican record of the family Equidae in- cludes early horses and representatives of the subfamilies Anchitheriinae and Equinae. The diversity of horses in Mexico includes 15 genera and 28 species with ages ranging from early Eocene to late Pleistocene. The record of the sub- family Equinae from the upper Neogene and Quaternary de- posits from central Mexico represents the largest proportion of fossil horse evidence in the country. Of the species observed within the Mexican territory, 75 % were at their southernmost extent in North America. The Mexican record shows that a considerable portion of the evolutionary history of horses occurred in Mexico. Nevertheless, the study of fossil horses in Mexico is ongoing. Therefore, including the Mexican
specimens in studies using biogeographical, evolutionary and ecological approaches will considerably improve our knowledge of horses in southern North America.

Research paper thumbnail of First reported occurrence of Palaeolama mirifica (Camelidae, Lamini) from the Late Pleistocene (Rancholabrean) of Puebla, central Mexico

Palaeolama was a relatively rare camelid in North America during the Pleistocene. Here we report ... more Palaeolama was a relatively rare camelid in North America during the Pleistocene. Here we report the first occurrence of P. mi- rifica in the Late Pleistocene of Puebla, central Mexico. This is the southernmost record of P. mirifica in North America, and fills in a geographic gap with a record of the species in Costa Rica. The fossil-bearing unit is composed of silt, fine sand, and scarce pebbles. This unit is partially correlative with the alluvial sequence of Axamilpa, Puebla, considered to be MIS 2 – 3 in age. Isotopic data and Mesowear III values indicate that P. mirifica from Barranca Xocoa was an intermediate feeder.

Research paper thumbnail of Reconstruyendo ambientes antiguos: análisis de isótopos estables

C I E N C I A e r g o -s u m , ISSN 1405-0269, V o l . 21-3, noviembre 2014-febrero 2 0 15. Unive... more C I E N C I A e r g o -s u m , ISSN 1405-0269, V o l . 21-3, noviembre 2014-febrero 2 0 15. Universidad Autónoma del Estado de México, Toluca, México. Pp. 237-242.

Research paper thumbnail of A roe deer from the Pliocene of Hidalgo, central Mexico

Cuevas, V.M. 2015. A roe deer from the Pliocene of Hidalgo, central Mexico. Acta Palaeontologica ... more Cuevas, V.M. 2015. A roe deer from the Pliocene of Hidalgo, central Mexico. Acta Palaeontologica Polonica 60 (4): 807-813.

Research paper thumbnail of A summary of the Mesozoic vertebrate tracks of Mexico

Dinosaurs and other reptiles from the Mesozoic Mexico

Research paper thumbnail of Taxonomy and notes on the paleobiology of the late Pleistocene (Rancholabrean) antilocaprids (Mammalia, Artiodactyla, Antilocapridae) from the state of Hidalgo, central Mexico

Revista Mexicana de Ciencias Geológicas

A set of cranial and dental material of Antilocapridae was recovered from Quaternary deposits tha... more A set of cranial and dental material of Antilocapridae was recovered from Quaternary deposits that outcrop in southeastern Hidalgo, central Mexico. The fossil bearing unit consists of clay, silt, sand, and scarce conglomeratic lenses in a fluvial environment; the specimens are associated with Bison indicating a Rancholabrean Land Mammal Age. The comparative study of the material with selected specimens of North American antilocaprids, allowed its identification as the small-sized species Capromeryx minor and the medium-sized Stockoceros conklingi. The sample referable to C. minor shows a combination of cranial and dental characters typical of this species, including a large posterior tine that is curved upward and forward, posterior horn core with a deep sulcus on its posterior side that extends from the base to the tip, and well-developed heel on M3. The isotopic analysis of teeth referable to this species from Hidalgo indicates a mixed feeding dietary behavior. A partial skull and associated horn core fragments were assigned to Stockoceros conklingi, considering its larger size than C. minor and shorter than the extant pronghorn Antilocapra americana, as well as for having symmetrical and diverging horn cores, and more outwardly flaring horn cores. The recognition of these antilocaprids in southeastern Hidalgo represents one of the southernmost occurrences within temperate North America. The tiny Capromeryx minor is known in North American localities of lower altitude (0-100 m a.s.l.) compared to those of the medium-sized Stockoceros conklingi . Hence, body size differences between both species and altitude differences between some of their localities suggests minimal direct competition between these antilocaprids.

Research paper thumbnail of Darwin y Wallace: Los niveles a los que ocurre la Selección Natural

Herreriana Revista de Divulgación de la Ciencia (Número Especial Darwin 2009)

La selección natural es una fuerza evolutiva, causa principal de la adaptación biológica en las p... more La selección natural es una fuerza evolutiva, causa principal de la adaptación biológica en las poblaciones. También es responsable del surgimiento de las adaptaciones, entendidas como caracteres fenotípicos que tienen una función específica en los organismos que las poseen .

Research paper thumbnail of Descubriendo el pasado remoto de Hidalgo

Herreriana Revista de Divulgación de la Ciencia

La relativa pequeñez del territorio hidalguense contrasta con su variedad de paisajes y riqueza h... more La relativa pequeñez del territorio hidalguense contrasta con su variedad de paisajes y riqueza histórica; por supuesto nos referimos a la historia natural de la región y en especial a la geológica. Esta última es pródiga en eventos que produjeron montañas, océanos, cavernas, barrancas y otros accidentes geográficos que muestran la complejidad de la región y testifican la existencia de formas de vida que la habitaron durante el pasado remoto mediante el registro fósil.

Research paper thumbnail of ¿Sabías que hay paleontólogos en Hidalgo?

Herreriana Revista de Divulgación de la Ciencia

Research paper thumbnail of Porqué proteger la diversidad geológica: Parte IV

Revista Correo del Maestro

Research paper thumbnail of Porqué proteger la diversidad geológica: Parte III

Revista Correo del Maestro

Research paper thumbnail of THE RECORD OF CAMELIDS (ARTIODACTYLA, CAMELIDAE) FROM THE VALSEQUILLO BASIN, LATE PLEISTOCENE OF PUEBLA STATE, CENTRAL MEXICO: TAXONOMY, DIET, AND GEOGRAPHIC DISTRIBUTION

– Dental and postcranial fossil material referable to camelids, which has been recovered from Qua... more – Dental and postcranial fossil material referable to camelids, which has been recovered from Quaternary deposits that outcrop in the Valsequillo Basin, Puebla State, central Mexico, is formally described. A comparative study indicates the presence of two species of camelids, including Hemiauchenia macrocephala and Camelops hesternus. The sample referable to H. macrocephala includes maxillary and mandibular fragments, isolated teeth, and several postcranial remains (astragalus, metapodials, and proximal phalanges), which show the following diagnostic features of the species: molariforms covered by a layer of cementum; a mandible increasing in depth from p4 to m3; p4 triangular in outline; long and slender metapodials; and proximal phalanges with a W-shaped suspensory ligament scar. The sample referable to C. hesternus is represented by maxillary and mandibular fragments, isolated teeth, and metapodials, sharing with the species its large size; P4 quadrate in outline; p4 triangular in outline and simply folded; and a mandible that is significantly deeper from p4 to m3. A microwear analysis was performed in order to characterize the diet of studied samples, indicating a browser and mixed feeding behavior in H. macrocephala and C. hesternus respectively. The differences in size and trophic regimes in these species should explained the resource partitioning between them. In the late Pleistocene these camelids were common in Mexican sites between the 19°-25° N, and the record from the Valsequillo Basin is one of the few sites where both species have been reported.

Research paper thumbnail of Canid Coprolites from the Late Pleistocene of Hidalgo, Central Mexico: Importance for the Carnivore Record of North America

We present the first reported occurrence of canid coprolites from the late Pleistocene of central... more We present the first reported occurrence of canid coprolites from the late Pleistocene of central Mexico. The sample consists of five associated coprolites recovered from Quaternary deposits that crop out in southeastern Hidalgo, central Mexico. The material shows several of the typical features of canid feces, including elongated cylindrical shape, uncommon and nondistinct constrictions, and one tapered end. The coprolites are similar in size to feces of North American foxes, such as Vulpes macrotis, V. lagopus, V. vulpes, and Urocyon cinereoargenteus; likewise, their size might be comparable to those of the Pleistocene canid Canis cedazoensis. The content of the studied coprolites consists of numerous teeth and bone fragments referable to the pocket gophers Pappogeomys or Cratogeomys. The coprolite content is related to a mostly carnivorous diet comparable to that of C. cedazoensis, wolves (Canis lupus, C. rufus, and C. dirus), and some foxes (V. macrotis and V. velox). As a result, it is proposed that the potential trace maker of the coprolites could be a form similar to a carnivorous fox or a small dog. These trace fossils represent the first indirect evidence of canids in the late Pleistocene of Hidalgo and provide additional information regarding the geographic distribution of the Canidae in temperate areas of North America that now are part of central Mexico during the second half of the Pleistocene.

Research paper thumbnail of First occurrence of Panthera atrox (Felidae, Pantherinae) in the Mexican state of Hidalgo and a review of the record of felids from the Pleistocene of Mexico

Panthera atrox was a common large-sized cat in North America during the late Pleistocene. An isol... more Panthera atrox was a common large-sized cat in North America during the late Pleistocene. An isolated lower canine and a fifth metacarpal bone referable to this species were recovered from fluvial Quaternary deposits that outcrop in southeastern Hidalgo, central Mexico. Associated fossil material belonging to Bison indicates a Rancholabrean North American Land Mammal Age; the age assignment is corroborated by the presence of P. atrox. A comparative study with selected specimens of Panthera and Smilodon indicates that the Hidalgoan sample shares the following diagnostic features with P. atrox: a large, robust, and non-strongly curved lower canine; a large and relatively slender fifth metacarpal with a well-developed projection on the palmar side at the proximal end, narrow articulating surface for the unciform; a narrow notch on the articulating surface for the fourth metacarpal; and a diaphysis that at the middle is oval in cross section. The record supplements the evidence of P. atrox in central Mexico and represents the first reported occurrence of this cat species in the state of Hidalgo. By the same token, the known geographic distribution of P. atrox in the Mexican territory suggests that it was relatively common in temperate areas of central Mexico between 19 and 24 • N at an altitudinal range from 1500 to 2250 m a.s.l. The large size (mean body mass of 300 kg) and hypercarnivorous adaptations of the American lion suggest it was the top predator of the mammalian community recorded at southeastern Hi-dalgo, displacing other members of the carnivore guild at the mesopredator level, such as the dire wolf (Canis dirus), which has been also reported in the area. The high diversity of large herbivores recorded at southeastern Hidalgo, which in turn could represent potential prey of P. atrox, suggests that some areas that now are part of central Mexico were suitable hunting sites for this large-sized cat. A review of the Pleistocene record of Felidae from Mex-ico revealed that it encompasses 87.5 and 73.3 % of generic and specific diversity known for North America,

Research paper thumbnail of Repartición 
de 
recursos 
en 
una 
asociación 
de
 mamíferos 
del 
Pleistoceno
 tardio 
del 
Estado
 de
 Hidalgo

La evaluación del sobrelapamiento de nicho basado en el hábito alimentario de organismos reciente... more La evaluación del sobrelapamiento de nicho basado en el hábito alimentario de organismos recientes, permite conocer la repartición de recursos en una comunidad. En este trabajo se implementó en una asociación de mamíferos pleistocénicos del estado de Hidalgo, usando datos de [δ]13C con los cuales se categorizó el hábito alimentario de los taxones: Hemiauchenia gracilis, Camelops sp., Mammut americanum, Cuvieronius sp., Paramylodon cf. harlani, Odocoileus cf. virginianus, Capromeryx minor, Equus conversidens, Mammuthus sp. y Bison cf. antiquus. Se establecieron categorías dietarias con base en el consumo de plantas C4 por taxón: 1. Pacedor estricto (> 90%); 2. Pacedor variable (75% - 90%); 3. Dieta mixta C4 (60% - 75%); 4. Dieta mixta (40% - 60%); 5. Dieta mixta C3 (25% - 40%); 6. Ramoneador variable (10% - 25%); 7. Ramoneador estricto (< 10%). El sobrelapamiento de nicho se estableció mediante el análisis de Modelos Nulos utilizando el programa EcoSim. Con fines de comparación, se implementó la misma estrategia en una comunidad de mamíferos actual en Kenia y en una asociación fósil del Pleistoceno de Bolivia. Los resultados muestran que la mayoría de los mamíferos de la asociación de Hidalgo tuvieron un comportamiento dietario amplio. Por otra parte, se observa que el consumo de plantas C4 de H. gracilis, M. americanum, O. cf. virginianus y Cuvieronius sp. fue semejante (valor de similitud > 0.9), esto sugiere una mayor competencia por los recursos entre estas especies. La información disponible indica que la coexistencia de los mamíferos de Hidalgo estuvo regulada por su capacidad de consumir plantas C3/C4 en cantidades diferenciales y sólo en algunas formas es probable que la competencia halla sido más intensa, lo cual es congruente con el bajo grado de sobrelapamiento de nicho observado (p = 0.10). Un resultado semejante se obtuvo para la comunidad de mamíferos de Kenia y diferente en la de Bolivia; en esta última la competencia por los recursos fue elevada.

Research paper thumbnail of Dieta y Hábitat De Los Caballos Pleistocénicos De Hidalgo y Tlaxcala Mediante El Análisis De Isótopos Estables Δ13C y Δ18O

Research paper thumbnail of Reconstruyendo ambientes antiguos: análisis de isótopos estables

El análisis de isótopos estables en restos fósiles se ha convertido en una herramienta sumamente ... more El análisis de isótopos estables en restos fósiles se ha convertido en una herramienta sumamente utilizada en la reconstrucción de ambientes que existieron hace miles de años. Se aplica este método para caracterizar el hábito alimentario en organis- mos extintos y su utilidad en la interpretación paleoambiental. La información generada evidencia los cambios que ha manifestado la biósfera en estructura, composición, abundancia y diversidad como resultado de las modificaciones ambientales a lo largo del intervalo considerado de la historia de la Tierra, lo cual a su vez tiene implicaciones en la conservación biológica.

Research paper thumbnail of Feeding Ecology of Astrohippus stockii from the Late Hemphillian of Central Mexico: Stable Carbon Isotopes Analysis and Dental Wear Patterns

BioOne sees sustainable scholarly publishing as an inherently collaborative enterprise connecting... more BioOne sees sustainable scholarly publishing as an inherently collaborative enterprise connecting authors, nonprofit publishers, academic institutions, research libraries, and research funders in the common goal of maximizing access to critical research.

Research paper thumbnail of Mammut americanum from the Pleistocene of Hidalgo Description of mastodons (Mammut americanum) from the late Pleistocene of southeastern Hidalgo, central Mexico

Fossil specimens of American mastodons (Mammut americanum) that have been recovered from fluvial ... more Fossil specimens of American mastodons (Mammut americanum) that have been recovered from fluvial sedimentary deposits of the late Pleistocene of southeastern Hidalgo, central Mexico, are formally described. The sample includes cranial and postcranial remains of an adult male that represents one of the most complete mastodons that have been found in Mexico, as well as a molar belonging to an old individual. The material from Hidalgo shows the following diagnostic features of M. americanum: well-developed tusks that curved upward; upper and lower molars with a simple occlusal pattern; last molars with four to five lophs/ids; a medial sulcus between the lophs/ids; a scapula with a straight caudal border, a short and expanded neck, and a glenoid cavity that is oval in outline; a short and robust humerus with a prominent epicondylar crest; a radius with a wide distal end; and an ulna with a well-developed olecranon process and a deep trochlear notch. The dental size of the mastodon from Hidalgo is comparable to that of mastodons from the Gulf Coastal Plain and the Great Lakes region, whereas the limb dimensions are similar to those of the Watkins Glen Mastodon from the late Pleistocene of New York. In order to characterize the diet and habitat of the mastodons from Hidalgo, a stable carbon and oxygen isotope analysis in tooth enamel apatite was performed. The results indicate that studied specimens were mainly C3 browsers (mean δ 13 C isotope value of-10.06 ‰) that thrived in closed habitats covered by high vegetation, such as trees (mean δ 18 O isotope value of-4.31 ‰). This information suggests the presence of closed habitats in the southeastern region of Hidalgo, during the second half of the Pleistocene. Resumen Se describen formalmente ejemplares de mastodontes Americanos (Mammut americanum) recuperados de depósitos sedimentarios fluviales del Pleistoceno tardío del sureste de Hidalgo, centro de México. La muestra incluye elementos craneales y postcraneales pertenecientes a un macho adulto, el cual representa uno de los mastodontes más completos encontrados en México; así como un molar aislado perteneciente a un individuo viejo. El material de Hidalgo muestra las siguientes características diagnósticas de M. americanum: defensas bien desarrolladas que se curvan hacia arriba; molares superiores e inferiores con un patrón oclusal simple; últimos molares con cuatro a cinco lofos/idos; un surco medial entre los lofos/idos; escápula con un borde caudal recto, cuello corto y expandido, así como con una cavidad glenoidea de forma ovalada; húmero corto y robusto con una cresta epicondilar prominente; radio expandido en su extremo distal; y ulna con un proceso olecraneal bien desarrollado que sobresale de la diáfisis, así como con un surco troclear profundo. El tamaño de los elementos dentales del mastodonte de Hidalgo es comparable con el de mastodontes de la Planicie Costera del Golfo y la región de los Grandes Lagos, mientras que las dimensiones de los huesos de las extremidades son similares con las del Mastodonte Watkins Glen del Pleistoceno tardío de Nueva York. Por otra parte, se realizó un análisis de isótopos estables de carbono y oxígeno en esmalte dental para caracterizar la dieta y el hábitat de los mastodontes de Hidalgo. Los resultados de este análisis indican que los ejemplares estudiados fueron ramoneadores de plantas C3 (valor promedio de δ 13 C de-10.06 ‰) y que

Research paper thumbnail of Dietary analysis of Late Cenozoic Mexican equids from three different geographic/geologic settings using stable carbon isotopes: Coincidences, differences and paleobiologic significance

The development of Vertebrate Paleontology in Mexico is uneven, so that there is a strong bias in... more The development of Vertebrate Paleontology in Mexico is uneven, so that there is a strong bias in favor of Neogene/Quaternary mammals largely collected in the Trans-Mexican Volcanic Belt (TMVB hereafter) and Central Plateau (CeP hereafter) Morphotectonic Provinces [MP hereafter]; however, the time is ripe for pursuing research in other than taxonomic areas. Here we investigate C 3 /C 4 plant consumption in the equid lineage in three such provinces, which provide different geographic/geologic and paleoecologic scenarios during the Barstovian, Hemphillian and Rancholabrean times. Our results show that the Barstovian equids from Oaxaca, Sierra Madre del Sur MP Cormohipparion aff. C. quinni, Merychippus cf. M. sejunctus and Pliohippus sp. largely fed on C 3 plants, which were the chief food stuff of horses in Mexico, particularly in the Southeast. On the other hand, the Hemphillian equid from Guanajuato, CeP Astrohippus stocki, was an unbalanced C 3 /C 4 mixed feeders in favor of C 4 plants, a fact that indicates a profound plant diversification due to the inception and rapid diversification of C 4 plants that occurred there at this time, as it occurred in temperate North America, resulting in the differential consumption of C 4 plants over that of C 3 plants. Such trend prevailed until the Rancholabrean, as born out by the inferred diet for Equus conversidens and Equus sp. from Hidalgo, TMVB. Clearly then, the coeval diet change observed in Mexico and temperate North America implies a correlative vegetation change resulting in the appearance and rapid diversification of C 4 plants, which largely formed the preferred food stuff of equids since the Hemphillian, although some C 3 plant consumption was maintained till the Rancholabrean. It should be noted that the development of hypsodonty in equids and many artiodactyls, has long been interpreted as the adaptive mammalian response to the new feeding conditions.

Research paper thumbnail of The record of Cenozoic horses in Mexico: current knowledge and palaeobiological implications

Fossil horses in Mexico have been documented for 150 years. At present, there exists an abundant ... more Fossil horses in Mexico have been documented for 150 years. At present, there exists an abundant and diverse record that deserves consideration. In this contribution, we offer an overview of the current knowledge on the fossil hors- es in Mexico. The Mexican record of the family Equidae in- cludes early horses and representatives of the subfamilies Anchitheriinae and Equinae. The diversity of horses in Mexico includes 15 genera and 28 species with ages ranging from early Eocene to late Pleistocene. The record of the sub- family Equinae from the upper Neogene and Quaternary de- posits from central Mexico represents the largest proportion of fossil horse evidence in the country. Of the species observed within the Mexican territory, 75 % were at their southernmost extent in North America. The Mexican record shows that a considerable portion of the evolutionary history of horses occurred in Mexico. Nevertheless, the study of fossil horses in Mexico is ongoing. Therefore, including the Mexican
specimens in studies using biogeographical, evolutionary and ecological approaches will considerably improve our knowledge of horses in southern North America.

Research paper thumbnail of First reported occurrence of Palaeolama mirifica (Camelidae, Lamini) from the Late Pleistocene (Rancholabrean) of Puebla, central Mexico

Palaeolama was a relatively rare camelid in North America during the Pleistocene. Here we report ... more Palaeolama was a relatively rare camelid in North America during the Pleistocene. Here we report the first occurrence of P. mi- rifica in the Late Pleistocene of Puebla, central Mexico. This is the southernmost record of P. mirifica in North America, and fills in a geographic gap with a record of the species in Costa Rica. The fossil-bearing unit is composed of silt, fine sand, and scarce pebbles. This unit is partially correlative with the alluvial sequence of Axamilpa, Puebla, considered to be MIS 2 – 3 in age. Isotopic data and Mesowear III values indicate that P. mirifica from Barranca Xocoa was an intermediate feeder.

Research paper thumbnail of Reconstruyendo ambientes antiguos: análisis de isótopos estables

C I E N C I A e r g o -s u m , ISSN 1405-0269, V o l . 21-3, noviembre 2014-febrero 2 0 15. Unive... more C I E N C I A e r g o -s u m , ISSN 1405-0269, V o l . 21-3, noviembre 2014-febrero 2 0 15. Universidad Autónoma del Estado de México, Toluca, México. Pp. 237-242.

Research paper thumbnail of A roe deer from the Pliocene of Hidalgo, central Mexico

Cuevas, V.M. 2015. A roe deer from the Pliocene of Hidalgo, central Mexico. Acta Palaeontologica ... more Cuevas, V.M. 2015. A roe deer from the Pliocene of Hidalgo, central Mexico. Acta Palaeontologica Polonica 60 (4): 807-813.

Research paper thumbnail of A summary of the Mesozoic vertebrate tracks of Mexico

Dinosaurs and other reptiles from the Mesozoic Mexico

Research paper thumbnail of Taxonomy and notes on the paleobiology of the late Pleistocene (Rancholabrean) antilocaprids (Mammalia, Artiodactyla, Antilocapridae) from the state of Hidalgo, central Mexico

Revista Mexicana de Ciencias Geológicas

A set of cranial and dental material of Antilocapridae was recovered from Quaternary deposits tha... more A set of cranial and dental material of Antilocapridae was recovered from Quaternary deposits that outcrop in southeastern Hidalgo, central Mexico. The fossil bearing unit consists of clay, silt, sand, and scarce conglomeratic lenses in a fluvial environment; the specimens are associated with Bison indicating a Rancholabrean Land Mammal Age. The comparative study of the material with selected specimens of North American antilocaprids, allowed its identification as the small-sized species Capromeryx minor and the medium-sized Stockoceros conklingi. The sample referable to C. minor shows a combination of cranial and dental characters typical of this species, including a large posterior tine that is curved upward and forward, posterior horn core with a deep sulcus on its posterior side that extends from the base to the tip, and well-developed heel on M3. The isotopic analysis of teeth referable to this species from Hidalgo indicates a mixed feeding dietary behavior. A partial skull and associated horn core fragments were assigned to Stockoceros conklingi, considering its larger size than C. minor and shorter than the extant pronghorn Antilocapra americana, as well as for having symmetrical and diverging horn cores, and more outwardly flaring horn cores. The recognition of these antilocaprids in southeastern Hidalgo represents one of the southernmost occurrences within temperate North America. The tiny Capromeryx minor is known in North American localities of lower altitude (0-100 m a.s.l.) compared to those of the medium-sized Stockoceros conklingi . Hence, body size differences between both species and altitude differences between some of their localities suggests minimal direct competition between these antilocaprids.

Research paper thumbnail of Darwin y Wallace: Los niveles a los que ocurre la Selección Natural

Herreriana Revista de Divulgación de la Ciencia (Número Especial Darwin 2009)

La selección natural es una fuerza evolutiva, causa principal de la adaptación biológica en las p... more La selección natural es una fuerza evolutiva, causa principal de la adaptación biológica en las poblaciones. También es responsable del surgimiento de las adaptaciones, entendidas como caracteres fenotípicos que tienen una función específica en los organismos que las poseen .

Research paper thumbnail of Descubriendo el pasado remoto de Hidalgo

Herreriana Revista de Divulgación de la Ciencia

La relativa pequeñez del territorio hidalguense contrasta con su variedad de paisajes y riqueza h... more La relativa pequeñez del territorio hidalguense contrasta con su variedad de paisajes y riqueza histórica; por supuesto nos referimos a la historia natural de la región y en especial a la geológica. Esta última es pródiga en eventos que produjeron montañas, océanos, cavernas, barrancas y otros accidentes geográficos que muestran la complejidad de la región y testifican la existencia de formas de vida que la habitaron durante el pasado remoto mediante el registro fósil.

Research paper thumbnail of ¿Sabías que hay paleontólogos en Hidalgo?

Herreriana Revista de Divulgación de la Ciencia

Research paper thumbnail of Porqué proteger la diversidad geológica: Parte IV

Revista Correo del Maestro

Research paper thumbnail of Porqué proteger la diversidad geológica: Parte III

Revista Correo del Maestro