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A new specimen of Camelops hesternus (Artiodactyla, Camelidae) from Valsequillo, Puebla, Mexico, with comments about their dietary preferences and the population density of the species
Abstract
Camelidae is one of the most diverse and successful artiodactyl families, with a long geological history and wide geographical range in North America. Camelops hesternus was the one of last camelids in North America during the Pleistocene (Rancholabrean) and its remains have been found from Alaska south into Mexico. Here, we describe a new specimen of this species based on a complete mandible from the Late Pleistocene sediments of the Cerro Grande de la Mesa Calderón monogenetic volcano in the Valsequillo Basin, Puebla, central Mexico. A mesowear analysis of the dentition indicates wear in the new specimen to be similar to that of the Klipspringer, Oreotragus oreotragus, indicating a browsing diet. The population density of C. hesternus in the Valsequillo Basin was estimated using a differential non-linear equations mathematical model under three scenarios (stress, optimal, and abundance conditions) a indicating the range in its population density of 0.51-1.8 ind/km2, and this species was not abundant in the region. Despite the low population density C. hesternus has been reported in Mexico from 27 Pleistocene localities, with a geographic range from north (29°40' latitude, Sonora) to south (16°14' latitude, Chiapas) at an altitude range of 0–200 m asl in Baja California Sur to 2,500 m asl in the Trans-Mexican Volcanic Belt.
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Paramylodon harlani was a large ground sloth recorded across North America, from Canada to Mexico. In Mexico, it is known from several late Pleistocene localities, but most of these records just mention the taxon in passing and few specimens have been described or illustrated. In this work, we describe a left tibia from the Valsequillo Basin, Puebla state. Its morphology and measurements allowed us to identify it as Paramylodon harlani, adding a new record for Mexico. In Mexico, P. harlani occurred mainly in the Trans-Mexican Volcanic Belt, central Mexico, with some records in the north and southeastern partof the country. Most localities are located between 1500 to 2000 m.a.s.l. Paleoenvironmental and paleoclimatic inference in some localities of Mexico where P. harlani occurred, showed heterogenous vegetation dominated by grasslands, and agree
with the preferred habitat proposed for this species based on localities in the United States. This indicates that P. harlani could inhabit different environments, from grasslands to more wooded areas, and this adaptation allowed it to extend its range from the north to the southeast of Mexico.
We describe a well-preserved South American Lamini partial skeleton (PIMUZ A/V 4165) from the Ensenadan (~ 1.95–1.77 to 0.4 Mya) of Argentina. The specimen is comprised of a nearly complete skull and mandible with full tooth rows, multiple elements of anterior and posterior limbs, and a scapula. We tested this specimen’s phylogenetic position and hypothesized it to be more closely related to Lama guanicoe and Vicugna vicugna than to Hemiauchenia paradoxa . We formulate a hypothesis for the placement of PIMUZ A/V 4165 within Camelinae in a cladistic analysis based on craniomandibular and dental characters and propose that future systematic studies consider this specimen as representing a new species. For the first time in a morphological phylogeny, we code terminal taxa at the species level for the following genera: Camelops , Aepycamelus, Pleiolama , Procamelus, and Alforjas. Our results indicate a divergence between Lamini and Camelini predating the Barstovian (16 Mya) . Camelops appears as monophyletic within the Camelini. Alforjas taylori falls out as a basal member of Camelinae—neither as a Lamini nor Camelini. Pleiolama is polyphyletic, with Pleiolama vera as a basal Lamini and Pleiolama mckennai in a more nested position within the Lamini. Aepycamelus and Procamelus are respectively polyphyletic and paraphyletic. Together, they are part of a group of North American Lamini from the Miocene epoch.
The foraging ecology and diurnal activity patterns of the klipspringer (Oreotragus oreotragus) were studied in Yetefet Woyenat Forest from September 2017 to August 2018 during the dry and wet seasons. Data were collected by visual observation using focal and scan sampling methods. The result indicated that klipspringers were observed feeding on grasses, herbs, trees, and shrubs, but were primarily browsers during both wet and dry seasons. Carissa edulis was the most consumed plant species in the study area, followed by Rosa abyssinica and Maytenus arbutifolia. Despite moderate ambient temperatures, klipspringers were mostly active during early morning and late afternoon, feeding 45.56% of the daylight hours during the dry season and 43.75% during the wet season. Klipspringers were facing threats due to human activities in the study area. Thus, appropriate conservation measures should be taken to reduce disturbance of their ecology.
Equids are among the most common mammals found in faunal assemblages of Late Pleistocene age in Mexico. Much of what is known about the Equus species is the result of studies conducted in central and northern Mexico; much less is known about species in lower latitudes of Mexico. Here we describe three species that inhabited Oaxaca and Chiapas states. The fossil localities are in northwestern and central Oaxaca, as well as the central part of Chiapas. In Oaxaca, the largest species, Equus mexicanus, and the medium-sized Equus conversidens are represented by mandibles, skulls, diverse isolated teeth and some postcranial bones, while the smallest species, Haringtonhippus francisci is represented by a skull fragment and few isolated teeth. In Chiapas, E. mexicanus is represented by a mandible and several isolated teeth, E. conversidens by several mandibles and diverse isolated teeth, and H. francisci by isolated teeth and two mandibles. AMS radiocarbon and uranium dating of some of the equid localities in Oaxaca and Chiapas indicate that they were at least present since approximately 44,000 Cal BP years, they were common around 30,000 Cal BP years, and were still present at the end of the Pleistocene, around 12,000 years ago. The record of H. francisci from Chiapas is the youngest in North America.
A cluster analysis of extended mesowear data and a discriminant analysis showed that Equus conversidens from Chiapas was obligate grazer, whilst the rest of the equids were variable grazers.
Geographic distribution of localities in southern Mexico indicates that during the Pleistocene the equid species moved across the Transvolcanic Belt-Sierra Madre del Sur temperate biogeographic corridor and the Tamaulipas-Central America Gulf Lowlands tropical corridor.
Dromedary camels have been shown to be the main reservoir for human Middle East respiratory syndrome (MERS) infections. This systematic review aims to compile and analyse all published data on MERS-coronavirus (CoV) in the global camel population to provide an overview of current knowledge on the distribution, spread and risk factors of infections in dromedary camels. We included original research articles containing laboratory evidence of MERS-CoV infections in dromedary camels in the field from 2013 to April 2018. In general, camels only show minor clinical signs of disease after being infected with MERS-CoV. Serological evidence of MERS-CoV in camels has been found in 20 countries, with molecular evidence for virus circulation in 13 countries. The seroprevalence of MERS-CoV antibodies increases with age in camels, while the prevalence of viral shedding as determined by MERS-CoV RNA detection in nasal swabs decreases. In several studies, camels that were sampled at animal markets or quarantine facilities were seropositive more often than camels at farms as well as imported camels vs. locally bred camels. Some studies show a relatively higher seroprevalence and viral detection during the cooler winter months. Knowledge of the animal reservoir of MERS-CoV is essential to develop intervention and control measures to prevent human infections.
Se describen los restos óseos de un camélido procedentes del arroyo La Muela, Baja California Sur, México. Con base en los datos merísticos y a la fórmula dental aquí descrita, el ejemplar fue asignado a Camelops hesternus, especie ampliamente distribuida en Norteamérica durante el Pleistoceno. Además, las comparaciones realizadas con el espécimen descrito por Webb (1965) en La Brea Tar Pits (California) del pozo de alquitrán no muestran diferencias morfológicas significativas, sugiriendo una comunidad faunística alguna vez continua en Norteamérica, extendida hasta el sur de la península de Baja California.
During the past century, fossils of Pleistocene camels have been occasionally reported from unglaciated regions of Alaska and Yukon (collectively known as eastern Beringia), yet detailed descriptions of these materials are limited or lacking altogether. The detailed osteological treatment presented here establishes that these fossils are virtually indistinguishable from the species Camelops hesternus, a common member of Blancan to Rancholabrean faunas and known best from temperate regions of western North America. Metrically, high-latitude members of C. hesternus seem to have been smaller bodied than representatives from more southerly parts of the species range, a finding that is consistent with body-mass differences among populations of other large mammals whose ranges extended into the far north. The presence of C. hesternus in Alaska and Yukon was likely episodic, limited to relatively warm intervals such as the Last Interglaciation (Sangamonian).
Se describen los fósiles de mamíferos pleistocénicos procedentes de la zona de San Mateo Huexoyucán, Tlaxca- la, México, alojados en la Colección Paleontológica de la Benemérita Uni- versidad Autónoma de Puebla. Se cuales seis son nuevos registros para el área de estudio (Bison antiquus, cf. Bison occidentalis, Camelops hesternus, Equus mexicanus, Eremotherium laurillardi cf. ). También se reportan formalmente tres especies que fueron mencionadas en traba- jos previos (Cuvieronius hyodon, Equus conversidens y Mammuthus sp.). La pre- sencia de Bison permite asignar una Edad Mamífero Rancholabreana (Pleistoceno tardío) a la asociación faunística. En concordancia con esto, los fósiles proceden de una secuencia de 51798 47650 años A.P.
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 degrees-25 degrees N, and the record from the Valsequillo Basin is one of the few sites where both species have been reported.
Fossil vertebrates (fishes, amphibians, reptiles, birds and, mostly, mammals) of Plio-Pleistocene age are known from 23 localities/collecting areas in the Mexican state of Jalisco. Almost all of the localities are in alluvial, fluvial or lacustrine strata deposited in the three extensional basins of the Jalisco triple junction, the Tepic-Zacoalco, Colima and Chapala rifts. The majority of the localities (12 of 23) are records of proboscideans, mostly of late Pleistocene Mammuthus (Acatlán de Juarez, Cocula, Ejutla, El Tule, Guadalajara, Palo Dulce [Atotonilco el Alto], Río de Juchipila, San Martin Hidalgo [El Tepehuaje], Santa Catarina, Tamazula, Tapalpa and Tecuitatlán). One site is a fossil fish record (Barranca de Santa Rosa), whereas another (San Gabriel) is a record of the giant ground sloth Eremotherium laurillardi. Two localities yield low diversity Hemphillian mammal assemblages (Los Corrales, Teocaltiche), and two sites yield moderately diverse but largely undocumented late Pleistocene (Rancholabrean) mammal assemblages (Ameca, Atotonilco El Bajo), whereas a third site (San Juan de los Lagos) yields fossil cat (Felipeda) and bird (Avipeda) footprints. Only three areas yield diverse fossil mammal assemblages and a stratigraphic succession of fossils that represent more than one land-mammal " age: " Lago de Chapala, Tecolotlán (including nearby Juchitlán and Colotlán) and Zacoalco. The Chapala succession includes Blancan, Irvingtonian? and Rancholabrean mammal assemblages, whereas in the Tecolotlán area Hemphillian and Blancan assemblages are present; the Hemphillian assemblage is associated with an ~4.9 Ma radioisotopic age. At Zacoalco, Irvingtonian? and Rancholabrean mammal assemblages are present. There is no demonstrable human association with Pleistocene mammals in Jalisco. Much remains to be published on the Plio-Pleistocene vertebrate fossils of Jalisco, particularly with regard to careful documentation of the fossils and their stratigraphic context. However, the assemblages are characteristic of southern North American mammal assemblages both prior to and after the " Great American biotic interchange. " INTRODUCTION
En este capitulo se da una panorámica del desarrollo histórico de la paleomastozoología en Puebla, se presenta el registro de mamíferos del estado, incluyendo las localidades portadoras de huellas y se comenta sobre las perspectivas del registro poblano.
Recent advances in paleogenomic technologies have enabled an increasingly detailed understanding of the evolutionary relationships of now-extinct mammalian taxa. However, a number of enigmatic Quaternary species have never been characterized with molecular data, often because available fossils are rare or are found in environments that are not optimal for DNA preservation. Here, we analyze paleogenomic data extracted from bones attributed to the late Pleistocene western camel, Camelops cf. hesternus, a species that was distributed across central and western North America until its extinction ~13,000 years ago. Despite a modal sequence length of only ~35 base pairs (bp), we reconstructed high-coverage complete mitochondrial genomes and low-coverage partial nuclear genomes for each specimen. We find that Camelops is sister to African and Asian bactrian and dromedary camels, to the exclusion of South American camelids (llamas, guanacos, alpacas, and vicuñas). These results contradict previous morphology-based phylogenetic models for Camelops, which suggest instead a closer relationship between Camelops and the South American camelids. The molecular data imply a Late Miocene divergence of the Camelops clade from lineages that separately gave rise to the extant camels of Eurasia. Our results demonstrate the increasing capacity of modern paleogenomic methods to resolve evolutionary relationships among distantly related lineages.
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Desde el año 2004, personal del Museo de Paleontología "Eliseo Palacios Aguilera", a través del proyecto "Prospección y resguardo del patrimonio paleontológico de Chiapas", ha realizado prospecciones sistemáticas en sedimentos del Pleistoceno tardío que afloran en varios municipios de la región central de Chiapas, donde se han rescatado restos de megamamíferos, de los cuales han sido reportados formal e informalmente los taxones Eremotherium laurillardi, Glyptotherium floridanum, Panthera atrox, Mammuthus columbi, Cuvieronius hyodon, Equus conversidens, Neochoerus aesopi, Bison sp. y Odocoileus virginianus. En los últimos años, los esfuerzos se han centrado en cinco localidades, Los Mangos y Gliptodonte en el municipio de Villaflores, La Simpatía y La Tejería en el municipio de Villa Corzo y El Bajión en el municipio de Suchiapa. De estas localidades sólo La Simpatía ha podido ser fechada con radiocarbono, asignando una edad de 12,600 ±60 años, mientras que el resto de las localidades han sido referidas al NALMA Rancholabreano con base en la asociación faunística. Se han rescatado nuevos restos de megamamíferos, entre los cuales se han identificado taxones que no habían sido previamente reportados, tal es el caso de Camelops cf. C. hesternus, Paramylodon harlani, Equus mexicanus y Smilodon fatalis. Dichos hallazgos documentan los registros más sureños para México, además de contribuir al entendimiento de la distribución de estos taxones en América del Norte. Por otro lado, estudios basados en polen y análisis de mesodesgaste en dientes de E. conversidens, apuntan que durante el final del Pleistoceno, en la región central de Chiapas, predominaban ambientes abiertos de pastizal y vegetación baja. Los taxones de megamamíferos hasta ahora descubiertos corresponden a los ambientes propuestos, por lo que su presencia aporta datos adicionales para conocer las condiciones ambientales que pudieron predominar en esa época.
Using bioegeochemical markers δ13C and δ18O, we determined the diet and habitat of three extinct mammals: Camelops hesternus, Equus sp. and Mammuthus columbi, found in Laguna de las Cruces (San Luis Potosí, México). The statistical comparisons assayed among them showed that there are not differences in their diet since all of them may be classified as C3/C4 mixed feeders. Camelops hesternus used to have the major consumption of C4 plants, meanwhile Mammuthus columbi and Equus sp. ate more C3plants. Those little differences in their feeding habits should explain their coexistence them at the site, that was a grassland with some trees, during Late Pleistocene.
We aim to reconstruct the climatic and environmental conditions in the Valsequillo Basin during the deposition of the Valsequillo gravels between c. 40,000 and 8000 years ago, when large mega-fauna and potentially humans occupied the basin. Fossil freshwater (Fossaria sp. and Sphaeriidae (Family)) and terrestrial (Polygyra couloni, Holospira sp. and Cerionidae (Family)) snail shells from sections within the Barranca Caulapan were collected for oxygen and carbon stable isotope analysis. Oxygen and carbon isotopes in terrestrial and freshwater snail shells relate to local climatic parameters and environmental conditions prevailing during the lifetime of the snail. Whole shell isotope analysis showed that c. 35,000 years ago climate in the Valsequillo Basin was similar to the present day. Between c. 35,000 and 20,000 BP conditions became increasingly dry, after which conditions became wetter again, although this record is truncated. Intra-shell isotopic analyses show that the amount of precipitation varied seasonally during the late Pleistocene. If people did reach this part of the Americas in the late Pleistocene they would have experienced changing long-term and seasonal climatic conditions and would have had to adapt their life strategies accordingly.
Western camel ( C. hesternus ) fossils are rare from Eastern Beringia, thus there is little available information on their chronology, paleoecology, and biogeography in this region. In August of 2010, a partial proximal phalanx of a western camel was recovered from a sedimentary exposure along the White River, in the formerly glaciated terrain of southwest Yukon, northwest Canada. The fossil specimen was recovered in situ from sediments that are correlated by stratigraphic, tephra and radiocarbon data to the Marine Isotope Stage (MIS) 5 interglacial period (Sangamonian). Associated paleoenvironmental data indicates that this western camel inhabited a shrub tundra ecosystem that did not include spruce trees or boreal forest during a relatively cold interval between MIS 5e and 5a. This is the oldest reliably dated western camel fossil from Eastern Beringia and supports the model of range expansion for this species to the high latitudes of northwest North America during the last interglacial ( sensu lato ).
Fossil camelids (Artiodactyla, Camelidae) record for Mexican Late Pleistocene is constituted by Camelops hesternus, Hemiauchenia macrocephala, Hemiauchenia gracilis, and Palaeolama mirifica. It analysed dental microwear and carbon and oxygen stable isotopes in teeth enamel of C. hesternus, H. macrocephala and H. gracilis from two fossil sites (LC-PT, and LP-SA) in west-central Mexico, gaining knowledge about camelids palaeoecology (diet and habitat). Microwear and δ13C values indicate that C. hesternus from both sites had a browser diet with a preference for C3-C4 plants, while H. macrocephala from LC-PT was browser with a predilection for C3 plants, and H. gracilis from LC-PT had a mixed feeder diet with a preference for C3 plants. The δ18O and the aridity index show that camelids in central Mexico were evaporation-sensitive taxa. The results suggest that LC-PT had a heterogeneous environment composed of open areas and closed zones, temperatures between 13.95°C and 19.9°C and extreme seasonal changes. The environment in LP-SA was dominated by open areas, with small closed vegetation patches, a temperature of 16.29°C, and less seasonal variation. The aridity index indicates relatively drier conditions at LP-SA than at LC-PT. Camelid dietary ecology provides an initial reconstruction of a regional paleoenvironment, with diverse ecosystems present.
The pronghorns Texoceros altidens, Subantilocapra garciae and a new specimen of Hexobelomeryx fricki are described. Fossil material was collected from Zanclean age sediments of the informal Rancho Viejo Beds of the San Miguel de Allende Graben, state of Guanajuato, in central Mexico. Analysis of teeth measurements of the four Texoceros species from North America revealed that they cannot be objectively identified, thus, they were synonymized with Texoceros altidens, which has priority. A mesowear analysis of the San Miguel de Allende teeth specimens showed that their mesowear scores are most similar to mixed-feeder and browser ruminants. A discriminant function analysis classified most of the Pliocene pronghorns from Guanajuato as mixed-feeders. Given the occurrence of Texoceros and Subantilocapra in the Hh3 of central Mexico, it is likely that the early evolution of the Recent pronghorn took place in central Mexico. The identified antilocaprid species from San Miguel de Allende, Guanajuato are the most southern records of Pliocene age in North America. (Free download for some time: https://authors.elsevier.com/a/1doxy_KNqlfF11).
Mathematical models are a helpful tool that can help paleoecology research advance in similar ways as the ones already used in theoretical ecology. In this article, we use a mathematical model based on differential equations to estimate the past Mammuthus columbi population in the Valsequillo Basin, Puebla, Mexico. We calibrated the model based on the biological and etiologic parameters of the African elephant Loxodonta africana. In addition to the mean population, the analysis allows inferring the population dynamics of the M. columbi on the Valsequillo Basin. The model is based on the ecological interactions between M. columbi and its food resource. It was found that the population must have been oscillating before an equilibrium was reached. Several potential scenarios based on on-site food production (grass) are here analyzed. It was found that a good efficiency of the M. columbi to find food can lead to recurrent cycles of abundance and famine. In this situation, the M. columbi populations must have emigrate and then immigrate in periodic circles to avoid starvation
Strontium isotopic ratios from dental enamel of fossil camels, Camelops hesternus (n=5), horses, Equus sp. (n = 5), and mammoths, Mammuthus columbi (4) from Laguna de las Cruces, San Luis Potosí, central Mexico, have been used to study their migration behavior. Four camels, all horses, and one mammoth display ⁸⁷Sr/⁸⁶Sr similar to local plants and soils, thus identified as residents. On the other hand, teeth of one camel and two of mammoths show lower ⁸⁷Sr/⁸⁶Sr ratios while one mammoth has higher strontium isotopic ratios, that indicate that they migrated from other localities. Oxygen isotopes from resident animals are similar, that suggests that those individuals drank water from the same source, whereas δ¹⁸O values of migrants are different, confirming the strontium isotopic data findings. However, as yet, it is not possible to determine where the migrants came from because their strontium ratios are different from the plants and soils⁸⁷Sr/⁸⁶Sr values from other Potosian and Zacatecan localities with which they were compared.
The Rancho La Brea locality is world famous for asphaltic deposits that trapped and preserved late Pleistocene megafauna over the last 50,000 years. This wealth of paleontological data allows for detailed investigation into paleoecological changes through the last glacial maximum into the Holocene. Here, we used dental mesowear analyses to infer dietary behavior in Bison antiquus, Equus occidentalis, and Camelops hesternus from five deposits (“pits”) spanning the latest Pleistocene: Pits 77, 91, 13, 3, and 61/67. Mesowear was compared among pits for each taxon and discriminant function and posterior probability analyses were conducted using a modern dataset to predict dietary categories at Rancho La Brea. Published mesowear scores from late Pleistocene Bison, Equus and Camelops from other localities were included in the discriminant function and posterior probability analyses to assess dietary variability among regions. Mesowear for each taxon did not differ among pits. Posterior probabilities and discriminant function analyses recovered E. occidentalis as a strict grazer with B. antiquus and C. hesternus recovered as mixed feeders. The stability of mesowear scores through the latest Pleistocene suggests average diets of these herbivores did not significantly change at Rancho La Brea. This is in contrast to documented changes in climate and flora proxies of southern California. However, it is unclear whether these proxies are representative of climate and floral changes at Rancho La Brea. Mesowear scores from late Pleistocene populations of Equus, Bison, and Camelops indicate little variability in diet in Equus, modest variability in Bison, and high variability in Camelops. These analyses suggest large ungulates may have been more opportunistic in their feeding strategies and highlights the need for using multiple proxies to clarify dietary behavior of herbivores
Proteomic analyses of ancient remains are increasing in number and offer great potential to recover phylogenetic information on extinct animals beyond the reach of ancient DNA, but limitations in proteomic techniques remain unclear. Here we carry out LC-MS/MS sequence analysis of a ~3.5 million year old giant camel specimen from Nunavut along with the younger Pleistocene remains of the Yukon giant camel (c.f. Paracamelus) and the western camel (Camelops hesternus) for comparison with complete sequences to both extant camels (Bactrian and Dromedary) and the alpaca. Although not complete (~75–80% sequence coverage), no amino acid sequence differences were confidently observed between the giant camels and the extant Dromedary, indicative of a closer relationship than that of the extant Bactrian lineage. However, multiple amino acid changes were observed for the western camel (Camelops) collagen sequence, placing it as a sister group to these members of the Camelini tribe consistent recent ancient DNA analyses. Although this supports a role for the sequencing of ancient collagen in the understanding of vertebrate evolution, these analyses highlight the limitations in phylogenetic reconstructions based on partial sequence data retrieved from proteomic analyses, particularly, the impact of omitting even only a single peptide on the resulting tree topology. The presence of other non-collagenous proteins, such as biglycan and PEDF, indicates a further resource for phylogenetic information, but none more promising than the degraded camel albumin seemingly observed in the Pliocene specimen. Significance: As proteomics is becoming more frequently used in the study of ancient proteins, an emerging field known as ‘palaeoproteomics’ (or ‘paleoproteomics’), understanding the limitations of the technique is essential. Here, through the study of the oldest undisputed collagen sequences obtained from proteomics, we confirm that some peptides following diagenetic modifications of tryptic sites are no longer matched with standard searches, but can be matched with Error Tolerant searches. We also demonstrate the ability to retrieve phylogenetic information consistent with that of ancient DNA methods, but that with the omission of only one or more key peptides, the inferred evolutionary relationships change. This is a significant finding for the field of palaeoproteomics implying a need for better understanding the particular composition of the partial sequences retrieved from proteomic analyses.
The La Brea Tar Pits are a highly fossiliferous late Pleistocene locality, with over 230 vertebrate species, and the potential to help clarify the ecology of Pleistocene megafauna prior to their extinction. Here, we analyze dental microwear textures, dental mesowear, and stable carbon isotopes to assess the dietary behavior of the three most abundant ungulates at La Brea. We examined Bison antiquus, Camelops hesternus, and Equus occidentalis teeth from pits spanning the latest Pleistocene, focusing on pit 77 (~ 35 Ka, glacial period), and pits 61/67 (~ 11.5 Ka, interglacial period). Dental microwear attributes demonstrate that B. antiquus and E. occidentalis consumed foods with similar textural properties to those preferred by mixed feeding and browsing bovids, as well as significantly different food textures than the diet of modern bison and horses. Camelops hesternus has attributes most similar to modern browsing bovids and giraffes, revealing that all taxa studied likely consumed at least some woody browse. Complexity values (Asfc) in B. antiquus and E. occidentalis are significantly greater at pit 77 than at pits 61/67 and modern populations, suggesting a dietary decrease in woody vegetation and shrubs from the glacial to interglacial period. Dental mesowear values further indicate that B. antiquus and C. hesternus consumed woody vegetation, whereas E. occidentalis grazed. The different dietary interpretation for E. occidentalis may reflect a discrepancy between its average diet inferred from mesowear and its most recent diet inferred from microwear. Lastly, stable carbon isotopes reveal diets composed mostly of C3 vegetation, with B. antiquus incorporating significantly more C4 vegetation than either of the other dominant herbivores during the accumulation of both assemblages. Collectively, these data suggest that the dietary ecology of the dominant La Brea herbivores was more nuanced than previously thought, shifting coincident with changing climates, and not necessarily predictable from morphology or any one proxy method.
Wild members of Camelidae live in some of the most arid environments, including North Africa, Arabia, the Gobi Desert of China and Mongolia and high elevation environments in the Andes Mountains. A better understanding of the paleoecology of the three most abundant Pleistocene camelids (Camelops, Hemiauchenia, and Palaeolama) may clarify modern adaptations to arid environments. Mammalian tooth enamel δ¹³C values were used to compare diets of co-occurring species in California, Texas, and Florida and δ¹⁸O values were used to investigate climate. Carbon isotope analysis suggests Camelops was likely an opportunistic browser that consumed both C3 and C4 browse/CAM plants, potentially consuming C4 browse (e.g., saltbush). Hemiauchenia had an opportunistic and highly generalized diet, while Palaeolama was a specialized forest browser. Stable oxygen isotopes and aridity index values suggest that Ingleside was warmer than McKittrick Brea, but there are no significant differences in aridity between the two sites. Co-occurrence data from the Paleobiology Database suggest that Palaeolama was restricted to forested environments as it occurred with two browsers, Tapirus and Odocoileus at 90.5% of all sites. Camelops and Hemiauchenia both co-occurred with a broader range of taxa, further suggesting these camelids lived in diverse habitats. The generalized diet of Hemiauchenia, the likely ancestor of modern South American camelids, allowed for the adaptations of extant Lama and Vicugna to survive in the arid environments of the Andes Mountains. Collectively, these data clarify the dietary ecology of extinct camelids and provide insight into the potential importance of generalist diets for increased resilience to changing environments and/or climates.
We review the history of investigations at the Valsequillo archaeological area south of Puebla, Mexico, from the early 1960s to 2010. Evidence from diatoms, (U-Th)/ He measurements, early uranium-series dates, later zircon fission-track dates, mineral weathering, tephra hydration dates, and vertebrate fossils imply that the principal archaeological site, Hueyatlaco, could be older than 250,000 years. Hueyatlaco rests unconformably on Xalnene Tuff (basaltic ash) dated at 1.3 Ma by whole-rock argon-argon analysis. This finding differs greatly from a recent interpretation that the site is 40,000 years old.
Whilst in Paris in the month of September last, I was favoured by the Marchioness of Hastings with information of the discovery of the fossils that form the chief subject of the present communication. Her ladyship wrote,—“My search in a particular part of the Eocene beds of the Isle of Wight, where formerly I found that Lophiodon or Palæotherium bone figured in your ‘British Fossil Mammalia,’ has been eminently successful. I have got two portions of jaw and many other bones. I have sketched them for you. Are they Coryphodon or Anoplotherium?” The pen-and-ink sketches, executed with the skill and accuracy of an accomplished artist, showed the fossils to belong to the Anthracotherioid family of Ungulata, with an evident resemblance to that species in the upper molars of which Cuvier had detected a closer resemblance to the Anoplotherium than the same teeth of the typical genus Anthracotherium present
Camelops is a giant llama from the Pliocene and Pleistocene of western North America. Of the 17 species (most, if not all, from the Irvingtonian and Rancholabrean North American Land Mammal Ages) that have been referred to Camelops, only 6 are currently recognised as valid. This review examines Camelops from the Irvingtonian and Rancholabrean (Middle and Late Pleistocene) and describes for the first time material from the latest Wisconsinan of the Nueces River valley of South Texas. During this interval, there are two valid previously named species: the smaller mainly Irvingtonian Camelops minidokae and the larger, mainly Rancholabrean Camelops hesternus. Camelops hesternus, Camelops sulcatus, Camelops huerfanensis and Camelops traviswhitei are junior synonyms of Camelops hesternus. In addition, there are possibly two additional species: one with short, broad metapodials and one with short, slender metapodials.
A new approach of reconstructing ungulate diets, the mesowear method, was introduced by Fortelius, Solounias (2000). Mesowear is based on facet development on the occlusal surfaces of the teeth. Restricting mesowear investigation on the M2 as has previously been suggested would limit application of the mesowear methodology to large ungulate assemblages. Most of the fossil, subfossil and recent ungulate assemblages that have been assigned to a single taxon have a smaller number of individuals. This results in the demand to extend the mesowear method to further tooth positions in order to obtain stable dietary classifications of fossil taxa. The focus of this paper is to test, if a consistent mesowear classification is obtainable for the remaining positions of the upper cheek tooth dentition (P2, P3, P4, M1 and M3) and for combinations of these tooth positions. For statistical testing, large assemblages of isolated cheek teeth of the Vallesian hipparionine horse Hippotherium primigenium Meyer, 1829 and of two populations of the recent zebra Equus burchelli Gray, 1824 are employed as models. Subsequently, all single cheek tooth positions and all possible combinations of these tooth positions are tested for their consistency in classification of the mesowear variables compared to the M2, the model tooth of Fortelius, Solounias (2000). As the most consistent model for the proposed "extended" mesowear method, the combination of four tooth positions P4, M1, M2, and M3 is identified, which allows to include the largest number of isolated tooth specimens from a given assemblage, and fulfills the demand of being consistent in the dietary mesowear classification with the "original" mesowear method. We propose the "extended" mesowear method to be particularly well suited for the reconstruction of paleodiets in hypsodont equids. © Publications Scientifiques du Muséum national d'Histoire naturelle, Paris.
Hundreds of fossils of middle Pleistocene age mammals have been obtained from the tufa, sands, and gravels of the Tacubaya Formation just east of the City of Aguascalientes, in central Mexico. The fossils are probably of Illinoian age. This is the only large, systematically-collected, local fauna known from the Pleistocene of Mexico. Few remains of small mammals were found, but the Cedazo local fauna includes at least 39 species, three here described as new. The Cedazo local fauna is a unit fauna, representing the kinds of mammals that lived together in one small area during one period of time. The Cedazo local fauna lived on plains or grasslands with brush and trees along watercourses but with no tropical forest element in the environment.
Camelops traviswhitei, from the Cedazo local fauna, Tacubaya Formation, medial Pleistocene age, differs from described species of Camelops in sharply "V"-shaped lakes in both upper and lower cheek teeth, with moderately thick enamel on the labial sides of the lakes but very thin enamel on the lingual sides, and lacking cementum in the lakes. Other species of Camelops have bent-oval lakes, bordered on both lingual and labial sides by thick enamel, and filled with cementum.
Extension of the mesowear method to include the lower cheek teeth of ruminants will dramatically increase sample sizes and thus the statistical power of paleodietary inferences. However, the mesowear method of Fortelius and Solounias, which was designed for application to the upper molars, does not effectively separate ruminant species by diet when applied to the lower teeth. Upper and lower mesowear scores have sometimes been compared among non-analogous cusps (i.e. the buccal cusps of the maxillary teeth, which experience incursion and the buccal cusps of the mandibular teeth, which experience excursion during the chewing stroke). We therefore compare mesowear scores between the buccal cusps of maxillary cheek teeth and the lingual cusps of mandibular cheek for a large sample of ruminants because both cusps experience incursion during the chewing stroke. Using the original mesowear scoring method, we find dietary signal in both the maxillary and mandibular cheek teeth and a high correlation between them using both non-phylogenetic and phylogenetic comparative methods. Noting unique patterns of mesowear among the mandibular teeth, we also propose a new scoring method with additional wear categories that improves dietary inference when applied to the lower teeth and is highly repeatable. We also find that mandibular mesowear scores are consistently lower than for their maxillary counterparts. Although differential wear among the upper and lower teeth is much less apparent when applying our new scoring method, wear differences might relate to anisodonty (i.e. mandibular cheek teeth are narrower). Overall, we recommend our new scoring method for application to the lingual cusps of the lower second molars of fossil ruminants.
Presented here is a cladistic analysis of the South American and some North American Camelidae. This analysis shows that Camelini and Lamini are monophyletic groups, as are the genera Palaeolama and Vicugna, while Hemiauchenia and Lama are paraphyletic. Some aspects of the migration and distribution of South American camelids are also discussed, confirming in part the propositions of other authors. According to the cladistic analysis and previous propositions, it is possible to infer that two Camelidae migration events occurred in America. In the first one, Hemiauchenia arrived in South America and, this was related to the speciation processes that originated Lama and Vicugna. In the second event, Palaeolama migrated from North America to the northern portion of South America. It is evident that there is a need for larger studies about fossil Camelidae, mainly regarding older ages and from the South American austral region. This is important to better undertand the geographic and temporal distribution of Camelidae and, thus, the biogeographic aspects after the Great American Biotic Interchange.
On a review of the various facts and considerations discussed in the preceding pages, it seems clear that the Mammalian fauna of the Fluvio-marine Crag is of a Pliocene age. The undoubted association of M. (Tetraloph.) Arvernensis and of E. (Loxodon) meridionalis in this deposit admits of no other inference. The mixed contents of the Red Crag, including mammalian remains of different strata from the Eocene period upwards, are inferred to have been deposited in the reconstructed strata also within the Pliocene period, since M. (Tetraloph) Arvernensis, which occurs so abundantly in the Red Crag, has not been met with anywhere on the Continent of Europe except in deposits of a Pliocene age. The Red Crag sea appears to have breached a previously established and populated Pliocene land, and to have buried the bones referable to various epochs in the same sea-bottom.