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The gomphotheres were a diverse and widespread group of proboscideans occupying Eurasia, North America, and South America throughout the Neogene. Their decline was temporally and spatially heterogeneous, and the gomphotheres ultimately became extinct during the late Pleistocene; however, the genusCuvieroniusis rarely represented in late Pleistocene assemblages in North America. Two alternative hypotheses have been invoked to explain this phenomenon: (1) competitive exclusion by sympatric mammoths and mastodons or (2) ecologic displacement due to an environmental transition from closed forests to open grasslands. To test whether competition for resources contributed to the demise of North AmericanCuvieronius, we present herein a large collection of stable isotope and dental microwear data from populations occupying their Pleistocene refugium in the Atlantic Coastal Plain. Results suggest thatCuvieroniusconsumed a wide range of resources with variable textural and photosynthetic properties and was not specialized on either grasses or browse. Further, we document evidence for the consumption of similar foods between contemporaneous gomphotheres, mammoths, and mastodons. The generalist feeding strategy of the gomphotheres likely facilitated their high Miocene abundance and diversity. However, this “jack of all trades and master of none” feeding strategy may have proved challenging following the arrival of mammoths and likely contributed to the extirpation ofCuvieroniusin North America.

In 2008 a rich accumulation of vertebrate bones and teeth was discovered in a small tributary drainage to Big Cypress Creek near the town of Hockley in Harris County, Texas. The fossils were recovered from sandy sediments of fluvial origin, interspersed with contemporaneous spring boil deposits, attributed to the Deweyville Formation and the recovered remains consist entirely of disarticulated and dissociated skeletal elements and teeth. Distinct stratigraphic horizons are limited in extent in the fossiliferous sections along the drainage, and the fossils are generally concentrated in close association with gravel lag deposits. Two radiocarbon dates on wood suggest that the fauna may have accumulated about 24,000 years ago but presence of spring deposits, association with lag deposits, and the aerial extent (approximately 125 m of exposed section along the length of the tributary) could indicate significant time averaging during the Rancholabrean (Bison occurs in the fauna). The unique faunal character of the site is emphasized by a single tooth of Mixotoxodon, a notoungulate mammal, that provides the first evidence of this taxon from the United States. The fauna is dominantly composed of herbivorous megafauna with two proboscideans (Mammuthus and Cuvieronius). Mammut americanum has not yet been found in the fauna. Isotopic analyses of the proboscideans and some of the other megafauna suggest that an open environment with scattered woodland habitat existed in southeastern Texas at the end of the last glacial period.

We present a revision, dating and interpretation of the Late Pleistocene megafauna of Guatemala based on paleontological material located in collections in the country and other fossils housed in the American Museum of Natural History, New York. Assemblages are dominated by proboscideans (Cuvieronius) and xenarthrans (Eremotherium, Glyptotherium), while co-occurring Equus and Mixotoxodon are significantly less frequent, and Holmesina, Palaeolama, Tapirus, Neocherus, Mammuthus and other ground sloth taxa (Paramylodon; Megalonyx) are rare. Contrary to published records the faunal assemblage is dominated by North American faunal elements. The underrepresentation of typical South American fauna therefore suggests a more southernly located biogeographic juncture between the two subcontinents, at least for the Late Pleistocene. The biogeographical barrier was either formed by the high mountain chains, or alternating periods of low and high precipitation that triggered the intermittent expansion of either grass- or woodland, thus leading to an alternating filter for either grazers or browsers. The presence of an oak-dominated forest vegetation with Mixotoxodon, Eremotherium and Cuvieronius supports high precipitation rates during MIS 3 and 2, followed by drought during the Late Pleistocene deglaciation. The expansion of grassland during the Younger Dryas period favored the migration of Mammuthus along the Mesoamerican Corridor, which is otherwise absent in Guatemala. Our data also suggest a survival of Cuvieronius into the early Holocene in the southeastern lowlands of Guatemala along the Motagua river. Our review is important as Guatemala is key to understanding migrations along the Mesoamerican Corridor that acted as a bridge but also as a filter of faunal interchange between North- and South America.

The Gomphotheriidae family belongs to the Proboscidea order. Gomphotheres were elephant-like mammals whose representatives inhabited North America from the Middle Miocene to the late Pleistocene. In this work, a gomphothere remains from Santiago Tepeticpac (Tlaxcala, Mexico) are described. The comparative study with other Proboscidea, mainly from different localities of Mexico and South America, mostly Argentina and Brazil, allowed to identify them as Cuvieronius genus. The microwear signature together with carbon and oxygen stable isotopes showed that this animal was a mixer feeder and inhabited open zones with patches of wooded flora. These analyses also indicated the presence of high abrasiveness components and C4 plants (grasslands) and medium to low wearing elements as well as C3 vegetation (forest) in the site. The strontium isotopic signature implies that this gomphothere lived in the Puebla-Tlaxcala Valley. The paleoenvironmental inferences would show regional conditions., We thank Project 11824 of the National Coordination of Cultural Heritage Conservation-INAH for facilitating the collaboration of Dr. María Teresa Alberdi Alonso during the month of November 2016 in the workshop/laboratory of Conservation of Organic Materials of the CNCPC-INAH. To PAPIIT-UNAM-México (#IN404714, IA#104017 and IA#102719), support for this project to Edith Cienfuegos-Alvarado and Víctor Adrián Pérez Crespo. DGICYT CGL2016-79334-P from Spain granted to Maria Teresa Alberdi contributed to funding this investigation., Coordinación Nacional De Conservación Del Patrimonio Cultural (México), Universidad Autónoma Nacional de México

Based on data from analyses on previously-reported carbon stable isotope data from dental enamel and dentine from tusks reported in the literature, diets were inferred for the gomphothere genera Amebelodon, Cuvieronius, Gomphotherium, Rhynchotherium, Serbelodon, and Stegomastodon (Proboscidea, Gomphotheriidae) that inhabited the Americas during the Cenozoic. Amebelodon, Gomphotherium, and Serbelodon specimens of the Barstovian and Clarendonian faunal stages fed on C plants; while the same Hemphillian genera consumed a mixed C/C diet. Hemphillian Rhynchotherium were mixed-diet feeders while Blancan specimens of the same genus fed on C plants. Stegomastodon from the same Blancan period consumed a mixed C/C diet, similar to Rancholabrean animals, although Lujanian specimens ate C plants. As for the genus Cuvieronius, Irvingtonian, Rancholabrean, and Lujanian specimens consumed a mixed C/C diet. These results suggested that American gomphotheres displayed generalist feeding habits, allowing them to inhabit different environments in extensive areas of the continents, and survive to the end of the Pleistocene., To PAPIIT (IA#104017 and IA#102719), for providing financial support for this project to Víctor Adrian Perez Crespo. Research Project ANPCYT PICT 20151512 and Grant UNICEN, Argentina were awarded to Jose Luis Prado; DGICYT CGL2016-79334-P from Spain granted to Maria Teresa Alberdi contributed to funding this investigation.

The diversity of South American proboscideans during the Quaternary has been a subject of discussion for decades. The presence of Cuvieronius hyodon in South America is unquestioned and unanimous; however, the taxonomy of the known second South American proboscidean is still a controversy. Some authors argue that the South American species traditionally referred to Stegomastodon should instead be referred to a distinc genus, namely Notiomastodon, endemic to South America. Others authors, however, do not accept this attribution and continue to recognize the genus Stegomastodon as present in South America. In this study, we recognize several differences in the mandible, skull, dentition, and postcranial morphology of North American species of Stegomastodon and Notiomastodon, that further support the validity of Notiomastodon as a taxon separate from Stegomastodon. Indeed, a phylogenetic hypothesis of trilophodont bunodont proboscideans supports the separation between Stegomastodon and Notiomastodon, and the diversification of the common ancestor of these proboscideans may have occurred during the middle to late Miocene. No specimen with Stegomastodon diagnostic features is recognized in South America. The Stegomastodon records are restricted to the Pliocene-middle Pleistocene of North America, while Notiomastodon records are found only from the middle Pleistocene-early Holocene of South America. In this way, we recognize that Stegomastodon records are restricted to North America and that only Cuvieronius and Notiomastodon are recorded in South America.

The Gomphotheriidae family included a large number of taxa, and a fossil record with extensive geographic and stratigraphic distribution. In South America, the gomphotheres evolved the dibelodont and brevirostrian characteristics, with brachydont, bunodot and subhypsodont molar teeth. Among palaeontologists it is generally accepted the division of gomphotheres into two different groups: the lowland and Andean gomphotheres. There is scientific consensus to designate the species Cuvieronius hyodon as representative of the Andean-type gomphotheres, and in the last few decades, the genus Stegomastodon including its two species S. platensis and S. waringi was described as a lowland-type gomphothere. Recent studies included the genus Stegomastodon within the genus Notiomastodon, with the species Notiomastodon platensis as endemic for the region. In Chile, the most abundant fossils of megafauna from the late Pleistocene—early Holocene limit are gomphotheres, counting with one of the southernmost fossil records that extend to Castro, on the island of Chiloe. The most common fossil remains are molars that are the base of many scientific studies aiming to synthesize the complex history of these mammals. The investigation of the Pilauco site in south-central Chile has improved our paleoecological knowledge of these mammals, as well as the taphonomic processes that favoured their fossilization in southern South America.

Diet and habitat were estimated, based on stable isotopes, for six species of proboscideans inhabiting the Americas during the Pleistocene. In North America, Mammuthus columbi (Elephantidae) was a mixed C3/C4 herbivore inhabiting open areas, while Mammut americanum (Mammutidae) fed exclusively on C3 plants and preferred closed areas. In contrast, members of the family Gomphotheriidae showed a wide range of food preference and habitats. This is the case of Cuvieronius tropicus, a mixed-diet herbivore living in open areas. In South America, another gomphothere — Cuvieronius hyodon — inhabited open areas and had a C3-plant diet similar to others from some Southern plains such as Stegomastodon platensis. On the other hand, S. waringi from tropical South America lived in open areas and had a C3/C4 mixed diet. The fact that gomphotheres had more flexible diet habits could explain why those animals were able to cross the Panamanian Isthmus, while mammoths and mastodons did not.

Fishermen have recovered four Quaternary proboscidean teeth from the continental shelf in the vicinity of the Pearl Islands, about 50–80 km offshore from the southern coast of Panama. Two upper third molars (M3) and one lower third molar (m3) are similar to comparable teeth of the Pleistocene gomphothere Cuvieronius based on the presence of 4½ to 5½ lophs/lophids that are either horizontal or slightly inclined to long axis of the tooth and rather complicated enamel with single trefoils, incipient double trefoils, and numerous small accessory cusps. Cuvieronius is also known from the Pleistocene El Hatillo and La Trinidaita sites from the Azuero Peninsula in Panama. The teeth of Cuvieronius from the Pearl Islands are referred to C. hyodon following recent taxonomic revisions indicating a single pan-American species of this genus was present in both North America and South America. The oldest records of Cuvieronius are from early Pleistocene (early Irvingtonian) faunas in El Salvador, Florida, and New Mexico. Cuvieronius dispersed to South America in the early Pleistocene during the Great American Biotic Interchange, with the earliest record of C. hyodon on that continent from the early to middle Pleistocene (Ensenadan) Tarija fauna in Bolivia. The two late Pleistocene populations of C. hyodon in the Neotropical region have a disjunct biogeographic distribution, with the population from southern Mexico and Central America separated from the second population in the Andean highlands of Ecuador, Peru, and Bolivia by a distance of about 1000 km. The intervening region comprising the lowland tropics of northern South America was populated by the gomphothere Notiomastodon during the late Pleistocene, although Notiomastodon is also known from Andean localities in Ecuador and Peru. Two of the Cuvieronius teeth from the Pearl Islands were recovered in nets by shrimp fisherman from depths of about 90 m, likely indicating they date to the Last Glacial Maximum between 30 and 15 ka, when sea level was as much as 120 m lower than present and the Gulf of Panama was dry land. These teeth represent the first record of late Pleistocene fossils of terrestrial mammals from the continental shelf in Central America.

A lower mastodont molar was found in Nacaome river, Nicoya, Guanacaste, Costa Rica. It is a Pleis- . tocene specimen of Cuvieronius hyodon .C. hyodon and Haplomastodon waringi, mountain and savanna mastodonts respectively, have been found in the same place. This evidence and the dental morphology suggest that they were seasonaly simpatric species with different alimentary niches. Probably H. waringi fed on savanna or prairie plants (very ligneous with high silíca concentration, e.g,Cyperaceae) whereas C. hyodon consumed sQfter plants (the enamel is less damaged).

In 2002, we assessed all sites known to us that had been suggested to provide evidence for the association of Clovis-era archaeological material with the remains of extinct Pleistocene mammals in North America. We concluded that, of the 76 sites we assessed, 14 provided compelling evidence for human involvement in the death and/or dismemberment of such mammals. Of these sites, 12 involved mammoth (Mammuthus), the remaining two mastodon (Mammut). Here, we update that assessment. We examine Clovis-era, and earlier, sites reported since 2002, as well as sites examined previously but for which additional information has become available. Our assessment leads us to exclude Hebior (Wisconsin) from the list of accepted sites, and to add El Fin del Mundo (Sonora) and Wally's Beach (Alberta). There are now 15 sites on our list, providing what we find to be compelling evidence for human involvement in the death and/or dismemberment of five genera of now-extinct late Pleistocene mammals: Equus, Camelops, Cuvieronius, Mammut, and Mammuthus. As in 2002, however, we note this is a small fraction of the 37 genera that disappeared at the end of the Pleistocene, and for this and other reasons we remain highly skeptical that human overkill was responsible for their extinction.

Despite more than two centuries of study, the South American Gomphotheriidae (SAG) taxonomy, phylogeny and biogeography are still problematic. The current knowledge about SAG is outdated and a revision of the classic concepts is necessary. Here, we analyzed a very large sample of Gomphotheriidae remains from North and South Americas. A taxonomic revision based on well-preserved diagnostic materials allowed the recognition of Notiomastodon platensis and Cuvieronius hyodon to South America, which are distributed from lowland to highland localities in this continent. Nevertheless, SAG remains of 66% of analyzed localities are not significantly diagnostic at specific level. Amahuacatherium peruvium diagnostic features are considered invalid and within the morphological variability range expected for N. platensis . The genus Stegomastodon is recognized as absent from South America and morphologically distinct of SAG taxa. The oldest record of SAG indicates that the arrival of this family in South America probably occurred during the Plio-Pleistocene, after the closure of the Isthmus of Panama.

Studies on South American Gomphotheriidae started around 210 years ago and, 150 years later, the classic study “The mastodonts of Brazil” by Simpson and Paula Couto (1957) attempted to clarify the complex issues related to our understanding of these proboscideans. Here, we update state of knowledge regarding proboscideans in South America subsequent to the publication of Simpson and Paula Couto (1957). The taxonomy of South American proboscideans is now stable and two species are recognized, Notiomastodon platensis and Cuvieronius hyodon. The former had a wide distribution in South America (from lowlands to highlands and from east to west coasts), while the latter was restricted to Ecuador, Peru and Bolivia. Although records of Notiomastodon are abundant and occur in almost overlapping geographic distribution with Cuvieronius, they have never been recorded in the same locality. Here, we evaluated over 500 South American localities with proboscidean remains, although only cranial and dental specimens show recognizable diagnostic features. As both proboscideans in South America had a generalist-opportunist alimentary strategy, a competitive exclusion probably precluded their sympatry. Their origin is most probably related to independent migrations from Central America during the Great American Biotic Interchange. They are not sister-taxa – Cuvieronius hyodon is sister-taxon of Rhynchotherium, and this clade is closer to Notiomastodon platensis than to the other proboscideans, supporting the hypothesis of independent origins. Notiomastodon platensis has a continuous record from the Early Pleistocene to Early Holocene, when it became extinct, probably due to synergy of human impact and climatic changes during the Pleistocene/Holocene transition. In contrast, extinction of Cuvieronius hyodon happened much earlier, and it was not related to the terminal Pleistocene event that lead the extinction of selected megafauna in South America, including Notiomastodon., Facultad de Ciencias Naturales y Museo

What is currently known about Mexico paleontology and specifically the proboscideans has centered in the central and southern states, with much of the north largely unknown. Here we report on Cuvieronius (Gomphotheriidae) and Mammuthus (Elephantidae) recovered from Terapa, a Late Pleistocene site in east-central Sonora. The local fauna reflects a badlands environment along the Rio Moctezuma, 183 km (114 mi) south of the Arizona border. The recovery of Bison places the locality within the Rancholabrean Land Mammal Age. Chronological analyses confirm that impounding basalt and fossiliferous sediments were deposited 43,000 to 40,000 years ago (MIS 3). Cuvieronius and Mammuthus are found throughout the stratigraphic profile. A review of Late Pleistocene collections indicates that Mammuthus, Cuvieronius, and one location of Mammut are known from Sonora. The Late Pleistocene along the Terapa river valley is reconstructed as cooler, with a more equable, less seasonal environment than today. The corridor was wetter, more tropical and included a riparian forest, ponding water, marsh, and savanna grassland. The area west of Terapa in western Sonora had a cooler summer climate, more winter rains and less summer rains. Woodlands and shrub communities occupied the upper bajadas and rocky hills, areas possibly where Mammut ranged more commonly. Valleys contained more grasslands than they do today. The environments and climates of valleys permitted Cynomys, Mammuthus, and Cuvieronius to exist over most of western Sonora where they are extinct today.

The Order Proboscidea in Mexico is composed of the families Elephantidae, Mammutidae, and Gomphotheriidae. The last one includes the genus Cuvieronius. In this paper, we present a skull identified as the first record of Cuvieronius hyodon in Valparaiso, southwestern Zacatecas.

The incisors of proboscideans (tusks and tushes) are one of the most important feature in conservation, ecology and evolutionary history of these mammals. Although the absence of upper incisors is rare in proboscideans (occurring only in deinotheres), the independent losses of lower incisors are recognized for most of its lineages (dibelodont condition). The presence of lower incisors in the Pan-American gomphothere Cuvieronius hyodon was reported a few times in literature, but it was neglected in systematic studies. We analyzed several specimens of Cuvieronius hyodon from the Americas and recognized that immature individuals had lower incisors during very early post-natal developmental stages. Subsequently, these are lost and lower incisors alveoli close during later developmental stages, before maturity. Moreover, for the first time in a formal cladistic analysis of non-amebelodontine trilophodont gomphotheres, Rhynchotherium and Cuvieronius were recovered as sister-taxa. Among several non-ambiguous synapomorphies, the presence of lower incisors diagnoses this clade. We recognize that the presence of lower incisors in Cuvieronius and Rhynchotherium is an unique case of taxic atavism among the Elephantimorpha, since these structures are lost at the origin of the ingroup. The rediscovery of the lower incisors in Cuvieronius hyodon, their ontogenetic interpretation and the inclusion of this feature in a revised phylogenetic analysis of trilophodont gomphotheres brought a better understanding for the evolutionary history of these proboscideans.