Great American Biotic Interchange Research Articles

Temperature changes affected mammal dispersal during the Great American Biotic Interchange

Temperature changes affected mammal dispersal during the Great American Biotic Interchange

An extinct north American porcupine with a South American tail.

New World porcupines (Erethizontinae) originated in South America and dispersed into North America as part of the Great American Biotic Interchange (GABI) 3-4 million years ago.1 Extant prehensile-tailed porcupines (Coendou) today live in tropical forests of Central and South America.2,3 In contrast, North American porcupines (Erethizon dorsatum) are thought to be ecologically adapted to higher-latitude temperate forests, with a larger body, shorter tail, and diet that includes bark.4,5,6,7 Limited fossils8,9,10,11,12,13 have hindered our understanding of the timing of this ecological differentiation relative to intercontinental dispersal during the GABI and expansion into temperate habitats.14,15,16,17,18 Here, we describe functionally important features of the skeleton of the extinct Erethizon poyeri, the oldest nearly complete porcupine skeleton documented from North America, found in the early Pleistocene of Florida. It differs from extant E.dorsatum in having a long, prehensile tail, grasping foot, and lacking dental specializations for bark gnawing, similar to tropical Coendou. Results from phylogenetic analysis suggest that the more arboreal characteristics found in E.poyeri are ancestral for erethizontines. Only after it expanded into temperate, Nearctic habitats did Erethizon acquire the characteristic features that it is known for today. When combined with molecular estimates of divergence times, results suggest that Erethizon was ecologically similar to a larger species of Coendou when it crossed the Isthmus of Panama by the early Pleistocene. It is likely that the range of this more tropically adapted form was limited to a continuous forested biome that extended from South America through the Gulf Coast.

Reply to the comment on Sanz-Pérez et al., “Paleoenvironment and paleoecology associated with the early phases of the Great American Biotic Interchange based on stable isotope analysis of fossil mammals and new U[sbnd]Pb ages from the Pampas of Argentina” [Palaeogeography, Palaeoclimatology, Palaeoecology 634 (2024), 111917

In the comment on our paper, Prevosti et al. (2024) make a series of criticisms regarding the alleged lack of information provided on the dated samples and their geographic and stratigraphic provenance. In this contribution, we will give a reply to their comments. Our new zircon dating achieves the objective of the original study and provides valuable insights into the paleoecological dynamics of the period. It was out of the scope for our work to undertake a high resolution stratigraphical/sedimentological and dating analysis of each of the selected outcrops/sites.

Comment on “Paleoenvironment and paleoecology associated with the early phases of the Great American Biotic Interchange based on stable isotope analysis of fossil mammals and new U[sbnd]Pb ages from the Pampas of Argentina” by Sanz-Pérez et al. [Palaeogeography, Palaeoclimatology, Palaeoecology, 634 (2024), 111917

Sanz-Pérez et al. (2024) recently, based on detrital zircon, presented new maximum depositional ages for several sites of the Neogene of central Argentina to constraint the age of the faunas studied with stable isotopes. Unfortunately, the precise provenance of the dated samples is not clear. In this comment, we discuss the absence of key basic information to replicate their (geochronological) study, or even to evaluate their inferences and conclusions. Without more information about the precise geographic provenance of the dated detrital zircons, and their stratigraphic position in the geological profile/schema of each locality the interpretation of the authors is not supported by the presented information.

Extinction debt and functional traits mediate community saturation over large spatiotemporal scales.

Determining if ecological communities are saturated (have a limit to the number of species they can support) has important implications for understanding community assembly, species invasions, and climate change. However, previous studies have generally been limited to short time frames that overlook extinction debt and have not explicitly considered how functional trait diversity may mediate patterns of community saturation. Here, we combine data from biodiversity surveys with functional and phylogenetic data to explore if the colonisation events after the Great American Biotic Interchange (closure of the Panamanian Isthmus) resulted in increases in species richness of communities of the snake family Dipsadidae. We determined the number and the direction of dispersal events between Central and South America by estimating ancestral areas based on a Bayesian time-calibrated phylogenetic analysis. We then evaluated whether variation in community saturation was mediated by the functional similarity of six traits for the resident and colonizing snakes and/or local environmental conditions. We found that colonised communities did not support more species than those that were not colonised. Moreover, we did not find an association between the functional diversity across sites and whether they were colonised by members from the lineages dispersing across the Isthmus or not. Instead, variation in species richness was predicted best by covariates such as time since colonisation and local environment. Taken together, our results suggest that snake communities of the Dipsadidae across the neotropics are saturated. Moreover, our research highlights two important factors to consider in studies of community saturation: extinction debt and the functional differences and similarities in species' ecological roles.

The roles of niche divergence, dispersal, and geology on the diversification of Neotropical true frogs from the Rana palmipes species group (Amphibia, Anura, Ranidae) during the Great American Biotic Interchange

The roles of niche divergence, dispersal, and geology on the diversification of Neotropical true frogs from the Rana palmipes species group (Amphibia, Anura, Ranidae) during the Great American Biotic Interchange

The Late Miocene mammals from the Humahuaca Basin (northwestern Argentina) provide new evidence on the initial stages of the Great American Biotic Interchange

AbstractWe describe new Late Miocene mammalian specimens from the Maimará Formation (Late Miocene to Early Pliocene) exposed at Humahuaca Basin (23°–24°S), northwestern Argentina (NWA), and analyse their taxonomy and relevance for our understanding of the initial stages of the Great American Biotic Interchange (GABI). The stratigraphical and geochronological control of the studied specimens indicates a time window of c. 6.6–5.8 Ma. These data are crucial for establishing the oldest records of the Holarctic immigrants of the GABI. The first record of cricetid rodents from the Maimará Formation is reported. Moreover, with an age of c. 6 Ma it is the first appearance datum (FAD) of these rodents in South America. The age of the procyonid Cyonasua recorded in this unit is estimated between c. 6.6 and c. 6.4 Ma. The record of procyonids and cricetids in the same continuous sedimentary sequence suggests that the time interval between the dispersion of both groups into the continent during GABI was c. 1 myr. Of the autochthonous mammals from the Maimará Formation, the first records of litopterns, chlamyphorid and mylodontine xenarthrans, and caviomorph rodents (including new species Pithanotomys? solisae and Palaeocavia humahuaquense) are described. FADs of immigrant and autochthonous mammals in NWA suggest a major faunal turnover during GABI at the Messinian, probably linked to global climatic changes and the tectonic activity that affected the Humahuaca Basin at that time. Hypsodonty, a dominant feature among Maimaran mammals, may be related to a landscape strongly influenced by the Andean uplift.

Brasiliochoerus stenocephalus (Lund in Reinhardt, 1880), a large extinct peccary in late Pleistocene beds of Uruguay: Comparative, isotopic and paleoecological studies

Tayassuids entered South America, forming part of the Great American Biotic Interchange, and have had success in South America since the Pliocene, evolving into six genera, and several species have been described. The extinct peccary Brasiliochoerus stenocephalus in late Pleistocene beds of northern Uruguay (the Sopas Formation) is substantiated based on an almost complete and well-preserved skull. A set of associated diagnostic features supports a confident assignment of the material to this extinct species. This peccary was present in the last 40 ka in this area. It was unearthed together with Tayassu pecari, which is found in the same beds, indicating the co-occurrence of both taxa. According to a quantitative analysis, B. stenocephalus is characterized by having a skull much larger than those of T. pecari and Dicotyles tajacu and equal to or larger than the largest individuals of Parachoerus wagneri. However, if only dental variables are computed, despite having a large skull, it shares the morphospace with T. pecari, with P. wagneri being the species with the largest teeth. A high consumption of C3 plants is suggested by δ13C results, and the same kind of browser diet could be roughly inferred for B. stenocephalus and T. pecari. Considering δ18O and δ13C together, both specimens seem to have eaten mostly in the canopy frugivore range, including leaves and some floor plants. T. pecari seems to have not significantly varied its feeding behavior, at least between ca. 40 ka and today. The isotopic results support a browser semiopen woodland lifestyle in C3–C4 grassland to open-canopy environments reinforced by accompanying fauna.

An elevational shift facilitated the Mesoamerican diversification of Azure-hooded Jays (Cyanolyca cucullata) during the Great American Biotic Interchange.

The Great American Biotic Interchange (GABI) was a key biogeographic event in the history of the Americas. The rising of the Panamanian land bridge ended the isolation of South America and ushered in a period of dispersal, mass extinction, and new community assemblages, which sparked competition, adaptation, and speciation. Diversification across many bird groups, and the elevational zonation of others, ties back to events triggered by the GABI. But the exact timing of these events is still being revealed, with recent studies suggesting a much earlier time window for faunal exchange, perhaps as early as 20 million years ago (Mya). Using a time-calibrated phylogenetic tree, we show that the jay genus Cyanolyca is emblematic of bird dispersal trends, with an early, pre-land bridge dispersal from Mesoamerica to South America 6.3-7.3 Mya, followed by a back-colonization of C. cucullata to Mesoamerica 2.3-4.8 Mya, likely after the land bridge was complete. As Cyanolyca species came into contact in Mesoamerica, they avoided competition due to a prior shift to lower elevation in the ancestor of C. cucullata. This shift allowed C. cucullata to integrate itself into the Mesoamerican highland avifauna, which our time-calibrated phylogeny suggests was already populated by higher-elevation, congeneric dwarf-jays (C. argentigula, C. pumilo, C. mirabilis, and C. nanus). The outcome of these events and fortuitous elevational zonation was that C. cucullata could continue colonizing new highland areas farther north during the Pleistocene. Resultingly, four C. cucullata lineages became isolated in allopatric, highland regions from Panama to Mexico, diverging in genetics, morphology, plumage, and vocalizations. At least two of these lineages are best described as species (C. mitrata and C. cucullata). Continued study will further document the influence of the GABI and help clarify how dispersal and vicariance shaped modern-day species assemblages in the Americas.

Nearctic Pleistocene ungulates from the Pampean region (Argentina) in the historical collections of Santiago Roth in Switzerland: an overview

Nearctic ungulates such as artiodactyls, perissodactyls, and proboscideans arrived in South America during the Great American Biotic Interchange. Among them are camelids, cervids, tayassuids, equids, tapirids and gomphotherids. A historical collection of Nearctic ungulates from Pleistocene deposits of the Pampean region in Argentina is here studied and described. The collection consists of specimens collected by Santiago Roth in the nineteenth century and brought to Europe, where they are housed in the paleontological collections of the University of Zurich and the Natural History Museum of Geneva. Among the taxa reported here are Notiomastodon platensis,Lama guanicoe, Hemiauchenia paradoxa, Tayassu pecari, Morenelaphus sp., Hippidion cf. H. principale, Equus cf. E. neogeus, and other indeterminate gomphotherids, camelids, tayassuids, cervids, and equids. The exact stratigraphic position of these fossils collected more than 130 years ago is in many cases uncertain. The historical collection is still relevant for taxonomic studies and for offering new insights into palaeobiogeography and palaeobiology of mammalian fauna of the region during the Pleistocene.

Glyptotherium cylindricum (Cingulata, Glyptodontidae) from the Late Pleistocene of Guatemala: the most complete record of Glyptodontinae from Central America

Glyptodontinae stand out among the lineages of Glyptodontidae in having the greatest latitudinal distribution, including participation in the Great American Biotic Interchange, with significant speciation in new migration areas. The oldest records of Glyptodontinae occur in northern South America with Boreostemma from the middle Miocene–Pliocene. A later radiation incorporated the austral representatives ‘Glyptodontidium tuberifer’, ‘Paraglyptodon’ spp., Glyptodon munizi, Glyptodon reticulatus and Glyptodon jatunkhirkhi in the late Miocene–Late Pleistocene of southern South America, and the septentrional representatives Glyptotherium texanum and Glyptotherium cylindricum in the Pliocene–Late Pleistocene of North America, Central America and northeastern South America. Although knowledge of North and South American forms has increased in recent years, records from Central America are still scarce and fragmentary. Here we describe the most complete Central American glyptodontine fossils documented to date, which were recovered from the latest Pleistocene of Guatemala. The remains comprise: (1) an incomplete skull, the right and left hemimandibles, a fragmentary pelvis, cervical and caudal vertebrae, and articulated and isolated osteoderms; (2) a fragmentary pelvis, left hind limb (incomplete autopodium) and seven caudal vertebrae; (3) most of a dorsal carapace; (4) six incomplete caudal armature rings; and (5) a left hemimandible with complete dental series. Comparative assessment indicates that these remains are referrable to G. cylindricum. The presence of this species in northern Central America and northern South America during the latest Pleistocene spans more than 2200 km, suggesting a continuous distribution across this region, at least during the Last Glacial Maximum and the early Younger Dryas. Francisco Cuadrelli [ f.cuadrelli@gmail.com ]*, Juan Escamilla [ juanitoesca@gmail.com ] and Alfredo Zurita [ aezurita74@yahoo.com ], Laboratorio de Evolución de Vertebrados y Ambientes Cenozoicos–Centro de Ecología Aplicada del Litoral (CECOAL–CONICET) y Universidad Nacional del Nordeste, Corrientes, Argentina, 3400; David D. Gillette [daviddgillette@gmail.com ], 24 W. Travertine Trail, Flagstaff, AZ 86005, USA; Lorena S. Dávila [ sylodavila@gmail.com ], Colección de Fósiles, Museo Historia Natural, Universidad de San Carlos de Guatemala, Calle Mariscal Cruz 1–56, Zona 10, Ciudad de Guatemala, Guatemala, 01010.

Phylogenomics reconciles molecular data with the rich fossil record on the origin of living turtles

Although a consensus exists that all living turtles fall within either Pleurodira or Cryptodira clades, estimating when these lineages split is still under debate. Most molecular studies date the split in the Triassic Period, whereas a Jurassic age is unanimous among morphological studies. Each hypothesis implies different paleobiogeographical scenarios to explain early turtle evolution. Here we explored the rich turtle fossil record with the Fossilized Birth-Death (FBD) and the traditional node dating (ND) methods using complete mitochondrial genomes (147 taxa) and a set of nuclear orthologs with over 10 million bp (25 taxa) to date the major splits in Testudines. Our results support an Early Jurassic split (191–182 Ma) for the crown Testudines with great consistency across different dating methods and datasets, with a narrow confidence interval. This result is independently supported by the oldest fossils of Testudines that postdate the Middle Jurassic (174 Ma), which were not used for calibration in this study. This age coincides with the Pangaea fragmentation and the formation of saltwater barriers such as the Atlantic Ocean and the Turgai Strait, supporting that diversification in Testudines was triggered by vicariance. Our ages of the splits in Pleurodira coincide with the geologic events of the Late Jurassic and Early Cretaceous. Conversely, the early Cryptodira radiation remained in Laurasia, and its diversification ensued as all its major lineages expanded their distribution into every continent during the Cenozoic. We provide the first detailed hypothesis of the evolution of Cryptodira in the Southern Hemisphere, in which our time estimates are correlated with each contact between landmasses derived from Gondwana and Laurasia. Although most South American Cryptodira arrived through the Great American Biotic Interchange, our results indicate that the Chelonoidis ancestor probably arrived from Africa through the chain islands of the South Atlantic during the Paleogene. Together, the presence of ancient turtle diversity and the vital role that turtles occupy in marine and terrestrial ecosystems underline South America as a chief area for conservation.

Pliocene Pre-GABI herbivorous mammals from Espinar, Peruvian Andean Plateau

ABSTRACT Pliocene South American mammals prior to the Great American Biotic Interchange comprise the evolutionary pinnacle of a long-lasting process of continental isolation, in which large-scale orogeny and climate change were instrumental. These processes resulted in unique assemblages of extinct groups with peculiar anatomies. However, interpretation of the functional roles that these organisms would have played in the ecosystem is challenging because well-preserved fossils of this time interval in South America are scarce. Here, we describe a new Early Pliocene assemblage of native herbivorous megamammals documented by skeletons in anatomical connection from the Peruvian Andean plateau (city of Yauri in Espinar, Cusco Department). Fossil-bearing deposits pertain to Member C of the El Descanso Formation dated at 4.75 ± 0.5 Ma, when the plateau attained near-modern elevations and a Puna-type plant ecosystem. The mammal assemblage is dominated by xenarthrans, including three ground sloths (cf. Megatheriops rectidens, Simomylodon uccasamamensis, and Proscelidodon sp.) and Andinoglyptodon mollohuancai gen. et sp. nov., the first Pliocene glyptodontine known by a well-preserved cranium and dermal armor. Notoungulates are represented by the toxodontid Posnanskytherium viscachanense. Both selective and bulk feeders are identified, suggesting the existence of diverse plant resources in the Pliocene Puna ecosystem. These native mammals constituted the typical Pliocene herbivorous guild of the central Andean plateau and provide an opportunity to investigate the structure of mammalian communities just before the arrival of Holarctic immigrants.

New well-preserved materials of Glossotherium chapadmalense (Xenarthra, Mylodontidae) from the Pliocene of Argentina shed light on the origin and evolution of the genus

ABSTRACT Fossil remains of extinct mylodontine sloths have been discovered in numerous localities throughout the American supercontinent, but knowledge of them is still mainly centered on the Pleistocene forms rather than their Neogene relatives. In this contribution, previously unpublished cranial and postcranial materials herein ascribed to Glossotherium chapadmalense (Kraglievich), coming from the Pliocene Chapadmalal Formation (Province of Buenos Aires, Argentina), are presented. These remains are described and compared with those of other mylodontine species from South and North America, providing an exhaustive characterization of cranial morphology in G. chapadmalense and some preliminary insights into its postcranial anatomy. The results have revealed a unique combination of differences and similarities of this enigmatic species with the larger-sized representatives of Glossotherium. In addition, these materials allowed shedding light on the long-standing uncertainties regarding its taxonomic status, as this form has been alternately considered to belong to the genera Glossotherium or Glossotheridium over the last century. As a result, the genus Glossotherium was present, at least, at the Early–Late Pliocene transition in the Pampean region of Argentina, and is recorded by the Upper Pleistocene throughout the entire South American continent. The radiation of the Pleistocene species is associated with a consistent body mass increase that was probably a response to the cooling temperatures and higher predation pressure in South America during the Late Pliocene–Early Pleistocene. These phenomena were probably driven by the stable emergence of the Panamanian Isthmus around 3 Ma and the successive faunal turnover pulses of the Great American Biotic Interchange.

The oldest record of the Lamini Tribe and Proboscidea order in the southwestern margin of the Andes Mountain range: Late Pleistocene mammalian footprints at the Pelluco fossil forest sanctuary

Punta Pelluco is a known fossil forest locality near Puerto Montt in the province of Llanquihue, Southern Chile, which preserves exquisite palynological and xylological records of the last glacial period (Late Pleistocene), discoveries that have been made since 1978. The present investigation contributes the first Chilean record of camelid and proboscidean footprints, discovered in 2015 at Punta Pelluco. The ichnospecies identified are Lamaichnum guanicoe (average footprint 10.1 cm length, 9.9 cm width) and the largest Proboscipeda cf. P. australis (average 38 cm length, 38.2 cm width in the first footprint and average 41.8 cm length, 42.2 cm width in the second footprint) found in South America, respectively. These are the oldest Chilean records for Lamini and Proboscidea, dating back to between about 52.300 and 44.300 years ago. Not much is known about the dispersal of camelids and gomphotherids through the Andean Mountains after the Great American Biotic Interchange, but the present record status seems to indicate that the presence was restricted to the Pleistocene, at least 44,000 years ago.

Upper Pleistocene deposits from the Cauca Valley

The rise of the Isthmus of Panama is one of the major biogeographical events of the Cenozoic. It is a massive natural experiment in biological migrations, as lands formerly separated—South America and Central/North America—became connected. There is, however, a difference in timing between the final closure of the Isthmus (4.2-3.5 Ma) and the onset of the massive mammal migrations (i.e., Great American Biotic Interchange, GABI, 2.7 Ma). This time lag has been brought up to suggest that other factors rather than a land connection were major drivers of the GABI. A large biome change from forest to savanna in Central America and Northwestern South America could have provided the conduit for accelerating the biotic interchange between both continents. This hypothesis has been rarely tested as the Plio-Pleistocene fossil record of those regions has not been sufficiently studied. Gheny K. Shuster discovered a brand new Upper Pleistocene fossil deposit in and under the Cauca River (Southwestern Colombia), one of such possible migration corridors. We conducted a field geophysical and sedimentological study to understand the geometry of the fossil-rich deposits, dated them using carbon isotopes (C14), and assessed the type of biome (savanna versus forest) that dominated the region by looking at pollen samples. We found that the conglomerates accumulated in lenticular bodies, perpendicular to the modern course of the Cauca River during the Late Pleistocene in alluvial fan settings. The vegetation corresponds to a tropical dry forest and there is no evidence of extensive savannas. The Cauca River deposits could become a relevant site for the Neotropical Pleistocene.

A new species of small Camelidae from the Late Pleistocene of Brazil

ABSTRACTCamelids have been known in South America since the late Pliocene, where they arrived from North America as part of the Great American Biotic Interchange (GABI). They became extinct in North America by the late Pleistocene, while surviving in the Southern Cone of South America and in high altitudes of the Andean region. Extinct South American camelids are generally included in the genera Palaeolama and Hemiauchenia, members of which are larger than modern species. We describe here a new, small species of the genus Hemiauchenia based on late Pleistocene specimens previously assigned to Lama guanicoe. This specimen lived in northeastern Brazil at 22 345–21 907 cal a bp, and had a diet composed mainly of C3 plants.

Comparative phylogeography among eight Neotropical wild cat species: no single evolutionary pattern

Abstract The felid species of South America are thought to have arrived on the continent during the Great American Biotic Interchange (GABI) in the Pleistocene. However, molecular and palaeontological data do not agree on how this event affected speciation in felids. Here, we determine both the number of colonization events and the period when felines first migrated from North America to South America. In addition, we evaluate whether similar evolutionary events could have affected the eight Neotropical cat species in their levels of genetic diversity, spatial genetic structure and demographic changes. We analysed four concatenated mitochondrial genes of the jaguar, ocelot, margay, tigrina, pampas cat, Andean cat, puma and jaguarundi. The samples were representative of a wide distribution of these species in Central and South America. Our analysis suggests either three or four colonization events from North America to South America over the past 3 Myr, followed by subsequent speciation events and the attainment of high or very high genetic diversity levels for seven of the species. No unique evolutionary process was detected for any of the current Neotropical cat species.

A Revision of the Didelphid Marsupial Genus Marmosa Part 4. Species of the Alstoni Group (Subgenus Micoureus)

In this report, the fourth of a revisionary series on mouse opossums (Marmosa), we treat the members of a monophyletic group of trans-Andean taxa that include M. alstoni (Allen, 1900); M. nicaraguae Thomas, 1905; and M. adleri, a new species. Although cytochrome b sequence divergence values among these species are substantially lower than distances commonly observed among other congeners, members of the Alstoni Group are strikingly unlike one another in morphological traits. We conjecture that rapid phenotypic divergence accompanied the Pleistocene radiation of an ancestral lineage that entered Central America as a late participant in the Great American Biotic Interchange. Additional undescribed species of the Alstoni Group seem likely to exist based on the evidence at hand, and we emphasize the need for renewed collecting in Central America, which has long been neglected by mammalian biodiversity researchers.

Isotopic evidence for mammalian diets and environment in Early Pliocene Yepómera, Mexico

Concurrent expansion of grassland habitat in the Americas and first appearances of immigrant taxa to Mexico via the Great American Biotic Interchange (GABI) during the Late Miocene to Early Pliocene suggest a possible link between the timing of migrations and changes in the environmental conditions. However, the causes and environmental context of GABI migrations are not well understood. This study examined the stable isotope compositions of tooth enamel samples of the Yepómera fauna from western Chihuahua, Mexico, to explore environmental conditions of this region between 4.99 and 5.23 Ma, just after the arrival of C4 plants in North and South America and before the first major migration of GABI. At Yepómera, there was distinct niche partitioning into C3 diets, mixed diets, and C4 diets. Despite expectations, no niche partitioning between equid species (Dinohippus mexicanus, Nannippus aztecus, Astrohippus stockii, and Neohipparion eurystyle) can be determined from carbon isotope ratios. The enamel carbon and oxygen isotope data suggest a relatively dry, open habitat dominated by either savanna or grassland, with a substantial C4 vegetation component and a warmer and somewhat wetter climate than today. These reconstructions are consistent with a rise in C4 biomass before 5.23 Ma and suggest that the conditions needed for growth of C4 vegetation were prevalent in this region of Mexico. Future work along the GABI migration route will lead to a more complete understanding of the ecologic responses to changing climate and faunal interchange events.