Mammalian faunal dynamics of the great American interchange

Paleobiology ◽  
1976 ◽  
Vol 2 (3) ◽  
pp. 220-234 ◽  
Author(s):  
S. David Webb
Keyword(s):  
North America ◽  
South America ◽  
Late Pleistocene ◽  
Turnover Rate ◽  
Marked Decrease ◽  
Important Change ◽  
South American ◽  
The Family ◽  
Family Level ◽  
Land Mammal

The American interchange of land mammals reached its acme during the late Blancan and early Irvingtonian in North America and during the Chapadmalalan and Uquian in South America. It lasted about two million years and included taxa adapted to diverse habitats. It was preceded in the early Hemphillian in North America and the Huayquerian in South America by the interchange of a few heralding genera. The MacArthur-Wilson faunal equilibrium hypothesis correctly predicts a marked increase in originations, number of genera, and turnover rate for the South American fauna during the peak of the interchange. Subsequent further increases were not so predicted but closely resemble patterns also observed in late Pleistocene land mammals of Europe and North America. The continued increase in South American land mammal genera after the interchange had largely ceased resulted principally from autochthonous evolution of northern immigrant stocks. A marked decrease in South American ungulate genera (from thirteen to three) coincided with the appearance of fourteen northern ungulate genera and therefore appears to be a replacement phenomenon. The area/diversity relationship predicts no important change in generic diversity if a maximum of only nine percent of North America is occupied by the interamerican mingled fauna. At the family level, however, diversity is seriously overestimated due to the nomenclatural artifact of increased relative diversity by filtering.

scholarly journals Late Pleistocene echimyid rodents (Rodentia, Hystricognathi) from northern Brazil

2016 ◽  
Vol 88 (2) ◽  
pp. 829-845 ◽  
Author(s):  
THAIS M.F. FERREIRA ◽  
ADRIANA ITATI OLIVARES ◽  
LEONARDO KERBER ◽  
RODRIGO P. DUTRA ◽  
LEONARDO S. AVILLA
Keyword(s):  
South America ◽  
Tropical Forests ◽  
Late Pleistocene ◽  
Fossil Record ◽  
South American ◽  
Squamate Reptiles ◽  
Northern Brazil ◽  
Northern South America ◽  
First Time

ABSTRACT Echimyidae (spiny rats, tree rats and the coypu) is the most diverse family of extant South American hystricognath rodents (caviomorphs). Today, they live in tropical forests (Amazonian, coastal and Andean forests), occasionally in more open xeric habitats in the Cerrado and Caatinga of northern South America, and open areas across the southern portion of the continent (Myocastor). The Quaternary fossil record of this family remains poorly studied. Here, we describe the fossil echimyids found in karst deposits from southern Tocantins, northern Brazil. The analyzed specimens are assigned to Thrichomys sp., Makalata cf. didelphoides and Proechimys sp. This is the first time that a fossil of Makalata is reported. The Pleistocene record of echimyids from this area is represented by fragmentary remains, which hinders their determination at specific levels. The data reported here contributes to the understanding of the ancient diversity of rodents of this region, evidenced until now in other groups, such as the artiodactyls, cingulates, carnivores, marsupials, and squamate reptiles.

A molecular phylogeny of the circum-Antarctic Opiliones family Neopilionidae

2021 ◽  
Author(s):  
Gonzalo Giribet ◽  
Kate Sheridan ◽  
Caitlin M. Baker ◽  
Christina J. Painting ◽  
Gregory I. Holwell ◽  
...  
Keyword(s):  
New Zealand ◽  
South America ◽  
Morphological Study ◽  
18S Rrna ◽  
New Caledonia ◽  
Sister Group ◽  
28S Rrna ◽  
South American ◽  
Australian Species ◽  
The Family

The Opiliones family Neopilionidae is restricted to the terranes of the former temperate Gondwana: South America, Africa, Australia, New Caledonia and New Zealand. Despite decades of morphological study of this unique fauna, it has been difficult reconciling the classic species of the group (some described over a century ago) with recent cladistic morphological work and previous molecular work. Here we attempted to investigate the pattern and timing of diversification of Neopilionidae by sampling across the distribution range of the family and sequencing three markers commonly used in Sanger-based approaches (18S rRNA, 28S rRNA and cytochrome-c oxidase subunit I). We recovered a well-supported and stable clade including Ballarra (an Australian ballarrine) and the Enantiobuninae from South America, Australia, New Caledonia and New Zealand, but excluding Vibone (a ballarrine from South Africa). We further found a division between West and East Gondwana, with the South American Thrasychirus/Thrasychiroides always being sister group to an Australian–Zealandian (i.e. Australia + New Zealand + New Caledonia) clade. Resolution of the Australian–Zealandian taxa was analysis-dependent, but some analyses found Martensopsalis, from New Caledonia, as the sister group to an Australian–New Zealand clade. Likewise, the species from New Zealand formed a clade in some analyses, but Mangatangi often came out as a separate lineage from the remaining species. However, the Australian taxa never constituted a monophyletic group, with Ballarra always segregating from the remaining Australian species, which in turn constituted 1–3 clades, depending on the analysis. Our results identify several generic inconsistencies, including the possibility of Thrasychiroides nested within Thrasychirus, Forsteropsalis being paraphyletic with respect to Pantopsalis, and multiple lineages of Megalopsalis in Australia. In addition, the New Zealand Megalopsalis need generic reassignment: Megalopsalis triascuta will require its own genus and M. turneri is here transferred to Forsteropsalis, as Forsteropsalis turneri (Marples, 1944), comb. nov.

The American Proteaceae

1998 ◽  
Vol 11 (4) ◽  
pp. 287 ◽  
Author(s):  
Ghillean T. Prance ◽  
Vanessa Plana
Keyword(s):  
South America ◽  
Molecular Data ◽  
Central American ◽  
General Distribution ◽  
South American ◽  
Land Bridge ◽  
Eastern Brazil ◽  
The Family ◽  
Single Genus ◽  
Morphological And Molecular Data

The American Proteaceae are outliers from the main centres of diversity of the family in Australia and South Africa. There are about 83 species in eight genera which all belong to the monophyletic subfamily Grevilleoideae. Three genera, Embothrium, Oreocallis and Lomatia, are placed in the tribe Embothrieae (sensu Johnson and Briggs), four Euplassa, Gevuina, Panopsis and Roupala in the Macadamieae and the single genus Orites in the Oriteae. There are five genera endemic to America and three also have species in Australia and New Guinea (Gevuina, Lomatia and Orites). The Proteaceae appear to have arrived in South America via two routes. The larger genera Euplassa, Panopsis and Roupala, which are all endemic to America and have a general distribution in northern South America and south-eastern Brazil, are derived from Gondwanaland before it separated from South America. The remaining genera are distributed either in temperate South America or in the high Andes and appear to have arrived more recently via the Australia–Antarctica–South American connection. Three of these genera have species in both regions. The centres of species diversity of Euplassa, Panopsis and Roupala fall outside hypothesised forest refugia, indicating that they are not true rainforest species but species of seasonal habitats like those achieved at higher altitudes where they are commonly found. Two genera,Panopsis and Roupala, have reached Central America after the central American land bridge was formed six million years ago. The exact relationship to genera on other continents is still unclear and there is a need for a cladistic biogeographic analysis of the group based on both morphological and molecular data.

Chronostratigraphy and “Land-Mammal Ages” in the Cenozoic of southern South America: principles, practices, and the “Uquian” problem

1995 ◽  
Vol 69 (1) ◽  
pp. 135-159 ◽  
Author(s):  
Alberto L. Cione ◽  
Eduardo P. Tonni
Keyword(s):  
South America ◽  
Buenos Aires ◽  
New South ◽  
Lower Boundary ◽  
Buenos Aires Province ◽  
South American ◽  
Southern South America ◽  
Matuyama Chron ◽  
Study Case ◽  
Land Mammal

The concept of “land-mammal age” as developed in South America is examined. The “Uquian Land-mammal age” is used as a study case. “Land-mammal age” parataxonomy is here considered methodologically but not conceptually different from chronostratigraphic taxonomy. “Land-mammal ages” in South America are based on stages. However, we consider that accurate biostratigraphic studies must be done in South America for establishing the biostratigraphy and precise boundary stratotypes of most stages-ages. The Uquia outcrops are here considered inadequate as a stratotype. A new South American continental stage-age is proposed. This stage is based on a biostratigraphic scheme. The stratotypes of the stage and biozones are located in the fossiliferous southeastern Buenos Aires Province marine cliffs. The lower boundary stratotype is proposed. The stage-age is probably correlated with the Gauss Chron and the lower Matuyama Chron. Additionally, some major units of Ameghino are validated and a different timing for the arrival of North American mammals to southern South America is presented.

Models for Pleistocene Extinction

1981 ◽  
Vol 2 (2) ◽  
pp. 85-100 ◽  
Author(s):  
Kit W. Wesler
Keyword(s):  
Computer Simulation ◽  
North America ◽  
South America ◽  
Late Pleistocene ◽  
Environmental Changes ◽  
Alternative Formulation

Arguments for Paleoindian overkill of Late Pleistocene megafauna have traditionally emphasized North America with little more than token reference to other areas. Other scholars reject human causation of Pleistocene extinctions, preferring to see in climatic and environmental changes a sufficient explanation for the losses of these forms. This paper discusses the idea of overkill with reference to a computer simulation by Mosimann and Martin (1975), and offers reasons for preferring an alternative formulation. It is also suggested that the case of South America should be reviewed separately, and that an environmental explanation of Pleistocene extinction may be more suitable there.

Ecogeography and the Great American Interchange

Paleobiology ◽  
1991 ◽  
Vol 17 (3) ◽  
pp. 266-280 ◽  
Author(s):  
S. David Webb
Keyword(s):  
North America ◽  
South America ◽  
North American ◽  
Mammalian Fauna ◽  
The South ◽  
Land Bridge ◽  
Southern Mexico ◽  
The North ◽  
Land Mammal ◽  
The Impact

When the isthmian land bridge triggered the Great American Interchange, a large majority of land-mammal families crossed reciprocally between North and South America at about 2.5 Ma (i.e., Late Pliocene). Initially land-mammal dynamics proceeded as predicted by equilibrium theory, with roughly equal reciprocal mingling on both continents. Also as predicted, the impact of the interchange faded in North America after about 1 m.y. In South America, contrary to such predictions, the interchange became decidedly unbalanced: during the Pleistocene, groups of North American origin continued to diversify at exponential rates. Whereas only about 10% of North American genera are derived from southern immigrants, more than half of the modern mammalian fauna of South America, measured at the generic level, stems from northern immigrants. In addition, extinctions more severely decimated interchange taxa in North America, where six families were lost, than in South America, where only two immigrant families became extinct.This paper presents a two-phase ecogeographic model to explain the asymmetrical results of the land-mammal interchange. During the humid interglacial phase, the tropics were dominated by rain forests, and the principal biotic movement was from Amazonia to Central America and southern Mexico. During the more arid glacial phase, savanna habitats extended broadly right through tropical latitudes. Because the source area in the temperate north was six times as large as that in the south, immigrants from the north outnumbered those from the south. One prediction of this hypothesis is that immigrants from the north generally should reach higher latitudes in South America than the opposing contingent of land-mammal taxa in North America. Another prediction is that successful interchange families from the north should experience much of their phylogenetic diversification in low latitudes of North America before the interchange. Insofar as these predictions can be tested, they appear to be upheld.

scholarly journals Distributional patterns of herbivore megamammals during the Late Pleistocene of South America

2013 ◽  
Vol 85 (2) ◽  
pp. 533-546 ◽  
Author(s):  
VALERIA GALLO ◽  
LEONARDO S. AVILLA ◽  
RODRIGO C.L. PEREIRA ◽  
BRUNO A. ABSOLON
Keyword(s):  
South America ◽  
Late Pleistocene ◽  
Geographic Distribution ◽  
Great Influence ◽  
Arid Environment ◽  
Arid Climate ◽  
South American ◽  
Biogeographic Provinces ◽  
Distributional Patterns ◽  
Track Analysis

The geographic distribution of 27 species of the South American megafauna of herbivore mammals during the Late Pleistocene was analyzed in order to identify their distributional patterns. The distribution of the species was studied using the panbiogeographical method of track analysis. Six generalized tracks (GTs) and two biogeographic nodes were obtained. The GTs did not completely superpose with the areas of open savanna present in Pleistocene, nor with the biotic tracks of some arthropods typical of arid climate, indicating that these animals avoided arid environment. Overall, the GTs coincided with some biogeographic provinces defined on the basis of living taxa, indicating that certain current distributional patterns already existed in Pleistocene. The biogeographic nodes coincided with the borders between the main vegetal formations of the Pleistocene, showing that the type of vegetation had great influence in the distribution of the mammalian megafauna. The node 1 confirmed the existence of contact zones between paleobiogeographic regions near Argentina-Uruguay border. The node 2 connects the Brazilian Intertropical regions.

Geographic Variation in Fluted Projectile Points: A Hemispheric Perspective

1999 ◽  
Vol 64 (2) ◽  
pp. 215-230 ◽  
Author(s):  
Juliet E. Morrow ◽  
Toby A. Morrow
Keyword(s):  
North America ◽  
South America ◽  
Geographic Variation ◽  
Great Plains ◽  
North American ◽  
South American ◽  
Western North America ◽  
Radiocarbon Dates ◽  
Projectile Points ◽  
Fluted Points

This paper examines geographic variation in fluted point morphology across North and South America. Metric data on 449 North American points, 31 Central American points, and 61 South American points were entered into a database. Ratios calculated from these metric attributes are used to quantify aspects of point shape across the two continents. The results of this analysis indicate gradual, progressive changes in fluted point outline shape from the Great Plains of western North America into adjacent parts of North America as well as into Central and South America. The South American “Fishtail” form of fluted point is seen as the culmination of incremental changes in point shape that began well into North America. A geographically gradual decline in fluting frequency also is consistent with the stylistic evolution of the stemmed “Fishtail” points. Although few in number, the available radiocarbon dates do suggest that “Fishtail” fluted points in southern South America are younger than the earliest dates associated with Clovis points in western North America. All of these data converge on the conclusion that South American “Fishtail” points evolved from North American fluted points.

scholarly journals A new Palaeocene crocodylian from southern Argentina sheds light on the early history of caimanines

2018 ◽  
Vol 285 (1885) ◽  
pp. 20180843 ◽  
Author(s):  
Paula Bona ◽  
Martín D. Ezcurra ◽  
Francisco Barrios ◽  
María V. Fernandez Blanco
Keyword(s):  
North America ◽  
South America ◽  
Cladistic Analysis ◽  
South American ◽  
North Central ◽  
Skull Roof ◽  
History Of ◽  
Event Based ◽  
Dispersal Events ◽  
North And South America

Caimanines are crocodylians currently restricted to South and Central America and the oldest members are from lower Palaeocene localities of the Salamanca Formation (Chubut Province, Argentina). We report here a new caimanine from this same unit represented by a skull roof and partial braincase. Its phylogenetic relationships were explored in a cladistic analysis using standard characters and a morphogeometric two-dimensional configuration of the skull roof. The phylogenetic results were used for an event-based supermodel quantitative palaeobiogeographic analysis. The new species is recovered as the most basal member of the South American caimanines, and the Cretaceous North American lineage ‘ Brachychampsa and related forms' as the most basal Caimaninae. The biogeographic results estimated north-central North America as the ancestral area of Caimaninae, showing that the Cretaceous and Palaeocene species of the group were more widespread than thought and became regionally extinct in North America around the Cretaceous–Palaeocene boundary. A dispersal event from north-central North America during the middle Late Cretaceous explains the arrival of the group to South America. The Palaeogene assemblage of Patagonian crocodylians is composed of three lineages of caimanines as a consequence of independent dispersal events that occurred between North and South America and within South America around the Cretaceous–Palaeogene boundary.

scholarly journals Nasal mites (Mesostigmata, Rhinonyssidae) in Sternidae (Aves: Charadriiformes) on the southern Coast of Brazil

2018 ◽  
Vol 27 (1) ◽  
pp. 109-111 ◽  
Author(s):  
Diego Silva da Silva ◽  
Simone Scheer ◽  
Gertrud Muller
Keyword(s):  
South America ◽  
Respiratory System ◽  
First Record ◽  
Neotropical Region ◽  
Mite Species ◽  
South American ◽  
Sterna Hirundo ◽  
Southern Coast ◽  
The Family ◽  
The World

Abstract Six species of birds of the family Sternidae are often found on the southern coast of South America. Sterna trudeaui, S. hirundinacea, Thalasseus maximus, T. acuflavidus and Sternula superciliaris are South American residents and Sterna hirundo, a Nearctic migrant. At least 500 species of nasal mites have been described around the world, and Rhinonyssidae is the most diverse family. These mites are bloodsucking endoparasites that inhabit the respiratory system of birds. This study aimed to report on occurrences of nasal mites in Sternidae on the southern coast of Brazil. Of the 106 birds analyzed, 8.5% (9 birds) were parasitized by nasal mites. This report provides the first record in the Neotropical region for two mite species, Sternostoma boydi and Larinyssus orbicularis parasitizing Thalasseus acuflavidus and Sternula superciliaris. No nasal mites were found in Sterna trudeaui or Thalasseus maximus. One host individual (T. acuflavidus) was parasitized by two species of nasal mites, S. boydi and L. orbicularis.

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