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Thylacosmiliformes
Thylacosmiliformes is an extinct clade of predatory metatherian mammals in the order Sparassodonta, related to the marsupials. Members of this clade are known from the Miocene and Pliocene epochs of South America (Argentina, Colombia, and Uruguay). The most notable thylacosmiliforms, such as ''Thylacosmilus'', comprise the more exclusive family Thylacosmilidae and have prominent saber teeth. The clade was defined in 2025 to include thylacosmilids and their more " primitive" closest relatives such as ''Dimartinia''. Description Members of the Thylacosmiliformes are characterized by several anatomical features of the mandible and teeth. These include the presence of two or fewer lower incisors, a lower canine that is compressed laterally, a small or absent first premolar, and an expanded symphyseal region of the dentary's anterior horizontal ramus. Classification In their 2025 description of ''Dimartinia'', Suarez et al. performed a phylogenetic analysis to determine its po ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dimartinia
''Dimartinia'' (after Vicente Di Martino) is an extinct genus of carnivorous metatherian mammals from the Late Miocene Cerro Azul Formation of Argentina. The genus contains a single species, ''D. pristina'', known from a left mandible and teeth. ''Dimartinia'' is a primitive member of the Thylacosmiliformes, a group also containing the saber toothed thylacosmilids. Discovery and naming The ''Dimartinia'' holotype specimen, MMH-CH 87-7-111, was discovered in sediments of the Cerro Azul Formation ('Arroyo Chasicó' locality) in Buenos Aires Province, Argentina. The specimen consists of a left dentary and its associated teeth (partial canine, first–third premolars, and first–fourth molars). In 2025, Suarez et al. described ''Dimartinia pristina'' as a new genus and species of metatherian mammals based on these fossil remains. The generic name, ''Dimartinia'', honors Vicente Di Martino, the collector of the holotype and founder of the museum where the specimen is acces ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Borhyaenoidea
Sparassodonta (from Greek to tear, rend; and , gen. , ' tooth) is an extinct order of carnivorous metatherian mammals native to South America, related to modern marsupials. They were once considered to be true marsupials, but are now thought to be a separate side branch that split before the last common ancestor of all modern marsupials. A number of these mammalian predators closely resemble placental predators that evolved separately on other continents, and are cited frequently as examples of convergent evolution. They were first described by Florentino Ameghino, from fossils found in the Santa Cruz beds of Patagonia. Sparassodonts were present throughout South America's long period of "splendid isolation" during the Cenozoic; during this time, they shared the niches for large warm-blooded predators with the flightless terror birds. Previously, it was thought that these mammals died out in the face of competition from "more competitive" placental carnivorans during the Pli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sparassodonta
Sparassodonta (from Ancient Greek, Greek ['], to tear, rend; and , gen. [', '], tooth) is an extinct order (biology), order of carnivore, carnivorous metatherian mammals native to South America, related to modern marsupials. They were once considered to be true marsupials, but are now thought to be a separate side branch that split before the last common ancestor of all modern marsupials. A number of these mammalian predators closely resemble placental predators that evolved separately on other continents, and are cited frequently as examples of convergent evolution. They were first described by Florentino Ameghino, from fossils found in the Santa Cruz beds of Patagonia. Sparassodonts were present throughout South America's long period of "splendid isolation" during the Cenozoic; during this time, they shared the niches for large warm-blooded predators with the flightless Phorusrhacidae, terror birds. Previously, it was thought that these mammals died out in the face of competi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Middle Miocene
The Middle Miocene is a sub-epoch of the Miocene epoch (geology), epoch made up of two Stage (stratigraphy), stages: the Langhian and Serravallian stages. The Middle Miocene is preceded by the Early Miocene. The sub-epoch lasted from 15.97 ± 0.05 Ma (million years ago) to 11.608 ± 0.005 Ma. During this period, a sharp drop in global temperatures took place. This event is known as the Middle Miocene disruption, Middle Miocene Climatic Transition. For the purpose of establishing European land mammal ages, this sub-epoch is equivalent to the Astaracian age. References External links GeoWhen Database - Middle Miocene Miocene, .02 Miocene geochronology, 02 Langhian, * Serravallian, * {{geochronology-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Journal Of South American Earth Sciences
The ''Journal of South American Earth Sciences'' is a peer-reviewed scientific journal published by Elsevier. It covers the earth sciences, primarily on issues that are relevant to South America, Central America, the Caribbean, Mexico, and Antarctica. The journal was established in 1988 and the editor-in-chief is James Kellogg (University of South Carolina). According to the ''Journal Citation Reports'', the journal has a 2012 impact factor of 1.533. See also *'' Ameghiniana'' *''Andean Geology ''Andean Geology'' (formerly ''Revista Geológica de Chile'') is a peer-reviewed scientific journal published three times per year by the National Geology and Mining Service, Chile's geology and mining agency. The journal covers the field of geo ...'' *'' Brazilian Journal of Geology'' *'' Latin American Journal of Sedimentology and Basin Analysis'' *'' Revista de la Asociación Geológica Argentina'' References External links * Geology journals Geology of South America Geolo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lycopsis
''Lycopsis'' is an extinct genus of South American metatherian that lived during the Miocene in Argentina and Colombia. History Although not named until 1927, Florentino Ameghino described a species now seen as synonymous with ''Lycopsis torresi'', ''Anatherium oxyrhynchus'', in 1895 based on a mandibular ramus with several teeth.Marshall, L. G. (1977). A new species of Lycopsis (Borhyaenidae: Marsupialia) from the La Venta fauna (Late Miocene) of Colombia, South America. ''Journal of Paleontology'', 633–642. The fossil was recovered from Puesto Estancia La Costa in Santa Cruz, Argentina, dating to the Miocene. The type material of ''Lycopsis'' was collected in July 1895 by "C. Berry" from the middle Miocene strata of the Santa Cruz Formation along the Santa Cruz River in the same area.Cabrera, Á. (1927). Datos para el conocimiento de los dasiuroideos fósiles argentinos. ''Revista del Museo de la Plata'', ''30'', 271–315. The fossils (MLP 11–113) were fragmentary, cons ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cladogram
A cladogram (from Greek language, Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an Phylogenetic tree, evolutionary tree because it does not show how ancestors are related to descendants, nor does it show how much they have changed, so many differing evolutionary trees can be consistent with the same cladogram. A cladogram uses lines that branch off in different directions ending at a clade, a group of organisms with a last common ancestor. There are many shapes of cladograms but they all have lines that branch off from other lines. The lines can be traced back to where they branch off. These branching off points represent a hypothetical ancestor (not an actual entity) which can be inferred to exhibit the traits shared among the terminal taxa above it. This hypothetical ancestor might then provide clues about the order of evolution of various features, adaptation, and other e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
La Venta (Colombia)
La Venta is a fossil locality located in the modern departments of Tolima and Huila in Colombia. This site is one of the richest Neogene fossil assemblages in South America and represents the best-known Cenozoic fossil site outside of Argentina. It provides a glimpse of what life in the region was like before the main wave of the Great American Interchange. Geology The fossils occur in Middle Miocene rocks of the Honda Group, which is divided into the younger Villavieja Formation and the older La Victoria Formation. The La Venta fauna contained ancient species of animal genera and families still alive today, as well as some entirely extinct prehistoric lineages. These animals lived some 13.8 to 12 million years ago in the Laventan age, which was named after La Venta. At that time, the climate of the region was wetter than today and there was much forest of trees similar (and probably related) to the ''sapino'' ('' Goupia glabra'') of our time. List of fauna Fossil anima ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basal (phylogenetics)
In phylogenetics, basal is the direction of the ''base'' (or root) of a phylogenetic tree#Rooted tree, rooted phylogenetic tree or cladogram. The term may be more strictly applied only to nodes adjacent to the root, or more loosely applied to nodes regarded as being close to the root. Note that extant taxa that lie on branches connecting directly to the root are not more closely related to the root than any other extant taxa. While there must always be two or more equally "basal" clades sprouting from the root of every cladogram, those clades may differ widely in taxonomic rank, Phylogenetic diversity, species diversity, or both. If ''C'' is a basal clade within ''D'' that has the lowest rank of all basal clades within ''D'', ''C'' may be described as ''the'' basal taxon of that rank within ''D''. The concept of a 'key innovation' implies some degree of correlation between evolutionary innovation and cladogenesis, diversification. However, such a correlation does not make a given ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phylogenetic Analysis
In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as phylogenetic inference. It infers the relationship among organisms based on empirical data and observed heritable traits of DNA sequences, protein amino acid sequences, and morphology. The results are a phylogenetic tree—a diagram depicting the hypothetical relationships among the organisms, reflecting their inferred evolutionary history. The tips of a phylogenetic tree represent the observed entities, which can be living taxa or fossils. A phylogenetic diagram can be rooted or unrooted. A rooted tree diagram indicates the hypothetical common ancestor of the taxa represented on the tree. An unrooted tree diagram (a network) makes no assumption about directionality of character state transformation, and does not show the origin or "root" of the taxa in question. In addition to their use for inferring phylogenetic patterns a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Premolar
The premolars, also called premolar Tooth (human), teeth, or bicuspids, are transitional teeth located between the Canine tooth, canine and Molar (tooth), molar teeth. In humans, there are two premolars per dental terminology#Quadrant, quadrant in the permanent teeth, permanent set of teeth, making eight premolars total in the mouth. They have at least two Cusp (dentistry), cusps. Premolars can be considered transitional teeth during chewing, or mastication. They have properties of both the canines, that lie anterior and molars that lie Posterior (anatomy), posterior, and so food can be transferred from the canines to the premolars and finally to the molars for grinding, instead of directly from the canines to the molars. Human anatomy The premolars in humans are the maxillary first premolar, maxillary second premolar, mandibular first premolar, and the mandibular second premolar. Premolar teeth by definition are permanent teeth Anatomical terms of location#Proximal and distal, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canine Tooth
In mammalian oral anatomy, the canine teeth, also called cuspids, dogteeth, eye teeth, vampire teeth, or fangs, are the relatively long, pointed teeth. In the context of the upper jaw, they are also known as '' fangs''. They can appear more flattened, however, causing them to resemble incisors and leading them to be called ''incisiform''. They developed and are used primarily for firmly holding food in order to tear it apart, and occasionally as weapons. They are often the largest teeth in a mammal's mouth. Individuals of most species that develop them normally have four, two in the upper jaw and two in the lower, separated within each jaw by incisors; humans and dogs are examples. In most species, canines are the anterior-most teeth in the maxillary bone. The four canines in humans are the two upper maxillary canines and the two lower mandibular canines. They are specially prominent in dogs (Canidae), hence the name. Details There are generally four canine teeth: two ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
