Paleocene first appearances

Gastornis is an extinct genus of large, flightless birds that lived during the mid-Paleocene to mid-Eocene epochs of the Paleogene period. Most fossils have been found in Europe, and some species typically referred to the genus are known from North America and Asia. Several genera, including the well-studied genus Diatryma, have historically been considered junior synonyms of Gastornis. However, this interpretation has been challenged recently, and some researchers currently consider Diatryma to be a valid genus.

Mesonychia ("middle claws") is an extinct taxon of small to large-sized carnivorous ungulates related to artiodactyls. Mesonychians first appeared in the Early Paleocene, went into a sharp decline at the end of the Eocene, and died out entirely when the last genus, Mongolestes, became extinct in the Early Oligocene. In Asia, the record of their history suggests they grew gradually larger and more predatory over time, then shifted to scavenging and bone-crushing lifestyles before the group became extinct.

Plesiadapiformes ("Adapid-like" or "near Adapiformes") is an extinct basal pan-primates group, as sister to the rest of the pan-primates. The pan-primates together with the Dermoptera form the Primatomorpha. Purgatorius may not be a primate as an extinct sister to the rest of the Dermoptera or a separate, more basal stem pan-primate branch. Even with Purgatorius removed, the crown primates may even have emerged in this group. left|thumb|The plesiadapiform Plesiadapis|Plesiadapis cookei (right), compared to [[Notharctus tenebrosus (left), an early crown primate. Both come from Eocene Wyoming, t

Notoungulata is an extinct order of ungulates that inhabited South America from the early Paleocene to the end of the Pleistocene, living from approximately 61 million to 11,000 years ago. Notoungulates were morphologically diverse, with forms resembling animals as disparate as rabbits and rhinoceroses. Notoungulata are the largest group of South American native ungulates, with over 150 genera in 14 families having been described, divided into two major subgroupings, Typotheria and Toxodontia. Notoungulates first diversified during the Eocene. Their diversity declined from the late Neogene onw

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.

Dinocerata, from Ancient Greek (), "terrible", and (), "horn", or Uintatheria, is an extinct order of large herbivorous hoofed mammals with horns and protuberant canine teeth, known from the Paleocene and Eocene of Asia and North America. With body masses ranging up to they represent some of the earliest known large mammals.

Pantodonta is an extinct order (or, according to some, an suborder) of eutherian mammals. These herbivorous mammals were one of the first groups of large mammals to evolve (around 66 million years ago) after the end of the Cretaceous. The last pantodonts died out at the end of the Eocene (around 34 million years ago).

Astrapotheria is an extinct order of South American and Antarctic hoofed mammals that existed from the late Paleocene to the Middle Miocene, . Astrapotheres were large, rhinoceros-like animals and have been called one of the most bizarre orders of mammals with an enigmatic evolutionary history.

Coryphodon (from Greek , "point", and , "tooth", meaning peaked tooth, referring to "the development of the angles of the ridges into points [on the molars].") is an extinct genus of pantodonts of the family Coryphodontidae.

Omomyidae is a group of early primates that radiated during the Eocene epoch between about (mya). Fossil omomyids are found in North America, Europe & Asia, making it one of two groups of Eocene primates with a geographic distribution spanning holarctic continents, the other being the adapids (family Adapidae). Early representatives of the Omomyidae and Adapidae appear suddenly at the beginning of the Eocene (56 mya) in North America, Europe, and Asia, and are the earliest known crown primates.

Pyrotheria (from Ancient Greek πῦρ (pûr), meaning "fire", and θηρίον (theríon), meaning "beast") is an order of extinct meridiungulate mammals. These elephant-like ungulates include the genera Baguatherium, Carolozittelia, Colombitherium, Griphodon, Propyrotherium, Proticia, and Pyrotherium.

Xenungulata ("strange ungulates") is an order of extinct and primitive South American hoofed mammals that lived from the Late Paleocene to Early Eocene (Itaboraian to Casamayoran in the SALMA classification). Fossils of the order are known from deposits in Brazil, Argentina, Peru, and Colombia. The best known member of this enigmatic order is the genus Carodnia, a tapir-like and -sized animal with a gait similar to living African elephants.

Mesonychidae (meaning "middle claws") is an extinct family of small to large-sized omnivorous-carnivorous mammals. They were endemic to North America and Eurasia during the Early Paleocene to the Early Oligocene, and were the earliest group of large carnivorous mammals in Asia. Once considered a sister-taxon to artiodactyls, recent evidence now suggests no close connection to any living mammal. Mesonychid taxonomy has long been disputed and they have captured popular imagination as "wolves on hooves", animals that combine features of both ungulates and carnivores. Skulls and teeth have similar

Tillodontia is an extinct suborder of eutherian mammals known from the Early Paleocene to Late Eocene of China, the Late Paleocene to Middle Eocene of North America where they display their maximum species diversity, the Middle Eocene of Pakistan, and the Early Eocene of Europe. Leaving no descendants, they are most closely related to the pantodonts, another extinct group. The tillodonts were medium- to large-sized animals that probably fed on roots and tubers in temperate to subtropical habitats.

Viverravidae ("ancestors of viverrids") is an extinct monophyletic family of mammals from extinct superfamily Viverravoidea within the clade Carnivoramorpha, that lived from the early Palaeocene to the late Eocene in North America, Europe and Asia. They were once thought to be the earliest carnivorans and ancestral to extant ones, but now are placed outside the order Carnivora based on cranial morphology as relatives (a plesion-group) to extant carnivorans.

Toxodontia is a suborder of the meridiungulate order Notoungulata. Most of the members of the five included families, including the largest notoungulates, share several dental, auditory and tarsal specializations. The group is named after Toxodon, the first example of the group to be discovered by science.

Phenacodontidae is an extinct family of large herbivorous mammals traditionally placed in the "wastebasket taxon" Condylarthra, which may instead represent early-stage perissodactyls. They lived from the late early Paleocene to early middle Eocene (about 60–50 million years ago) and their fossil remains have been found in North America and Europe. The only unequivocal Asian phenacodontid is Lophocion asiaticus.

Hapalodectidae (literal translation 'soft biters': ('soft, tender'), ('biter')) is an extinct family of relatively small-bodied () mesonychian placental mammals from the Paleocene and Eocene of North America and Asia. Hapalodectids differ from the larger and better-known mesonychids by having teeth specialized for cutting (presumably meat), while the teeth of other mesonychids, such as Mesonyx or Sinonyx, are more specialized for crushing bones. Hapalodectids were once considered a subfamily of the Mesonychidae, but the discovery of a skull of Hapalodectes hetangensis showed additional differe

Periptychidae is a family of Cretaceous–Paleocene placental mammals, known definitively only from North America. The family is part of a radiation of early herbivorous and omnivorous mammals formerly classified in the extinct order "Condylarthra", which may be related to some or all living ungulates (hoofed mammals). Periptychids are distinguished from other "condylarths" by their teeth, which have swollen premolars and unusual vertical enamel ridges. The family includes both large and small genera, with the larger forms having robust skeletons. Known skeletons of periptychids suggest generali

Plesiadapidae is a family of plesiadapiform mammals related to primates known from the Paleocene and Eocene of North America, Europe, and Asia. Plesiadapids were abundant in the late Paleocene, and their fossils are often used to establish the ages of fossil faunas.

Pholidotamorpha ("pangolin-like forms") is a clade of placental, mostly ant- and termite-eating mammals that (partially) physically resemble anteaters and armadillos. However, those aforementioned species are now placed in the order Xenarthra, along with sloths; Pholidotamorpha is now classified under the mirorder Ferae, which includes the order Carnivora (carnivorous mammals) and the pangolins (Pholidota) as well as the prehistoric order Palaeanodonta, containing only extinct species.

Proterotheriidae is an extinct family of litoptern ungulates known from the Eocene-Late Pleistocene of South America. Members of the group were small to medium-sized cursorial herbivores with brachydont teeth, with their toes showing progressive reduction, with later members of the group bearing weight on a single large toe similar to living horses.

Sebecidae is an extinct family of prehistoric terrestrial sebecosuchian crocodylomorphs, known from the Late Cretaceous and Cenozoic of Europe, South America and the Caribbean. They were the latest surviving group of non-crocodilian crocodylomorphs.

Didolodontidae is a possibly paraphyletic family of "condylarth" mammals known from the Paleogene of South America, with most specimens known from Argentina. They were generally small-medium in body size, and had a bunodont dentition. A close relationship with litopterns has been suggested by some studies. They range in age from the early Paleocene (Selandian/Peligran) to late Eocene (Priabonian/Mustersan). The attribution of Salladolodus deuterotheroides from the Late Oligocene of Bolivia to the family is doubtful.

Triisodontidae is an extinct, probably paraphyletic, or possibly invalid family of mesonychian placental mammals. Most triisodontid genera lived during the Paleocene in North America, but the genus Andrewsarchus (if it is a mesonychian, and not an artiodactyl) is known from the middle Eocene of Asia. Triisodontids were the first relatively large predatory mammals to appear in North America following the extinction of the non-bird dinosaurs. They differ from other mesonychian families in having less highly modified teeth.

Coryphodontidae is an extinct family of pantodont mammals known from the Late Paleocene to the Middle Eocene of Eurasia and North America.

Numidotheriidae is an extinct family of primitive proboscideans that lived from the late Paleocene to the early Oligocene periods of North Africa.

Isotemnidae is a paraphyletic extinct family of notoungulate mammals known from the Paleocene (Las Flores Formation, Itaboraian) to Middle Miocene (Honda Group, Laventan) of South America.

Palaeonictis ("ancient weasel") is an extinct genus of placental mammals from extinct subfamily Palaeonictinae within extinct family Oxyaenidae, that lived in Europe and North America from the late Paleocene to the early Eocene.

Epoicotheriidae ("strange beasts") is an extinct paraphyletic family of insectivorous placental mammals within extinct order Palaeanodonta, that lived in North America, Asia and Europe from the middle Paleocene to early Oligocene. Epoicotheriids were fossorial mammals. Late Eocene/early Oligocene genera were highly specialized animals that were convergent with the talpids, golden moles and marsupial mole in the structure of their skulls and forelimbs, and would have had a similar lifestyle as subterranean burrowers. They are considered among the most specialized animals that have ever evolved

Diplocynodon is an extinct genus of eusuchian, either an alligatoroid crocodilian or a stem-group crocodilian, that lived during the Paleocene to Middle Miocene in Europe. Some species may have reached lengths of , while others probably did not exceed . They are almost exclusively found in freshwater environments. The various species are thought to have been opportunistic aquatic predators.

Henricosborniidae is a family of extinct notoungulate mammals known from the Late Paleocene to Middle Eocene of Argentina, Bolivia and Brazil. The name honors U.S. paleontologist Henry Fairfield Osborn.

Discoaster is a genus of extinct star-shaped marine algae, with calcareous exoskeletons of between 5-40 μm across that are abundant as nanofossils in tropical deep-ocean deposits of Neogene age. Discoaster belongs to the haptophytes. About 100 species can be recognized.

Mixodectidae, from Ancient Greek μιξο (mixo) "mixed", and δεκτες (dektes) "biter", is an extinct family of insectivorous placental mammals in the order Dermoptera. The mixodectids originated in the late Cretaceous and survived into the Paleocene in Europe and North America.

Planocraniidae is an extinct family of eusuchian crocodyliforms known from the Paleogene of Asia, Europe and North America. The family was coined by Li in 1976, and contains three genera, Boverisuchus, Duerosuchus and Planocrania. Planocraniids were highly specialized crocodyliforms that were adapted to living on land. They had extensive body armor, long legs, and blunt claws resembling hooves, and are sometimes informally called "hoofed crocodiles".

Alagomyidae is a family of rodents known from the late Paleocene and early Eocene of Asia and North America (McKenna and Bell, 1997). Alagomyids have been identified as the most basal rodents, lying outside the common ancestry of living forms (Meng et al., 1994). Because of their phylogenetic position and their conservative dental morphology, alagomyids have played a key role in investigations of the origins and relationships of rodents (Meng et al., 1994; Meng and Wyss, 2001).

Adapisoriculidae is an extinct family of non-placental eutherian mammals which was present during the Paleogene and possibly the Late Cretaceous. They were once thought to be members of the order Erinaceomorpha, closely related to the hedgehog family (Erinaceidae), because of their similar dentition, or to be basal Euarchontans. They were also thought to be marsupials at one point. Most recent studies show them to be non-placental eutherians, however.

Prolimnocyon ("before Limnocyon") is an extinct paraphyletic genus of limnocyonin hyaenodonts that lived in Asia and North America during the Late Paleocene to Middle Eocene. Prolimnocyon chowi is one of the earliest known member of the order Hyaenodonta and clade Limnocyoninae.

The Sophiornithidae (literally "wisdom birds") are an extinct family of chicken-sized predatory birds that lived from the Paleocene to the Eocene periods of the Cenozoic, and were found primarily in Europe, and are thought to be primitive owls (hence, the name wisdom bird). They were also possibly related to Strigiformes.

Archaeohyracidae is an extinct family of notoungulate mammals known from the Paleocene through the Oligocene of South America. First named in 1897, it is now thought to be paraphyletic, rather than a genuine group of closely related animals with a single, unique, ancestor.

Carpolestidae is a family of primate-like Plesiadapiformes that were prevalent in North America and Asia from the mid Paleocene through the early Eocene. Typically, they are characterized by two large upper posterior premolars and one large lower posterior premolar. They weighed about 20-150g, and were about the size of a mouse. Though they come from the order, Plesiadapiformes, that may have given rise to the primate order, carpolestids are too specialized and derived to be ancestors of primates.

Bemalambda (meaning "stepped lambda") is a genus of extinct mammal, belonging to the pantodonts. It lived in the lower-middle Paleocene (about 63–58 million years ago) and the fossil remains have been found in China.

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Lazarussuchus (meaning "Lazarus's crocodile") is an extinct genus of amphibious reptile, known from the Cenozoic of Europe. It is the youngest known member of Choristodera, an extinct order of aquatic reptiles that first appeared in the Middle Jurassic. Fossils have been found in Late Paleocene, Late Oligocene, Early Miocene and possibly Late Miocene deposits (~56-20 or possibly 11.6 million years ago) in France, Germany, and the Czech Republic. Two species have been named: the type species L. inexpectatus ("unexpected") (Hecht, 1992) from the late Oligocene of France. and L. dvoraki from the

Eurymylidae is a family of extinct simplicidentates. Most authorities consider them to be basal to all modern rodents and suggest they may have been the ancestral stock from which the most recent common ancestor of all modern rodents (crown rodents) arose. However, the better-known eurymylids, including Eurymylus, Heomys, Matutinia, and Rhombomylus, appear to represent a monophyletic side branch that is that is that is not directly ancestral to rodents (Meng et al., 2003). Huang et al. (2004) have argued that Hanomys, Matutinia, and Rhombomylus form a clade characterized by distinctive feature

Plesiadapoidea was an extinct superfamily of primates that existed during the Paleocene and Eocene in North America, Europe, and Asia.

Tytthaena ("little hyena") is an extinct genus of placental mammals from extinct subfamily Tytthaeninae within extinct family Oxyaenidae, that lived in North America from the late Paleocene to early Eocene.

Peltephilidae (meaning "armor-liking") is a family of South American cingulates (armadillos) that lived for over 40 million years, but peaked in diversity towards the end of the Oligocene and beginning of the Miocene in what is now Argentina. They were exclusive to South America due to its geographic isolation at the time, one of many of the continent's strange endemic families. Peltephilids are one of the earliest known cingulates, diverging from the rest of Cingulata in the Early Eocene.

Bemalambdidae is an extinct family of pantodont mammals known from Early and Middle Paleocene of China.

Arctocyonians (Arctocyonia; also known as "Procreodi") (from Ancient Greek ἄρκτος (árktos), meaning "bear", and κύων (kúon), meaning "dog", and thus, "bear-dog") are a clade of laurasiatherian mammals whose stratigraphic range runs from the Palaeocene to the Early Eocene epochs. They were among the earliest examples of major mammalian predators after the Cretaceous–Paleogene extinction event. While some classify arctocyonians as stem-artiodactyls, others have classified the group as members of Ferae. There are three families classified in the order: Arctocyonidae, Oxyclaenidae, and Quettacyoni

Clavilithes is an extinct genus of fossil sea snails, marine gastropod mollusks in the family Fasciolariidae, the tulip snails and spindle snails.

thumb|right|upright|Dinopanorpa megarche holotype Dinopanorpidae is a small family of extinct insects in the order Mecoptera (scorpionflies) that contains two genera and seven species.

Muriwaimanu is an extinct genus of early penguin from the Paleocene Waipara Greensand of New Zealand. Only the type species M. tuatahi is known.

Peradectidae is a family of small metatherian mammals, spanning from the Paleocene (or possibly Latest Cretaceous) to the Miocene. Fossils are known from the Northern Hemisphere, including Europe, Asia and North America. The monophyly of the group has been questioned, with some authors suggesting that Peradectes should be the only genus placed in the family. The morphology of peradectids has been considered to be similar to opossums, with at least some exhibiting morphology suggesting a tree dwelling arboreal/scansorial lifestyle. Their diet is suggested to have included insects and fruit.

Sveltia is a genus in the subfamily Cancellariinae of the nutmeg sea snails with an extensive fossil range.

Aturia is an extinct genus of Paleocene to Miocene nautilids within Aturiidae, a monotypic family, established by Campman in 1857 for Aturia Bronn, 1838, and is included in the superfamily Nautilaceae in Kümmel 1964.

Oldfieldthomasiidae is an extinct family of notoungulate mammals known from the Late Paleocene to Late Eocene of South America. The family was classified by George Gaylord Simpson in 1945 and a synonym is Acoelodidae, defined by Florentino Ameghino in 1901.