The Cenozoic is Earth's current geological era, representing the last 66 million years of Earth's history. It is characterized by the dominance of insects, mammals, birds and angiosperms. It is the latest of three geological eras of the Phanerozoic Eon, preceded by the Mesozoic and Paleozoic. The Cenozoic started with the Cretaceous–Paleogene extinction event, when many species, including the non-avian dinosaurs, became extinct in an event attributed by most experts to the impact of a large asteroid or other celestial body, the Chicxulub impactor.
A mammoth is any species of the extinct elephantid genus Mammuthus. They lived from the late Miocene epoch into the Holocene until about 4,000 years ago, with mammoth species at various times inhabiting Africa, Asia, Europe, and North America. Mammoths are distinguished from living elephants by their spirally twisted tusks and in at least some later species, the development of numerous adaptions to living in cold environments, including a thick layer of fur.
Extinction is the termination of a taxon by the death of its last member. A taxon may become functionally extinct before the death of its last member if it loses the capacity to reproduce and recover. Because a species' potential range may be very large, determining this moment is difficult, and is usually done retrospectively. This difficulty leads to phenomena such as Lazarus taxa, where a species presumed extinct abruptly "reappears" after a period of apparent absence.
The dire wolf is an extinct canine. The dire wolf lived in the Americas during the Late Pleistocene and Early Holocene epochs. The species was named in 1858, four years after the first specimen had been found. Two subspecies are recognized: Aenocyon dirus guildayi and Aenocyon dirus dirus. The largest collection of its fossils has been obtained from the Rancho La Brea Tar Pits in Los Angeles.
Neontology is a part of biology that, in contrast to paleontology, deals with living organisms. It is the study of extant taxa : taxa with members still alive, as opposed to (all) being extinct. For example:
The Late Pleistocene is an unofficial age in the international geologic timescale in chronostratigraphy, also known as the Upper Pleistocene from a stratigraphic perspective. It is intended to be the fourth division of the Pleistocene Epoch within the ongoing Quaternary Period. It is currently defined as the time between c. 129,000 and c. 11,700 years ago. The late Pleistocene equates to the proposed Tarantian Age of the geologic time scale, preceded by the officially ratified Chibanian. The beginning of the Late Pleistocene is the transition between the end of the Penultimate Glacial Period and the beginning of the Last Interglacial around 130,000 years ago. The Late Pleistocene ends with the termination of the Younger Dryas, some 11,700 years ago when the Holocene Epoch began.
Chendytes lawi is an extinct, goose-sized flightless marine duck, once common on the California coast, the California Channel Islands, and possibly southern Oregon. It lived in the Pleistocene and survived into the Holocene. It appears to have gone extinct at about 450–250 BCE. The youngest direct radiocarbon date from a Chendytes bone fragment dates to 770–400 BCE and was found in an archeological site in Ventura County. Its remains have been found in fossil deposits and in early coastal archeological sites. Archeological data from coastal California show a record of human exploitation of Chendytes lawi for at least 8,000 years. It was probably driven to extinction by hunting, animal predation, and loss of habitat. Chendytes bones have been identified in archaeological assemblages from 14 coastal sites, including two on San Miguel Island and 12 in mainland localities. Hundreds of Chendytes bones and egg shells found in Pleistocene deposits on San Miguel Island have been interpreted as evidence that some of these island fossil localities were nesting colonies, one of which Guthrie dated to about 12,000 14C years. There is nothing in the North American archaeological record indicating a span of exploitation for any megafaunal genus remotely as long as that of Chendytes.
Francis Clark Howell, generally known as F. Clark Howell, was an American anthropologist.
Peritresius is an extinct genus of sea turtle from the Late Cretaceous deposits in the US Eastern Seaboard.
Sinopa is an extinct genus of placental mammals from extinct family Sinopidae within extinct order Hyaenodonta, that lived in North America and Asia from the early to middle Eocene.
Parietobalaena is an extinct genus of baleen whale, belonging to the family Pelocetidae. Fossils are found in Miocene-aged marine strata in North America, Europe, Australia, and Japan, including the Temblor and Itahashi formations. Based on previous estimates of juvenile specimens, Tsai (2017) suggested a body size of 12-15 m for P. yamaokai, akin to that of the gray whale.
Obamadon is an extinct genus of polyglyphanodontian lizards from the Late Cretaceous of North America. Fossils have been found in the Hell Creek Formation of Montana and the Lance Formation of Wyoming. Researchers describe it as being distinguished by its "tall, slender teeth with large central cusps separated from small accessory cusps by lingual grooves." The type species was named Obamadon gracilis after United States president Barack Obama, "in reference to the tall, straight teeth, and the manner in which Mr. Obama has acted as a role model of good oral hygiene for the world." According to Nicholas R. Longrich of Yale University, the species "was probably a foot long, [and] with these tall, slender teeth it used to eat insects and plant matter."
Araeosteus is an extinct genus of marine ray-finned fish, closely related to the modern-day prowfish. It contains a single species, A. rothi which is known from Late Miocene (Tortonian)-aged marine strata in Southern California, primarily the Diatom Beds of Lompoc and the Santa Monica Mountains.
Hildegarde Howard was an American pioneer in paleornithology. She was mentored by the famous ornithologist, Joseph Grinnell, at the Museum of Vertebrate Zoology (MVZ) and in avian paleontology. She was well known for her discoveries in the La Brea Tar Pits, among them the Rancho La Brea eagles. She discovered and described Pleistocene flightless waterfowl at the prehistoric Ballona wetlands of coastal Los Angeles County at Playa del Rey. In 1953, Howard became the third woman to be awarded the Brewster Medal. She was the first woman president of the Southern California Academy of Sciences. Hildegarde wrote 150 papers throughout her career.
Plesiocetus is a genus of extinct rorquals found worldwide. It has had a chequered taxonomic history, having served as a wastebasket genus for a handful of mysticete species.
Joseph Richard Slevin was an American herpetologist and the second curator of herpetology at the California Academy of Sciences, with which he was affiliated for over 50 years. He collected reptile and amphibian specimens from around the world, notably in the Galápagos Islands in a 17-month expedition, and was largely responsible for re-growing the academy's herpetological collection following its destruction in the 1906 San Francisco earthquake. He wrote or co-wrote nearly 60 scientific papers, and is commemorated in the scientific names of over a dozen species or subspecies of animals and plants.
Hyperailurictis is an extinct genus of felid from Miocene North America. The Hyperailurictis species are Pseudaelurus-grade felids and thought to be the first felids in the Americas.
Lophocetus is an extinct genus of dolphin belonging to the clade Delphinida that is known from late Miocene (Tortonian) marine deposits in California and Maryland. Although usually placed in Kentriodontidae, recent studies have found it only distantly related to Kentriodon.
Dioplotherium is an extinct genus of mammal known from Neogene deposits in the Southeastern United States.
Chelonoidis niger phantasticus is a subspecies of Galápagos tortoise that was discovered in 1906 and thought extinct, until a single female was discovered living on Fernandina Island by an expedition in February 2019. In May 2021, a genetic test carried out by scientists from the California Academy of Sciences confirmed that the single female tortoise discovered in 2019 is from the subspecies Chelonoidis niger phantasticus. The subspecies name has often been misspelled as phantastica, an error introduced in the 1980s when Chelonoidis was elevated to genus and mistakenly treated as feminine, an error recognized and fixed in 2017.
