Perissodactyla is an order of ungulates. The order includes about 17 living species divided into three families: Equidae, Rhinocerotidae (rhinoceroses), and Tapiridae (tapirs). They typically have reduced the weight-bearing toes to three or one of the five original toes, though tapirs retain four toes on their front feet. The nonweight-bearing toes are either present, absent, vestigial, or positioned posteriorly. By contrast, artiodactyls bear most of their weight equally on four or two of the five toes: their third and fourth toes. Another difference between the two is that odd-toed ungulates digest plant cellulose in their intestines, rather than in one or more stomach chambers as even-toed ungulates, with the exception of Suina, do.
Pilgrimella is an extinct early Eocene genus of anthracobunid, a group of stem perissodactyls. It was a ground dwelling grazer with massive bilophodont molars Dental remains of this animal have been found in Chorlakki, Punjab province, Pakistan, and in the Subathu Formation in North-West India.
Condylarthra is an informal group – previously considered an order – of extinct placental mammals, known primarily from the Paleocene and Eocene epochs. They are considered early, primitive ungulates. It is now largely considered to be a wastebasket taxon, having served as a dumping ground for classifying ungulates which had not been clearly established as part of either Perissodactyla or Artiodactyla, being composed thus of several unrelated lineages.
The Chitarwata Formation is a geological formation in western Pakistan, made up of Oligocene and early Miocene terrestrial fluvial facies. The sediments were deposited in coastal depositional environments when Pakistan was partly covered by the Tethys Ocean.
Phenacodus is an extinct genus of mammals from the late Paleocene through middle Eocene, about 55 million years ago. It is one of the earliest and most primitive of the ungulates, typifying the family Phenacodontidae and the order Perissodactyla.
Tethytheria is a clade of mammals that includes the sirenians and proboscideans, as well as the extinct order Embrithopoda.
Panperissodactyla is a clade of ungulates containing living order Perissodactyla and all extinct ungulates more closely related to Perissodactyla than to Artiodactyla.
Archaeoceti, or Zeuglodontes in older literature, is a paraphyletic group of primitive cetaceans that lived from the Early Eocene to the late Oligocene. Representing the earliest cetacean radiation, they include the initial amphibious stages in cetacean evolution, thus are the ancestors of both modern cetacean suborders, Mysticeti and Odontoceti. This initial diversification occurred in the shallow waters that separated India and Asia 53 to 45 mya, resulting in some 30 species adapted to a fully oceanic life. Echolocation and filter-feeding evolved during a second radiation 36 to 35 mya.
Anthracobunidae is an extinct family of stem perissodactyls that lived in the early to middle Eocene period. They were originally considered to be a paraphyletic family of primitive proboscideans possibly ancestral to the Moeritheriidae and the desmostylians. The family has also thought to be ancestral to the Sirenia.
Anthracobune is an extinct genus of stem perissodactyl from the middle Eocene of the Upper Kuldana Formation of Kohat, Punjab, Pakistan.
Ishatherium is an extinct genus of ungulate from the early Eocene of the Subathu formation in northwestern India.
Lammidhania is an extinct genus of anthracobunids, which lived from the early to middle Eocene period. Its fossil remains were discovered in 1940 in the Chorlakki locality of the Punjab province of Pakistan.
Hsanotherium is an extinct genus of early ungulate from the middle Eocene, described in 2000 in the Pondaung Formation, Myanmar.
Paleontology or palaeontology is the study of prehistoric life forms on Earth through the examination of plant and animal fossils. This includes the study of body fossils, tracks (ichnites), burrows, cast-off parts, fossilised feces (coprolites), palynomorphs and chemical residues. Because humans have encountered fossils for millennia, paleontology has a long history both before and after becoming formalized as a science. This article records significant discoveries and events related to paleontology that occurred or were published in the year 1999.
Paleontology or palaeontology is the study of prehistoric life forms on Earth through the examination of plant and animal fossils. This includes the study of body fossils, tracks (ichnites), burrows, cast-off parts, fossilised feces (coprolites), palynomorphs and chemical residues. Because humans have encountered fossils for millennia, paleontology has a long history both before and after becoming formalized as a science. This article records significant discoveries and events related to paleontology that occurred or were published in the year 2000.
Meniscotherium is an extinct genus of dog-sized mammal which lived 54–38 million years ago. It was a herbivore and had hooves. Fossils have been found in Utah, New Mexico. and Colorado. Many individuals have been found together, indicating that it lived in groups.
Indobune is an extinct genus of ungulate endemic to Asia during the Eocene from 55.8—48.6 Ma, living for approximately 7.2 million years.
Obergfellia is an extinct genus of stem perissodactyl from the middle Eocene, discovered in 1980. Its known range includes northern India and Pakistan.
Jean-Paul Poirier is a French physicist and member of the French Academy of Sciences.
