The Pachydermata (meaning "thick skin") is an obsolete order of mammals described by Georges Cuvier and at one time recognised by many systematists. Because it is polyphyletic, the order Pachydermata is no longer in use, but it is important in the history of systematics. Although it is often described as an artificial grouping of unrelated mammals, it was recognised as a grade of hooved mammals to the exception of other Ungulates by zoologists such as Charles Darwin, and anatomical characters do support the affinities of "Pachyderm" mammals to each other and to other Ungulates. Scientific classification or biological classification refers to how biologists group and categorize extinct and living species of organisms. ... Subclasses Allotheria* Order Multituberculata (extinct) Order Volaticotheria (extinct) Order Palaeoryctoides (extinct) Order Triconodonta (extinct) Prototheria Order Monotremata Theria Infraclass Marsupialia Infraclass Eutheria The mammals are the class of vertebrate animals characterized by the production of milk in females for the nourishment of young, from mammary glands present on most species... Georges Cuvier Baron Georges Léopold Chrétien Frédéric Dagobert Cuvier (August 23, 1769–May 13, 1832) was a French naturalist and zoologist. ... In biology, a taxon is polyphyletic if it is descended from more than one root form (in Greek poly = many and phyletic = racial). ... A claw is a curved pointed growth found at the end of a toe or finger, or in arthropods, of the tarsus. ... Llamas such as this, which have two toes, are artiodactylas -- even toed ungulates Ungulates (meaning roughly hoofed or hoofed animal) make up several orders of mammals, of which six to eight survive. ... Zoology (Greek zoon = animal and logos = word) is the biological discipline which involves the study of animals. ... Charles Robert Darwin (12 February 1809 – 19 April 1882) was an eminent English naturalist who achieved lasting fame by convincing the scientific community that species develop over time from a common origin. ...

Cuvier's Pachydermata included the mammals now placed within Perissodactyla, Hyracoidea, and Proboscidea, as well as the Suina within Artiodactyla. Therefore modern "Pachydermata" would be represented by the horses and their relatives, the tapirs, the rhinoceroses, the elephants, the hippopotamuses, the peccaries and the pigs. Families Equidae Tapiridae Rhinocerotidae The odd-toed ungulates or Perissodactyla are large to very large browsing and grazing mammals with relatively simple stomachs and a large middle toe. ... Genera  Procavia  Heterohyrax  Dendrohyrax A hyrax is any of about 11 species of fairly small, thickset, herbivorous mammals in the order Hyracoidea. ... Groups Jozaria (extinct) Anthracobunidae (extinct) Moeritheriidae (extinct) Euproboscidea Numidotheriidae (extinct) Barytheriidae (extinct) Deinotheriidae (extinct) Elephantiformes Phiomiidae (extinct) Palaeomastodontidae (extinct) Hemimastodontidae (extinct) Euelephantoidea Choerolophodontidae (extinct) Amebelodontidae (extinct) Gnathabelodontidae (extinct) Gomphotheriidae (extinct) Elephantidae Mammutidae (extinct) Proboscidea is an order containing only one family of living animals, Elephantidae, the elephants, with three species... Families  Suidae  Tayassuidae  Hippopotamidae The Suina contains the earliest and most archaic Artiodactyla. ... Families Suidae Hippopotamidae Tayassuidae Camelidae Tragulidae Moschidae Cervidae Giraffidae Antilocapridae Bovidae The even-toed ungulates form the mammal order Artiodactyla. ... Binomial name Equus caballus Linnaeus, 1758 The horse (Equus caballus, sometimes seen as a subspecies of the Wild Horse, Equus ferus caballus) is a large odd-toed ungulate mammal, one of ten modern species of the genus Equus. ... Species Tapirus bairdii Tapirus indicus Tapirus pinchaque Tapirus terrestris Tapirs are large browsing mammals, roughly pig-like in shape, with short, prehensile snouts. ... Genera Ceratotherium Dicerorhinus Diceros Rhinoceros Coelodonta (extinct) Elasmotherium (extinct) Height Comparison of Extant Rhinoceros Species. ... Genera and Species Loxodonta Loxodonta cyclotis Loxodonta africana Elephas Elephas maximus Elephas antiquus † Elephas beyeri † Elephas celebensis † Elephas cypriotes † Elephas ekorensis † Elephas falconeri † Elephas iolensis † Elephas planifrons † Elephas platycephalus † Elephas recki † Stegodon † Mammuthus † Elephantidae (the elephants) is a family of pachyderm, and the only remaining family in the order Proboscidea... Binomial name Hippopotamus amphibius Linnaeus, 1758 The Hippopotamus (Hippopotamus amphibius), from the Greek ‘ιπποπόταμος (hippopotamos, hippos meaning horse and potamos meaning river), is a large, plant-eating African mammal, one of only two extant, and three or four recently extinct, species in the family Hippopotamidae. ... Species Tayassu Tayassu tajacu Tayassu pecari Catagonus Catagonus wagneri The peccaries (also known by its Spanish name, javelina or pecarí) are medium-sized mammals of the family Tayassuidae. ... This article is about the pig genus. ...

The term "pachyderm" is now often being used to describe a proboscid, like an elephant. Groups Jozaria (extinct) Anthracobunidae (extinct) Moeritheriidae (extinct) Euproboscidea Numidotheriidae (extinct) Barytheriidae (extinct) Deinotheriidae (extinct) Elephantiformes Phiomiidae (extinct) Palaeomastodontidae (extinct) Hemimastodontidae (extinct) Euelephantoidea Choerolophodontidae (extinct) Amebelodontidae (extinct) Gnathabelodontidae (extinct) Gomphotheriidae (extinct) Elephantidae Mammutidae (extinct) Proboscidea is an order containing only one family of living animals, Elephantidae, the elephants, with three species... Genera and Species Loxodonta Loxodonta cyclotis Loxodonta africana Elephas Elephas maximus Elephas antiquus † Elephas beyeri † Elephas celebensis † Elephas cypriotes † Elephas ekorensis † Elephas falconeri † Elephas iolensis † Elephas planifrons † Elephas platycephalus † Elephas recki † Stegodon † Mammuthus † Elephantidae (the elephants) is a family of pachyderm, and the only remaining family in the order Proboscidea...