Given the question: Information: - A continent is one of several very large landmasses on Earth. Generally identified by convention rather than any strict criteria, up to seven regions are commonly regarded as continents. Ordered from largest in size to smallest, they are: Asia, Africa, North America, South America, Antarctica, Europe, and Australia. In geology, areas of continental crust include regions covered with water. - The Oligocene is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present (to ). As with other older geologic periods, the rock beds that define the epoch are well identified but the exact dates of the start and end of the epoch are slightly uncertain. The name Oligocene comes from the Ancient Greek ("oligos", few) and ("kainos", new), and refers to the sparsity of extant forms of molluscs. The Oligocene is preceded by the Eocene Epoch and is followed by the Miocene Epoch. The Oligocene is the third and final epoch of the Paleogene Period. The Oligocene is often considered an important time of transition, a link between the archaic world of the tropical Eocene and the more modern ecosystems of the Miocene. Major changes during the Oligocene included a global expansion of grasslands, and a regression of tropical broad leaf forests to the equatorial belt. - The domestic goat ("Capra aegagrus hircus") is a subspecies of goat domesticated from the wild goat of southwest Asia and Eastern Europe. - A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthparts adapted to rasping or grinding. Horses and other herbivores have wide flat teeth that are adapted to grinding grass, tree bark, and other tough plant material. - The Whitneyan North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology (NALMA), typically set from 33,300,000 to 30,800,000 years BP, a period of . It is usually considered to fall within the Early Oligocene. The Whitneyan is preceded by the Orellan and followed by the Arikareean NALMA stages. - Leptauchenia is an extinct goat-like genus of terrestrial herbivore belonging to the oreodont family Merycoidodontidae, and the type genus of the tribe Leptaucheniini. The genus was endemic to North America during the Late Oligocene to Early Miocene (33.916.3 mya) and lived for approximately . - The Miocene is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words (', less) and (', new) and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene Epoch and is followed by the Pliocene Epoch. - Grasslands are areas where the vegetation is dominated by grasses (Poaceae), however sedge (Cyperaceae) and rush (Juncaceae) families can also be found. Grasslands occur naturally on all continents except Antarctica. Grasslands are found in most ecoregions of the Earth. For example, there are five terrestrial ecoregion classifications (subdivisions) of the temperate grasslands, savannas, and shrublands biome (ecosystem), which is one of eight terrestrial ecozones of the Earth's surface. - Sespia ("of Sespe Creek") is an extinct genus of oreodont, endemic to North America during the Whitneyan stage of the Oligocene-Late Oligocene epochs (30.824.8 mya) existing for approximately . - Leptaucheniinae ( '' Delicate Necks '' ) was a taxon of small , goat - like oreodonts with proportionally big heads found throughout North America during the Late Oligocene . Because skeletons of Leptauchenia and Sespia have been found by the literal thousands , they are often quoted as being the most numerous fossil mammals in North America during the Late Oligocene . They had high - crowned , hypsodont teeth which were used to chew gritty vegetation . Because the eyes and nostrils were placed high on the head , it was long assumed that Leptauchenia and Sespia were aquatic , or semi-aquatic animals . However , because their fossils have never been found in floodplain deposits or river channels , and their plague - like abundance in fossil sand dunes , Donald Prothero suggests that they were desert - dwelling animals . According to Prothero 's interpretation , the high - placed eyes and nostrils served to filter out sand while burrowing . - The Atlantic Ocean is the second largest of the world's oceans with a total area of about . It covers approximately 20 percent of the Earth's surface and about 29 percent of its water surface area. It separates the "Old World" from the "New World". - North America is a continent entirely within the Northern Hemisphere and almost all within the Western Hemisphere. It can also be considered a northern subcontinent of the Americas. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the west and south by the Pacific Ocean, and to the southeast by South America and the Caribbean Sea. - The Paleogene (or ; also spelled Palaeogene or Palogene; informally Lower Tertiary) is a geologic period and system that spans 43 million years from the end of the Cretaceous Period million years ago (Mya) to the beginning of the Neogene Period Mya. It is the beginning of the Cenozoic Era of the present Phanerozoic Eon. The Paleogene is most notable for being the time during which mammals diversified from relatively small, simple forms into a large group of diverse animals in the wake of the CretaceousPaleogene extinction event that ended the preceding Cretaceous Period. - Sespe Creek is a stream, some long, in Ventura County, southern California, in the Western United States. The creek starts at Potrero Seco in the eastern Sierra Madre Mountains, and is formed by more than thirty tributary streams of the Sierra Madre and Topatopa Mountains, before it empties into the Santa Clara River in Fillmore. What is the relationship between 'leptaucheniinae' and 'merycoidodontidae'?
The answer is:
parent taxon