Morocco the Kingdom of Morocco, is a country located in the Maghreb region of North West Africa with an area of 710,850 km2. Its capital is the largest city Casablanca, it overlooks the Mediterranean Sea to the Atlantic Ocean to the west. Morocco claims the areas of Ceuta, Melilla and Peñón de Vélez de la Gomera, all of them under Spanish jurisdiction. Since the foundation of the first Moroccan state by Idris I in 788 AD, the country has been ruled by a series of independent dynasties, reaching its zenith under the Almoravid and Almohad dynasties, spanning parts of Iberia and northwestern Africa; the Marinid and Saadi dynasties continued the struggle against foreign domination, allowing Morocco to remain the only northwest African country to avoid Ottoman occupation. The Alaouite dynasty, which rules to this day, seized power in 1631. In 1912, Morocco was divided into French and Spanish protectorates, with an international zone in Tangier, it regained its independence in 1956, has since remained comparatively stable and prosperous by regional standards.
Morocco claims the non-self-governing territory of Western Sahara Spanish Sahara, as its Southern Provinces. After Spain agreed to decolonise the territory to Morocco and Mauritania in 1975, a guerrilla war arose with local forces. Mauritania relinquished its claim in 1979, the war lasted until a cease-fire in 1991. Morocco occupies two thirds of the territory, peace processes have thus far failed to break the political deadlock; the unitary sovereign state of Morocco is a constitutional monarchy with an elected parliament. The King of Morocco holds vast executive and legislative powers over the military, foreign policy and religious affairs. Executive power is exercised by the government, while legislative power is vested in both the government and the two chambers of parliament, the Assembly of Representatives and the Assembly of Councillors; the king can issue decrees called dahirs. He can dissolve the parliament after consulting the Prime Minister and the president of the constitutional court.
Morocco's predominant religion is Islam, its official languages are Arabic and Berber. E; the Moroccan dialect of Arabic, referred to as Darija, French are widely spoken. Moroccan culture is a blend of Berber, Sephardi Jews, West African and European influences. Morocco is a member of the Union for the Mediterranean and the African Union, it has the fifth largest economy of Africa. The full Arabic name al-Mamlakah al-Maghribiyyah translates to "Kingdom of the West". For historical references, medieval Arab historians and geographers sometimes referred to Morocco as al-Maghrib al-Aqṣá to distinguish it from neighbouring historical regions called al-Maghrib al-Awsaṭ and al-Maghrib al-Adná; the basis of Morocco's English name is Marrakesh, its capital under the Almoravid dynasty and Almohad Caliphate. The origin of the name Marrakesh is disputed, but is most from the Berber words amur akush or "Land of God"; the modern Berber name for Marrakesh is Mṛṛakc. In Turkish, Morocco is known as a name derived from its ancient capital of Fes.
However, this was not the case in other parts of the Islamic world: until the middle of the 20th century, the common name of Morocco in Egyptian and Middle Eastern Arabic literature was Marrakesh. The English name Morocco is an anglicisation of the Spanish "Marruecos", from which derives the Tuscan "Morrocco", the origin of the Italian "Marocco"; the area of present-day Morocco has been inhabited since Paleolithic times, sometime between 190,000 and 90,000 BC. A recent publication may demonstrate an earlier habitation period, as Homo sapiens fossils discovered in the late 2000s near the Atlantic coast in Jebel Irhoud were dated to 315,000 years before present. During the Upper Paleolithic, the Maghreb was more fertile than it is today, resembling a savanna more than today's arid landscape. Twenty-two thousand years ago, the Aterian was succeeded by the Iberomaurusian culture, which shared similarities with Iberian cultures. Skeletal similarities have been suggested between the Iberomaurusian "Mechta-Afalou" burials and European Cro-Magnon remains.
The Iberomaurusian was succeeded by the Beaker culture in Morocco. Mitochondrial DNA studies have discovered the Saami of Scandinavia; this supports theories that the Franco-Cantabrian refuge area of southwestern Europe was the source of late-glacial expansions of hunter-gatherers who repopulated northern Europe after the last ice age. Northwest Africa and Morocco were drawn into the wider emerging Mediterranean world by the Phoenicians, who established trading colonies and settlements in the early Classical period. Substantial Phoenician settlements were at Chellah and Mogador. Mogador was a Phoenician colony as early as the early 6th century BC. Morocco became a realm of the Northwest African civilisation of ancie
The Precambrian is the earliest part of Earth's history, set before the current Phanerozoic Eon. The Precambrian is so named because it preceded the Cambrian, the first period of the Phanerozoic eon, named after Cambria, the Latinised name for Wales, where rocks from this age were first studied; the Precambrian accounts for 88% of the Earth's geologic time. The Precambrian is an informal unit of geologic time, subdivided into three eons of the geologic time scale, it spans from the formation of Earth about 4.6 billion years ago to the beginning of the Cambrian Period, about 541 million years ago, when hard-shelled creatures first appeared in abundance. Little is known about the Precambrian, despite it making up seven-eighths of the Earth's history, what is known has been discovered from the 1960s onwards; the Precambrian fossil record is poorer than that of the succeeding Phanerozoic, fossils from the Precambrian are of limited biostratigraphic use. This is because many Precambrian rocks have been metamorphosed, obscuring their origins, while others have been destroyed by erosion, or remain buried beneath Phanerozoic strata.
It is thought that the Earth coalesced from material in orbit around the Sun at 4,543 Ma, may have been struck by a large planetesimal shortly after it formed, splitting off material that formed the Moon. A stable crust was in place by 4,433 Ma, since zircon crystals from Western Australia have been dated at 4,404 ± 8 Ma; the term "Precambrian" is recognized by the International Commission on Stratigraphy as the only "supereon" in geologic time. "Precambrian" is still used by geologists and paleontologists for general discussions not requiring the more specific eon names. As of 2010, the United States Geological Survey considers the term informal, lacking a stratigraphic rank. A specific date for the origin of life has not been determined. Carbon found in 3.8 billion-year-old rocks from islands off western Greenland may be of organic origin. Well-preserved microscopic fossils of bacteria older than 3.46 billion years have been found in Western Australia. Probable fossils 100 million years older have been found in the same area.
However, there is evidence. There is a solid record of bacterial life throughout the remainder of the Precambrian. Excluding a few contested reports of much older forms from North America and India, the first complex multicellular life forms seem to have appeared at 1500 Ma, in the Mesoproterozoic era of the Proterozoic eon. Fossil evidence from the Ediacaran period of such complex life comes from the Lantian formation, at least 580 million years ago. A diverse collection of soft-bodied forms is found in a variety of locations worldwide and date to between 635 and 542 Ma; these are referred to as Vendian biota. Hard-shelled creatures appeared toward the end of that time span, marking the beginning of the Phanerozoic eon. By the middle of the following Cambrian period, a diverse fauna is recorded in the Burgess Shale, including some which may represent stem groups of modern taxa; the increase in diversity of lifeforms during the early Cambrian is called the Cambrian explosion of life. While land seems to have been devoid of plants and animals and other microbes formed prokaryotic mats that covered terrestrial areas.
Tracks from an animal with leg like appendages have been found in what was mud 551 million years ago. Evidence of the details of plate motions and other tectonic activity in the Precambrian has been poorly preserved, it is believed that small proto-continents existed prior to 4280 Ma, that most of the Earth's landmasses collected into a single supercontinent around 1130 Ma. The supercontinent, known as Rodinia, broke up around 750 Ma. A number of glacial periods have been identified going as far back as the Huronian epoch 2400–2100 Ma. One of the best studied is the Sturtian-Varangian glaciation, around 850–635 Ma, which may have brought glacial conditions all the way to the equator, resulting in a "Snowball Earth"; the atmosphere of the early Earth is not well understood. Most geologists believe it was composed of nitrogen, carbon dioxide, other inert gases, was lacking in free oxygen. There is, evidence that an oxygen-rich atmosphere existed since the early Archean. At present, it is still believed that molecular oxygen was not a significant fraction of Earth's atmosphere until after photosynthetic life forms evolved and began to produce it in large quantities as a byproduct of their metabolism.
This radical shift from a chemically inert to an oxidizing atmosphere caused an ecological crisis, sometimes called the oxygen catastrophe. At first, oxygen would have combined with other elements in Earth's crust iron, removing it from the atmosphere. After the supply of oxidizable surfaces ran out, oxygen would have begun to accumulate in the atmosphere, the modern high-oxygen atmosphere would have developed. Evidence for this lies in older rocks that contain massive banded iron formations that were laid down as iron oxides. A terminology has evolved covering the early years of the Earth's existence, as radiometric dating has allowed real dates to be assigned to specific formations and features; the Precambrian is divided into
The Carboniferous is a geologic period and system that spans 60 million years from the end of the Devonian Period 358.9 million years ago, to the beginning of the Permian Period, 298.9 Mya. The name Carboniferous means "coal-bearing" and derives from the Latin words carbō and ferō, was coined by geologists William Conybeare and William Phillips in 1822. Based on a study of the British rock succession, it was the first of the modern'system' names to be employed, reflects the fact that many coal beds were formed globally during that time; the Carboniferous is treated in North America as two geological periods, the earlier Mississippian and the Pennsylvanian. Terrestrial animal life was well established by the Carboniferous period. Amphibians were the dominant land vertebrates, of which one branch would evolve into amniotes, the first terrestrial vertebrates. Arthropods were very common, many were much larger than those of today. Vast swaths of forest covered the land, which would be laid down and become the coal beds characteristic of the Carboniferous stratigraphy evident today.
The atmospheric content of oxygen reached its highest levels in geological history during the period, 35% compared with 21% today, allowing terrestrial invertebrates to evolve to great size. The half of the period experienced glaciations, low sea level, mountain building as the continents collided to form Pangaea. A minor marine and terrestrial extinction event, the Carboniferous rainforest collapse, occurred at the end of the period, caused by climate change. In the United States the Carboniferous is broken into Mississippian and Pennsylvanian subperiods; the Mississippian is about twice as long as the Pennsylvanian, but due to the large thickness of coal-bearing deposits with Pennsylvanian ages in Europe and North America, the two subperiods were long thought to have been more or less equal in duration. In Europe the Lower Carboniferous sub-system is known as the Dinantian, comprising the Tournaisian and Visean Series, dated at 362.5-332.9 Ma, the Upper Carboniferous sub-system is known as the Silesian, comprising the Namurian and Stephanian Series, dated at 332.9-298.9 Ma.
The Silesian is contemporaneous with the late Mississippian Serpukhovian plus the Pennsylvanian. In Britain the Dinantian is traditionally known as the Carboniferous Limestone, the Namurian as the Millstone Grit, the Westphalian as the Coal Measures and Pennant Sandstone; the International Commission on Stratigraphy faunal stages from youngest to oldest, together with some of their regional subdivisions, are: A global drop in sea level at the end of the Devonian reversed early in the Carboniferous. There was a drop in south polar temperatures; these conditions had little effect in the deep tropics, where lush swamps to become coal, flourished to within 30 degrees of the northernmost glaciers. Mid-Carboniferous, a drop in sea level precipitated a major marine extinction, one that hit crinoids and ammonites hard; this sea level drop and the associated unconformity in North America separate the Mississippian subperiod from the Pennsylvanian subperiod. This happened about 323 million years ago, at the onset of the Permo-Carboniferous Glaciation.
The Carboniferous was a time of active mountain-building as the supercontinent Pangaea came together. The southern continents remained tied together in the supercontinent Gondwana, which collided with North America–Europe along the present line of eastern North America; this continental collision resulted in the Hercynian orogeny in Europe, the Alleghenian orogeny in North America. In the same time frame, much of present eastern Eurasian plate welded itself to Europe along the line of the Ural Mountains. Most of the Mesozoic supercontinent of Pangea was now assembled, although North China, South China continents were still separated from Laurasia; the Late Carboniferous Pangaea was shaped like an "O." There were two major oceans in the Carboniferous—Panthalassa and Paleo-Tethys, inside the "O" in the Carboniferous Pangaea. Other minor oceans were shrinking and closed - Rheic Ocean, the small, shallow Ural Ocean and Proto-Tethys Ocean. Average global temperatures in the Early Carboniferous Period were high: 20 °C.
However, cooling during the Middle Carboniferous reduced average global temperatures to about 12 °C. Lack of growth rings of fossilized trees suggest a lack of seasons of a tropical climate. Glaciations in Gondwana, triggered by Gondwana's southward movement, continued into the Permian and because of the lack of clear markers and breaks, the deposits of this glacial period are referred to as Permo-Carboniferous in age; the cooling and drying of the climate led to the Carboniferous Rainforest Collapse during the late Carboniferous. Tropical rainforests fragmented and were devastated by climate change. Carboniferous rocks in Europe and eastern North America consist of a repeated sequence of limestone, sandstone and coal beds. In North America, the early Carboniferous is marine
Mammals are vertebrate animals constituting the class Mammalia, characterized by the presence of mammary glands which in females produce milk for feeding their young, a neocortex, fur or hair, three middle ear bones. These characteristics distinguish them from reptiles and birds, from which they diverged in the late Triassic, 201–227 million years ago. There are around 5,450 species of mammals; the largest orders are the rodents and Soricomorpha. The next three are the Primates, the Cetartiodactyla, the Carnivora. In cladistics, which reflect evolution, mammals are classified as endothermic amniotes, they are the only living Synapsida. The early synapsid mammalian ancestors were sphenacodont pelycosaurs, a group that produced the non-mammalian Dimetrodon. At the end of the Carboniferous period around 300 million years ago, this group diverged from the sauropsid line that led to today's reptiles and birds; the line following the stem group Sphenacodontia split off several diverse groups of non-mammalian synapsids—sometimes referred to as mammal-like reptiles—before giving rise to the proto-mammals in the early Mesozoic era.
The modern mammalian orders arose in the Paleogene and Neogene periods of the Cenozoic era, after the extinction of non-avian dinosaurs, have been among the dominant terrestrial animal groups from 66 million years ago to the present. The basic body type is quadruped, most mammals use their four extremities for terrestrial locomotion. Mammals range in size from the 30–40 mm bumblebee bat to the 30-meter blue whale—the largest animal on the planet. Maximum lifespan varies from two years for the shrew to 211 years for the bowhead whale. All modern mammals give birth to live young, except the five species of monotremes, which are egg-laying mammals; the most species-rich group of mammals, the cohort called placentals, have a placenta, which enables the feeding of the fetus during gestation. Most mammals are intelligent, with some possessing large brains, self-awareness, tool use. Mammals can communicate and vocalize in several different ways, including the production of ultrasound, scent-marking, alarm signals and echolocation.
Mammals can organize themselves into fission-fusion societies and hierarchies—but can be solitary and territorial. Most mammals are polygynous. Domestication of many types of mammals by humans played a major role in the Neolithic revolution, resulted in farming replacing hunting and gathering as the primary source of food for humans; this led to a major restructuring of human societies from nomadic to sedentary, with more co-operation among larger and larger groups, the development of the first civilizations. Domesticated mammals provided, continue to provide, power for transport and agriculture, as well as food and leather. Mammals are hunted and raced for sport, are used as model organisms in science. Mammals have been depicted in art since Palaeolithic times, appear in literature, film and religion. Decline in numbers and extinction of many mammals is driven by human poaching and habitat destruction deforestation. Mammal classification has been through several iterations since Carl Linnaeus defined the class.
No classification system is universally accepted. George Gaylord Simpson's "Principles of Classification and a Classification of Mammals" provides systematics of mammal origins and relationships that were universally taught until the end of the 20th century. Since Simpson's classification, the paleontological record has been recalibrated, the intervening years have seen much debate and progress concerning the theoretical underpinnings of systematization itself through the new concept of cladistics. Though field work made Simpson's classification outdated, it remains the closest thing to an official classification of mammals. Most mammals, including the six most species-rich orders, belong to the placental group; the three largest orders in numbers of species are Rodentia: mice, porcupines, beavers and other gnawing mammals. The next three biggest orders, depending on the biological classification scheme used, are the Primates including the apes and lemurs. According to Mammal Species of the World, 5,416 species were identified in 2006.
These were grouped into 153 families and 29 orders. In 2008, the International Union for Conservation of Nature completed a five-year Global Mammal Assessment for its IUCN Red List, which counted 5,488 species. According to a research published in the Journal of Mammalogy in 2018, the number of recognized mammal species is 6,495 species included 96 extinct; the word "mammal" is modern, from the scientific name Mammalia coined by Carl Linnaeus in 1758, derived from the Latin mamma. In an influential 1988 paper, Timothy Rowe defined Mammalia phylogenetically as the crown group of mammals, the clade consisting of the most recent common ancestor of living monotremes and therian m
The Jurassic period was a geologic period and system that spanned 56 million years from the end of the Triassic Period 201.3 million years ago to the beginning of the Cretaceous Period 145 Mya. The Jurassic constitutes the middle period of the Mesozoic Era known as the Age of Reptiles; the start of the period was marked by the major Triassic–Jurassic extinction event. Two other extinction events occurred during the period: the Pliensbachian-Toarcian extinction in the Early Jurassic, the Tithonian event at the end; the Jurassic period is divided into three epochs: Early and Late. In stratigraphy, the Jurassic is divided into the Lower Jurassic, Middle Jurassic, Upper Jurassic series of rock formations; the Jurassic is named after the Jura Mountains within the European Alps, where limestone strata from the period were first identified. By the beginning of the Jurassic, the supercontinent Pangaea had begun rifting into two landmasses: Laurasia to the north, Gondwana to the south; this created more coastlines and shifted the continental climate from dry to humid, many of the arid deserts of the Triassic were replaced by lush rainforests.
On land, the fauna transitioned from the Triassic fauna, dominated by both dinosauromorph and crocodylomorph archosaurs, to one dominated by dinosaurs alone. The first birds appeared during the Jurassic, having evolved from a branch of theropod dinosaurs. Other major events include the appearance of the earliest lizards, the evolution of therian mammals, including primitive placentals. Crocodilians made the transition from a terrestrial to an aquatic mode of life; the oceans were inhabited by marine reptiles such as ichthyosaurs and plesiosaurs, while pterosaurs were the dominant flying vertebrates. The chronostratigraphic term "Jurassic" is directly linked to the Jura Mountains, a mountain range following the course of the France–Switzerland border. During a tour of the region in 1795, Alexander von Humboldt recognized the limestone dominated mountain range of the Jura Mountains as a separate formation that had not been included in the established stratigraphic system defined by Abraham Gottlob Werner, he named it "Jura-Kalkstein" in 1799.
The name "Jura" is derived from the Celtic root *jor via Gaulish *iuris "wooded mountain", borrowed into Latin as a place name, evolved into Juria and Jura. The Jurassic period is divided into three epochs: Early and Late. In stratigraphy, the Jurassic is divided into the Lower Jurassic, Middle Jurassic, Upper Jurassic series of rock formations known as Lias and Malm in Europe; the separation of the term Jurassic into three sections originated with Leopold von Buch. The faunal stages from youngest to oldest are: During the early Jurassic period, the supercontinent Pangaea broke up into the northern supercontinent Laurasia and the southern supercontinent Gondwana; the Jurassic North Atlantic Ocean was narrow, while the South Atlantic did not open until the following Cretaceous period, when Gondwana itself rifted apart. The Tethys Sea closed, the Neotethys basin appeared. Climates were warm, with no evidence of a glacier having appeared; as in the Triassic, there was no land over either pole, no extensive ice caps existed.
The Jurassic geological record is good in western Europe, where extensive marine sequences indicate a time when much of that future landmass was submerged under shallow tropical seas. In contrast, the North American Jurassic record is the poorest of the Mesozoic, with few outcrops at the surface. Though the epicontinental Sundance Sea left marine deposits in parts of the northern plains of the United States and Canada during the late Jurassic, most exposed sediments from this period are continental, such as the alluvial deposits of the Morrison Formation; the Jurassic was a time of calcite sea geochemistry in which low-magnesium calcite was the primary inorganic marine precipitate of calcium carbonate. Carbonate hardgrounds were thus common, along with calcitic ooids, calcitic cements, invertebrate faunas with dominantly calcitic skeletons; the first of several massive batholiths were emplaced in the northern American cordillera beginning in the mid-Jurassic, marking the Nevadan orogeny. Important Jurassic exposures are found in Russia, South America, Japan and the United Kingdom.
In Africa, Early Jurassic strata are distributed in a similar fashion to Late Triassic beds, with more common outcrops in the south and less common fossil beds which are predominated by tracks to the north. As the Jurassic proceeded and more iconic groups of dinosaurs like sauropods and ornithopods proliferated in Africa. Middle Jurassic strata are neither well studied in Africa. Late Jurassic strata are poorly represented apart from the spectacular Tendaguru fauna in Tanzania; the Late Jurassic life of Tendaguru is similar to that found in western North America's Morrison Formation. During the Jurassic period, the primary vertebrates living in the sea were marine reptiles; the latter include ichthyosaurs, which were at the peak of their diversity, plesiosaurs and marine crocodiles of the families Teleosauridae and Metriorhynchidae. Numerous turtles could be found in rivers. In the invertebrate world, several new groups appeared, including rudists (a reef-formi
The Oligocene is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present. 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 uncertain; the name Oligocene was coined in 1854 by the German paleontologist Heinrich Ernst Beyrich. The Oligocene is followed by the Miocene Epoch; the Oligocene is the final epoch of the Paleogene Period. The Oligocene is 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, a regression of tropical broad leaf forests to the equatorial belt; the start of the Oligocene is marked by a notable extinction event called the Grande Coupure. By contrast, the Oligocene–Miocene boundary is not set at an identified worldwide event but rather at regional boundaries between the warmer late Oligocene and the cooler Miocene.
Oligocene faunal stages from youngest to oldest are: The Paleogene Period general temperature decline is interrupted by an Oligocene 7-million-year stepwise climate change. A deeper 8.2 °C, 400,000-year temperature depression leads the 2 °C, seven-million-year stepwise climate change 33.5 Ma. The stepwise climate change began 32.5 Ma and lasted through to 25.5 Ma, as depicted in the PaleoTemps chart. The Oligocene climate change was a global increase in ice volume and a 55 m decrease in sea level with a related temperature depression; the 7-million-year depression abruptly terminated within 1–2 million years of the La Garita Caldera eruption at 28–26 Ma. A deep 400,000-year glaciated Oligocene Miocene boundary event is recorded at McMurdo Sound and King George Island. During this epoch, the continents continued to drift toward their present positions. Antarctica became more isolated and developed an ice cap. Mountain building in western North America continued, the Alps started to rise in Europe as the African plate continued to push north into the Eurasian plate, isolating the remnants of the Tethys Sea.
A brief marine incursion marks the early Oligocene in Europe. Marine fossils from the Oligocene are rare in North America. There appears to have been a land bridge in the early Oligocene between North America and Europe, since the faunas of the two regions are similar. Sometime during the Oligocene, South America was detached from Antarctica and drifted north towards North America, it allowed the Antarctic Circumpolar Current to flow cooling the Antarctic continent. Angiosperms continued their expansion throughout the world as tropical and sub-tropical forests were replaced by temperate deciduous forests. Open plains and deserts became more common and grasses expanded from their water-bank habitat in the Eocene moving out into open tracts; however at the end of the period, grass was not quite common enough for modern savannas. In North America, subtropical species dominated with cashews and lychee trees present, temperate trees such as roses and pines were common; the legumes spread, while sedges and ferns continued their ascent.
More open landscapes allowed animals to grow to larger sizes than they had earlier in the Paleocene epoch 30 million years earlier. Marine faunas became modern, as did terrestrial vertebrate fauna on the northern continents; this was more as a result of older forms dying out than as a result of more modern forms evolving. Many groups, such as equids, rhinos and camelids, became more able to run during this time, adapting to the plains that were spreading as the Eocene rainforests receded; the first felid, originated in Asia during the late Oligocene and spread to Europe. South America was isolated from the other continents and evolved a quite distinct fauna during the Oligocene; the South American continent became home to strange animals such as pyrotheres and astrapotheres, as well as litopterns and notoungulates. Sebecosuchians, terror birds, carnivorous metatheres, like the borhyaenids remained the dominant predators. Brontotheres died out in the Earliest Oligocene, creodonts died out outside Africa and the Middle East at the end of the period.
Multituberculates, an ancient lineage of primitive mammals that originated back in the Jurassic became extinct in the Oligocene, aside from the gondwanatheres. The Oligocene was home to a wide variety of strange mammals. A good example of this would be the White River Fauna of central North America, which were a semiarid prairie home to many different types of endemic mammals, including entelodonts like Archaeotherium, running rhinoceratoids, three-toed equids, nimravids and early canids like Hesperocyon. Merycoidodonts, an endemic American group, were diverse during this time. In Asia during the Oligocene, a group of running rhinoceratoids gave rise to the indricotheres, like Paraceratherium, which were the largest land mammals to walk the Earth; the marine animals of Oligocene oceans resembled today's fauna, such as the bivalves. Calcareous cirratulids appeared in the Oligocene; the fossil record of marine mammals is a little spotty during this time, not as well known as the Eocene o