Kolponomos Temporal range: | |
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Skull | |
Mandible | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Mammalia |
Order: | Carnivora |
Family: | † Amphicynodontidae |
Genus: | † Kolponomos Stirton, 1960 |
Species | |
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Kolponomos is an extinct genus of carnivoran mammal that existed in the Late Arikareean North American Land Mammal Age, early Miocene epoch, about 20 million years ago. It was likely a marine mammal. [1] The genus was erected in 1960 by Ruben A. Stirton, a paleontologist at the University of California Museum of Paleontology, Berkeley, for the species K. clallamensis, on the basis of a partial skull and jaw found on the Olympic Peninsula. At the time, Stirton questionably assigned it to Procyonidae, its systematic position remained problematic until the discovery of more fossils including a nearly complete cranium from the original locality of K. clallamensis which helped identify it as part of the group from which pinnipeds evolved. [2]
In life, species of Kolponomos had downturned snouts and broad, heavy molars that would have been suited to a diet of hard-shelled marine invertebrates, and their narrow snouts and anteriorly directed eyes indicate that they would have had stereoscopic vision. [2] Large neck muscle attachments and robust foot bones combine with these features to suggest that Kolponomos filled a unique niche among marine carnivores, approached today only by the very distantly related sea otter. Due to the lack of a complete skeleton, however, it is difficult to make inferences about this genus' other adaptations.
Based on the skull and jaws known, Kolponomos convergently evolved mandibular and bite features that had similarities to extant bears, sea otters, and even the sabretooth Smilodon. The anterior portion of the jaw becomes a functional anchoring fulcrum in both Kolponomos and Smilodon. Although dental morphology and heavy occlusal wear patterns are shared with the sea otter. Kolponomos' dentition was less efficient but exhibited higher stiffness than in the sea otter. [1] Riley Black wrote that Kolponomos bit like a sabrecat, crunched like a bear. [3]
Aspects of its feeding morphology were similar to the giant otter Siamogale melilutra , although Kolponomos is not an otter [4]
Kolponomos clallamensis is known from the Miocene of Slip Point Lighthouse, Washington ( 48°18′N124°12′W / 48.3°N 124.2°W , paleocoordinates 48°00′N116°54′W / 48.0°N 116.9°W ). [5] [6] [7] The species was originally based on a rostrum found in 1957 at Slip Point in Clallam Bay, Washington. A nearly complete cranium was found at the same location in 1988. Both K. clallamensis and K. newportensis are associated with the late Arikareean NALMA. [8]
Kolponomos newportensis was described in 1994 by R. Tedford, L. Barnes and Clayton E. Ray. It is represented by single specimen: a nearly complete skull, jaw and post-cranial bones found in a concretion of sediment. The concretion was discovered in two pieces by fossil collector Douglas Emlong near Newport, Oregon, the first in 1969 and the second, eight years later, in 1977. Because the concretion had been hardened so much by tectonic stress, the paleontological laboratory at the Smithsonian Institution considered them "the most difficult materials ever encountered by our laboratory.," [9] and a combination of techniques proved essential to its extraction and preparation, which lasted two decades. Discovery of K. newportensis disproved the earlier hypothesis that the genus was related to the ancestors of raccoons, and instead was a stem-pinniped. [2] [10] [11]
Carnivora is an order of placental mammals that have specialized in primarily eating flesh, whose members are formally referred to as carnivorans. The order Carnivora is the sixth largest order of mammals, comprising at least 279 species on every major landmass and in a variety of habitats, ranging from the cold polar regions of Earth to the hyper-arid region of the Sahara Desert and the open seas. Carnivorans exhibit a wide array of body plans, varying greatly in size and shape.
The order Peramelemorphia includes the bandicoots and bilbies. All members of the order are endemic to Australia-New Guinea and most have the characteristic bandicoot shape: a plump, arch-backed body with a long, delicately tapering snout, very large upright ears, relatively long, thin legs, and a thin tail. Their size varies from about 140 grams up to 4 kilograms, but most species are about one kilogram.
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.
A saber-tooth is any member of various extinct groups of predatory therapsids, predominantly carnivoran mammals, that are characterized by long, curved saber-shaped canine teeth which protruded from the mouth when closed. Saber-toothed mammals have been found almost worldwide from the Eocene epoch to the end of the Pleistocene epoch.
Caniformia is a suborder within the order Carnivora consisting of "dog-like" carnivorans. They include dogs, bears, raccoons, and mustelids. The Pinnipedia are also assigned to this group. The center of diversification for the Caniformia is North America and northern Eurasia. Caniformia stands in contrast to the other suborder of Carnivora, the Feliformia, the center of diversification of which was in Africa and southern Asia.
Thylacosmilus is an extinct genus of saber-toothed metatherian mammals that inhabited South America from the Late Miocene to Pliocene epochs. Though Thylacosmilus looks similar to the "saber-toothed cats", it was not a felid, like the well-known North American Smilodon, but a sparassodont, a group closely related to marsupials, and only superficially resembled other saber-toothed mammals due to convergent evolution. A 2005 study found that the bite forces of Thylacosmilus and Smilodon were low, which indicates the killing-techniques of saber-toothed animals differed from those of extant species. Remains of Thylacosmilus have been found primarily in Catamarca, Entre Ríos, and La Pampa Provinces in northern Argentina.
Potamotherium an extinct genus of caniform carnivoran from the Miocene epoch of France and Germany. It has historically been assigned to the family Mustelidae, but more recent studies suggest that it represents a primitive relative of pinnipeds
Desmatophoca is an extinct genus of early pinniped that lived during the Miocene, and is named from the Greek "phoca", meaning seal. A taxon of the family Desmatophocidae, it shares some morphological similarities with modern true seals. Two species are recognized: Desmatophoca oregonensis and Desmatophoca brachycephala. Little information exists regarding Desmatophoca, due to the small number of fossil samples obtained and identified.
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Nothocyon is an extinct genus of carnivoran in the family Subparictidae which inhabited North America during the late Oligocene. At one time, many species of the dog family Canidae were placed in Nothocyon, but new fossils showed that the type species of Nothocyon, N. geismarianus, is more closely related to bears. The other species have been reassigned to other genera such as Cormocyon.
Enhydrocyon is an extinct genus of bone crushing canid which inhabited North America during the Oligocene and Early Miocene, 30.8—20.4 Ma, existing for approximately 11 million years.
Puijila darwini is an extinct species of stem-pinniped (seal) which lived during the Miocene about 21 to 24 million years ago. About a metre long, the animal had only minimal physical adaptations for swimming. Unlike modern pinnipeds, it did not have flippers and its shape was otter-like, albeit more specialized; its skull and teeth are the features that most clearly indicate that it is a seal.
Ysengrinia is an extinct genus of carnivoran in the family Amphicyonidae, that lived during the Late Oligocene to Early Miocene. Fossil remains have been discovered in Western Europe, the United States and possibly China. The European species are among the earliest known members of the Thaumastocyoninae, a group of aberrant amphicyonids showcasing hypercarnivorous adations, but are only known from fragmentary remains. The American species is much better preserved and shows a robust, black-bear sized predator. These fossils play an important role in our understanding of the biotic interchange between Eurasia and North America during the earliest Miocene. However, more recent research suggests that the genus might be polyphyletic, and that several of its species should be excluded from Ysengrinia.
Palaeogale is an extinct genus of carnivorous mammal known from the Late Eocene, Oligocene, and Early Miocene of North America, Europe, and Eastern Asia. A small carnivore often associated with the mustelids, Palaeogale might have been similar to living genets, civets, and linsangs.
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Siamogale melilutra is an extinct species of giant otter from the late Miocene from Yunnan province, China.
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