|
Post by Gorilla king on Aug 28, 2021 14:32:36 GMT -5
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]
Description
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] Brian Switek 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]
Discovery
Kolponomos clallamensis is known from the Miocene of Slip Point Lighthouse, Washington (48.3°N 124.2°W, paleocoordinates 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]
en.m.wikipedia.org/wiki/Kolponomos
|
|
|
Post by Gorilla king on Aug 28, 2021 14:36:21 GMT -5
PREHISTORIC FAUNA
Kolponomos (Kolponomos Stirton, 1960)
Order: Carnivora
Family: Ursidae
Dimensions: length - 1,2 m, height - 70 сm, weight - 80 kg
Temporal range: Early Miocene of North America (~23 – 20,6 Ma years ago)
A typical representative: Kolponomos clallamensis Stirton, 1960
Kolponomos is an extinct genus of marine bears which existed from the Hemingfordian age to the Aquitanian age of the Miocene epoch, about 20 million years ago. It was described in 1960 by Ruben A. Stirton, a paleontologist at the American Museum of Natural History, from a partial skull and jaw found on the Olympic Peninsula. Stirton thought the fossil was a large marine procyonid, but a specimen found in two pieces by fossil collector Douglas Emlong near Newport, Oregon, in 1969 and 1977, proved the genus was related to ancestors of bears. Since that time, one other Kolponomos fossil has been discovered, in the Aleutian Islands, bringing the total number of specimens to three.
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 been able to view objects directly in front of their heads. 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 unrelated sea otter. Due to the lack of a complete skeleton, however, it is difficult to make inferences about this group's other adaptations.
prehistoric-fauna.com/Kolponomos-clallamensis
|
|
|
Post by Gorilla king on Aug 29, 2021 9:45:30 GMT -5
A unique feeding strategy of the extinct marine mammal Kolponomos: convergence on sabretooths and sea otters
Abstract
Mammalian molluscivores feed mainly by shell-crushing or suction-feeding. The extinct marine arctoid, Kolponomos, has been interpreted as an otter-like shell-crusher based on similar dentitions. However, neither the masticatory biomechanics of the shell-crushing adaptation nor the way Kolponomos may have captured hard-shelled prey have been tested. Based on mandibular symphyseal morphology shared by Kolponomos and sabre-toothed carnivores, we hypothesize a sabretooth-like mechanism for Kolponomos prey-capture, whereby the mandible functioned as an anchor. Torque generated from jaw closure and head flexion was used to dislodge prey by prying, with prey then crushed using cheek teeth. We test this hypothesized feeding sequence using phylogenetically informed biomechanical simulations and shape analyses, and find a strongly supported, shared high mandibular stiffness in simulated prey-capture bites and mandibular shape in Kolponomos and the sabre-toothed cat Smilodon. These two distantly related taxa converged on using mandibles to anchor cranial torqueing forces when prying substrate-bound prey in the former and sabre-driving forces during prey-killing in the latter. Simulated prey-crushing bites indicate that Kolponomos and sea otters exhibit alternative structural stiffness-bite efficiency combinations in mandibular biomechanical adaptation for shell-crushing. This unique feeding system of Kolponomos exemplifies a mosaic of form-function convergence relative to other Carnivora.
www.researchgate.net/publication/296644806_A_unique_feeding_strategy_of_the_extinct_marine_mammal_Kolponomos_convergence_on_sabretooths_and_sea_otters
|
|
|
Post by Gorilla king on Aug 29, 2021 9:52:41 GMT -5
Extinct otter-like 'marine bear' might have had a bite like a saber-toothed cat
Biomechanical modeling suggests that Kolponomos likely used anchor-biting to pry hard-shelled invertebratesDate:New research suggests that the feeding strategy of Kolponomos, an enigmatic shell-crushing marine predator that lived about 20 million years ago, was strangely similar to a very different kind of carnivore: the saber-toothed cat Smilodon. Scientists have shown that even though the two extinct predators likely contrasted greatly in food preference and environment, they shared similar engineering in jaw structure.
FULL STORY
New research suggests that the feeding strategy of Kolponomos, an enigmatic shell-crushing marine predator that lived about 20 million years ago, was strangely similar to a very different kind of carnivore: the saber-toothed cat Smilodon. Scientists at the American Museum of Natural History used high-resolution x-ray imaging and computerized biting simulations to show that even though the two extinct predators likely contrasted greatly in food preference and environment, they shared similar engineering in jaw structure, suitable for anchoring against prey with the lower jaw and forcefully throwing the skull forward to pry loose its food. The study is published today in the journal Proceedings of the Royal Society B.
The only known specimens of Kolponomos--primarily skulls and teeth of two species--were recovered from ancient marine deposits along the Pacific coast of Oregon, Washington, and possibly Alaska. Because of its peculiar morphology and the small number of fossils, the animal's place in the evolutionary tree remains a mystery.
"When Kolponomos was first described in the 1960s, it was thought to be a raccoon relative," said Camille Grohé, a National Science Foundation and Frick Postdoctoral Fellow in the American Museum of Natural History's Division of Paleontology and a co-author on the new paper. "But later research on the skull base led some to think it might be a seal or a bear relative instead, and studies of its teeth show that they are very similar in both shape and wear to the teeth in sea otters."
Sea otters pry their prey--hard-shelled marine invertebrates like clams and mussels--off of surfaces using their hands and rock tools, then crush the shells with their teeth or against their chests, again using tools. By studying Kolponomos fossil material from the National Museum of Natural History in Washington, D.C., and comparative specimens from the American Museum of Natural History, the research team originally set out to test if the extinct predator used otter-like shell-crushing to eat. But the scope of the research expanded after Grohé's collaborator Z. Jack Tseng noticed something curious in parallel to work he was conducting on the saber-toothed cat Smilodon.
"I started seeing a great deal of similarity between the jaws of Kolponomos and Smilodon," said Tseng, a National Science Foundation and Frick Postdoctoral Fellow in the American Museum of Natural History's Division of Paleontology and the lead author on the new paper. "Both of them have a distinctive profile with a deep jaw bone that tapers off toward the back, and both have an expansion of the mastoid processes and the skull's back surface, suggesting large attachment sites for muscles that let the animal move its head powerfully but with control. We definitely didn't expect to bring Smilodon into this study of feeding in a clam-eating marine carnivore, but that's what we ended up doing."
At the Museum's Microscopy and Imaging Facility, the researchers used computed tomography (CT) to scan the skulls of Kolponomos and six other carnivores: Smilodon, grey wolf, sea otter, river otter, brown bear, and leopard. They then used computerized methods to build sophisticated biomechanical models to look at how efficiently the animals could perform various bites, including the jaw-anchored killing shear-bite that is characteristic of saber-tooth cats.
They found that the jaw mechanics of Kolponomos and Smilodon are more similar to each other than to any of the other animals in the study, pointing to a unique feeding strategy in addition to the previous idea that Kolponomos might have crushed its prey like sea otters do today. Taken together, the researchers suggest that Kolponomos might have pried prey off of rocks with its lower jaw, swung its skull forward to dislodge it, and then crunched it with its chewing teeth.
"Our biomechanical data show that the chewing bites of sea otters and Kolponomos are not very similar," Tseng said. "They probably still have an overlapping diet based on tooth wear, but their evolutionary solutions for getting to those hard-shelled animals are dramatically different."
The researchers stress that this finding does not imply shared ancestry between Kolponomos and Smilodon, but rather an intriguing case of convergence--the independent evolution of similar traits.
"This innovative study, showing unexpected feeding similarities between such wildly distinct carnivores, could only happen by applying new technologies to understand specimens from some of the world's greatest archives of ancient life," said John J. Flynn, a curator in the Museum's Division of Paleontology and Dean of the Richard Gilder Graduate School, also an author on this paper.
This work was funded by the U.S. National Science Foundation grant # DEB-1257572 and the American Museum of Natural History's Frick Postdoctoral Fellowships.
The authors have dedicated this study to the memory of Museum artist Chester Tarka, who illustrated Kolponomos newportensis.
www.sciencedaily.com/releases/2016/03/160301211334.htm
|
|
|
Post by Gorilla king on Aug 29, 2021 9:59:38 GMT -5
The prehistoric 'otter' with a formidable bite: Kolponomos was as large as a bear with jaws like a sabre-toothed cat
Kolponomos lived 20 million years ago on the north west coast of the US
It is only known from a handful of fossils discovered during the 1960s
Scientists thought it may have eaten much like modern-day sea otters
But new research has shown they had jaws similar to sabre-toothed cats
Researchers used CT scans and computer modelling to analyse the jaws of Kolponomos and found surprising similarities with the extinct big cat Smilodon, which had long sabre-like teeth. While Kolponomos did not have these long teeth, it is thought it used a similar eating technique when devouring shellfish
www.dailymail.co.uk/sciencetech/article-3472775/Prehistoric-otter-formidable-bite-Kolponomos-size-bear-jaws-like-sabre-toothed-cat-don-t-worry-snacked-shellfish.html
|
|
|
Post by oldindigosilverback on Sept 12, 2021 2:53:55 GMT -5
They might only eat shellfish but that does not make them weak.
|
|
|
Post by Gorilla king on Jan 27, 2023 17:22:41 GMT -5
One among many: the enigmatic case of the Miocene mammal, Kolponomos newportensis
Abstract
Kolponomos newportensis is an enigmatic Miocene mammal allied to stem Pinnipedimorpha. It has been suggested that Kolponomos fed on hard-shelled benthic marine invertebrates by using its mandible as a wedge to dislodge its prey from the sea bottom by means of strong pull and torque forces. This unique feeding style was thought to originate from a singular case of mosaic convergence in mandible biomechanics between Kolponomos and the sabretoothed cat Smilodon, which complied with similarly strong torque forces when grappling with prey. As such forces must have reflected on the cranium as well, we hypothesize that the convergence between Kolponomos and the sabretoothed cats could have affected its shape. To test this hypothesis, we looked for patterns of morphological convergence in cranial shape between Kolponomos and sabretoothed cats. We found that Kolponomos is not distinctly closer to Smilodon than a number of other pinnipeds. Yet, local areas of shape convergence with Smilodon are observed in the canine area and the posterior part of the cranium, that is where the bite applies and the temporalis muscle is located, respectively. These results indicate that the mosaic convergence present between the mandibles of Kolponomos and Smilodon is partially reflected in the cranium as well.
www.researchgate.net/publication/363054588_One_among_many_the_enigmatic_case_of_the_Miocene_mammal_Kolponomos_newportensis
|
|