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Post by arctozilla on Jul 5, 2022 4:03:04 GMT -5
Ammitocyon kainos gen. et sp. nov., a chimerical amphicyonid (Mammalia, Carnivora) from the late Miocene carnivore traps of Cerro de los Batallones (Madrid, Spain) Abstract In the present paper, we describe the craniodental remains of three individuals of an amphicyonid previously determined as Thaumastocyon sp. from the late Miocene (c. 9.1 Ma) pseudokarstic site of Batallones-3. Dentognathic differences in relation to other Thaumastocyoninae enable a new taxon, Ammitocyon kainos gen. et sp. nov., to be defined; it is both the most recent and the most complete member of this subfamily known in the fossil record. The results of our phylogenetic analysis demonstrate that this new form reached the maximum degree of specialization within Thaumastocyoninae, a group that includes the most hypercarnivorous amphicyonid species of the Miocene. The masticatory apparatus of A. kainos is extremely derived, with the loss of the mesial premolars (P3 / P2 and p1–p3) and the third molars (M3 / m3). The robustness of the chin and muzzle is in contrast with the slender and highly sectorial postcanine dentition (p4 / m2 and P4 / M2), features that are consistent with the values provided by an analysis of the bending resistance of the mandible performed for these specimens. All the anatomical features combined, both cranial and postcranial, reveal the complexity of the body plan of A. kainos. This species combines a derived hypercarnivorous dentition with one of the most robust postcranial skeletons recorded for all large caniform carnivorans, outlining an enigmatic taxon that possesses unique ecological adaptations. www.tandfonline.com/doi/full/10.1080/14772019.2021.1910868
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Post by arctozilla on Jul 5, 2022 14:07:46 GMT -5
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Post by arctozilla on Jul 5, 2022 14:26:22 GMT -5
A new amphicyonid (Mammalia, Carnivora, Amphicyonidae) from the late middle Miocene of northern Thailand and a review of the amphicyonine record in Asia Recent field research conducted in the middle Miocene basin of Mae Moh, northern Thailand, allow discovering dental remains of a new amphicyonid (Mammalia, Carnivora, Amphicyonidae). A thorough comparison with all known Asian and non-Asian Miocene genera of Amphicyonidae supports the assignment of these specimens to a new amphicyonine, Maemohcyon potisati gen. et sp. nov. We propose the first review of the fossil record of the Amphicyoninae and we discuss the possible geographic origin and phylogenetic relationships of this new taxon. It appears that Maemohcyon does not have close relationships with contemporary ( Amphicyon, Pseudocyon, Ischyrocyon, Pliocyon) or earlier ( Ictiocyon, Pseudarctos, Cynelos, Ysengrinia) genera. We suggest that the Maemohcyon lineage probably arrived much earlier than 13 Ma (age of Mae Moh fauna) and evolved in this insulated region until the late middle Miocene. ui.adsabs.harvard.edu/abs/2006JAESc..26..519P/abstract
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Post by arctozilla on Jul 9, 2022 9:05:51 GMT -5
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Post by arctozilla on Jul 9, 2022 12:29:20 GMT -5
Long-legged pursuit carnivorans (Amphicyonidae, Daphoeninae) from the early Miocene of North America. (Bulletin of the American Museum of Natural History, no. 318) Abstract: In the early Miocene, endemic North American amphicyonids of the subfamily Daphoeninae evolved a lineage of large beardogs adapted for prey pursuit over open terrain. Three species comprise this lineage, here placed in the genus Daphoenodon, subgenus Borocyon Peterson, 1910, the sister subgenus to the daphoenine beardog Daphoenodon (Daphoenodon). These species (Borocyon robustum, B. niobrarensis, B. neomexicanus, n. sp.) are distinguished by limbs modified for fore-aft motion and parasagittal alignment contributing to a lengthened stride. These adaptive features are most evident in the terminal species, B. robustum, where the forelimb is conspicuously elongated. The species of Borocyon increase in body size from small B. neomexicanus, known only from the latest Arikareean of northern New Mexico, through earliest Hemingfordian B. niobrarensis from western Nebraska and southeast Wyoming, to B. robustum, likely the keystone predator of its guild. Borocyon robustum (~ 100-150 kg) was the most widely distributed, occurring during the early Hemingfordian from the Pacific Northwest through the Great Plains to the Florida Gulf Coast. Regional aridity prevalent in the North American midcontinent during the Arikareean may have contributed to the emergence of Borocyon by providing an appropriate niche for a long-legged, open-country predator. The skeleton of Borocyon robustum, based on composite elements acquired over many decades, reveals a carnivoran unlike any living pursuit predator. The species displays a mosaic of postcranial features that parallel limb elements of both highly evolved cursors (Canis lupus, Acinonyx jubatus) and large, ambush felids (Panthera leo, P. tigris). Skeletal traits contributing to its efficient locomotion include: proportionately lengthened forelimbs, the parasagittal radioulnar articulation with the humerus, an elongate radius and ulna, a modified carpal structure, and paraxonic elongate metapodials of the fore- and hindfoot, as well as details of the anatomy of femur, tibia, and proximal tarsals. These postcranial features indicate a large digitigrade predator with a number of anatomical parallels in the forelimb to running pursuit predators such as the wolf, but there are also musculoskeletal adaptations of the shoulder and hindlimb that compare with those of large, living felids. Skull, dentition, and mandibular anatomy are similar to those of living wolves. However, Borocyon robustum, on average a much larger carnivore, placed even greater emphasis on a pattern of dental occlusion and toothwear suggesting both carnivory and durophagous habits. Physiological attributes of Borocyon that may have contributed significantly to its adaptive program as a pursuit predator remain unknown. digitallibrary.amnh.org/handle/2246/5948
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Post by arctozilla on Jul 11, 2022 7:20:34 GMT -5
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Post by arctozilla on Jul 11, 2022 8:09:38 GMT -5
The apex of amphicyonid hypercarnivory: solving the riddle of Agnotherium antiquum Kaup, 1833 (Mammalia, Carnivora) ABSTRACT Since its first description, only a single undisputed specimen, an isolated, highly abraded m1, was known from the enigmatic amphicyonid Agnotherium antiquum Kaup, 1833. Here, we describe the second specimen of A. antiquum from the type locality of Eppelsheim (early late Miocene, MN 9/10 of Germany), unearthed 184 years after the first description of A. antiquum. The specimen consists of a partial left juvenile mandible with dp3, m1 in eruption, i3, canine, p4, and a highly reduced m2 still in crypt. The p1–3 and m3 are completely reduced, as are the metaconids of m1 and m2. We confirm previous assignments of late Miocene specimens from the localities of Charmoille, Switzerland, and Pedregueras 2A, Spain, to A. antiquum, whereas a maxilla from Bled Douarah, Tunisia, can only tentatively be assigned to the species. We confirm that the monotypic genus Agnotherium is a thaumastocyonine amphicyonid, discuss other supposed thaumastocyonine specimens, and briefly review the evolutionary history of the subfamily. Agnotherium was a 275 kg, extremely powerful, strictly carnivorous ambush hunter that represents the apex of amphicyonid evolution toward carnivory. Its tooth eruption pattern resembles recent Ursus more than recent Canis, but it shows a considerable delay of eruption timing like in the ursid Agriotherium. Agnotherium antiquum is one of six carnivoran species from the Eppelsheim Formation that is heavier than 200 kg. The co-occurrence of Agnotherium (or its relatives Tomocyon and Thaumastocyon), Machairodus, and a smaller saber-toothed carnivoran is typical for early late Miocene faunas of Europe and tentatively North Africa. www.tandfonline.com/doi/full/10.1080/02724634.2019.1705848
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Post by Gorilla king on Jul 11, 2022 9:17:48 GMT -5
New material of Amphicyon zhanxiangi from laogou, linxia basin suggests a possible southern dispersal with increasing omnivory
Abstract
The fossil records of large amphicyonids in Asia are rare and fragmentary, and their evolution and dispersal are also unclear. Here we present new dental material from Laogou, Linxia Basin, Gansu Province, belonging to the Hujialiang Formation, Middle Miocene. The new material is very similar to Amphicyon zhanxiangi from the Dingjia’ergou fauna of the Zhang’enbao Formation, Tongxin, Ningxia, and can be referred to this species. It is younger than the Tongxin material and differs from the latter by having better-distinguished cusps in upper molars, supporting this species is probably the ancestor to the omnivorous Arctamphicyon found in the Siwaliks, Yuanmou, and the Lower Irrawaddy. This lineage might immigrate to southern and southeastern Asia by the Late Miocene, and adapted to an increasing omnivorous diet due to more available plant material in tropical and subtropical regions.
www.researchgate.net/publication/353099418_New_material_of_Amphicyon_zhanxiangi_from_laogou_linxia_basin_suggests_a_possible_southern_dispersal_with_increasing_omnivory
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Post by Gorilla king on Jul 11, 2022 9:26:52 GMT -5
Ichnological evidence of a Miocene rhinoceros bitten by a bear-dog (amphicyon giganteus): Rhinocéros du miocène mordu par un chien-ours (amphicyon giganteus) : preuves ichnologiques
Abstract
A rhinocerotid hemimandible, the Iberotherium rexmanueli zbyszewskii holotype, was bitten by Amphicyon giganteus, a carnivore that could attack large prey and be an opportunistic scavenger as well. The large, young adult Iberotherium was not senile and may have been killed by a single individual or by a pack of Amphicyon giganteus, but disease or accident may also have caused its death. Alternatively, during a drought event, a dying or in harsh physical condition rhinoceros may have been overcome while seeking a water point where ambush would be possible. Death also may have been a consequence of a major flood. As decay progressed and the remnants were eventually deposited, parts could have been consumed by scavengers. After consumption, wet bone surfaces could undergo some corrosion. Fissures may have resulted from desiccation or mechanical stress. The hemimandible was abandoned after consumption and left exposed until new sands were deposited over it.
Young adult, incomplete left hemimandible with P4-M3, severely bitten by a large carnivore mammal, probably an Amphicyon giganteus. External view. Figures: Rhinocerotidae-Iberotherium rexmanueli zbyszewskii (Antunes and Ginsburg, 1983). Type specimen of the subspecies. Hémimandibule gauche incomplète avec P4-M3 d'un adulte jeune, mordue par un mammifère carnivore de grande taille, probablement par un Amphicyon giganteus. Vue externe. Figures : Rhinocerotidae-Iberotherium rexmanueli zbyszewskii (Antunes et Ginsburg, 1983). Spécimen type de la sousespèce.
External view of cast to show bite marks. Vue externe d'un moulage pour montrer des empreintes des morsures.
www.researchgate.net/publication/40663768_Ichnological_evidence_of_a_Miocene_rhinoceros_bitten_by_a_bear-dog_amphicyon_giganteus_Rhinoceros_du_miocene_mordu_par_un_chien-ours_amphicyon_giganteus_preuves_ichnologiques
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Post by arctozilla on Jul 11, 2022 15:24:28 GMT -5
Diversity of Amphicyonidae (Carnivora, Mammalia) in the Middle Miocene Halamagai formation in Ulungur River area, Xinjiang, Northwestern China ABSTRACT Amphicyonidae is one of the most widely distributed families of Carnivora in the Early and Middle Miocene, yet the fossil record of this family is extremely poor in Eastern Asia. In this study, we report an unanticipated diversity of Amphicyonidae from the Middle Miocene Halamagai Formation in Ulungur River area, Xinjiang, Northwestern China. At least five species of very different size: Amphicyon ulungurensis (including Amphicyon cf. ulungurensis), Gobicyon zhegalloi, Cynelos cf. bohemicus, Cynelos aff. helbingi and cf. Cynelos sp. based on rare teeth and postcranials were found in the Halamagai Formation. Such diversity of amphicyonids from East Asia is previously unrecorded and indicates the probable presence of a representative Mid-Miocene amphicyonid guild. The geographic location of these species supports the existence of a Palaearctic Neogene faunal exchange of amphicyonids between Europe and East Asia during the early Middle Miocene interval. www.tandfonline.com/doi/full/10.1080/08912963.2018.1477142
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Post by arctozilla on Jul 11, 2022 15:52:07 GMT -5
The last amphicyonid (Mammalia, Carnivora) in Africa Amphicyonidae are a common element of carnivoran faunas in the early and middle Miocene of Eurasia and North America, but by the Messinian they had become extinct there, except possibly on the Indian subcontinent. In Africa, amphicyonids are poorly known from a scattering of records from the late Oligocene to the late Miocene. In this paper, we describe the last-surviving amphicyonid in Africa, from Messinian-age sediments (dated c. 6.5-5.3 Ma) of Ethiopia (Gona) and Kenya (Lothagam and possibly Lemudong'o). This new taxon shows unique adaptations to hypercarnivory in the lower molars and was small for an amphicyonid, dentally about the size of a coyote, Canis latrans. © Publications Scientifiques du Muséum national d'Histoire naturelle, Paris. www.researchgate.net/publication/288046433_The_last_amphicyonid_Mammalia_Carnivora_in_Africa
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Post by arctozilla on Jul 11, 2022 18:21:42 GMT -5
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Post by arctozilla on Jul 12, 2022 8:46:44 GMT -5
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Post by arctozilla on Jul 12, 2022 12:08:33 GMT -5
Evolution of Large Carnivores During the Mid-Cenozoic of North America: The Temnocyonine Radiation (Mammalia, Amphicyonidae) Abstract This study describes and summarizes the Temnocyoninae (Mammalia, Carnivora), a subfamily of amphicyonid carnivores of considerable diversity and singular ecomorphology within Cenozoic faunas of North America. In temnocyonines, we see the first carnivorans to occupy an ecological niche as large cursorial predators. The subfamily is confined to the Arikareean NALMA, ranging in age from the latest early Oligocene to the early Miocene. Distributed from the Pacific Northwest to the Great Plains and Florida, there are four genera (Temnocyon, Mammacyon, Delotrochanter n. gen., Rudiocyon n. gen.) and 12 species, of which eight are newly described (Temnocyon subferox, T. fingeruti, T. macrogenys; Rudiocyon amplidens; Mammacyon ferocior; Delotrochanter petersoni, D. oryktes, D. major). Among the specimens examined are eight skulls, three with intact basicranial morphology that establish the presence of a plesiomorphic arctoid auditory region in the subfamily. Temnocyonine dentitions and postcranial skeletons reveal a blend of morphological characteristics not previously nor subsequently seen among the Carnivora. From a stem species, Temnocyon altigenis, there evolve both large hypercarnivorous (Temnocyon) and durophagous forms (Mammacyon, Delotrochanter); these genera share a derived dentition that defines the Temnocyoninae. Delotrochanter oryktes n. sp., an early Miocene species, was found in a den, suggesting a possible burrowing capability and sheltering of offspring. The John Day basin of Oregon and the central Great Plains (western Nebraska, southeast Wyoming) are the source of most temnocyonine fossils; a few have been found in southern California and Florida, indicative of a continent-wide distribution. Temnocyonines have often been confused with canids, however their basicranial anatomy places them securely within the Amphicyonidae. First discovered in the 1870s, only ∼30 individuals comprise the entire record of the subfamily. Many were found in proximity to radioisotopically calibrated tuffs and ignimbrites and/or were closely associated with mammals of established biochronologic age. Thus, most species can be placed in a temporal context. With rare exception, the fossils represent isolated occurrences, hence estimates of variation within a population are lacking. Cursorial postcranial features characterize several lineages (Mammacyon, Delotrochanter) and probably were present in other temnocyonines known only from dental remains. Late Oligocene Mammacyon ferocior and early Miocene Delotrochanter oryktes evolved uniquely configured crushing cheek teeth and cursorial limbs, combining distinctive dental and skeletal traits in a manner not seen in any living carnivore. These species are interpreted as large durophagous predators with craniodental characteristics that parallel living hyaenids (Crocuta crocuta) and postcranial adaptations approaching those of cursorial canids such as the wolf (Canis lupus). Expansion of semiarid grasslands and savanna during the late Oligocene and early Miocene in the central Great Plains seems to have favored the evolution of these wide-ranging. bioone.org/journals/bulletin-of-the-american-museum-of-natural-history/volume-2011/issue-358/358.1/Evolution-of-Large-Carnivores-During-the-Mid-Cenozoic-of-North/10.1206/358.1.short
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Post by arctozilla on Jul 12, 2022 12:37:19 GMT -5
Amphicyon major fighting Daeodon from Blue Rhino Studio.
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Post by Gorilla king on Jul 12, 2022 20:49:14 GMT -5
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Post by arctozilla on Jul 13, 2022 8:30:12 GMT -5
Fossil "Beardogs" Shed Light On Evolution Of Dogs Members of the dog branch today include dogs, wolves, foxes, bears, sea lions, and weasels. Beardogs are from an earlier point in that group’s history, before they branched out into the dog relatives we see today. “They’re equally related to all of the dog relatives alive today—they’re not the direct ancestors of modern wolves and bears, but more like their cousins,” explains Tomiya. www.fieldmuseum.org/blog/fossil-beardogs-shed-light-evolution-dogs
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Post by arctozilla on Jul 15, 2022 8:29:36 GMT -5
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Post by arctozilla on Jul 15, 2022 10:47:10 GMT -5
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Post by arctozilla on Jul 15, 2022 10:59:36 GMT -5
Amphicyon longiramus Quick Facts Ventral view of skull, UF 162723 Common Name: White’s bear-dog The Florida Museum of Natural History has over 550 specimens of this species in its collection, and has the only known mounted skeleton of the species on public display. Amphicyon longiramus was the top carnivore in Florida 16 to 18 million years ago. Some species of bear-dogs evolved wolf-like qualities such as longer legs and tearing-teeth, while others (including White’s bear-dog) evolved more bear-like qualities such as a broader body and slower gait, and crushing molars. Its closest modern ecologic equivalent is the grizzly bear. Age Range Early Miocene Epoch; Hemingfordian land mammal age About 18 to 16 million years ago www.floridamuseum.ufl.edu/florida-vertebrate-fossils/species/amphicyon-longiramus/
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