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Post by arctozilla on Jul 5, 2022 2:58:48 GMT -5
They are an order of extinct mammalian predators who are closely related to the pangolins. They ruled the food chain long before carnivorans.  |
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Post by arctozilla on Jul 5, 2022 3:12:36 GMT -5
The Creodonts Creodonta is an extinct, possibly polyphyletic[3][4][5][6][7][8][9] order of carnivorous mammals that lived from the Paleocene to the Miocene epochs. Because they both possess carnassial teeth, creodonts and carnivorans were once thought to have shared a common ancestor, but given that different teeth are involved in making up the carnassials (both between creodonts and carnivorans and between the main groups of creodonts), this appears to be a case of evolutionary convergence. Carnassials are also known in other mammal clades, such as in the extinct bat Necromantis.  Two distinct families were historically thought to compose the order: Oxyaenidae and Hyaenodontidae. They may both represent separate orders of fossil mammals related to carnivoramorphs or are descended from more basal taxa. Creodonts had an extensive range, both geographically and temporally. They are known from the late Paleocene through the late Oligocene in North America, the early Eocene through late Oligocene in Europe, from the early Eocene through late Miocene in Asia, and from the Paleocene to the late Miocene in Africa.[10] Creodonts were the first large, obviously carnivorous mammals with the radiation of the oxyaenids in the late Paleocene.[11] During the Paleogene, they were the most abundant form of terrestrial carnivore in the Old World.[12] In Oligocene Africa, they were the dominant predatory group. They competed with the Mesonychids and the Entelodonts and ultimately outlasted them by the start of the Oligocene and by the middle of the Miocene respectively, but lost ground to the carnivorans. The last genus became extinct 11.1 million years ago, and carnivorans now occupy their ecological niches. en.wikipedia.org/wiki/Creodonta |
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Post by arctozilla on Jul 5, 2022 3:55:01 GMT -5
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Post by arctozilla on Jul 5, 2022 4:15:50 GMT -5
Brains of early carnivores Abstract It is commonly believed that the brains of the ancestors of modern carnivores (miacids) were superior to (e.g., larger than) those of other early carnivores (creodonts and mesonychids). Examination of the fossil record of brains of early carnivores reveals no evidence to support that belief. Moreover, evolutionary trends towards increasing relative brain size and an expansion of neocortex are seen in both miacids and creodonts. The neocortex expanded in a different way in miacids than in creodonts and mesonychids (evidenced by different sulcal patterns), but the biological significance of the observed differences is unknown. www.cambridge.org/core/journals/paleobiology/article/abs/brains-of-early-carnivores/AE507D4080D40AA8254D1306CC349824 |
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Post by arctozilla on Jul 5, 2022 4:29:40 GMT -5
Creodonta and Carnivora from the Early Miocene of the Northern Sperrgebiet Namibia Abstract Between 1993 and 2007 the Namibia Palaeontology Expedition collected a variety of carnivorous mammals in the Northern Sperrgebiet, comprising six species of Creodonta and the same number of Carnivora. Although carnivoran remains tend to be rare in the Sperrgebiet, some significant discoveries were made including a new genus and three new species. The Sperrgebiet carnivorans range in size from a tiny hypercarnivorous creodont discovered in 2001 at Elisabethfeld, which is the smallest known carnivorous mammal reported from Africa, to gigantic Hyainailouros, the largest known creodont. Several fissipeds belonging to Amphicyonidae, Viverridae and Felidae were collected, but the only ones which are well preserved are two new species of Leptoplesictis. www.researchgate.net/publication/235672779_Creodonta_and_Carnivora_from_the_Early_Miocene_of_the_Northern_Sperrgebiet_Namibia |
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Post by Gorilla king on Jul 5, 2022 6:12:02 GMT -5
A skeleton of a Uintan machaeroidine ‘creodont’ and the phylogeny of carnivorous eutherian mammals
Abstract
An edentulous partial skeleton of a carnivorous mammal from the Uinta Formation (middle Eocene) of Utah is referred to the rare and enigmatic sabre-tooth clade Machaeroidinae primarily on the basis of alveolar patterns and cranial morphology. The newly recognized skeleton includes portions of both girdles, all long bones, and the first known tarsal and phalangeal material of a machaeroidine. The specimen permits a preliminary reconstruction of the locomotor habits of machaeroidines, which appear to have been adapted to scansorial or arboreal rather than terrestrial locomotion. The new material also prompts a review of machaeroidine affinities, which have been unresolved for over a century, with consensus opinion favouring a link to either oxyaenid or limnocyonine hyaenodontid ‘creodonts’. Postcranial evidence favours a link to oxyaenids, as machaeroidines share numerous features with oxyaenids that are lacking in hyaenodontids. To test this relationship machaeroidines were included in a phylogenetic analysis broadly sampling early carnivorous eutherians, including members of both ‘Creodonta’ and Carnivoramorpha. Results place Machaeroidinae within Oxyaenidae but fail to support either ‘creodont’ or carnivoramorphan monophyly. Instead, Oxyaenidae is linked with Carnivoraformes, while Viverravidae is basally positioned among carnivorous eutherians. Reconsideration of the character evidence cited in support of Carnivoramorpha indicates that many features are ambiguous in the context of a broad sample of ‘creodonts’ and early carnivoramorphans. Hyaenodontid monophyly is also not recovered but this likely reflects the influence of one morphologically divergent genus, Arfia.
www.researchgate.net/publication/325204791_A_skeleton_of_a_Uintan_machaeroidine_%27creodont%27_and_the_phylogeny_of_carnivorous_eutherian_mammals
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Post by Gorilla king on Jul 5, 2022 6:15:20 GMT -5
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Post by arctozilla on Jul 5, 2022 14:43:16 GMT -5
Ecomorphology of the European Hyaenodon Hyaenodon was a speciose genus in the late Eocene to early Miocene distributed over the Northern hemisphere (Europe, North America and Asia). Taking into account that carnivorous mammals are not as numerously preserved as others, certain Oligocene sites yield a considerable amount of material. This is true especially for North America (e.g. White River formation). In Europe, Quercy (France) is a complex of fissure fillings bearing a rich fossil record of many taxa including Hyaenodon. Concerning Asia the evidence is sparser and most findings come from Mongolia. The focus of this thesis is on the ecomorphology of the European Hyaenodon with the aim to reconstruct diet, sensory capabilities and the locomotion pattern. However, facts of taxonomic value are discussed as well. Hyaenodon has long been regarded as having been capable of processing bone. The enamel thickness, stereomicrowear results and the ultrastructure of the enamel were used as additional information to dental morphology and wear patterns to reconstruct the diet of this fossil predator. The ossiphagous tendencies can be confirmed. Hyaenodon occupies a broad dietary niche — overlapping with those of the recent lion and the spotted hyena. Different dietary tendencies were observed in the European and the North American taxa. The sense of touch and hearing, as well as the brain were examined in detail. For the first time an auditory ossicle of Hyaenodon is described. The infraorbital foramen is rather small. Hyaenodon did not possess as specialized whiskers as felids do. The sense of touch — concerning the whiskers — was equally developed as in canids. Reviewing the hitherto knowledge of the brain — the following features were apparent: the neocortex is small, but folded; the olfactory lobes are largely developed. The sense of smell was compared to other senses important in Hyaenodon. The hearing apparatus was examined including the bulla, an auditory ossicle (the incus) and the inner ear (cochlea and semicircular canals). The bulla is made up by a chambered entotympanic. The coiling of the cochlea is of the same degree as in dogs. The semicircular canals are extensive. The incus is showing the usual saddle-shaped facet, but with a large upper articulation surface and a small, circular lower articulation facet. Compared to recent carnivores it is most similar to cats. Hyaenodon was not adapted to low frequencies and most probably had a wide frequency range (as predators commonly do) with a possible adaptation to high frequencies (as in cats). The skeletal remains, although by far less frequently preserved in Europe than in North America, were the basis for the inferences of locomotion pattern and predation style. The nuchal ligament was assumed to support the proportionally oversized head (compared to recent Carnivora). If this ligament really was present, it did not insert on the epistropheus as it does in canine dogs. It is proposed here, that it inserted on the posterior aspect of the skull as in ungulates. The skeleton of Hyaenodon exhibits terrestrial and cursorial features. Its general structure was robust with a strong musculature. The fibio-tarsal complex indicates progression over uneven surface. Hyaenodon´s locomotion pattern is judged here as cursorial and interpreted in the sense that this predator was dwelling primarily on the ground with an adaptation to running. The canines of Hyaenodon are mediolaterally compressed and like those in canids and not like the rounded canines in felids. This type of canines is ideal for slashing. Thus, Hyaenodon inflicted its prey with shallow wounds and not with a killing bite like recent felids do (additional evidence comes from the non-specialized whiskers). The predation style of Hyaenodon was ambushing, although it did not succumb in a chase with most contemporaneous prey animals. It was a powerful predator in the forests of the Eocene as well as in the more open landscape of the Oligocene. Some taxonomic information can be provided as well: The tooth eruption sequence is differing between the European and the North American forms: there are significant differences in the sequence of the lower jaw (concerning the p3, the p4, the m3 and the canine) and a difference in the sequence of the upper jaw (concerning the eruption of the P1). The milk dentition in European Hyaenodon species shows different morphologies. For the first time differences are described concerning the morphology of the upper milk teeth DP3 and DP4 (development of the anterior cusp and the talonid) in the Oligocene species Hyaenodon exiguus and Hyaenodon filholi. Compared with other known juvenile material from North America and Asia, the morphology of Hyaenodon exiguus appears to be a product of European evolution. The assumption that Hyaenodon filholi was an Asian immigrant is emphasized here. Divergence within the genus was found. Some differences between the North American and the European Hyaenodon described in literature turned out to be not valid, e.g. the presence of a scapholunatum in the European taxa (based on misidentifications). However, the different tooth eruption pattern is a consistent difference, as well as the more plesiomorphic morphology of the M1 in North American forms. The root development (single- or double-rooted) of the p1 is varying, but does not give distinct clues: the oldest species show a single-rooted p1 and the Oligocene species in Europe possess a double-rooted p1. The skeleton of the European Hyaenodon shows differences between Eocene and Oligocene material. The evolution of the North American Hyaenodon is acknowledged as an own lineage. utheses.univie.ac.at/detail/16881# |
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Post by arctozilla on Jul 5, 2022 14:52:49 GMT -5
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Post by arctozilla on Jul 8, 2022 15:01:30 GMT -5
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Post by arctozilla on Jul 9, 2022 9:47:57 GMT -5
Megistotherium skull.  |
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Post by arctozilla on Jul 9, 2022 9:56:10 GMT -5
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Post by arctozilla on Jul 9, 2022 11:49:53 GMT -5
A biomechanical constraint on body mass in terrestrial mammalian predators Observations on extant mammals suggest that large body mass is selectively advantageous for a terrestrial predator on large herbivores. Yet, throughout the Cenozoic, some lineages of terrestrial mammalian predators attained greater maximal body masses than others. In order to explain this evolutionary pattern, the following biomechanical constraint on body mass is hypothesized. The stress, set up in the humerus by the bending moment of the peak ground reaction force at maximal running speed, increased with increasing body mass within a given lineage of terrestrial mammalian predators, resulting in a decreasing safety factor for the bone, until a predator could no longer attain the maximal running speed of its smaller relatives. The selective disadvantage of reduced maximal running speed prevented further increase of body mass within the lineage.This hypothesis is tested by examining the scaling of humeral dimensions and estimating maximal body masses in several lineages of terrestrial mammalian predators. Among lineages with otherwise similar postcranial skeletons, those with the more robust humeri at a given body mass attained the greater maximal body masses. Lineages with the longer deltoid ridges/deltopectoral crests of the humeri and/or the more distally located deltoid scars (suggesting the more distal insertions of the humeral flexors) at a given body mass also attained the greater maximal body masses. These results support the existence of the proposed biomechanical constraint, although paleoecological data suggest that some lineages of terrestrial mammalian predators failed to reach the limits, imposed by this constraint, because of the small size of available prey. www.researchgate.net/publication/227999071_A_biomechanical_constraint_on_body_mass_in_terrestrial_mammalian_predators |
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Post by arctozilla on Jul 11, 2022 8:00:51 GMT -5
New remains of Hyaenodontidae (Creodonta, Mammalia) from the Oligocene of Central Mongolia Abstract and Figures New specimens of hyaenodontid creodonts are described which were unearthed in Mongolia by the Austrian–Mongolian Paleontological expeditions. Five taxa are identified: Hyaenodon eminus, Hyaenodon pervagus, Hyaenodon cf. incertus, Hyaenodon cf. mongoliensis, and cf. Hyaenodon gigas. Hitherto unknown morphological details are reported for most of these species. The implications to systematic of the species and the genus Hyaenodon are discussed. These Hyaenodon remains suggest a separate evolutionary lineage, with different species in Europe and Asia, even if the genus is also known from contemporary faunas of Europe and North America. www.researchgate.net/publication/248545738_New_remains_of_Hyaenodontidae_Creodonta_Mammalia_from_the_Oligocene_of_Central_Mongolia |
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Post by arctozilla on Jul 11, 2022 14:43:32 GMT -5
CARNIVORES (CREODONTA AND CARNIVORA) FROM THE BASAL MIDDLE MIOCENE OF GEBEL ZELTEN, LIBYA, WITH A NOTE ON A LARGE AMPHICYONID FROM THE MIDDLE MIOCENE OF NGORORA, KENYA ABSTRACT Undescribed fossils from Gebel Zelten, Libya, belong to the poorly known amphicyonid Afrocyon burolleti, and to a second indeterminate amphicyonid. The Family Amphicyonidae in Africa, although considerably less diverse than in Eurasia and North America, nevertheless has a longer fossil record extending from the Early Miocene to the latest Miocene, and spanning the entire continent. A large amphicyonid from Ngorora, Kenya, is described in order to contribute to the knowledge of the family. A new species of Creodonta Anasinopa libyca from Gebel Zelten is somewhat smaller than the type species Anasinopa leakeyi from East Africa, and difffers from it by its more hypocarnivorous dentition. www.researchgate.net/publication/261361595_Carnivores_Creodonta_and_Carnivora_from_the_basal_middle_Miocene_of_Gebel_Zelten_Libya_with_a_note_on_a_large_amphicyonid_from_the_middle_Miocene_of_Ngorora_Kenya |
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Post by arctozilla on Jul 11, 2022 14:58:45 GMT -5
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Post by arctozilla on Jul 11, 2022 15:10:19 GMT -5
Razor Jaws - Prehistoric Predators
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Post by arctozilla on Jul 13, 2022 8:00:44 GMT -5
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Post by arctozilla on Apr 16, 2023 5:32:47 GMT -5
Here's weight estimations on Simbakubwa. According to Morlo carnasial ml lenght Simbakubwa weighs 1.3 tons, according to Valkenburgh m3 lenght in Felidae regression equation Simbakubwa is 1.5 tons, according to Valkenburgh m3 lenght equation for carnivorans who are larger than 100 kg Simbakubwa weighs 280 kg (the size of a large lion). However the article points out that teeth equations aren't accurately reliable.   www.researchgate.net/publication/332494825_Simbakubwa_kutokaafrika_gen_et_sp_nov_Hyainailourinae_Hyaenodonta_'Creodonta'_Mammalia_a_gigantic_carnivore_from_the_earliest_Miocene_of_Kenya |
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Post by arctozilla on Apr 16, 2023 5:36:43 GMT -5
/\ In addition no cenozoic land predator will reach 1.3 tons. That's the weight of a rhino. We just need to wait current estimations but we can still safely say that a 1+ ton creodont is unreliable due to teeth equations being unreliable.
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