Post by Deleted on Dec 30, 2022 21:02:30 GMT
Kaprosuchus
Kaprosuchus is an extinct genus of mahajangasuchid crocodyliform known from a single nearly complete skull collected from the Upper Cretaceous Echkar Formation of Niger. The name means "boar crocodile" in reference to its unusually large caniniform teeth which resemble those of a boar. Kaprosuchus is known from a nearly complete skull 507 mm in length in which the lower jaw measured 603 mm long, whilst the entire animal is originally estimated to have been around 6 metres (20 ft) in length, but later comparisons to similar crocodiles suggest a total estimated body length approximately 3.3 metres (11 ft). Kaprosuchus possesses three sets of tusk-like caniniform teeth that project above and below the skull, one of which in the lower jaw fits into notches in upper jaw. This type of dentition is not seen in any other known crocodyliform. Another unique characteristic is the presence of large, rugose horns formed from the squamosal and parietal bones that project posteriorly from the skull. Its snout shows generalized proportions and the naris is positioned dorsally. In Kaprosuchus many teeth are hypertrophied and labiolingually (laterally) compressed, unlike those of crocodyliforms with similarly shallow snouts, which are usually subconical and of moderate length. Another difference between the skull of Kaprosuchus and those of crocodyliforms that also possess dorsoventrally compressed snouts is the great depth of the posterior portion of the skull. In Kaprosuchus, the orbits (i.e., eye sockets) open laterally and are angled slightly forward rather than upward. The orbits turned forward suggest that there was somewhat stereoscopic vision, i.e., an overlap in the visual field of the animal. The surfaces of the premaxillae are rugose with the edges elevated above the body of the bone, suggesting that a keratinous shield would have been supported by the rugosities at the tip of the snout. Kaprosuchus is thought to have been a primarily if not exclusively terrestrial predator. Evidence for this behavior includes the positioning of the orbits laterally and somewhat anteriorly, which suggests an overlap in vision. This is unlike many other neosuchians, including extant crocodilians, in which the orbits are positioned dorsally as an adaptation to aquatic predation where the head can be held underwater while the eyes remain above the surface. Additional support for terrestrial predation can be found in the teeth and jaws. The enlarged caniniforms are sharp-edged and relatively straight, unlike the fluted, subconical, recurved teeth of aquatic crocodyliforms. Because the retroarticular process of the lower jaw is long, it is likely that the jaws were able to open relatively quickly with a large gape to allow for the opposing caniniforms to clear one another. The fused nasal bones are thought to have provided reinforcement for the jaws against compression associated with a powerful bite. The telescoped, dorsally positioned external nares are seen as protection against impact if the animal rammed prey with its robust snout. The keratinous shield thought to have covered the tip of the snout would have provided further protection.
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Quinkana
Quinkana is an extinct genus of mekosuchine crocodile that lived in Australia from ~24 million years ago to ~40,000 years ago. By the Pleistocene Quinkana had become one of the top terrestrial predators of Australia, possessing long legs and ziphodont teeth (lateromedially compressed, recurved and serrated). Quinkana comes from the "Quinkans", a legendary folk from Aboriginal myths. Quinkana fortirostrum has been estimated to have exceeded 5 metres (16 ft) in length, making it at the time one of Australia's largest predators.
Kaprosuchus is an extinct genus of mahajangasuchid crocodyliform known from a single nearly complete skull collected from the Upper Cretaceous Echkar Formation of Niger. The name means "boar crocodile" in reference to its unusually large caniniform teeth which resemble those of a boar. Kaprosuchus is known from a nearly complete skull 507 mm in length in which the lower jaw measured 603 mm long, whilst the entire animal is originally estimated to have been around 6 metres (20 ft) in length, but later comparisons to similar crocodiles suggest a total estimated body length approximately 3.3 metres (11 ft). Kaprosuchus possesses three sets of tusk-like caniniform teeth that project above and below the skull, one of which in the lower jaw fits into notches in upper jaw. This type of dentition is not seen in any other known crocodyliform. Another unique characteristic is the presence of large, rugose horns formed from the squamosal and parietal bones that project posteriorly from the skull. Its snout shows generalized proportions and the naris is positioned dorsally. In Kaprosuchus many teeth are hypertrophied and labiolingually (laterally) compressed, unlike those of crocodyliforms with similarly shallow snouts, which are usually subconical and of moderate length. Another difference between the skull of Kaprosuchus and those of crocodyliforms that also possess dorsoventrally compressed snouts is the great depth of the posterior portion of the skull. In Kaprosuchus, the orbits (i.e., eye sockets) open laterally and are angled slightly forward rather than upward. The orbits turned forward suggest that there was somewhat stereoscopic vision, i.e., an overlap in the visual field of the animal. The surfaces of the premaxillae are rugose with the edges elevated above the body of the bone, suggesting that a keratinous shield would have been supported by the rugosities at the tip of the snout. Kaprosuchus is thought to have been a primarily if not exclusively terrestrial predator. Evidence for this behavior includes the positioning of the orbits laterally and somewhat anteriorly, which suggests an overlap in vision. This is unlike many other neosuchians, including extant crocodilians, in which the orbits are positioned dorsally as an adaptation to aquatic predation where the head can be held underwater while the eyes remain above the surface. Additional support for terrestrial predation can be found in the teeth and jaws. The enlarged caniniforms are sharp-edged and relatively straight, unlike the fluted, subconical, recurved teeth of aquatic crocodyliforms. Because the retroarticular process of the lower jaw is long, it is likely that the jaws were able to open relatively quickly with a large gape to allow for the opposing caniniforms to clear one another. The fused nasal bones are thought to have provided reinforcement for the jaws against compression associated with a powerful bite. The telescoped, dorsally positioned external nares are seen as protection against impact if the animal rammed prey with its robust snout. The keratinous shield thought to have covered the tip of the snout would have provided further protection.
vs
Quinkana
Quinkana is an extinct genus of mekosuchine crocodile that lived in Australia from ~24 million years ago to ~40,000 years ago. By the Pleistocene Quinkana had become one of the top terrestrial predators of Australia, possessing long legs and ziphodont teeth (lateromedially compressed, recurved and serrated). Quinkana comes from the "Quinkans", a legendary folk from Aboriginal myths. Quinkana fortirostrum has been estimated to have exceeded 5 metres (16 ft) in length, making it at the time one of Australia's largest predators.
