Post by Infinity Blade on Aug 10, 2024 6:04:08 GMT 5
Some aquatic animals are known to ram other animals or objects aggressively. Odontocetes are the most well-known example, with dolphins being known to ram smaller sharks and porpoises, orcas ramming various prey items, and sperm and beaked whales having heads that seem specialized for ramming head-on. There are also accounts of sharks ramming divers and boats.
Here, I will compile some scientific sources that hypothesize or at least allude to the possibility of Mesozoic marine reptiles ramming other animals. This means that what I cite is not necessarily hard evidence, and can just be something as little/shaky as a researcher throwing around an idea. But if researchers thought it plausible enough to consider the behavior for certain marine reptiles, maybe it's worth thinking about for us.
Mosasaurs:
- Tylosaurine mosasaurs in particular were hypothesized to have rammed prey with their snouts by Theagarten Lingham-Soliar. This was on the basis of (1) their "exceedingly robust" internarial bars, (2) the deeply interdigitated sutures within the frontal, (3) the brain being housed in a robust bony case that formed a sliding joint with the skull roof, (4) a double locking suture between the maxilla and premaxilla, and (5) a solid bony rostrum. Other mosasaurs are thought to have had internarial bars too delicate for ramming (Lingham-Soliar, 1992).
- A subadult Mosasaurus hoffmanni specimen was found with a fatal pathology to its braincase, where the brain stem was severed and displaced. The pathology is interpreted as having been the result of a powerful blow concentrated on the prootic region. The culprit is believed to most likely have been another, larger mosasaur, namely Tylosaurus bernardi, on the basis of its ramming adaptations and the fact that it was found in Maastrichtian localities close to those where M. hoffmanni was found (Lingham-Soliar, 1998).
- The holotype specimen of M. hoffmanni was found to have had unusually rugose portions of the anterior dentary, with remodeled bone being present. The authors state that this would be an unlikely site for pathology, unless M. hoffmanni used its lower jaw for ramming. They consider it most likely that the pathology was caused by damage to the ligaments binding the intermandibular joint (Street & Caldwell, 2017).
Pliosaurs:
- Lingham-Soliar considered the possibility of a pliosaur being responsible for the braincase damage on the aforementioned subadult M. hoffmanni specimen. He considered this unlikely on the premise that not only were pliosaurs rare (Pliosauroidea as a clade actually became extinct during the Turonian), but a blow from a broad-snouted pliosaur would have caused widespread damage to the entire posterior end of the skull (Lingham-Soliar, 1998).
- A mature, 5-6 m Platypterygius specimen (SAM P14508) displays a healed pathology to its lower jaw. The authors consider the possibility that a Kronosaurus may have failed to kill the ichthyosaur with a glancing bite or ramming impact, claiming it cannot be ruled out. That the pathology was caused by a predator is considered unlikely, claiming that an aggressive encounter with another large vertebrate or intraspecific combat being more likely (Zammit & Kear, 2011).
Ichthyosaurs:
- Jurassic ichthyosaurs with fusiform "fish-like" body plans show increased evidence of rib fractures as pathologies compared to earlier Triassic ichthyosaurs. These are thought to have likely come from aggressive ramming and/or tail strikes from conspecifics, as in extant odontocetes (Pardo-Pérez et al., 2020).
- Giant ichthyosaur mandibles from the Late Triassic (e.g. the Lilstock specimens) show evidence of strong reinforcement in their bone matrices, similar to mineralized ossified tendons with high tensile strength. The function of this adaptation is unknown, as the ecology of these ichthyosaurs is itself unknown. Proposed possibilities include withstanding stress from simple opening (like in baleen whales) or withstanding stress from ramming impacts as in odontocetes (Perillo & Sander, 2024).
Here, I will compile some scientific sources that hypothesize or at least allude to the possibility of Mesozoic marine reptiles ramming other animals. This means that what I cite is not necessarily hard evidence, and can just be something as little/shaky as a researcher throwing around an idea. But if researchers thought it plausible enough to consider the behavior for certain marine reptiles, maybe it's worth thinking about for us.
Mosasaurs:
- Tylosaurine mosasaurs in particular were hypothesized to have rammed prey with their snouts by Theagarten Lingham-Soliar. This was on the basis of (1) their "exceedingly robust" internarial bars, (2) the deeply interdigitated sutures within the frontal, (3) the brain being housed in a robust bony case that formed a sliding joint with the skull roof, (4) a double locking suture between the maxilla and premaxilla, and (5) a solid bony rostrum. Other mosasaurs are thought to have had internarial bars too delicate for ramming (Lingham-Soliar, 1992).
- A subadult Mosasaurus hoffmanni specimen was found with a fatal pathology to its braincase, where the brain stem was severed and displaced. The pathology is interpreted as having been the result of a powerful blow concentrated on the prootic region. The culprit is believed to most likely have been another, larger mosasaur, namely Tylosaurus bernardi, on the basis of its ramming adaptations and the fact that it was found in Maastrichtian localities close to those where M. hoffmanni was found (Lingham-Soliar, 1998).
- The holotype specimen of M. hoffmanni was found to have had unusually rugose portions of the anterior dentary, with remodeled bone being present. The authors state that this would be an unlikely site for pathology, unless M. hoffmanni used its lower jaw for ramming. They consider it most likely that the pathology was caused by damage to the ligaments binding the intermandibular joint (Street & Caldwell, 2017).
Pliosaurs:
- Lingham-Soliar considered the possibility of a pliosaur being responsible for the braincase damage on the aforementioned subadult M. hoffmanni specimen. He considered this unlikely on the premise that not only were pliosaurs rare (Pliosauroidea as a clade actually became extinct during the Turonian), but a blow from a broad-snouted pliosaur would have caused widespread damage to the entire posterior end of the skull (Lingham-Soliar, 1998).
- A mature, 5-6 m Platypterygius specimen (SAM P14508) displays a healed pathology to its lower jaw. The authors consider the possibility that a Kronosaurus may have failed to kill the ichthyosaur with a glancing bite or ramming impact, claiming it cannot be ruled out. That the pathology was caused by a predator is considered unlikely, claiming that an aggressive encounter with another large vertebrate or intraspecific combat being more likely (Zammit & Kear, 2011).
Ichthyosaurs:
- Jurassic ichthyosaurs with fusiform "fish-like" body plans show increased evidence of rib fractures as pathologies compared to earlier Triassic ichthyosaurs. These are thought to have likely come from aggressive ramming and/or tail strikes from conspecifics, as in extant odontocetes (Pardo-Pérez et al., 2020).
- Giant ichthyosaur mandibles from the Late Triassic (e.g. the Lilstock specimens) show evidence of strong reinforcement in their bone matrices, similar to mineralized ossified tendons with high tensile strength. The function of this adaptation is unknown, as the ecology of these ichthyosaurs is itself unknown. Proposed possibilities include withstanding stress from simple opening (like in baleen whales) or withstanding stress from ramming impacts as in odontocetes (Perillo & Sander, 2024).
