Holwerda wants to reveal more about these ancient interrelationships, which is tricky business. [72] The cladogram on the right (Topology B) is modified from Street's 2016 doctoral thesis proposing a revision to the Mosasaurinae, with proposed new taxa and renamings in single quotations. [40], The fifth species M. beaugei was described by Camille Arambourg in 1952 from isolated teeth originating from phosphate deposits in the Oulad Abdoun Basin and the Ganntour Basin in Morocco. These and other features support a large and powerful paddle-like fluke in Mosasaurus. Such a trait is unique among squamates, the only known exception being the Argentine black and white tegu, which can maintain partial endothermy. [5], The palate, which consists of the pterygoid bones, palatine bone, and nearby processes of other bones, is tightly packed to provide greater cranial stability. Mosasaurs are Cretaceous marine lizards, (probably) closely related to gila monsters and kin (the monstersaurians) and monitor lizards and kin (the goannasaurians), and well known for evolving. The overall structure of the paddle is compressed, similar to in Plotosaurus, and was well-suited for faster swimming. Until recent decades, many living venomous lizards and snakes werent even recognized as such by scientists, typically because the species were too small to affect humans or the venom in question wasnt directly fatal. [30] In 1854, Hermann Schlegel proved how Mosasaurus actually had fully aquatic flippers. The massive extinct lizard that dominated Cretaceous oceans, but was not a dinosaur. This study was conducted on only one tooth and may not represent the exact durations of, The number of caudal vertebrae is not fully certain for, Street & Caldwell (2017) revised this assessment of. [129], One enigmatic occurrence of Mosasaurus sp. These localities include the Midwest and East Coast of the United States, Canada, Europe, Turkey, Russia, the Levant, the African coastline from Morocco[101] to South Africa, Brazil, Argentina, and Antarctica. [102] Mosasaurus was not well-represented: the distribution of M. beaugei was restricted to Morocco and Brazil and isolated teeth from Syria suggested a possible presence of M. lemonnieri, although M. hoffmannii also had some presence throughout the province. [55] Paul (2022) offered a larger maximum estimate for the species at 12 meters (39ft) in length and 4.5 metric tons (5.0 short tons) in body mass. Mosasaurs - Encyclopedia of Alabama Mosasaurus Facts and Figures - ThoughtCo ; SDSM 452)[7][11] has seven cervical (neck) vertebrae, thirty-eight dorsal vertebrae (which includes thoracic and lumbar vertebrae) in the back, and eight pygal vertebrae (front tail vertebrae lacking haemal arches) followed by sixty-eight caudal vertebrae in the tail. How are they killing it? [53], The skull of Mosasaurus is conical and tapers off to a short snout which extends a little beyond the frontmost teeth. In M. lemonnieri, these olfactory organs, although still small, are better developed and have some components lacking in M. hoffmannii. [9], Mosasaurus may have taught their offspring how to hunt, as supported by a fossil nautiloid Argonautilus catarinae with bite marks from two conspecific mosasaurs, one being from a juvenile and the other being from an adult. This is the focus of ongoing research by Femke Holwerda, a postdoctoral research fellow at the Royal Tyrrell Museum of Palaeontology, who presented what she categorized as a pilot study at the SVP annual meeting. Mosasaurus was a predator possessing excellent vision to compensate for its poor sense of smell, and a high metabolic rate suggesting it was endothermic ("warm-blooded"), an adaptation in squamates only found in mosasaurs. Mosasaurs may no longer exist, but almost everything else she studies has modern descendants. The margin provided a warm-temperate climate with habitats dominated by mosasaurs and sea turtles. [7] Second, the studies relied on an unclean and shaky taxonomy of the Mosasaurus genus due to the lack of a clear holotype diagnosis, which may have been behind the genus's paraphyletic status. Analysis of the tooth marks by a 2004 study by Kauffman concluded that the mosasaurs were either Mosasaurus or Platecarpus. [88], Carbon isotope studies on fossils of multiple M. hoffmannii individuals have found extremely low values of 13C, the lowest in all mosasaurs for the largest individuals. [75], The following cladogram on the left (Topology A) is modified from a maximum clade credibility tree inferred by a Bayesian analysis in the most recent major phylogenetic analysis of the Mosasaurinae subfamily by Madzia & Cau (2017), which was self-described as a refinement of a larger study by Simes et al. This, Zietlow asserts, indicates they probably ate what they could swallow whole. [42], Like all mosasaurs, Mosasaurus had four types of teeth, classified based on the jaw bones they were located on. maximus-hoffmanni. Traditional interpretations have estimated the maximum length of the largest species, M. hoffmannii, to be up to 17.1 meters (56ft), making it one of the largest mosasaurs, although some scientists consider this an overestimation with recent estimates suggesting a length closer to 13 meters (43ft). [7] Russell (1967) wrote that the length of the jaw equalled one tenth of the body length in the species. There is still much work to be done by all three of these paleontologists, and both groups indicate there are many questions they have yet to answer. ; Mosasaurs were a group of large, aquatic squamates (relatives of modern-day lizards and snakes) which became the . [56][57] Street (2016) noted that large M. missouriensis individuals typically had skulls exceeding lengths of 1 meter (3.3ft). The validity of some of these genera is disputed as they are primarily based on isolated teeth. According to one hypothesis, the fossils may have originated from an earlier Cretaceous deposit and were reworked into the Paleocene formation during its early deposition. Cuvier did not designate a scientific name for the new animal, and this was done by William Daniel Conybeare in 1822 when he named it Mosasaurus in reference to its origin in fossil deposits near the Meuse River. Mosasaurus faced competition with other large predatory mosasaurs such as Prognathodon and Tylosauruswhich were known to feed on similar preythough they were able to coexist in the same ecosystems through niche partitioning. [99][97] Some areas in Europe and South Dakota have yielded concentrated assemblages of juvenile M. hoffmannii, M. missouriensis and/or M. lemonnieri. These cranial structures are united by strong interlocking sutures formed to resist compression and shear forces caused by a downward thrust of the lower jaw muscles or an upward thrust of prey. [50] The texture of the bones is virtually identical with in modern whales, which indicates Mosasaurus possessed a high range of aquatic adaptation and neutral buoyancy as seen in cetaceans. Changing temperatures and an abundance in marine life were characteristic of these localities. In each jaw row, from front to back, Mosasaurus had: two premaxillary teeth, twelve to sixteen maxillary teeth, and eight to sixteen pterygoid teeth on the upper jaw and fourteen to seventeen dentary teeth on the lower jaw. has also been described. Absent direct evidence like gut contents, her research involves considerable detective work. This was by observing the von Ebner lines, incremental marks in dentin that form daily. [85] Other Antarctic marine reptiles included elasmosaurid plesiosaurs like Aristonectes and another indeterminate elasmosaurid. Yet, most mosasaurs dont seem to have had strong bites proportionally for how big they are, she said. Various partial skeletons of M. conodon, M. hoffmannii, and M. missouriensis suggest M. conodon likely had up to thirty-six dorsal vertebrae and nine pygal vertebrae; M. hoffmannii had likely up to thirty-two dorsal vertebrae and ten pygal vertebrae;[i][11][36] and M. missouriensis around thirty-three dorsal vertebrae, eleven pygal vertebrae, and at least seventy-nine caudal vertebrae. A third hypothesis proposes that the layer is a lag deposit of Cretaceous sediments forced out by a strong impact by a tsunami, and what remained was subsequently refilled with Cenozoic fossils. [50][61] Fauna likely preyed upon by the genus include bony fish, sharks, cephalopods, birds, and marine reptiles such as other mosasaurs[61] and turtles. saturator. hoffmannii had fourteen to sixteen maxillary teeth, fourteen to fifteen dentary teeth, and eight pterygoid teeth;[11][46][50] M. missouriensis had fourteen to fifteen maxillary teeth, fourteen to fifteen dentary teeth, and eight to nine pterygoid teeth;[9][42][64] M. conodon had fourteen to fifteen maxillary teeth, sixteen to seventeen dentary teeth, and eight pterygoid teeth;[11][42] M. lemonnieri had fifteen maxillary teeth, fourteen to seventeen dentary teeth, and eleven to twelve pterygoid teeth;[36][11][42] and M. beaugei had twelve to thirteen maxillary teeth, fourteen to sixteen dentary teeth, and six or more pterygoid teeth. The earliest mosasaurs were most likely fish eaters. Tyrannosaurs may have ruled the land, but mosasaurs ruled the seas. And this hinge is sometimes looser and sometimes more rigid, depending on the species, but they all have basically a joint in the middle of the lower jaw. That joint allows motion between the two halves. The eye sockets were located at the sides of the skull, which created a narrow field of binocular vision at around 28.5[50][87] but alternatively allowed excellent processing of a two-dimensional environment, such as the near-surface waters inhabited by Mosasaurus. ;[58] Paul (2022) estimated an individual of that size to weigh 700 kilograms (1,500lb). Henry Sharpe, an undergraduate student at the University of Alberta, and Amelia R. Zietlow, a PhD candidate at the Richard Gilder Graduate School at the American Museum of Natural History in New York, described some of their ongoing research into mosasaur jaws. Mosasaur - Wikipedia [29] The rest of the skull had been discovered earlier by a fur-trapper, and it eventually came under the possession of prince Maximilian of Weid-Neuwied between 1832 and 1834. A Mosasaur's Last Meal - National Geographic Her research so far indicates that the various mosasaur species in the Bearpaw Sea lived in different areas and ate different things, but more data is needed. [2], Distribution, ecosystem, and ecological impact. mosasaur, (family Mosasauridae), extinct group of aquatic lizards that attained a high degree of adaptation to the marine environment and were distributed worldwide during the Cretaceous Period (145.5 million to 66 million years ago). In 2004, Lingham-Soliar observed that if these injuries were indeed the result of an intraspecific attack, then there is a pattern of them concentrating in the skull region. [67] The tail vertebrae gradually shorten around the center of the tail and lengthen behind the center, suggesting rigidness around the tail center and excellent flexibility behind it. [39] However, the need for more research to confirm any hypotheses of synonymy was expressed. [11][32] In his description, Cope does not provide the etymology for the specific epithet conodon,[31] but it is suggested that it could be a portmanteau meaning "conical tooth", derived from the Ancient Greek (knos, "cone") and (odn, "tooth"), probably in reference to conical surface teeth smooth of the species. The coloration of mosasaurs was unknown until 2014, when the findings of Johan Lindgren of Lund University and colleagues revealed the pigment melanin in the fossilized scales of a mosasaur. [22] Richard Ellis speculated in 2003 that this may have been the earliest discovery of the second species M. missouriensis,[23] although competing speculations exist. The skull of Mosasaurus was equipped with robust jaws capable of swinging back and forth and strong muscles capable of powerful bites using dozens of large teeth adapted for cutting prey. Schlegel's hypothesis was largely ignored by contemporary scientists but became widely accepted by the 1870s when Othniel Charles Marsh and Cope uncovered more complete mosasaur remains in North America. 'Sea monsters' were real millions of years ago. New fossils tell about They had fins, long tails, mouths full of teeth, and could be anywhere from 10 to 50 feet in length. This means they can not only move each separate jaw bone but both sets of teeth independently as they grab and swallow their prey. [MUSIC] Inside the American Museum of Natural History's Hall of Vertebrate Origins, where fossils of a large sea turtle and long-necked swimming reptile hang from the ceiling. It has been pointed out how 13C can be influenced by other factors in an animal's lifestyle, such as diet and diving behavior. [50], Like all mosasaurs, the lower jaws of Mosasaurus could swing forward and backward. [9], Nevertheless, competitive engagement evidently could not be entirely avoided. [102] In certain areas such as Belgium, other Mosasaurus species like M. lemonnieri were instead the dominant species, where it's occurrences greatly outnumber those of other large mosasaurs. Theagarten Lingham-Soliar suggested two reasons for this neglect. [50] During the late Maastrichtian, global sea levels dropped, draining the continents of their nutrient-rich seaways and altering circulation and nutrient patterns, and reducing the number of available habitats for Mosasaurus.
