Mosasaurus Vector ————————————————————————— Control: M-> Roar 1 O-> Roar 2 S-> Call 1 A-> Call 2 —————————Description——————————— Mosasaurus (/ˌmoʊzəˈsɔːrəs/; "lizard of the Meuse River") is the type genus (defining example) of the mosasaurs, an extinct group of aquatic squamate reptiles. It lived from about 82 to 66 million years ago during the Campanian and Maastrichtian stages of the Late Cretaceous. The genus was one of the first Mesozoic marine reptiles known to science—the first fossils of Mosasaurus were found as skulls in a chalk quarry near the Dutch city of Maastricht in the late 18th century, and were initially thought to be crocodiles or whales. One skull discovered around 1780 was famously nicknamed the "great animal of Maastricht". In 1808, naturalist Georges Cuvier concluded that it belonged to a giant marine lizard with similarities to monitor lizards but otherwise unlike any known living animal. This concept was revolutionary at the time and helped support the then-developing ideas of extinction. Cuvier did not designate a scientific name for the animal; 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. The exact affinities of Mosasaurus as a squamate remain controversial, and scientists continue to debate whether its closest living relatives are monitor lizards or snakes. The largest species, M. hoffmannii, is estimated to measure up to 12 meters (39 ft) in maximum length, making it one of the largest mosasaurs. The skull of Mosasaurus had robust jaws and strong muscles capable of powerful bites using dozens of large teeth adapted for cutting prey. Its four limbs were shaped into paddles to steer the animal underwater. Its tail was long and ended in a downward bend and a paddle-like fluke. Mosasaurus possessed 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. There is considerable morphological variability across the currently-recognized species in Mosasaurus—from the robustly-built M. hoffmannii to the slender and serpentine M. lemonnieri—but an unclear diagnosis (description of distinguishing features) of the type species M. hoffmannii led to a historically problematic classification. As a result, more than fifty species have been attributed to the genus in the past. A redescription of the type specimen in 2017 helped resolve the taxonomy issue and confirmed at least five species to be within the genus. Another five species still nominally classified within Mosasaurus are planned to be reassessed. Mosasaurus was a type of derived mosasaur, or a latecoming member with advanced evolutionary traits such as a fully aquatic lifestyle. As such, it had a streamlined body, an elongated tail ending with a downturn supporting a two-lobed fin, and two pairs of flippers. While in the past derived mosasaurs were depicted as akin to giant flippered sea snakes, it is now understood that they were more similar in build to other large marine vertebrates such as ichthyosaurs, marine crocodylomorphs, and archaeocete whales through convergent evolution. The type species, M. hoffmannii, is one of the largest marine reptiles known, though knowledge of its skeleton remains incomplete as it is mainly known from skulls. : 100 Russell (1967) wrote that the length of the jaw equalled one tenth of the body length in the species. : 210 Based on this ratio, Grigoriev (2014) used the largest lower jaw attributed to M. hoffmannii (CCMGE 10/2469, also known as the Penza specimen; measuring 171 centimeters (67 in) in length) to estimate a maximum length of 17.1 meters (56 ft). Using a smaller partial jaw (NHMM 009002) measuring 90 centimeters (35 in) and "reliably estimated at" 160 centimeters (63 in) when complete, Lingham-Soliar (1995) estimated a larger maximum length of 17.6 meters (58 ft) via the same ratio. No explicit justification for the 1:10 ratio was provided in Russell (1967), and it has been considered to be probably overestimated by Cleary et al. (2018). In 2014, Federico Fanti and colleagues alternatively argued that the total length of M. hoffmannii was more likely closer to seven times the length of the skull, which was based on a near-complete skeleton of the related species Prognathodon overtoni. The study estimated that an M. hoffmannii individual with a skull measuring more than 145 cm (57 in) would have been up to or more than 11 meters (36 ft) in length and weighed 10 metric tons (11 short tons) in body mass. Using the same ratio, Gayford et al. (2024) calculated the total length for the Penza specimen to be 12 meters (39 ft). ——————————Credits——————————— Earth Wikipedia Museum Scientists Cretaceous Mosasaurus Raptor_Saurus If Used, Credit Me. Music: Teeth —————————————————————————
