One specimen traditionally attributed to M. lemonnieri has serration-like features in its cutting edges. Scientists believe this specimen likely belongs to a different species. [40]

a b c d Mike Everhart (May 14, 2010). " Mosasaurus hoffmanni-The First Discovery of a Mosasaur?". Oceans of Kansas. Archived from the original on September 4, 2019 . Retrieved November 6, 2019. Description [ edit ] Life restoration of a mosasaur ( Platecarpus tympaniticus) informed by fossil skin impressions Scientists during the early and mid-1800s initially imagined Mosasaurus as an amphibious marine reptile with webbed feet and limbs for walking. This was based on fossils like the M. missouriensis holotype, which indicated an elastic vertebral column that Goldfuss in 1845 saw as evidence of an ability to walk and interpretations of some phalanges as claws. [30] In 1854, Hermann Schlegel proved how Mosasaurus actually had fully aquatic flippers. He clarified that earlier interpretations of claws were erroneous and demonstrated how the phalanges show no indication of muscle or tendon attachment, which would make walking impossible. They are also broad, flat, and form a paddle. 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. [16] [43] Takuya Konishi; Michael W. Caldwell; Tomohiro Nishimura; Kazuhiko Sakurai; Kyo Tanoue (2015). "A new halisaurine mosasaur (Squamata: Halisaurinae) from Japan: the first record in the western Pacific realm and the first documented insights into binocular vision in mosasaurs". Journal of Systematic Palaeontology. 14 (10): 809–839. doi: 10.1080/14772019.2015.1113447. S2CID 130644927.

5 Concluding remarks and future research

A study published in 2013 by Schulp and colleagues specifically tested how mosasaurs such as M. hoffmannii and P. saturator were able to coexist in the same localities through δ 13C analysis. The scientists utilized an interpretation that differences in isotope values can help explain the level of resource partitioning because it is influenced by multiple environmental factors such as lifestyle, diet, and habitat preference. Comparisons between the δ 13C levels in multiple teeth of M. hoffmannii and P. saturator from the Maastrichtian-age Maastricht Formation showed that while there was some convergence between certain specimens, the average δ 13C values between the two species were on average different. This is one indication of niche partitioning, where the two mosasaur genera likely foraged in different habitats or had different specific diets to coexist without direct competitive conflict. The teeth of P. saturator are much more robust than those of M. hoffmannii and were specifically equipped for preying on robust prey like turtles. While M. hoffmannii also preyed on turtles, its teeth were built to handle a wider range of prey less suited for P. saturator. [61] a b c William B. Gallagher (2005). "Recent mosasaur discoveries from New Jersey and Delaware, USA: stratigraphy, taphonomy and implications for mosasaur extinction". Netherlands Journal of Geosciences. 84 (3): 241–245. doi: 10.1017/S0016774600021028. The number of prisms in M. conodon and number of lingual prisms in M. lemonnieri are uncertain. [42] Richard Harlan (1839). "Notice of the discovery of Basilosaurus and Batrachiotherium". Proceedings of the Geological Society of London. 3: 23–24. Main article: Research history of Mosasaurus Discovery and identification [ edit ] TM 7424, the first known specimen of M. hoffmannii

a b c d Gorden L. Bell Jr. (1997). "A Phylogenetic Revision of North American and Adriatic Mosasauroidea". Ancient Marine Reptiles. Academic Press. pp.293–332. doi: 10.1016/b978-012155210-7/50017-x. ISBN 978-0-12-155210-7. Tamaki Sato (2003). " Terminonatator ponteixensis, a new elasmosaur (Reptilia; Sauropterygia) from the Upper Cretaceous of Saskatchewan". Journal of Vertebrate Paleontology. 23 (1): 89–103. doi: 10.1671/0272-4634(2003)23[89:tpanes]2.0.co;2. S2CID 130373116.

4 Age of the Pondoland Mosasaurids

The type species, M. hoffmannii, is one of the largest marine reptiles known, [50] [46] though knowledge of its skeleton remains incomplete as it is mainly known from skulls. [7] Russell (1967) wrote that the length of the jaw equalled one tenth of the body length in the species. [38] 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 (67in) in length) to estimate a maximum length of 17.1 meters (56ft). [46] Using a smaller partial jaw ( NHMM 009002) measuring 90 centimeters (35in) and "reliably estimated at" 160 centimeters (63in) when complete, Lingham-Soliar (1995) estimated a larger maximum length of 17.6 meters (58ft) via the same ratio. [d] [50] No explicit justification for the 1:10 ratio was provided in Russell (1967), [38] and it has been considered to be probably overestimated by Cleary et al. (2018). [51] 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 145cm (57in) would have been up to or more than 11 meters (36ft) in length and weighed 10 metric tons (11 short tons) in body mass. [52] Mentioning the Penza specimen, Gregory S. Paul estimated in his 2022 book, The Princeton Field Guide to Mesozoic Sea Reptiles, a shorter maximum length for M. hoffmannii of 13 meters (43ft) and a body mass of 5.5 metric tons (6.1 short tons). [53] The Penza specimen, one of the largest known fossils of Mosasaurus [46]

Michael J. Polcyn; Louis L. Jacobs; Ricardo Araújo; Anne S.Schulp; Octávio Mateus (2014). "Physical drivers of mosasaur evolution" (PDF). Palaeogeography, Palaeoclimatology, Palaeoecology. 400 (15): 17–27. Bibcode: 2014PPP...400...17P. doi: 10.1016/j.palaeo.2013.05.018. One enigmatic occurrence of Mosasaurus sp. fossils is in the Hornerstown Formation, a deposit typically dated to be from the Paleocene Danian age, which was immediately after the Maastrichtian age. The fossils were found in association with fossils of Squalicorax, Enchodus, and various ammonites within a uniquely fossil-rich bed at the base of the Hornerstown Formation known as the Main Fossiliferous Layer. This does not mean Mosasaurus and its associated fauna survived the K-Pg extinction. 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. Evidence of reworking typically comes from fossils worn down due to further erosion during their exposure at the time of redeposition. Many of the Mosasaurus fossils from the Main Fossiliferous Layer consist of isolated bones commonly abraded and worn, but the layer also yielded better-preserved Mosasaurus remains. Another explanation suggests the Main Fossiliferous Layer is a Maastrichtian time-averaged remanié deposit, which means it originated from a Cretaceous deposit with winnowed low-sediment conditions. 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. [2] See also [ edit ] Isolated bones suggest some M. hoffmannii may have exceeded the lengths of the Penza specimen. One such bone is a quadrate (NHMM 003892) which is 150% larger than the average size, which Everhart and colleagues in 2016 reported can be extrapolated to scale an individual around 18 meters (59ft) in length. It was not stated whether they applied Russell's 1967 ratio. [54] José P. O'Gorman; Karen M. Panzeri; Marta S. Fernández; Sergio Santillana; Juan J. Moly; Marcelo Reguero (2018). "A new elasmosaurid from the upper Maastrichtian López de Bertodano Formation: new data on weddellonectian diversity". Alcheringa: An Australasian Journal of Palaeontology. 42 (4): 575–586. Bibcode: 2018Alch...42..575O. doi: 10.1080/03115518.2017.1339233. S2CID 134265841.

Dental Adaptations for Preying on Different Types of Food

a b c d e f g h i j k Nathalie Bardet; Xabier Pereda Suberbiola; Mohamed Iarochene; Fatima Bouyahyaoui; Baadi Bouya; Mbarek Amaghzaz (2004). " Mosasaurus beaugei Arambourg, 1952 (Squamata, Mosasauridae) from the Late Cretaceous phosphates of Morocco". Geobios. 37 (2004): 315–324. Bibcode: 2004Geobi..37..315B. doi: 10.1016/j.geobios.2003.02.006. S2CID 127441579. a b c d Florence Pieters; Peggy G. W. Rompen; John W. M. Jagt; Nathalie Bardet (2012). "A new look at Faujas de Saint-Fond's fantastic story on the provenance and acquisition of the type specimen of Mosasaurus hoffmanni MANTELL, 1829". Bulletin de la Société Géologique de France. 183 (1): 55–65. doi: 10.2113/gssgfbull.183.1.55. a b c Mike Everhart (October 21, 2013). "The Goldfuss Mosasaur". Oceans of Kansas. Archived from the original on June 2, 2019 . Retrieved November 10, 2019. Richard Harlan (1834). "Notice of the Discovery of the Remains of the Ichthyosaurus in Missouri, N. A.". Transactions of the American Philosophical Society. 4: 405–408. doi: 10.2307/1004839. JSTOR 1004839.