Jurassic World 3 is released, and the top Mosasaur is criticized for not appearing enough?

Breaking news: There’s a new movie in the “Jurassic World” series!

"Jurassic World: Domination" was recently released. This is the sixth and final film in the Jurassic series. Since 1993, the "Jurassic Park" series of films has become a classic in the hearts of movie fans around the world, and it has also made the image of dinosaurs come alive in front of modern people.

(A little spoiler) I heard that in "Jurassic World 3", all kinds of centaurs and dinosaurs have returned, and there will be a family-friendly brawl in the end.

Movie review from Douban

But it's a bit regrettable that the popular king Mosasaur showed up too little, which was not exciting enough...

Everyone hopes to shoot more Mosasaur, and even hopes to shoot a separate series of Mosasaur. It is indeed the top among dinosaurs~

Today, we will explain to you scientifically what kind of dragon is the Mosasaur that we all love, and why it looks different from other dragons?

1. What kind of animal was Mosasaur: a snake or a lizard?

Workers digging up Mosasaur fossils in the Maastricht limestone quarry (Source: Histoire naturelle de la Montagne de Saint-Pierre de Maestricht)

What kind of animal is Mosasaur?

The first known fossil material (skull) of Mosasaur was discovered in the 1760s in an underground quarry on a hill called "St. Peter" near Maastricht, the Netherlands.

After several twists and turns, it was finally collected in the Thales Museum in Haarlem, the Netherlands (No. TM7424).

The first batch of Mosasaur fossils still collected in the Telus Museum, numbered TM7424 (Source: Oceans of Kansas)

TM7424 was of particular interest to retired Dutch army doctor Johan Hofmann, who had collected similar fossils as early as 1770 and believed the animal was a crocodile.

However, later historians believed that when Hoffman was restoring the Mosasaur fossil, he distorted the presentation of some of the toe bones of the Mosasaur, creating the illusion that it had "claws". This illusion reinforced Hoffman's perception that the Mosasaur was a crocodile.

Dutch biologist Petrus Kamper strongly disagreed with Hoffmann's view. In 1786, he studied and concluded that TM7424 was not a crocodile, but a whale, for the following reasons:

1. It has strong tooth roots like a sperm whale;

2. The "wing bones" in its skull are not found in crocodiles, but many fish have wing bones (Kemper mistakenly believed that whales were fish at the time, hahaha);

3. Its toe bones are very similar to those of whales;

4. All the fossils found at this fossil site were of marine animals, so they could only be whales (but at that time Camper did not know that crocodiles also lived in the sea).

Around the 1770s and 1780s, the second complete Mosasaur skull fossil was unearthed. After many twists and turns, it was finally collected in the National Museum of Natural History of France in 1795 (No.: MNHN AC 9648).

In 1799, the great French naturalist Georges Cuvier studied MNHN AC 9648 and found that its anatomical features were more similar to those of existing monitor lizards, so he determined that it was an extinct large marine lizard.

The current mainstream view in academia is that mosasaurs belong to the order Squamata and are closely related to modern snakes and monitor lizards.

Trivia: In 1822, British paleontologist William Daniel Conybeare named the Mosasaur "Mosasaurus" after the Meuse River that flows through Maastricht, where the Mosasaur fossils were found. The reason why it was translated into Chinese as Mosasaur is unknown.

The second Mosasaur skull fossil, numbered MNHN AC 9648 (source: MWAK)

2. How did Mosasaurs give birth: Ovoviviparous

Was Mosasaur an oviparous animal like most reptiles?

In the early 20th century, scholars represented by American paleontologist Samuel Wendell Williston believed that mosasaurs were oviparous and that adult mosasaurs living in the ocean might have entered inland through rivers to lay eggs. The "Mosasaur oviparous school" was popular for a long time.

In 1996, paleontologist Michael Wayne Caldwell and his colleagues at the University of Alberta in Canada discovered that an adult Carsosaurus (a mosasaur) fossil contained no less than three Carsosaurus juveniles (note: juveniles, not eggs) in its abdominal cavity while observing a batch of southern European fossil materials. This is an important example of ovoviviparity in mosasaurs.

Reconstruction of an adult Catosaurus with a Catosaurus larva in its abdomen (Source: Proceedings: Biological Sciences)

In 2015, a research team led by Dr. Adam Behlke of Yale University re-examined the remains of an "ancient seabird" that had been collected for many years in the Peabody Museum of Natural History at Yale University. They found that this so-called "ancient seabird" had a body shape (about 0.66 meters) that was consistent with ancient seabirds, and other features such as jaws and teeth were all owned by Mosasaurs. Therefore, it was determined that the fossil should be the remains of a young Mosasaur.

In addition, the sediments at the site where the fossils were unearthed show that this area was originally an "open sea area". The "appearance of young Mosasaurs in the open sea area" indicates that adult Mosasaurs were likely to give birth directly in the deep sea, which is another example of ovoviviparity among Mosasaurs.

85 million years ago, female Mosasaurs gave birth directly to their young in the deep sea (illustration by Julius Csotonyi)

3. How big could a Mosasaur grow?

According to current fossil materials, there are many large creatures in the Mosasaur family that are over 10 meters long. Here are three representative examples.

The first is Mosasaurus lemonnieri, described by Belgian paleontologist Louis Dollo in 1889. This Mosasaur is unique to Belgium and the Netherlands. It has a slender appearance, like a "sea snake". Louis Dollo estimated its body length based on its skull, which means that the body length of Mosasaur Lemonnieri may be comparable to that of modern killer whales (also known as orcas).

Light grey is Hoffmann's Mosasaur, orange is Lemonnier's Mosasaur, blue is Missouri's Mosasaur, purple is Borg's Mosasaur (illustration by Slate Weasel)

Hainosaurus bernardi was described by Louis Dollo in 1885. In 1967, Russell, DA initially estimated that its body length could reach 17 meters. In 1998, Lingham Soliar revised this data to 15 meters, and in 2005, Johan Lindgren revised this data to 12.2 meters.

Although the size of Hainosaurus has been repeatedly discounted by scholars, a combination of these three versions of data shows that the body length of Hainosaurus may still be comparable to that of modern behemoths such as the humpback whale.

Remember the "second Mosasaur skull discovered in the 1770s-1780s" we mentioned above?

In 1829, it was named "Mosasaurus hoffmannii" by British paleontologist Gideon Mantell after the old man Hoffmann, and Hoffmann's Mosasaur also became the "type species" of the genus Mosasaur.

The body size of Hoffmann's Mosasaur is "unrivaled among all dragons". Dimitry V. Grigoriev believed in his 2014 study that its body length could reach 17.1 meters. In 2013, AS Schulp et al. gave a relatively conservative figure of 14 meters.

Combining the above two data, the body length of Hofmann's Mosasaur is roughly equivalent to that of male sperm whales among living sperm whales (except for extremely large male whales whose body length can exceed 20 meters).

Size comparison between Hoffmann's Mosasaur and humans (Source: fossilera)

[Type species] When scholars establish a genus, they must specify a species as the basis for the establishment of the genus. This designated species is the type species of the genus, which represents the biological characteristics of the genus.

4. How small was the “little” Mosasaur?

Hardcore "sea reptile enthusiasts" may be familiar with a painting like this: "In the Cretaceous ocean, several huge sharks are attacking a smaller Mosasaur."

Those huge sharks are the "strong competitors" of Mosasaur in the Cretaceous period - Cretoxyrhina, also known as Cretoxyrhina, golden shark, etc. British scholar C. Mantelli believes that the largest individual can reach 8 meters.

The poor "little Mosasaur" in the painting is a Clidastes. American paleontologist Cope, ED, believes that the average length of Clidastes was only 2-4 meters, and the largest individual was only about 6 meters.

The largest individual of the Cretaceous thorny shark (purple), the largest individual in North America (green), and the complete specimen (red) compared with the human body size (drawn by Macrophysete)

Comparison of the size of a spondylosaur and a human (by Slate Weasel)

Carinodens, discovered in the Netherlands in 1913, was even more miserable than Hardspondylosaurus.

The body length of the genus Keeluodon was only about 3.5 meters, similar to that of an average individual of the Hardospondylosaur. But Hardospondylosaur at least had sharp teeth, while Keeluodon had rounded blunt teeth, which basically meant a farewell to a feast.

Louis Dollo first believed that it fed on echinoderms, while Lingham-Soliar proposed that "small characters" such as belemnites, nautiloids, bivalves, gastropods, brachiopods, echinoderms and arthropods could all be prey for the genus Kestodon.

Tooth fossils of the genus Saurolophus (Photo by Ghedoghedo)

You may be worried about the small size of Mosasaur. But the early Mosasaurs had to go through the pain of being "small"!

Dallasaurus, also known as the Dallas lizard, mainly lived more than 90 million years ago. It was one of the most primitive mosasaurs and was semi-aquatic. It is known as the "missing link" between the terrestrial ancestors of mosasaurs and the fully aquatic mosasaurs.

Dallas Dragons (Johnson Mortimer)

Compared with later fully aquatic Mosasaurs, the humerus, radius, and ulna of Dallasaurus were still quite long, accounting for more than 50% of the forelimbs, indicating that it could still return to land activities.

The fossil of Dallasosaurus was discovered in Dallas County, Texas, USA in 2005. Judging from the few fossil materials of Dallasosaurus that have been found so far, its body length is less than 1 meter. Maybe your golden retriever can eat it as a snack...

Comparison of the size of the Dallas dragon and humans (drawn by Conty)

5. Freshwater Mosasaur: Pannoniasaurus

When talking about Mosasaur, many people immediately think of the word "sea monster", as if "Mosasaurs live in the sea" is an indisputable fact. Don't underestimate the domain of the Mosasaur family, they can still be found in fresh water.

The bizarre Pannoniasaurus inexpectatus, discovered in 1999 at a coal mine waste dump in the Bakonyi Mountains in western Hungary, is a type of mosasaur that lived in a freshwater environment.

About 85-83.5 million years ago, the area was one of the islands in the ancient Mediterranean archipelago, and freshwater rivers flowed through it, nourishing a variety of creatures including Pannoniasaurus. Pannoniasaurus is estimated to be up to 6 meters long and was likely at the top of the food chain in freshwater rivers.

Reconstruction of the skeleton of Pannoniasaurus (László Makádi, Michael W. Caldwell, Attila Ősi)

Comparison of the body size of Pannoniasaurus and humans (László Makádi, Michael W. Caldwell, Attila Ősi)

In 2012, Makádi, Caldwell and other scholars believed that so-called "freshwater mosasaurs" had been discovered in the paleontological community before, but most of those mosasaurs were not true freshwater mosasaurs, but some marine mosasaurs that seasonally "swimmed upstream" from the sea through estuaries to freshwater environments. Therefore, they were somewhat accidental, such as a Plioplatecarpus discovered in Canada in 1999.

Geochemical data from the bones of Pannoniasaurus show that it spent almost all its time in rivers, making it a true freshwater mosasaur.

The above 5 pieces of little-known knowledge may not cover your questions. You are welcome to leave a message in the comment section!

References:

[1] Mike Everhart (1999). "Mosasaurus hoffmanni-The First Discovery of a Mosasaur?". Oceans of Kansas.

[2] Florence Pieters; Peggy GW Rompen; John WM 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".

[3] Natalia B. Ananjeva (2019). "Current State of the Problems in the Phylogeny of Squamate Reptiles (Squamata, Reptilia)". Biology Bulletin Reviews.

[4] Lee, Caldwell Michael SY (2001) "Live birth in Cretaceous marine lizards (mosasauroids). " Proceedings: Biological Sciences.

[5] Daniel J. Field, Aaron Leblanc, Adrienne Gau1 AndAdam D. Behlke(2015) "Pelagic neonatal fossils support viviparity and precocial life history of Cretaceous mosasaurs." Palaeontology.

[6] Louis Dollo (1892). "Nouvelle note sur l'osteologie des mosasauriens"

[7] Russell, DA (1967). Systematics and morphology of American mosasaurs (Reptilia, Sauria).

[8] Lingham-Soliar, T. (1998). Unusual death of a Cretaceous giant. Lethaia.

[9] Johan Lindgren (2005). The first record of Hainosaurus (Reptilia: Mosasauridae) from Sweden. Journal of Paleontology.

[10] Dimitry V. Grigoriev (2014). “Giant Mosasaurus hoffmanni (Squamata, Mosasauridae) from the Late Cretaceous (Maastrichtian) of Penza, Russia”. Proceedings of the Zoological Institute RAS.

[11] Schulp, AS, Vonhof, HB, van der Lubbe, JHJL, Janssen, R., & van Baal, RR (2013). On diving and diet: resource partitioning in type-Maastrichtian mosasaurs. Netherlands Journal of Geosciences - Geologie En Mijnbouw.

[12] Cope, ED(1868).On new species of extinct reptiles. Proceedings of the Academy of Natural Sciences of Philadelphia.

[13] GL Bell, Jr.; Polcyn, MJ (2005). "Dallasaurus turneri, a new primitive mosasauroid from the Middle Turonian of Texas and comments on the phylogeny of the Mosasauridae (Squamata)." Netherlands Journal of Geoscience (Geologie en Mijnbouw)

[14] Makádi, LS; Caldwell, MW; Ősi, A. (2012). Butler, Richard J (ed.). "The First Freshwater Mosasauroid (Upper Cretaceous, Hungary) and a New Clade of Basal Mosasauroids". PLOS ONE.

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Author: Archaeology Xueqi, Master of History, Wuhan University, majoring in Shang and Zhou Dynasty archaeology

Tadpole Musical Notation original article, please indicate the source when reprinting

Editor/Xiao Xitushuo