Ichthyosaurus was a genus of ichthyosaur. Ichthyosaurus was a small variety of ichthyosaur, only reaching 2 meters (6.6 feet). They lived during the Late Triassic period to the Early Jurassic Period and ate small fish, squids, and other water-dwelling creatures. Ichthyosaurus lived in the seas that covered modern-day England. It was the first Jurassic Ichthyosaur. It is among the best known ichthyosaur genera, with the Order Ichthyosauria being named after it.[1][2][3]Ichthyosaurus was the first complete fossil to be discovered in the early 1800's by Mary Anning in England.
History[]
Cast of the first known complete Ichthyosaurus specimen (originally referred to as Proteosaurus), which was destroyed during WW2
Ichthyosaurus was first discovered by the first paleontologist; Mary Anning. As the story goes, Anning was walking along the beach, when she found a relatively complete, articulated Ichthyosaurus skeleton. She reported the find to the local museum and it was recognized as a new species, and named Ichthyosaurus communis. Since then, five new species of Ichthyosaurus have been named, one of which, I. anningae, was named after Anning.
From a discoverer who was most certainly Mary Anning, a fossil from Lyme Regis in 1818 was taken by Thomas James Birch, a collector who had acquired the specimen. Birch then sold it the Royal College of Surgeons in 1820 to raise funds for the Anning family, who were having difficulties paying rent. At this time, paleontology had been in its early years, and so scholars disagreed on its identity. This specimen was the most complete known at the time, and Everard Home published his findings in 1819, with the name Proteosaurus being coined. In May 1941, the college was struck during a German air raid and the specimen was destroyed, with only a single illustration remaining by William Clift. In 2016, Dean Lomax and Judy Massare discovered aged casts within the collections at the Peabody Museum. They soon identified the cast as having been made of the lost specimen, but discovered no records of it ever being produced. The staff has assumed that it was a genuine fossil. Few details are known of it, including when Braun acquired it or who made it. In 2019, Lomax was investigating the collections of the Natural History Museum, Berlin and found another cast of the same specimen, in much better condition. Like the other, little details are known. Study published in 2022 suggests that they were made at different times, and the Yale cast may have been made before Birch had sold the fossil. In the original illustration, they identified several missing bones and other errors. They were able to confirm placement in Ichthyosaurus, but not enough diagnostic features could assign a species. This research was published in the same journal it had originally been published in.
Description[]
Size comparison
Ichthyosaurus was smaller than most of its relatives, measuring 2 meters (6.6 feet) in length. Hundreds of well-preserved, fossilized skeletons have been found in Jurassic rock at Holzmaden, Germany. Some of the bones were still articulated. Some fossils still had baby specimens inside them, indicating that Ichthyosaurus was viviparous. Similar finds in the related Stenopterygius also show this. The German fossils also featured the outline of Ichthyosaurus's skin, revealing that it had a fleshy dorsal fin on its back and a large caudal fin. Other ichthyosaur fossils showed this feature was not limited to Ichthyosaurus.
One may mistake Ichthyosaurus as the Jurassic equivalent of a bluefin tuna: this marine reptile had an amazingly fishlike shape, with a streamlined body, a finlike structure on its back, and a hydrodynamic, two-pronged tail.
As you may have guessed from its name, Ichthyosaurus has lent its name to an important family of marine reptiles, the Ichthyosaurus, which descended from terrestrial reptiles that ventured into the water during the late Triassic period. Before they faded from the scene (supplanted by better adapted plesiosaurs and pliosaurs), in the late Jurassic period, the ichthyosaurs produced some truly massive genera, most notably the 30-foot-long, 50-ton Shonisaurus.
Classification[]
Life restoration of I. communis
Skeleton of I. breviceps
Laboury et al. (2022) find:
| Ichthyosauridae |
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Paleobiology[]
Restoration of three I. anningae
Ichthyosaurus ear bones were solid, probably transferring water vibrations to the inner ear. Still, hunting by sight was the creature's main feeding activity; it had huge, sensitive eyes, protected by bony shields. Coprolites of Ichthyosaurus reveal that its diet consisted of fish and squid. It was initially believed that Ichthyosaurus laid eggs on land, but fossil evidence shows that in fact the females gave birth to live young. As such, they were well-adapted to life as fully pelagic organisms (i.e. they never came onto land). The babies were born tail first to prevent them from drowning in the water.
Senses[]
Ichthyosaurus bears solid ear bones, which means that the animal was well adapted for detecting movement through water vibrations. The eyes were massive, with a large sclerotic ring sitting in the orbits to keep their eyes from bursting in deep water. Ichthyosaurus was likely a more visually-oriented hunter, since their eyes were so delicate and huge. Ichthyosaurus had among the largest eyes of any extinct or extant vertebrate.
Diet[]
Ichthyosaurus is also known from coprolites, which reveal that Ichthyosaurus ate large amounts of fish and squid. Ichthyosaurus hunted in groups, swimming into large shoals of schooling fish. Their jaws are built to pierce the flesh of their food, holding them in place.
Birthing[]
Well preserved fossils show that Ichthyosaurus birthed their young live, and that they were ready to start basic life functions from the get-go. Their children were fully pelagic, relying only on their mothers, and were born tail first to prevent drowning. It was initially thought that Ichthyosaurus climbed onto land to lay eggs, but it has since been proven false. At no point in their lives did Ichthyosaurus climb onto land.
Paleoecology[]
Ichthyosaurus lived during the Early Jurassic period, around 200 million years ago, with a possible yet unconfirmed record of also living during the Triassic period. Fossils have been found mainly in Europe; including the British Isles, Germany, Belgium and Switzerland. A species has also been found in Indonesia. It shared its environment with Early Jurassic plesiosaurs, such as Plesiosaurus and Attenborosaurus. It primarily fed on fish and squid, which it used its large eyes and attuned hearing to locate.[4]
Appearance in other media[]
Jurassic Park[]
- Ichthyosaurus appeared in Jurassic Park arcade.
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Read more Ichthyosaurus on Jurassic Park Wiki |
References[]
- https://en.wikipedia.org/wiki/Ichthyosaurus
- https://scitechdaily.com/scientists-discover-fish-like-marine-reptile-buried-in-its-own-blubber-150-million-years-ago/
- https://www.britannica.com/animal/ichthyosaur
- https://kids.britannica.com/kids/article/Ichthyosaurus/390067
- https://www.thoughtco.com/ichthyosaurus-1091502
- https://ucmp.berkeley.edu/diapsids/ichthyosauria.html
- https://www.mindat.org/taxon-7682338.html
- https://kidadl.com/dinosaur-facts/ichthyosaurus-facts
- https://oumnh.ox.ac.uk/learn-mary-annings-ichthyosaur
- https://www.livescience.com/43344-ichthyosaur-fossil-live-birth-found.html
- https://www.newscientist.com/article/dn26975-stunning-fossils-mother-giving-birth/
- ↑ Maisch MW, Matzke AT. 2000. The Ichthyosauria. Stuttgarter Beiträge zur Naturkunde Serie B (Geologie und Paläontologie) 298: 1-159
- ↑ McGowan C, Motani R. 2003. Ichthyopterygia. – In: Sues, H.-D. (ed.): Handbook of Paleoherpetology, Part 8, Verlag Dr. Friedrich Pfeil, 175 pp., 101 figs., 19 plts; München
- ↑ Maisch MW, Reisdorf AG, Schlatter R, Wetzel A. 2008. A large skull of Ichthyosaurus (Reptilia: Ichthyosauria) from the Lower Sinemurian (Lower Jurassic) of Frick (NW Switzerland). Swiss Journal of Geosciences 101: 617-627.
- ↑ Ichthyosaurus. Prehistoric Wildlife. Retrieved October 14, 2022.