Kronosaurus (meaning "Lizard of Kronos") is a potentially dubious[1] genus of large carnivorous marine reptile that belong to the order of Plesiosauria and the suborder of Pliosauroidea.[2]
Kronosaurus lived during the early Cretaceous Period and was one of the largest genus of pliosaur, reaching about 9–10 meters in total body length. Kronosaurus was probably one of the top under-sea predators of its time.
The genus specimens have reassigned into new categories Eiectus and Monquirasaurus.
Its diet consisted predominantly of fish and other under sea creatures, including marine dinosaurs and other marine reptiles. Kronosaurus had a head the size of an average human.
Discovery[]
QM F1609, the holotype mandibular symphysis of K. queenslandicus
In 1899, Andrew Crombie of Hughenden discovered a "scrap of bone" containing six conical teeth, and gave this fragmentary fossil to the Queensland Museum. Twenty-five years later, then-director Heber Longman formally described the specimen as the holotype of a new species: Kronosaurus queenslandicus. More Kronosaurus material, including a partial skull, was discovered in 1929, in the same location as Crombie's original find.
In 1977, a Colombian peasant farmer from Moniquirá turned up an enormous stone while tilling his field, which he later recognized as a possible fossil. Excavation revealed a nearly complete Kronosaurus skeleton, one of the best preserved fossils to come from Colombia. Oliver Hampe formally described the specimen in 1992, assigning it to a second species, K. boyacensis.
The people of Villa de Leyva built a museum, El Fósil, around the spot where the skeleton was excavated, and the K. boyacensis skeleton is on display there.
In 2021, "K." boyacensis was transferred to its own genus, Monquirasaurus.
Harvard's completed skeleton[]
MCZ 1285, the Harvard skeleton historically attributed to Kronosaurus, sometimes nicknamed "Plasterosaurus". This specimen would have been reconstructed with too many vertebrae and with wrong cranial proportions
In 1931 the Harvard Museum of Comparative Zoology (MCZ) sent an expedition to Australia for the dual purpose of procuring specimens – the museum being "weak in Australian animals and...desires[ing] to complete its series" – and to engage in "the study of the animals of the region when alive." The Harvard Australian Expedition (1931–1932), as it became known, was a six-man venture led by Harvard Professor William Morton Wheeler, with the others being Dr. P. Jackson Darlington Jr. (a renowned coleopterist), Dr. Glover Morrill Allen and his student Ralph Nicholson Ellis, medical officer Dr. Ira M. Dixon, and William E. Schevill (a graduate-student in his twenties and Associate Curator of Invertebrate Palaeontology). MCZ director Thomas Barbour said at the time "We shall hope for specimens' of the kangaroo, the wombat, the Tasmanian devil and Tasmanian wolf," and the mission was a success with over 300 mammal and thousands of insect specimens returning to the United States. Yet Mr. Schevill, the team's fossil enthusiast, remained in Australia after the others had departed and, in the winter of 1932, was told by the rancher R.W.H. Thomas of rocks with something "odd" poking out of them on his property near Hughenden. The rocks were limestone nodules containing the most complete skeleton of Kronosaurus ever discovered. After dynamiting the nodules out of the ground (and into smaller pieces weighing approximately four tons) with the aid of a British migrant trained in the use of explosives, William Schevill had the fossils shipped back to Harvard for examination and preparation. The skull—which matched the holotype jaw fragment of K. queenslandicus—was prepared right away, but time and budget constraints put off restoration of the nearly complete skeleton – most of the bones of which remained unexcavated within the limestone blocks – for 20 years.
Description[]
The genus was named after the most powerful Titan in Greek Mythology, Kronos.
The fossils of smaller plesiosaurs strongly suggests that Kronosaurus and its relatives may have preyed upon smaller plesiosaur species. This massive marine reptile was the biggest and baddest marine predator of the large inland sea that covered western Queensland in the Cretaceous. It used teeth the size of bananas to feast on ichthyosaurs, other plesiosaurs, turtles and fish. Kronosaurus has special air chambers on its snout that are used to scent prey in the same way as a pair of ears work, pinpointing exactly where a smell is coming from.
Kronosaurus lived in the Early Cretaceous Period (Aptian-Albian). The holotype specimen of the species K. queenslandicus was described by Longman in 1924, and is currently in the Queensland Museum. Hampe described a second species, K. boyacensis, in 1992 from Colombia. A preserved K. boyacensis can be seen in Villa de Leiva Boyaca, Columbia..
In more recent analysis, it has been said that all the non-holotype specimens of Kronosaurus have been put into different species and that the holotype should be restricted as the only specimen. And in that paper Noe and Gomez-Perez say that even the Holotype is undiagnostic with other pliosaurs! Making Kronosaurus a dubious genus.[3]
All Sauropterygians had a modified pectoral girdle that supported a powerful swimming stroke. Kronosaurus and other plesiosaurs/pliosaurs had a similarly adapted pelvic girdle, allowing them to push hard against the water with all four flippers. Between its two limb girdles was a massive mesh of gastralia (belly ribs) that provided additional strength and support. The strength of the limb girdles, combined with evidence of large, powerful swimming muscles, indicates that Kronosaurus was likely a fast, active swimmer.
Kronosaurus queenslandicus has four pairs of premaxillary teeth. The first three pairs of its maxillary teeth are large caniniform teeth, and in its lower jaw there are also three pairs of large caniniform teeth which are located immediately in front of the three maxillary caniniforms when the mouth is closed. Two pairs of the lower jaw caniniforms occlude between the last pair of premaxillary teeth and first pair of maxillary teeth in a diastema (gap in the tooth row). The enlargement of these two pairs of lower jaw teeth in K. queenslandicus may be related to the absence of a fifth pair of premaxillary teeth, which are present in a number of other pliosaurs.
Size issues[]
Size of the largest specimen traditionally attributed to Kronosaurus (MCZ 1285) with a human. The light gray diagram represents the size of the specimen as it is currently mounted at the Museum of Comparative Zoology, while the dark gray one shows it with a more accurate estimate
Body-length estimates had previously put the total length of Kronosaurus at 12.8 meters (43 feet).[4] However, a more recent study comparing fossil specimens of Kronosaurus to other pliosaurs suggest that the previous estimate was, likely, an exaggeration, with the more accurate length estimations probably only 9-10 meters (30 33 feet).
Like other pliosaurs, Kronosaurus was a marine reptile. It had an elongated head, a short neck, a stiff body propelled by four flippers, and a relatively short tail. The posterior flippers were larger than the anterior. Kronosaurus was carnivorous, and had many long, sharp, conical teeth. A feature of the genus Kronosaurus is that the first three maxillary teeth are enlarged to fangs. Current estimates put Kronosaurus at around 9 to 10.9 meters (30 to 36 ft) in length. In 2009, K. queenslandicus was estimated to weigh about 10.6 to 12.1 metric tons (11.7 to 13.3 short tons). The skull length of Kronosaurus was estimated to be 2.21–2.85 meters (7.3–9.4 ft).
Teeth[]
The teeth of Kronosaurus are large in length (exceeding 7 centimeters - the largest up to 30 centimeters long with 12 centimeters crowns). However, they lack carinae (cutting edges) and the distinct trihedral (three facets) of Pliosaurus and Liopleurodon teeth. The combination of large size, conical shape and lack of cutting edges allows for easy identification of Kronosaurus teeth in Cretaceous deposits from Australia.[5]
Classification[]
.png){kind=link}
Skeleton of Brachauchenius, the type genus of the subfamily Brachaucheninae, a lineage of which Kronosaurus is a member
Kronosaurus belonged to the Pliosauridae family. The cladogram below follows a 2011 analysis by paleontologists Hilary F. Ketchum and Roger B. J. Benson, reduced to genera only.
| Rhomaleosauridae |
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Pliosauridae |
|
Palaeobiology[]
Restoration of Kronosaurus devouring a Woolungasaurus
Fossil stomach contents from Northern Queensland show that Kronosaurus preyed on turtles and plesiosaurs. Fossil remains of large octobrachians [34] have been found in the same area as Kronosaurus. While no direct evidence of the animal predating on these octobrachians exists they fall within the projected size range of prey Kronosaurus would potentially have pursued.[7]
Large, round bite-marks have been found on the skull of an Albian-age Australian elasmosaurid (Eromangasaurus) that could be from a Kronosaurus attack.[35][36]
Paleoecology[]
Map of the Great Artesian Basin, which is seen as the remnant of the ancient inland sea of Eromanga
Life restoration of a Kronosaurus hunting a plesiosauroid
Kronosaurus is known from remains in Australia. The area was covered by a shallow inland sea called the Eromanga Sea which Kronosaurus inhabited.[37] This environment was notably cold, experiencing near freezing temperatures [38] and seasonal ice in certain regions.[7][39]
As an apex marine predator, Kronosaurus would have predated a variety of aquatic animals. Smaller prey could have been swallowed whole, while larger prey – such as the Pacific plesiosaur Eromangasaurus – posed more of a challenge. Fossil evidence suggests that Kronosaurus tore rather than sheared off flesh, likely twisting chunks off its prey like the modern crocodile.[6]
Although the majority of specimens have been found in Australia, Kronosaurus fossils have been found as far away as Colombia. Research suggests that the genus preferred to swim in shallow waters, while analysis of the stomach contents of the near-complete skeleton showed that it fed mainly on smaller plesiosaurs, fish and squid.
Appearance in other media[]
Jurassic Park[]
- Kronosaurus appeared in Jurassic Park: Builder.
- Kronosaurus appeared in Jurassic World: The Game.
- Kronosaurus appeared in Jurassic World Evolution 2.
 |
Read more Kronosaurus on Jurassic Park Wiki |
The Land Before Time[]
It appears in The Land Before Time: Dinosaur Q&A.
 |
non-canon only |
References[]
Template:References
- ↑ https://www.sciencedirect.com/science/article/abs/pii/S0195667121003700?via%3Dihub
- ↑ https://australian.museum/learn/australia-over-time/extinct-animals/kronosaurus-queenslandicus/
- ↑ https://www.sciencedirect.com/science/article/abs/pii/S0195667121003700?via%3Dihub
- ↑ Romer AS, Lewis AD. 1959. A mounted skeleton of the giant plesiosaur Kronosaurus. Breviora 112: 1-15.
- ↑ Massare JA. 1997. Introduction - faunas, behaviour and evolution. In: Callaway JM, Nicholls EL. (Eds.), Ancient Marine Reptiles. Academic Press, San Diego, pp. 401-421.
- ↑ Kronosaurus. Prehistoric Wildlife. Retrieved October 14, 2022.