Tooth morphology and feeding ecology of early Campanian (Late Cretaceous) marine reptiles through the lens of extant odontocetes
(2022) BIOM02 20221Degree Projects in Biology
- Abstract
- Marine mammals occupy multiple trophic levels within the food webs of modern ecosystems, and secondarily aquatic reptiles played similar roles in the Mesozoic oceans. Odontocetes have conical teeth similar to those of Mesozoic marine reptiles, and thus could potentially be used to interpret the feeding ecology of the latter group. This study uses both discrete and continuous characters to determine the relationship between tooth-crown morphology and feeding ecology of extant North Sea odontocetes. From these data, the feeding habits and dietary preferences of early Campanian (Late Cretaceous) mosasaurs and plesiosaurs from the Kristianstad Basin, southernmost Sweden, are inferred. Whereas most marine reptiles and the rough-toothed dolphin... (More)
- Marine mammals occupy multiple trophic levels within the food webs of modern ecosystems, and secondarily aquatic reptiles played similar roles in the Mesozoic oceans. Odontocetes have conical teeth similar to those of Mesozoic marine reptiles, and thus could potentially be used to interpret the feeding ecology of the latter group. This study uses both discrete and continuous characters to determine the relationship between tooth-crown morphology and feeding ecology of extant North Sea odontocetes. From these data, the feeding habits and dietary preferences of early Campanian (Late Cretaceous) mosasaurs and plesiosaurs from the Kristianstad Basin, southernmost Sweden, are inferred. Whereas most marine reptiles and the rough-toothed dolphin (Steno bredanensis) have heavily ornamented and labio-lingually compressed teeth, all other odontocetes and the small-sized mosasaur Eonatator have simple, conical tooth-crowns lacking functional ornaments. The morphological convergence between teeth of Eonatator and small-sized dolphins suggests the possibility of a similar ram/pierce feeding strategy, along with a generalist diet mainly comprised of small-sized fish and cephalopods. Overall, though, mosasaurs had a unique feeding strategy that is different from that of extant large-sized macropredators, such as the killer whale and false killer whale. A few odontocete species represent viable feeding ecology analogues for Mesozoic marine reptiles despite their deeply divergent phylogenetic affinities. (Less)
- Popular Abstract
- In the Late Cretaceous (About 78 million years ago), the Kristianstad Basin was covered by a shallow sea of great wealth and was ruled by marine reptiles. The Kristianstad basins preserve an abundant and diverse assemblage of mosasaur and plesiosaur species. The marine reptiles weren’t dinosaurs, mosasaurs were giant marine lizards and plesiosaurs were a group of Sauropterygians adapted to open water, both of the two linages are flourished during Cretaceous.
Most of the marine reptiles had large body size and were predators at high trophic level. The diet of some marine reptile species could be inferred by fossil evidence, such as stomach remains and bite marks on prey items. However, these evidences are unusual, and it is still hard to... (More) - In the Late Cretaceous (About 78 million years ago), the Kristianstad Basin was covered by a shallow sea of great wealth and was ruled by marine reptiles. The Kristianstad basins preserve an abundant and diverse assemblage of mosasaur and plesiosaur species. The marine reptiles weren’t dinosaurs, mosasaurs were giant marine lizards and plesiosaurs were a group of Sauropterygians adapted to open water, both of the two linages are flourished during Cretaceous.
Most of the marine reptiles had large body size and were predators at high trophic level. The diet of some marine reptile species could be inferred by fossil evidence, such as stomach remains and bite marks on prey items. However, these evidences are unusual, and it is still hard to determine how marine reptiles capture and process the preys.
Modern marine mammals have also adapted the life underwater and play similar roles as extinct marine reptiles in the marine food webs. I noticed that the similarities between the two groups suggest marine mammals could help us infer how marine reptiles eat their preys.
Previous studies suggest animal’s feeding ecology is highly related to the tooth crowns, so I collected the data of the size, shape and structure of the tooth crowns of North Sea toothed whales and the Kristianstad Basin marine reptiles. The toothed whale species were divided into different diet and feeding ecology, and each isolated tooth crown was illustrated according to their morphology. The association of tooth crowns shows similar tooth crown morphology, diet, and feeding strategies.
The results showed that most toothed whales have simplified tooth crown lacking ornaments, such as striations and cutting edges, and most marine reptiles in this study have highly ornamented tooth crown. Nearly all of the mosasaurs have sharp cutting edges, suggest that they were macropredators and have the ability to shatter large prey items into small pieces.
While toothed whales and marine reptiles have quite different tooth crown morphology, some species still show evolutionary convergence. The tooth crowns of small-sized mosasaur Eonatator are similar with modern long-beaked dolphins, suggest that they may feed on small fish and squids, and swallow them whole. Although large-size mosasaurs are enormous macropredators parallels killer whales and false killer whales, they have highly ornamented lateral compressed tooth crown are similar to small-sized rough-toothed dolphins. This pattern indicates that large-size mosasaurs might have a unique strategy to shatter large preys by “chewing” behaviors in the rough-toothed dolphins instead of the grip and tear strategy in killer whales and false killer whales. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/9103229
- author
- Song, Yang
- supervisor
-
- Mats Eriksson LU
- Johan Lindgren LU
- organization
- course
- BIOM02 20221
- year
- 2022
- type
- H2 - Master's Degree (Two Years)
- subject
- language
- English
- id
- 9103229
- date added to LUP
- 2022-11-16 09:06:27
- date last changed
- 2022-11-16 09:06:27
@misc{9103229,
abstract = {{Marine mammals occupy multiple trophic levels within the food webs of modern ecosystems, and secondarily aquatic reptiles played similar roles in the Mesozoic oceans. Odontocetes have conical teeth similar to those of Mesozoic marine reptiles, and thus could potentially be used to interpret the feeding ecology of the latter group. This study uses both discrete and continuous characters to determine the relationship between tooth-crown morphology and feeding ecology of extant North Sea odontocetes. From these data, the feeding habits and dietary preferences of early Campanian (Late Cretaceous) mosasaurs and plesiosaurs from the Kristianstad Basin, southernmost Sweden, are inferred. Whereas most marine reptiles and the rough-toothed dolphin (Steno bredanensis) have heavily ornamented and labio-lingually compressed teeth, all other odontocetes and the small-sized mosasaur Eonatator have simple, conical tooth-crowns lacking functional ornaments. The morphological convergence between teeth of Eonatator and small-sized dolphins suggests the possibility of a similar ram/pierce feeding strategy, along with a generalist diet mainly comprised of small-sized fish and cephalopods. Overall, though, mosasaurs had a unique feeding strategy that is different from that of extant large-sized macropredators, such as the killer whale and false killer whale. A few odontocete species represent viable feeding ecology analogues for Mesozoic marine reptiles despite their deeply divergent phylogenetic affinities.}},
author = {{Song, Yang}},
language = {{eng}},
note = {{Student Paper}},
title = {{Tooth morphology and feeding ecology of early Campanian (Late Cretaceous) marine reptiles through the lens of extant odontocetes}},
year = {{2022}},
}