A hunt gone unsuitable! Inventive reconstruction of Otodus megalodon feeding upon an historic swordfish ~11 – 3.7 million years in the past. A puncture damage to the tooth gum comparable to this will have brought about gemination of the growing tooth buds. Credit score: Jorge Gonzalez
Did the world’s largest prehistoric shark want an orthodontist, or did it simply have a foul lunch?
Researchers from North Carolina State College (NCSU) and the North Carolina Museum of Pure Sciences examined a deformed tooth from an Otodus megalodon shark to find out the foundation trigger: was it developmental, or associated to feeding? The findings may give paleontologists extra perception into the developmental processes related to tooth damage in historic sharks, in addition to feeding conduct.
At difficulty is an abnormality known as double tooth pathology, wherein a single tooth seems “break up.” There are a number of attainable causes: throughout tooth improvement two tooth buds can fuse into one or one tooth bud can break up into two (a course of referred to as gemination). Fusion and gemination and fusion could be brought on by illness, genetics, or bodily damage to the tooth bud.
“We don’t have lots of knowledge on double tooth pathologies in historic shark species,” says Harrison Miller, former NC State undergraduate scholar and corresponding creator of a paper describing the work. “So this was a possibility to fill in these gaps – and maybe be taught extra concerning the sharks within the course of.”
The researchers examined three irregular enamel: one 4-inch tooth from O. megalodon, an apex predator the dimensions of a college bus that dominated the seas within the Miocene and early Pliocene durations (from 11 to three.7 million years in the past); and two from Carcharhinus leucas, a a lot smaller bull shark species that lived throughout the identical interval and nonetheless roams the seas at present.
Regular versus deformed O. megalodon and C. leucas enamel. Credit score: Matthew Zeher
All three oddly-shaped enamel displayed a type of double tooth pathology. The researchers in contrast the enamel to regular enamel from each species and carried out nano-CT imaging of the deformed enamel in order that they may study what was happening inside.
Whereas the pathological enamel did have extra inside canals than regular enamel – confirming both the unfinished splitting or becoming a member of of two enamel throughout improvement – the researchers have been unable to definitively set up a developmental trigger.
“A part of the problem was in making use of terminology from work in people and different mammals to sharks,” says Haviv Avrahami, NC State doctoral scholar and paper co-author.
“Sharks have cartilaginous skeletons, not boney skeletons, so preservation of their jaws is uncommon within the fossil file, and normally, we solely discover the person remoted enamel. Moreover, sharks have totally different mechanisms for tooth improvement – they've steady tooth alternative, so you possibly can’t have a look at what is going on in the remainder of the jaw to rule out fusion or gemination.”
Given what the researchers find out about this type of pathology in trendy shark enamel, nonetheless, they lean towards feeding-related damage as a extra possible trigger.
“With O. megalodon specifically, the present understanding is that they fed totally on whales,” Avrahami says. “However we all know that tooth deformities in trendy sharks could be brought on by one thing sharp piercing the conveyor belt of growing enamel contained in the mouth. Primarily based on what we see in trendy sharks, the damage was probably brought on by chomping down on a spiny fish or taking a nasty stab from a stingray barb.”
“We additionally know that O. megalodon had nesting grounds round Panama, and that family of contemporary stingray species additionally inhabited that space,” Harrison says. “And these spines can get very thick. So a tooth damage of this kind may point out that O. megalodon was extra of a generalist predator – and that this O. megalodon specifically simply had a foul day.”
Lindsay Zanno, head of paleontology on the N.C. Museum of Pure Sciences, affiliate analysis professor at NC State and co-author of the analysis, agrees.
“After we consider predator-prey encounters, we have a tendency to order our sympathy for the prey, however the lifetime of a predator, even a big megatooth shark, was no cakewalk both.”
The work seems within the journal PeerJ, and was made attainable by Mark Kostich’s donation of the pathological O. megalodon tooth (NCSM 33639) to the Paleontological Collections of the N.C. Museum of Pure Sciences.
“We’re extremely grateful to Mark for gifting this specimen to the museum so we may be taught extra about these historic animals,” Zanno says. “So many vital fossils are hidden away in non-public collections, the place they're unable to shed new mild on our wondrous world.”
Reference: “Dental pathologies in lamniform and carcharhiniform sharks with feedback on the classification and homology of double tooth pathologies in vertebrates” by Harrison S. Miller?, Haviv M. Avrahami and Lindsay E. Zanno, 11 Could 2022, PeerJ.
DOI: 10.7717/peerj.12775
Post a Comment