Pubblicazione scientifica

Exceptionally prolonged tooth formation in elasmosaurid plesiosaurians

FILONE TECNOLOGICO	TEMA
produzione e cattura

RIASSUNTO

Elasmosaurid plesiosaurians were globally prolific marine reptiles that dominated the Mesozoic seas for over 70 million years. Their iconic body-plan incorporated an exceedingly long neck and small skull equipped with prominent intermeshing ‘fangs’. How this bizarre dental apparatus was employed in feeding is uncertain, but fossilized gut contents indicate a diverse diet of small pelagic vertebrates, cephalopods and epifaunal benthos. Here we report the first plesiosaurian tooth formation rates as a mechanism for servicing the functional dentition. Multiple dentine thin sections were taken through isolated elasmosaurid teeth from the Upper Cretaceous of Sweden. These specimens revealed an average of 950 daily incremental lines of von Ebner, and infer a remarkably protracted tooth formation cycle of about 2–3 years–other polyphyodont amniotes normally take ~1–2 years to form their teeth. Such delayed odontogenesis might reflect differences in crown length and function within an originally uneven tooth array. Indeed, slower replacement periodicity has been found to distinguish larger caniniform teeth in macrophagous pliosaurid plesiosaurians. However, the archetypal sauropterygian dental replacement system likely also imposed constraints via segregation of the developing tooth germs within discrete bony crypts; these partly resorbed to allow maturation of the replacement teeth within the primary alveoli after displacement of the functional crowns. Prolonged dental formation has otherwise been linked to tooth robustness and adaption for vigorous food processing. Conversely, elasmosaurids possessed narrow crowns with an elongate profile that denotes structural fragility. Their apparent predilection for easily subdued prey could thus have minimized this potential for damage, and was perhaps coupled with selective feeding strategies that ecologically optimized elasmosaurids towards more delicate middle trophic level aquatic predation.

DATA

Data di pubblicazione: 27/02/2017

AUTORI

KEAR BENJAMIN P
LARSSON DENNIS
LINDGREN JOHAN
KUNDRAT MARTIN

ENTE DI AFFERENZA

MUSEUM OF EVOLUTION UPPSALA UNIV UPPSALA SWEDEN
DEPT ORGANISMAL BIOLOGY UPPSALA UNIV UPPSALA SWEDEN
DEPT GEOLOGY LUND UNIV LUND SWEDEN
CTR INTERDISCIPLINARY BIOSCIENCES FACULTY OF SCIENCE UNIV PAVOL JOZEF SAFARIK JESENNA 5 SK KOSICE SLOVAK REPUBLIC
UNIV MICHIGAN US

RIVISTA

PLoS ONE, 12(2), e0172759

IMPACT FACTOR

2,870

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