The intraspecific diversity of tooth morphology in the large‐spotted catshark Scyliorhinus stellaris: insights into the ontogenetic cues driving sexual dimorphism. Issue 5 (15th July 2020)

• Record Type: Journal Article
• Authors: Berio, Fidji; Evin, Allowen; Goudemand, Nicolas; Debiais‐Thibaud, Mélanie
• Is Part Of: Journal of anatomy. Volume 237:Issue 5(2020)
• Page Start: 960
• Page End: 978
• Publication Date: 2020-07-15
• Subjects: geometric morphometrics -- gynandric heterodonty -- monognathic heterodonty -- ontogenetic trajectory -- scyliorhinids; Anatomy -- Periodicals; 571.3
• DOI: 10.1111/joa.13257
• Languages: English
• ISSNs: 0021-8782

Abstract

Abstract: Teeth in sharks are shed and replaced throughout their lifetime. Morphological dental changes through ontogeny have been identified in several species and have been correlated with shifts in diet and the acquisition of sexual maturity. However, these changes were rarely quantified in detail along multiple ontogenetic stages, which makes it difficult to infer the developmental processes responsible for the observed plasticity. In this work, we use micro‐computed tomography and 3D geometric morphometrics to describe and analyze the tooth size and shape diversity across three ontogenetic stages (hatchling, juvenile, and sexually mature) in the large‐spotted catshark Scyliorhinus stellaris (Linnaeus, 1758). We first describe the intra‐individual variation of tooth form for each sex at each ontogenetic stage. We provide a tooth morphospace for palatoquadrate and Meckelian teeth and identify dental features, such as relative size and number of cusps, involved in the range of variation of the observed morphologies. We then use these shape data to draw developmental trajectories between ontogenetic stages and for each tooth position within the jaw to characterize ontogenetic patterns of sexual dimorphism. We highlight the emergence of gynandric heterodonty between the juvenile and mature ontogenetic stages, with mature females having tooth morphologies more similar to juveniles' than mature males that display regression in the number of accessory cusps. From these data, we speculate on the developmental processes that could account for such developmental plasticity in S . stellaris . Abstract : This study uncovers the wide intraspecific diversity of tooth form in the large‐spotted catshark Scyliorhinus stellaris using micro‐computed tomography and 3D geometric morphometrics. We characterize the emergence of sexual dimorphism along ontogenetic stages using sex‐specific ontogenetic trajectories. We discuss the physical and chemical parameters acting on tooth morphogenesis that may generate the described developmental plasticity in elasmobranchs.