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- Tooth types of the sand tiger shark, Carcharias taurus . Ua: upper anterior; I: intermediate; Ul: upper lateral; S: symphyseal; La: lower anterior; Ll: lower lateral. Tooth nomenclature modified from Applegate (1965); illustration modified from Compagno (1984). Not to scale. 

- Tooth types of the sand tiger shark, Carcharias taurus . Ua: upper anterior; I: intermediate; Ul: upper lateral; S: symphyseal; La: lower anterior; Ll: lower lateral. Tooth nomenclature modified from Applegate (1965); illustration modified from Compagno (1984). Not to scale. 

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Differences in insertion angles of each tooth type of Carcharias taurus are described and analyzed within a functional framework. Upper anterior teeth show a more pronounced inward inclination than upper lateral and lower anterior ones that would be related to initial puncturing of prey. Lower anterior teeth have an outward inclination, probably re...

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Context 1
... studies have shown the relationship between tooth shape and function in elasmobranchs. Piscivorous forms have narrow and long teeth, while species that prey on marine mammals and reptiles have large, serrated teeth. Elasmobranchs that feed on crabs, molluscs and other hard-shelled organisms have pavement-like dentitions (Budker, 1971; Lagler et al. , 1977; Cailliet et al. , 1986; Tricas et al. , 1997). However, these generalisations have some exceptions. For example the narrownose smoothhound shark, Mustelus schmitti (Carcharhiniformes), has a pavement-like dentition but fish is an important prey item of its diet (Menni et al. , 1986). Teeth with different shape and/or size play different roles during prey catching and handling in elasmobranchs (Applegate, 1965). For instance, in species with heterodonty such as the horn sharks Heterodontus spp. (Heterodontiformes) and the bonnethead shark Sphyrna tiburo (Carcharhiniformes), anterior teeth are sharp and efficient in grasping food, while posterior teeth are molariform and crush the food (Tricas et al. , 1997). Some authors have also acknowledged the importance of Dental Insertion Angles (DIA), an angle between the long axis of a jaw and the axis of a tooth, in elasmobranchs. For example, Frazzetta (1988) studied the biomechanics of serrated and smooth-edged shark teeth and found a relationship between the DIA and the cutting capability of teeth. Kajiura and Tricas (1996) described a reproduc- tion-linked seasonal change of DIA in the Atlantic stingray, Dasyatis sabina (Rajiformes). The sand tiger shark, Carcharias taurus , is a common shark found in warm temperate coastal waters of both sides of the Atlantic, Mediterranean, Red Sea, western Indian Ocean, western Pacific, and southern Australia (Compagno, 1984; Last and Stevens, 1994). It feeds primarily on small to medium-sized fishes (Compagno, 1984; Sauer and Smale, 1991; Lucifora et al. , 1999). The dentition of the sand tiger shark consists mainly of narrow, long, and large teeth well suited for prey grasping (Bigelow and Schroeder, 1948; Springer, 1961). The aims of this paper are: (1) to describe and quantitatively analyse DIAs of the sand tiger shark; (2) to compare our functional interpretations of DIA analysis with the previously published hypothesis of differential use of teeth based on tooth shape (Applegate, 1965); and (3) to describe some dental anomalies (= deformed teeth) in C. taurus . For practical purposes, we use a tooth type nomenclature similar to that proposed by Applegate (1965) (Fig. 1), although it may not reflect homologies among teeth of different species (Shimada, 1999). In this study we examined 15 randomly sampled jaw specimens of Carcharias taurus from the Province of Buenos Aires coast (~ 36°S to ~ 41°S, Argentina); samples are kept by the senior author. The jaws were obtained from commercial fishermen and they were already excised from the shark when available to us. Then, size of sharks could not be measured. However, crown height of the second lower anterior tooth (La2) ranged from 15.5 to 29 mm, which corresponds to sharks measuring between 143 and 281 cm in total length (TL), according to the regression equation presented by Shimada (1999) (i.e., TL (cm) = 10.189 x La2 (mm) - 14.28). All measurements were taken from the left side. The DIA for each tooth were defined as the angle between the long axis parallel to the ventral border of the palatoquadrate and an imaginary line running through the tip of the tooth and the midpoint of the tooth base (Fig. 2). DIAs were measured with a pair of compasses and translated to paper by imposing the compasses on the paper and drawing a short line on the compasses’arms. The DIA was completely drawn by continuing and intercepting the lines on the paper. A right-angled triangle ...
Context 2
... practical purposes, we use a tooth type nomenclature similar to that proposed by Applegate (1965) (Fig.1), although it may not reflect homologies among teeth of different species (Shimada, 1999). ...
Context 3
... null and alternative hypotheses see text. For abbreviations see figure 1. ...

Citations

... Species with long, pointed teeth, like the sandtiger shark, use their teeth to quickly grab and swallow smaller prey (e.g. Lucifora, 2001;Ferrara et al., 2011). Some shark species like the nurse shark have conical or flattened teeth for crushing crustaceans or molluscs. ...
Article
Sharks are apex-predators that play an important role in past and present aquatic food webs. However, their diet - especially in extinct species - is often not well constrained. Dental microwear texture analysis (DMTA) has been successfully applied to reconstruct diet and feeding behaviours of different aquatic and terrestrial vertebrates. However, unlike in mammals, food-to-tooth contact in sharks is rather limited because only larger prey is manipulated before swallowing. Together with a fast tooth replacement rate, this reduces wear on individual teeth. Here, we present an explorative study of dental microwear texture on extant and extinct sharks to test whether ante-mortem wear is related to ingested diet or habitat preferences and resistant to post-mortem alteration processes. Shark teeth from 24 modern species and 12 fossil species from different localities were measured. As an additional comparison, extant shark teeth of Carcharhinus plumbeus were tumbled in sediment-water suspensions to simulate post-mortem mechanical alteration by sediment transport. Only three of the twelve extant shark species with three or more specimens had significantly different dental surface textures. Furthermore, no clear relation between food or habitat preferences and ante-mortem dental wear features was detected for this sample set. Tumbling modern shark teeth with siliciclastic sediment of four different grain size fractions led to increasing complexity of the dental surface. Fossil specimens resemble these experimentally altered shark teeth more in complexity and roughness. Thus, fossil shark teeth seem to display either very different (e.g. harder) diet-related wear or a strong degree of post-mortem alteration. Based on our restricted sample size, dental wear of shark teeth does overall not seem to simply reflect dietary differences; hence, it is difficult to use DMTA as reliable dietary reconstruction, in either extant nor extinct sharks.
... Most macrophageous lamniformes possess narrow and awl-shaped smoothedged teeth arranged in independent files on multiple functional rows (Shimada, 2002 and present study). The lamnoid upper anterior dentition particularly, once the jaws pronated, is optimized to grasp and hook prey items, preventing them to escape prior to be swallowed in whole (Lucifora et al., 2001). Scott (2016) depicts a cycle of pronation and supination of the mandibular arch in an Orectolobiformes: the white-spotted bamboo shark, Chiloscyllium plagiosum (Bennett, 1830). ...
Article
The anatomy of the feeding apparatus of the snaggletooth shark, Hemipristis elongata (Klunzinger, 1871) is illustrated in detail from the dissection of three heads. Two new muscles are described: the Adductor mandibularis internus and the Levator mandibularis. A subdivision of the Levator palatoquadrati is described and named the Pronator subdivision of the Levator palatoquadrati. Also, eight new anatomical features associated with the mandibular arch and with the chondrocranium (CR) are described. Three are cartilages: the suprapalatine cartilages, the craniopalatoquadrate cartilage and the calcified Meckelian dental fold. The remaining five features are processes: the Pronator process of the palatoquadrate (PQ), the Levator palatoquadrati alpha process, the proquadrate process, the ectorbital process (ECP) and the Meckelian Intermandibularis ridge. Some of them are not restricted to H. elongata. The function of these new muscles and anatomical features is discussed and a hypothesis about the functional morphology of the feeding apparatus of the snaggletooth shark is proposed. The extent and the assumptive importance of the pronation of the mandibular arch in the snaggletooth shark feeding behaviour is described and discussed. An alternative for the main function of the Levator palatoquadrati as hypothesized by Motta et al. (1997) and Wilga et al. (2001) is proposed for the families Hemigaleidae, Carcharhinidae and Sphyrnidae. We anticipate this muscle is more involved in the pronation rather than in the protrusion of the mandibular arch.
... Depending on the type of the prey to be consumed, dental morphology of sharks exhibits remarkable variations, and the relationship between tooth shape and function in sharks has shown by several studies (e.g. Huber et al. 2009;Lucifora et al. 2001). Speaking honestly, blade-like, razor-sharp tooth is the unforgettable focal point of predatory shark idea. ...
... The teeth were not clustered into classically used tooth-type denominations (e.g., symphyseal, parasymphyseal, lateral, commissural) (Reif, 1976;Lucifora et al., 2001) on purpose since we did not visually identify abrupt tooth shape or size change along the mesio-distal axis, TA B L E 1 Scanned Scyliorhinus stellaris specimens. except for the symphyseal teeth on the lower jaw ( Figure 1a). ...
Article
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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 .
... Spontaneous tooth loss does not, however, preclude shearing forces between tooth and food as a source of tooth loss, which may also account for many of the tooth loss occurrences we observed. Lucifora et al. (2001) examined shearing forces between food and teeth in C. taurus and concluded that these forces are not consistent across the rami of the jaw. Additionally, our observations of teeth encountering food during compressive jaw protrusion (Figure 4) or stepwise jaw retraction ( Figure 5) indicate that piercing teeth do not always encounter the prey orthogonally. ...
Article
This study examines the feeding behaviour and kinematics of three sub‐adult sand tiger sharks Carcharias taurus on display at Mystic Aquarium (Mystic, Connecticut, USA). Using high‐speed video data from 52 bites, we identify kinematic variables associated with the expansive and compressive phases of the bite. The mean bite duration from the onset of the expansive phase to the conclusion of the compressive phase is mean (± SD) 0.14 ± 0.01 s and across the ten fastest bites of each individual, the maximum performance average is 0.13 ± 0.01 s. Values of maximum performance do not vary significantly among individuals. When compared with kinematic bite data from species studied previously, these results indicate that body size is not the only determinant factor of bite duration. This study also provides detailed descriptions of feeding behaviours in C. taurus and presents documentation of tooth loss both prior to and during feeding, suggesting that there are multiple mechanisms of tooth loss and use in C. taurus. Finally, we discuss the behavioural and ecological components of prey capture in C. taurus and suggest points of consideration to facilitate interspecific comparisons of prey capture performance in ram‐feeding macrophagous elasmobranchs. This article is protected by copyright. All rights reserved.
... In many large-bodied sharks, the differentiation in tooth morphology between the upper and lower jaws as well as along the tooth row (the mesio-distal direction parallel to the jaw margin; Bigelow & Schroeder, 1953b;Cappetta, 1987) has been hypothesized to differ in function during prey capture, retention, and processing (Applegate, 1965;Frazzetta, 1988;Liem et al., 2001;Lucifora, Menni, & Escalante, 2001). In carcharhiniform sharks, anterior teeth on the lower jaw are typically gracile, smooth-edged, and often make first contact with prey items during jaw closure. ...
Article
Tooth morphology is often used to inform the feeding ecology of an organism as these structures are important to procure and process dietary resources. In sharks, differences in morphology may facilitate the capture and handling of prey with different physical properties. However, few studies have investigated differences in tooth morphology over ontogeny, throughout the jaws of a single species, or among species at multiple tooth positions. Bull (Carcharhinus leucas), blacktip (Carcharhinus limbatus), and bonnethead sharks (Sphyrna tiburo) are coastal predators that exhibit ontogenetic dietary shifts, but differ in their feeding ecologies. This study measured tooth morphology at six positions along the upper and lower jaws of each species using elliptic Fourier analysis to make comparisons within and among species over their ontogeny. Significant ontogenetic differences were detected at four of the six tooth positions in bull sharks, but only the posterior position on the lower jaw appeared to exhibit a functionally relevant shift in morphology. No ontogenetic changes in morphology were detected in blacktip or bonnethead sharks. Intraspecific comparisons found that most tooth positions significantly differed from one another across all species, but heterodonty was greatest in bull sharks. Additionally, interspecific comparisons found differences among all species at each tooth position except between bull and blacktip sharks at two positions. These morphological patterns within and among species may have implications for prey handling efficiency, as well as in providing insight for paleoichthyology studies and reevaluating heterodonty in sharks. Ontogenetic changes in morphology are limited in bull sharks and do not occur in blacktip and bonnethead sharks. Heterodonty is ubiquitous within the jaws of each species. Significant interspecific differences were found at all six tooth positions.
... Compared to most shark species the upper and lower jaws of the sandtiger shark are comprised of several active rows of slender teeth, primarily used for puncturing and grasping fish, but not for gouging (Fig 2) (16,17). To that extent, their more labially inclined upper anterior teeth are most suited for puncture, while the more lingually inclined lower anterior teeth are more adapted to grasping (16,18). ...
... Compared to most shark species the upper and lower jaws of the sandtiger shark are comprised of several active rows of slender teeth, primarily used for puncturing and grasping fish, but not for gouging (Fig 2) (16,17). To that extent, their more labially inclined upper anterior teeth are most suited for puncture, while the more lingually inclined lower anterior teeth are more adapted to grasping (16,18). As a consequence of the characteristics and position of these teeth, the victim ended up with numerous differently shaped but mainly superficial lacerations of various dimensions along her right medial leg where two rather distinct bites could be identified. ...
Article
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The mouth of a shark is a breeding ground for a large variety of bacteria which can easily get transferred onto a human body in the event of a shark bite. Here, we review infections originating from shark oral bacterial flora, which originate from the microbiome of its prey, as well as from the surroundings where an incident takes place. We use the example of an incident which occurred in an aquarium involving a sandtiger shark, Carcharias taurus. In addition to a succinct analysis and interpretation of the wound and recovery process, an overview of currently known bacteria associated with shark bite wounds is given, as well as a summary of the effects of various previously tested antibiotics on bacteria derived from blacktip sharks, Carcharhinus limbatus, bull sharks, C. leucas, and tiger sharks, Galeocerdo cuvier. Level of evidence: Therapeutic study, level V.
... Figure 1 shows the entire disconnection of an a1 within 0.3 seconds. White sharks belong to those species where more than one row of lower teeth is active, with prominent differences in insertion angles, the angle between axis of a tooth and main axis of the jaw [27]. ...
... Research on the functional morphology of feeding in sharks has typically focused on the kinematics and mechanics of cranial movement (Ferry-Graham, 1998;Wilga et al., 2001;Motta, 2004;Huber et al., 2005;Motta et al., 2008), often neglecting to integrate the function of teeth (but see Ramsay & Wilga, 2007;Dean et al., 2008;Whitenack et al., 2011). While some studies have examined the design and performance of shark teeth during puncture and draw (Frazzetta, 1988;Lucifora et al., 2001;Whitenack & Motta, 2010;Whitenack et al., 2011;Corn et al., 2016), a further exploration in the complexity of shark tooth structure is essential in elucidating the biological role that teeth play in feeding and particularly during successful prey capture. ...
... N . B E R G M A N E T A L. from large, soft-prey items, whereas the long, pointed teeth in the sand tiger shark Carcharias taurus Rafinesque 1810 exemplify a piscivorous diet that pierce and grasp fast moving fishes (Frazzetta, 1988;Lucifora et al., 2001;Smale, 2005;Ferrara et al., 2011). Dentitions may also be suited to the stress experienced during feeding: long, pointed teeth for soft-bodied and slippery prey, contrasted to broad, serrated teeth for hard, dense prey (Frazzetta, 1988;Whitenack & Motta, 2010;. ...
Article
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This study examined the minimum force required of functional teeth and replacement teeth in the tiger shark Galeocerdo cuvier and the sandbar shark Carcharhinus plumbeus to penetrate the scales and muscle of sheepshead Archosargus probatocephalus and pigfish Orthopristis chrysoptera. Penetration force ranged from 7·7-41·9 and 3·2-26·3 N to penetrate A. probatocephalus and O. chrysoptera, respectively. Replacement teeth required significantly less force to penetrate O. chrysoptera for both shark species, most probably due to microscopic wear of the tooth surfaces supporting the theory shark teeth are replaced regularly to ensure sharp teeth that are efficient for prey capture.
... Most Danian teeth occupy a very similar morphospace to teeth of juvenile C. taurus. One major shift during ontogeny is that adult C. taurus consume more benthic elasmobranchs such as batoids [37]. We infer that Danian lamniform sharks probably also consumed a wide range of small-sized, demersal prey as noted above, but probably not batoids and other benthic elasmobranchs. ...
Article
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Lamniform sharks are apex marine predators undergoing dramatic local and regional decline worldwide, with consequences for marine ecosystems that are difficult to predict. Through their long history, lamniform sharks have faced widespread extinction, and understanding those ‘natural experiments’ may help constrain predictions, placing the current crisis in evolutionary context. Here we show, using novel morphometric analyses of fossil shark teeth, that the end-Cretaceous extinction of many sharks had major ecological consequences. Post-extinction ecosystems supported lower diversity and disparity of lamniforms, and were dominated by significantly smaller sharks with slimmer, smoother and less robust teeth. Tooth shape is intimately associated with ecology, feeding and prey type, and by integrating data from extant sharks we show that latest Cretaceous sharks occupied similar niches to modern lamniforms, implying similar ecosystem structure and function. By comparison, species in the depauperate post-extinction community occupied niches most similar to those of juvenile sand tigers (Carcharias taurus). Our data show that quantitative tooth morphometrics can distinguish lamniform sharks due to dietary differences, providing critical insights into ecological consequences of past extinction episodes.