“…The tip of the crown has a superficial flat wear facet with distinct smooth edges (Fig. 1 b, f), interpreted as an attrition wear facet 14 . Figure 1 General overview of the anterior and posterior teeth of Notocetus vanbenedeni (MPEF-PV 1120).…”
Section: Resultsmentioning
confidence: 99%
“…The tip of the main cusp has a polished wear facet with distinct microwear features (Fig. 1 c), interpreted as an abrasion wear facet 14 . The constriction zone in both Notocetus vanbenedeni teeth could represent glossowear facets 14 , but the presence and direction of surface scratches could not be assessed.…”
Section: Resultsmentioning
confidence: 99%
“…The high degree of morphological variation in teeth from early-diverging to modern odontocetes might correlate to changes in feeding strategies (e.g., 1 , 5 , 9 – 12 ). Most extant odontocetes are either suction-feeders, raptorial predators, or adopt a combination of both behaviors 11 , 13 , 14 . Osteological and soft-tissue characteristics are linked to these feeding strategies 5 , 15 , 16 , although their relationship is not always straight forward or fully understood.…”
Variations in the shape and size of teeth have been associated with changes in enamel ultrastructure across odontocetes. Characterizing these features in extinct taxa can elucidate their functional morphology and feeding strategy, while also shedding light into macroevolutionary patterns during the evolutionary history of cetaceans. This study aimed to (1) describe the enamel and dentine ultrastructure of the Early Miocene odontocetes Notocetus vanbenedeni and Phoberodon arctirostris from Patagonia (Argentina) and (2) quantify tooth and enamel ultrastructure morphological disparity among odontocetes. Enamel was predominantly prismatic, thin in the anterior tooth of N. vanbenedeni and P. arctirostris; whilst thick on the posterior tooth of N. vanbenedeni. Together with skull morphology, data suggests a raptorial feeding strategy for P. arctirostris and a combination suction feeding method for N. vanbenedeni. Statistical analyses supported these inferences, indicating that enamel characters are useful for paleoecological research. Morphological disparity analyses showed that extant odontocetes occupy a larger morphospace and have more disparate morphologies, whilst extinct odontocetes were more similar among each other than with the extant group. There was no clear phylogenetic-based grouping, suggesting that tooth and enamel ultrastructure disparity were mainly driven by ecological pressures. These results highlight enamel ultrastructure as a source for broader-scale paleoecological studies in cetaceans.
“…The tip of the crown has a superficial flat wear facet with distinct smooth edges (Fig. 1 b, f), interpreted as an attrition wear facet 14 . Figure 1 General overview of the anterior and posterior teeth of Notocetus vanbenedeni (MPEF-PV 1120).…”
Section: Resultsmentioning
confidence: 99%
“…The tip of the main cusp has a polished wear facet with distinct microwear features (Fig. 1 c), interpreted as an abrasion wear facet 14 . The constriction zone in both Notocetus vanbenedeni teeth could represent glossowear facets 14 , but the presence and direction of surface scratches could not be assessed.…”
Section: Resultsmentioning
confidence: 99%
“…The high degree of morphological variation in teeth from early-diverging to modern odontocetes might correlate to changes in feeding strategies (e.g., 1 , 5 , 9 – 12 ). Most extant odontocetes are either suction-feeders, raptorial predators, or adopt a combination of both behaviors 11 , 13 , 14 . Osteological and soft-tissue characteristics are linked to these feeding strategies 5 , 15 , 16 , although their relationship is not always straight forward or fully understood.…”
Variations in the shape and size of teeth have been associated with changes in enamel ultrastructure across odontocetes. Characterizing these features in extinct taxa can elucidate their functional morphology and feeding strategy, while also shedding light into macroevolutionary patterns during the evolutionary history of cetaceans. This study aimed to (1) describe the enamel and dentine ultrastructure of the Early Miocene odontocetes Notocetus vanbenedeni and Phoberodon arctirostris from Patagonia (Argentina) and (2) quantify tooth and enamel ultrastructure morphological disparity among odontocetes. Enamel was predominantly prismatic, thin in the anterior tooth of N. vanbenedeni and P. arctirostris; whilst thick on the posterior tooth of N. vanbenedeni. Together with skull morphology, data suggests a raptorial feeding strategy for P. arctirostris and a combination suction feeding method for N. vanbenedeni. Statistical analyses supported these inferences, indicating that enamel characters are useful for paleoecological research. Morphological disparity analyses showed that extant odontocetes occupy a larger morphospace and have more disparate morphologies, whilst extinct odontocetes were more similar among each other than with the extant group. There was no clear phylogenetic-based grouping, suggesting that tooth and enamel ultrastructure disparity were mainly driven by ecological pressures. These results highlight enamel ultrastructure as a source for broader-scale paleoecological studies in cetaceans.
“…There is no attritional or occlusal wear nor any glossowear or hydrowear on the teeth of N. matakoi, suggesting it did not process abrasive prey or use their teeth to find prey in the substrate, as this would cause significant wear of the enamel [52–54]. The teeth are also too thin and gracile to be used to process large prey, as suggested for Ankylorhiza tiedemani [13].…”
All extant toothed whales (Cetacea, Odontoceti) are aquatic mammals with homodont dentitions. Fossil evidence from the late Oligocene suggests a greater diversity of tooth forms among odontocetes, including heterodont species with a variety of tooth shapes and orientations. A new fossil dolphin from the late Oligocene of New Zealand,
Nihohae matakoi
gen. et sp. nov., consisting of a near complete skull, earbones, dentition and some postcranial material, represents this diverse dentition. Several preserved teeth are horizontally procumbent, including all incisors and canines. These tusk-like teeth suggest adaptive advantages for horizontally procumbent teeth in basal dolphins. Phylogenetic analysis places
Nihohae
among the poorly constrained basal waipatiid group, many with similarly procumbent teeth. Features of
N. matakoi
such as its dorsoventrally flattened and long rostrum, long mandibular symphysis, unfused cervical vertebrae, lack of attritional or occlusal wear on the teeth and thin enamel cover suggest the rostrum and horizontally procumbent teeth were used to injure and stun prey though swift lateral head movements, a feeding mode that did not persist in extant odontocetes.
“…The level of tooth crown wear has often been used as an ecological indicator in fossil marine amniotes (e.g. Fischer et al, 2016; Fitzgerald, 2010; Ford et al, 2011; Marx et al, 2023; Massare, 1987); however, care must be taken when comparing wear patterns between marine tetrapod groups due to the different tooth replacement regimes (Armfield et al, 2013; Maxwell et al, 2012). The heaviest type of tooth wear in marine reptiles consists of oblique tooth crown breaks, which are subsequently polished (Massare, 1987).…”
Marine amniotes have played many crucial roles in ocean ecosystems since the Triassic, including predation at the highest trophic levels. One genus often placed into this guild is the large Early Jurassic neoichthyosaurian Temnodontosaurus, the only post‐Triassic ichthyosaurian known with teeth which bear a distinct cutting edge or carina. This taxonomically problematic genus is currently composed of seven species which show a wide variety of skull and tooth morphologies. Here we assess the craniodental disparity in Temnodontosaurus using a series of functionally informative traits. We describe the range of tooth morphologies in the genus in detail, including the first examples of serrated carinae in ichthyosaurians. These consist of false denticles created by the interaction of enamel ridgelets with the carinal keel, as well as possible cryptic true denticles only visible using scanning electron microscopy. We also find evidence for heterodonty in the species T. platyodon, with unicarinate mesial teeth likely playing a role in prey capture and labiolingually compressed, bicarinate distal teeth likely involved in prey processing. This type of heterodonty appears to be convergent with a series of other marine amniotes including early cetaceans. Overall, the species currently referred to as the genus Temnodontosaurus show a range of craniodental configurations allowing prey to be captured and processed in different ways – for example, T. eurycephalus has a deep snout and relatively small bicarinate teeth likely specialised for increased wound infliction and grip‐and‐tear feeding, whereas T. platyodon has a more elongate yet robust snout and larger teeth and may be more adapted for grip‐and‐shear feeding. These results suggest the existence of niche partitioning at higher trophic levels in Early Jurassic ichthyosaurians and have implications for future work on the taxonomy of this wastebasket genus, as well as for research into the ecology of other extinct megapredatory marine tetrapods.
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