Feeding in Aquatic Mammals: An Evolutionary and Functional Approach

Marshall, Christopher D.; Pyenson, Nicholas D.

doi:10.1007/978-3-030-13739-7_19

Cited by 19 publications

(20 citation statements)

References 168 publications

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“…Although pinnipeds do not masticate, consuming whole prey, otariids can chop large prey, breaking it into smaller pieces that are then consumed whole [51]. A stronger bite force would enable individuals to forage on larger prey [52]. The non-significant effect of the MA on the δ 15 N values suggests that bite force in sympatric otariids might have been achieved by alternative factors including shifts in muscle configuration.…”

Section: Discussionmentioning

confidence: 99%

Feeding morphology and body size shape resource partitioning in an eared seal community

et al. 2023

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Body size and feeding morphology influence how animals partition themselves within communities. We tested the relationships among sex, body size, skull morphology and foraging in sympatric otariids (eared seals) from the eastern North Pacific Ocean, the most diverse otariid community in the world. We recorded skull measurements and stable carbon ( δ 13 C) and nitrogen ( δ 15 N) isotope values (proxies for foraging) from museum specimens in four sympatric species: California sea lions ( Zalophus californianus ), Steller sea lions ( Eumetopias jubatus ), northern fur seals ( Callorhinus ursinus ) and Guadalupe fur seals ( Arctocephalus townsendi ). Species and sexes had statistical differences in size, skull morphology and foraging significantly affecting the δ 13 C values. Sea lions had higher δ 13 C values than fur seals, and males of all species had higher values than females. The δ 15 N values were correlated with species and feeding morphology; individuals with stronger bite forces had higher δ 15 N values. We also found a significant community-wide correlation between skull length (indicator of body length), and foraging, with larger individuals having nearshore habitat preferences, and consuming higher trophic level prey than smaller individuals. Still, there was no consistent association between these traits at the intraspecific level, indicating that other factors might account for foraging variability.

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Section: Discussionmentioning

confidence: 99%

Feeding morphology and body size shape resource partitioning in an eared seal community

et al. 2023

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“…7A). In modern cetaceans, a long and slender rostrum with several small conical and homodont teeth is often coupled with a raptorial snap feeder-like hunting strategy, associated with a mostly piscivore diet (e.g., Stenella longirostris , Pontoporia , Inia and Platanista; Marx, Lambert & Uhen, 2016 ; Marshall & Pyenson, 2019 ). A longirostrine skull enables high velocity at the jaw tips, at the expense of biting forces, which is advantageous for capturing small elusive prey if combined to a rapid snapping of the jaws and fast lateral or vertical movements of the rostrum.…”

Section: Discussionmentioning

confidence: 99%

Cranial anatomy ofBesanosaurus leptorhynchusDal Sasso & Pinna, 1996 (Reptilia: Ichthyosauria) from the Middle Triassic Besano Formation of Monte San Giorgio, Italy/Switzerland: taxonomic and palaeobiological implications

Bindellini

Wolniewicz

Miedema

et al. 2021

PeerJ

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Besanosaurus leptorhynchus Dal Sasso & Pinna, 1996 was described on the basis of a single fossil excavated near Besano (Italy) nearly three decades ago. Here, we re-examine its cranial osteology and assign five additional specimens to B. leptorhynchus, four of which were so far undescribed. All of the referred specimens were collected from the Middle Triassic outcrops of the Monte San Giorgio area (Italy/Switzerland) and are housed in various museum collections in Europe. The revised diagnosis of the taxon includes the following combination of cranial characters: extreme longirostry; an elongate frontal not participating in the supratemporal fenestra; a prominent ‘triangular process’ of the quadrate; a caudoventral exposure of the postorbital on the skull roof; a prominent coronoid (preglenoid) process of the surangular; tiny conical teeth with coarsely-striated crown surfaces and deeply-grooved roots; mesial maxillary teeth set in sockets; distal maxillary teeth set in a short groove. All these characters are shared with the holotype of Mikadocephalus gracilirostris Maisch & Matzke, 1997, which we consider as a junior synonym of B. leptorhynchus. An updated phylogenetic analysis, which includes revised scores for B. leptorhynchus and several other shastasaurids, recovers B. leptorhynchus as a basal merriamosaurian, but it is unclear if Shastasauridae form a clade, or represent a paraphyletic group. The inferred body length of the examined specimens ranges from 1 m to about 8 m. The extreme longirostry suggests that B. leptorhynchus primarily fed on small and elusive prey, feeding lower in the food web than an apex predator: a novel ecological specialisation never reported before the Anisian in a large diapsid. This specialization might have triggered an increase of body size and helped to maintain low competition among the diverse ichthyosaur fauna of the Besano Formation.

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“…Like terrestrial vertebrates, aquatic vertebrates can simply grasp items with teeth and jaws. This basic grasping feeding method is commonly classified as raptorial ("seizing") feeding, or simply as biting (Marshall and Goldbogen, 2015;Marshall and Pyenson, 2019). Because the predator's body or its jaws normally simply overcome prey by moving faster, this typically involves ram ingestion (Werth, 2000).…”

Section: Prey Acquisitionmentioning

confidence: 99%

Osteological correlates of evolutionary transitions in cetacean feeding and related oropharyngeal functions

Werth

Beatty

2023

Front. Ecol. Evol.

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Teeth are often the first structures that anatomists and paleontologists examine to understand the ecology and morphology of feeding, both because teeth are highly specialized structures that provide precise information, and because they are among the best and most commonly preserved fossils. Unfortunately, many fragmentary fossil and recent specimens lack teeth, and some come from edentulous individuals and taxa, as in mysticete (baleen) whales. In our broad comparative review, we survey non-dental osteological features that, due to size, shape, arrangement, and surface features reflecting muscle attachments, provide useful clues to general or specific aspects of prey capture, intraoral transport, processing, or swallowing. We focus on hyoid, palatal, and pterygoid bones, mandibular symphyses and processes such as the coronoid, and the temporal fossa and zygomatic arch, as well as adjacent cranial bones relating to oral and pharyngeal anatomy. These bones relate to muscles of five general locations especially indicative of feeding: mandibular, hyoid, tongue, pharyngeal, and facial regions. Together these bones and muscles affect feeding and related activities including suckling and breathing. We discuss osteological correlates that provide special relevance to key transitions in cetacean evolutionary history, such as the shift from predominantly terrestrial to aquatic feeding, the shift from typical mammalian mastication to swallowing prey entirely or nearly whole, and the separation of respiratory and digestive passages. We also point to examples of modern specialists in these anatomical optima for different modes of prey capture, intraoral transport, processing, and swallowing. Although we focus on cetaceans, our approach is broadly relevant to all vertebrates, notably other marine tetrapods.

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Feeding in Aquatic Mammals: An Evolutionary and Functional Approach

Cited by 19 publications

References 168 publications

Feeding morphology and body size shape resource partitioning in an eared seal community

Feeding morphology and body size shape resource partitioning in an eared seal community

Cranial anatomy ofBesanosaurus leptorhynchusDal Sasso & Pinna, 1996 (Reptilia: Ichthyosauria) from the Middle Triassic Besano Formation of Monte San Giorgio, Italy/Switzerland: taxonomic and palaeobiological implications

Osteological correlates of evolutionary transitions in cetacean feeding and related oropharyngeal functions

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