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Marramà G, Villalobos‐Segura E, Zorzin R, Kriwet J, Carnevale G. The evolutionary origin of the durophagous pelagic stingray ecomorph. Palaeontology 2023; 66:pala.12669. [PMID: 37533696 PMCID: PMC7614867 DOI: 10.1111/pala.12669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Accepted: 05/23/2023] [Indexed: 08/04/2023]
Abstract
Studies of the origin of evolutionary novelties (novel traits, feeding modes, behaviours, ecological niches, etc.) have considered a number of taxa experimenting with new body plans, allowing them to occupy new habitats and exploit new trophic resources. In the marine realm, colonization of pelagic environments by marine fishes occurred recurrently through time. Stingrays (Myliobatiformes) are a diverse clade of batoid fishes commonly known to possess venomous tail stings. Current hypotheses suggest that stingrays experimented with a transition from a benthic to a pelagic/benthopelagic habitat coupled with a transition from a non-durophagous diet to extreme durophagy. However, there is no study detailing macroevolutionary patterns to understand how and when habitat shift and feeding specialization arose along their evolutionary history. A new exquisitely preserved fossil stingray from the Eocene Konservat-Lagerstätte of Bolca (Italy) exhibits a unique mosaic of plesiomorphic features of the rajobenthic ecomorph, and derived traits of aquilopelagic taxa, that helps to clarify the evolutionary origin of durophagy and pelagic lifestyle in stingrays. A scenario of early evolution of the aquilopelagic ecomorph is proposed based on new data, and the possible adaptive meaning of the observed evolutionary changes is discussed. The body plan of †Dasyomyliobatis thomyorkei gen. et sp. nov. is intermediate between the rajobenthic and more derived aquilopelagic stingrays, supporting its stem phylogenetic position and the hypothesis that the aquilopelagic body plan arose in association with the evolution of durophagy and pelagic lifestyle from a benthic, soft-prey feeder ancestor.
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Affiliation(s)
- Giuseppe Marramà
- Dipartimento di Scienze della TerraUniversità degli Studi di TorinoVia Valperga Caluso 3510125TurinItaly
| | | | - Roberto Zorzin
- Museo Civico di Storia Naturale di VeronaLungadige Porta Vittoria 937129VeronaItaly
| | - Jürgen Kriwet
- Department of PalaeontologyUniversity of ViennaJosef‐Holaubek‐Platz 21090ViennaAustria
| | - Giorgio Carnevale
- Dipartimento di Scienze della TerraUniversità degli Studi di TorinoVia Valperga Caluso 3510125TurinItaly
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2
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Neaux D, Louail M, Ferchaud S, Surault J, Merceron G. Experimental assessment of the relationship between diet and mandibular morphology using a pig model: new insights for paleodietary reconstructions. Anat Rec (Hoboken) 2022; 305:3150-3160. [PMID: 35142076 DOI: 10.1002/ar.24895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 01/20/2022] [Accepted: 01/29/2022] [Indexed: 11/10/2022]
Abstract
Dietary habits exert significant selective pressures on anatomical structures in animals, leading to substantial morphological adaptations. Yet, the relationships between the mandible and diet are still unclear, raising issues for paleodietary reconstructions notably. To assess the impact of food hardness and size on morphological structures, we used an experimental baseline using a model based on the domestic pig, an omnivorous mammal with bunodont, thick-enameled dentition, and chewing movements similar to hominids. We hypothesized that the consumption of different types of seeds would result in substantial differences in the morphology of the mandible despite similar overall diets. The experiment was conducted on four groups of juvenile pigs fed with mixed cereal and soy flours. The control group received only flours. We supplemented the four others with either 10 hazelnuts, 30 hazelnuts, 30% barley seeds or 20% corn kernels per day. We investigated the shape differences between the controlled-fed groups using three-dimensional geometric morphometrics. Our results provide strong evidence that the supplemental consumption of a significant amount of seeds for a short period (95 days) substantially modify the mandibular morphology of pigs. Our analyses suggest that this shape differentiation is due to the size of the seeds, requiring high and repeated bite force, rather than their hardness. These results provide new perspectives for the use of mandibular morphology as a proxy in paleodietary reconstructions complementing dental microwear textures analyses. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Dimitri Neaux
- Archéozoologie, Archéobotanique: Sociétés, Pratiques et Environnements, UMR 7209, Muséum national d'Histoire naturelle CNRS, Paris, France.,Laboratoire PALEVOPRIM, UMR 7262 CNRS, Université de Poitiers, Poitiers, France
| | - Margot Louail
- Laboratoire PALEVOPRIM, UMR 7262 CNRS, Université de Poitiers, Poitiers, France
| | | | - Jérôme Surault
- Laboratoire PALEVOPRIM, UMR 7262 CNRS, Université de Poitiers, Poitiers, France
| | - Gildas Merceron
- Laboratoire PALEVOPRIM, UMR 7262 CNRS, Université de Poitiers, Poitiers, France
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3
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Bicknell RDC, Holmes JD, Edgecombe GD, Losso SR, Ortega-Hernández J, Wroe S, Paterson JR. Biomechanical analyses of Cambrian euarthropod limbs reveal their effectiveness in mastication and durophagy. Proc Biol Sci 2021; 288:20202075. [PMID: 33499790 DOI: 10.1098/rspb.2020.2075] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Durophagy arose in the Cambrian and greatly influenced the diversification of biomineralized defensive structures throughout the Phanerozoic. Spinose gnathobases on protopodites of Cambrian euarthropod limbs are considered key innovations for shell-crushing, yet few studies have demonstrated their effectiveness with biomechanical models. Here we present finite-element analysis models of two Cambrian trilobites with prominent gnathobases-Redlichia rex and Olenoides serratus-and compare these to the protopodites of the Cambrian euarthropod Sidneyia inexpectans and the modern American horseshoe crab, Limulus polyphemus. Results show that L. polyphemus, S. inexpectans and R. rex have broadly similar microstrain patterns, reflecting effective durophagous abilities. Conversely, low microstrain values across the O. serratus protopodite suggest that the elongate gnathobasic spines transferred minimal strain, implying that this species was less well-adapted to masticate hard prey. These results confirm that Cambrian euarthropods with transversely elongate protopodites bearing short, robust gnathobasic spines were likely durophages. Comparatively, taxa with shorter protopodites armed with long spines, such as O. serratus, were more likely restricted to a soft food diet. The prevalence of Cambrian gnathobase-bearing euarthropods and their various feeding specializations may have accelerated the development of complex trophic relationships within early animal ecosystems, especially the 'arms race' between predators and biomineralized prey.
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Affiliation(s)
- Russell D C Bicknell
- Palaeoscience Research Centre, School of Environmental & Rural Science University of New England, Armidale, NSW 2351, Australia.,Function, Evolution and Anatomy Research Lab, School of Environmental and Rural Science, University of New England, Armidale, NSW 2351, Australia
| | - James D Holmes
- School of Biological Sciences, University of Adelaide, North Terrace, Adelaide, SA 5005, Australia
| | - Gregory D Edgecombe
- Department of Earth Sciences, The Natural History Museum, London SW7 5BD, UK
| | - Sarah R Losso
- Museum of Comparative Zoology and Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, MA 02138, USA
| | - Javier Ortega-Hernández
- Museum of Comparative Zoology and Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, MA 02138, USA
| | - Stephen Wroe
- Palaeoscience Research Centre, School of Environmental & Rural Science University of New England, Armidale, NSW 2351, Australia.,Function, Evolution and Anatomy Research Lab, School of Environmental and Rural Science, University of New England, Armidale, NSW 2351, Australia
| | - John R Paterson
- Palaeoscience Research Centre, School of Environmental & Rural Science University of New England, Armidale, NSW 2351, Australia
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4
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St. John ME, Dixon K, Martin CH. Oral shelling within an adaptive radiation of pupfishes: Testing the adaptive function of a novel nasal protrusion and behavioural preference. J Fish Biol 2020; 97:163-171. [PMID: 32278332 PMCID: PMC8183458 DOI: 10.1111/jfb.14344] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 04/05/2020] [Accepted: 04/08/2020] [Indexed: 06/11/2023]
Abstract
Dietary specialization on hard prey items, such as mollusks and crustaceans, is commonly observed in a diverse array of fish species. Many fish consume these types of prey by crushing the shell to consume the soft tissue within, but a few fishes extricate the soft tissue without breaking the shell using a method known as oral shelling. Oral shelling involves pulling a mollusc from its shell and it may be a way to subvert an otherwise insurmountable shell defence. However, the biomechanical requirements and potential adaptations for oral shelling are unknown. Here, we test the hypothesis that a novel nasal protrusion is an adaptation for oral shelling in the durophagous pupfish (Cyprinodon brontotheroides). We first demonstrate oral shelling in this species and then predict that a larger nasal protrusion would allow pupfish to consume larger snails. Durophagous pupfish are found within an endemic radiation of pupfish on San Salvador Island, Bahamas. We took advantage of closely related sympatric species and outgroups to test: (a) whether durophagous pupfish shell and consume more snails than other species, (b) if F1 and F2 durophagous hybrids consume similar amounts of snails as purebred durophagous pupfish, and (c) if nasal protrusion size in parental and hybrid populations increases the maximum size of consumed snails. We found that durophagous pupfish and their hybrids consumed the most snails, but did not find a strong association between nasal protrusion size and maximum snail size consumed within the parental or F2 hybrid population, suggesting that the size of their novel nasal protrusion does not provide a major benefit in oral shelling. Instead, we suggest that the nasal protrusion may increase feeding efficiency, act as a sensory organ, or is a sexually selected trait, and that a strong feeding preference may be most important for oral shelling.
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Affiliation(s)
- Michelle E. St. John
- Department of Integrative Biology and Museum of Vertebrate Zoology, University of California, Berkeley, CA 94720, USA
| | - Kristi Dixon
- Department of Biology, University of North Carolina at Chapel Hill, 120 South Rd., NC 27599, USA
| | - Christopher H. Martin
- Department of Integrative Biology and Museum of Vertebrate Zoology, University of California, Berkeley, CA 94720, USA
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5
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Rutledge KM, Summers AP, Kolmann MA. Killing them softly: Ontogeny of jaw mechanics and stiffness in mollusk-feeding freshwater stingrays. J Morphol 2019; 280:796-808. [PMID: 30950541 DOI: 10.1002/jmor.20984] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 03/15/2019] [Accepted: 03/16/2019] [Indexed: 12/17/2022]
Abstract
Durophagous predators consume hard-shelled prey such as bivalves, gastropods, and large crustaceans, typically by crushing the mineralized exoskeleton. This is costly from the point of view of the bite forces involved, handling times, and the stresses inflicted on the predator's skeleton. It is not uncommon for durophagous taxa to display an ontogenetic shift from softer to harder prey items, implying that it is relatively difficult for smaller animals to consume shelled prey. Batoid fishes (rays, skates, sawfishes, and guitarfishes) have independently evolved durophagy multiple times, despite the challenges associated with crushing prey harder than their own cartilaginous skeleton. Potamotrygon leopoldi is a durophagous freshwater ray endemic to the Xingu River in Brazil, with a jaw morphology superficially similar to its distant durophagous marine relatives, eagle rays (e.g., Aetomylaeus, Aetobatus). We used second moment of area as a proxy for the ability to resist bending and analyzed the arrangement of the mineralized skeleton of the jaw of P. leopoldi over ontogeny using data from computed tomography (CT) scans. The jaws of P. leopoldi do not resist bending nearly as well as other durophagous elasmobranchs, and the jaws are stiffest nearest the joints rather than beneath the dentition. While second moment has similar material distribution over ontogeny, mineralization of the jaws under the teeth increases with age. Neonate rays have low jaw stiffness and poor mineralization, suggesting that P. leopoldi may not feed on hard-shelled prey early in life. These differences in the shape, stiffness and mineralization of the jaws of P. leopoldi compared to its durophagous relatives show there are several solutions to the problem of crushing shelled prey with a compliant skeleton.
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Affiliation(s)
- Kelsi M Rutledge
- Department of Biology, Friday Harbor Laboratories, University of Washington, Friday Harbor, Washington.,Department of Ecology and Evolutionary Biology, University of California, Los Angeles, California
| | - Adam P Summers
- Department of Biology, Friday Harbor Laboratories, University of Washington, Friday Harbor, Washington
| | - Matthew A Kolmann
- Department of Biology, Friday Harbor Laboratories, University of Washington, Friday Harbor, Washington.,Department of Biological Sciences, George Washington University, Washington, D.C.,Department of Ichthyology, Royal Ontario Museum, Toronto, Ontario
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6
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Bicknell RDC, Ledogar JA, Wroe S, Gutzler BC, Watson WH, Paterson JR. Computational biomechanical analyses demonstrate similar shell-crushing abilities in modern and ancient arthropods. Proc Biol Sci 2018; 285:rspb.2018.1935. [PMID: 30355715 DOI: 10.1098/rspb.2018.1935] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 10/05/2018] [Indexed: 12/28/2022] Open
Abstract
The biology of the American horseshoe crab, Limulus polyphemus, is well documented-including its dietary habits, particularly the ability to crush shell with gnathobasic walking appendages-but virtually nothing is known about the feeding biomechanics of this iconic arthropod. Limulus polyphemus is also considered the archetypal functional analogue of various extinct groups with serial gnathobasic appendages, including eurypterids, trilobites and other early arthropods, especially Sidneyia inexpectans from the mid-Cambrian (508 Myr) Burgess Shale of Canada. Exceptionally preserved specimens of S. inexpectans show evidence suggestive of durophagous (shell-crushing) tendencies-including thick gnathobasic spine cuticle and shelly gut contents-but the masticatory capabilities of this fossil species have yet to be compared with modern durophagous arthropods. Here, we use advanced computational techniques, specifically a unique application of 3D finite-element analysis (FEA), to model the feeding mechanics of L. polyphemus and S. inexpectans: the first such analyses of a modern horseshoe crab and a fossil arthropod. Results show that mechanical performance of the feeding appendages in both arthropods is remarkably similar, suggesting that S. inexpectans had similar shell-crushing capabilities to L. polyphemus This biomechanical solution to processing shelly food therefore has a history extending over 500 Myr, arising soon after the first shell-bearing animals. Arrival of durophagous predators during the early phase of animal evolution undoubtedly fuelled the Cambrian 'arms race' that involved a rapid increase in diversity, disparity and abundance of biomineralized prey species.
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Affiliation(s)
- Russell D C Bicknell
- Palaeoscience Research Centre, School of Environmental and Rural Science, University of New England, Armidale, New South Wales 2351, Australia .,Function, Evolution and Anatomy Research Lab, School of Environmental and Rural Science, University of New England, Armidale, New South Wales 2351, Australia
| | - Justin A Ledogar
- Palaeoscience Research Centre, School of Environmental and Rural Science, University of New England, Armidale, New South Wales 2351, Australia.,Function, Evolution and Anatomy Research Lab, School of Environmental and Rural Science, University of New England, Armidale, New South Wales 2351, Australia.,Department of Evolutionary Biology, Duke University, Durham, NC 27708, USA
| | - Stephen Wroe
- Palaeoscience Research Centre, School of Environmental and Rural Science, University of New England, Armidale, New South Wales 2351, Australia.,Function, Evolution and Anatomy Research Lab, School of Environmental and Rural Science, University of New England, Armidale, New South Wales 2351, Australia
| | - Benjamin C Gutzler
- Department of Biological Sciences and School of Marine Science and Ocean Engineering, University of New Hampshire, Durham, NH 03824, USA
| | - Winsor H Watson
- Department of Biological Sciences and School of Marine Science and Ocean Engineering, University of New Hampshire, Durham, NH 03824, USA
| | - John R Paterson
- Palaeoscience Research Centre, School of Environmental and Rural Science, University of New England, Armidale, New South Wales 2351, Australia
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7
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Dietl GP, Nagel-Myers J, Aronson RB. Indirect effects of climate change altered the cannibalistic behaviour of shell-drilling gastropods in Antarctica during the Eocene. R Soc Open Sci 2018; 5:181446. [PMID: 30473865 PMCID: PMC6227939 DOI: 10.1098/rsos.181446] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 10/05/2018] [Indexed: 06/09/2023]
Abstract
The fossil record from Seymour Island, Antarctic Peninsula, provides a record of biotic response to the onset of global climatic cooling during the Eocene. Using drilling traces-small, round holes preserved on prey shells-we examined the effect of a cooling pulse 41 Ma on the cannibalistic behaviour of predatory naticid gastropods. We predicted that cannibalistic attacks would decline in response to the cooling climate, reflecting reduced activity levels, energy requirements and constraints on the chemically aided drilling process of the naticids. Surprisingly, however, cannibalism frequencies did not change. This counterintuitive result is best explained by a sharp reduction in durophagous (shell-crushing) predation in shallow-benthic communities in Antarctica that also occurred as the climate cooled. Reduced durophagous predation may have created a less-risky environment for foraging naticids, stimulating cannibalistic behaviour. The change in the top-down control exerted by shell-crushing predators on naticids may have counteracted the direct, negative effects of declining temperatures on the predatory performance of naticids. Our results suggest that the long-term consequences of climate change cannot be predicted solely from its direct effects on predation, because the temperature can have large indirect effects on consumer-resource interactions, especially where risk-effects dominate.
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Affiliation(s)
- Gregory P. Dietl
- Paleontological Research Institution, Ithaca, NY 14850, USA
- Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, NY 14853, USA
| | | | - Richard B. Aronson
- Department of Ocean Engineering and Marine Sciences, Florida Institute of Technology, Melbourne, FL 32901, USA
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8
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Latimer AE, Giles S. A giant dapediid from the Late Triassic of Switzerland and insights into neopterygian phylogeny. R Soc Open Sci 2018; 5:180497. [PMID: 30225040 PMCID: PMC6124034 DOI: 10.1098/rsos.180497] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Accepted: 07/09/2018] [Indexed: 06/08/2023]
Abstract
A new Triassic neopterygian is described on the basis of a large three-dimensional neurocranium from the Rhaetian (Late Triassic) of the Kössen Formation (Schesaplana, Grisons, Switzerland). CT scanning reveals neurocranial features similar to Dapedium, suggesting that this new genus, Scopulipiscis saxciput gen. et sp. nov., was deep-bodied and potentially durophagous, although no associated dental material is known. An expanded phylogenetic analysis of actinopterygians resolves Dapediidae as a clade (inclusive of Tetragonolepis), although fails to recover any characters supporting the monophyly of the genus Dapedium. Dapediids are resolved as stem holosteans, filling a conspicuous gap in early neopterygian relationships. Pycnodonts, previously suggested as either stem teleosts or the sister group to dapediids, are resolved as a clade on the neopterygian stem. Similarities between the new taxon described here and Dapedium provide insights into morphological disparity within early members of the group-suggesting that the ecological expansion of dapediids originated prior to the End-Triassic extinction-as well as contributing to a growing understanding of endocranial anatomy in Palaeozoic and Early Mesozoic actinopterygians.
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Affiliation(s)
- Ashley E. Latimer
- Paleontological Institute and Museum, University of Zurich, Zurich 8052, Switzerland
| | - Sam Giles
- Department of Earth Sciences, University of Oxford, Oxford OX1 3AN, UK
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9
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Finucci B, Gallus L, Amaroli A, Candiani S, Rottigni M, Masini MA, Ferrando S. Vacchi's palatal organ: a widespread trait in Holocephali. J Fish Biol 2018; 92:1177-1182. [PMID: 29465164 DOI: 10.1111/jfb.13553] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 01/02/2018] [Indexed: 06/08/2023]
Abstract
A palatal organ, possibly used for food sorting and processing, has previously been identified among the vomerine toothplates of the chimaeroid Chimaera monstrosa. In this study, the palatal organ was described in six additional species, confirming it is a widespread trait among holocephalans. It is proposed that this palatal structure, which appears to differ in shape according to each chimaeroid's degree of durophagy and is not homologous to the palatal structure described in teleosts, be hereby referred to as Vacchi's organ.
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Affiliation(s)
- B Finucci
- School of Biological Sciences, Victoria University of Wellington, PO Box 600, Wellington, 6140, New Zealand
| | - L Gallus
- Department of Earth, Environmental, and Life Science (DISTAV), University of Genoa, Corso Europa 26, I-16132, Genoa, Italy
| | - A Amaroli
- Department of Earth, Environmental, and Life Science (DISTAV), University of Genoa, Corso Europa 26, I-16132, Genoa, Italy
- Department of Surgery (DISC), University of Genoa, Largo Rosanna Benzi 8, I-16132, Genoa, Italy
| | - S Candiani
- Department of Earth, Environmental, and Life Science (DISTAV), University of Genoa, Corso Europa 26, I-16132, Genoa, Italy
| | - M Rottigni
- Department of Earth, Environmental, and Life Science (DISTAV), University of Genoa, Corso Europa 26, I-16132, Genoa, Italy
| | - M A Masini
- Department of Sciences and Technological Innovation (DISIT), University of Eastern Piedmont, Viale Teresa Michel 11, I-15121, Alessandria, Italy
| | - S Ferrando
- Department of Earth, Environmental, and Life Science (DISTAV), University of Genoa, Corso Europa 26, I-16132, Genoa, Italy
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10
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Hernandez LP, Adriaens D, Martin CH, Wainwright PC, Masschaele B, Dierick M. Building trophic specializations that result in substantial niche partitioning within a young adaptive radiation. J Anat 2017; 232:173-185. [PMID: 29161774 DOI: 10.1111/joa.12742] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/27/2017] [Indexed: 02/06/2023] Open
Abstract
Dietary partitioning often accompanies the increased morphological diversity seen during adaptive radiations within aquatic systems. While such niche partitioning would be expected in older radiations, it is unclear how significant morphological divergence occurs within a shorter time period. Here we show how differential growth in key elements of the feeding mechanism can bring about pronounced functional differences among closely related species. An incredibly young adaptive radiation of three Cyprinodon species residing within hypersaline lakes in San Salvador Island, Bahamas, has recently been described. Characterized by distinct head shapes, gut content analyses revealed three discrete feeding modes in these species: basal detritivory as well as derived durophagy and lepidophagy (scale-feeding). We dissected, cleared and stained, and micro-CT scanned species to assess functionally relevant differences in craniofacial musculoskeletal elements. The widespread feeding mode previously described for cyprinodontiforms, in which the force of the bite may be secondary to the requisite dexterity needed to pick at food items, is modified within both the scale specialist and the durophagous species. While the scale specialist has greatly emphasized maxillary retraction, using it to overcome the poor mechanical advantage associated with scale-eating, the durophage has instead stabilized the maxilla. In all species the bulk of the adductor musculature is composed of AM A1. However, the combined masses of both adductor mandibulae (AM) A1 and A3 in the scale specialist were five times that of the other species, showing the importance of growth in functional divergence. The scale specialist combines plesiomorphic jaw mechanisms with both a hypertrophied AM A1 and a slightly modified maxillary anatomy (with substantial functional implications) to generate a bite that is both strong and allows a wide range of motion in the upper jaw, two attributes that normally tradeoff mechanically. Thus, a significant feeding innovation (scale-eating, rarely seen in fishes) may evolve based largely on allometric changes in ancestral structures. Alternatively, the durophage shows reduced growth with foreshortened jaws that are stabilized by an immobile maxilla. Overall, scale specialists showed the most divergent morphology, suggesting that selection for scale-biting might be stronger or act on a greater number of traits than selection for either detritivory or durophagy. The scale specialist has colonized an adaptive peak that few lineages have climbed. Thus, heterochronic changes in growth can quickly produce functionally relevant change among closely related species.
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Affiliation(s)
- Luz Patricia Hernandez
- Department of Biological Sciences, The George Washington University, Washington, DC, USA
| | - Dominique Adriaens
- Evolutionary Morphology of Vertebrates, Ghent University, Ghent, Belgium
| | - Christopher H Martin
- Department of Biology, University of North Carolina, Chapel Hill, Chapel Hill, NC, USA
| | - Peter C Wainwright
- Department of Evolution & Ecology, University of California, Davis, Davis, CA, USA
| | - Bert Masschaele
- Department of Subatomic and Radiation Physics, Ghent University, Ghent, Belgium
| | - Manuel Dierick
- Department of Subatomic and Radiation Physics, Ghent University, Ghent, Belgium
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11
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Varella HR, Zuanon J, Kullander SO, López-Fernández H. Teleocichla preta, a new species of cichlid from the Rio Xingu Basin in Brazil (Teleostei: Cichlidae). J Fish Biol 2016; 89:1551-1569. [PMID: 27349202 DOI: 10.1111/jfb.13053] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Accepted: 04/28/2016] [Indexed: 06/06/2023]
Abstract
Teleocichla preta nov. sp. inhabits the rapids along the Rio Xingu and lower portion of the Rio Iriri. It is the largest species in the genus, reaching 121·3 mm standard length (LS ) while others do not reach more than 87·8 mm LS . Teleocichla preta is distinguished from all other species of Teleocichla by the unique blackish (in live specimens) or dark brown (preserved specimens) overall colouration of the body, which masks the faint vertical bars or zig-zag pattern of blotches on the flanks. Teleocichla preta also has a deeper body and a deep laterally compressed caudal peduncle, unlike any other congener, as well as a stout lower pharyngeal tooth plate bearing molariform teeth on its median area.
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Affiliation(s)
- H R Varella
- Museu de Zoologia da Universidade de São Paulo, Caixa Postal 42494, 04218-970, São Paulo, SP, Brazil
| | - J Zuanon
- Coordenação de Biodiversidade, Caixa Postal 2223, Instituto Nacional de Pesquisas da Amazônia, 69080-971, Manaus, AM, Brazil
| | - S O Kullander
- Department of Zoology, Swedish Museum of Natural History, P. O. Box 50007, SE-104 05, Stockholm, Sweden
| | - H López-Fernández
- Department of Natural History, Royal Ontario Museum, 100 Queen's Park, Toronto, ON, M5S 2C6, Canada
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, ON, M5S 3B2, Canada
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Bochaton C, Boistel R, Charles L. X-ray microtomography provides first data about the feeding behaviour of an endangered lizard, the Montserrat galliwasp (Diploglossus montisserrati). R Soc Open Sci 2015; 2:150461. [PMID: 27019732 PMCID: PMC4807453 DOI: 10.1098/rsos.150461] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 11/20/2015] [Indexed: 06/05/2023]
Abstract
Reporting the diet of recently extinct or very rare taxa, only known by a few museum specimens, is challenging. This study uses X-ray microtomography, a non-destructive investigation method, to obtain the first data about feeding behaviours in the Montserrat galliwasp (Diploglossus montisserrati) by scanning one of the two specimens known to date. The scans revealed the occurrence of shell fragments of a freshwater snail (Omalonyx matheroni) in the digestive tract of the specimen. This data combined with morphological evidence shows the occurrence of a durophagous feeding habit and a possible tendency of association with freshwater environments. This information could be crucial to save this critically endangered lizard endemic on Montserrat island.
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Affiliation(s)
- C. Bochaton
- Laboratoire Archéozoologie et Archéobotanique: Sociétés, Pratiques et Environnements, UMR 7209 – CNRS, MNHN, Muséum national d'Histoire naturelle, Sorbonne Universités, 55 rue Buffon, CP 56, Paris 75005, France
- Institut de Systématique, Évolution, Biodiversité, ISYEB – UMR 7205 – CNRS, MNHN, UPMC, EPHE, Muséum national d'Histoire naturelle, Sorbonne Universités, 57 rue Cuvier, CP 30, Paris 75005, France
| | - R. Boistel
- Institut de Paléoprimatologie, Paléontologie Humaine: Evolution et Paléoenvironnements, UMR 7262–CNRS, Université de Poitiers, UFR SFA, Bât. B35, 6 rue Michel Brunet, TSA 51106, Poitiers 86073, France
| | - L. Charles
- Muséum d'Histoire naturelle de Bordeaux, 5 Place Bardineau, Bordeaux 33000, France
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Salas-Gismondi R, Flynn JJ, Baby P, Tejada-Lara JV, Wesselingh FP, Antoine PO. A Miocene hyperdiverse crocodylian community reveals peculiar trophic dynamics in proto-Amazonian mega-wetlands. Proc Biol Sci 2015; 282:20142490. [PMID: 25716785 DOI: 10.1098/rspb.2014.2490] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Amazonia contains one of the world's richest biotas, but origins of this diversity remain obscure. Onset of the Amazon River drainage at approximately 10.5 Ma represented a major shift in Neotropical ecosystems, and proto-Amazonian biotas just prior to this pivotal episode are integral to understanding origins of Amazonian biodiversity, yet vertebrate fossil evidence is extraordinarily rare. Two new species-rich bonebeds from late Middle Miocene proto-Amazonian deposits of northeastern Peru document the same hyperdiverse assemblage of seven co-occurring crocodylian species. Besides the large-bodied Purussaurus and Mourasuchus, all other crocodylians are new taxa, including a stem caiman-Gnatusuchus pebasensis-bearing a massive shovel-shaped mandible, procumbent anterior and globular posterior teeth, and a mammal-like diastema. This unusual species is an extreme exemplar of a radiation of small caimans with crushing dentitions recording peculiar feeding strategies correlated with a peak in proto-Amazonian molluscan diversity and abundance. These faunas evolved within dysoxic marshes and swamps of the long-lived Pebas Mega-Wetland System and declined with inception of the transcontinental Amazon drainage, favouring diversification of longirostrine crocodylians and more modern generalist-feeding caimans. The rise and demise of distinctive, highly productive aquatic ecosystems substantially influenced evolution of Amazonian biodiversity hotspots of crocodylians and other organisms throughout the Neogene.
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Affiliation(s)
- Rodolfo Salas-Gismondi
- Institut des Sciences de l'Évolution, Université de Montpellier, CNRS, IRD EPHE, Montpellier 34095, France Departamento de Paleontología de Vertebrados, Museo de Historia Natural, Universidad Nacional Mayor de San Marcos, Avenida Arenales 1256, Lima 14, Peru
| | - John J Flynn
- Division of Paleontology, American Museum of Natural History, New York, NY 10024-5192, USA
| | - Patrice Baby
- Géosciences-Environnements Toulouse, Université de Toulouse, UPS (SVT-OMP), CNRS, IRD, 14 Avenue Édouard Belin, Toulouse 31400, France Convenio IRD-PeruPetro, Avenida Luis Aldana 320, San Borja, Lima, Peru
| | - Julia V Tejada-Lara
- Departamento de Paleontología de Vertebrados, Museo de Historia Natural, Universidad Nacional Mayor de San Marcos, Avenida Arenales 1256, Lima 14, Peru Florida Museum of Natural History and Department of Biology, University of Florida, PO BOX 117800, Gainesville, FL 32611, USA
| | - Frank P Wesselingh
- Naturalis Biodiversity Center, P.O. Box 9517, 2300 RA, Leiden, The Netherlands
| | - Pierre-Olivier Antoine
- Institut des Sciences de l'Évolution, Université de Montpellier, CNRS, IRD EPHE, Montpellier 34095, France
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Kolmann MA, Huber DR, Motta PJ, Grubbs RD. Feeding biomechanics of the cownose ray, Rhinoptera bonasus, over ontogeny. J Anat 2015; 227:341-51. [PMID: 26183820 DOI: 10.1111/joa.12342] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/27/2015] [Indexed: 11/29/2022] Open
Abstract
Growth affects the performance of structure, so the pattern of growth must influence the role of a structure and an organism. Because animal performance is linked to morphological specialization, ontogenetic change in size may influence an organism's biological role. High bite force generation is presumably selected for in durophagous taxa. Therefore, these animals provide an excellent study system for investigating biomechanical consequences of growth on performance. An ontogenetic series of 27 cownose rays (Rhinoptera bonasus) were dissected in order to develop a biomechanical model of the feeding mechanism, which was then compared with bite forces measured from live rays. Mechanical advantage of the feeding apparatus was generally conserved throughout ontogeny, while an increase in the mass and cross-sectional area of the jaw adductors resulted in allometric gains in bite force generation. Of primary importance to forceful biting in this taxon is the use of a fibrocartilaginous tendon associated with the insertion of the primary jaw adductor division. This tendon may serve to redirect muscle forces anteriorly, transmitting them within the plane of biting. Measured bite forces obtained through electrostimulation of the jaw adductors in live rays were higher than predicted, possibly due to differences in specific tension of actual batoid muscle and that used in the model. Mass-specific bite forces in these rays are the highest recorded for elasmobranchs. Cownose rays exemplify a species that, through allometric growth of bite performance and morphological novelties, have expanded their ecological performance over ontogeny.
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Affiliation(s)
- Matthew A Kolmann
- Department of Biological Science, Florida State University, Tallahassee, FL, USA
| | - Daniel R Huber
- Department of Biology, University of Tampa, Tampa, FL, USA
| | - Philip J Motta
- Department of Integrative Biology, University of South Florida, Tampa, FL, USA
| | - R Dean Grubbs
- Florida State University Coastal and Marine Laboratory, St Teresa, FL, USA
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Desantis LRG, Haupt RJ. Cougars' key to survival through the Late Pleistocene extinction: insights from dental microwear texture analysis. Biol Lett 2014; 10:20140203. [PMID: 24759373 DOI: 10.1098/rsbl.2014.0203] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Cougars (Puma concolor) are one of only two large cats in North America to have survived the Late Pleistocene extinction (LPE), yet the specific key(s) to their relative success remains unknown. Here, we compare the dental microwear textures of Pleistocene cougars with sympatric felids from the La Brea Tar Pits in southern California that went extinct at the LPE (Panthera atrox and Smilodon fatalis), to clarify potential dietary factors that led to the cougar's persistence through the LPE. We further assess whether the physical properties of food consumed have changed over time when compared with modern cougars in southern California. Using dental microwear texture analysis (DMTA), which quantifies surface features in three dimensions, we find that modern and Pleistocene cougars are not significantly different from modern African lions in any DMTA attributes, suggesting moderate durophagy (i.e. bone processing). Pleistocene cougars from La Brea have significantly greater complexity and textural fill volume than Panthera atrox (inferred to have primarily consumed flesh from fresh kills) and significantly greater variance in complexity values than S. fatalis. Ultimately, these results suggest that cougars already used or adopted a more generalized dietary strategy during the Pleistocene that may have been key to their subsequent success.
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Affiliation(s)
- Larisa R G Desantis
- Department of Earth and Environmental Sciences, Vanderbilt University, , Nashville, TN 37240, USA
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Neenan JM, Li C, Rieppel O, Bernardini F, Tuniz C, Muscio G, Scheyer TM. Unique method of tooth replacement in durophagous placodont marine reptiles, with new data on the dentition of Chinese taxa. J Anat 2014; 224:603-13. [PMID: 24517163 DOI: 10.1111/joa.12162] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/02/2014] [Indexed: 11/30/2022] Open
Abstract
The placodonts of the Triassic period (~252-201 mya) represent one of the earliest and most extreme specialisations to a durophagous diet of any known reptile group. Exceptionally enlarged crushing tooth plates on the maxilla, dentary and palatine cooperated to form functional crushing areas in the buccal cavity. However, the extreme size of these teeth, combined with the unusual way they occluded, constrained how replacement occurred. Using an extensive micro-computed tomographic dataset of 11 specimens that span all geographic regions and placodont morphotypes, tooth replacement patterns were investigated. In addition, the previously undescribed dental morphologies and formulae of Chinese taxa are described for the first time and incorporated into the analysis. Placodonts have a unique tooth replacement pattern and results follow a phylogenetic trend. The plesiomorphic Placodus species show many replacement teeth at various stages of growth, with little or no discernible pattern. On the other hand, the more derived cyamodontoids tend to have fewer replacement teeth growing at any one time, replacing teeth unilaterally and/or in functional units, thus maintaining at least one functional crushing area at all times. The highly derived placochelyids have fewer teeth and, as a result, only have one or two replacement teeth in the upper jaw. This supports previous suggestions that these taxa had an alternative diet to other placodonts. Importantly, all specimens show at least one replacement tooth growing at the most posterior palatine tooth plates, indicating increased wear at this point and thus the most efficient functional crushing area.
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Affiliation(s)
- James M Neenan
- Palaeontological Institute and Museum, University of Zurich, Zurich, Switzerland
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Abstract
Organisms that are durophagous, hard prey consumers, have a diversity of tooth forms. To determine why we see this variation, we tested whether some tooth forms break shells better than others. We measured the force needed with three series of aluminium tooth models, which varied in concavity and the morphology of a stress concentrating cusp, to break a shell. We created functionally identical copies of two intertidal snail shells: the thicker shelled Nucella ostrina and the more ornamented Nucella lamellosa using a three-dimensional printer. In this way, we reduced variation in material properties between test shells, allowing us to test only the interaction of the experimental teeth with the two shell morphologies. We found that for all tooth shapes, thicker shells are harder to break than the thinner shells and that increased ornamentation has no discernible effect. Our results show that for both shell morphologies, domed and flat teeth break shells better than cupped teeth, and teeth with tall or skinny cusps break shells best. While our results indicate that there is an ideal tooth form for shell breaking, we do not see this shape in nature. This suggests a probable trade-off between tooth function and the structural integrity of the tooth.
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Affiliation(s)
- S B Crofts
- Department of Biology, University of Washington, , Seattle, WA 98195-1800, USA
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