Same but different: aquatic prey capture in paedomorphic and metamorphic Alpine newts

Heiss, Egon; Grell, Julia

doi:10.1186/s40851-019-0140-4

Cited by 8 publications

(17 citation statements)

References 66 publications

(95 reference statements)

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“…It was recently shown that metamorphosed salamandrid newts use loop-like movements of their hyobranchial apparatus (i.e., tongue) to translate food across the palatal dentition (i.e., tongue-palate rasping) [21]. It has also been suggested that salamandrids with a larval morphology cannot employ the same processing mechanism as metamorphic animals because of morphological constraints, including the lack of a exible tongue with su cient internal movement-potential and diverging dentition patterns in larval morphotypes [15,16]. To address the question of how processing differs between larval and metamorphosed salamandrid morphotypes of the same species, we examined heterochronic morphotypes of adult Alpine newts.…”

Section: Discussionmentioning

confidence: 99%

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Ontogenetic plasticity in cranial morphology is associated with a change in the food processing behavior in Alpine newts

Schwarz

Konow

Porro

et al. 2020

Preprint

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Background: The feeding apparatus of salamanders consists mainly of the cranium, mandible, teeth, hyobranchial apparatus and the muscles of the cranial region. The morphology of the feeding apparatus in turn determines the boundary conditions for possible food processing mechanisms. However, the morphology of the feeding apparatus changes substantially during metamorphosis, prompting the hypothesis that larvae might use a different food processing mechanism than post-metamorphic adults. Salamandrid newts with facultative metamorphosis are suitable for testing this hypothesis as adults with divergent feeding apparatus morphologies often coexist in the same population, share similar body sizes, and feed on overlapping prey spectra. Methods: We use high-speed videography to quantify the in vivo movements of key anatomical elements during food processing in paedomorphic and metamorphic Alpine newts (Ichthyosaura alpestris). Additionally, we use micro-computed tomography (μCT) to analyze morphological differences in the feeding apparatus of paedomorphic and metamorphic Alpine newts and sort them into late-larval, mid-metamorphic and post-metamorphic morphotypes. Results: Late-larval, mid-metamorphic and post-metamorphic individuals exhibited clear morphological differences in their feeding apparatus. Regardless of the paedomorphic state being externally evident, paedomorphic specimens can conceal different morphotypes (i.e., late-larval and mid-metamorphic morphotypes). Though feeding on the same prey under the same (aquatic) condition, food processing kinematics differed between late-larval, mid-metamorphic and post-metamorphic morphotypes. Conclusions: The food processing mechanism in the Alpine newt changes along with morphology of the feeding apparatus during ontogeny, from a mandible-based to a tongue-based processing mechanism as the mandible’s changing morphology prevents chewing and the tongue allows enhanced protraction. These results could indicate that early tetrapods, in analogy to salamanders, may have developed new feeding mechanisms in their aquatic environment and that these functional innovations may have later paved the way for terrestrial feeding mechanisms.

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Section: Discussionmentioning

confidence: 99%

“…The musculoskeletal components of the feeding apparatus of paedomorphic and post-metamorphic specimens were reconstructed from μCT scans [15]. timescales (x-axes) for comparison.…”

Section: Anatomical Analysis (µCt)mentioning

confidence: 99%

Ontogenetic plasticity in cranial morphology is associated with a change in the food processing behavior in Alpine newts

Schwarz

Konow

Porro

et al. 2020

Preprint

Self Cite

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“…Prior studies have hypothesized that, due to their different morphologies, heterochronic morphotypes differ in their feeding performance (capture success-rate) and feeding behavior [12][13][14]. Behavioral studies have shown that paedomorphs tend to have greater aquatic prey capture performance [12,14], but surprisingly, despite diverging prey capture performance and major differences in head morphology, there are only minor differences in prey capture kinematics between heterochronic morphotypes [13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

“…Second, processing might be affected more from differing feeding apparatus morphologies than capture and transport. This latter point becomes more evident if we consider changes in the structure, position and number of the teeth [26][27][28][29]; structural changes of the hyobranchial apparatus (i.e., developing from a gill-bearing to a tongue-bearing apparatus) [14,15,[30][31][32]; changes in the muscular and ligamentous suspension of the hyobranchial apparatus [33][34][35]; morphological changes of mandible and skull [15,[36][37][38]; as well as dramatic muscular reorganization [39,40] during metamorphosis in salamanders. All of the aforementioned characteristics impact intraoral food processing kinematics in salamanders [21,23].…”

Section: Introductionmentioning

confidence: 99%

Ontogenetic plasticity in cranial morphology is associated with a change in the food processing behavior in Alpine newts

et al. 2020

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Background The feeding apparatus of salamanders consists mainly of the cranium, mandible, teeth, hyobranchial apparatus and the muscles of the cranial region. The morphology of the feeding apparatus in turn determines the boundary conditions for possible food processing (i.e., intraoral mechanical reduction) mechanisms. However, the morphology of the feeding apparatus changes substantially during metamorphosis, prompting the hypothesis that larvae might use a different food processing mechanism than post-metamorphic adults. Salamandrid newts with facultative metamorphosis are suitable for testing this hypothesis as adults with divergent feeding apparatus morphologies often coexist in the same population, share similar body sizes, and feed on overlapping prey spectra. Methods We use high-speed videography to quantify the in vivo movements of key anatomical elements during food processing in paedomorphic and metamorphic Alpine newts (Ichthyosaura alpestris). Additionally, we use micro-computed tomography (μCT) to analyze morphological differences in the feeding apparatus of paedomorphic and metamorphic Alpine newts and sort them into late-larval, mid-metamorphic and post-metamorphic morphotypes. Results Late-larval, mid-metamorphic and post-metamorphic individuals exhibited clear morphological differences in their feeding apparatus. Regardless of the paedomorphic state being externally evident, paedomorphic specimens can conceal different morphotypes (i.e., late-larval and mid-metamorphic morphotypes). Though feeding on the same prey under the same (aquatic) condition, food processing kinematics differed between late-larval, mid-metamorphic and post-metamorphic morphotypes. Conclusions The food processing mechanism in the Alpine newt changes along with morphology of the feeding apparatus during ontogeny, from a mandible-based to a tongue-based processing mechanism as the changing morphology of the mandible prevents chewing and the tongue allows enhanced protraction. These results could indicate that early tetrapods, in analogy to salamanders, may have developed new feeding mechanisms in their aquatic environment and that these functional innovations may have later paved the way for terrestrial feeding mechanisms.

show abstract

“…Prior studies have hypothesized that, due to their different morphologies, heterochronic morphotypes differ in their feeding performance (capture success-rate) and feeding behavior [11][12][13]. Behavioral studies have shown that paedomorphs tend to have greater aquatic prey capture performance [11,13], but surprisingly, despite diverging prey capture performance and major differences in head morphology, there are only minor differences in prey capture kinematics between heterochronic morphotypes [12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Ontogenetic plasticity in cranial morphology is associated with a functional change in the food processing behavior in Alpine newts

Schwarz

Konow

Porro

et al. 2020

Preprint

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Background: Salamander morphology changes substantially during metamorphosis, prompting the hypothesis that larvae need a different processing mechanism than post-metamorphic adults. Salamandrid newts with facultative metamorphosis are suitable for testing this hypothesis, because paedomorphic and metamorphic adults often coexist in the same population. Facultative paedomorphic newts provide a direct comparison of form-function relationships with specimens of the same species sharing similar body size and feeding on overlapping prey spectra, whilst having divergent food-processing morphologies.Methods: We use high-speed videography to quantify the in vivo movements of key anatomical elements during food processing in paedomorphic and metamorphic Alpine newts ( Ichthyosaura alpestris ). Additionally, we use micro-computed tomography (μCT) to analyze morphological differences in the feeding apparatus of paedomorphic and metamorphic Alpine newts and sort them into late-larval, mid-metamorphic and post-metamorphic morphotypes.Results: Paedomorphic and metamorphic individuals exhibited clear morphological differences of their feeding apparatus. Regardless of the paedomorphic state being externally evident, different paedomorphic specimens can conceal different morphotypes (i.e., late-larval and mid-metamorphic morphotypes). Though feeding on the same prey under the same (aquatic) condition, food processing kinematics differed between late-larval, mid-metamorphic and post-metamorphic morphotypes.Conclusions: While the Alpine Newt still lives in water, food processing mechanism changes along with morphology of the feeding apparatus during ontogeny, from a mandible-based to a tongue-based processing mechanism as the mandible’s changing morphology prevents chewing and the tongue allows enhanced protraction. These results could indicate that early tetrapods, in analogy to salamanders, may have developed new feeding mechanisms in their aquatic environment and that these functional innovations may have later paved the way for terrestrial feeding mechanisms.

show abstract

Same but different: aquatic prey capture in paedomorphic and metamorphic Alpine newts

Cited by 8 publications

References 66 publications

Ontogenetic plasticity in cranial morphology is associated with a change in the food processing behavior in Alpine newts

Ontogenetic plasticity in cranial morphology is associated with a change in the food processing behavior in Alpine newts

Ontogenetic plasticity in cranial morphology is associated with a change in the food processing behavior in Alpine newts

Ontogenetic plasticity in cranial morphology is associated with a functional change in the food processing behavior in Alpine newts

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