Diets of Amazonian Crocodilians

Magnusson, William E.; Silva, Eduardo Vieira da; Lima, Albertina P.

doi:10.2307/1564468

Cited by 116 publications

(108 citation statements)

References 9 publications

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“…For example, in very large (3.0ϩ m) animals, mammals may constitute 81.4% of diet by mass, while fish only constitute 15.1% (Wolfe et al, 1987), consistent with Dodson's (1975) suggestion, based on growth studies of the skull in this species, that allo-metric changes in cranial structure have important effects on prey choice among crocodilians [this was also discussed by Hutton (1987) regarding Crocodylus niloticus]. Magnusson et al (1987), however, suggest that diet among Amazonian crocodilians is a function of habitat selection, rather than a function of cranial mechanics. Still, they attribute the relatively large amount of terrestrial vertebrates eaten by Paleosuchus trigonatus to selection for terrestrial prey based on the fact that even small individuals show a bias toward terrestrial vertebrate prey, while other species only begin to acquire terrestrial vertebrates at larger body sizes.…”

Section: Does the Crocodilian Skull Represent A Functional Compromisesupporting

confidence: 74%

Biomechanics of the rostrum in crocodilians: A comparative analysis using finite‐element modeling

McHenry¹,

Clausen²,

Daniel³

et al. 2006

Anat. Rec.

160

251

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This article reports the use of simple beam and finite-element models to investigate the relationship between rostral shape and biomechanical performance in living crocodilians under a range of loading conditions. Load cases corresponded to simple biting, lateral head shaking, and twist feeding behaviors. The six specimens were chosen to reflect, as far as possible, the full range of rostral shape in living crocodilians: a juvenile Caiman crocodilus, subadult Alligator mississippiensis and Crocodylus johnstoni, and adult Caiman crocodilus, Melanosuchus niger, and Paleosuchus palpebrosus. The simple beam models were generated using morphometric landmarks from each specimen. Three of the finite-element models, the A. mississippiensis, juvenile Caiman crocodilus, and the Crocodylus johnstoni, were based on CT scan data from respective specimens, but these data were not available for the other models and so these-the adult Caiman crocodilus, M. niger, and P. palpebrosus-were generated by morphing the juvenile Caiman crocodilus mesh with reference to three-dimensional linear distance measured from specimens. Comparison of the mechanical performance of the six finite-element models essentially matched results of the simple beam models: relatively tall skulls performed best under vertical loading and tall and wide skulls performed best under torsional loading. The widely held assumption that the platyrostral (dorsoventrally flattened) crocodilian skull is optimized for torsional loading was not supported by either simple beam theory models or finite-element modeling. Rather than being purely optimized against loads encountered while subduing and processing food, the shape of the crocodilian rostrum may be significantly affected by the hydrodynamic constraints of catching agile aquatic prey. This observation has important implications for our understanding of biomechanics in crocodilians and other aquatic reptiles. Anat Rec Part A, 288A:827-849, 2006. © 2006 Key words: crocodiles; skull biomechanics; finite-element analysis; feeding; hydrodynamics; aquatic/marine tetrapods; comparative modelingCrocodilians have long been used as a model for interpreting the paleobiology of fossil species. The range of overall head shape and dentition in living taxa is reasonably broad (Mook, 1921), and observed correlations between these anatomical features and feeding ecology in crocodilians (Iordansky, 1973;Langston, 1973;Aoki, 1977;Van Drongelen and Dullemeijer, 1982;Busbey, 1989) have formed the bases for hypotheses of feeding paleoecology in a large array of

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Section: Does the Crocodilian Skull Represent A Functional Compromisesupporting

confidence: 74%

Biomechanics of the rostrum in crocodilians: A comparative analysis using finite‐element modeling

McHenry¹,

Clausen²,

Daniel³

et al. 2006

Anat. Rec.

160

251

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“…Our interest in analyzing the genetic variability of these species arises not only from their economic and ecological importance, as emphasized in previous studies, but also from the paucity of studies on their biology, from the syntopic and taxonomic difficulties in their identification, and from the fact that Mj and Ma have been introduced into our region (Kensley and Walker, 1982;Magnusson et al, 1987).…”

Section: Discussionmentioning

confidence: 99%

Genetic polymorphism, molecular characterization and relatedness of Macrobrachium species (Palaemonidae) based on RAPD-PCR

Guerra

Lima²,

Taddei³

et al. 2010

Genet. Mol. Res.

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ABSTRACT. The prawn genus Macrobrachium belongs to the family Palaemonidae. Its species are widely distributed in lakes, reservoirs, floodplains, and rivers in tropical and subtropical regions of South America. Globally, the genus Macrobrachium includes nearly 210 known species, many of which have economic and ecological importance. We analyzed three species of this genus (M. jelskii, M. amazonicum and M. brasiliense) using RAPD-PCR to assess their genetic variability, genetic structure and the phylogenetic relationship between them and to look for molecular markers that enable separation of M. jelskii and M. amazonicum, which are closely related syntopic species. Ten different random decamer primers were used for DNA amplification, yielding 182 fragments. Three of these fragments were monomorphic and exclusive to M. amazonicum or M. jelskii and can be used as specific molecular markers to identify and separate these two species. Similarity indices and a phylogenetic tree showed that M. amazonicum and M. jelskii are closest to each other, while M. brasiliense was the most differentiated species among them; this may be attributed to the different habitat conditions to which these species have been submitted. This information will be useful for further studies on these important crustacean species.

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“…Other authors have also reported fish as the main component of the diet for crocodilians (Delany & Abercrombie 1986, Thorbjarnarson 1993, Tucker et al 1996. Differences on diet might depend on the type of habitat (Delany & Abercrombie 1986, Magnusson et al 1987), but we suspect that findings of CasasAndreu & Barrios (2003) are biased by the method used (feces analysis instead of stomach contents).…”

Section: Discussionmentioning

confidence: 77%

Feeding habits of the american crocodile, crocodylus acutus (cuvier, 1807) (reptilia: crocodylidae) in the Southern Coast of Quintana Roo, México

Villegas

Schmitter‐Soto

2008

AZM

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RESUMENEntre enero y septiembre de 2006 se capturaron 21 cocodrilos (Crocodylus acutus) y se recapturaron seis en cuatro sistemas lagunares de la costa sur de Quintana Roo para analizar los contenidos estomacales. Las presas encontradas en el contenido estomacal se dividieron en cinco grupos y se realizaron análisis basados en la frecuencia y en el volumen. Las presas encontradas en orden de importancia fueron peces, crustáceos, aves, mamíferos e insectos. La dieta de los cocodrilos cambió considerablemente de acuerdo con el tamaño corporal de los individuos. Los cocodrilos adultos agregaron a su dieta presas de mayor talla como aves y mamíferos. Peces y crustáceos estuvieron representados en la dieta de individuos de todas las clases de tamaño, demostrando la importancia que estas presas tienen en la dieta de C. acutus. Palabras clave: Crocodylus acutus, Quintana Roo, contenido estomacal, hábitos alimentarios. ABSTRACTBetween January and September 2006, 21 crocodiles (Crocodylus acutus) were captured and six were recaptured in four lagoons located in the southern coast of Quintana Roo. Stomach contents were obtained in order to identify prey items, which were analyzed by the frequency and volume method. In decreasing order of importance, prey items were fish, crustaceans, birds, mammals and insects. Diet of crocodiles changed considerably according to their body size. Adult crocodiles added larger preys (birds and mammals) to their diet; fish and crustaceans were present in the diet at all sizes, thus showing the importance of these prey in the diet of American crocodiles.

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Diets of Amazonian Crocodilians

Cited by 116 publications

References 9 publications

Biomechanics of the rostrum in crocodilians: A comparative analysis using finite‐element modeling

Biomechanics of the rostrum in crocodilians: A comparative analysis using finite‐element modeling

Genetic polymorphism, molecular characterization and relatedness of Macrobrachium species (Palaemonidae) based on RAPD-PCR

Feeding habits of the american crocodile, crocodylus acutus (cuvier, 1807) (reptilia: crocodylidae) in the Southern Coast of Quintana Roo, México

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