Feeding mechanisms in two treefrogs, Hyla nana and Scinax nasicus (Anura: Hylidae).

Instituto de Herpetología, Fundación Miguel Lillo, San Miguel de Tucumán, 4000, Argentina.
Journal of Morphology (Impact Factor: 1.74). 09/2004; 261(2):206-24. DOI: 10.1002/jmor.10239
Source: PubMed


After the description of the chondrocranium, hyobranchial apparatus, associated musculature, buccal apparatus, buccopharyngeal cavity, digestive tract, and gut contents, it was possible to define the feeding modes of Scinax nasicus and Hyla nana tadpoles (Gosner Stages 31-36). Scinax nasicus larvae are "typical" microphagous tadpoles, with keratodonts and robust rostrodonts appropriate for rasping surfaces and mincing of food particles; the buccopharyngeal cavity is equipped with filtering structures and has a conspicuous glandular zone and a highly developed branchial basket. In contrast, H. nana tadpoles have a modified buccal apparatus; the reduction of the buccopharyngeal and branchial basket structures, together with the high lever-arm ratio and the great development of the depressor muscles of the buccal floor are indicative of macrophagous feeding.

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Available from: Esteban O. Lavilla, Apr 16, 2014
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    • "Tadpole feeding is influenced by morphological, physiological and behavioral traits (e.g. Seale & Wassersug, 1979; Vera Candioti, Lavilla & Echeverría, 2004; Pryor & Bjorndal, 2005) as well as microhabitat use (e.g. Rossa-Feres, Jim & Fonseca, 2004; Sousa Filho et al., 2007) and seasonal activity (e.g. "
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    ABSTRACT: Leptodactylus labyrinthicus tadpoles are known predators of anuran eggs and hatchlings, but they are also able to filter-feed in the water column and scrape food off of firm substrates. We evaluated and compared these alternative feeding behaviors in relation to feeding kinematics and the shape of the mouth with high-speed digital imaging. We tested the hypotheses that (1) L. labyrinthicus tadpoles use functionally different feeding kinematics when feeding on alternative food sources and (2) that the jaw sheaths of L. labyrinthicus tadpoles deform less during filter-feeding and substrate grazing compared with more common tadpoles not so specialized for macrophagous carnivory. Our results show that filtering and scraping feeding behaviors differ significantly in both kinematics and shape of the mouth. During filter-feeding, tadpoles display longer gape cycles and attain a narrower maximum gape earlier in the cycle compared with substrate grazing. Jaw deformation during opening and closing phases of the gape cycle is more pronounced during grazing on firm substrates. This deformation contributes to the achievement of a wider maximum gape during feeding. These differences appear to reflect behavioral adjustments by the tadpoles to maximize food intake. Feeding in tadpoles of L. labyrinthicus is not restrained by their typical carnivorous morphology. On the contrary, L. labyrinthicus tadpoles seem to be opportunistic feeders able to obtain nutrients from a variety of food sources by using different feeding strategies.
    Full-text · Article · Apr 2014 · Journal of Zoology
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    • "They have enlarged ceratohyalia, a modification also found in suctorial larvae (Haas and Richards 1998). Even more reduced branchial baskets and larger ceratohyalia are found in macrophagous tadpoles of Hyla nana (Vera Candioti et al. 2004). Larson and Reilly (2003) studied the function of several muscles in aquatic feeding and gill irrigation in tadpoles of Rana catesbeiana. "
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    ABSTRACT: Ziermann, J.M., Infante, C., Hanken, J. and Olsson, L. 2011. Morphology of the cranial skeleton and musculature in the obligate carnivorous tadpole of Lepidobatrachus laevis (Anura: Ceratophryidae). —Acta Zoologica (Stockholm) 00:1–12. Lepidobatrachus laevis (Ceratophryidae: Ceratophryinae) is a bizarre frog endemic to the Chacoan desert of central South America. Its tadpole is an obligate carnivore that can catch and consume live prey nearly its own size. Morphological adaptations associated with this unique feeding mode, including the larval skull anatomy and associated cranial musculature, have only been partly described. We studied the head of Stages 26–27 larvae using gross dissection, immunohistochemistry, and standard histology. Derived features of this tadpole compared to the microphagous, herbivorous larvae of most other anurans include simplified chondrocranial cartilages and very robust jaw muscles. The mm. suspensorio- et quadratoangularis do not take their origin from the processus muscularis of the palatoquadrate, as in most other tadpoles, but instead originate from the corpus of the palatoquadrate caudal to this process. The jaw levators are unusually large. The tadpole of Ceratophrys, another member of the ceratophryine clade, also consumes large animal prey, but its morphology is very different. It probably has evolved independently from a generalized, mainly herbivorous tadpole similar to the larva of Chacophrys, the third ceratophryine genus. Most specialized features of the larval head of Lepidobatrachus laevis are adaptations for ‘megalophagy’—ingestion of whole, very large animal prey.
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    ABSTRACT: This paper provides data on the skeleton, musculature, buccal apparatus, buccopharyngeal cavity and diet of Ceratophrys cranwelli tadpoles, and attempts to contribute to the knowledge of relations between morphology and ecology in anuran larvae. Both in morphological characters and feeding habits, these tadpoles are very similar to other species within the genus. They possess many of the structural features usually found in predaceous tadpoles: strong, keratinized jaw sheaths and keratodonts, reduced buccal papillation, high values of in-lever arm proportion and buccal floor area, well-developed ceratohyals, and hypertrophied jaw muscles. Food sources consist of other tadpoles, microcrustaceans, larvae of insects, plant fragments, as well as rotifers and microalgae. As facultative carnivores, they are likely to play an important role in regulating the aquatic communities of the ephemeral ponds where they develop.
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