Ontogenetic development of the oral apparatus and oropharyngeal cavity in bullfrog tadpoles (Lithobates catesbeianus, Shaw 1802)

Publication date: Available online 20 February 2019

Source: Archives of Oral Biology

Author(s): Laura Satiko Okada Nakaghi, Veronica Regina Lobato Oliveira-Bahia, Marta Verardino De Stefáni, João Martins Pizauro, Kifayat Ullah Khan, Beatrice Ingrid Macente, Cleber Fernando Menegasso Mansano

Abstract

Objective

The present study aimed to describe the morphology of oral apparatus and oral cavity of bullfrog tadpoles during their development and metamorphosis.

Design

The oral apparatus and oropharyngeal cavity of tadpoles from hatching up to metamorphosis stage was dissected for further analysis. These structures were fixed in Karnovsky solution, afterwards in osmium tetroxide and metalized in palladium gold and electron-micrographed using the scanning electron microscope.

Results

The development of oral apparatus started with the formation and keratinization of the jaw sheaths and labial teeth followed by the formation of marginal and sub-marginal papillae. Degeneration of oral apparatus and formation of mouth was observed during metamorphosis. From stage-42 (metamorphic climax) to stage-43, the jaw sheath and labial tooth rows were disappeared progressively while the size and number of labial papillae were decreased. At stage-44, mouth formation started with the development of anterior and posterior labium though the labial papillae were still present. At stage-45 and 46, mouth was already formed, being very similar to the adult and characterized by the progressive increase in size.

Conclusion

The sequence of events that happen during the development of oral apparatus of Lithobates catesbeianus Shaw, 1802 tadpoles follows the same pattern as occur in other anuran species but metamorphic atrophy of the oral apparatus follows the sequence of morphogenesis.

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