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Oliveira REMD, Attademo FLN, Sousa ACFCD, Magalhães MDS, Oliveira RMD, de Moura CEB, Silva AR, Pereira AF, Fragoso ABL, Silva FJDL, Oliveira MFD. Oropharyngeal cavity floor morphology in Eretmochelys imbricata (Testudines: Cheloniidae) hatchlings and evolutionary implications. Anat Rec (Hoboken) 2023; 306:343-353. [PMID: 36054069 DOI: 10.1002/ar.25061] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Revised: 08/15/2022] [Accepted: 08/17/2022] [Indexed: 01/25/2023]
Abstract
Morphological studies of the oropharyngeal cavity of chelonians have become an interesting tool in the understanding of evolutionary processes associated with feeding habits in aquatic animals and the transition from aquatic to terrestrial forms. In this context, the aim of the present study was to describe the oropharyngeal cavity floor morphology of hawksbill sea turtle (Eretmochelys imbricata) hatchlings. Ten dead hatchlings of undefined sex were obtained from nests hatched on the coast of the state of Rio Grande do Norte, Brazil. The heads of each specimen were fixed, dissected, and analyzed at the macroscopic and microscopic levels. The oropharyngeal cavity floor of the hawksbill sea turtle hatchlings is formed by the tongue, pharynx, floor muscles, and hyolingual skeleton, delimited in the rostral and lateral directions by a keratinized beak, called the rhamphotheca, and in the caudal region at the limit between the pharynx and the esophagus. The tongue muscles and the muscles that support the floor of the oral cavity comprise the following: m. hypoglossohyoideus, m. hypoglossoglossus, m. hyoglossus, m. genioglossus, m. constrictor laryngis, m. geniohyoideus pars lateralis, and m. intermandibularis. The oropharyngeal cavity floor mucosa is formed by keratinized stratified squamous epithelium and the lamina propria is formed by loose connective tissue. The floor mucosa is devoid of taste buds. We believe that the basic oropharyngeal cavity floor characteristics in hawksbill sea turtle hatchlings may comprise indications that these animals are plesiomorphic and that semiaquatic and terrestrial turtles may have undergone adaptations to feed out of water.
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Affiliation(s)
- Radan Elvis Matias de Oliveira
- Programa de Pós-Graduação em Ciência Animal (PPGCA), Universidade Federal Rural do Semi-Árido (UFERSA), Mossoró, Rio Grande do Norte, Brazil.,Centro de Estudos e Monitoramento Ambiental (CEMAM), Areia Branca, Rio Grande do Norte, Brazil.,Projeto Cetáceos da Costa Branca (PCCB), Universidade do Estado do Rio Grande do Norte (UERN), Mossoró, Rio Grande do Norte, Brazil
| | - Fernanda Loffler Niemeyer Attademo
- Centro de Estudos e Monitoramento Ambiental (CEMAM), Areia Branca, Rio Grande do Norte, Brazil.,Centro Universitário Internacional (UNINTER), Curitiba, Paraná, Brazil
| | - Ana Caroline Freitas Caetano de Sousa
- Departamento de Ciências Animais, Laboratório de Morfofisiologia Animal Aplicada (LABMORFA), Universidade Federal Rural do Semi-Árido (UFERSA), Mossoró, Rio Grande do Norte, Brazil
| | | | - Rysónely Maclay de Oliveira
- Programa de Pós-Graduação em Ciência Animal (PPGCA), Universidade Federal Rural do Semi-Árido (UFERSA), Mossoró, Rio Grande do Norte, Brazil.,Projeto Cetáceos da Costa Branca (PCCB), Universidade do Estado do Rio Grande do Norte (UERN), Mossoró, Rio Grande do Norte, Brazil
| | - Carlos Eduardo Bezerra de Moura
- Programa de Pós-Graduação em Ciência Animal (PPGCA), Universidade Federal Rural do Semi-Árido (UFERSA), Mossoró, Rio Grande do Norte, Brazil
| | - Alexandre Rodrigues Silva
- Programa de Pós-Graduação em Ciência Animal (PPGCA), Universidade Federal Rural do Semi-Árido (UFERSA), Mossoró, Rio Grande do Norte, Brazil
| | - Alexsandra Fernandes Pereira
- Programa de Pós-Graduação em Ciência Animal (PPGCA), Universidade Federal Rural do Semi-Árido (UFERSA), Mossoró, Rio Grande do Norte, Brazil
| | - Ana Bernadete Lima Fragoso
- Centro de Estudos e Monitoramento Ambiental (CEMAM), Areia Branca, Rio Grande do Norte, Brazil.,Projeto Cetáceos da Costa Branca (PCCB), Universidade do Estado do Rio Grande do Norte (UERN), Mossoró, Rio Grande do Norte, Brazil
| | - Flávio José de Lima Silva
- Centro de Estudos e Monitoramento Ambiental (CEMAM), Areia Branca, Rio Grande do Norte, Brazil.,Projeto Cetáceos da Costa Branca (PCCB), Universidade do Estado do Rio Grande do Norte (UERN), Mossoró, Rio Grande do Norte, Brazil.,Programa Regional de Pós-Graduação em Desenvolvimento e Meio Ambiente (PRODEMA), Universidade Federal do Rio Grande do Norte (UFRN), Natal, Rio Grande do Norte, Brazil
| | - Moacir Franco de Oliveira
- Programa de Pós-Graduação em Ciência Animal (PPGCA), Universidade Federal Rural do Semi-Árido (UFERSA), Mossoró, Rio Grande do Norte, Brazil
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Zuwała K, Jakubowski M. Structural diversification of the gustatory organs during metamorphosis in the alpine newt Triturus alpestris. J Anat 2007; 211:371-5. [PMID: 17578451 PMCID: PMC2375809 DOI: 10.1111/j.1469-7580.2007.00758.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/03/2007] [Indexed: 11/30/2022] Open
Abstract
Gustatory organs of the taste bud type occur in the epithelial lining of the oropharyngeal cavity of alpine newt larvae. They resemble the taste buds of bony fish, both in appearance (as revealed by scanning electron microscopy) and in detailed internal structure (seen on transmission electron micropscopy). During metamorphosis, at stage 55 of development, the secondary tongue (i.e. the soft tongue) is well formed and the anlages of taste discs are clearly apparent. Somewhat later, taste discs also appear in the epithelial lining outside the tongue, paralleling the disappearance of the taste buds. Well-developed taste discs of the newt differ from taste buds mainly by their structurally diversified set of 'associate cells' (mucous, wing and glial cells), which have no synaptic contact with nerve fibres. These cells accompany the neurosensory cellular components of the taste disc, i.e. the taste receptor cells and basal cells. This indicates that gustatory organs in metamorphosed newts, regardless of their small dimensions, fulfil the criteria established for taste discs previously defined in other Caudata and Anura species. Therefore, in the development of the newt there are two subsequent types of gustatory organs and two generations of the tongue: primary, in the larvae, and secondary, in metamorphosed animals.
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Affiliation(s)
- Krystyna Zuwała
- Department of Comparative Anatomy, Jagiellonian University, Kraków, Poland.
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Zuwała K, Kato S, Jakubowski M. Two generations of the tongue and gustatory organs in the development of Hynobius dunni Tago. J Anat 2002; 201:91-7. [PMID: 12171480 PMCID: PMC1570895 DOI: 10.1046/j.1469-7580.2002.00076.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/20/2002] [Indexed: 11/20/2022] Open
Abstract
In the development of Hynobius dunni there are two consecutive generations of the tongue and two generations of gustatory organs (taste buds and taste disks). The anlage of the developing secondary tongue appears just in front of the free ending of the primary tongue beginning at the larval developmental stage 62. From stage 67, a gradual reduction in the anterior part of the gill skeleton that supports the primary tongue occurs as the developing secondary tongue replaces the primary one. The lining of the entire oropharyngeal cavity of larvae contains only gustatory organs of the taste bud (TB) type. In younger larvae, the sensory area of a TB has a diameter of between 10 and 13 microm, while in older larvae, TBs reach 16-18 microm in diameter. After metamorphosis, some gustatory organs in the secondary tongue with a sensory area of 26-36 microm in diameter appear. In older animals they may reach as much as 56-71 microm. In other regions of the oropharyngeal epithelium than the tongue, these organs have an ellipsoid shape with a major axis of about 50 microm. On the basis of the cytomorphological criteria established previously, these organs were designated as taste disks. Thus, the presence of two generations of gustatory organs is characteristic of some urodeles, as well as frogs.
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Affiliation(s)
- K Zuwała
- Jagiellonian University, Kraków, Poland.
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