TY - JOUR
T1 - Supernumerary thyroid glands of Pleurodeles waltl (Caudata, Salamandridae)
AU - Gozzo, Stefano
AU - Taglioni, Alessandra
AU - Casetti, Rita
AU - Meloni, Monica
AU - Bagnoli, Claudio
AU - Monaco, Vincenzo
PY - 1996
Y1 - 1996
N2 - The size and the number of thyroid masses in medium larval, climax, and postmetamorphic developmental stages of Pleurodeles waltl were examined in histological sections. Morphological data were also obtained from postmetamorphic specimens, that had been treated for a year with thiourea. In addition to a pair of lateral thyroid glands that developed during larval stages, microscopic examination revealed the presence of two or three supernumerary thyroid glands that were very small in the climax stage, but increased appreciably in size and development in 1-year-old postmetamorphic animals. Structural modifications in the supernumerary thyroids similar to those observed in the lateral thyroid glands were observed in thiourea-exposed, postmetamorphic animals. These supernumerary thyroids can be classified as one or two thyroid glands located in the anterior medial sagittal region of the lower jaw, and one posterior thyroid gland located in a left parasagittal region near the pericardial sac. On the basis of the thyroid control on body development and growth in the postmetamorphic stage, reported in other studies, including our own, and of the postmetamorphic morphology of the supernumerary thyroid glands in P. waltl, an evolutive adaptation of the thyroid system to the habitat of this species is hypothesized.
AB - The size and the number of thyroid masses in medium larval, climax, and postmetamorphic developmental stages of Pleurodeles waltl were examined in histological sections. Morphological data were also obtained from postmetamorphic specimens, that had been treated for a year with thiourea. In addition to a pair of lateral thyroid glands that developed during larval stages, microscopic examination revealed the presence of two or three supernumerary thyroid glands that were very small in the climax stage, but increased appreciably in size and development in 1-year-old postmetamorphic animals. Structural modifications in the supernumerary thyroids similar to those observed in the lateral thyroid glands were observed in thiourea-exposed, postmetamorphic animals. These supernumerary thyroids can be classified as one or two thyroid glands located in the anterior medial sagittal region of the lower jaw, and one posterior thyroid gland located in a left parasagittal region near the pericardial sac. On the basis of the thyroid control on body development and growth in the postmetamorphic stage, reported in other studies, including our own, and of the postmetamorphic morphology of the supernumerary thyroid glands in P. waltl, an evolutive adaptation of the thyroid system to the habitat of this species is hypothesized.
KW - Metamorphosis
KW - Pleurodeles waltl
KW - Thiourea
KW - Thyroid follicles
KW - Thyroid glands
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M3 - Article
AN - SCOPUS:7944223057
VL - 63
SP - 207
EP - 214
JO - Bolletino di zoologia
JF - Bolletino di zoologia
SN - 1125-0003
IS - 3
ER -