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Salt Gland (salt + gland)
Selected AbstractsSalt glands in a Tithonian metriorhynchid crocodyliform and their physiological significanceLETHAIA, Issue 4 2000Marta Fernández Our knowledge of Mesozoic tetrapods is based mainly on osteological evidence. The discussion of the evolution of any homeostatic system is highly speculative because direct non-osteological evidence is uncommon. Here we report an extraordinarily well-preserved cast of a pair of lobulated protuberances in the skull of the marine metriorhynchid crocodiliform Geosaurus from the Tithonian (Jurassic) of Patagonia (Argentina). These protuberances are interpreted as representing salt glands. Based on their topology, these glands are identified as the nasals. Optimization of this character on a phylogenetic tree permits us to infer the ancestral condition for archosaurs. The relationship between salt gland and diet is also analysed. The presence of hypertrophied salt glands in the skull of Geosaurus suggests that as early as 140 million years ago, some Mesozoic marine reptiles had evolved an extra-renal osmoregulatory system. This achievement was an important clue in the successful colonization of marine environments. Salt glands preclude the risk of lethal dehydration and allow marine reptiles to include an important amount of invertebrates in their diet. [source] Expression of the Artemia trachealess gene in the salt gland and epipodEVOLUTION AND DEVELOPMENT, Issue 5 2002Brian Mitchell SUMMARY The Drosophila trachealess gene encodes a basic-helix-loop-helix-PAS transcription factor that controls the formation of the trachea and salivary duct. An ortholog of trachealess was identified in the brine shrimp, Artemia franciscana, and was shown to be highly conserved by sequence identity. Expression of Artemia trachealess was observed at two sites during development: the naupliar salt gland and the juvenile thoracic epipod. These two organs function at their respective times of development in osmoregulation, an important aspect of brine shrimp physiology. This extends the range of putative functions of trachealess to include formation of osmoregulatory, respiratory, and ductile organs. [source] Salt glands in a Tithonian metriorhynchid crocodyliform and their physiological significanceLETHAIA, Issue 4 2000Marta Fernández Our knowledge of Mesozoic tetrapods is based mainly on osteological evidence. The discussion of the evolution of any homeostatic system is highly speculative because direct non-osteological evidence is uncommon. Here we report an extraordinarily well-preserved cast of a pair of lobulated protuberances in the skull of the marine metriorhynchid crocodiliform Geosaurus from the Tithonian (Jurassic) of Patagonia (Argentina). These protuberances are interpreted as representing salt glands. Based on their topology, these glands are identified as the nasals. Optimization of this character on a phylogenetic tree permits us to infer the ancestral condition for archosaurs. The relationship between salt gland and diet is also analysed. The presence of hypertrophied salt glands in the skull of Geosaurus suggests that as early as 140 million years ago, some Mesozoic marine reptiles had evolved an extra-renal osmoregulatory system. This achievement was an important clue in the successful colonization of marine environments. Salt glands preclude the risk of lethal dehydration and allow marine reptiles to include an important amount of invertebrates in their diet. [source] CT and Cross-sectional Anatomy of the Normal Head of the Loggerhead Sea Turtle (Caretta caretta)ANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 2005A. Arencibia The objective of this study is to describe the CT anatomy of the normal loggerhead sea turtle (Caretta caretta) head using three loggerhead sea turtle heads. CT imaging was performed using the following parameters: K.v.: 120 mAs: 220, and a soft-tissue window (WW 1880, WL 465): Transverse and sagittal CT images were obtained. Detailed anatomy of the head was acquired with the sagittal and transverse series. The heads were frozen and then sectioned using an electric saw, to compare them with the CT images. In CT, the grey scale is directly related to the radiation attenuation of the head structures. The skull and hyoid bones, and the lower jaw were easily identifiable due to the high CT density image compared to adjacent or surrounding structures such as the respiratory system, oral cavity, oesophagus and cranial cavity that appeared as a low opacity. The nervous structures, salt gland, eyeball, ramphoteca structure and different muscles of the head had an intermediate CT density and appeared grey. CT images of the loggerhead sea turtle head provided excellent detail of clinically relevant anatomy and correlated well with corresponding gross specimens. CT of the head has considerable advantages over other techniques: CT provides excellent spatial resolution and good discrimination between bone and soft tissue, and the structures are viewed without superimposition. The planimetric or sectional anatomy of the head allows a correct morphologic and topographic evaluation of the anatomic structures, which is a useful tool for the identification of the CT images. With developing technology, CT imaging may soon become more readily available for exotic animals imaging. In the same way, we consider it quite useful to be able to establish some references on head, in order to scan only selected parts during a clinical or experimental approach. The information presented in this communication should serve as an initial reference to evaluate CT images of the loggerhead sea turtle head and to assist interpretation of lesions of this region. [source] The internal cranial anatomy of the Plesiosauria (Reptilia, Sauropterygia): evidence for a functional secondary palateLETHAIA, Issue 4 2006Marie-Céline Buchy In the late 19th Century, the choanae (or internal nares) of the Plesiosauria were identified as a pair of palatal openings located rostral to the external nares, implying a rostrally directed respiratory duct and air path inside the rostrum. Despite obvious functional shortcomings, this idea was firmly established in the scientific literature by the first decade of the 20th Century. The functional consequences of this morphology were only re-examined by the end of the 20th Century, leading to the conclusion that the choanae were not involved in respiration but instead in underwater olfaction, the animals supposedly breathing with the mouth agape. Re-evaluation of the palatal and internal cranial anatomy of the Plesiosauria reveals that the traditional identification of the choanae as a pair of fenestrae situated rostral to the external nares appears erroneous. These openings more likely represent the bony apertures of ducts that lead to internal salt glands situated inside the maxillary rostrum. The ,real' functional choanae (or caudal interpterygoid vacuities), are situated at the caudal end of the bony palate between the sub-temporal fossae, as was suggested in the mid-19th Century. The existence of a functional secondary palate in the Plesiosauria is therefore strongly supported, and the anatomical, physiological, and evolutionary implications of such a structure are discussed. [source] Salt glands in a Tithonian metriorhynchid crocodyliform and their physiological significanceLETHAIA, Issue 4 2000Marta Fernández Our knowledge of Mesozoic tetrapods is based mainly on osteological evidence. The discussion of the evolution of any homeostatic system is highly speculative because direct non-osteological evidence is uncommon. Here we report an extraordinarily well-preserved cast of a pair of lobulated protuberances in the skull of the marine metriorhynchid crocodiliform Geosaurus from the Tithonian (Jurassic) of Patagonia (Argentina). These protuberances are interpreted as representing salt glands. Based on their topology, these glands are identified as the nasals. Optimization of this character on a phylogenetic tree permits us to infer the ancestral condition for archosaurs. The relationship between salt gland and diet is also analysed. The presence of hypertrophied salt glands in the skull of Geosaurus suggests that as early as 140 million years ago, some Mesozoic marine reptiles had evolved an extra-renal osmoregulatory system. This achievement was an important clue in the successful colonization of marine environments. Salt glands preclude the risk of lethal dehydration and allow marine reptiles to include an important amount of invertebrates in their diet. [source] | ||||||||||