INVESTIGADORES
FERNANDEZ Marta Susana
congresos y reuniones científicas
Título:
SALT GLANDS IDENTIFIED IN A LATE CRETACEOUS POLYCOTYLID
Autor/es:
MARTIN, Y & M. FERNÁNDEZ
Lugar:
Bristol, Inglaterra
Reunión:
Congreso; 69 th Anual Meeting Society of Vertebrate Paleontology; 2009
Resumen:
In 2007, a new polycotylid plesiosaur, Pahasapasaurus haasi, from western South Dakota
was described. The specimen is housed in the Adams Museum, Deadwood (AMM 98.1.1),
and was derived from the early late Cenomanian Orman Lake Member at the base of the
Greenhorn Limestone north of the Black Hills in Butte County. The holotype is represented
by a relatively complete cranium, which is broken away in antorbital area, revealing paired
natural casts of lobulated structures preserved in concretionary ferruginous marl. These
structures are clearly separated from the exposed infilling of the nasal capsule and must
have been covered in the living marine reptile dorsally by extensions of the maxillae, the
premaxillae, and probably the anterior frontals. The position and lobate structures resemble
salt glands of other extant marine reptiles like the iguana Amblyrhynchus and do not
resemble normal sedimentological structures. Reptiles that have reinvaded the marine habitat
require a means to remove the excess of salt to prevent lethal osmotic dehydration. Such salt
glands in plesiosaurs had been expected, but this specimen possesses the first actual evidence
for these structures.Pahasapasaurus haasi, from western South Dakota
was described. The specimen is housed in the Adams Museum, Deadwood (AMM 98.1.1),
and was derived from the early late Cenomanian Orman Lake Member at the base of the
Greenhorn Limestone north of the Black Hills in Butte County. The holotype is represented
by a relatively complete cranium, which is broken away in antorbital area, revealing paired
natural casts of lobulated structures preserved in concretionary ferruginous marl. These
structures are clearly separated from the exposed infilling of the nasal capsule and must
have been covered in the living marine reptile dorsally by extensions of the maxillae, the
premaxillae, and probably the anterior frontals. The position and lobate structures resemble
salt glands of other extant marine reptiles like the iguana Amblyrhynchus and do not
resemble normal sedimentological structures. Reptiles that have reinvaded the marine habitat
require a means to remove the excess of salt to prevent lethal osmotic dehydration. Such salt
glands in plesiosaurs had been expected, but this specimen possesses the first actual evidence
for these structures.Amblyrhynchus and do not
resemble normal sedimentological structures. Reptiles that have reinvaded the marine habitat
require a means to remove the excess of salt to prevent lethal osmotic dehydration. Such salt
glands in plesiosaurs had been expected, but this specimen possesses the first actual evidence
for these structures.