Heterodosaurio patagónico

Discovered by: unknown
Studied by: A. M. Báez and C. Marcicano (it is currently being studied)
Period: Late Triassic (210 million years)
Length: 1 meter
Weight: 10 Kg.
Location: Laguna Colorada, Santa Cruz Province.

Elements found (one specimen)
1- Incomplete jawbone with related teeth.

Main characteristics: These small Ornithopods were found in layers belonging to the Early Jurassic in South Africa, in the South western area of the USA and perhaps in China. Their divergence and dispersion along the world was an early one, favored by the Pangea Continent. Their most surprising feature is the great quantity of specialized teeth. This was not very usual for reptiles, specially the canine which was very useful, to eat or to attack in territorial fights.

Paleo-Environment: They lived in a pluvial area, with little flora, due to the volcanoes activities, but with Neocalamites, "ferns with seeds", Dicroidium, and Osmudales ferns. Among the fauna, we can mention the Prosauropods like young Mussaurus and some adult Plateosaurus.

Kritosaurus australis

Discovered by: an expedition of the Museo Argentino de Ciencias Naturales "Bernardino Rivadavia" (Argentinean Museum of Natural Sciences), headed by Dr. José F. Bonaparte in 1984.
Studied by: José Bonaparte, Frenchi, J. Powell and Sepúlveda, 1984.
Period: Late Cretaceous (80 million years)
Length: 10 meters long and 3 meters high.
Location: Los Alamitos Formation, Río Negro Province.
Exhibition: Museo Argentino de Ciencias Naturales "Bernardino Rivadavia" (Argentinean Museum of Natural Sciences), Buenos Aires City.

Elements found:
1- Pelvis
2- Fragment of a femur
3- Femur (1 meter)
4- An incomplete skull
5- Right coracoids
6- Fragment of a skull
7- Fragment of a breastbone
8- Left scapular
9- Part of a denture

Museo Argentino de Ciencias Naturales	© Argentina On View Museo Argentino de Ciencias Naturales

Main characteristics: It is based on several incomplete skeletons from Los Alamitos Formation. The feature that made them different was the prolongation of the anterior part of the face, forming a wide and plain muzzle with a beak without teeth similar to a duck one. The morphology of the three bones of their pelvis, coincides very well with those of the Kritosaurus Navajovius from North America. There are some differences in their extremities' bones. The Kritosaurus Australis skull has several differences with the other species of Kritosaurus ones. Their breastbones, scapulars and humerus have a different morphology.
It is thought that they colonized South America very quickly. Obviously, it was a successful colonization since they went through the whole Continent from north to south, reaching latitudes relatively high in the central Patagonia.

Internet:
dinosauricon.com/genera/kritosaurus.html
www.dinodata.net/Dd/Namelist/Tabk/K022.htm
www.intelradio.com.ar/dinosaurios/kritosurus.htm

Lagosuchus talampayensis

Discovered by: Professor Romer in 1971.
Studied by: José F. Bonaparte, 1975.
Period: Middle Triassic (225 million years)
Length: 45 cm.
Location: Cañón de Talampaya, La Rioja Province.
Exhibition: Museo Argentino de Ciencias Naturales "Bernardino Rivadavia" (Argentinean Museum of Natural Sciences), Buenos Aires City and Lillo Foundation Institute, Universidad Nacional de Tucumán (Tucumán National University), Tucumán Province.

Elements found: (4 skeletons)
1- Cervical vertebras
2- Fragments of the skull
3- Left scapular coracoids
4- Left humerus
5- Left radio and ulna
6- Right femur
7- Left foot
8- Astragalus and heels
9- Tibias and fibulas

Main characteristics: It is known due to 4 skeletons, two of them are very complete ones, but their skulls are incomplete ones. According to José F. Bonaparte (1975), Lagosuchus was the only one Triassic form that could be regarded as a potential ancestor of the saurian dinosaurs. It is said that it shows morphological transitional features in its pelvis structure, and in some other parts of its body (pelvis, astragalus, some vertebras, back extremities, forelegs). Lagosuchus was not a primitive saurian dinosaur, but some parts of its body developed some anatomical features that would indicate an advance towards the development of the first saurian.

Internet:
www.intelradio.com.ar/dinosaurios/lagosuchus.htm
www.dinodata.net/Dd/Namelist/Tabl/L021.htm
dinosauricon.com/genera/lagosuchus.html

Mussaurus patagonicus

Discovered by: A commission of the Tucumán National University, financed by National Geographic, 1976.
Studied by: José F. Bonaparte and M. Vince, 1979.
Period: Late Triassic (205 million years).
Length: 3 meters
Location: El Tranquilo Formation, Santa Cruz Province.
Exhibition: Facultad de Ciencias Naturales de la Universidad Nacional de Tucumán (Natural Sciences College of the Tucumán National University), Tucumán City.

Elements found (young specimens):
1- Skulls
2- Jaws
3- Teeth (long and cylindrical ones)
4- Cervical vertebras
5- Back extremities
6- Forelegs (not the holotype)

Main characteristics: Mussaurus was probably a member of the Plateosauridae family, in spite of the fact that the skull's morphology doesn't favor a sure identification. However, and according to what we know about the adult specimen it would be a Plateosaurian. It is represented by several newly born specimens, found altogether and associated to two eggs. Probably they belonged to the same nest.
The biological information that they provide is very important because it suggests that the young specimens stayed for some time in the nest, probably with their parents. The presence of this Prosauropod in the south of the Patagonia, suggests that their geographic distribution in South America was a very important and long one.

Internet:
dinosauricon.com/genera/mussaurus.html
www.dinodata.net/Dd/Namelist/Tabm/M146.htm
www.intelradio.com.ar/dinosaurios/pocainformacion4.htm

Patagonykus puertai

Discovered by: Fernando Novas in 1996.
Period: Late Cretaceous (95 million years).
Length: 2 meters.
Location: Sierra del Portezuelo, Neuquén Province.
Exhibition: Carmen Funes Museum, Plaza Huincul.

Main characteristics: It was a Theropod with feathers, it fed insects. It had short arms and only one finger with a strong claw. Its fossils were found to 20 Km to the west of Cutral-Có, and Plaza Huincul Cities. It is regarded as a non-flying primitive bird like as a ñandú (a kind of little ostrich that lives in the argentinean Patagonia and the pampa).

Internet:
dinosauricon.com/genera/patagonykus.html
www.dinodata.net/Dd/Namelist/Tabp/P049.htm
www.intelradio.com.ar/dinosaurios/patagonikus.htm

Patagosaurus fariasi

Discovered by: Ricardo Farias.
Studied by: José F. Bonaparte in 1979 of the Museo Argentino de Ciencias Naturales "Bernardino Rivadavia" (Argentinean Museum of Natural Sciences), and later on by Rodolfo Coria paleontologist of the Carmen Funes Museum, Plaza Huincul.
Period: Middle Jurassic (165 million years)
Length: 15 meters long, and 7 meters high up to the head.
Weight: 10 to 40 tons.
Location: Cerro Cóndor, Chubut Province.
Exhibition: Museo Argentino de Ciencias Naturales "Bernardino Rivadavia" ( Argentinean Museum of Natural Sciences), Buenos Aires City.

Elements found:
1- Femur (1.30 meters long) and three younger specimens ones. One of them with a femur of 50 cm, and a shorter one too.
2- Jawbone (1)
3- Some teeth, and the inferior part of a jawbone. The alveolar series has 4 wide sockets in the jawbone and 11 or 12 in the inferior jawbone.

Main characteristics: It is the commonest dinosaur that could be found in the area of Cerro Cóndor. It was an herbivorous Sauropod belonging to the Cetiosauridae family. It had a very long neck that allowed it to reach the high trees to feed of their leaves. Almost all its skeleton was found, except the skull, but, according to what is known its form was perhaps of the Camasaurian kind or at least morphologically near it. Two adults and three young specimens were found, so, perhaps they were a family of gregarious habits, what would have allowed them to defend of the predators attacks.

Internet:
www.dinodata.net/Dd/Namelist/Tabp/P051.htm
dinosauricon.com/genera/patagosaurus.html
www.intelradio.com.ar/dinosaurios/patagosaurus.htm

Piatnitzkysaurus floresi

Studied by: José F. Bonaparte, 1979.
Length: 4.3 meters
Period: Middle Jurassic (160 million years)
Location: Cañadón Asfalto Formation, Chubut Province
Exhibition: Museo Argentino de Ciencias Naturales "Bernardino Rivadavia" (Argentinean Museum of Natural Sciences), Buenos Aires City.

Elements found:
1- Cervical vertebras ( 2 )
2- Dorsal vertebras ( 6 )
3- Scapular waist
4- Right humerus
5- Sacrum ,pelvis
6- Femur
7- Right tibia

Foto de José F Bonaparte	Foto de José F Bonaparte

Main characteristics: It was a carnivorous dinosaur of the Theropod group, member of the Allosauridae family. It was biped, it had strong and long back legs, as a contrast with the fore legs that were very small ones. Its head was very strong, of about 50 cm. It had conical, long teeth that suggest that it was a predator of small vertebrates. Its jawbone was very similar to the Allosaurus one. Its foreleg is unknown, but the morphology of the anterior extremity suggests that it was like the Allosaurus one. In this case, the hand has three fingers (digits I, II, III) and the digits IV and V are probably absent. In its back extremity the femur is more primitive than the Allosaurus one, in its head orientation. This little difference, probably caused not so little differences in their habits to walk and run.

Internet:
www.dinodata.net/Dd/Namelist/Tabp/P083.htm
dinosauricon.com/genera/piatnitzkysaurus.html
www.intelradio.com.ar/dinosaurios/piatnitzkysaurus.htm

Pisanosaurus mertii

Discovered by: Unknown in 1964
Studied by: Rodolfo Casamiquela in 1967 and José F. Bonaparte, Herbst, Scaglia and Vince in 1976.
Period: Middle Triassic (225 million years)
Length: 1 meter.
Weight: 3 to 5 Kg.
Location: Hoyada de las Lajas, 60 Km to the north of Ischigualasto (Valle de la Luna - Valley of the Moon), San Juan Province, in La Rioja Province.

Elements found: (1 specimen)
1- Right inferior jawbone (incomplete). It has 12 complete teeth and a jawbone with 15 complete teeth.
2- Right tibia of about 12 cm.
3- Cervical and dorsal vertebras.
4- Right fibula
5- Sacrum
6- Astragalus and heel
7- Left incomplete scapular, incomplete metacarpus
8- Incomplete femur.

Main characteristics: It is the oldest Ornithopod, Its teeth are strong and compact, suitable to eat the hard plants that there were along the semiarid areas where it lived. Its back extremities were thin and agile, what allowed it to run away from fast predators. The morphological studies of most of its body parts suggest that perhaps the early dichotomy that gave origin to both orders of dinosaurs: Saurischia and Ornithischia, could have happened before the late Triassic, perhaps, in the Middle Triassic.

Environment: Tropical climate, wet, with lakes and rivers, and coniferous forests. They lived side by side with crocodiles, Herrerasaurian, other Arcosaurus, etc. The most important plants were the dricoidium, ferns with seeds.

Internet:
www.dinodata.net/Dd/Namelist/Tabp/P089.htm
www.intelradio.com.ar/dinosaurios/pisanosaurus.htm

Secernosaurus koerneri

Discovered by: Unknown in 1923
Studied by: M. Brett -Surman, 1979
Period: Late Cretaceous (80 million years)
Length: 3 meters
Weight: 200 to 400 Kg.
Location: Valle del Río Chico, Santa Cruz Province.

Elements found:
1- Incomplete skull
2- scapular
3- Fibula
4- Ilium (2)
5- Caudal vertebras
6- Pubis

Main characteristics: It was thought that it was a primitive Hadrosaurus, due to its ilium, but nowadays it is supposed that this feature could have been produced by the fossil deformation. Speaking about the supposed Hadrosaurus in South America, the author thought that some group had lived here beforehand, still keeping, some primitive characteristics.

Internet:
dinosauricon.com/genera/secernosaurus.html
www.dinodata.net/Dd/Namelist/Tabs/S046.htm

Riojasaurus incertus

Discovered by: Unknown
Studied by: José F. Bonaparte in 1969
Period: Late Triassic (210 million years)
Length: 7 meters
Location: Upper layer of Los Colorados Formation, La Rioja Province and at the Quebrada del Barro Formation, San Juan Province.
Exhibition: Museo de la Universidad Nacional de Tucumán (Tucumán National University Museum) and at the Museo de Ciencias Naturales de la Universidad Nacional de La Rioja (Museum of Natural Sciences of La Rioja National University)

Elements found:
1- Cervical vertebras (4)
2- Dorsal vertebras (3)
3- Sacrum vertebras (3)
4- Scapular
5- Left coracoids
6- Left humerus
7- Left ulna and radio
8- Right hand
9- Left iliom
10- Left pubis
11- Left femur
12- Left isquion

Main characteristics: It is an herbivorous, representative of the primitive Prosauropod family, the Melanosauridae, It is the commonest kind registered in the upper layers of Los Colorados. It seems to be that the Riojasaurus Insertus is the most primitive member of the Prosauropods.

Internet:
www.dinodata.net/Dd/Namelist/Tabr/R030.htm
dinosauricon.com/genera/riojasaurus.html
www.intelradio.com.ar/dinosaurios/riojasaurus.htm

Saltasaurus loricatus

Discovered by: José F. Bonaparte, and J. E. Powel in 1980.
Studied by: Bonaparte and Powel
Period: Late Cretaceous (80 million years)
Length: 12 meters
Location: Estancia El Brete, on the southern area of Salta Province. They are levels corresponding to the pluvial deposits of the Lecho Formation.

Elements found:
1- Skull fragment
2- Cervical vertebras
3- Dorsal vertebras
4- Sacrum
5- Caudal vertebras
6- Breast bone plate
7- Right scapular
8- Left humerus
9- Right ilium
10- Right isquion
11- Right pubis
12- Right femur
13- Right tibia.
14- Dermic shelters (5 to 10 cm. diameter)

Main characteristics: This species is based into a group of five specimens that were found altogether, but disarticulated. The skeleton is represented almost as a whole, including some skull parts. The main features of its skeleton suggest that it was a heavy Sauropod, that perhaps lived in areas full of water. The most interesting features are two different kinds of ossifications, one of them is made of tiny bones of about 10 mm. diameter, placed one next to the other. The other one is made of bones like as shelters of about 10 cm. diameter, having a ventral fibrous surface, and an external one wrinkled with a central protuberance to the adherence of spikes or something like that. Saltasaurus Loricatus, seems to be the only one Sauropod having those bones characteristics like as dermic shelters. Perhaps it was a special adaptation to defend from predators.

Internet:
dinosauricon.com/genera/saltasaurus.html
www.dinodata.net/Dd/Namelist/Tabs/S005.htm
www.intelradio.com.ar/dinosaurios/saltasaurus.htm