The Brachytrachelopan was a sauropod dinosaur that lived in the latter ages of the Jurassic period. Based on the age of the fossils, it is estimated that the Brachytrachelopan existed about 155 to 150 million years ago. This time period covered the end of the Kimmeridgian age and the beginning of the Tithonian age.
The Brachytrachelopan belonged to the family Dicraeosauridae. The species of this family had smaller neck sizes as compared to other Jurassic sauropods. The neck of the Brachytrachelopan was amongst the shortest of the group. This distinguished it very clearly in the family and its name mirrors this fact.
The length of the Brachytrachelopan was about 9 to 11 meters. Its weight was presumed to be 5 to 10 tons. It was indeed a large dinosaur but was much smaller as compared to other sauropods, some of which attained an adult weight of 40 tons.
The remains of the Brachytrachelopan were discovered in Argentina. It is theorized that the shorter neck of the organism was an adaptation for the South American environment. The Brachytrachelopan was an herbivore and it is believed that vegetation in its environment was low lying.
The translation of the name ‘Brachytrachelopan’ is threefold. The prefix ‘brachy’ is used to denote ‘short’. It has Greek origins and is seen very commonly in scientific names such as ‘brachycephalic’, ‘brachydactyly’, etc. The word ‘trachelos’ translates to neck in English. ‘Pan’ is the Greek god of wild mountains, shepherds and flocks.
Thus Brachytrachelopan roughly translated to ‘a small-necked Pan’.
The remains of the Brachytrachelopan were discovered by an Argentinian shepherd. The species name Brachytrachelopan mesai honors that shepherd, Daniel Mesa.
The christening of the dinosaur was done by paleontologist Oliver Rauhut in 2005.
Discovery of fossils
The remains of the Brachytrachelopan were discovered in Canadon Calcero Formation in Chubut, Argentina. They were found by Daniel Mesa, a local sheep farmer who was out to retrieve his flock back from their grazing time.
They were first examined by scientists Rauhut, Fechner and associates.
Nature of fossils
- The skull was noticeably missing from amongst the remains. This had made determining length and feeding habits a bit of a challenge. But estimates were made based on comparisons with other dicraeosaurids.
- The vertebral column was well represented in the fossils. Eight cervical and twelve dorsal vertebrae were found.
- The sacrum, composed of three vertebrae, was also discovered.
- A few incomplete rib specimens were seen as well.
- The pelvic girdle was represented by a single iliac bone.
- The hind leg bones were amongst the better preserved samples, with parts of the left femur and tibia being found.
The cervical vertebrae of the Brachytrachelopan were almost half the size of those of diplodocids. Thus, the neck of the Brachytrachelopan was significantly shorter than its cousins like the Barosaurus and the Diplodocus.
The Brachytrachelopan is classified under sub order Sauropodomorpha and family Dicraeosauridae.
Dicraeosaurids had typical reduced necks and were found in South America and Africa, indicating they were present all throughout Gondwana (the super continent composed of South America and Africa in the Jurassic period).
As other Dicraeosaurids were discovered and defined much before the discovery of the Brachytrachelopan, its classification was made much easier. There was very little doubt about its location in the taxonomic tree.
Current location of fossils
The bones of the Brachytrachelopan are presently conserved at the Museum of Paleontology Egidio Feruglio in Trelew, Argentina.
The Canadon Calcero Formation
- The Canadon Calcero Formation is a part of the Monte Fitz Roy Mountains in the Chubut region of Patagonia.
- It is composed of hilly regions which are of average height, but are very treacherous for mountain climbers.
- The Canadon Calcero formation is not the conventional sedimentary rock structure where dinosaur fossils are usually seen. Hence scientists had not thought to explore this area for fossils. Other Argentinian sites such as the Ischigualasto Formation have interested paleontologists much more, and rightly so as many vertebrate fossils were found there.
- The Brachytrachelopan remains were exposed only after the rocks overlying them were eroded with time.
Rauhut completed his under graduation from the University of Berlin. He then went on to complete his graduation and doctorate from the University of Bristol.
His area of interest is the progression of dinosaurs in the Jurassic and Cretaceous periods of the Mesozoic era.
Rauhut has published several studies in collaboration with scientists like Paul Sereno and Hungerbuhler.
He currently works in Munich.
- The Brachytrachelopan was moderate sized dinosaur as compared to its contemporaries. Its length was about 30 to 35 feet from snout to tail. Some scientists estimate it could have weighed as much as 10,000 kilos. These dimensions were much lesser than those of the Dicraeosaurus.
- The height of the Brachytrachelopan is difficult to determine as no skull bone found. But the flexibility of the cervical vertebrae dictates that it could not have raised its neck above 2 to 3 meters.
- The neck of the Brachytrachelopan was visibly short.
- Its extremities were stout and pillar like.
- The Brachytrachelopan had a long tail, but it was not as long as the diplodocids.
Habits and habitat
- Despite the absence of jaw bones, it can be determined that the Brachytrachelopan was an herbivorous dinosaur.
- It walked on all four legs with its head very close to the ground.
- The Brachytrachelopan was most likely present all throughout Gondwana. The iguantodontians were noticeably absent in Gondwana and dicraeosaurids were likewise absent in other continents. This may indicate that dinosaurs which adapted to feeding on low lying vegetation developed to dicraesaurids in Gondwana and to iguantodontians elsewhere in the world.
- Very little is known about the environment of the Brachytrachelopan except that it chiefly had smaller sized trees and plants.
Related and coexisting species
It possibly shared its habitat with many Jurassic vertebrates. As no other dinosaur remains have been excavated alongside those of the Brachytrachelopan, this is merely a conjecture.
The Brachytrachelopan was amongst the larger dinosaurs of South America. Its discovery has shown that there may be many dicraeosaurid dinosaurs in South America and Africa that have not yet been discovered due fossils being in unorthodox locations.