The newly-described species, Ardetosaurus viator, roamed the Earth during the Late Jurassic epoch, approximately 150 million years ago. This dinosaur was a type of diplodocid, a family of large sauropod dinosaurs known for some of the longest creatures to have ever walked the planet.
Characteristics of Sauropods
According to Tom van der Linden of the Oertijdmuseum and his colleagues, sauropods are well-studied and are recognized as the largest terrestrial vertebrates throughout much of the Mesozoic era. Their defining features include:
- Long necks and tails
- Extreme size
- A complex bird-like air sac system that aided respiration
- Unique feeding and digestive strategies
- Oviparous reproduction, where they laid eggs
Sauropod fossils have been discovered on every continent, including Antarctica, making them a widely distributed group.
Diplodocidae Family Overview
The Diplodocidae family, established in 1884, is one of the most recognizable sauropod families. Diplodocids are defined by their closer evolutionary relationship to Diplodocus than to Dicraeosaurus. Key features of these dinosaurs include:
- Extremely long necks
- Even longer tails
Diplodocid paleontology is a thriving field, with studies contributing to our understanding of their:
- Morphology (form and structure)
- Histology (study of tissues)
- Biomechanics (movement and mechanics)
- Pathologies (diseases)
- Ecology (relationship with the environment)
Temporal and Geographic Range
Diplodocids have been found in North America, South America, Europe, and Africa. Their temporal range spans from the Oxfordian to possibly the early Valanginian period (161 to 135 million years ago). They were especially abundant during the Kimmeridgian and Tithonian stages of the Upper Jurassic, primarily in the Morrison Formation of the western United States.
Discovery of Ardetosaurus viator
The remains of Ardetosaurus viator were excavated in 1993 from the Howe-Stephens Quarry in the Morrison Formation. This dinosaur represents the first skeletally mature sauropod specimen described from this site. The study of this specimen revealed important insights into the variability of morphological features in diplodocine sauropods, such as:
- Laminar capture in the cervico-dorsal transition
- Laminar transitions in caudal vertebrae
Additionally, the specimen preserved a rare first chevron (a bone found beneath the tail) with a unique structure. Comparisons with other sauropods and non-avian dinosaurs suggest this could offer clues to understanding sexual dimorphism (differences between males and females) in sauropods through micromorphological characteristics in chevrons.
Multiple-Choice Questions (MCQs):
- When did Ardetosaurus viator live?
a) 200 million years ago
b) 150 million years ago
c) 100 million years ago
d) 50 million years ago
Answer: b) 150 million years ago - What family does Ardetosaurus viator belong to?
a) Theropoda
b) Diplodocidae
c) Tyrannosauridae
d) Ceratopsidae
Answer: b) Diplodocidae - Which of the following is NOT a characteristic of sauropods?
a) Long necks and tails
b) Large size
c) Oviparous reproduction
d) Sharp teeth for hunting
Answer: d) Sharp teeth for hunting - Which continent has NOT produced sauropod fossils?
a) Europe
b) Antarctica
c) North America
d) Australia
Answer: d) Australia - What does the discovery of the first chevron in Ardetosaurus viator suggest?
a) New feeding strategies
b) Evidence of sexual dimorphism
c) Faster locomotion
d) Increased predation
Answer: b) Evidence of sexual dimorphism