Vulcanodontidae

Vulcanodontidae
Vulcanodon in a three-dimensional representation of life
Temporal occurrence
Lower Jurassic ( Hettangian to Toarcian )
201.3 to 174.1 million years
Locations
Africa
Systematics
Dinosaur (dinosauria) Lizard dinosaur (Saurischia) Sauropodomorpha Sauropods (Sauropoda) Vulcanodontidae
Scientific name
Vulcanodontidae
Cooper , 1984

Cladogram , simplified from Allain and Aquesbi (2008)
Sauropoda     Vulcanodontidae   Vulcanodon      Tazoudasaurus   Eusauropoda   Shunosaurus        Omeisaurus      Neosauropoda
Systematic position of Tazoudasaurus

The Vulcanodontidae is a family of primitive sauropod dinosaurs . It was originally set up by Cooper (1984) to summarize the early sauropods Vulcanodon and Barapasaurus . In the following years other genera were provisionally assigned to the Vulcanodontidae.

However, according to more recent analysis (Upchurch, 1995), the validity of the family has been questioned as Barapasaurus was much more closely related to later sauropods than to Vulcanodon . Barapasaurus has now been classified within the group of Eusauropods, a group that includes all sauropods except for very basal genera like Vulcanodon .

In 2004 the new, very primitive sauropod Tazoudasaurus was described, whereby clear similarities with Vulcanodon were found. To underpin these similarities, these researchers redefined the Vulcanodontidae as a sister group of the Eusauropods, which includes Vulcanodon and Tazoudasaurus . However, today's authors mostly do not follow this suggestion and thus continue to regard the Vulcanodontidae as invalid. In the following description the Vulcanodontidae refers to the group Vulcanodon - Tazoudasaurus .

Description and system

Both Vulcanodon and Tazoudasaurus are known for their relatively good skeleton finds: While Vulcanodon has a partial skeleton from Zimbabwe , Tazoudasaurus has two partial skeletons from the High Atlas of Morocco . Tazoudasaurus is also the only non-Eusauropod found so far from which good skull material is known. Although Vulcanodon was previously thought to originate from the Hettangian , new studies show that it actually originated from the Toarcian ; thus he is a contemporary of Tazoudasaurus .

Both genera are among the most primitive sauropods known and still show many characteristics that were otherwise only found in prosauropods . The well-preserved remains of the skull of Tazoudasaurus show a skull tapering towards the front, with the non-overlapping teeth running over the entire length of the lower jaw. Later sauropods had a rounded snout with overlapping teeth, which are usually only located in the front area of ​​the jaw. Although Tazoudasaurus and Vulcanodon are definitely quadruped (four-legged) animals, the metatarsals of Vulcanodon were very long compared to those of other sauropods (more than a third of the tibial length) and thus resembled those of prosauropods and theropods. Eusauropods had, as a further adaptation to a quadruped lifestyle, only short metatarsal bones (a quarter of the tibial length) that lay almost horizontally (semidigitigrade). Both Vulcanodon and Tazoudasaurus are characterized by some common primitive features (plesiomorphies) that are unknown in other sauropods; for example, the toe bones are longer than they are wide, and the lower end of the pubis ( pubic bone ) shows a sloping, apron-like structure.

Other genera traditionally assigned to the Vulcanodontidae

There are a number of other genera traditionally assigned to the Vulcanodontidae. Many of these genera are considered to be the noun dubium , so their validity is uncertain - among them are the Chinshakiangosaurus , known only through one jaw , the Kunmingosaurus, known for its partial skeleton, and the Zizhongosaurus, known for its three fragmentary bones . The position of these genera remains unclear.

The dwarf auropod Ohmdenosaurus found in Germany and known from leg bones is usually considered to be a valid genus, but its position outside the Eusauropod is only provisional. Kotasaurus from India was recently included in phylogenetic studies and is therefore considered a primitive sauropod outside of the Eusauropoda.

Web links

Commons : Vulcanodontidae  - Collection of images, videos and audio files

Individual evidence

1. ^ Gregory S. Paul: The Princeton Field Guide To Dinosaurs. Princeton University Press, Princeton NJ et al. 2010, ISBN 978-0-691-13720-9 , p. 172, online .
2. ^ Ronan Allain, Najat Aquesbi: Anatomy and phylogenetic relationships of Tazoudasaurus naimi (Dinosauria, Sauropoda) from the late Early Jurassic of Morocco. In: Geodiversitas. Vol. 30, No. 2, 2008, ISSN  1280-9659 , pp. 345-424, here p. 411: Fig. 46.
3. ↑ ^{a b c d e} Ronan Allain, Najat Aquesbi, Jean Dejax, Christian Meyer, Michel Monbaron, Christian Montenat, Philippe Richir, Mohammed Rochdy, Dale Russell , Philippe Taquet : A basal sauropod dinosaur from the Early Jurassic of Morocco. In: Comptes Rendus Palevol. Vol. 3, No. 3, 2004, ISSN  1631-0683 , pp. 199-208, doi : 10.1016 / j.crpv.2004.03.001 , digital version (PDF; 413.28 KB) .
4. ↑ Jeffrey A. Wilson: Integrating ichnofossil and body fossil records to estimate locomotor posture and spatiotemporal distribution of early sauropod dinosaurs: a stratocladistic approach. In: Paleobiology. Vol. 31, No. 3, 2005, ISSN  0094-8373 , pp. 400-423, doi : 10.1666 / 0094-8373 (2005) 031 [0400: IIABFR] 2.0.CO; 2 .
5. ↑ David B. Weishampel , Peter Dodson , Halszka Osmólska (eds.): The Dinosauria . 2nd edition. University of California Press, Berkeley CA et al. 2004, ISBN 0-520-24209-2 .