Lourinhanosaurus
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| Lourinhanosaurus Fossil range: Late Jurassic |
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| Lourinhanosaurus antunesi Mateus, 1998 |
Lourinhanosaurus (meaning "Lourinhã [Formation] lizard") was a carnivorous theropod dinosaur genus that lived during the Late Jurassic Period (Kimmeridgian/Tithonian). Its first remains were found at Peralta, near Lourinhã, Portugal in 1982, but were not described until 1998, by Portuguese paleontologist Octávio Mateus.
Its type (and to date only) species is L. antunesi, in honour of Portuguese paleontologist Miguel Telles Antunes.
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[edit] Material
To date, the most complete specimen of L. antunesi found is a partial skeleton. The holotype, ML 370, consists of the remains of six cervical vertebrae with six ribs, five sacral vertebrae with ribs, 14 caudal vertebrae, eight chevrons, both femora, right tibia and fibula, one metatarsus, two ilia and both pubes and ischia, as well as an associated 32 gastroliths.
A femur (ML 555) found at Porto das Barcas has also been referred to L. antunesi.
Besides these specimens, around 100 eggs (specimen number ML 565), some of them containing embryonic bones, have been found in 1993 at the nearby beach of Paimogo. These were soon assigned to L. antunesi.
Both the skeleton and the eggs are on display at Museu da Lourinhã.
[edit] Systematics
Lourinhanosaurus antunesi's relationships have been uncertain, and no firm consensus has been reached as to its relationships. Initially regarded as a primitive member of Allosauroidea, it was later discussed as being closely related to Sinraptoridae, a more inclusive clade within Allosauroidea. Recently, some researchers have been favourable to the idea that L. antunesi is not even an allosauroid, but in fact a member of Megalosauroidea, a more primitive group of tetanuran theropods.
[edit] Paleobiology
L. antunesi was a rather large carnivorous dinosaur. The specimen found was a sub-adult, measuring some 4.5 m in length and weighting around 160 kg. A full grown adult would have reached 8 meters, taking 10 years to reach that size.
Interestingly, in the nest found at Paimogo, were also found eggs with embryos of crocodiles. It's possible that these crocodiles parasitized L. antunesi's nests in the same way cuckoos today do with other birds.
Though gastroliths have been found in other theropods since the description of L. antunesi, this was the first theropod dinosaur for which this kind of remains have been assigned. It was concluded during the description that these stones belonged to the animal, and were not swallowed while eating an herbivorous dinosaur.
[edit] References
- Antunes, M.T. & Mateus, O. (2003). Dinosaurs of Portugal. C. R. Palevol 2: 77-95.
- Mateus, O. (1998). Lourinhanosaurus antunesi, a new Upper Jurassic allosauroid (Dinosauria: Theropoda) from Lourinhã (Portugal). Memórias da Academia de Ciências de Lisboa 37: 111-124.
