Titanosaurids

Titanosaurids, or members of the relations Titanosauridae, are sauropod dinosaurs such as Saltasaurus and Titanosaurus. This family includes some of the heaviest creatures ever to walk the soil, such as the Argentinosaurus and the Paralititan — which might have weighed up to 100 tonnes (110 short tons), or perhaps even double that, if some poorly-described data is supposed (see the Bruhathkayosaurus).


Characteristics

Titanosaurs had small heads, even when compared to other sauropods. The head was also wide, alike to the heads of the Camarasaurus and the Brachiosaurus, but more stretched out. Their nostrils were large ("marcronarian"), and they all had crests shaped by these nasal bones. Their teeth were either somewhat spatulate (spoon-like), or like pegs or pencils, but were forever very small.

Their necks were comparatively short, for sauropods, and their tail was whip-like but not as long as a diplodocid. While the pelvis (hip area) was slimmer than some sauropods, the pectoral (chest area) was much wider, giving them an exclusively "wide-gauged" stance. As a result, the fossiled trackways of titanosaurs are definitely broader than than other sauropods. Their forelimbs were also stocky, but their rear limbs were longer. Their vertebrae (back bones) were solid (not hollowed-out), which may be a throwback to more primitive saurischians. Their spinal column was suppler, so they were probably more agile than their cousins, and better at education up.

From skin impressions establish with the fossils, it has been strong-minded that their skin was armored with a small mosaic of small, bead-like scales approximately a larger scale. One species has even been exposed with bony plates, like the Ankylosaurus.

While they were all huge, many were fairly standard in size compared to the other giant dinosaurs. There were even some island-dwelling dwarf species, almost certainly the result of allopatric speciation.

Nesting grounds

A large titanosaurid nesting earth was recently exposed in Auca Mahuevot, in Patagonia, Argentina, and another colony has allegedly been discovered in Spain. The small eggs, about 11–12 cm (4–5 in.) in diameter, restricted fissile embryos, complete with skin impressions (though there was no sign of feathers or dermal spines). Apparently more than a few hundred female saltosaurs dug holes, laid their eggs, and then buried them under dirt and vegetation. This gives proof of herd behavior, which the length of with their armor may have been a defense next to large predators like the Abelisaurus.

Range

The titanosaurs were the last great collection of sauropods before the Cretaceous-Tertiary death event, about 65–90 million years past, and were the dominant herbivores of their time. The other sauropods, like the diplodocids and the brachiosaurids, died out flanked by the late Jurassic and the mid-Cretaceous, while the titanosaurs appeared in the early Cretaceous, and grew in power until the end.

They were widespread, particularly in the southern continents that were then part of the supercontinent of Gondwana. Only Central and North America (then part of the Laurasia supercontinent), and Antarctica come into view to have never been occupied by titanosaurs.

Classification

For such a wipespread and winning group (they represent roughly a third of the total sauropod diversity known to date), the fossil evidence of titanosaurs is poor. Only recently have skulls or comparatively complete skeletons of any of the roughly 50 species of titanosaur been exposed. Many are poorly known, and much of the material may be deemed invalid or reclassified as sympathetic of the clade grows. The anchor taxon, the Titanosaurus, is chiefly poorly known.


Source from great site: http://www.rareresource.com

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