They were some of the heaviest creatures ever to walk the earth. Titanosaurs included "Saltasaurus", "Isisaurus", "Argentinosaurus" and "Paralititan". The group includes the largest land animals known to have existed, such as "Patagotitan" estimated at long with a weight of and the comparably sized "Argentinosaurus" and "Puertasaurus" from the same region. They were named after the mythological Titans of Ancient Greece.
The titanosaurs were the last great group of sauropods before the Cretaceous–Paleogene extinction event. They were the dominant herbivores of their time. The fossil evidence suggests they replaced the other sauropods, like the diplodocids and the brachiosaurids, which died out between the Upper Jurassic and the mid-Cretaceous.
Broadly, their skeleton was similar to earlier sauropods, but with a few key differences. The pelvis (hip area) was slimmer than some sauropods, but the pectoral (chest area) was much wider. This them a uniquely 'wide-gauged' stance: their front legs were wider apart, and usually longer than their hind legs. This can be seen very clearly in the "Argentinosaurus". As a result, the fossilised trackways of titanosaurs are broader than other sauropods. Their vertebrae (back bones) were solid (not hollowed-out). Their spinal column was more flexible, so they were probably more agile than their cousins and better at rearing up.
The group was quite varied. Some of the smaller types did not have longer forelimbs ("Epachthosaurus"), and one Chinese find ("Xinghesaurus") had an extremely long neck. These differences must reflect adaptations to differences in their habitats and life-style, but at present there is little known about this. Many of these discoveries are quite recent.
Titanosaurs were widespread. Their fossils have been found in all continents, even Antarctica. Four well preserved skeletons of a titanosaur species were found in Italy.
They were especially numerous in the southern continents (then part of the supercontinent of Gondwana). Australia had titanosaurs around 96 million years ago: fossils have been discovered in Queensland of a creature around 25 meters long (82 feet). Remains have also been discovered in New Zealand.
Titanosaurs hold the world record for the size of a land animal. One place in the Argentine had 150 bones from seven titanosaurs. The largest were from an animal 40 metres (~130 feet) long and 20 metres (35 feet) tall. It would have weighed about 77 tonnes. A local farm worker stumbled on the remains in the desert near La Flecha, about 250km (135 miles) west of Trelew, Patagonia. The BBC flew a team out to record the event.
As a group, titanosaurs were high browsers, eating leaves and branches from tall trees. This is in contrast to other herbivores like the Ceratopsia and Ankylosauria, which were low browsers, eating lower vegetation like shrubs. As a general rule, high browsers can eat lower-growing plants, but low browsers cannot eat from tall trees. Like the earlier sauropods (e.g. "Diplodocus") titanosaurs had peg-like teeth and no grinders. This means they used gastroliths to grind their food, and had a huge vat-like stomach where bacteria decomposed it.
Fossilized dung found with late Cretaceous titanosaurids suggests a broad, unselective plant diet. Besides the plant remains that might have been expected, such as cycads and conifers, there were an unexpectedly wide range of monocotyledons, including palms and grasses (Poaceae), including ancestors of rice and bamboo. This has given rise to speculation that herbivorous dinosaurs and grasses co-evolved.
A large titanosaurid nesting ground was discovered in Auca Mahuevo, in Patagonia, Argentina and another colony has reportedly been discovered in Spain. Several hundred female saltasaurs dug holes with their back feet, laid eggs in clutches averaging around 25 eggs each, and buried the nests under dirt and vegetation. The small eggs, about 11–12 cm (4–5 in) in diameter, contained fossilised embryos, complete with skin impressions. The impressions showed that titanosaurs were covered in a mosaic armour of small bead-like scales. The huge number of individuals suggests herd behavior which, with their armour, could have helped give protection against large contemporary predators such as "Abelisaurus".
Crosshair
A crosshair is a circular range most commonly associated with telescopic sights for aiming firearms; often used in first-person shooter video games. It lets the player know what and where they are going to shoot.
Chemical similarity
Chemical similarity or molecular similarity is a similarity between two different molecules. Two molecules with chemical similarity may do the same or a very similar thing in an organism. They might also have very similar chemical structures. It can be used to predict the properties of certain chemicals.
Battle of Thermopylae
The Battle of Thermopylae, 480 , was a battle in the second Persian invasion of Greece. It was fought between an alliance of Greek city-states, led by Sparta, and the Persian Empire of Xerxes I. It took place at the pass of Thermopylae. The battle was fought for over three days, at the same time as the naval Battle of Artemisium.
The Persian invasion was a delayed response to the defeat of the first Persian invasion of Greece. In 500 BC the lonians settled in the western coast of Asia minor and rose up against Persian’s King Darius. After six years, the rebellion was ended. In 490 BC the Persians sailed to punish the Athens. Darius fought against Athens and promised to punish them because they went to Persian land to help The Ionians. This First Persian War was ended by the Athenian victory at the Battle of Marathon.
Xerxes had a huge army and navy, and in this Second Persian War set out to conquer all of Greece.
The Athenian general Themistocles suggested the Greek allies should block the Persian army at the pass of Thermopylae, and block the Persian navy at the Straits of Artemisium.
A Greek force of about 7,000 men marched north to block the pass in the summer of 480 BC. The huge Persian army arrived at the pass in late August or early September.
Heavily outnumbered, the Greeks held off the Persians for seven days in total (including three of battle), before the rearguard was annihilated in one of history's most famous last stands.
During two full days of battle, the small force led by King Leonidas I of Sparta blocked the only road by which the massive Persian army could pass. After the second day of battle, a local resident named Ephialtes betrayed the Greeks by revealing a small path that led behind the Greek lines. Aware that his force was being outflanked, Leonidas dismissed the bulk of the Greek army, and remained to guard the rear with 300 Spartans, 700 Thespians (who refused to leave), 400 Thebans and perhaps a few hundred others. Most of them were killed.
The pass at Thermopylae was thus opened to the Persian army according to Herodotus, at the cost to the Persians of up to 20,000 fatalities. The Greek rearguard meanwhile, was annihilated, with a probable loss of 2,000 men, including those killed on the first two days of battle.
After this engagement, the Greek navy at Artemisium received news of the defeat at Thermopylae. Since their strategy required both Thermopylae and Artemisium to be held, and given their losses, the Greek navy decided to withdraw to Salamis. The Persians then captured the evacuated Athens. During the battle the Greek navy lured the Persians into a narrow pass and obliterated at least 200 Persian war ships, thanks to Themistocles.
Seeking a decisive victory over the Allied fleet, the Persian fleet attacked, but were defeated at the Battle of Salamis in late 480 BC. Fearing to be trapped in Europe, Xerxes withdrew with much of his army to Asia, leaving Mardonius to complete the conquest of Greece. The following year, however, saw a Greek army decisively defeat the Persians at the Battle of Plataea, thereby ending the Persian invasion.