Lecture: Derived Titanosaurus

Overview

• Focus on the derived group of sauropods called Titanosaurus.
• Earlier groups discussed include macronarians, titanosaura forms, brachiosaurs.
• Derived titanosaurs include groups like Lithostrota and possibly "Colossal Soria."

Taxonomy and Characteristics

• Taxonomic classification for titanosaurs is debated.
• Known for several unique adaptations:
  • Loss of toes, distinguishing them from other neosauropods.
  • Wide-gauge trackways due to flared hips.
  • Unique tail vertebrae allowing a different range of motion.

Adaptations

• Hips & Trackways:

  • Flared hips for a broader stance and bigger gut.
  • Trackways in Texas show wide-gauge pattern.

• Tails:

  • Modified vertebrae with concave and convex surfaces for ball-joint movement.
  • Possible adaptation for momentarily bipedal stance.

• Armor and Osteoderms:

  • Development of bony scales (osteoderms) in the skin.
  • Common across all titanosaurs, suggesting an evolutionary role.

Notable Titanosaurs

• Lithostrota:

  • Includes smaller titanosaurs like Saltasaurus and Alamosaurus.
  • Alamosaurus prevalent in late Cretaceous North America.

• Colossal Soria or Longasoria:

  • Group includes some of the largest sauropods, e.g., Argentinosaurus and Patagotitan.
  • Patagotitan better documented with multiple finds in Argentina.
  • Challenges in defining this group due to lack of distinctive characteristics.

Evolutionary Insights

• Titanosaurs thrived in South America during the Cretaceous.
• Reintroduced into North America through land bridges in late Cretaceous.
• Size as a defensive mechanism against predators.
• Slow growth rate, taking 20-40 years to reach full size.

Current Understanding and Future Research

• Juvenile and adult sauropods had different diets and ecological roles.
• Nest discoveries like those of Saltasaurus provide insights into reproduction.
• Expect significant changes and discoveries in sauropod research in coming decades.