Laurasia formed - the Atlantic Ocean, though Greenland (attached to North America) and Europe were still joined together. The separation of Europe and Greenland occurred around 55 million years ago (at the end of the Paleocene). Laurasia finally divided into the continents after which it is named: Laurentia (now North America) and Eurasia (excluding the Indian subcontinent). Laurasia Laurasia () was the more northern of two supercontinents (the other being Gondwana) that formed part of the Pangaea supercontinent around (Mya). It separated from Gondwana (beginning in the late Triassic period) during the breakup of Pangaea, drifting farther north after the split.
Unenlagiinae allopatric speciation. Unenlagiinae Unenlagiinae is a subfamily of dromaeosaurid theropods. Unenlagiines are known from South America and Antarctica. Most unenlagiines have been discovered in Argentina. The largest was "Austroraptor", which measured up to 5–6 m (16.4–19.7 ft) in length, making it also one of the largest dromaeosaurids. The subfamily is distinguished from other dromaeosaurids by a tail stiffened by lengthy chevrons and superior processes, sharp articulate claws, and a posteriorly oriented pubis. Their distinct anatomy from Laurasian dromaeosaurids was likely a consequence of the breakup of Pangaea into Gondwana and Laurasia, where the geological isolation of unenlagiines from their relatives