Earliest Eutherian Ear Region: A Petrosal Referred to Prokennalestes from the Early Cretaceous of Mongolia

摘要: Abstract A right petrosal from the ?Aptian or Albian Khoobur locality is referred on basis of size and morphology to Prokennalestes trofimovi, earliest eutherian previously known only dentigerous elements. The shows a mosaic primitive derived features, bearing purported therian morphotypes. Among features shared with Early Cretaceous prototribosphenidan Vincelestes other more basal taxa that are modified in later eutherians metatherians pattern basicranial arterial venous circulation, including prootic canal an intrapetrosal inferior sinus; vertical paroccipital process; fenestra semilunaris, incomplete wall between cavum epiptericum supracochleare. therians cochlea coiled through minimum 360°, extending range oldest occurrence such by at least 10 million years. Shared Late...