Complex sentence: Ralph E. Molnar is a paleontologist who has been Curator of Mammals at the Queensland Museum and more recently of the Museum of Northern Arizona and a research associate at the Texas natural Science Centre.
Split into simpler sentences: Ralph E. Molnar is a paleontologist who had been Curator of Mammals at the Queensland Museum and more recently associated with the Museum of Northern Arizona. He is also a research associate at the Texas natural Science Centre.