"Tiktaalik" lived approximately 375 million years ago. Paleontologists suggest that it is representative of the transition between non-tetrapod vertebrates such as "Panderichthys", known from fossils 380 million years old, and early tetrapods such as "Acanthostega" and "Ichthyostega", known from fossils about 365 million years old. Its mixture of primitive fish and derived tetrapod characteristics led one of its discoverers, Neil Shubin, to characterize "Tiktaalik" as a "fishapod." Unlike many previous, more fish-like transitional fossils, the "fins" of "Tiktaalik" have basic wrist bones and simple rays reminiscent of fingers. They may have been weight-bearing. Like all modern tetrapods, it had rib bones, a mobile neck with a separate pectoral girdle, and lungs, though it had the gills, scales, and fins of a fish. However in a 2008 paper by Boisvert at al. it is noted that "Panderichthys", due to its more derived distal portion, might be closer to tetrapods than "Tiktaalik", which might have independently developed similarities to tetrapods by convergent evolution.