"The neurocranium of the shark Xenacanthus (sensu lato) from the early Permian of Texas shares derived characters with the neurocrania of various other Paleozoic shark genera, including Tamiobatis, 'Cladodus,' 'Ctenacanthus,' ...

"The South American chaco is centrally situated on the border of the tropics and is xeric-adapted woodland with some open areas, wet places, and savanna. Driest in the center and wettest in the eastern pantanal savanna, ...