Newly Described Eunotosaurus africanus Material
The turtle has been in no rush to give up the secret of its shell — but after two centuries of close study, scientists are filling in the story of a structure unique in the history of life.
New research led by Tyler Lyson of Yale University and the Smithsonian Institution pushes back the origins of the turtle shell by about 40 million years, linking it to Eunotosaurus, a 260-million-year-old fossil reptile from South Africa. The work strengthens the fossil record and bolsters an existing theory about shell development while providing new details about its precise evolutionary pathway.
“Now we’ve got an intermediate shell, a transitional form that bridges the gap between turtles and other reptiles and helps explain how the turtle shell evolved,” said Lyson, a curatorial affiliate of the Yale Peabody Museum of Natural History and a Smithsonian postdoctoral researcher. “Eunotosaurus is an early offshoot of the lineage that gave rise to modern turtles — it’s an early stem turtle.”
Evolutionary Origin of the Turtle Shell. Lyson, Tyler R.; Bever, Gabe S.; Scheyer, Torsten M.; Hsiang, Allison Y.; Gauthier, Jacques A. Current biology : CB doi:10.1016/j.cub.2013.05.003
THE PENCIL SHARPENER ANOMALOCARID
505 mya - mid-Cambrian | everywhere
Hurdia was one of the largest organisms in the Cambrian oceans, reaching approximately 50 cm (1.5 feet) in length. Its head bore a pair of spiny claws which shoveled food into its pineapple-ring-like mouth.
A hollow, spike-shaped shell protruded from the front of its head.
This Early Miocene sunfish, Austromola angerhoferi, is estimated to have a total length of 3.2 meters (10’6”), making it the largest known Cenozoic teleost fossil. Mola mola can get somewhat larger — 3.33 m — although considering Austromola is know from only three specimens (the others being 1.5–1.7 and 2.4 m), I’d imagine it was considerably larger on average. Austromola is essentially “modern” in shape, although with some minor plesiomorphic traits (more vertebrae, hexagonal scales).
Gregorova, R. et al. (2009) A giant Early Miocene sunfish from the North Alpine Foreland Basin (Austria) and its implication for molid phylogeny. Journal of Vertebrate Paleontology 29(2) 359–371.
Finished this little guy earlier today. Not my favorite, but he’s okay. I need more practice with patience regarding these sorts of detailed critters. Mostly I think I just don’t like drawing animals with lots of segments… Hmmm…
8.5” x 11”
Cored pencil and digital.