Ghost Ranch and Coelophysis

In the 1940s, American Museum of Natural History crews cut blocks of rock out of the Whitaker Quarry here and shipped them to New York. Some were never opened. Sixty years later a researcher split one and found an entirely new animal inside, which is how Effigia okeeffeae came to be described in 2006.

It is a good name. Effigia is Latin for ghost, for the ranch, and the species honours Georgia O'Keeffe, who painted these badlands for years and took an interest in the quarry when it was found. The animal itself is stranger than the story. It is not a dinosaur but a suchian, on the crocodile side of the family tree, and yet it had an edentulous beaked skull, an enlarged eye socket and a body plan that looks remarkably like an ostrich-mimic dinosaur. It is one of the clearest cases of convergent evolution in the Triassic.

Effigia also rewrote what the quarry was. For decades the Ghost Ranch bone bed was understood as a nearly monospecific death assemblage of the early theropod Coelophysis, the reading Edwin Colbert set out in 1989, and the numbers are extraordinary on their own: something close to a thousand individuals are estimated to be preserved there. Since then many other kinds of reptile have been reported from the same rock, and the picture has filled out into a crowded Triassic community.

The ranch around it is 21,000 acres in Rio Arriba County, about 65 miles northwest of Santa Fe and 14 miles from Abiquiu. It sits inside Piedra Lumbre, or Shining Rock, a land grant made in 1766 by Charles III of Spain, and it was designated a National Natural Landmark in 1976. It is owned by the Presbyterian Church and run as a retreat and education centre, and it was O'Keeffe's summer home and studio. The name comes from an older and darker story, a pair of cattle-rustling brothers in the 1880s whose guests had a way of not leaving.