Ancient Tusked Sea Cow Unearthed in Panama
The remarkably complete fossil skeleton of a sea cow with large incisor tusks that lived approximately 20 million years ago (Miocene Epoch) has been discovered in Panama.
The newly-discovered sea cow, named Culebratherium alemani, is a tusked seagrass-grazing relative of modern dugongs.
“While only one species of dugong is alive today — a second, Steller’s sea cow, was hunted to extinction within 27 years of its discovery — about 30 species have been recovered in the fossil record,” said Dr. Jorge Velez-Juarbe, a paleontologist in the Department of Mammalogy at the Natural History Museum of Los Angeles County and the Department of Paleobiology at the National Museum of Natural History, Smithsonian Institution.
“The group originated in the West Atlantic and Caribbean and dispersed westward through Panama, whose seaway did not close until a few million years ago, and south to Brazil.”
The fossil skull, vertebrae, ribs and other bones of Culebratherium alemani were recovered from marine deposits of the Culebra Cut of the Panama Canal.
“About 15 feet (4.6 m) long, this individual was not done growing,” Dr. Velez-Juarbe said.
“Its tusks had only begun to protrude and its newest molars showed little wear, indicating it was not yet an adult. But it was a powerful eater.”
Dr. Velez-Juarbe and his colleague, Dr. Aaron Wood from Iowa State University and the Florida Museum of Natural History, propose that Culebratherium alemani’s thick neck muscles, tusks and downward-pointing snout were adaptations for digging pits in the ocean floor to get to the underground stems of seagrass, the plants’ most nutritional parts.
“Finding Culebratherium alemani is pretty good evidence that there was seagrass in this region 20 million years ago,” Dr. Velez-Juarbe said.
“This particular group of sirenians are seagrass specialists.”
The discovery is described in a paper in the Journal of Vertebrate Paleontology.
Jorge Velez-Juarbe & Aaron R. Wood. An early Miocene dugongine (Sirenia: Dugongidae) from Panama. Journal of Vertebrate Paleontology, published online February 15, 2019; doi: 10.1080/02724634.2018.1511799