Clovis gomphotheres

Guadalupe Sanchez and colleagues reported earlier this month that Clovis artifacts have been found in association with parts of two gomphothere skeletons in Mexico: “Human (Clovis)–gomphothere (Cuvieronius sp.) association ∼13,390 calibrated yBP in Sonora, Mexico”.

Gomphotheres are an extinct family of proboscideans, previously thought to have disappeared long before the first occurrence of humans in the Americas. In fact the last occurrence of Cuvieronius before this is more than 40,000 years ago. It’s a good example of the last occurrence fallacy – the assumption that if attested dates of two things don’t overlap, they cannot have co-occurred. In reality, of course, the last known occurrence must be earlier than the true last occurrence of a species. How much earlier is a matter of sampling density, and paleontological sampling is usually pretty sparse – especially for rare species.