A revision of the fossil Erethizontidae of North America

Abstract

The North American fossil record of porcupines (Erethizontidae) is reviewed. Comparisons of cranial osteology, incisor enamel, auditory ossicles, and post-cranial elements of fossil samples with Recent Coendou and Erethizon samples indicate that all of the fossil porcupines in North America are congeneric with Erethizon. The following four species of Erethizon are recognized in the fossil record of North America: (1) E. bathygnathum appeared approximately 2.5 million years ago and lived in western North America during late Blancan and early Irvingtonian times. (2) E. cascoensis is recognized only in the early Irvingtonian El Casco local fauna of California. (3) A new species of Erethizon is known only from the early-middle Irvingtonian of Florida. (4) The extant E. dorsatum first appears in the United States during middle Irvingtonian times, later dispersing throughout most of temperal North America. Erethizon apparently differentiated from an ancestral form in South America prior to its appearance in North America during late Pliocene times. Even the earliest fossils already possessed the enlarged masticatory apparatus designed to consume the bark of temperate conifers. Other functional specializations in the skeleton of Coendou and Erethizon are considered.