COPROLITES FILL THE NEUROCRANIUM OF A MIOCENE PERCIFORM FISH FROM MARYLAND

Coprolites (fossilized feces) come in a great variety of shapes and sizes. They can also preserve a wide range of biogenic inclusions, ranging from DNA fragments, bacteria, spores, phytoliths, wood fragments to a variety of vertebrate tissues and tooth impressions. We report on the first occurrence of coprolites preserved within the neurocranium of a fossil organism. CMM-V-2022 preserves most of the neurocranium of a new species of perciform fish (an electric star-gazer, Uranoscopidae, Teleostei). The fossil, of Miocene age, derives from the southern end of Calvert Cliffs, Calvert County, Maryland, U.S.A (Little Cove Point Member, St. Marys Formation, Chesapeake Group). The feces present as tiny oblong spheroid pellets, measuring 2–3mm in length along their long axis and 0.75–1.25mm in diameter through the central orthogonal axis. The fecal pellets in this fish skull are presumed to have originated from the scavenging activities of an as yet unknown invertebrate. Two other sedimentary samples from the Little Cove Point Member preserve typologically identical fecal pellets in a dense cluster and sinuous fecal-pellet trails, interpreted as evidence that this was a burrowing organism. The burrows measure approximately 3mm in diameter and are presumed to have been produced and back-filled with fecal pellets by the originating organism.