Juvenile Phacopid Trilobite with Most Unusual Color Preservation

Description: This is a most unusual trilobite. Notice the pleasing café au lait color, and the regular darkened spots to the exoskeleton. These markings have been interpreted as the positions of internal muscle attachments . An alternative hypothesis is that the dark spots are actually preserved melanophores which could expand and contract , allowing the trilobite to change color as it moved about the seafloor surface much like the extant Plaice and Sole. Whatever the correct interpretation, these colors are of natural, rather than diagenic origin. There is also a genal spine from Bellacartwrightia and a tiny (2 mm) pyritized gastropod of the genus Paleozygopleura. The specimens were collected from a site on the border with Pennsylvania several decades ago, and to my knowledge specimens such as these have not been offered commercially until recently. The person who collected these in the field advises me that the current layer has been played out, so these will likely be the last until such time as extensive excavation is undertaken. For another example, see: Thomas E. Whiteley et al, Trilobites of New York, Plate 103.

Reference: Paleontology Vol. 11, Part 4, 1968 pp 498-9