Excellent Kettneraspis williamsi Oklahoma Trilobite

Description: Well-preserved example of a member of the Order Lichida, Family Odontopleuridae, with dramatically-displayed genal spines. While Kettneraspis is well known from the Haragan, far fewer examples come from the younger Bois’d’Arc, source of this one. Indeed, it is the only one Bob found last field season, and he chose to indicate the source in his label on the reverse. These may be a different species, and is some as Type A with the more common examples as Type B. Type A differs from B in having either 8 or 9 thoracic segments, a double row of tubercles on the lateral thoracic pleurae, a smaller occipital projection, and fewer to no tubercles on the border furrows of the librigenae.

Reference: Hansen, George P, Trilobites of Black Cat Mountain, 2009, pp 247-251