North-Central Section - 39th Annual Meeting (May 19–20, 2005)

Paper No. 8
Presentation Time: 8:00 AM-12:00 PM


CRAWFORD, Robert S., Department of Geology, Kent State Univ, Kent, OH 44242,

Re-examination of material from the Yale Peabody Museum collected by K. M. Waage and others from the Fox Hills Formation (Maastrichtian) of South Dakota has yielded new specimens of Latheticocarcinus shapiroi Bishop, 1986, (Homolidae de Hann, 1839) including previously unknown extra-lineal portions of the carapace. Digital photographs used in conjunction with Adobe Photoshop and traditional ink drawing methods provided an efficient and accurate means by which to reconstruct the carapace of L. shapiroi from disarticulated partial remains. Due to the presence of the linea homolicae (a lineation separating the lateral and medial potions of the dorsal carapace that functions to allow the carapace to split during molting), the dorsal carapace of members of the family Homolidae rapidly disarticulate.  As a result, very few fossil homolid specimens possessing the extra-lineal portions of the carapace are known.  This lack of extra-lineal flanks has led to the misassignment of many fossil homolids to other families. The discovery of the extra-lineal flanks has confirmed the correct placement of L. shapiroi within the Homolidae. Traditional ink drawing methods of rendering fossil specimens from incomplete material can result in inaccurate interpretations of carapace morphology.  By using digital photographs, substitution of missing portions of the dorsal carapace and extra-lineal flanks can be made in a time-efficient manner. Photoshop provides a method by which the extra-lineal and medial dorsal carapace segments can be accurately incorporated into a restoration of the dorsal carapace. The resulting composite image can then be hand traced and later scanned. Final corrections and labeling can then be easily and efficiently made within Photoshop, resulting in a publication-ready image. The combination of traditional ink drawing and digital illustration methods provides an efficient and accurate method for producing drawings, and although the composite image cannot account for subtle variation between individuals, it does allow for an accurate reconstruction of an organism from incomplete material.