Pattern Matching: Classification of Ammonitic Sutures Using Gis

Geographic Information Systems (GIS) is utilized to apply spatial analysis techniques to visually and quantitatively match ammonoid suture patterns for classification. The Turonian ammonite family Coilopoceratidae was chosen as the basis for this project, because the similar suture patterns within the family make species-level identification a challenge. A Coilopoceras springeri suture template was created by overlaying 10 different Coilopoceras springeri suture patterns, using the right holotype suture pattern as the basal or designation guide. Templates for Coilopoceras colleti and Hoplitoides sandovalensis sutures were constructed in the same manner. Sutures of known and unknown specimens were tested within the templates in order to identify species. The sutures of known specimens matched with the correct templates and did not compare well with other species’ templates. Sutures of unknown specimens clearly fit within one template better than within others and, hence, could be reliably classified to the species level. In addition to species classification, the GIS method provides a mechanism for both visual and quantitative comparisons of individual sutures. This GIS method will aid professional and avocational paleontologists, biostratigraphers, and geologists in classifying ammonite species, and may help further our understanding of suture morphogenesis and function by providing a standard basis for morphological comparison of complex sutural patterns. Department of Geosciences, Texas Tech University, Lubbock, Texas, 79409-1053, USA. [email protected]