Morphological analysis: A powerful tool in wildlife forensic biology

Pepper W. Trail
2021 Forensic Science International: Animals and Environments  
Please cite this article as: { doi: This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. ABSTRACT: It is a truism that "structure is the first thing that we notice whenever looking at organisms" (Gans 1985) , and the description and analysis of structure is the province of the science of morphology. Morphological
more » ... lysis is a well-established and cost-effective technique for the taxonomic identification of wildlife remains. Despite this, it is under-utilized in wildlife crime investigations for reasons including a shortage of trained specialists, the challenge of accessing reference specimens, and the perceived greater rigor of DNA analysis. This paper reviews the methodology of morphological analysis, addresses perceived challenges, and demonstrates the effectiveness of the technique in wildlife forensic biology casework at the National Fish and Wildlife Forensic Laboratory of the U.S. Fish and Wildlife Service. Identification of the species present in wildlife evidence is typically made either by morphological or DNA analysis. In morphological analysis, trained and competency-tested J o u r n a l P r e -p r o o f Rev -2 specialists make species identifications based on physical characters present in the evidence, such as avian plumage patterns, mammal dentition, or reptile scale counts. Evidence items are compared to verified reference specimens and/or authoritative data sources, and taxonomically informative characters are documented (for an excellent review of this process in the zooarchaeological context, see Lyman 2019). This process of morphological comparison is formalized in field guides, technical keys, and taxonomic monographs, and is routinely used for species identification in a wide variety of disciplines, including paleozoology, botany, entomology, ichthyology, herpetology, ornithology, and mammalogy. Indeed, morphological characters formed the exclusive basis for species definitions from the time of Linnaeus until recent decades. The detailed morphological "diagnosis" remains a required and essential element for new species descriptions, even as behavioral, ecological, and genetic characters are now often included (for a recent example, see Sornoza-Molina et al. 2018) . Identifications of wildlife evidence by morphological examination are routinely admitted as evidence in US courts, demonstrating the acceptance of the method by the legal system. Morphological analysis in biology proceeds through the hierarchy of taxonomy, from order to family to genus to species, with shared derived characters (synapomorphies) noted at each taxonomic level. For example, a whole trophy mount of a polar bear (Ursus maritimus) can be identified to order Carnivora based on its carnassial teeth and robust claws, to the family Ursidae J o u r n a l P r e -p r o o f J o u r n a l P r e -p r o o f
doi:10.1016/j.fsiae.2021.100025 fatcat:37qpqdyus5gbzj2j5aqknaevo4