Meeting Abstract
84.3 Monday, Jan. 6 11:00 The impact of scale on ecomorphology: Using the feeding systems of bats and crocodilians as ontogenetic and macroevolutionary models GIGNAC, PM*; SANTANA, SE; Oklahoma State University, CHS ; University of Washington paul.gignac@okstate.edu
What links phenotypic stability and instability with morphological diversity? Comparative anatomists tend to approach this question from one of two perspectives. For key anatomical complexes such as the feeding apparatus, morphological changes during ontogeny are often interpreted in functional terms and linked to their putative importance for fitness. Across larger time scales, morphological transformations in these complexes are examined through character stability or mutability during cladogenesis. Because the fittest organisms must pass through ontogenetic changes in size and shape, it is predicted that addressing such transformations on different time scales would illuminate the factors generating phenotypic diversity. However, this is partly based on the assumption that adult form, in particular, tightly fits the adult niche. To assess the import of this assumption, we contrasted two systems for which ontogenetic and macroevolutionary changes in the feeding apparatus have been strongly implicated in ecological function and lineage diversification, Chiroptera and Crocodylia. Chiropterans reach their adult feeding niche at a comparable body size to when they attain somatic maturity. Crocodylians, on the other hand, reach their adult feeding niche far below their potential maximum size. Here we interpret developmental and evolutionary changes in bite-force capacity and cranial musculoskeletal anatomy within established frameworks of whole-animal performance and evolutionarily stable configurations; we offer insights into how body-size dependent phenotypes and their performance capacities may obscure our ability to identify mechanisms of morphological diversification, and we chart future directions to avoid such pitfalls in biomechanics research.
