Meeting Abstract

P2.83  Thursday, Jan. 5  Skeletal Development of Hyla chrysoscelis and the Skeletal Evolution of NA Hylids DAGLEY, Brian*; MAGLIA, Anne; SHEARMAN, Rebecca; Framingham State University; National Science Foundation; Framingham State University rshearman@framingham.edu

Ossification sequence reflects developmental progress and may help elucidate associations between changes in timing of developmental events and adult morphology. North American (NA) hylids are a morphologically diverse group of tree frogs, which includes representatives of Acris, Pseudacris, and Hyla. A recent comparative developmental study of Acris blanchardi and Pseudacris crucifer, two small non-arboreal species, found that despite their similar size, A. blanchardi exhibited reduced ossification and miniaturization patterns while P. crucifer did not. We examined the skeletal developmental of Hyla chrysoscelis as a baseline for the “typical” arboreal NA tree frog, to which A. blanchardi and P. crucifer can be compared. In H. chrysoscelis, ossification of elements associated with the central nervous system occurs first, followed by major elements of the fore- and hind limbs (associated with terrestrial locomotion), then structural elements of the adult nose and face, and finally elements of the suspensorium and jaws (associated with terrestrial feeding). Although this pattern is consistent with Acris and Pseudacris, the timing of ossification of some elements relative to one another and to external developmental changes is unique. For example, the onset of ossification of the entire postcranium occurs relatively sooner in development in H. chrysoscelis than in Acris and Pseudacris. Herein, we detail the ossification pattern of H. chrysoscelis, compare it to that of A. blanchardi, P. crucifer, and Hypsiboas lanciformis (a South American hylid), and comment on the skeletal evolution of NA hylids.