Abstracts 2011 - Framingham State University

Jennifer Melgar
Development and Malformations of
the Vertebral Column of Hyla
chrysoscelis.
Hyla chrysoscelis belongs to the family Hylidae, which is one of the most species-rich
families of amphibians. Although the life history and biogeography of H. chrysoscelis
has been documented, very little is known about its skeletal anatomy and
development. Typically, descriptions of the anuran skeletal system focus mainly on
adult anatomy, leaving out evident morphological and developmental specializations.
Furthermore, there is very little information on the variation of the ontogeny of
osteological features within a species. However, a recent study of Acris crepitans, a
derived hylid, described unique trends in skeletal ossification and previously
undocumented variations in vertebral skeletal anatomy. Interestingly, in Acris
crepitans, the centra have malformed articular surfaces. In addition, the vertebral
column of A. crepitans also has a developmental abnormality where the centrum and
the postzygapopphyses of Presacral VIII are fused to the centrum of the sacrum, and
the urostyle is fused to the sacral vertebrae. Hyla chrysoscelis is a poorly understood,
close relative of A. crepitans. Herein I describe the vertebral development of H.
chrysoscelis, and although no malformations were observed, 5% of the Hyla
chrysoscelis specimen showed left-right asymmetries in the ossification pattern of the
vertebrae. These results suggest that the axial variation present in A. crepitans is a
derived character for that species and it may not be common among other hylids.
100 Hyla chrysoscelis tadpoles
Fixed and stored in 10% buffered formalin
Each specimen staged according to Gosner
and snout-vent length
Specimen cleared and stained
◦ Dehydrated in ethanol, cleared
and stained with Alcian Blue
and Alizarin Red
Degree of Ossification
4
3.5
3
2.5
2
1.5
1
0.5
0
-0.5
-1
y = 0.1802x - 5.0386
R² = 0.8786
25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45
Gosner Stage Rs = 0.9374
P value =