Muscle Development in the Abdominal Region of Larval Hylidae (Amphibia: Anura)

MANZANO AS; PEROTTI MG.

JOURNAL OF MORPHOLOGY

WILEY-LISS, DIV JOHN WILEY & SONS INC

Lugar: New York; Año: 1999 vol. 241 p. 275 - 282

0362-2525

Larval muscle development in the abdominal region of five species of hylid frogs (Scinax nasicum, S. fuscovarium, Hyla andina, Phyllomedusa boliviana, Gastrotheca gracilis) was studied using differential staining techniques.  These five species represent three major hylid subfamilies.  The development of the main abdominal muscles, the rectus abdominis, the two lateral muscles (obliquus externus and transversus), and the lateral pectoralis abdominalis is described.  The number of myotomes of the rectus abdominis varies between five and six, and the abdominal muscles associated with the rectus abdominis (obliquus externus, pectoralis abdominalis, and rectus cervicis) vary interspecifically in time of appearance and configuration. The presence of gaps in the configuration of the rectus abdominis has been related to the lotic habits of the larvae.  However, our observations indicate the presence of such gaps in larvae that inhabit lentic environments as well.  These results suggest that the presence of these gaps is unrelated to larval habitat.  The relatively small differences in muscle morphology among these closely related species, which apparently cannot be explained by morphological adaptations related to their ecology, could be attributed to heterochrony.  In the species studied, the number of elements that form the abdominal musculature in larvae is equal to that observed in adults.  Likewise, the general morphology of the muscles is ontogenetically conserved.  This suggests that both the axial skeleton and musculature are more ontogenetically conserved in relation to the substantial changes that are observed in the skull and head muscles of developing anurans.