The Sequence of Cranial Ossification in the California Toad, Bufo boreas (Amphibia, Anura, Bufonidae)

Publisher Website
Google Scholar
Abstract
The order of appearance of skull bones in B. boreas is described. Skull bones appear in the following sequence: exoccipitals, parasphenoid, frontoparietals, premaxillae, prootics, squamosals, angulares, dentaries, septomaxillae, maxillae, nasals, pterygoids, prevomers, palatines, quadratojugals, mentomeckelians, columellae and sphenethmoid. Overall skull developmental patterns in B. boreas did not differ greatly from those in other generalized frogs. Differences were noted in the specific developmental patterns of the frontoparietal, exocciptal, columella, and sphenethmoid. Differences in overall developmental patterns were noted when comparisons were made with Xenopus laevis, Ascaphus truei, Osteopilus septentrionalis, Smilisca baudinii and Triprion petasatus. Comparisons among all of the species studied to date indicate several instances of fusion or loss of ossification centers in the skull of B. boreas. A comparison of osteogenesis in field-collected and lab-reared B. boreas revealed that even though growth patterns and sequence of appearance is the same in both groups, head bones develop significantly earlier in toads collected in the field. Head bones also developed earlier in toads collected in the Owens Valley of eastern California than in the San Fernando Valley of southern California [USA].

This publication has 0 references indexed in Scilit: