Skeletal malformation rates for several frog species were determined in a set of randomly selected wetlands in the north-central USA over three consecutive years. In 1998, 62 sites yielded 389 metamorphic frogs, nine (2.3%) of which had skeletal or eye malformations. A subset of the original sites was surveyed in the following 2 yr. In 1999, 1,085 metamorphic frogs were collected from 36 sites and 17 (1.6%) had skeletal or eye malformations, while in 2000, examination of 1,131 metamorphs yielded 16 (1.4%) with skeletal or eye malformations. Hindlimb malformations predominated in all three years, but other abnormalities, involving forelimb, eye, and pelvis were also found. Northern leopard frogs (Rana pipiens) constituted the majority of collected metamorphs as well as most of the malformed specimens. However, malformations were also noted in mink frogs (R. septentrionalis), wood frogs (R. sylvatica), and gray tree frogs (Hyla spp.). The malformed specimens were found in clustered sites in all three years but the cluster locations were not the same in any year. The malformation rates reported here are higher than the 0.3% rate determined for metamorphic frogs collected from similar sites in Minnesota in the 1960s, and thus, appear to represent an elevation of an earlier baseline malformation rate.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.