Dispersal forms are an important component of the ecology of many animals, and reach particular importance for predicting ranges of invasive species. African clawed frogs (Xenopus laevis) move overland between water bodies, but all empirical studies are from invasive populations with none from their native southern Africa. Here we report on incidents of overland movement found through a capture...

In order to gain insights into how the aortic arches changed during the transition of vertebrates to land, transformations of the aortic arches during the metamorphosis of Pelobates fuscus were investigated and compared with data from the early development of a recent ganoid fish Amia calva and a primitive caudate amphibian Salamandrella keyserlingi. Although in larval Pelobates, as in other no...

Postembryonic skeletal development of the pipid frog Xenopus laevis is described from cleared-and-stained whole-mount specimens and sectioned material representing Nieuwkoop and Faber developmental Stages 46-65, plus postmetamorphic individuals up to 6 months old. An assessment of variation of skeletogenesis within a single population of larvae and comparison with earlier studies revealed that ...

Culture of lymphocytes from adult Xenopus laevis (Daudin) (a pipid anuran amphibian) with mitogens (PHA, ConA, LPS and PWM) reveals a wide variation in the mitogen sensitivity of these cells: relatively high concentrations of mitogen are required to stimulate Xenopus lymphocytes compared with the concentrations appropriate for mammalian lymphocytes. Significantly better responses are obtained u...

To the respiratory physiologist or anatomist the diaphragm muscle is of course the prime mover of tidal air. However, gastrointestinal physiologists are becoming increasingly aware of the value of this muscle in helping to stop gastric contents from refluxing into the oesophagus. The diaphragm should be viewed as two distinct muscles, crural and costal, which act in synchrony throughout respira...

As frogs undergo metamorphosis from tadpole to adult, they may be susceptible decreases in locomotor performance and survival during stages which the tail limbs are both present. Because these alternative axial appendicular propulsive systems might interfere with each other, better when only one or other system predominates. This framework, termed ‘adaptive peak hypothesis’ emerged studies of g...