A. Channing et al., STATUS, VOCALIZATION AND BREEDING BIOLOGY OF 2 SPECIES OF AFRICAN BULLFROGS (RANIDAE, PYXICEPHALUS), Journal of zoology, 234, 1994, pp. 141-148
There is much confusion concerning the identity of bullfrogs in southe
rn Africa. Currently three subspecies are recognized, and introgressio
n has been suspected. We demonstrate that in southern Africa there are
two species: Pyxicephalus adspersus which has a long call, breeds dur
ing the day, and exhibits lek behaviour; Pyxicephalus edulis which is
smaller, has a short call, breeds at night and does not exhibit lek be
haviour.