Courtship behaviors are species-specific and function as a mechanism for reproductive isolation. The neural circuitry underlying courtship behavior, however, may be shared among closely-related species. Here we analyzed the neural circuitry underlying courtship vocalizations of the genus Xenopus. To attract females, male Xenopus produce courtship vocalizations that consist of clicks repeated at species-specific temporal patterns, generated by the central pattern generators (CPGs) contained in the brainstem. In Xenopus laevis, a male advertisement call contains two vocal phases, fast and slow trill with clicks repeated at a fast (~70Hz) and a slow (~30Hz) rate, respectively. Previously, we discovered that fast and slow trills of male X. laevis are produced by anatomically distinct neural circuitry in the brainstem. The fast trill CPGs rely on the ascending projection from the motor to the premotor nuclei, but not the slow trill CPGs. When the projection between the nuclei are unilaterally transected, fast trills become disorganized while slow trills remain intact. To determine a role of the ascending projections between motor and premotor nuclei in the production of courtship vocalizations in other species of Xenopus, we performed unilateral transection in X. tropicalis and X. petersii with calls made of trills containing clicks repeated at slow and fast trill rates, respectively. The results showed that vocalizations of X. petersii but not of X. tropicalis were affected by the transection, indicating that the projections between the nuclei are important for fast but not for slow trill generation in other species of Xenopus. Interestingly, the synapses between laryngeal motor neurons to premotor nuclei are glutamatergic. These results suggest that the neural circuitry for fast and slow trills is shared between species of Xenopus, although the exact vocalizations differ between the species.