Bioacoustics of Speleomantes

Otic–occipitum complex ( Fig. 4A ) The otic–occipitum complex is generally smooth, with rounded and well-defined prominentiae semicircularis anterioris, posterioris and lateralis on the dorsal surface. Between them, a deep middle depression shows no minor foramina in its floor. The circular fenestra ovalis is covered in both dorsal and posterior views by the prominentia lateralis and posterioris, respectively. The latter is prominent in lateral view, between the cotyle and the fenestra ovalis, and a sulcus separates it from the opening of the fenestra ovalis. The dorsal edge of the fenestra is located at the mid-height of the complex, and its anterior edge is at the mid-length or slightly anterior. The parietal and parotic crests are absent or limited to a small and sharp, anteriorly pointing tip on the anterior part of the prominentia lateralis; the parotic process is also absent. The anterior edge of the tectum synoticum in medial view is located at the mid-length of the complex. The tectum is extended medially beyond the hypochordal commissure in posterior view, and beyond the prefacial commissure in dorsal view, but a concavity is visible between the two processes. The elliptical postoticum foramen is dorsal to the cotyle, surrounded posteriorly by the prominentia posterioris and the lamina of the tectum synoticum. The otic process and the processus basalis are not anteriorly projecting, but limited to flat, bean-shaped articular surfaces that are oriented anterolaterally. The sulcus petrosus is deep between them. The foramen faciale is visible on the lateral side, dorsolateral to the processus basalis, and it is the only foramen visible on the ventral surface of the complex. In anterior view, the basicapsular commissure is as medially developed as, or more medially developed than, the prefacial commissure. In anterior view, two foramina are present on the ventral half of the basicapsular commissure. The foramen prooticum is not completely surrounded by bone, and two additional foramina are visible in medial view in its concavity. The auditory cavity is deep, and the individual foramina for the different branches of the acoustic nerve are not visible. In ventral view, the sulcus is not clearly visible, and the hypochordal and basicapsular commissures are equally developed and irregular, with an indented margin between them, meaning that the fenestra basicranialis is not evident.