Complex sentence: The bony facial crest is an obvious candidate, and nasal diverticula may also have been present, inflatable soft-tissue sacs housed in the deep excavations flanking the crest and elongate holes for the nostrils.
Split into simpler sentences: The bony facial crest is an obvious candidate, and nasal diverticula may also have been present. These postulated diverticula would have taken the form of inflatable soft-tissue sacs housed in the deep excavations flanking the crest and elongate holes for the nostrils.