Monotypic. Note that Austen's Brown Hornbill Ptilolaemus austeni was formerly considered conspecific with Ptilolaemus tickelli but is now separated as a full species.
Dickinson, E. C. & Remsen, J. V. Jr., Editors (2013) The Howard and Moore Complete Checklist of the Birds of the World 4th edition, Vol. 1 Non-passerines. Aves Press, Eastbourne, UK
Kemp, A.C. (1995) The Hornbills: Bucerotiformes. Bird Families of the world. i‐xvi, 1‐302. – Oxford University Press,