Table 2.

Principal anatomical terms of the nasal region of cetaceans used in the present work

Term used	Synonyms	Definition	References
Nasal passage		The whole passageway for air between the blowhole and the internal bony nares including vestibule and nasal chamber. This can be divided into upper and lower nasal passage	This contribution
Upper nasal passage		The portion of the nasal passage which includes the blowhole, vestibule, external bony nares and nasal fossa	This contribution
Lower nasal passage		The portion of the nasal passage which includes the nasal chamber and the internal bony nares	This contribution
Blowhole	Fleshy nostril	External opening of the respiratory apparatus in the skin formed by an external and inner margin	Mead & Fordyce (2009, pp. 156) and Witmer (2001)
Vestibule	Vestibule	Cavity generated with the opening of the blowhole for the passage of the air placed immediately below the blowhole	Henry et al. (1983) and this contribution
Nasal chamber	Olfactory chamber, nasal cavity	Recess of the nasal passage which contains the turbinates	Thewissen et al. (2011, pp. 5)
Internal bony nares	Internal nares, choanae, posterior nares	Internal or posterior opening of the nasal passage, formed by the pterygoid and vomer	Mead & Fordyce (2009)
Nasal plug		Soft structure, valve-like, formed by connective and adipose tissue and nasal muscles which occlude the nasal passage	Heyning & Mead (1990, pp. 69)
Nassal fossa		Bony fossa on the dorsal surface of the skull formed by the premaxillae, vomer, nasal and nasal septum which hold the soft structures of the upper nasal passage (the principal are the nasal muscles), epithelium, blowhole and vestibule	This contribution
External bony nares		Distal or external bony opening of the respiratory apparatus associated with the nasals and premaxillae	Mead & Fordyce (2009)