Beyond the sniffer: frontal sinuses in Carnivora

Area of Science:

• Mammalian anatomy
• Paleontology
• Biomechanics

Background:

• Paranasal sinuses are poorly understood cranial features with variable presence and form across species.
• Their primary function is debated, with hypotheses including opportunistic space-filling and improving skull strength by dissipating stress.

Purpose of the Study:

• To investigate patterns in frontal sinus size and shape disparity among Canidae, Felidae, and Hyaenidae using CT technology.
• To quantify the relationship between three-dimensional sinus shape and skull shape in these carnivore families.
• To provide quantitative data on sinus morphology for these three families.

Main Methods:

• Utilized CT technology to analyze frontal sinus morphology in Canidae, Felidae, and Hyaenidae.
• Employed a novel method to quantify the relationship between 3D sinus shape and overall skull shape.
• Correlated sinus size and shape with frontal bone morphology and skull allometry.

Main Results:

• Frontal sinus size and shape showed a stronger correlation with frontal bone size and shape than with overall skull morphology.
• Sinus morphology was related to allometric differences among families linked to biomechanical function.
• Results support the hypothesis that frontal sinuses opportunistically fill unnecessary space and can reduce feeding-related stress.

Conclusions:

• Frontal sinuses primarily fill mechanically unnecessary space but can enhance skull strength and dissipate stress.
• Sinus formation allows modification of skull function without compromising critical regions like the nasal chamber and braincase.
• This research provides quantitative insights into the functional morphology of carnivore skulls.