Morphologic Examination of Ossicula Auditus in Different Ruminants

Area of Science:

• Comparative anatomy
• Vertebrate morphology
• Auditory system evolution

Background:

• The ossicula auditus transmit sound vibrations from the tympanic cavity to the inner ear.
• This structure comprises the malleus, incus, and stapes.
• A lenticular bone (os lenticulare/processus lenticulare) is present in humans and most mammals.

Purpose of the Study:

• To conduct an in-depth comparative morphological study of the auditory ossicles in gazelles, sheep, and goats.
• To address the lack of published research on gazelle auditory ossicles.

Main Methods:

• Examination and stereomicroscopic photography of ossicula auditus from adult Awassi sheep, hair goats, and gazelles.
• Comparative analysis of morphological features across the three species.

Main Results:

• Auditory ossicles in all three species consist of malleus, incus, and stapes.
• Species-specific variations were noted in the malleus (articular surface, protrusions, manubrium mallei).
• The incus features a body and two crus, with the processus lenticulare on the crus breve in all species.
• The stapes bone exhibited a quadrangular shape, particularly in goats, characteristic of ruminants but less developed in other species.

Conclusions:

• The ossicula auditus of gazelles, hair goats, and Awassi sheep display significant morphological differences.
• These findings contribute to understanding the comparative anatomy and evolutionary adaptations of the auditory system in ruminants.