Researchers using advanced micro-computed tomography have discovered undocumented anatomical complexes in the skull of the brown long-eared bat, Plecotus auritus. These specialized cranial structures modify both the maxillo-lacrimal region and parietal bone thickness.
Scientists examining the skeletal architecture of Plecotus auritus have identified a repeatable fenestration system. This system exists within the posterolateral region of the parietal bone.
The newly characterized surface is known as the Fenestras Elisabeth complex. It features a centrally located depression and larger openings. Numerous smaller perforations are also distributed across the bone.
Fenestras Elisabeth Complex Shows Stable Morphology
The complex consists of specific structural elements that appear consistently across specimens. Researchers analyzed ten skulls. These were kept in the reference collections of ISEZ PAN in Kraków and at the Natural History Collections Centre of the Institute of Biology of the University of Opole.
The analysis demonstrated stable, species-level anatomical traits.
- Fenestra Elisabeth: The primary broad, fenestrated surface spanning the posterolateral region of the parietal bone.
- Fenestrae parietales Elisabeth: Numerous individual openings varying in shape from oval to triangular and irregular.
- Fenestrula Elisabeth: Characteristic smaller component structures associated with the main surface.
- Recessus acousticus parietalis: A distinct recess observed alongside the clearly defined fissura occipitalis mastoidea.
Micro-CT scans revealed a clear thickness gradient across the bone. These scans were acquired using a Skyscan 1273 system at the Microtomography Laboratory of the University of Wrocław.
Cranial Structures Support Acoustic Needs
Brown long-eared bats rely heavily on echolocation. They possess exceptionally long, mobile external ears. Because of this, small modifications of the skull carry direct functional implications.
The complex likely reduces structural strain in the parietal lamina as the animal moves its elongated pinnae. This fulfills a mechanical role.
Fenestration patterns show individual variability and lateral asymmetry. This points to a high degree of adaptive plasticity in this cranial region.
New Bony Structures Appear in Maxillo-Lacrimal Region
Micro-CT analysis of the maxillo-lacrimal region in Plecotus auritus uncovered a consistent, bilaterally symmetrical configuration. This occurs at the junction of the maxillary and lacrimal bones.
This discovery includes an undescribed bony structure. It is designated as the processus intersuturalis maxillo-lacrimalis.
The surrounding region houses a distinct foramen orbitonasale accessorium, which is separate from the infraorbital foramen. It also contains a continuous canal termed the canalis maxillolacrimalis that opens into the nasal cavity.
These osteological features display high morphological repeatability across the examined specimens. Their exact functional significance is not yet known.