Computed tomographic analysis of internal structures within the nasal cavities of green, loggerhead and leatherback sea turtles

Abstract

The morphology of the tetrapod nasal cavity has adapted to the environment in terms of olfaction and respiration. Reports indicate that the internal structure of the nasal cavity of green sea turtles is more complex than that of turtles in general, but whether or not it is similar among sea turtle species remains unknown. The present study aimed to define the internal structures of the nasal cavity of green (Chelonian mydas), loggerhead (Caretta caretta) and leatherback (Dermochelys coriacea) sea turtles using computed tomography. The nasal cavity of green and loggerhead sea turtles contained anterodorsal, anteroventral, posterodorsal diverticula and a posteroventral excavation in the middle. In contrast, the nasal cavity of leatherback sea turtles had more complicated dorsal region comprising anterodorsal and posterodorsal diverticula, and two excavations between the nostril and anterodorsal diverticulum, but no distinct structures at the ventral region. The airway in the nasal cavity was shorter and thicker in the leatherback, than in the green and loggerhead turtles. These species differences might reflect ecological variety and different evolutionary strategies.

Anatomic Interactive Atlas of the Loggerhead Sea Turtle (Caretta caretta) Head

“…Therefore, precise knowledge of the anatomy of the sea turtle head is necessary to also contribute to the establishment of correct diagnoses. In order to obtain clinical images of the head, CT and magnetic resonance imaging have progressively gained credit for their ability to provide more data to assess the osseous and soft tissue structures of this region [ 3 , 4 , 7 , 33 , 46 , 47 ]. Diagnostics of several diseases involving the head of loggerhead sea turtles can be improved using CT imaging [ 7 , 33 , 47 ].…”

“…In addition, MPR sagittal images were obtained using bone and soft tissue kernels. The planimetric CT anatomy of the head allows a correct morphologic and clinical assessment of its anatomic structures in the loggerhead sea turtle [ 3 , 7 , 33 , 46 , 47 ]. The sagittal MPR kernel plane provided the best views of the midline structures of the head, whereas the transverse plane allowed us to better observe the anatomic relationships of the anatomic structures.…”

“…Sea turtle conservation has been taken up as a goal by several scientific and academic disciplines, including veterinary medicine [ 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 ]. The 2D model presented in this research provides a novel, accessible, valuable, intuitive, and interactive anatomic resource for studying the head of the loggerhead sea turtle.…”

“…Currently, the loggerhead turtle is considered as Vulnerable under IUCN Red List criteria, showing a decreasing trend in population globally [ 2 ]. Anatomic, physiologic, clinical, and pathologic studies on stranded sea turtles are essential activities for sea turtle conservation around the world [ 3 , 4 , 5 , 6 , 7 ]. Furthermore, in recent decades, the number of veterinary surgeons involved in sea turtle conservation in wildlife rehabilitation hospitals has increased notably [ 6 ].…”

Behavioral effects of scents from male mature Rathke glands on juvenile green sea turtles (<i>Chelonia mydas</i>)

“…This behavior was also evident in green sea turtles reared at the Ogasawara Marine Center (OMC) (Supplementary Video), especially when they encountered unfamiliar foods. We previously reported that sea turtles possess the morphologically-complicated nasal cavity [15,16,32] and that areas where water easily and hardly enters in the nasal cavity of green sea turtles are lined with different types of sensory epithelia [15], indicating that airborne and waterborne odors play important roles in their behaviors. In fact, sea turtles can detect airborne and waterborne odors [5,20].…”