Preliminary Investigation of the Ocular Macroscopic Structure of a Bowmouth Guitarfish (Rhina ancylostoma Bloch & Schneider 1801)

Bowmouth guitarfish is one of the rare and endangered aquatic species [1] in class Chondrichthyes, subclass Elasmobranchii, which includes sharks and rays (Batoidea), order Rajiformes, and the only species in the family Rhinidae and genus Rhina [2]. Its habitats include the Indian and the Pacific oceans and have been reported from Australia to the south of the Arabian Peninsula. An adult guitarfish can measure up to 2.7 m and weigh 135 kg. Its most prominent features are thorny ridges on its dorsum (one median ridge and two lateral ridges). There are also two pairs of small ridges; one pair craniomedial to the lateral ridges and the other pair caudal to the lateral ridges [3]. Its torso resembles that of a shark, hence another common name “shark ray”. The eyes are located within eye sockets immediately below the cranial end of each lateral ridge. There is also a clearly defined spiracle caudal to the eye socket, which connects to the oral cavity [4].