An Introduction to the Comparison Shape of some Cranial Structures in Boleophthalmus Dussumieri and Periophthalmus Waltoni (Teleostei: Oxudercidae) in the Persian Gulf: An Exploratory Analysis with Micro-CT Scanning

Abstract

Purpose: The osteological characteristics of fish, especially the head structure, are important in understanding the biological characteristics. Periophthalmus waltoni and Boleophthalmus dussumieri are among the mudskippers and are distributed along the coasts of the Oman Sea and the Persian Gulf.

Materials and Methods: After catching and fixing the samples in 96% ethanol, the samples were then sent to the preclinical laboratory (Lotus-InVivo) for micro-CT scanning (TPCF, in Tehran university of medical sciences) for imaging.

Results: In B. dussumieri, the skull is rudimentary and a high percentage of the bones is still cartilaginous. In this species, despite the larger head size, the braincase is small. In P. waltoni, the braincase is larger, but the skull tissue is completely bony and has very little cartilaginous. The jaws have also undergone drastic changes, corresponding to the change from a nearly fixed biting mouth to a flexible sucking mouth. In both species, the teeth are sharp and in two parts in the jaws. In P. waltoni, there are three pairs of sharp teeth for hunting in the upper jaw, the number of these teeth in B. dussumieri is four passes and it is less curved.

Conclusion: In this report, for the first time, the skull structure of the Persian Gulf was investigated. Micro CT technique has also been used for the first time. Mudskippers have developed special adaptations to live in mud in terrestrial and aquatic conditions. These adaptations are greater in P. waltoni, which shows greater degrees of terrestrialization, and requires detailed studies in this field.