The comparative skeletal structure of blenniella bilitonensis (Skippers) and bathygobius fuscus (Remainers)

Abstract

Intertidal Zone is an area with high biological diversity including vertebrates. In order to survive in area with rapid change of environmental condition, animals need to be adapted accordingly. One type of adaptations that mostly employed is structural adaptation specifically ones that related to locomotor performances. Differences on how to navigate during high tides or when the water level subsided as well as types of locomotion between skippers and remainers suggested that there might also be structural differences in their skeleton. This research is aimed to study the skeletal structure of two species that use different strategy in their locomotion. Two species of fish from two main groups of intertidal fish (skippers and remainers) were caught and preserved in 96% Ethanol. The skeletal preparation was made using Inouye's Alizarin Red Alcyan Blue Method. Data were collected by comparing skeletal structure between two species particularly the axial (vertebrae) and appendicular (pelvic, pectoral, caudal fin) skeleton. Based on the observation, skippers and remainers skeletal features has been adapted to different function during locomotion. Modifications on pelvic, pectoral and caudal bones were found in skippers and remainers. In B. bilitonensis, there are fusion of bones, reduction of some structures and also smaller bone area to provide agility. In remainers, modification mostly found in pelvic and pectoral fin. Pelvic fins possess larger and more rigid basal lepidotrichia as it was used as an attachment apparatus while fish cling to the substrate during high tide. In B. fuscus, pectoral fins are used as main propellers during swimming instead of caudal fins, hence larger bones area to provide more muscle attachment are observed in this species,