Skeletal structure as taxonomic tool for identification of mullet species (Teleostei: Mugilidae) from Aceh waters, Indonesia

Abstract

Many members of the mullets (family Mugilidae) are very similar morphologically, hence the possibility of taxonomic misidentification. This study involved the use of skeleton structure to distinguish four species of mullets, including Cremugil crenilabis, Liza macrolepis, Moolgarda engelii, and Mugil cephalus, harvested from Aceh waters, Indonesia. The mullets samples were collected from 10 locations, and a total of 10 samples were taken randomly as representatives of each species. The skeletal sample was prepared using the dry method. The results showed the presence of 8 pairs of ribs in C. crenilabis and L. macrolepis, while M. engelii had 9, with 10 in M. cephalus. In addition, the origin of the haemal canal of C. crenilabis is at the 12th vertebrae, extends to the 23rd, while for the other three species it starts at the 10th and extends to the 23rd. In addition, C. crenilabis possesses 12 haemal canals, but the rest have 14. The haemal canal is present in the last precaudal vertebrae of all specimens, except C. crenilabis, whose epural bone in the caudal skeleton is small and located far from the preural, while a larger and distinctly attached form is observed in the rest. Furthermore, L. macrolepis possess a pair of diapophyses, which laterally extend in the 2nd vertebrae. This bone is absent in the three other species. The presence of diapophyses, the number of ribs and haemal canals and the location of the epural bone in the caudal skeleton, and the condition of frontal attachment to the sphenotic are the important characters in distinguishing the four investigated species of mullets.