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Morphological variability of otolith organs in three congeneric Pagellus species

Bostanci Derya, Yedier Serdar, Türker Dilek, Işmen Ali

Oceanological and Hydrobiological Studies

2024

Vol. 53, No. 1

88--101

Morphological features of sagittal otoliths in Pagellus acarne, P. bogaraveo, and P. erythrinus samples collected from the Aegean Sea were used to assess the variability both between Pagellus species and between otolith pairs employing scanning electron microscopy (SEM) and contour shape analysis. Twenty-one otolith morphological characters were compared in detail using SEM analysis. Twelve of these characters differ between Pagellus species and are suitable for distinguishing between the three congeneric Pagellus species. Wavelet functions of otolith contour shape were compared for six Pagellus groups. The wavelet functions obtained from the contour shape analysis showed high variability in the antero-dorsal, postero-dorsal, and antero-ventral regions of otoliths among the six groups analyzed. The results of principal component analysis (PCA) of the wavelet data provided a clear distinction between the groups under study. Cluster analysis supported the PCA results and basically divided them into two main branches. One of these branches contained only P. erythrinus, while P. acarne and P. bogaraveo were present in the other branch. This is the first study to provide detailed morphological characters and wavelet analysis of left- and right-side otoliths in these three congeneric Pagellus species from the Aegean Sea.

Ornamentation of dermal bones of Placodermi from the Lower Devonian of Morocco as a measure of biodiversity

Antczak M., Berkowski B.

Geologos

2017

Vol. 23, No. 2

65--73

Dermal bones are formed early during growth and thus constitute an important tool in studies of ontogenetic and evolutionary changes amongst early vertebrates. Ornamentation of dermal bones of terrestrial vertebrates is often used as a taxonomic tool, for instance in Aetosauria, extant lungfishes (Dipnoi) and ray-finned fishes (Actinopterygii), for which it have been proved to be of use in differentiating specimens to species level. However, it has not been utilised to the same extent in placoderms. Several features of the ornamentation of Early Devonian placoderms from Hamar Laghdad (Morocco) were examined using both optical and scanning electron microscopy to determine whether it is possible to distinguish armoured Palaeozoic fishes. Four distinct morphotypes, based on ornamentation of dermal bones, are dif-ferentiated. These distinct types of ornamentation may be the result of either different location of dermal plates on the body or of ontogenetic (intraspecific) and/or interspecific variation.