فاطمه نظری

In this study, the instability of morphological characters in adult females of Parvocalanus crassirostris (F. Dahl, 1894) is evaluated. More than 28 types of fifth legs were observed in female individuals of P. crassirostris, showing variation in shape, segmentation, spine-like setae size, and the presence or absence of spines on the legs. Compared to other diagnostic characters, this trait is considered to have low value due to its observed morphological variations. Additionally, diversity was observed in the ornamentation of the outer border of exopods 2 (Exp2) and 3 (Exp3), with different serration patterns on the second to fourth legs. Molecular analysis using the partial CO1 gene showed that all individuals, regardless of intraspecific variation in the type of modified fifth legs, belong to P. crassirostris. All observed morphs are described in this study to provide informative data for evaluating diverse character types. Among state-of-the-art methods, the confocal laser scanning microscope was used to examine this phenotypic diversity and to explore the main patterns and hypotheses related to the factors possibly affecting morphological trait inconsistencies in this species.