First report of morphological characterization of rare males and Sexual Dimorphism in parthenogenetic Artemia (Crustacea: Anostraca): an evolutionary approach

First report of morphological characterization of rare males and Sexual Dimorphism in parthenogenetic Artemia (Crustacea: Anostraca): an evolutionary approach

Behrooz Atashbar*¹, Alireza Asem² and Nasrullah Rastegar-Pouyani³

1) Artemia and Aquatic Animals Research Institute, Urmia Uni, Urmia, Iran
2) Protectors of Urmia Lake National Park Society (NGO), Urmia, Iran
3) Department of Biology, Faculty of Science, Razi University, Kermanshah, Iran

Summary:
Parthenogenetic populations of Artemia have two important characters; their reproductive mechanism is only via parthenogenesis and also the males seldom are produced in these specimens, so, the male samples are unproductive. This is the first study on morphological and biometrical characterization of the males and sexual dimorphism in parthenogenetic populations of Artemia carried out in the Urmia Lake, Iran. Thirty male samples were collected during five months with less than 0.4% frequency and were compared with thirty female samples. The morphological structure of frontal knob in the males of the parthenogenetic population from the Uremia Lake is recognized by its subspherical shape Also the structure of furca is represented by having two lobed with many setae (Fig 1). Twelve morphometric common characters between males and females were measured. Principal Components Analysis shows that male and female groups are separated completely. The first and second components show 66.45% and 14.56% of the total variation respectively; in total the two components show 81.02% of variation. Discriminant Function Analysis confirms 100% of the original groupings. Female is bigger than the male; so, This result can prove; at less parthenogenetic population of Artemia from Urmia Lake could keep its ancestral and evolutionary characters; because the parthenogenetic Artemia populations are new specimens that had been separated from bisexual species of Artemia.

Figure 1. The structure of frontal knob: subspherical shape (left) and furca: tow lobed with many setae (right) in parthenogenetic population Artemia from the Urmia Lake.

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