Alireza Asem

Genetic variation and evolutionary origins of parthenogenetic Artemia (Crustacea: Anostraca) with different ploidies

Using two nuclear (ITS1 and Na+/K+ ATPase) and three mitochondrial (COI, 16S and 12S) markers, we determined the genetic variation and evolutionary relationship of parthenogenetic and bisexual Artemia. Our analyses revealed that mitochondrial genes had higher genetic variation than nuclear genes and that the 16S showed more variety than the other mitochondrial genes in parthenogenetic populations. Triploid parthenogens showed lower genetic variation than diploid ones, whereas the tetra‐ and pentaploids had greater genetic distance than diploid parthenogens. No shared haplotype was found between individuals of parthenogenetic populations and Asian bisexual species with the exception of Na+/K+ ATPase (Artemia tibetiana). Only mitochondrial markers can demonstrate phylogenetic relationships, and showed that the parthenogenetic Artemia is a polyphyletic group in which the diploid lineages share a common ancestor with Artemia urmiana while tetraploids are closely related to Artemia sinica. The triploid and pentaploid linages are likely to be directly derived from diploid and tetraploid parthenogens, respectively. Subsequently, west Asia is origin for di‐/triploids, and tetra‐/pentaploids rose from East Asia.

Morphological differentiation of seven parthenogenetic Artemia (Crustacea: Branchiopoda) populations from China, with special emphasis on ploidy degrees.

Parthenogenetic Artemia from seven Chinese locations with different elevations and various ploidies are characterized by phenotypic and morphometric analyses. Our findings show that the studied populations exhibit dissimilar patterns of ovisac. Four phenotypic patterns of furca are qualified and one of them is shared among di‐, tetra‐ and pentaploid Artemia. Results of discriminant analysis based on morphometric data reveal that tetra‐ and pentaploid populations are grouped together, but the Aqqikkol Lake population is clearly differentiated. Previous hypothesis/conclusion that polyploid Artemia are larger than diploids is only partly supported by the present results, which show that pentaploid and tetraploid populations are larger than the mostly diploid populations in terms of the total length, but the body size of the Aibi Lake triploids has not significant difference with the sympatric diploids and the mostly diploid Aqqikkol population that inhabit in very high altitude has the largest body size among all parthenogenetic populations. The founding confirms that body size of Artemia is following with Bergmanns rule. Microsc. Res. Tech. 79:258–266, 2016.

[Comparison of the diameter of the frontal knobs in Artemia urmiana Günther, 1899 (Anostraca), Comparison of the diameter of the frontal knobs in Artemia urmiana Günther, 1899 (Anostraca)]

[In four samples of Artemia urmiana Gunther, 1899 from Urmia Lake, Iran, the following parameters were compared: the diameter of the frontal knobs (right and left), and the respective ratios of that diameter with total body length and head width. The results do not denote significant differences in frontal knob diameter that would agree with similar results observed in frontal knob diameter in populations of A. franciscana Kellogg, 1906 and A. persimilis Piccinelli & Prosdocimi, 1968. However, we report differences in the other parameters studied for each of the populations studied, that could be explained by the environmental heterogeneity of the studied site. Ecological, biogeographical, and systematic issues related with the results are discussed. Para cuatro poblaciones de Artemia urmiana Gunther, 1899 del lago Urmia, Iran, se compararon los siguientes parametros: diametro de los lobulos frontales (derecho e izquierdo), y las razones respectivas de los diametros con el largo total del cuerpo y el ancho de la cabeza. Los resultados no mostraron diferencias significativas entre los diametros del lobulo frontal, lo cual seria similar a resultados observados para poblaciones de A. franciscana Kellogg, 1906 y A. persimilis Piccinelli & Prosdocimi, 1968. Por otro lado, hubo diferencias significativas para los otros parametros estudiados para las poblaciones estudiadas, lo cual se deberia a la heterogeneidad ambiental del sitio estudiado. Se discutieron topicos de ecologia, biogeografia y sistematica relacionados con los resultados obtenidos en el presente estudio., In four samples of Artemia urmiana Gunther, 1899 from Urmia Lake, Iran, the following parameters were compared: the diameter of the frontal knobs (right and left), and the respective ratios of that diameter with total body length and head width. The results do not denote significant differences in frontal knob diameter that would agree with similar results observed in frontal knob diameter in populations of A. franciscana Kellogg, 1906 and A. persimilis Piccinelli & Prosdocimi, 1968. However, we report differences in the other parameters studied for each of the populations studied, that could be explained by the environmental heterogeneity of the studied site. Ecological, biogeographical, and systematic issues related with the results are discussed. Para cuatro poblaciones de Artemia urmiana Gunther, 1899 del lago Urmia, Iran, se compararon los siguientes parametros: diametro de los lobulos frontales (derecho e izquierdo), y las razones respectivas de los diametros con el largo total del cuerpo y el ancho de la cabeza. Los resultados no mostraron diferencias significativas entre los diametros del lobulo frontal, lo cual seria similar a resultados observados para poblaciones de A. franciscana Kellogg, 1906 y A. persimilis Piccinelli & Prosdocimi, 1968. Por otro lado, hubo diferencias significativas para los otros parametros estudiados para las poblaciones estudiadas, lo cual se deberia a la heterogeneidad ambiental del sitio estudiado. Se discutieron topicos de ecologia, biogeografia y sistematica relacionados con los resultados obtenidos en el presente estudio.]

A note on the biogeographical origin of the brine shrimp Artemia urmiana Günther, 1899 from Urmia Lake, Iran

The brine shrimp Artemia urmiana, an abundant inhabitant of the hypersaline Urmia Lake in northwestern Iran, has recently been described from Lake Koyashskoe, also a shallow hypersaline lake that is located on the Black Sea coast of the Crimean Peninsula (Ukraine). This discovery has questioned the endemicity of A. urmiana in Urmia Lake and has also brought into question the biogeographical origin of this species. In the present study, we combined recent genetic divergence data (mtDNA-COI) with palaeoecological evidence to address the biogeographical origin of A. urmiana. Calibration of the molecular clock of the COI region was set by assigning the age of the micro-crustacean Daphnia pulex minimally at 145 Mya. The divergence age of A. urmiana in Urmia Lake dates back to 383,000 years, whereas Ukrainian Artemia reflects a very young populations that diverged about 196,000 years ago. Palaeoecological evidence suggests that the age of the major habitat of A. urmiana i.e. Urmia Lake goes back to the Tertiary Period while the Ukranian habitats of the species are very young, by virtue of geological features of the Holocene age. We conclude that the biogeographical origin of A. urmiana is outside of Europe and the current state of knowledge strongly suggests that Urmia Lake has been the major source of its expansion into its modern habitats in Europe.

SEM study of diversity in the cyst surface topography of nine parthenogenetic Artemia (Crustacea: Anostraca) populations from China

The cysts of nine Chinese populations of parthenogenetic Artemia were studied by scanning electron microscope. In the 270 cysts examined, 15 different morphological patterns were recognized with most of them not recorded in previous studies and the “tubercled shell surface” being the most common pattern. Results also displayed high intrapopulation variability, with the maximum of 11 patterns (in 30 cysts) recorded from the Barkol population. No positive correlation between the diversity of cyst shell patterns and ploidy compositions was found. Principal components analysis suggests higher similarity among coastal populations than among inland populations, which may be attributed to the identity of physicochemical conditions among coastal salterns and dissimilarity among inland saline lakes. Microsc. Res. Tech. 77:1005–1014, 2014.