Morphological and molecular descriptions of Sphaeromyxa sevastopoli (Cnidaria) from host fishes from Sinop on the Black Sea coast.

Members of the genus Sphaeromyxa Thélohan, 1892 have been reported from a wide variety of fish species worldwide. In the present study, specimens of rusty blenny, Parablennius sanguinolentus, collected from Sinop on the Turkish Black Sea coast were investigated for myxosporean parasites by using both conventional and molecular methods. Sphaeromyxa sevastopoli Naidenova 1970 was the only myxosporean parasite found in the gall bladder of host fishes. The morphology peculiarities of obtained S. sevastopoli spores are in good agreement with those of original description and the morphometric data overlapped in spore length and width but differed in polar capsule length and width; however, they were within the ranges previously reported from 18 host fish species. Moreover, in the present study, molecular analysis of the 18S rDNA gene of S. sevastopoli isolate in our P. sanguinolentus as well as isolates from shore rockling Gaidropsarus mediterraneus and knout goby Mesogobius batrachocephalus which were previously morphologically identified and reported by Okkay and Özer (Acta Zool Bulg 72(1):123-130, 2020) was done for the first time and our three S. sevastopoli genotypes were allocated to the "balbianii" group which is characterized by straight or slightly curved and fusiform or ovoid spores with ovoid polar capsules.

Two novel myxosporean parasites in Black Sea fishes: Kudoa niluferi sp. nov. and Kudoa anatolica sp. nov. (Cnidaria: Myxosporea).

Members of the genus Kudoa are typically histozoic and only a few are coelozoic parasites, mainly in marine fishes. In the present study, 2 novel Kudoa species were recovered and described as Kudoa niluferi sp. nov. in the musculature of Neogobius melanostomus and Kudoa anatolica sp. nov. in the musculature, urinary bladder and kidney of Atherina hepsetus collected from the coast of Sinop on the Black Sea. Means ± SD (ranges) of mature spores of K. niluferi sp. nov. were 5.9 ± 0.1 (5.7-6.1) µm in length, 9.2 ± 0.2 (8.8-9.5) µm in width and 7.5 ± 0.3 (7.0-8.1) µm in thickness, while those of K. anatolica sp. nov. were 4.1 ± 0.3 (3.5-4.1) µm in length, 7.1 ± 0.2 (6.7-7.2) µm in width and 5.7 ± 0.2 (5.3-6.0) µm in thickness. In both parasite species, length and width of the 4 polar capsules were not equal and formed 3 distinct size classes, largest (1), intermediate (2) and smallest (1) in size. The prevalence and intensity of infection by K. niluferi sp. nov. were 12.8% and 20-29 parasites (per field-of-view, at 200× magnification), respectively, in the musculature of N. melanostomus. These values for K. anatolica sp. nov. were 32.1% and 10-19 parasites in the musculature as well as 2.9% and 20-29 parasites jointly in the kidney and urinary bladder of A. hepsetus. Phylogenetic analysis based on nuclear small subunit rDNA also suggested K. niluferi and K. anatolica as 2 novel species. These species appeared in the same lineage with K. nova and formed a Black Sea lineage.

Morphology and molecular phylogeny of Ortholinea mullusi sp. nov. (Myxozoa) in Mullus barbatus from the Black Sea.

Myxosporeans of the genus Ortholinea have a worldwide distribution and infect organs and tissues of exclusively marine fishes. Here we describe the morphological and molecular characteristics of Ortholinea mullusi sp. nov. parasitizing the urinary bladder and kidney tubules of red mullet Mullus barbatus collected from the coastal zone of Sinop in the Black Sea, Turkey. Polysporic plasmodia with immature spores were either elongate, 37.0 ± 4.5 SD (30-50) µm long and 45.0 ± 3.8 (40-55) µm wide, or were round, up to 100.0 µm in diameter. Mature, free spores were spherical in the frontal view and measured 9.3 ± 0.2 (9.0-9.7) µm in length, 8.7 ± 0.3 (8.2-9.3) µm in width and 7.7 ± 0.1 (7.5-7.9) µm in thickness. We observed 2 polar capsules of equal size, which measured 3.1 ± 0.1 (3.0-3.2) µm long by 2.5 ± 0.1 (2.4-2.6) µm wide, and the tips of the polar capsules were open towards the sutural line. The prevalence of infection by O. mullusi sp. nov. was 24.5%. Phylogenetic analysis based on nuclear small subunit ribosomal DNA (SSU rDNA) clearly suggested O. mullusi to be a new species, clustered within a lineage comprising O. labracis and O auratae. Pairwise nucleotide similarities and DNA distance values between O. mullusi sp. nov. and sister Ortholinea species also supported this suggestion.

Myxosporean parasites of Ceratomyxa merlangi and Myxidium gadi in whiting Merlangius merlangus: a comparative epizootiological analysis based on samples from two localities off southern and northern coasts of the Black Sea.

Totally 690 and 423 whiting Merlangius merlangus samples were collected from two localities off Southern (Sinop) and Northern coasts (Balaklava Bay) of the Black Sea, respectively, and examined for myxosporeans in the period from May 2011 to March 2014. Ceratomyxa merlangi and Myxidium gadi were the only myxosporean parasites identified in the content of gall bladder and their infection indices of prevalence (%) and intensity were calculated for length classes and sex of fish as well as for the seasons at both sampling localities. Overall infection prevalence of C. merlangi was 22.6% in Sinop and 27.9% in Balaklava samples while those values of M. gadi were 18.4% and 28.6% in Sinop and Balaklava samples, respectively. Both parasite species were also found to be co-existed in whiting samples. This is the first comprehensive epizootiological study yielded comparable data on C. merlangi and M. gadi infections in whiting in the southern and northern coasts of the Black Sea.

Molecular characterization and morphological aspects of Myxobolus parvus (Myxozoa) from Liza saliens (Mugilidae) off the Turkish Black Sea coasts.

Members of the phylum Myxozoa are among the most cosmopolitan parasites of fish, and the genus Myxobolus is the largest within the class Myxosporea in freshwater and marine environment from all over the world. Myxobolus parvus has been reported from mainly mugilid fishes from different localities including the Black Sea. Leaping mullet Liza saliens collected by fishermen off Sinop coasts of the Black Sea in the period between September 2014 and December 2015 was investigated for myxosporean parasites using conventional methods. M. parvus Schulman, 1962 was the only Myxobolus species identified and it was found in the gills, gall bladder, kidney tubules, and inside several cysts located on the lower jaw of examined fish in the present study. Morphometric data and all details of parasitic infection were determined and presented in tables and illustrated in figures. Molecular characterization was also conducted to reveal its position within Myxosporea. Two M. parvus samples from gills and kidney showed the same haplotype and appeared in the same sub-lineage with marine Myxobolus species. The closest haplotypes to M. parvus were Triactinomyxon sp. and Endocapsa sp. which are the actinosporeans forms of unknown myxozoan species. These data are the first in molecular characterization of M. parvus, its occurrence in lower jaw of leaping mullet along with its infection prevalence values off the Turkish Black Sea coasts.

Morphology, histology and phylogeny of Henneguya sinova sp. nov. (Myxobolidae: Myxozoa) infecting gills of Parablennius tentacularis in the Black Sea, Turkey.

Myxosporeans of the genus Henneguya have a global distribution and infect organs and tissues of both marine and freshwater fishes. Here we describe the morphological, histological and molecular characteristics of Henneguya sinova sp. nov. parasitizing the gill arches of tentacled blenny Parablennius tentacularis (Perciformes: Blenniidae) collected from the coast of Sinop on the Black Sea in Turkey. Several oval whitish plasmodia of different sizes in the gill arches of fish were found. The mature spores were rounded oval in frontal view, with a mean (range) total length 57.5 (51.5-68.0) µm; the spore body was 11.7 (11.3-12.0) µm in length by 7.6 (7.3-8.3) µm in width and 6.7 (6.6-6.8) µm in thickness. The caudal appendages, measuring 46.0 (40.0-55.0) µm in length, were very thin at the tapered end. The prevalence of infection by H. sinova sp. nov. was 35.5%. Phylogenetic analysis of nuclear small subunit ribosomal DNA (SSU rDNA) clearly suggested H. sinova as a new species which is clustered within the marine Henneguya lineage. Pairwise nucleotide similarities and DNA distance values of SSU rDNA between H. sinova sp. nov. and other related Henneguya species also supported this suggestion.

Levels of infection and seasonal occurrence of Gyrodactylus alviga (Monogenea: Gyrodactylidae) on the whiting Merlangius merlangus off the Turkish and Russian coasts of the Black Sea.

Gyrodactylus alviga is a generalist species reported in many Black Sea fish species, but whiting is known to be its main host. It is the only monogenean parasite that has been reported so far on the skin, fins and gills of whiting Merlangius merlangus in the Black Sea. A total of 690 fish from Turkey and 423 fish from Russia were examined to detect parasites. Infection indices of prevalence, mean intensity and mean abundance values were calculated for length classes and sex of fish, as well as for the seasons. There is a gradual increase in infection indices in relation with increasing host length classes and there are higher infection indices on female fish. Furthermore, despite lower prevalence indices in spring and winter, higher parasite intensity values were determined in these seasons. It is concluded that larger fish provided more space and food for G. alviga, and female fish were more parasitized as they were more active in searching for food, which enables the parasite to switch between hosts. In addition, winter and spring were more appropriate for reproduction of G. alviga.

Study of Myxosporea (Myxozoa), infecting worldwide mullets with description of a new species.

Existing data on Myxozoa parasites infecting mullets were reviewed. The validity of nine species names was updated. Sixteen species were registered during analysis of original material collected in the Mediterranean, Black, Azov, and Japan Seas in 2004-2005. A new bivalvulid myxozoan parasite, Myxobolus adeli n. sp., was described from the inner organs of the golden grey mullet Liza aurata (Risso, 1810) collected in the Mediterranean (Ebro Delta, Spain), Black Sea (Kerch Strait, Ukraine), and Azov Sea (Genichesk, Ukraine) coastal waters. It is characterized by the presence of elongated, spindle-like cysts 0.5-1.3 mm in size, filled with wide transverse-oval spores about 6.2 × 7.2 × 4.6 µm in size, with two equal polar capsules measuring about 3.0 × 1.8 µm and short polar filament, turned into four coils. The obtained data show that this species differs from all previously described Myxobolus spp. with equal polar capsules. Comparative study of Myxobolus spp. recorded in worldwide mullets indicates a close relationship with M. adeli n. sp. and Myxobolus improvisus Isjumova, 1964 registered in mullets. Probably, the last species includes representatives of some different species, infecting freshwater and marine hosts.

Kudoa unicapsula n. sp. (Myxosporea: Kudoidae) a parasite of the Mediterranean mullets Liza ramada and L. aurata (Teleostei: Mugilidae).

A new multivalvulid myxozoan parasite, Kudoa unicapsula n. sp., is described from the intestinal mesentery, intestine and pyloric caeca of the thin-lipped grey mullet Liza ramada (Risso 1826) and the golden grey mullet L. aurata (Risso, 1810) from the Mediterranean coastal waters of Spain. It is characterized by the presence of elongated, rice corn-like white cysts of 0.47-0.56 x 0.18-0.38 mm, filled with tetracapsulate, slightly asymmetric spores, rectangular in apical view and tear-shaped in lateral view with four polar capsules of considerably different size and slightly unequal spore valves with rounded edges, overlapping each other on the apex of the spore. One large polar capsule includes a polar filament coiled in two to three turns, and the other three polar capsules, which are very small, posses only a rudimental filament. Both light and electron microscopy data showed that this species differs from all previously described Kudoa spp. with unequal polar capsules. The molecular analysis based on 18S and 28S ribosomal deoxyribonucleic acid DNA sequence data of K. unicapsula n. sp. indicates a close relationship and thus phylogenetic clustering together with K. trifolia, a myxozoan from the same host and the same geographical location.