Morphometric analysis of four species of Eubothrium (Cestoda: Pseudophyllidea) parasites of salmonid fish: An interspecific and intraspecific comparison

A review of the Anatolian Gomphocerus Thunberg, 1815 (Orthoptera: Acrididae: Gomphocerinae) via morphological and bioacoustics characters: data suggesting a new species, a new subgenus and three new statuses

Gomphocerus Thunberg, 1815 (Orthoptera, Acrididae, Gomphocerinae) is an interesting genus with clavate antennae, differing from the other genera by the pyriform (pear-shaped) anterior tibiae in the male and being represented by 17 taxa species-subspecies in the Palaearctic region. Anatolian species of this genus have not been adequately studied, and almost all of them are cold tolerance species and live in high mountain meadows. The previous studies indicate that the taxa belonging to Gomphocerus have some taxonomic problems in both Turkey and the Palaearctic region. For this reason, the genus needs taxonomic revision due to its biogeographical, biodiversity, taxonomical and faunistic issues for which morphological and bioacoustics characteristics are to be used. This study was carried out between the years 2015 and 2021 at different altitudes and habitats of the mountains, where Gomphocerus specimens were collected from various localities in Anatolia. Since the species belonging to the genus have distinct morphological differences, the genus is divided into two subgenera: the nominate subgenus and a new subgenus Bolivarianus Mol, subgen. n. In addition, a new species of the nominate subgenus Gomphocerus (Gomphocerus) eyluldenizi Mol, sp.n. is described from Erzurum province (Eastern Anatolia) and when both morphology and bioacoustics characteristics are evaluated, three subspecies of the genus distributed in Anatolia are designated at species level: Gomphocerus (Gomphocerus) turcicus Mistshenko, 1951 stat. n. et sp. rev., Gomphocerus (Bolivarianus) acutus Karaba, 1957 stat. n., and Gomphocerus (Bolivarianus) hemipterus Karaba, 1953 stat. n. Furthermore, a key to the subgenus and species level for Anatolian members of Gomphocerus is provided with original figures, a distributional map and suggestions for conservation status according to IUCN categories are presented.

Systematics and diversification of Anindobothrium Marques, Brooks & Lasso, 2001 (Eucestoda: Rhinebothriidea)

Tapeworms of the genus Anindobothrium Marques, Brooks & Lasso, 2001 are found in both marine and Neotropical freshwater stingrays of the family Potamotrygonidae. The patterns of host association within the genus support the most recent hypothesis about the history of diversification of potamotrygonids, which suggests that the ancestor of freshwater lineages of the Potamotrygonidae colonized South American river systems through marine incursion events. Despite the relevance of the genus Anindobothrium to understand the history of colonization and diversification of potamotrygonids, no additional efforts were done to better investigate the phylogenetic relationship of this taxon with other lineages of cestodes since its erection. This study is a result of recent collecting efforts to sample members of the genus in marine and freshwater potamotrygonids that enabled the most extensive documentation of the fauna of Anindobothrium parasitizing species of Styracura de Carvalho, Loboda & da Silva, Potamotrygon schroederi Fernández-Yépez, P. orbignyi (Castelnau) and P. yepezi Castex & Castello from six different countries, representing the eastern Pacific Ocean, Caribbean Sea, and river basins in South America (Rio Negro, Orinoco, and Maracaibo). The newly collected material provided additional specimens for morphological studies and molecular samples for subsequent phylogenetic analyses that allowed us to address the phylogenetic position of Anindobothrium and provide molecular and morphological evidence to recognize two additional species for the genus. The taxonomic actions that followed our analyses included the proposition of a new family, Anindobothriidae fam. n., to accommodate the genus Anindobothrium in the order Rhinebothriidea Healy, Caira, Jensen, Webster & Littlewood, 2009 and the description of two new species-one from the eastern Pacific Ocean, A. carrioni sp. n., and the other from the Caribbean Sea, A. inexpectatum sp. n. In addition, we also present a redescription of the type species of the genus, A. anacolum (Brooks, 1977) Marques, Brooks & Lasso, 2001, and of A. lisae Marques, Brooks & Lasso, 2001. Finally, we discuss the paleogeographical events mostly linked with the diversification of the genus and the protocols adopted to uncover cryptic diversity in Anindobothrium.

The morphological and behavioral analysis of geographically separated Rammeihippus turcicus (Orthoptera: Acrididae: Gomphocerinae) populations: data result in taxonomical conflict

Rammeihippus Woznessenskij, 1996 (Orthoptera: Acrididae: Gomphocerinae) is a genus represented by two species. Rammeihippus turcicus (Ramme, 1939) is the only known species of the genus from Anatolia. As for most of the Gomphocerinae species in Anatolia, all populations of the species are intermittently distributed at high altitudes. In this study, three populations of R. turcicus were studied for the first time to determine the song and mating behavior. Males of the species produce typical calling song for Gomphocerinae and complex courtship songs and mating behavior. Thus, an accurate taxonomy requires extensive material and different character sources. In this study, the Anatolian Rammeihippus was re-examined on the basis of qualitative and morphometric morphology, male songs, and behavioral characteristics. There was no agreement between the results of the song and morphology. Acoustic analysis suggested one species and patchy distribution in the area, whereas morphology pointed out that each population was a different taxonomical unit. The results of the study show that the aberrant morphology does not necessarily indicate a new species in the Gomphocerinae genus.

Cytogenetics and chromosomes of tapeworms (Platyhelminthes, Cestoda)

Tapeworms (Cestoda, Platyhelminthes) are a highly diversified group of parasites that can have significant veterinary importance as well as medical impact as disease agents of human alveococcosis, hydatidosis, taeniosis/cysticercosis/neurocysticercosis, hymenolepidosis or diphyllobothriasis. Because of their great diversity, there has been keen interest in their phylogenetic relationships to other obligate parasitic platyhelminthes, as well as within the group itself. Recent phylogenetic analyses of cestodes, however, have focused on morphological, molecular, life cycle, embryology and host-specificity features and conspicuously omitted inclusion of karyological data. Here we review the literature from 1907 to 2010 and the current status of knowledge of the chromosomes and cytogenetics within all of the cestode orders and place it within an evolutionary perspective. Karyological data are discussed and tabulated for 115 species from nine eucestode orders with ideograms of 46 species, and a comparison of cytogenetic patterns between acetabulate and bothriate cestode lineages is made. Attention is drawn to gaps in our knowledge for seven remaining orders and cestodarian groups Gyrocotylidea and Amphilinidea. Among the cytogenetic aspects covered are: chromosome number, triploidy, classical karyotype cytogenetics (banding patterns, karyotype asymmetry, secondary constrictions), as well as advanced karyotype techniques allowing location of genes on chromosomes by fluorescence in situ hybridization. We demonstrate that further progress in cestode karyosystematics rests with new molecular approaches and the application of advanced cytogenetic markers facilitating intimate karyotype analysis.

Invalidity of three Palaearctic species of Triaenophorus tapeworms (Cestoda: Pseudophyllidea): evidence from morphometric analysis of scolex hooks

A comparative study of the scolex hook morphology of five species of tapeworms of the genus Triaenophorus Rudolphi, 1793 (Cestoda: Pseudophyllidea), parasites of pikes (Esox lucius L. and E. reichertii Dybowski) in the Palaearctic Region, was carried out. Measurements of scolex hooks of 81 plerocercoids and 492 adults from different hosts and regions were compared using basic statistics and forward stepwise linear discriminant analysis. The shape of the scolex and that of tridental hooks were found to be suitable only for differentiation of the taxa with a similar shape of hooks, i.e. Triaenophorus nodulosus (Pallas, 1781) from T. amurensis Kuperman, 1968, and T. crassus Forel, 1868 from T. meridionalis Kuperman, 1968 and T. orientalis Kuperman, 1968, respectively. In contrast, discriminant analysis did not enable reliable separation of specimens of individual taxa of these two morphological groups due to high intraspecific variability and overlaps between species. This was reflected in low classification efficiencies (average 83%) of all species of the T. crassus group, whereas all T. amurensis specimens were misidentified as T. nodulosus. The new data also considerably enlarge (up to twofold) the size range of the species described by Kuperman in 1968, which invalidates suitability of the most important discriminant characteristic, the width of the basal plate, for delimitation of Triaenophorus species. Based on the present data, all Kuperman's taxa are considered to represent only distinct geographical populations of T. nodulosus and T. crassus. As a result, T. anmurensis is synonymized with T. nodulosus, whereas T. orientalis is considered to be a synonym of T. crassus. Previous synonymisation of T. ineridionalis with T. crassus, first proposed by Dubinina (1987), is also accepted.

Cryptic species of Didymobothrium rudolphii (Cestoda: Spathebothriidea) from the sand sole, Solea lascaris, off the Portuguese coast, with an analysis of their molecules, morphology, ultrastructure and phylogeny

Didymobothrium rudolphii (Cestoda: Spathebothriidea) was collected seasonally from the sand sole, Solea lascaris, off the northern, central and southern areas of the Portuguese coast. Morphological and molecular analyses were conducted in order to examine the possible existence of cryptic species and to facilitate the circumscription of their morphological boundaries. Data were compared between D. rudolphii specimens from each of the 3 geographical areas and 4 seasons, and principal components analysis of 18 morphological characters was used to detect differences. Two distinct genotypes were present with sequence divergences of 1.9% and 2.1% in the large subunit (lsrDNA) and second internal transcribed spacer (ITS-2) of ribosomal DNA (rDNA), respectively. The less common 'central' genotype was present only off the central area from summer to winter, whereas the 'common' genotype was present throughout the year off the northern and southern areas, but only during spring in the central area. No sequence variation was found within each genotype. The presence of 2 distinct genetic entities was supported by morphological analyses, which showed the 'central' genotype specimens to be more slender and elongate, although morphometric ranges overlapped considerably for most characters. Molecular phylogenetic analysis of 4 of the 5 known genera of the Spathebothriidea showed Spathebothrium to be the earliest branching lineage and the 2 genotypes of Didymobothrium formed a sister group to Cyathocephalus. The concordance of genetic differences with variation in host diet according to season and locality could account for sympatric speciation occurring in the central region of the Portuguese coast.

Redescription of Eubothrium fragile (Rudolphi, 1802) and E. rugosum (Batsch, 1786) (Cestoda: Pseudophyllidea), parasites of fish in the Holarctic Region

Two fish cestodes, the little-known Eubothrium fragile (Rudolphi, 1802) and E. rugosum (Batsch, 1786), the type species of the genus Eubothrium Nybelin, 1922, are redescribed on the basis of new material from twaite shad, Alosa fallax (Lacépède, 1803), from England and burbot, Lota lota (Linnaeus, 1758), from Russia, respectively. The tapeworms are compared with two other species of the genus, E. crassum (Bloch, 1779) and E. salvelini (Schrank, 1790), common parasites of salmonid fish in the Holarctic. The most notable differential characters are the size and the shape of the scolex (smaller and oval in E. fragile), the shape of the apical disc (four or more indentations in E. crassum), the number and size of the testes (the largest and least numerous in E. rugosum), and the position and size of the vitelline follicles (almost entirely cortical in distribution in E. fragile and E. crassum versus largely medullary in E. rugosum and E. salvelini). A comparison of species has also shown the morphological similarity of the freshwater species (E. rugosum and E. salvelini) on one hand and those of marine origin, E. fragile and E. crassum, on the other, with the latter species occurring also in fresh waters. A key to the identification of the species studied is also provided.