Protistology

We review the species of Difflugia with shells that are spherical or ovoid, based primarily on examinations of two collections in the Natural History Museum, London, UK: (i) Penard’s collection of balsam-mounted microscope slides, and; (ii) Ogden’s scanning electron micrographs and shell measurements. We discuss testate amoebae taxa grouped into seven species complexes, namely Difflugia globulosa Dujardin, 1837, Difflugia rotunda (Chardez, 1956) Ogden,1983, Difflugia minuta Rampi, 1950, Difflugia viscidula Penard, 1902, Difflugia pulex Penard, 1902, Difflugia glans Penard, 1902, and Difflugia molesta Penard, 1902. Within the D. globulosa-complex we: (i) distinguish as a separate taxon D. globulosa Dujardin, 1837, and (ii) synonymise D. chardezi Godeanu, 1972 with D. globulosa Dujardin, 1837. Within the D. rotunda-complex we: (i) distinguish as separate taxa D. rotunda (Chardez, 1956) Ogden, 1983, and D. lebes Penard, 1902; (ii) synonymise D. lebes var. sphaerica Gauthier-Lièvre et Thomas, 1958 with D. lebes Penard, 1902, and D. lebes var. masurica Schönborn, 1965 and D. lebes var. bretschkoi Laminger, 1971 with D. viscidula Penard, 1902. Within the D. minuta-complex we: (i) distinguish as a separate taxa D. minuta Rampi, 1950, D. angulostoma Gautier-Lièvre et Thomas, 1958, and D. geosphaira Ogden, 1991; (ii) synonymise D. minuta var. grandis Gautier-Lièvre et Thomas, 1958 with D. difficilis Thomas, 1954, and D. minuta var. minor Godeanu, 1972 with D. pulex Penard, 1902; and (iii) discuss the validity of D. dujardini Chardez, 1957. Within the D. viscidula-complex we: (i) distinguish as a separate taxon D. viscidula Penard, 1902; and (ii) synonymise D. lemani Blanc, 1892, D. histrio Penard, 1908, D. finstertaliensis Laminger, 1971, D. lebes var. masurica Schönborn, 1965, and D. lebes var. bretschkoi Laminger, 1971 with D. viscidula Penard, 1902. Within the D. pulex-complex we: (i) distinguish as separate taxa D. pulex Penard, 1902, D. pristis Penard, 1902, and D. mica Frentzel, 1892; (ii) synonymise D. ovalisina Beyens et Chardez, 1994 and D. minuta var. minor Godeanu, 1972 with D. pulex Penard, 1902, and (iii) discuss the validity of D. richmondiae Playfair, 1914, D. stechlinensis Schönborn, 1962, and D. humilis Chardez, 1991. Within the D. glans-complex we: (i) distinguish as separate taxa D. glans Penard, 1902, D. ampullula Playfair, 1918, and D. penardi (Penard, 1890) Hopkinson, 1909; (ii) synonymise D. manicata Penard, 1902 and D. tenuis (Penard, 1890) Ogden, 1983 with D. penardi (Penard, 1890) Hopkinson, 1909, and (iii) discuss the validity of D. masaruzii van Oye, 1958 and D. decloitrei Godeanu, 1972. Within the D. molesta-complex we: (i) distinguish as separate taxa D. molesta Penard, 1902, D. brevicolla Cash et Hopkinson, 1909, and D. difficilis Thomas, 1954; (ii) synonymise D. pyriformis var. atricolor Penard, 1902 with D. brevicolla Cash et Hopkinson, 1909; D. difficilis var. ecornis Chardez, 1956, D. microstoma (Thomas, 1954) Ogden, 1983, and D. minuta var. grandis Gauthier-Lièvre et Thomas, 1958 with D. difficilis Thomas, 1954; D. levanderi Playfair, 1918 with D. molesta Penard, 1902. As in the first two parts of this series of papers, we conclude that, based on current knowledge, it is unclear whether these species complexes represent single, highlypolymorphic species, or groups of sibling species. Further studies based on acombination of morphometric, scanning electron microscopic, molecular, and environmental data are needed in order to characterize these species complexes in more detail and thus resolve their systematics.

In this paper we report the diversity of metchnikovellids discovered in two surveys at the silt littoral/sublittoral zone in vicinity of Marine Biological Station of St. Petersburg State University, Island Sredniy, Chupa Inlet, Kandalaksha Gulf of the White Sea performed in 1986-1987 and in 2009-2011. The list of metchnikovellid species that had been recorded for the locality includes: Metchnikovella hovassei, a parasite of the gregarine Lecudina sp. from the polychaete Allita (Nereis) virens; M. selenidii, a parasite of Selenidium sp. from Ophelia limacina; M. spiralis and M. incurvata from Polyrhabdina sp. from Pygospio elegans; and Amphiamblys capitellae from Ancora sagittata from Capitella capitata. Noteworthy, M. incurvata was never observed in the 1986-1987 survey. In 2009-2011 though, it became even more abundant than M. spiralis. Given the patchy distribution of metchnikovellids among gregarine and polychaete populations, M.incurvata might have been overlooked in 1986-1987 survey. Alternatively, the emergence of M. incurvata in the White Sea polychaetes can be the result of spreading of North Atlantic populations of Pygospio elegans species complex infected with M. incurvata, to the North and mixing them with local M. incurvata-free but M. spiralis-infected populations. Such tendency of expanding ranges for certain species presumably due to global warming and/or anthropogenic factors has been recently shown for several free living and parasitic organisms including microsporidia.

Ключевые слова

.