Three new enchytraeid species (Enchytraeidae, Annelida) from mountain soils of Korea and ten species new for the country.

In this paper, three new enchytraeid species (Enchytraeidae, Clitellata) are described from different mountains of Korea: Cognettia koreana sp. n., Henlea bidiverticulata sp. n. and Mesenchytraeus longidiverticulatus sp. n. Validity of these new species was confirmed by comparative morphological and molecular taxonomic analyses (based on ITS, CO1 and H3 sequences). In addition, ten enchytraeid species never recorded before from Korea were found in the studied soil samples: Bryodrilus diverticulatus Cernosvitov, 1929, Cernosvitoviella atrata Bretscher, 1903, Cernosvitoviella minor Dózsa-Farkas, 1990, Cognettia lapponica Nurminen, 1965, Cognettia varisetosa (Martinsson, Rota Erséus, 2015), Fridericia cf. sohlenii Rota, Healy Erséus, 1998, Henlea nasuta Eisen, 1878, Marionina clavata Nielsen Christensen, 1961, Marionina communis Nielsen Christensen, 1959, Marionina seminuda Xie Rota, 2001. Morphological observations and new reference DNA sequences are also provided for the above-mentioned species.

Two new enchytraeid species from Jeju Island, Korea (Annelida, Clitellata).

The enchytraeid fauna of three areas in Jeju Island (Korea) was studied, and comparative morphological and molecular taxonomic examinations (based on CO1, ITS and H3 sequences) were performed on nine samples collected in 2016. Twenty-two enchytraeid species were recorded and identified. The descriptions of two new species (Achaetamultisacculata sp. n. and Fridericiafloriformis sp. n.) are presented in this paper. The main diagnostic features of A.multisacculata sp. n. are: three pairs of pyriform glands per segment, clitellum with two "baguette-like" packages of glands, dorsal blood vessel from VII, secondary pharyngeal glands absent, oesophageal appendages well developed, two pairs of preclitellar nephridia, the reproductive organs (except the spermathecae in V) shifted one segment forward. The main features of F.floriformis sp. n. are that they are large worms, have up to 2-4 chaetae in bundles, strong body wall, thick cuticle, five pairs of preclitellar nephridia, c-type coelomo-mucocytes sometimes with some refractile vesicles, chylus cells in XII-XV, sperm funnels approximately twice as long than wide, spermathecae with long ectal duct without glands, ampullae surrounded distally by about 9-12 sessile diverticula of varying size. Molecular phylogenetic analyses supported the morphological results and confirmed the status of the two new species.

Decimodrilus, a new enchytraeid genus from Korea (Annelida, Clitellata, Enchytraeidae).

Two new species of the new genus Decimodrilus gen. n. are described in this paper from oak forests of South Korea using a combination of classical morphology and DNA-based molecular taxonomy. A characteristic trait of the new genus is the occurrence of the intestinal diverticula in segments IX-X. The main morphological features of the new genus are: 4-5(6) straight chaetae per bundle, origin of dorsal vessel in clitellar region, anteseptale of nephridia consisting of funnel only, coelomocytes only mucocytes, oesophageal appendages absent, spermathecae united proximally and connected jointly with the oesophagus. Decimodrilus diverticulatus sp. n. has spermathecae with two diverticula-like protrusions and two globular sperm masses. D. globulatus sp. n. has spermathecae with two or three sperm rolls. Molecular taxonomic analysis based on a concatenated phylogenetic tree supports the status of the new genus and that of the two new species.

Morphological and molecular distinction of two Fridericia species (Clitellata, Enchytraeidae) having same spermatheca type.

One enchytraeid species, proved to be new to science, is described in this paper as Fridericia ventrochaetosa sp. nov. The new species is distinguished from similar species, especially from F. galba (Hoffmeister, 1843), which has almost the same type of spermatheca, on the basis of morphological characters and molecular data (nuclear ribosomal ITS region, mitochondrial cytochrome c oxidase subunit I and nuclear histone 3 gene sequences). Apart form the new species, GenBank reference sequences are provided for the first time for F. hegemon and F. regularis. The results show that, although the shape of the spermatheca is a very important marker in the case of Fridericia species, other characters can be equally important for their taxonomic identification.

New enchytraeid species from Mount Hallasan (Jeju Island, Korea) (Enchytraeidae, Oligochaeta).

The enchytraeid fauna of Mt. Hallasan (Jeju Island, Korea) was studied in 2016, and 21 enchytraeid species were recorded and identified in total. A combination of morphological and molecular analyses (based on CO1, ITS and H3 sequences) was applied. Here we give descriptions of eight new species of Enchytraeidae (Clitellata): Achaeta koreana sp. n., Achaeta macroampullacea sp. n., Bryodrilus hallasanensis sp. n., Chamaedrilus baekrokdamensis sp. n., Enchytronia seongpanakiensis sp. n., Mesenchytraeus jungsaihoi sp. n., Xetadrilus jejuensis sp. n. and Xetadrilus aphanoides sp. n. Additionally, two species were found to be new for the Korean fauna in Mt. Hallasan: Fridericia cf. paroniana Issel, 1904 and F. perrieri (Vejdovský, 1878); three potentially new Fridericia species require further studies. Furthermore, two terrestrial polychaetes, Hrabeiella periglandulata Pizl Chalupský, 1984 and Parergodrilus heideri Resisinger, 1925, were recorded. For 12 enchytraeid species, DNA sequences are presented for the first time: these include, apart from the new species, further taxa such as species of Xetadrilus, a genus of which no sequences were previously available.

A new Cernosvitoviella species (Clitellata: Enchytraeidae) and its comparison with other Cernosvitoviella species from Sphagnum mires in Hungary.

Results of a comparative investigation on five Cernosvitoviella species from Hungarian Sphagnum mires including their distribution and the description of a new species, Cernosvitoviella farkasi sp. n., are presented in this paper. Cernosvitoviella atrata, C. aggtelekiensis, C. crassoductus and C. farkasi sp. n. could be easily distinguished from each other based on both morphological and molecular taxonomic analyses. However, C. minor seems to be a species complex on the basis of these investigations, so it was referred as C. minor sensu lato. The status of the C. minor variants requires further studies.

Comparative morphological and molecular taxonomic study of six Achaeta species (Clitellata: Enchytraeidae) with the description of a new Achaeta species from Koszeg Mountains, Hungary.

Five Achaeta species (A. affinis, A. bohemica sensu stricto, A. camerani, A. cf. danica, A. unibulba) and a new species, described here as A. tothi sp. n., were found during the investigation of the enchytraeid fauna of western Hungary (Orség National Park and Koszeg Mts.). Comparative morphological and molecular taxonomic investigations were performed with several individuals representing these six Achaeta species. A detailed description of the new species is given, and we also present some additional morphological data and photos about the other five Achaeta species. Such information could have importance in subsequent taxonomic studies and will aid the discrimination among the members of genus Achaeta. Furthermore, the obtained sequences could serve as references in forthcoming studies applying DNA-based taxon identification.

Unexpected occurrence of Hemifridericia bivesiculata Christensen & Dózsa-Farkas, 2006 in Hungary, a species presumed to be endemic to Devon Island, Canada, and its comparative analysis with H. parva Nielsen & Christensen, 1959 (Enchytraeidae, Oligochaeta).

During the exploration of the enchytraeid fauna in forests and grasslands of Hungarian flat areas, a small enchytraeid species, Hemifridericia bivesiculata Christensen & Dózsa-Farkas, 2006, was found unexpectedly. This species was known previously only from one single location, Bank Island in the Canadian archipelago, and was presumed to be endemic. Here, the distinctive features of the two Hemifridericia species are described based on detailed morphological analyses, which were supported with molecular methods. The results demonstrated that the two Hemifridericia species are very similar morphologically, but can be clearly distinguished from each other by the presence or absence of the oesophageal vesicles and the shape of the brain. Some additional differences were observed between the Hungarian material and the type specimens of H. bivesiculata. The two species were unequivocally separated based on the studied molecular markers, the mitochondrial cytochrome c oxidase subunit I (CO1) gene, the nuclear histon 3 (H3) gene and the nuclear ribosomal ITS region. 

Three new Fridericia species (Oligochaeta, Enchytraeidae) from Transylvania, Romania.

We give descriptions of three new Fridericia species (Enchytraeidae, Oligochaeta) from Transylvania, Romania. Fridericia transylvanica sp. n. is a large-sized worm with a maximum of 4 chaetae per bundle. The spermathecae are separate entally and have two sac-like diverticula bent distad with the ampulla forming a common U-shaped sperm-containing chamber. The species was found not only in the Transylvanian Plateau but also in different regions of the Carpathians in Romania and Serbia. Fridericia gyromonodactyla sp. n. is medium-sized with a maximum of 3 chaetae per bundle. There are only four pairs of preclitellar nephridia. The spermathecal ectal duct is contractile and shorter than the body diameter; each ampulla has only one diverticulum, elongate and coiled, and there is one sessile gland at the orifice. Fridericia longeaurita sp.n. is large-sized with 4(5) chaetae per preclitellar bundle but only two or one in postclitellar bundles. The spermathecal ectal duct is shorter than the body diameter, with one small and sessile ectal gland at the orifice. Each ampulla has two long, ear-shaped, and sac-like diverticula. None of the three species were rare at the sites where they occurred. 

New enchytraeid species (Enchytraeidae, Oligochaeta) from Korea.

We give descriptions of five new enchytraeid species (Enchytraeidae, Oligochaeta) from Korea: Henlea magnaampullacea sp. n., Fridericia sphaerica sp. n., F. cusanicaformis sp. n., F. granulocyta sp. n. and Mesenchytraeus calyx sp. n., with morphological and molecular (mitochondrial cytochrome c oxidase subunit I, nuclear histone 3 genes and nuclear ribosomal ITS region sequences) data. In total, 19 enchytraeid species belonging to seven genera have been found in the studied woodland and agronomical soil samples. Apart from the five new species, three further species are new for the Korean enchytraeid fauna, Enchytraeus christenseni, E. dichaetus, and Achaeta cf. brevivasa. Molecular taxonomical analyses show that the Korean species resembling H. ventriculosa is not identical with the European species, furthermore sequence analysis of individuals morphologically identified as F. seoraksani indicate the possibility of species-complexity and the presence of cryptic species.