Global species delimitation of the cosmopolitan marine littoral earthworm Pontodrilus litoralis (Grube, 1855).

The marine littoral earthworm Pontodrilus litoralis (Grube, 1855) is widely distributed and is reported as a single species. This study utilized an integrative taxonomic approach based upon morphological examination, phylogenetic reconstruction, and molecular species delimitation, to test whether the taxon is a single species or a species complex. For this, a total of 114 P. litoralis specimens collected from North America, Africa, Australia and Oceania, Europe and Asia were used. The phylogenetic analyses revealed deeply divergent mitochondrial lineages and a high level of genetic diversity among P. litoralis populations. Both single and multi-locus species delimitation analyses yielded several molecular operational taxonomic units. Therefore, due to the homogeneity of morphological characteristics, it is likely that the morphospecies P. litoralis is a complex of four or more cryptic species, suggesting that more sampling is required and that the population structure genetic data and gene flow need to be investigated.

Cryptic carnivores: Intercontinental sampling reveals extensive novel diversity in a genus of freshwater annelids.

Freshwater annelids are globally widespread in aquatic ecosystems, but their diversity is severely underestimated. Obvious morphological features to define taxa are sparse, and molecular phylogenetic analyses regularly discover cryptic diversity within taxa. Despite considerable phylogenetic work on certain clades, many groups of freshwater annelids remain poorly understood. Included among these are water nymph worms of the genus Chaetogaster (Clitellata: Tubificida: Naididae: Naidinae). These worms have diverged from the detritivorous diet of most oligochaetes to become more predatory and exist as omnivores, generalist predators, parasites, or symbionts on other invertebrates. Despite their unusual trophic ecology, the true diversity of Chaetogaster and the phylogenetic relationships within the genus are uncertain. Only three species are commonly referenced in the literature (Chaetogaster diaphanus, Chaetogaster limnaei, and Chaetogaster diastrophus), but additional species have been described and prior molecular data suggests that there is cryptic diversity within named species. To clarify the phylogenetic diversity of Chaetogaster, we generated the first molecular phylogeny of the genus using mitochondrial and nuclear sequence data from 128 worms collected primarily across North America and Europe. Our phylogenetic analyses suggest that the three commonly referenced species are a complex of 24 mostly cryptic species. In our dataset, Chaetogaster "diaphanus" is represented by two species, C. "limnaei" is represented by three species, and C. "diastrophus" is represented by 19 species. North American and European sequences are largely interspersed across the phylogeny, with four pairs of clades involving distinct North American and European sister groupings. Overall, our study demonstrates that the species diversity of Chaetogaster has been underestimated and that carnivory has evolved at least twice in the genus. Chaetogaster is being used as a model for symbiotic evolution and the loss of regenerative ability, and our study indicates that researchers must be careful to identify which species of Chaetogaster they are working with in future studies.

Testing species hypotheses for Fridericia magna, an enchytraeid worm (Annelida: Clitellata) with great mitochondrial variation.

BACKGROUND: Deep mitochondrial divergences were observed in Scandinavian populations of the terrestrial to semi-aquatic annelid Fridericia magna (Clitellata: Enchytraeidae). This raised the need for testing whether the taxon is a single species or a complex of cryptic species. RESULTS: A total of 62 specimens from 38 localities were included in the study, 44 of which were used for species delimitation. First, the 44 specimens were divided into clusters using ABGD (Automatic Barcode Gap Discovery) on two datasets, consisting of sequences of the mitochondrial markers COI and 16S. For each dataset, the worms were divided into six not completely congruent clusters. When they were combined, a maximum of seven clusters, or species hypotheses, were obtained, and the seven clusters were used as input in downstream analyses. We tested these hypotheses by constructing haplowebs for two nuclear markers, H3 and ITS, and in both haplowebs the specimens appeared as a single species. Multi-locus species delimitation analyses performed with the Bayesian BPP program also mainly supported a single species. Furthermore, no apparent morphological differences were found between the clusters. Two of the clusters were partially separated from each other and the other clusters, but not strongly enough to consider them as separate species. All 62 specimens were used to visualise the Scandinavian distribution, of the species, and to compare with published COI data from other Fridericia species. CONCLUSION: We show that the morphospecies Fridericia magna is a single species, harbouring several distinct mitochondrial clusters. There is partial genetic separation between some of them, which may be interpreted as incipient speciation. The study shows the importance of rigorous species delimitation using several independent markers when deep mitochondrial divergences might give the false impression of cryptic speciation.

A new Scandinavian Chamaedrilus species (Clitellata: Enchytraeidae), with additional notes on others.

Chamaedrilus (earlier referred to as Cognettia) is a well-known genus of terrestrial and limnic enchytraeids, currently with 19 known species in the world. Some of its species are morphologically cryptic and can only be identified using genetic (DNA) information. Many of them reproduce asexually, and the prevalence of sexual mature individuals is generally low in the populations. Chamaedrilus asloae sp. nov. (Clitellata: Enchytraeidae) is described based on material from two rivers in Norway, one in Sweden, and from a wet deciduous forest in Denmark. With the material at hand, no morphological characters completely separate C. asloae from C. chalupskyi; none of the available specimens of the new species are sexually mature. However, four molecular markers (two mitochondrial, two nuclear) support that C. asloae is a distinct, separately evolved lineage, which is sister to a clade consisting of C. glandulosus and C. varisetosus. In this study, too, the fully developed sexual organs of C. chalupskyi and C. varisetosus are described and illustrated.

Green light to an integrative view of Microscolex phosphoreus (Dugès, 1837) (Annelida: Clitellata: Acanthodrilidae).

The small synanthropic and peregrine earthworm Microscolex phosphoreus (Dugès, 1837) is reported for the first time from Siberia. Morphological and DNA barcode (COI) analyses of this and widely separate samples worldwide demonstrate that, as currently identified, M. phosphoreus is a heterogeneous taxon, with divergent lineages occurring often in the same locality and hardly providing geographically structured genetic signals. The combined morphological and genetic evidence suggests that at least four of the found clades should be reclassified as separate species, both morphologically and genetically distinct from each other. However, as the specimen number was limited and only the COI gene was studied for the genetic work, we hesitate in formally describing new species. There would also be the problem of assigning the available names to specific lineages. Our findings encourage careful external and anatomical examination and using reliable characters such as the interchaetal distances and spermathecal morphology for correct identification and for deeper evaluation of cryptic diversity in this interesting bioluminescent worm.

Multi-locus phylogenetic analysis of the genus Limnodrilus (Annelida: Clitellata: Naididae).

Limnodrilus species are annelid worms distributed worldwide in various freshwater sediments. The systematics of Limnodrilus has chiefly been based on morphology, but the genus has not been subject to any closer phylogenetic studies over the past two decades. To reconstruct the evolutionary history of Limnodrilus, and to assess the monophyly of this genus and its systematic position within the subfamily Tubificinae (Annelida: Clitellata: Naididae), 45 Limnodrilus specimens, representing 19 species, and 35 other naidid species (representing 24 genera) were sampled. The data consisted of sequences of three mitochondrial genes (COI, 12S and 16S rDNA) and four nuclear markers (18S and 28S rDNA, Histone 3, and ITS). The phylogeny was estimated, using Maximum Likelihood and Bayesian analyses of concatenated data of seven DNA loci, as well as a multi-locus coalescent-based approach. All analyses strongly suggest that Limnodrilus is monophyletic, but only if the morphospecies L. rubripenis is removed from it. Limnodrilus rubripenis and (at least) Baltidrilus, Lophochaeta and some species attributed to Varichaetadrilus comprise the sister group to the clade Limnodrilus sensu stricto, and the latter is further divided into three well-supported groups. One of them contains morphospecies characterized by short cuticular penis sheaths and enlarged chaetae in anterior segments (L. udekemianus, L. silvani and L. grandisetosus). The second is a small group of species with moderately long penis sheaths, i.e., L. sulphurensis and L. profundicola. The third, and largest group, includes not only the multitude of cryptic species in the L. hoffmeisteri complex, but also other, morphologically distinct, species nested within this complex. All studied species in this large group have long penis sheaths, which are exceptionally long in L. claparedianus, L. maumeensis, and a form morphologically intermediate between L. claparedianus and L. cervix. The identification and classification of these groups provide a framework for directed sampling in further phylogenetic studies, and for revisionary work on the L. hoffmeisteri complex and other unresolved Limnodrilus species.

Cryptic speciation and limited hybridization within Lumbricus earthworms (Clitellata: Lumbricidae).

Cryptic mitochondrial (mt) lineages are known to exist in the earthworm morphospecies Lumbricus rubellus and L. terrestris. The latter was recently split into two species, L. terrestris and L. herculeus, based on large genetic distances and a statistical difference in body size. There is support for the separation of some lineages in L. rubellus into species, whereas other lineages, separated by similar mt genetic distances, have been found to be part of the same species. However, no study has evaluated the status of the cryptic mt lineages in L. terrestris-L. herculeus and L. rubellus using nuclear genes. We use a combination of methods to reveal extensive cryptic speciation and limited hybridization in Lumbricus, based on one nuclear (H3) and one mitochondrial (COI) marker. Using a Bayesian multi-locus species delimitation method, as well as single gene haplotype networks and gene trees, we delimit seven well supported cryptic species within the morphospecies L. rubellus, and confirm the split within the species-pair L. terrestris-L. herculeus. Limited hybridization was found between the most common species of L. rubellus (A) in northern Europe and two other species (B and H) in this complex, as well as between L. terrestris and L. herculeus. Deep mt divergence was found within L. terrestris s.str. but no support for further splitting of this taxon was found. Both L. rubellus and L. terrestris are well studied model organisms, and considering that cryptic species and hybridization were found within them, it is important that they are properly identified in future studies.

Barcoding gap, but no support for cryptic speciation in the earthworm Aporrectodea longa (Clitellata: Lumbricidae).

DNA-barcoding, using the mitochondrial marker COI, has been found successful for the identification of specimens in many animal groups, but may not be suited for species discovery and delimitation if used alone. In this study, we investigate whether two observed COI haplogroups in the earthworm Aporrectodea longa correspond to two cryptic species or if the variation is intraspecific. This is done by complementing COI with two nuclear markers, ITS2 and Histone 3. The variation is studied using distance methods, parsimony networks and Bayesian coalescent trees, and the statistical distinctness of the groups is tested on gene trees using the genealogical sorting index, Rosenberg's PAB and Rodrigo et al.'s P(RD). We also applied multilocus species delimitation based on the multispecies coalescence model. The two haplogroups were found in COI, and all tests except P(RD) found them to be significantly distinct. However, in ITS2, the same groups were not recovered in any analyses or tests. H3 was invariable in A. longa, and was, therefore, included only in the multilocus analysis, which preferred a model treating A. longa as one species over a model splitting it into two. We also compared two measurements of size, body length, and no. of segments between the groups. No difference in body length was found, and although a significant difference in no. of segments was noted the haplogroup with the lower mean showed both the highest and the lowest value. When combined, these results led us to the conclusion that there is no support for the separation of A. longa into two cryptic species. This study again highlights the importance of complementing mitochondrial barcodes with more data when establishing species boundaries.

On the identity of Chamaedrilusglandulosus (Michaelsen, 1888) (Clitellata, Enchytraeidae), with the description of a new species.

The taxonomy of Chamaedrilusglandulosus (Michaelsen, 1888) s. l., most commonly known previously as Cognettiaglandulosa, is revised. A recent molecular systematic study has shown that this taxon harbours two cryptic, but genetically well separated lineages, each warranting species status. In this study these two lineages are scrutinized morphologically, on the basis of Michaelsen's type material as well as newly collected specimens from Central and Northern Europe. Chamaedrilusglandulosus s. s. is redescribed and Chamaedrilusvarisetosus sp. n. is recognized as new to science. The two species are morphologically very similar, differing mainly in size, but seem to prefer different habitats, with Chamaedrilusglandulosus being a larger aquatic species, and Chamaedrilusvarisetosus being smaller and mainly found in moist to wet soil.

Corrigenda: Martinsson S, Rota E, Erséus C (2015) On the identity of Chamaedrilusglandulosus (Michaelsen, 1888) (Clitellata, Enchytraeidae), with the description of a new species. ZooKeys 501: 1-14. doi: 10.3897/zookeys.501.9279.

[This corrects the article DOI: 10.3897/zookeys.501.9279.].

Ancistrocerus waldenii waldenii (Viereck 1906) (Hymenoptera: Vespidae, Eumeninae), a new addition to the fauna of Greenland.

Ancistrocerus waldenii waldenii (Viereck 1906) is newly recorded from West Greenland. This is a new northern limit for the species.

Oligochaeta (Annelida) of the profundal of Lake Hazar (Turkey), with description of Potamothrix alatus hazaricus n. ssp..

Lake Hazar is an alkaline oligotrophic lake of tectonic origin, located in the Eastern Anatolia region in Turkey, 1248 a a.s.l. Its surface area is 80 km2, the average depth 93 m and maximum depth 205 m. The lake and its surroundings an under protection as a region of historical value. During the present study (2007-2012), samples were taken from 15 stations located at a depth of 2-200 m. Oligochaeta comprised 69% of the total invertebrate abundance. The profundal olgochaete fauna was found to consist of only three tubificid taxa, all of the subfamily Tubificinae. Potamothrix alatus hazaricus Timm & Arslan, n. ssp. was dominating anywhere down to maximum depths while Psammoryctides barbatus (Grube) and Ilyodrilus(?) sp. occurred seldom. All three are new records for Lake Hazar. Potamothrix alatus hazaricus shares the "winged" body shape in its genital region with the nominal, brackish-water subspecies P. a. alatus Finogenova, 1972, and the lateral position of the spermathecal pores and the shape of the ventral chaetae with the freshwater subspecies P. a. paravanicus Poddubnaja & Pataridze, 1989 known from Transcaucasian lakes. The mitochondrial COI barcoding gene suggests long separation between the two taxa, but the nuclear ITS region shows no variation. The generic position of Ilyodrilus (?) sp. remains obscure since its internal genitalia could not be studied.

Katatopygia gen. n., a monophyletic branch segregated from Boletina (Diptera, Mycetophilidae).

The genus Katatopygiagen. n. is proposed for the Boletina erythropyga/punctus-group that was first introduced by Garrett (1924, 1925) and currently comprises eight described species. Molecular studies have strongly indicated that this group forms a monophyletic sister-group to a clade consisting of all other Boletina, Coelosia and Gnoriste, and its monophyly is supported by morphological data as well. The new genus includes the following species: Katatopygia antoma (Garrett, 1924), comb. n., Katatopygia antica (Garrett, 1924), comb. n., Katatopygia erythropyga (Holmgren, 1883), comb. n.,Katatopygia hissarica (Zaitzev & Polevoi, 2002), comb. n., Katatopygia magna (Garrett, 1925), comb. n., Katatopygia laticauda (Saigusa, 1968), comb. n., Katatopygia neoerythropyga (Zaitzev & Polevoi, 2002), comb. n. andKatatopygia sahlbergi (Lundström, 1906), comb. n., all transferred from Boletina. Katatopygia sahlbergi is found to be a senior synonym of Boletina punctus Garrett, 1925, syn. n. A phylogeny based on morphological data and using parsimony analysis yielded four most parsimonious trees where the new genus is retrieved as monophyletic with high support. Katatopygia neoerythropyga is found to be the sister-taxon to all other species that form two clades, one with Katatopygia sahlbergi-like species and one with Katatopygia erythropyga-like species. A key to males of Katatopygia is provided.