Preliminary report on the Enchytraeidae (Oligochaeta) of West Florida

A wide range of habitats, both terrestrial and marine littoral, were sampled in an area between Pensacola and Tallahassee. Enchytraeids were present in all moist or wet soils and in marine habitats enriched by organic matter but were absent or rare in very dry soils, saturated or flooded substrates and clean intertidal sand. Between 70 and 75 species were distinguished of which 50–55 are new to North America and about 25 are probably new to science. The genera represented are the same as those occurring in Western Europe but their relative importance differs and there are some tropical elements. The number of species occurring in terrestrial sites was greater than recorded in similar surveys in southwestern France and Ireland (approximately the same-sized area, number of sites and size of sample), but the number of species per sample was lower than in either of the other countries. It is concluded that species distribution in western Florida is very patchy. Possible reasons for this patchiness are discussed.     

Specific criteria in Grania (Oligochaeta,Enchytraeidae)

The structure of the penial bulb and male efferent duct system of Grania species may be used in addition to setal pattern and spermathecal shape to distinguish species. Six penial bulb types are distinguished: (1) a simple, small, glandular bulb surrounding the male pore; (2) a small, glandular bulb, with a large, associated, dorso-medial gland mass; (3) a small glandular bulb, medial to the male pore, with an elongate male bursa (the aglandular sac), the vas deferens exitting directly into the invaginated male pore; (4) a glandular bulb with an aglandular sac and a small, cuticular stylet embedded in the bulb, extending from the ectal end of the vas deferens; (5) a glandular bulb and an aglandular sac with a long stylet extending from the vas deferens, through the bulb into the sac; and (6) glandular bulb reduced or absent, with or without an aglandular sac; with a long stylet and other prominent modifications, usually muscular, of the vas deferens. The details of the male duct structure were consistent within specimens grouped on the basis of setal distribution and shape and detailed spermathecal structure. Diverse male duct patterns are found within the polytypic species G. macrochaeta and G. postclitellochaeta. The positions of the spermathecal and male pores in their respective segments are distinctive for some species.     

Preliminary investigations of hybridization/reticulate evolution in Guaranidrilus (Enchytraeidae: Oligochaeta)

The identification of gut diverticula at 7/8 as a synapomorphy and recognition of all taxa of Guaranidrilus has been obscured by losses of gut diverticula within the lineage. The homoplastic occurrence of basally unpaired peptonephridia in some enchytraeid species has similarly obscured the limits of Hemienchytraeus. Taxa with unpredictable relationships, morphogenic irregularities in some reproductive structures, and, apparently, modified modes of reproduction, suggest the possibilities of hybridization between taxa with both close and distant relationships.     

The occurrence of species of semi-aquatic Enchytraeidae (Oligochaeta) in Ireland

The Enchytraeidae are essentially terrestrial oligochaetes but many species have marked aquatic tendencies. Over two thirds of recorded Irish species were found in soils which were submerged or frequently flooded and 35% showed a distinct preference for these conditions. Relatively few species were living in soils subject to drought. Red blood was present in 28 species, all but one from soils with more than 55% water. Cognettia sphagnetorum and C. glandulosa developed red blood in very wet conditions. In a survey of Irish wetlands, samples were taken from bog, heath, marsh, fen, margins of lakes and rivers, and saltmarsh. The influence of various environmental parameters was determined using ordination techniques. Magnesium and pH were found to be the most important factors. A high level of magnesium distinguished coastal sites and pH 5.2 separated two clusters representing acid peat and marsh-fen-aquatic sites. Groups of indicator species characterized each of the three clusters. The ecological distribution of the indicator species is described, and their usefulness in classifying enchytraeid communities is discussed.     

Molecular phylogeny of Enchytraeidae (Oligochaeta) indicates separate invasions of the terrestrial environment

Enchytraeidae is a family of soil inhabiting small‐ to medium‐sized oligochaete worms using degradable plant material as a food source and primarily adapted to terrestrial or semi‐terrestrial environments. The molecular phylogeny based upon both mitochondrial and nuclear genes indicates early segregations of the two genera Enchytraeus and Lumbricillus leaving the remaining genera included in this study as a later segregated major monophyletic branch. Extant members of the two former genera dominate in decaying seaweed in the littoral zone along the sea although members of in particular the genus Enchytraeus have also invaded other habitats. Historically the littoral zone of the sea is undoubtedly the first terrestrial or semi‐terrestrial habitat where dead plant material accumulates to any greater extent and Enchytraeus and Lumbricillus may represent early successful attempts to exploit this resource. Inland soils probably had to await the emergence of land plants in order to provide a similar food resource and here the major branch of enchytraeid genera diversified into a high number of species in the numerous decomposer networks of this varied environment. A subdivision into the genera Enchytraeus and Lumbricillus on the one hand and a branch of mainly inland genera on the other is supported by differences in two somewhat neglected morphological features. Firstly, in Enchytraeus and Lumbricillus the testes are enclosed in a testis sac within which the male cells mature, by one possible exception a unique feature among Oligochaeta, The other enchytraeid genera studied and Oligochaeta in general lack this sac and the male cells mature directly in the cavity of the testicular segment. Secondly, species of Enchytraeus and Lumbricillus generally have a higher reproductive output than species of the inland terrestrial branch and this may represent an adaptation to the unpredictable littoral zone compared to the more stable nature of inland habitats. In the older literature the genus Mesenchytraeus is considered to have a basic position within the entire family but our molecular data do not support this expectation. In Enchytraeidae the nephridia are elaborate organs of a characteristic and constant shape covering species from different genera in a pattern following the molecular phylogeny. Other much used morphological features such as shape of setae, anteclitellar origin of the dorsal vessel and various modifications of the intestine have arisen more than once.     

A taxonomic and faunistic survey of the marine Tubificidae and Enchytraeidae (Oligochaeta) of Italy. Introduction and preliminary results

On the basis of material collected along the Ligurian, Tyrrhenian, Ionic and Adriatic coasts of Italy, a tentative list of 26 species (18 tubificids, 8 enchytraeids) of marine Oligochaeta is presented. Most of the species are new to science, and it can therefore be concluded that there is a very high diversity of oligochaetes in the Mediterranean Sea.     

Bioaccumulation of lindane and hexachlorobenzene by the oligochaetes Enchytraeus luxuriosus and Enchytraeus albidus (Enchytraeidae,Oligochaeta, Annelida)

The uptake of chemicals in soil organisms, especially earthworms, has been studied many times. However, in Europe no internationally accepted standardised test guideline for the assessment of bioaccumulation in the soil ecosystem exists. Therefore, the German Federal Environmental Agency recently funded a project in which a standardisable test method for measuring bioaccumulation of chemicals using earthworms and enchytraeids is being developed. In this contribution, initial results with the new method are presented, using two model chemicals (the insecticide lindane and the fungicide hexachlorobenzene). Two enchytraeid species (Enchytraeus luxuriosus and Enchytraeus albidus) were selected as test organisms due to their easy handling and their important ecological role in the soil compartment. Artificial soil and a natural standard soil were used as test substrates. Test concentrations were based on previous results of acute and reproduction toxicity tests performed with the same species. Uptake as well as the elimination of the test substances were examined under standardised conditions in a closed test system. The first results show that both chemicals were accumulated considerably by both enchytraeid species. The bioaccumulation factors (BAFs) of lindane and hexachlorobenzene found for enchytraeids are significantly higher compared to those for lumbricid earthworms. Evaluation of the preliminary data suggests that the smaller species E. luxuriosus accumulated the two chemicals to a greater extent than E. albidus. In most cases, both chemicals were eliminated completely. The use of this new test method appears suitable for the ecotoxicological risk assessment of bioaccumulative chemicals.     

Population dynamics and functional roles of Enchytraeidae (Oligochaeta) in hardwood forest and agricultural ecosystems

Population dynamics of enchytraeids are described for 2 montane forested watersheds in southwestern North Carolina (Coweeta) and an agricultural site under conventional (CT) and no-tillage (NT) management in the northeastern Georgia piedmont (Horseshoe Bend, HSB). Given that much of the taxonomy, ecology and community structure of enchytraeids is poorly known, our objective was to identify key indicators of enchytraeid community structure which could be used, in this case, to better understand their role in soil structure formation. Although population densities of enchytraeids were higher in the forested (Coweeta) than in the arable soils (HSB), the average ash free dry weight per enchytraeid at HSB was nearly double that found at Coweeta. Based on these measurements and an estimate of their gut transit time, we calculated that the enchytraeids at HSB transported 2180 g of soil per m² per year compared to 443 and 393 g m^-2 yr^-1 for watershed 18 and 27, respectively at Coweeta. We therefore hypothesize that enchytraeids have a larger influence on soil structure in agricultural fields than in forested areas, in spite of lower population densities. The ash free dry weight and ash wt. per enchytraeid may qualify as key indicator parameters of enchytraeid community structure which helps to understand their functional role in ecosystems, though more studies are called for.     

Species separation and identification in the Enchytraeidae (Oligochaeta, Annelida): combining morphology with general protein data

In the Enchytraeidae, species separation and identification is often problematic due to high morphological similarity of closely related species and considerable intraspecific variability of crucial characteristics. Immature specimens are almost undeterminable. To meet these difficulties, this paper recommends the consulting of general protein patterns as exhibited by non-specific silver-staining after isoelectric focusing. A method is presented which allows the successful inclusion of protein data in taxonomic studies and field surveys. Two examples from an investigation on Fridericia field populations show that, with the help of general protein pattern analysis, a clear taxonomic decision on the identity of morphologically aberrant forms and of juvenile specimens as well can be achieved with comparatively little expenditure of time. A combined use of morphological and protein data for taxonomic purposes is suggested.     

Phylogenetics of some Enchytraeidae (Annelida: Oligochaeta): A preliminary investigation of relationships to the Haplotaxidae

In phylogenetic considerations of the Oligochaeta and the family Enchytraeidae, Propappus has been considered the ancestral or even the archetypal enchytraeid genus. Three nominal species are presently included in Propappus Michaelsen, 1905, P. volki Michaelsen, 1916, P. arhyncotus Sokolskaja, 1972, and the type species of the genus, P. glandulosus Michaelsen, 1905. Examination of type material of P. glandulosus and P. volki, as well as other material of the latter, showed that these species have a single pair of testes in segment XI and a single pair of ovaries in segment XIII. According to current classifications of the Oligochaeta, these species of Propappus cannot be retained in the Enchytraeidae. A phylogenetic analysis including two species of Propappus and 29 species of Haplotaxidae suggest a sister group relationship between Propappus and some Enchytraeidae and Haplotaxidae.     

Population dynamics and energy budget of Marionina southerni (Cernosvitov) (Enchytraeidae,Oligochaeta) in the shallow littoral of Lake Esrom,Denmark

Marionina southerni (Cernosvitov) was numerically the dominant oligochaete in a shallow, strongly exposed surf zone locality (0–1 m depth) in the mesotrophic Lake Esrom. It comprised 21,500 ind m^–2 or nearly 50% of the total oligochaete community, which otherwise was dominated by Nais spp. and the lumbriculid Stylodrilus heringianus Claparède. M. southerni appears to have a 1-y life cycle. Individual biomass ranged from 3 to 48 µg ash free dry weight. Annual net production at the site was 5.1 kcal m^–2 (size-frequency method) with a P/B ratio of 2.5. This is about 0.5% of the estimated mean zoobenthic production in the littoral zone from 0 to 2 m depth in Lake Esrom. At 5° C M. southerni showed a constant oxygen uptake down to 25% oxygen saturation, but practically no regulatory respiration was found at 20 °C. In the field M. southerni was never found in sediment with less than 60% oxygen saturation. The annual community respiration of M. southerni was 14.2 kcal m^–2, and annual assimilation thus made up 19.3 kcal m^–2 with a net production efficiency of 26.5%.     

甘肃陆栖寡毛类一新属新种(寡毛纲:近孔目:线蚓科)

栖居于名贵中药当归 Angelica sinensis(Oliv.)Diels根部的蚯蚓经鉴定为线蚓科(Fnchytraeidae)的一新属新种——岷县等毛蚓 Isosetosa minxianensis。新种的主要特征:头孔位于O/I,无背孔,体白色,环带位于1/2Ⅺ—ⅩⅢ(=21/2节)。每节刚毛4束,每束刚毛4根,每根棍棒状,外端略尖。受精囊孔一对,位4/5节间沟内。雄孔一对,位第Ⅻ节。雌孔一对,位于12/13节间沟内。脑位于第Ⅲ节内。在脑和腹神经索的切面内可见到神经原的核周体。隔膜腺三对,位于4/5—6/7隔膜的后壁上。咽头顶部具有扁平板。无肠盲囊。在第Ⅳ节内有消化肾管、乳糜细胞。背血管起目环带后。精巢一对,不分叶,位于第Ⅺ节内。卵巢一对,位于第Ⅻ节内,具精囊和卵囊,阴茎球为带丝蚓型。受精囊一对,位于第Ⅴ节内,不与消化道相连,亦无盲管分支。本新属与白线蚓属 Fridericia Michaelsen、线蚓属 Enchytraeus Henle相近,但有明显差异。经与Enchytraeus barkudensis Henle进行比较,也有明显差別,本种的受精囊不与消化道相连,肠壁内有乳糜细胞,故确定为新属新种。经过调查,本种蚯蚓有时少数也在健康的当归根部生活,因此也可能直接为害健康植株。     

Taxonomy and molecular phylogeny of the Asian Paraleucophenga Hendel (Diptera,Drosophilidae)

This paper reports on nine Asian species of the genus Paraleucophenga, of which four are new to science: Paraleucophenga brevipenis sp. nov. , Paraleucophenga hirtipenis sp. nov. , Paraleucophenga longiseta sp. nov. , and Paraleucophenga tanydactylia sp. nov. We also report on a new synonym, Paraleucophenga shanyinensis Chen & Toda, 1994 syn. nov. A key to all of the species examined, based on morphological data, is provided, together with a ‘molecular’ key to seven Paraleudophenga species based on DNA sequence data of the mitochondrial NADH dehydrogenase subunit 2 (ND2) gene. The phylogenetic relationships among seven Paraleucophenga species are reconstructed based on DNA sequences of the mitochondrial ND2 gene, using two Leucophenga species as outgroups. © 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2009, 155 , 615–629.     

Fridericia larix sp. nov. (Enchytraeidae, Oligochaeta) from Irish soils

A new species of Fridericia (Enchytraeidae, Oligochaeta) is described from soils in Ireland. It was found during sampling campaigns in the framework of a comprehensive taxonomic revision of the genus (Schmelz, 2003. Taxonomy of Fridericia (Oligochaeta, Enchytraeidae). Revision of species with morphological and biochemical methods. Abh. Naturw. Ver. Hamburg, N.F. 38, 1–415, figs. 1–73), but it was not included in that study. Fridericia larix sp. nov., named in reference to the type locality, belongs to the large and taxonomically difficult group of species with two diverticula per spermatheca. It is distinguished from all known congeners by the following combination of characters: (1) a maximum of four chaetae in ventral preclitellar bundles; (2) oesophageal appendages poorly branched; (3) no pharyngeal glands in segment VII; (4) coelomocytes without refractile vesicles; (5) clitellum girdle-shaped, cell distribution alike on all sides; (6) bursal slit of male copulatory organ mainly transverse; (7) no subneural glands; (8) spermathecal diverticula not stalked. Further distinguishing characters are: (9) an asymmetrical arrangement of chaetae in the first lateral postclitellar bundles, with one large chaeta and one small chaeta per bundle (Fig. 1b, “lc XVI”); (10) the length ratio of spermatozoa to spermatozoal nuclei (6:1–7:1); and (11) a wavy inner surface in parts of the epithelium of the spermathecal ampulla (Fig. 1i, arrow).See also Electronic Supplement at: http://www.senckenberg.de/odes/05-05.htm     

Comparative ultrastructural study of the cuticle and spermatozoa in Propappus volki Michaelsen, 1916 (Annelida: Clitellata)

The ultrastructure of the cuticle and mature spermatozoa of the oligochaete Propappus volki Michaelsen, 1916 is described with the aim of providing additional data for clarifying the systematic position of the taxon. P. volki is a fresh-water species living in streams, and is easily recognized by its proboscis on the pre-segmental prostomium and, in mature specimens, by a clitellum covering the segments XII–XIV. The cuticle is composed of a proximal fibre zone and a distal layered epicuticle covered with membrane-bound epicuticular projections. The fibre zone consists of collagenous fibres in a matrix, arranged in either densely packed parallel layers with the fibres oriented in the same direction, or with more loosely distributed fibres, although with the same main orientation. The epicuticular projections are pyramidal with the base leaning on the outer surface of the epicuticle. The cuticle covering the proboscis differs in morphology from that of the rest of the worm; the fibre zone is composed of thin and short fibrils running in all directions, and the epicuticular projections are longer and more narrow than the projections in other regions of the worm.

The spermatozoa are filiform cells formed, in sequence, by an acrosome, an elongated nucleus, a long midpiece, and a flagellum. The acrosomal tube is short and straight with a completely external acrosomal vesicle. Following the acrosome is a apically corkscrew-shaped and basally straight nucleus. The midpiece is twisted and formed by five mitochondria. The flagellum shows a prominent central sheath arrangement.

A comparison with ultrastructurally described cuticles and spermatozoa from other clitellate species reveals most similarities with enchytraeids.     

Cryptic diversity among the achaetous Marionina (Annelida,Clitellata, Enchytraeidae)

This study investigates the diversity and taxonomy of a mainly marine group of species lacking chaetae currently assigned to the genus Marionina. This achaetous group includes four nominal species: M. achaeta (Hagen, 1954 Hagen, G. 1954. Michaelsena achaeta nov. sp., ein neuer mariner Oligochaet aus der Kieler Bucht. Faunistische Mitteilungen aus Norddeutschland, 1: 12–13.  [Google Scholar]), M. achaeta sensu Lasserre, 1964 Lasserre, P. 1964. Notes sur quelques oligochètes Enchytraeidae présents dans les plages du Bassin d’Arcachon. Procés-Verbaux des Séances de la Société Linnéenne de Bordeaux, 101: 87–91.  [Google Scholar], M. nevisensis Righi & Kanner, 1979 Righi, G. and Kanner, E. 1979. Marine Oligochaeta (Tubificidae and Enchytraeidae) from the Caribbean Sea. Studies of the Fauna of Curaçao and other Caribbean Islands, 58: 44–68.  [Google Scholar] and M. arenaria Healy, 1979 Healy, B. 1979a. Marine fauna of County Wexford. 1 – Littoral and brackishwater Oligochaeta. The Irish Naturalists' Journal, 19: 418–422.  [Google Scholar]. As Lasserre's (1964 Lasserre, P. 1964. Notes sur quelques oligochètes Enchytraeidae présents dans les plages du Bassin d’Arcachon. Procés-Verbaux des Séances de la Société Linnéenne de Bordeaux, 101: 87–91.  [Google Scholar]) M. achaeta appears to be morphologically different from its (then) senior homonym M. achaeta (Hagen, 1954 Hagen, G. 1954. Michaelsena achaeta nov. sp., ein neuer mariner Oligochaet aus der Kieler Bucht. Faunistische Mitteilungen aus Norddeutschland, 1: 12–13.  [Google Scholar]), the replacement name M. nothachaeta nom. nov. is proposed for it. We studied the genetic and morphological diversity of achaetous specimens of Marionina collected in Florida, the Great Barrier Reef, New Caledonia, Sweden, England and the Bahamas. The collection localities are almost all supralittoral and often brackish-water habitats. Parts of the mitochondrial genes 12S, 16S, COI and the nuclear genes 18S, 28S and ITS were analysed to assess the genetic variation and phylogeny of the achaetous Marionina species. The molecular data reveal one monophyletic group of 11 separately evolving lineages, and between these lineages, K2P distances in the barcoding gene COI vary between 5.4 and 25.0%. On a morphological basis, the lineages could be assigned to seven different groups (morphotypes), of which only two could be identified as described nominal taxa: M. nevisensis s. lat. (several lineages) and M. nothachaeta. Since the former taxon appears to be a complex of cryptic species around the world and the original type material no longer exists, a neotype from the Caribbean was designated for M. nevisensis s. str. The remaining achaetous lineages represent five morphologically distinct species that are left unnamed, awaiting finer morphological scrutiny and detailed comparisons with new collections of M. achaeta and M. arenaria. Summing up, the group of achaetous Marionina now seems to contain up to 13 different species, seven of which are yet to be formally described and named.     

First reports of Grania (Clitellata: Enchytraeidae) from Africa and South America: molecular phylogeny and descriptions of nine new species

In this article, our knowledge of the geographic distribution of Grania species is expanded by describing seven new species, G rania bekkouchei sp. nov. , G rania brasiliensis sp. nov. , G rania capensis sp. nov. , G rania chilensis sp. nov. , G rania cryptica sp. nov. , G rania hinojosai sp. nov. , and G rania simonae sp. nov. , from poorly investigated regions of the Southern Hemisphere, plus two new species, G rania carolinensis sp. nov. and G rania unitheca sp. nov. , from off the east coast of the USA. An immature achaetous specimen that we call Grania cf. levis was also included. The newly generated data were combined with a previously published data set in order to update the hypothesis of phylogenetic relationships among Grania species. All new species except G . cryptica sp. nov. are supported by both morphological and molecular data. In addition, we find that G . chilensis sp. nov. is structured in at least four distinct populations along the Chilean coast. The species described from South Africa form a monophyletic clade where two are morphologically indistinguishable but diverging in both mitochondrial and nuclear ribosomal genes, and thus we describe them as different species, G . bekkouchei sp. nov. and G . cryptica sp. nov. Among the North Carolinian species, G . unitheca sp. nov. is indicated as a close relative of Grania monospermatheca Erséus & Lasserre, 1976, and G . carolinensis sp. nov. is indicated as a close relative of G. cf. levis. The updated phylogeny is strongly concordant with geographical species distributions, thus supporting a low level of dispersal within this genus, as has previously been hypothesized. © 2015 The Linnean Society of London