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.     

Factorial correspondence analysis of oligochaeta communities according to eutrophication level

In 1976, 31 sediment cores were taken between the 50 and 310 m isobaths in Lake Geneva (Switzerland). Communities of Tubificidae and Lumbriculidae were used to characterize sampling stations. These results were analysed with factorial correspondence analysis. Differences in worm communities, due to microdistribution and seasonal variation inside location, were small compared with differences between sampling stations. Locations from a previous study classified as polluted and not polluted by chemical and biological criteria were entered into the analysis as reference stations. Distance on the factorial plots between studied and reference stations indicated their pollution level. Positions of worm species around sampling locations allowed these to be classified as indicators of pollution level. Since 1962 pollution has modified worm communities between the 150 and 310 m isobaths. Deep water stations, where oxygen is low, have a fauna similar to shallow water stations near the sewage outfall of Vidy. Tubifex tubifex is present in the most polluted conditions. Stylodrilus heringianus is an indicator of unpolluted conditions. Potamothrix vejdovskyi, P. heuscheri and P. hammoniensis can be used to indicate a gradient of increasing pollution.     

中国水栖寡毛类的研究 Ⅳ.仙女虫科和颤蚓科的新记录和稀有种

本文共记载仙女虫科和颤蚓科的9个种,其中6个种是国内新记录,即森珀头鳃虫（Branchiodrilussemperi）、三齿尾盘虫（Derotrifida）、平叉吻盲虫（Pristinasynclites）、坦氏泥蚓（Ilyodrilustempletoni）、美洲管水蚓（Aulodrilusamericanus）、维氏沼丝蚓（Telmetodrilusvejdovskyi）;同时将一亚种［昌都两栖吻盲虫（Pristinaamphibiorticachangtuensis）］提升为种［昌都小吻盲虫（Pristinellachangtuenssisstat．etcomb．nov．）］。     

Production of some oligochaete species in large Estonian lakes

The production of Potamothrix hammoniensis, Lamprodrilus isoporus, and Uncinais uncinata was estimated in the eutrophic lakes Peipsi-Pihkva and Vôrtsjärv. Growth characteristics of these species are briefly described. Calculated production values were 6–32 (P. hammoniensis), 19–79 (L. isoporus), and 1–4 kJ m² (U. uncinata), respectively. The annual P/B ratios for the same species were, 0.8–1.7, 2.5–4.8, and 4.4–5.4, respectively.     

Opportunist rotifers: colonising species of young ponds in Surrey,England

Quantitative substrate samples were collected at a newly constructed gravel bar habitat in the Tombigbee River, Mississippi, to characterize oligochaete (naididae and tubificidae) species richness and community composition. A total of 28 species of naidid and tubificid worms were indentified during the three-year study; Nais pardalis, Dero nivea, D. obtusa, Pristina aequiseta (naididae), and Branchiura sowerbyi (Tubificidae) were dominant. In June, 1985, three months after construction, 30 samples yielded seven taxa of oligochaetes; naidid and tubificid densities (± standard deviation) were 12.9 (± 29.7) and 10.1 m^–2 (±39.6), respectively. In October, 1985, 20 taxa were identified, and naidid and tubificid densities were 387.9 (± 300.5 and 22.9 m^–2 (± 50.7), respectively. Tubificid densities were highest in the spring, except during the first year, and naidid densities showed their highest densities in the fall during all years. Dominance changed from Nais pardalis and Dero nivea during the first year to Pristina aequiseta and D. nivea during the last year. The naididae, which typically inhabit gravel, exhibited more uniform colonization patterns than did the tubificidae. Comparatively low densities characterized the oligochaete community during the first year and high naidid densities during the last. Because this gravel bar is relatively isolated from similar substrates, and since oligochaetes disperse only via drift or crawling, colonization processes have been slow.     

Some ecological aspects of aquatic oligochaetes in the Lower Pearl River (People's Republic of China)

Densities of the 8 most important species or genera of the 15 taxa found at a series of stations along the Guangzhou Reach of the Pearl River are given. Shannon-Weaver diversity index values were low throughout the area studied. No clear correlations were found between oligochaetes and NH₃-N or a combination of 6 chemical factors (COD, NH₃-N, NO₃-N, Cr, Pb, Hg). However, when the main groups of the benthos, including the oligochaetes, were taken together, and a BPI (Biological Pollution Index) approach used, a correlation between the macroinvertebrate community and the combined chemical factors was noted.     

Distribution and ecology of Middle Atlantic Bight Oligochaeta

Distribution and ecology of continental shelf oligochaetes are poorly understood. From 1975 through 1977 baseline ecological studies were conducted in the Middle Atlantic Bight prior to oil exploration activities. A total of 38 species in three oligochaete families were collected. Of this total one family and 29 of the species were undescribed at the time of collection. The most abundant and widely distributed species were Limnodriloides monothecus, L. medioporus, Bathydrilus longus, Phallodrilus biprostatus, and Tubificoides diazi. No single species dominated the oligochaete fauna. All the oligochaete species responded to changes in physical parameters over the shelf similarly to the total macrofauna. Seasonal trends within the oligochaetes were not found. Species that preferred coarser sand sediments were all small interstitial forms. The finer sand and eurytopic species were all burrowers. Zoogeographically the Middle Atlantic Bight oligochaetes were predominantly temperate (16 species) with some southern species (8). Seven species were broadly distributed from the Caribbean to Massachusetts or around the world. Seven species were only known from the area studied.Contribution No. 1397 of the Virginia Institute of Marine Science.     

Sublittoral and profundal Oligochaeta fauna of the Lake Constance (Bodensee-Obersee)

Fourteen tubificid species and one lumbriculid make up the oligochaete population of the northern half of Lake Constance, a meso- to mesoeutrophic lake. Tubifex tubifex makes up 72% of the total abundance, the clean water species Stylodrilus heringianus only 0.1%. No correlation exists between total worm abundance and organic carbon content of the sediment, only 4% of the organic carbon being used by the worms. A highly significant correlation between particulate organic matter loading and its organic carbon content from 10 tributaries and total oligochaete abundance is demonstrated. The ecological index I_PA is defined and used to assess the biologically relevant trophic status of the lake bed. This integrates information on the percent representation of three groups of worm species classified on atrophic basis and total abundance of the worms. Despite control of the increase in phosphorus loadings progressive eutrophication of sediments was observed after an 8 year interval.     

海南岛陆栖寡毛类二新种记述(寡毛纲:巨蚓科)

1982年采自海南岛尖峰岭热带原始森林的巨蚓科(Megascolecidae)远盲,属Amynthas蚯蚓二新种:双陷远盲蚓 Amynthas biconcavus sp.nov.和四突远盲蚓 Amynthas tetrapapillatus sp.nov.。文中采用的是Sims & Easton 1972和Easton 1979对环毛属Pheretima订正后的分属系统。