Comparison of three different extraction methods for Turbellaria

Abstract

Three different extraction methods for Turbellaria were compared, 2 of which use living material. The first method is based on sea-water ice treatment (Uhlig-method), the second employs decantation of narcotized fauna (MgC1,-method). The third method is the Bamett-method, performed on preserved material. Three series of 12 samples each were analysed quantitatively. Turbellaria were counted and identified to the order level. For the turbellarian population, as a whole, the numbers of individuals extracted alive (Uhlig-or MgC1,-method) was less than 50 % of the number extracted from the preserved samples (Barnett-method). Differences between Uhlig-method and MgC1,-method were not statistically significant. However, for Acoela and Retronectida, the Uhlig-method was more efficient than both other methods. We conclude that for a reliable quantitative analysis of Turbellaria 2 different extraction methods are required: one should employ extraction of living material (Uhligmethod) and one extraction of fixed material. For qualitative investigations extract~on of living material is recommended.

Quantitative extraction of living meiofauna from marine and brackish muddy sediments

“…For marine sediments, various methods have been proposed (see Uhlig 1964, Hulings & Gray 1971, Uhlig et al 1973, Martens 1984, Noldt & Wehrenberg 1984. However, in investigating Plathelminthes of marine and brackish muddy sediments, which often enclose rootage or fragments of roots, we found no method satisfying the following demands: (1) quantitative extraction; (2) extraction of undamaged living animals (needed for determination of species, e.g.…”

Synoptic patterns of meiofaunal and macrofaunal abundances and specific composition in littoral sediments

“…None of the previously used methods of meiofaunal extraction yields quantitative extraction in all types of sediment and on all meiofaunal taxa (Martens, 1984;Noldt & Wehrenberg, 1984;Armonles & Hellwig, 1986). Therefore, all the sediment was divided into Petri dishes and meiofauna was sorted from these dishes.…”

“…Depending on the studied taxon and the type of sediments, different methods of extraction were used. The seawater-ice method (Uhhg et al, 1973} proved useful for the extraction of Ciliata and some other taxa from relatively pure sand (Schmidt, 1968;Martens, 1984}. The meiofauna of sheltered faunal differences leading to significant deviations of abundance from randomness is due to these differences in sediment composition.…”

Two new species of the genusmonocelisehrenberg, 1831 (platyhelminthes: Proseriata) from the mediterranean, with a redescription ofmonocelis lineata(O. F. müller, 1774)

“…Monocelis párvula has a peculiar karyotype, with one large, and two small chromosome pairs, about 2 um long. Similar small chromosomes are found in only a few Monocelis species: M. lineata, M. longistyla Martens &Curini-Galletti, 1987, andM. fusca Oersted, 1843, all from Mediterranean and/or northern Atlantic -whose haploid genome length is around 7 urn or smaller (Martens & Curini-Galletti, 1987).…”