Nematodes of the Order Tylenchida in Germany – the Non-Phytoparasitic Species
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88 (1) · April 2016 pp. 19–41 Nematodes of the order Tylenchida in Germany – the non-phytoparasitic species Dieter Sturhan1* and Karin Hohberg² 1 Arnethstr. 13D, 48159 Münster, Germany and c/o Julius Kühn-Institut, Toppheideweg 88, 48161 Münster, Germany ² Senckenberg Museum of Natural History Görlitz, Am Museum 1, 02826 Görlitz, Germany * Corresponding author, e-mail: [email protected] Received 15 February 2016 | Accepted 30 March 2016 Published online at www.soil-organisms.de 1 April 2016 | Printed version 15 April 2016 Abstract In the recently published checklist of plant-parasitic nematodes known from Germany (Sturhan 2014) genera and species of the order Tylenchida, which are generally considered as being parasites of higher plants, represent the largest taxonomic group with 212 species. The present paper gives an overview of the remaining trophic groups in Tylenchida: Root tip feeders, myceliophagous species and entomoparasites, the latter often having a free-living soil generation. A total of 165 species are included, most of them representatives of the suborder Hexatylina (96 species), followed by members of Tylenchina (67 species). Where available, first records for Germany are given together with data on habitat, distribution and the hosts of zooparasitic species. A high number of valid species (95) were originally described from Germany; 20 additional species have been synonymised with previously described species or are considered as species inquirendae. Published data are critically reviewed and some new records are added. Many published records are considered as questionable and need verification. Part of the species is deficiently characterised and requires further study. The number of unidentified and still undescribed species appears to be high. Two obviously newTenunemellus species as well as a nematode population isolated from soil, which could not be attributed to any of the currently known tylenchid genera, are briefly characterised. An obviously still undescribed species of Paurodontoides is recorded and morphological characteristics are presented: it is the first record of the genus outside USA. Morphological characters of Boleodorus clavicaudatus populations from Germany are given and compared to the original description. Supplementing morphological characters of Pleurotylenchus sachsi and data on occurrence, habitat and distribution in Germany are presented. A Safianema population recovered in southern Germany, resembling S. lutonense, is briefly characterised morphologically. Keywords Biodiversity | entomoparasitic nematodes | free-living soil nematodes | Hexatylina | mycophagous nematodes | nematofauna | Paurodontoides | Pleurotylenchus | Safianema | Tylenchina 1. Introduction back to Meyl (1961) on free-living soil and freshwater nematodes and to Sprehn (1961) on zooparasitic Nematodes with an estimated number of about 2000 nematodes. Faunistic publications from more recent species are ranking in the second position among times were generally confined to individual taxa or the ca. 48000 animal species known from Germany, selected trophic groups or biota, and no comprehensive following Arthropoda as the largest group (http://www. publications covering the entire order Nematoda are bfn.de/index/htm). However, estimates about nematodes available. But during the past decades there has been are highly speculative, because no updated lists of a remarkable increase of publications containing data nematodes exist. The last comprehensive publications on nematode species, their presence and distribution in about nematodes in Germany (or Central Europe) date Germany, and updating and summarizing the present © Senckenberg Museum of Natural History Görlitz · 2016 ISSN 1864-6417 20 Dieter Sturhan & Karin Hohberg state of knowledge about the nematode fauna of Germany 2. Classification is highly required. The recently published checklist of plant-parasitic For convenience, similar to Sturhan (2014), the nematodes (Sturhan 2014) may be considered as an classification of tylenchid nematodes in ‘Fauna updated contribution to a ‘Nematofauna Germanica’, Europaea’ (www.fauna-eu.org) is also mostly used in the but it is restricted to those nematodes, which are present paper. Exceptions are indicated in the respective generally considered as feeding on vascular plants taxa chapters. The classification is largely identical and being of potential economic significance as plant with that proposed by Siddiqi (2000), with Tylenchina, pests. In this trophic group, members of the nematode Hoplolaimina, Criconematina and Hexatylina as orders Tylenchida, Aphelenchida, Dorylaimida (fam. suborders, and considering Aphelenchida as a separate Longidoridae) and Triplonchida (fam. Trichodoridae) are order. Almost all taxa included in the present checklist included. are grouped in Tylenchina and Hexatylina. Only the Among these phytoparasitic nematodes, Tylenchida family Psilenchidae Paramonov, 1967 with Psilenchus with a total of 212 species currently mostly considered de Man, 1921 as the only genus known from Germany as valid, are forming the largest group of species. is arranged in Hoplolaimina for the time being, because Sturhan (2014) listed all members of the Tylenchida morphological as well as molecular characters are suborders Criconematina and Hoplolaimina (except indicating distinction from other taxa in Tylenchina. Also fam. Psilenchidae) among the plant-parasitic nematodes, Siddiqi (2000), Loof (2001) and Andrássy (2007) listed likewise from the suborder Tylenchina the family Psilenchidae as distinct from other taxa in Tylenchina, Tylodoridae with the genera Cephalenchus Goodey, whereas Geraert (2008) arranged Psilenchinae as a 1962 and Pleurotylenchus Szczygieł, 1969 and from the subfamily in Tylenchidae. family Anguinidae the genera Anguina Scopoli, 1777, The genera and species of non-phytoparasitic Subanguina Paramonov, 1967, Halenchus N.A. Cobb Tylenchida known from Germany and their taxonomic in M.V. Cobb, 1933 and the plant-parasitic species of position are shown in the overview below. Different from the genus Ditylenchus Filipjev, 1936. The suborder Geraert (2008), Atylenchidae Skarbilovich, 1959 and Hexatylina with a total of 25 genera known from Germany Ecphyadophoridae Skarbilovich, 1959 are considered is included in the present publication for the first time. as families separate from Tylenchidae (Tylenchinae Main objective of the present publication is to extend in the sense of Geraert 2008). In agreement with the previous checklist (Sturhan 2014) to include all Geraert (2008), we accept synonymisation of the genus other members of the order Tylenchida recorded from Ottolenchus (Andrássy, 1954) Siddiqi & Hawksworth, Germany: besides the ‘plant nematodes’ the mycophagous 1982 with Filenchus Andrássy, 1954. The genus soil-inhabiting species and nematodes associated with or Safianema Siddiqi, 1980, which had been considered parasitic in insects and a few other arthropods. Only some as synonym of Ditylenchus by Brzeski (1991, 1998), is taxa of this last group had been included previously in accepted as valid and a separate genus in Anguinidae. the book publications by Meyl (1961) and, in particular, In “Fauna Europaea” the genera Sychnotylenchus Rühm, that by Sprehn (1961), whose information on zooparasitic 1956, Prothallonema Christie, 1938 and most species of Tylenchida is almost confined to a brief key of genera Neoditylenchus Meyl, 1961 are so far not yet enclosed mentioning few species only. among the nematodes known from Europe. The revised Knowledge of presence (or absence) of nematode classification of Hexatylina proposed by Chizhov species in Germany may be considered as a basis for (2004) has not been considered in the present paper, correct identifications and will hopefully stimulate future but the synonymy of Paurodontidae Thorne, 1941 with research on species diversity of this nematode group in Sphaerulariidae Lubbock, 1861, supposed by Siddiqi Germany and fill the gaps in knowledge of the species (2000) and accepted by Andrássy (2007) and Handoo et present, their geographical distribution and their habitats. al. (2010), is followed. In the present publication particular importance is given In the overview below, the families distinguished on providing information about those species, which had in each suborder and each superfamily are arranged in originally been described from Germany. Type specimens alphabetical order, likewise the genera within each family. and voucher specimens have not been retained of most Most members of the suborder Tylenchina and species of these species. Recollection of material, designation of the genus Psilenchus in Hoplolaimina are migrating and deposition of neotypes are highly recommended soil nematodes, which feed on root hairs, epidermal and resampling of identified specimens at or close to the cells, and/or fungal hyphae (Yeates et al. 1993). Members type localities are considered as a prerequisite to future of Sychnotylenchidae are mostly associated with bark molecular studies and barcoding of species. beetles and found in frass of beetle galleries in trees or SOIL ORGANISMS 88 (1) 2016 Nematodes of the order Tylenchida in Germany – the non-phytoparasitic species 21 tree trunks (Rühm 1956), presumably feeding on fungi. HEXATYLINA Most members of Hexatylina are parasites in insects or mites, many of these with a free-living mycetophagous Sphaerularioidea (soil) generation alternating with a parasitic generation Allantonematidae (Siddiqi 2000). Allantonema Leuckart,