Pellioditis Dougherty, 1953

Sudhaus, Walter, 2023, An update of the catalogue of paraphyletic ‘ Rhabditidae’ (Nematoda) after eleven years, Soil Organisms 95 (1), pp. 95-116 : 106-107

Pellioditis Dougherty, 1953

syn. Phasmarhabditis Andrássy, 1976 :

Pelodera papillosa Schneider, 1866

Type species: Pelodera pellio Schneider, 1866 Based on morphology there is a clade encompassing Pellioditis pellio and the species labelled Phasmarhabditis which Sudhaus (1976) called the Papillosa group ( Sudhaus & Fitch 2001). This systematisation has never been taken into account, however, and the synonymy of Phasmarhabditis has been ignored. However, sequence data for the type species P. pellio will be soon published, showing that it belongs to the same clade as Phasmarhabditis . According to the systematic position of Agfa and Angiostomatidae , Pellioditis is possibly paraphyletic ( Nermuť et al. 2016a, 2017, Tandingan De Ley et al. 2016, Pieterse et al. 2021, Gorgadze et al. 2022, Ivanova et al. 2023). However, the phylogenetic position of Angiostoma has not yet been convincingly shown, especially since only representatives of the Gastropoda bound Limacis group are analysed and not the Plethodontis group living parasitic in Tetrapoda.

The Pellioditis species are necromenic in earthworms and terrestrial gastropods. Dauer juveniles can survive in soil. Some species live like parasitoids, first being parasitic and finally killing their former hosts ( Sudhaus 2008). In analogy to entomo-pathogenic nematodes, this life-cycle might be called ‘gastropod-pathogenic’. They are thus used as biological control agents for slugs and snails.

Seven valid species were listed in catalogue 2011, P. tawfiki ( Azzam, 2003) with reservations ( Sudhaus 2018) (see ‘Comments on dubious species’ p. 110). Since then 15 species have been described as new.

• P. akhaldaba ( Ivanova, Gorgadze, Lortkhipanidze & Spiridonov, 2021) comb. n. – Akhaldaba, Georgia; in the slug Deroceras reticulatum ; also baited with Galleria cadavers from garden soil. – In cupola-shaped females phasmids open on the spine.

• P. apuliae ( Nermuť, Půža & Mráček, 2016) comb. n. – Bari, southern Italy; from the slug Milax sowerbyi in the garden of the University.

• P. bohemica ( Nermuť, Půža, Mekete & Mráček, 2017) comb. n. – near Chelčice, Czech Republic; from Deroceras reticulatum from a red currant plantation; also baited from soil samples with Galleria larvae.

• P. bonaquensis ( Nermuť, Půža, Mekete &Mráček, 2016) comb. n.; emendation of Phasmarhabditis bonaquaense Nermuť, Půža, Mekete & Mráček, 2016 by D. J. Hunt (Nematology 24, 2022, p. 232) – České Švýcary, near Dobrá Voda, Czech Republic; from the slug Malacolimax tenellus .

• P. californica ( Tandingan De Ley, Holovachov, Mc Donnell, Bert, Paine & De Ley, 2016) comb. n. – Eureka, California, USA; obtained from a cadaver of the slug Deroceras reticulatum .

• P. circassica ( Ivanova, Geraskina & Spiridonov, 2020) comb. n. – Nickel settlement, Adygea Republic, Russia; from the snail Oxychilus cf. difficilis , in deciduous forest.

• P. clausiliiae ( Ivanova, Geraskina & Spiridonov, 2020) comb. n. – near Georgievsk, Stavropol district, Russia; from Clausiliidae snails (cf. Quadriplicata sp. ) in decidous forest.

• P. huizhouensis ( Huang, Ye, Ren & Zhao, 2015) comb. n. – Kowloon Peak of Huizhou City, Guangdong Province, China; in rotting leaves.

• P. kenyaensis ( Pieterse, Rowson, Tiedt, Malan, Haukeland & Ross, 2021) comb. n. – Nairobi, Kenya; from the slug Polytoxon robustum in a garden.

• P. meridionalis ( Ivanova & Spiridonov, 2017) comb. n. – Cát Tiên National Park, southern Vietnam; from the land snail Quantula striata .

• P. quinamensis ( Ivanova & Spiridonov, 2022) comb. n. – Cát Tiên National Park, southern Vietnam; from the land snail Sesara sp .. Further isolates from seven additional genus taxa of terrestrial snails in that National Park. – Special is three separate lips by fusion in pairs and GP1 shifted anteriorly to beginning of bursa velum.

• P. safricana ( Ross, Pieterse, Malan & Ivanova, 2018) comb. n. – near George, Western Cape province, South Africa; from the slug Deroceras reticulatum from a nursery.

• P. thesamica ( Gorgadze, Troccoli, Fanelli, Tarasco & De Luca, 2022) comb. n. – Tezami, East Georgia; from a dead Deroceras reticulatum slug in a raspberry garden.

• P- villasmundi (Ivanova, Clausi, Leone & Spiridonov. 2023) comb. n. – Nature Reserve ‘Speleological Complex Villasmundo – S. Alfio’, Syracuse Province , Sicily; from the slug Milax nigricans , found in 7 further gastropod species .

• P. zhejiangensis ( Zhang & Liu, 2020) comb. n. – Ningbo, Zhejiang province, China; from the slug Meghimatium (= Philomycus ) bilineatum from a vegetable garden.