On the genus Lagenopolycystis Artois and Schockaert, 2000 (Platyhelminthes, Kalyptorhynchia, Polycystididae) Monnens, Marlies Schockaert, Ernest R. Diez, Yander L. Revis, Nathalie Janssen, Toon Jouk, Philippe E. H. Tessens, Bart Van Steenkiste, Niels W. L. Artois, Tom J. Zootaxa 2025 2025-07-04 5659 3 357 376 3RWS5 (Brunet, 1965) Artois & Schockaert, 2000 Artois & Schockaert 2000 Brunet 1965 [151,962,330,357] Polycystididae Lagenopolycystis Animalia Rhabdocoela 4 361 Platyhelminthes species peresi  ( Fig. 2)   Emended diagnosis after Brunet (1965). Species of  Lagenopolycystiswith a prostate stylet of 68–103 µm (x̄ = 86 µm, n = 21) curved over its whole length for almost 180° and with a rounded end; both ‘walls’ of the gutter are proximally ear-shaped with a highly thickened rim. The accessory stylet is 32–64 µm (x̄ = 46 µm, n = 21), slightly curved and attached between the middle to the proximal 1/3 of the wall of the prostate stylet. The tube of the ‘seminal receptacle’ is about 20 µm and slightly spiralling.   Distribution. FRANCE• Gulf of Marseille, Plateau des Chèvres, N43°12’11” E5°21’54”, sand and gravel under the influence of bottom currents or  Amphioxussand, patch surrounded by a very nearby seagrass bed, with organic input from Marseille’s sewage discharged nearby, 10 mdeep (Leg. Dr M. Brunet, May–June 1964) (  TYPELOCALITY); Gulf of Marseille, between Île Plane and Île Riou, N43°11’09” E5°22’48”, same sediment typeon a rocky substrate, but with less organic material and much finer shell debris, 20 mdeep (Leg. Dr M. Brunet, May–June 1964).  Cerbère, Cap Peyrefite, N42°27’24” E3°10’15”, sand bottom alongside rock ledge, medium to coarse sand mixed with some shell grit,  20 mdeep (  14 July 2013); Peyrefite Bay, N42°27’37” E3°09’34”, in the middle of the bay, sand bank between seagrass beds, clean fine sand,  6–7 mdeep (  16 September 2019); Cerbère, ‘ Les Chambres’, N42°26’29” E3°10’22”, close to rocks in front of a cave, clean, coarse-grained sand mixed with fine gravel,  4 mdeep (  15 July 2007); same locality, N42°26’30” E3°10’20”, sand area between rocks, coarse sand mixed with gravel, shell grit, and debris of seagrass leaves,  5–6 mdeep (  25 July 2014); same locality, N42°26’30” E3°10’21”, sand area between rocks, coarse sand mixed with gravel,  5–6 mdeep (  16 July 2015); same locality, N42°26’31” E3°10’20”, past the coastal rock zone, clean fine sand,  17 mdeep (  2 August 2015); same locality, N42°26’33” E3°10’21”, past the coastal rock zone, clean fine sand mixed with some shell grit,  22 mdeep (  11 July 2023); Cerbère, Terrimbo, Les Aloés, N42°27’11” E3°09’43”, in front of the jetty, approximately  50 mseawards, fine-grained sand with some silt,  5 mdeep (  11 July 2007); same locality, N42°27’11” E3°09’43”at foot of rock forming a little island on the left side of the jetty, clean coarse sand mixed with gravel,  5 mdeep (  19 July 2012); same locality, N42°27’09” E3°09’48”, in front of jetty, past the coastal rock zone, clean fine sand,  9 mdeep (  5 August 2014); same locality, N42°27’12” E3°09’42”, at foot of rock forming a little island on the left side of the jetty, medium sand to fine gravel with some larger stones and debris of sea grass,  5–6 mdeep (  26 August 2016); Cerbère, small bay just outside the harbour, N42°26’28” E3°10’13”, fine sand mixed with some shell grit and some silt,  12 mdeep (  6 September 2024).  FRANCE, CORSICA • Bay of Calvi, western part of the bay in front of  Pointe de la Revellata, N42°35’04” E8°43’34”, sand from  35 mdeep ( Leg. Dr P. Martens,  12 April 1984). ADRIATIC SEA •  Amphioxussand at an unspecified locality (Dr T. Karling in Brunet, 1965).  ITALY, SARDINIA• Alghero, Calabonabeach, in front of bar Quintilionext to Hotel Calabona, N40°32’39” E8°19’13”, algae on rocks in small bay (  28 March 2010); Punta Negra, algae from rocks on a small beach sheltered from the sun (  19 August 1994); same locality, sand from gully, 30 cmdeep (  22 August 1994); same locality, algae on rocks near small jetty (  20 June 2007).  SPAIN• Portbou, small rock island just south of the harbour, N42°25’29” E3°10’17”, fine sand mixed with some shell grit and some silt,  22 mdeep (  19 July 2021).   Material examined. Twenty--six whole-mounted specimens on 25 slides, including four specimensfrom the SMNHcollections that were part of the material of the original description [ SMNHnr. 52945and 54926(with two specimens)– 54927], the others deposited in the collections of the UHasselt ( HU XXIII. 2.23– HU XXIII. 2.44).Five of those were in too bad shape to be measured. Five serially sectioned specimens, including the holotype( SMNHTypenr. 3044) and paratype( SMNH-Typenr. 5913), the other threedeposited in the collections of the Uhasselt ( HU XXIII .2.45– HU XXIII. 2.47).   Additional remarks. Brunet (1965)mentions a relative proboscis length of 1/4 of the body length, but in our specimens the length was almost about 1/5 of the body length. The morphology of the stylets of the newly collected specimens conforms to the original description by Brunet (1965). The robust prostate stylet, curved over its whole length, and with its ‘earlike’ proximal ends of the gutter, makes this species easy to recognise and distinguishes it from the other species of  Lagenopolycystis(see additional remarks on  L. azorensis  sp. nov.and  L. poena  sp. nov.). The record of  L. peresifrom Swedenis highly questionable: Brunet (1965)cited this record based on a photograph provided by Dr T. Karling. However, we have a whole mount in our collection labelled  L. peresi, collected in the Skagerrak by Karling, which is, in fact,  L. poena  sp. nov.Details regarding the locality on the label can be found under that species (see further). Thus, Brunet’s (1965)record of  L. peresifrom Swedenshould rather be attributed to  L. poena  sp. nov. 5209835318 SMNH 4 361 52945, 54926, 54927 4 holotype 5209835328 [384,1380,1807,1833] HU XXIII 4 361 2.23-2.44 1 5209835330 SMNHType 4 361 3044 1 holotype 5209835301 [319,735,1878,1905] SMNH-Type 4 361 5913 1 paratype 5209835329 HU XXIII 4 361 2.45-2.47 3