taxonID	type	description	language	source
98575F6FFFA4FFA9FF39FF684872EA82.taxon	description	General description of the taxon Lagenopolycystis Artois and Schockaert, 2000 (= Lagenorhynchus Brunet, 1965) (Fig. 1) Species of Lagenopolycystis are relatively small, measuring approximately 0.8 – 1.5 mm in size. Specimens are mostly transparent, with the anterior end often slightly orange-tinted. All species have relatively big eyes. The pharynx is of the normal polycystidid construction (Meixner, 1925) and is positioned a little anterior to the body middle (Fig. 1 A – C). The proboscis was described in detail by Brunet (1965), who mentioned some anatomical peculiarities compared to other polycystidids. However, our observations show that its anatomy is almost identical to that of species of Typhlopolycystis (see Brunet 1965; Schockaert et al. 2019) and, by extension, that of other representatives of Typhlopolycystidinae, e. g. Myobulla Artois & Schockaert, 2000 (for a detailed description and illustration, see Artois & Schockaert 2000). It is about 1 / 4 – 1 / 5 of the body length, with the cone retractors parallel to each other and a relatively thick inner circular muscle layer. The proboscis is a slender and elongate organ, with a pointed foreend and a very small apex. As in all typhlopolycystidinids, there are four pairs of proboscis retractors, one pair of integument retractors, and two pairs of strong dilatators on the proboscis cavity. The gonads are unpaired and (mostly) positioned at the left side of the body. Vitellaria can be paired or unpaired. The genital pore is at about 80 %; the genital atrium receives the uterus anteriorly, the male atrium from above and the female duct from behind. As in all members of Typhlopolycystidinae, the female atrial organs (Figs 1 C – F) consist of a short, moderately muscular female duct (type I) that receives the resorbing terminal bursa from behind and the ovo-vitelloduct anteriorly. Next to the entrance of the ovo-vitelloduct, there is a small sclerotised tube (tsr in Fig. 1), with a strong sphincter at its base. Such a sclerotised tube is also present in species of Limipolycystis, which exhibit an identical construction of the female atrial organs, apart from the fact that in species of Limipolycystis, this tube ends in the proximal part of the oviduct, while in species of Lagenopolycystis, it ends freely in the parenchyma (see Artois et al., 2012). This tube is usually very difficult or impossible to observe in live as well as in whole-mounted specimens. Often, sperm can be seen converging in the direction of this tube (Figs 1 E – F). Brunet (1965) initially interpreted the robust sphincter at the base of the tube as a closure for the bursa, inadvertently overlooking the presence of the tube itself. The function of the tube remains enigmatic, and it may serve as an insemination duct, or it could be involved in the evacuation of excess sperm to the parenchyma or intestine. In species of Typhlopolycystis, Brunetorhynchus, and Sabulirhynchus, a pear-shaped muscular ‘ seminal receptacle’ occurs instead of this sclerotised tube. Given the fact that Artois and Schockaert (2005) considered the tube to be homologous with the seminal receptacle, we will continue to refer to the sclerotized tube as the “ sclerotized tube of the seminal receptacle ”, expressing this hypothesis of homology. The male atrial organs are very similar to those in species of Typhlopolycystis (Figs 1 C and G). The hard parts of the copulatory organ (Figs 1 G – I) consist of a gutter-like main stylet (prostate stylet) that receives the prostate glands and the seminal duct (stylet and prostate glands type III); and an accessory stylet that receives the duct of the accessory secretion (accessory stylet and accessory vesicle type II). The prostate stylet is curved, with its concave side forming the ‘ closed side’ of the curve. In several species, this side is noticeably thickened. The tubiform and needle-like accessory stylet emerges from the left ‘ wall’ of the gutter (the stylet seen from its concave side) and passes along the right side towards the concave side of the main stylet. In some species, such as L. mutabilis sp. nov., the accessory stylet can be very small (Fig. 7), while in others, such as L. conglobata sp. nov., it can be nearly as long as the main stylet (Fig. 6). In most species of Typhlopolycystis, the accessory stylet is attached to the main stylet by a ring, and in species of the ‘ rubra group’, this ring is very narrow, and the accessory stylet is located next to, but not attached to, the main stylet (see Schockaert et al., 2019). Therefore, the difference with the construction of the hard parts of the copulatory organ of the species of Lagenopolycystis is not always clear. The presence of a sperm-filled seminal receptacle in species of Typhlopolycystis or a sclerotised tube in species of Lagenopolycystis near the ovary remains a good distinctive character for both genera. As mentioned before, the tube is often not visible in species of Lagenopolycystis, but the seminal receptacle in species of Typhlopolycystis is evident, especially in live specimens. Taxonomic account	en	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. (2025): On the genus Lagenopolycystis Artois and Schockaert, 2000 (Platyhelminthes, Kalyptorhynchia, Polycystididae). Zootaxa 5659 (3): 357-376, DOI: 10.11646/zootaxa.5659.3.3, URL: https://doi.org/10.11646/zootaxa.5659.3.3
98575F6FFFA4FFA9FF39FF684872EA82.taxon	diagnosis	Emended diagnosis after Brunet (1965). Species of Typhlopolycystidinae with a proboscis of 1 / 5 to 1 / 4 of the body length and with eyes. Gonads unpaired. Copulatory organ with prostate vesicle type III and accessory vesicle type II, a gutter-like prostate stylet type III, and a tubiform accessory stylet type II, the latter attached to one of the walls of the prostate stylet. With a sclerotised tubiform appendage (‘ seminal receptacle’) at the entrance of the oviduct.	en	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. (2025): On the genus Lagenopolycystis Artois and Schockaert, 2000 (Platyhelminthes, Kalyptorhynchia, Polycystididae). Zootaxa 5659 (3): 357-376, DOI: 10.11646/zootaxa.5659.3.3, URL: https://doi.org/10.11646/zootaxa.5659.3.3
98575F6FFFA4FFA9FF39FF684872EA82.taxon	type_taxon	Type species. Lagenopolycystis peresi (Brunet, 1965) Artois & Schockaert, 2000 by original monotypy.	en	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. (2025): On the genus Lagenopolycystis Artois and Schockaert, 2000 (Platyhelminthes, Kalyptorhynchia, Polycystididae). Zootaxa 5659 (3): 357-376, DOI: 10.11646/zootaxa.5659.3.3, URL: https://doi.org/10.11646/zootaxa.5659.3.3
98575F6FFFA2FFABFF39FEB54C50EB8E.taxon	description	(Fig. 2)	en	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. (2025): On the genus Lagenopolycystis Artois and Schockaert, 2000 (Platyhelminthes, Kalyptorhynchia, Polycystididae). Zootaxa 5659 (3): 357-376, DOI: 10.11646/zootaxa.5659.3.3, URL: https://doi.org/10.11646/zootaxa.5659.3.3
98575F6FFFA2FFABFF39FEB54C50EB8E.taxon	diagnosis	Emended diagnosis after Brunet (1965). Species of Lagenopolycystis with a prostate stylet of 68 – 103 µm (x ̄ = 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 (x ̄ = 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.	en	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. (2025): On the genus Lagenopolycystis Artois and Schockaert, 2000 (Platyhelminthes, Kalyptorhynchia, Polycystididae). Zootaxa 5659 (3): 357-376, DOI: 10.11646/zootaxa.5659.3.3, URL: https://doi.org/10.11646/zootaxa.5659.3.3
98575F6FFFA2FFABFF39FEB54C50EB8E.taxon	distribution	Distribution. FRANCE • Gulf of Marseille, Plateau des Chèvres, N 43 ° 12 ’ 11 ” E 5 ° 21 ’ 54 ”, sand and gravel under the influence of bottom currents or Amphioxus sand, patch surrounded by a very nearby seagrass bed, with organic input from Marseille’s sewage discharged nearby, 10 m deep (Leg. Dr M. Brunet, May – June 1964) (TYPE LOCALITY); Gulf of Marseille, between Île Plane and Île Riou, N 43 ° 11 ’ 09 ” E 5 ° 22 ’ 48 ”, same sediment type on a rocky substrate, but with less organic material and much finer shell debris, 20 m deep (Leg. Dr M. Brunet, May – June 1964). Cerbère, Cap Peyrefite, N 42 ° 27 ’ 24 ” E 3 ° 10 ’ 15 ”, sand bottom alongside rock ledge, medium to coarse sand mixed with some shell grit, 20 m deep (14 July 2013); Peyrefite Bay, N 42 ° 27 ’ 37 ” E 3 ° 09 ’ 34 ”, in the middle of the bay, sand bank between seagrass beds, clean fine sand, 6 – 7 m deep (16 September 2019); Cerbère, ‘ Les Chambres’, N 42 ° 26 ’ 29 ” E 3 ° 10 ’ 22 ”, close to rocks in front of a cave, clean, coarse-grained sand mixed with fine gravel, 4 m deep (15 July 2007); same locality, N 42 ° 26 ’ 30 ” E 3 ° 10 ’ 20 ”, sand area between rocks, coarse sand mixed with gravel, shell grit, and debris of seagrass leaves, 5 – 6 m deep (25 July 2014); same locality, N 42 ° 26 ’ 30 ” E 3 ° 10 ’ 21 ”, sand area between rocks, coarse sand mixed with gravel, 5 – 6 m deep (16 July 2015); same locality, N 42 ° 26 ’ 31 ” E 3 ° 10 ’ 20 ”, past the coastal rock zone, clean fine sand, 17 m deep (2 August 2015); same locality, N 42 ° 26 ’ 33 ” E 3 ° 10 ’ 21 ”, past the coastal rock zone, clean fine sand mixed with some shell grit, 22 m deep (11 July 2023); Cerbère, Terrimbo, Les Aloés, N 42 ° 27 ’ 11 ” E 3 ° 09 ’ 43 ”, in front of the jetty, approximately 50 m seawards, fine-grained sand with some silt, 5 m deep (11 July 2007); same locality, N 42 ° 27 ’ 11 ” E 3 ° 09 ’ 43 ” at foot of rock forming a little island on the left side of the jetty, clean coarse sand mixed with gravel, 5 m deep (19 July 2012); same locality, N 42 ° 27 ’ 09 ” E 3 ° 09 ’ 48 ”, in front of jetty, past the coastal rock zone, clean fine sand, 9 m deep (5 August 2014); same locality, N 42 ° 27 ’ 12 ” E 3 ° 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 m deep (26 August 2016); Cerbère, small bay just outside the harbour, N 42 ° 26 ’ 28 ” E 3 ° 10 ’ 13 ”, fine sand mixed with some shell grit and some silt, 12 m deep (6 September 2024). FRANCE, CORSICA • Bay of Calvi, western part of the bay in front of Pointe de la Revellata, N 42 ° 35 ’ 04 ” E 8 ° 43 ’ 34 ”, sand from 35 m deep (Leg. Dr P. Martens, 12 April 1984). ADRIATIC SEA • Amphioxus sand at an unspecified locality (Dr T. Karling in Brunet, 1965). ITALY, SARDINIA • Alghero, Calabona beach, in front of bar Quintilio next to Hotel Calabona, N 40 ° 32 ’ 39 ” E 8 ° 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 cm deep (22 August 1994); same locality, algae on rocks near small jetty (20 June 2007). SPAIN • Portbou, small rock island just south of the harbour, N 42 ° 25 ’ 29 ” E 3 ° 10 ’ 17 ”, fine sand mixed with some shell grit and some silt, 22 m deep (19 July 2021).	en	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. (2025): On the genus Lagenopolycystis Artois and Schockaert, 2000 (Platyhelminthes, Kalyptorhynchia, Polycystididae). Zootaxa 5659 (3): 357-376, DOI: 10.11646/zootaxa.5659.3.3, URL: https://doi.org/10.11646/zootaxa.5659.3.3
98575F6FFFA2FFABFF39FEB54C50EB8E.taxon	materials_examined	Material examined. Twenty- - six whole-mounted specimens on 25 slides, including four specimens from the SMNH collections that were part of the material of the original description [SMNH nr. 52945 and 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 (SMNHType nr. 3044) and paratype (SMNH-Type nr. 5913), the other three deposited in the collections of the Uhasselt (HU XXIII. 2.45 – HU XXIII. 2.47).	en	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. (2025): On the genus Lagenopolycystis Artois and Schockaert, 2000 (Platyhelminthes, Kalyptorhynchia, Polycystididae). Zootaxa 5659 (3): 357-376, DOI: 10.11646/zootaxa.5659.3.3, URL: https://doi.org/10.11646/zootaxa.5659.3.3
98575F6FFFA2FFABFF39FEB54C50EB8E.taxon	discussion	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. peresi from Sweden is 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. peresi from Sweden should rather be attributed to L. poena sp. nov.	en	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. (2025): On the genus Lagenopolycystis Artois and Schockaert, 2000 (Platyhelminthes, Kalyptorhynchia, Polycystididae). Zootaxa 5659 (3): 357-376, DOI: 10.11646/zootaxa.5659.3.3, URL: https://doi.org/10.11646/zootaxa.5659.3.3
98575F6FFFA0FFAAFF39FDB94E79EEBE.taxon	description	urn: lsid: zoobank. org: act: 310 DD 83 C- 436 F- 4 DCC- 8829 - A 828 BB 1 C 448 B (Fig. 3)	en	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. (2025): On the genus Lagenopolycystis Artois and Schockaert, 2000 (Platyhelminthes, Kalyptorhynchia, Polycystididae). Zootaxa 5659 (3): 357-376, DOI: 10.11646/zootaxa.5659.3.3, URL: https://doi.org/10.11646/zootaxa.5659.3.3
98575F6FFFA0FFAAFF39FDB94E79EEBE.taxon	diagnosis	Diagnosis. Species of Lagenopolycystis with a proboscis up to 1 / 4 of the body length. Prostate stylet of 68 – 88 µm (x ̄ = 82 µm, n = 6), very slightly curved and with a blunt terminal end; the proximal part of the stylet is perpendicular to the terminal part. The accessory stylet is attached to the main stylet at the outer corner of the 90 ° angle. It is 45 – 71 µm (x ̄ = 59 µm, n = 6), sharp ending, slightly curved at its end. The tube of the ‘ seminal receptacle’ is about 15 µm, straight and robust.	en	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. (2025): On the genus Lagenopolycystis Artois and Schockaert, 2000 (Platyhelminthes, Kalyptorhynchia, Polycystididae). Zootaxa 5659 (3): 357-376, DOI: 10.11646/zootaxa.5659.3.3, URL: https://doi.org/10.11646/zootaxa.5659.3.3
98575F6FFFA0FFAAFF39FDB94E79EEBE.taxon	distribution	Distribution. FRANCE • Bay of Marseille, Plateau des Chèvres, Amphioxus sand, 8 – 10 m deep (Leg. M. Brunet, 3 February 1966) (TYPE LOCALITY); Cerbère, ‘ Les Chambres’, beneath rock of small cave, N 42 ° 26 ’ 29 ” E 3 ° 10 ’ 22 ”, clean, coarse-grained sand and fine gravel, 2 – 3 m deep (1 August 2008); same locality, N 42 ° 26 ’ 29 ” E 3 ° 10 ’ 21 ”, sand area between rocks, coarse sand mixed with shell grit, 5 – 6 m deep (4 August 2014). ITALY, SARDINIA • Cavaliere, Budelli, N 41 ° 17 ’ 30 ” E 9 ° 20 ’ 52 ”, medium to fin-grained, rather clean sand, 35 m deep (7 September 2010). SPAIN • Portbou, l’Ocell, N 42 ° 25 ’ 59 ” E 3 ° 10 ’ 27 ”, clean medium sand mixed with shell grit, 18 m deep (20 July 2023). SPAIN, LANZAROTE • Punta Jameos del Agua, N 29 ° 9 ’ 25 ” W 13 ° 25 ’ 38 ”, coarse sand, 12 m deep, salinity 35 ‰ (15 October 2011).	en	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. (2025): On the genus Lagenopolycystis Artois and Schockaert, 2000 (Platyhelminthes, Kalyptorhynchia, Polycystididae). Zootaxa 5659 (3): 357-376, DOI: 10.11646/zootaxa.5659.3.3, URL: https://doi.org/10.11646/zootaxa.5659.3.3
98575F6FFFA0FFAAFF39FDB94E79EEBE.taxon	materials_examined	Material examined. Live observations and photographs. Eight whole mounts, including the holotype (FMNH http: // id. luomus. fi / KV. 543). One specimen in the collections of SMNH (SMNH- 54569), the rest deposited as reference material in the collections of Hasselt University (HU XXIII. 2.48 – HU XXIII. 3.03). Two of these are outliers because of the dimensions of the hard parts (see “ Additional remarks ”). Two sectioned specimens (HU XXIII. 3.04 – HU XXIII. 3.05).	en	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. (2025): On the genus Lagenopolycystis Artois and Schockaert, 2000 (Platyhelminthes, Kalyptorhynchia, Polycystididae). Zootaxa 5659 (3): 357-376, DOI: 10.11646/zootaxa.5659.3.3, URL: https://doi.org/10.11646/zootaxa.5659.3.3
98575F6FFFA0FFAAFF39FDB94E79EEBE.taxon	etymology	Etymology. According to the notes of Dr M. Brunet, the accessory stylet articulates with the main stylet in the living animal. Articulatus (Lat.): articulated.	en	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. (2025): On the genus Lagenopolycystis Artois and Schockaert, 2000 (Platyhelminthes, Kalyptorhynchia, Polycystididae). Zootaxa 5659 (3): 357-376, DOI: 10.11646/zootaxa.5659.3.3, URL: https://doi.org/10.11646/zootaxa.5659.3.3
98575F6FFFA0FFAAFF39FDB94E79EEBE.taxon	discussion	Additional remarks. The proboscis is proportionally larger than that of congeneric species (except for the specimens of L. peresi collected by Dr M. Brunet; see Brunet, 1965), constituting approximately 1 / 4 of the total body length. Two specimens from the Mediterranean region are considered outliers because of the size of the sclerotised parts in the reproductive system: the copulatory organ of the first specimen (from Portbou; HU XXIII. 3.02) is notably smaller, with a prostate stylet measuring 59 µm and an accessory stylet measuring 42 µm. The other specimen’s copulatory organ (from Cerbère; HU XXIII. 3.03) is notably larger, with a prostate stylet of 115 µm and an accessory stylet of 64 µm. For now, these outliers are excluded from the diagnosis listed above. However, it appears that additional sampling is needed to fully capture the intraspecific variation in this species. Although L. articulata sp. nov. superficially resembles L. peresi, L. azorensis sp. nov., L. canariensis sp. nov., and L. poena sp. nov., it can be distinguished from these four species by the fact that in L. articulata sp. nov. the proximal and the distal part of the stylet form an abrupt, 90 ° curve. In the four other species mentioned, the stylet does not show such an abrupt angle, but is more evenly curved.	en	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. (2025): On the genus Lagenopolycystis Artois and Schockaert, 2000 (Platyhelminthes, Kalyptorhynchia, Polycystididae). Zootaxa 5659 (3): 357-376, DOI: 10.11646/zootaxa.5659.3.3, URL: https://doi.org/10.11646/zootaxa.5659.3.3
98575F6FFFA1FFA4FF39FAE94C3AE81A.taxon	description	urn: lsid: zoobank. org: act: 7943 A 224 - 0 AB 3 - 4422 - B 0 B 2 - C 9127 B 983 A 8 F (Fig. 4)	en	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. (2025): On the genus Lagenopolycystis Artois and Schockaert, 2000 (Platyhelminthes, Kalyptorhynchia, Polycystididae). Zootaxa 5659 (3): 357-376, DOI: 10.11646/zootaxa.5659.3.3, URL: https://doi.org/10.11646/zootaxa.5659.3.3
98575F6FFFA1FFA4FF39FAE94C3AE81A.taxon	diagnosis	Diagnosis. Species of Lagenopolycystis with a prostate stylet of 71 – 105 µm (x ̄ = 89 µm, n = 15), curved at about 90 ° with a blunt terminal end; the proximal part of the stylet has two prominent, ear-shaped rims at both ends of the gutter. The accessory stylet attaches to the main stylet just below these thickened rims, at about 1 / 3 of the proximal end of the stylet. It measures 44 – 64 µm (x ̄ = 57 µm, n = 15), is slender and sharp-ended, and is generally straight, though a slightly bent tip was observed in most specimens. The structure of the ‘ seminal receptacle tube’ is unknown.	en	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. (2025): On the genus Lagenopolycystis Artois and Schockaert, 2000 (Platyhelminthes, Kalyptorhynchia, Polycystididae). Zootaxa 5659 (3): 357-376, DOI: 10.11646/zootaxa.5659.3.3, URL: https://doi.org/10.11646/zootaxa.5659.3.3
98575F6FFFA1FFA4FF39FAE94C3AE81A.taxon	distribution	Distribution. PORTUGAL, AZORES, SÃO MIGUEL • Maia, N 37 ° 50 ’ 03 ” W 25 ° 23 ’ 8 ”, sand from between rocks, 0.5 – 2 m deep (20 July 2019) (TYPE LOCALITY). ITALY, SARDINIA • Cala Sant’ Andrea, N 41 ° 00 ’ 48 ” E 8 ° 14 ’ 56 ”, 5 to 6 m deep (27 September 2014). FRANCE • Banyuls-sur-Mer, Île Grosse, ‘ La Faille’, N 42 ° 28 ’ 57 ” E 3 ° 08 ’ 16 ”, clean fine sand, 12 m deep (6 August 2007); Banyuls-sur-Mer, ‘ l’Herbier’, 20 – 30 m left of end of pipes, N 42 ° 28 ’ 56 ” E 3 ° 08 ’ 09 ”, fine to medium sand with some silt, 10 m deep (2 November 2007); Cerbère, Peyrefite Bay, south side of bay, N 42 ° 27 ’ 35 ” E 3 ° 09 ’ 34 ”, sand area between sea grass beds and rocks, clean fine sand, 7 m deep (13 July 2007); same locality, south side of bay, N 42 ° 27 ’ 35 ” E 3 ° 09 ’ 28 ”, sand mixed with some gravel, 3 m deep (12 July 2020); Cerbère, ‘ Les Chambres’, N 42 ° 26 ’ 28 ” E 3 ° 10 ’ 16 ”, sand area between rocks, medium to coarse sand, 2 – 3 m deep (16 July 2013); same locality, N 42 ° 26 ’ 30 ” E 3 ° 10 ’ 21 ”, sand area between rocks, coarse sand mixed with gravel, 5 – 6 m deep (16 July 2015); Cerbère, Terrimbo, Les Aloès, N 42 ° 27 ’ 12 ” E 3 ° 09 ’ 42 ”, at foot of rock forming a little island on the left side of the jetty, medium sand mixed with some gravel and debris of sea grass leaves, 6 m deep (26 August 2016); same locality, small rocky islands just south of municipal camping, N 42 ° 27 ’ 13 ” E 3 ° 09 ’ 52 ”, fine sand with some silt, 15 m deep (18 May 2022). SPAIN • Portbou, l’Ocell, N 42 ° 25 ’ 59 ” E 3 ° 10 ’ 28 ”, clean gravel mixed with shell grit, 20 m deep (29 May 2023); same locality, N 42 ° 25 ’ 59 ” E 3 ° 10 ’ 28 ”, clean medium sand, 18 m deep (16 July 2023).	en	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. (2025): On the genus Lagenopolycystis Artois and Schockaert, 2000 (Platyhelminthes, Kalyptorhynchia, Polycystididae). Zootaxa 5659 (3): 357-376, DOI: 10.11646/zootaxa.5659.3.3, URL: https://doi.org/10.11646/zootaxa.5659.3.3
98575F6FFFA1FFA4FF39FAE94C3AE81A.taxon	materials_examined	Material examined. Live observations and photographs. Fifteen whole mounts, one of which designated holotype (FMNH http: // id. luomus. fi / KV. 544), the rest deposited as reference material in the collections of Hasselt University (HU XXIII. 3.06 – HU XXIII. 3.19).	en	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. (2025): On the genus Lagenopolycystis Artois and Schockaert, 2000 (Platyhelminthes, Kalyptorhynchia, Polycystididae). Zootaxa 5659 (3): 357-376, DOI: 10.11646/zootaxa.5659.3.3, URL: https://doi.org/10.11646/zootaxa.5659.3.3
98575F6FFFA1FFA4FF39FAE94C3AE81A.taxon	etymology	Etymology. The species name refers to the type locality on the Azores.	en	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. (2025): On the genus Lagenopolycystis Artois and Schockaert, 2000 (Platyhelminthes, Kalyptorhynchia, Polycystididae). Zootaxa 5659 (3): 357-376, DOI: 10.11646/zootaxa.5659.3.3, URL: https://doi.org/10.11646/zootaxa.5659.3.3
98575F6FFFA1FFA4FF39FAE94C3AE81A.taxon	discussion	Additional remarks. The sclerotised parts of L. azorensis sp. nov. and L. peresi are similar but can be distinguished by several features. The prostate stylet of L. azorensis sp. nov. is bent more or less over 90 °, whereas that of L. peresi curves along its entire length to almost 180 °. The thickened proximal rims of this stylet are ear-shaped in both species; however, in L. peresi these rims are straight and asymmetrical, one being larger than the other, whereas they have a more rounded and symmetrical appearance in L. azorensis sp. nov. Moreover, the accessory stylet in L. azorensis sp. nov. is more slender than in L. peresi, giving the copulatory organ an overall more ‘ elegant’ appearance.	en	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. (2025): On the genus Lagenopolycystis Artois and Schockaert, 2000 (Platyhelminthes, Kalyptorhynchia, Polycystididae). Zootaxa 5659 (3): 357-376, DOI: 10.11646/zootaxa.5659.3.3, URL: https://doi.org/10.11646/zootaxa.5659.3.3
98575F6FFFAFFFA4FF39FD4D4873EDF4.taxon	description	urn: lsid: zoobank. org: act: E 2226669 - 7 A 0 D- 446 B- 968 F- 4495 B 997 CA 15 (Fig. 5)	en	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. (2025): On the genus Lagenopolycystis Artois and Schockaert, 2000 (Platyhelminthes, Kalyptorhynchia, Polycystididae). Zootaxa 5659 (3): 357-376, DOI: 10.11646/zootaxa.5659.3.3, URL: https://doi.org/10.11646/zootaxa.5659.3.3
98575F6FFFAFFFA4FF39FD4D4873EDF4.taxon	diagnosis	Diagnosis. Species of Lagenopolycystis with a prostate stylet of 46 – 65 µm (x ̄ = 58 µm, n = 17), regularly curved over its whole length and with a blunt terminal end; the terminal part is perpendicular to the proximal part of which the rims are only slightly thickened. The accessory stylet is 25 – 49 µm (x ̄ = 38 µm, n = 17), straight and very sharp ending; it is attached at the very proximal end of the main stylet. The tube of the ‘ seminal receptacle’ is unknown.	en	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. (2025): On the genus Lagenopolycystis Artois and Schockaert, 2000 (Platyhelminthes, Kalyptorhynchia, Polycystididae). Zootaxa 5659 (3): 357-376, DOI: 10.11646/zootaxa.5659.3.3, URL: https://doi.org/10.11646/zootaxa.5659.3.3
98575F6FFFAFFFA4FF39FD4D4873EDF4.taxon	distribution	Distribution. SPAIN, LANZAROTE • Mala, in front of ‘ Cuevita de Mala’ N 29 ° 05 ’ 01 ” W 13 ° 26 ’ 59 ”, sand patch under loose macroalgae, coarse shell gravel, very clean, calcareous sand with basalt, 12 m deep (8 October 2011). (TYPE LOCALITY). Playa Órzola, near the open connection with the sea at high tide, N 29 ° 13 ’ 08 ” W 13 ° 26 ’ 28 ”, algae from the rocks (12 October 2011). Órzola, beach approximately 700 m south of Órzola, N 29 ° 13 ’ 20 ” W 13 ° 26 ’ 58 ”, pool connected to the sea but closed off by lava rocks; sheltered with no significant waves apart from tide and current, coarse sand with scattered lava rocks, sample taken at 40 – 50 cm depth, approximately 50 – 60 m from the shore (7 October 2011); same locality, medium coarse sand with holes from digging animals, sample taken at low tide just below the waterline (6 October 2011); same locality, N 29 ° 12 ’ 59 ” W 13 ° 26 ’ 32 ”, deeper area beyond the rocks, coarse sand (14 October 2011). Punta Jameos del Agua, offshore, N 29 ° 09 ’ 25 ” W 13 ° 25 ’ 38 ”, medium, clean sand with Caulerpa sp., 38 m deep (15 October 2011); same locality, 12 m deep, coarse sand (15 October 2011). Mala, N 29 ° 05 ’ 01 ” W 13 ° 26 ’ 59 ”, coarse volcanic and biogenic (CaCO ₃) sand among rocks, 4 to 6 m deep (13 October 2011); same locality, medium coarse calcareous sand from a very steep slope, close to black coral, 48 m deep (8 October 2011). Salinity in all localities on Lanzarote is 35 ‰. PORTUGAL, AZORES, SÃO MIGUEL • Ribeirinha, N 37 ° 50 ’ 11 ” W 25 ° 29 ’ 01 ”, lots of large boulders with coarse sand around the bottom (22 July 2019).	en	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. (2025): On the genus Lagenopolycystis Artois and Schockaert, 2000 (Platyhelminthes, Kalyptorhynchia, Polycystididae). Zootaxa 5659 (3): 357-376, DOI: 10.11646/zootaxa.5659.3.3, URL: https://doi.org/10.11646/zootaxa.5659.3.3
98575F6FFFAFFFA4FF39FD4D4873EDF4.taxon	materials_examined	Material examined. Live observations and photographs. Nineteen whole mounts, one of which designated holotype (FMNH http: // id. luomus. fi / KV. 545), and the others reference material (HU XXIII. 3.20 – HU XXIII. 3.37). Two of them could not be measured (HU numbers XXIII. 3.21 & 22). Five serially sectioned specimens, the obliquely sectioned one on two slides. (HU XXIII. 3.38 – HU XXIII. 3.43).	en	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. (2025): On the genus Lagenopolycystis Artois and Schockaert, 2000 (Platyhelminthes, Kalyptorhynchia, Polycystididae). Zootaxa 5659 (3): 357-376, DOI: 10.11646/zootaxa.5659.3.3, URL: https://doi.org/10.11646/zootaxa.5659.3.3
98575F6FFFAFFFA4FF39FD4D4873EDF4.taxon	etymology	Etymology. The species name refers to the type locality on the Canary Islands.	en	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. (2025): On the genus Lagenopolycystis Artois and Schockaert, 2000 (Platyhelminthes, Kalyptorhynchia, Polycystididae). Zootaxa 5659 (3): 357-376, DOI: 10.11646/zootaxa.5659.3.3, URL: https://doi.org/10.11646/zootaxa.5659.3.3
98575F6FFFAFFFA4FF39FD4D4873EDF4.taxon	discussion	Additional remarks. As in L. peresi and L. poena sp. nov., the prostate stylet of L. canariensis sp. nov. is evenly curved, in contrast to the abrupt 90 ° angle between proximal and distal part observed in L. articulata sp. nov. Lagenopolycystis canariensis sp. nov. stands unique among these species because of the fact that the accessory stylet is attached to the most proximal end of the prostate stylet, which makes identification straightforward.	en	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. (2025): On the genus Lagenopolycystis Artois and Schockaert, 2000 (Platyhelminthes, Kalyptorhynchia, Polycystididae). Zootaxa 5659 (3): 357-376, DOI: 10.11646/zootaxa.5659.3.3, URL: https://doi.org/10.11646/zootaxa.5659.3.3
98575F6FFFACFFA1FF39F97449DAEC72.taxon	description	urn: lsid: zoobank. org: act: 742 C 9 CE 4 - F 1 C 8 - 4 C 3 F-A 6 C 9 - BFC 379775466 (Fig. 6)	en	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. (2025): On the genus Lagenopolycystis Artois and Schockaert, 2000 (Platyhelminthes, Kalyptorhynchia, Polycystididae). Zootaxa 5659 (3): 357-376, DOI: 10.11646/zootaxa.5659.3.3, URL: https://doi.org/10.11646/zootaxa.5659.3.3
98575F6FFFACFFA1FF39F97449DAEC72.taxon	diagnosis	Diagnosis. Species of Lagenopolycystis with a robust prostate stylet of 71 – 130 µm (x ̄ = 100 µm, n = 31), evenly curved over its whole length and with a blunt terminal end. The accessory stylet, attached at the very proximal end of the main stylet, is 52 – 123 µm (x ̄ = 92 µm, n = 27), following the curve of the prostate stylet and closely stuck to it, giving the whole copulatory organ a conglobate aspect. The short straight tube of the ‘ seminal receptacle’ is 3 – 4 µm long.	en	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. (2025): On the genus Lagenopolycystis Artois and Schockaert, 2000 (Platyhelminthes, Kalyptorhynchia, Polycystididae). Zootaxa 5659 (3): 357-376, DOI: 10.11646/zootaxa.5659.3.3, URL: https://doi.org/10.11646/zootaxa.5659.3.3
98575F6FFFACFFA1FF39F97449DAEC72.taxon	distribution	Distribution. FRANCE • Bay of Marseille, Plateau des Chèvres, Amphioxus sand, 8 – 10 m deep (Leg. Dr M. Brunet, 3 February 1966) (TYPE LOCALITY) and near ‘ La Pierre Joseph’ at the isle of Plane, fine sand, 17 m deep (collected by Dr M. Brunet, 7 July 1970); Banyuls-sur-Mer, Ile Grosse, ‘ La Faille’, N 42 ° 28 ’ 57 ” E 3 ° 08 ’ 16 ”, clean, fine sand, 12 m deep (6 August 2007); Banyuls-sur-Mer, ‘ l’Herbier’, 20 – 30 m left of end of pipes, N 42 ° 28 ’ 56 ” E 3 ° 08 ’ 09 ”, fine to medium sand with some silt, 10 m deep (2 November 2007); Cerbère, Canadells Islands, N 42 ° 26 ’ 52 ” E 3 ° 10 ’ 23 ”, sand mixed with much shell grit, 30 m deep (12 July 2023); Cerbère, Cap Peyrefite, N 42 ° 27 ’ 24 ” E 3 ° 10 ’ 15 ”, sand bottom alongside rock ledge, medium to coarse sand mixed with some shell grit, 20 m deep (14 July 2013); same locality, N 42 ° 27 ’ 23 ” E 3 ° 10 ’ 10 ”, clean fine sand, 18 m deep (13 July 2014); same location, N 42 ° 27 ’ 25 ” E 3 ° 10 ’ 17 ”, sand bottom alongside rock ledge, fine sand with some silt and debris of seagrass leaves, 22 m deep (12 July 2024); Peyrefite Bay, In the middle of the bay, N 42 ° 27 ’ 37 ” E 3 ° 09 ’ 32 ”, sand bank between seagrass beds, medium to coarse sand on top of ripple mark, 5 m deep (13 September 2019); Cerbère, ‘ Les Chambres’, N 42 ° 26 ’ 31 ” E 3 ° 10 ’ 19 ”, sand area between seagrass beds, coarse sand mixed with some shell grit, 14 m deep (4 August 2014); same locality, N 42 ° 26 ’ 32 ” E 3 ° 10 ’ 20 ”, past the coastal rock zone, clean medium sand mixed with some fine shell grit, 19 m deep (27 May 2023); same locality, past the coastal rock zone, N 42 ° 26 ’ 33 ” E 3 ° 110 ’ 21 ”, clean medium sand mixed with some fine shell grit, 22 m deep (29 July 2024); Cerbère, Terrimbo, Les Aloès, in front of jetty, near railroad track, N 42 ° 27 ’ 11 ” E 3 ° 09 ’ 42 ”, fine gravel with some silt, 5 m deep (14 July 2011); same location, in front of jetty, past the coastal rock zone, N 42 ° 27 ’ 09 ” E 3 ° 09 ’ 47 ”, clean coarse sand mixed with some fine gravel, 8 m deep (8 September 2024); Cerbère, Terrimbo, middle of bay, N 42 ° 27 ’ 07 ” E 3 ° 09 ’ 59 ”, clean fine to medium sand on top of ripple mark, 20 m deep (31 July 2015); same locality, small rocky islands just south of municipal camping, N 42 ° 27 ’ 13 ” E 3 ° 09 ’ 55 ”, clean fine sand with some fine shell grit, 15 m deep and N 42 ° 27 ’ 13 ” E 3 ° 09 ’ 50 ”, fine sand with some silt, 15 m deep (18 May 2022); same locality, middle of bay, N 42 ° 27 ’ 07 ” E 3 ° 09 ’ 58 ”, fine sand mixed with some shell grit and silt, 19 m deep (9 September 2023); Cerbère, near harbour wall, N 42 ° 26 ’ 31 ” E 3 ° 10 ’ 04 ”, very fine sand with some silt, 3 m deep (11 September 2024). FRANCE, CORSICA • Bay of Calvi, western part of the bay in front of Pointe de la Revellata, N 42 ° 3 ’ 0 ” E 8 ° 4 ’ 3 ”, sand from 35 m deep (Leg. Dr P. Martens, 22 October 1982, 12 May and 25 November 1983). ITALY, SARDINIA • Punta Negra, sand with pebbles and a small amount of detritus, 30 cm deep (19 and 22 August 1994); Punta Tamburino, N 41 ° 0 ’ 1 ” E 8 ° 1 ’ 1 ”, channel among rocks, coarse gravel with silt, 29 m deep (29 September 2014). SPAIN • Portbou, l’Ocell, N 42 ° 25 ’ 58 ” E 3 ° 10 ’ 29 ”, clean medium sand mixed with much shell grit, 23 m deep (18 July 2011).	en	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. (2025): On the genus Lagenopolycystis Artois and Schockaert, 2000 (Platyhelminthes, Kalyptorhynchia, Polycystididae). Zootaxa 5659 (3): 357-376, DOI: 10.11646/zootaxa.5659.3.3, URL: https://doi.org/10.11646/zootaxa.5659.3.3
98575F6FFFACFFA1FF39F97449DAEC72.taxon	materials_examined	Material examined. Thirty-two whole mounts, one of which designated the holotype (FMNH http: // id. luomus. fi / KV. 546), one in the collections of SMNH (SMNH- 54570), and the rest deposited as reference material in the collections of Hasselt University (HU XXIII. 3.44 – HU XXIII. 4.23). The stylet of one specimen (HU XXIII. 3.49) and the accessory stylet of five specimens (HU XXIII. 3.49; XXII. 4.04, 12, 15, 16) could not be measured. Five serial sections (HU XXIII. 4.24 – HU XXIII. 4.28).	en	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. (2025): On the genus Lagenopolycystis Artois and Schockaert, 2000 (Platyhelminthes, Kalyptorhynchia, Polycystididae). Zootaxa 5659 (3): 357-376, DOI: 10.11646/zootaxa.5659.3.3, URL: https://doi.org/10.11646/zootaxa.5659.3.3
98575F6FFFACFFA1FF39F97449DAEC72.taxon	etymology	Etymology. The species name refers to the conglobate and compact aspect of the copulatory organ. Conglobatus (Lat.): pressed tightly together.	en	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. (2025): On the genus Lagenopolycystis Artois and Schockaert, 2000 (Platyhelminthes, Kalyptorhynchia, Polycystididae). Zootaxa 5659 (3): 357-376, DOI: 10.11646/zootaxa.5659.3.3, URL: https://doi.org/10.11646/zootaxa.5659.3.3
98575F6FFFACFFA1FF39F97449DAEC72.taxon	discussion	Additional remarks. Lagenopolycystis conglobata is the only species in which the accessory stylet follows the curve of the prostate stylet, lying tightly adjacent to it. This feature makes this species unmistakable.	en	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. (2025): On the genus Lagenopolycystis Artois and Schockaert, 2000 (Platyhelminthes, Kalyptorhynchia, Polycystididae). Zootaxa 5659 (3): 357-376, DOI: 10.11646/zootaxa.5659.3.3, URL: https://doi.org/10.11646/zootaxa.5659.3.3
98575F6FFFAAFFA0FF39F9A54902EDB4.taxon	description	urn: lsid: zoobank. org: act: 086 FF 139 - FB 29 - 46 EF-BEED- 5014 C 6 D 90 FD 4 (Fig. 7)	en	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. (2025): On the genus Lagenopolycystis Artois and Schockaert, 2000 (Platyhelminthes, Kalyptorhynchia, Polycystididae). Zootaxa 5659 (3): 357-376, DOI: 10.11646/zootaxa.5659.3.3, URL: https://doi.org/10.11646/zootaxa.5659.3.3
98575F6FFFAAFFA0FF39F9A54902EDB4.taxon	diagnosis	Diagnosis. Species of Lagenopolycystis with a prostate stylet of 100 – 134 µm (x ̄ = 123 µm, n = 8), curved over its whole length with a strong curl proximally and distally and a rounded end. The accessory stylet is 28 – 35 µm (x ̄ = 33 µm, n = 8) and attached at the very proximal end of the main stylet, apparently with a slightly variable shape. The tube of the ‘ seminal receptacle’ is unknown.	en	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. (2025): On the genus Lagenopolycystis Artois and Schockaert, 2000 (Platyhelminthes, Kalyptorhynchia, Polycystididae). Zootaxa 5659 (3): 357-376, DOI: 10.11646/zootaxa.5659.3.3, URL: https://doi.org/10.11646/zootaxa.5659.3.3
98575F6FFFAAFFA0FF39F9A54902EDB4.taxon	distribution	Distribution. KENYA • South of Mombasa, Tiwi, Tiwi Beach, S 4 ° 1 ’ 1 ” E 39 ° 3 ’ 5 ”, coarse sand and shell gravel from a tide pool near the reef front (TYPE LOCALITY) (6 October 1991). Mombasa, McKenzie Point on walking distance south of the Kenya Marine and Fisheries Research Institute, very fine sand and algae from a shallow tide pool just past the second obelisk (1 October 1991); same locality, S 4 ° 0 ’ 4 ” E 39 ° 4 ’ 2 ”, on seagrass and in relatively fine sediment from shallow tide pools (30 September 1991) and in coarse shell-gravel on a rock in the mid- and low littoral (27 September 1991).	en	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. (2025): On the genus Lagenopolycystis Artois and Schockaert, 2000 (Platyhelminthes, Kalyptorhynchia, Polycystididae). Zootaxa 5659 (3): 357-376, DOI: 10.11646/zootaxa.5659.3.3, URL: https://doi.org/10.11646/zootaxa.5659.3.3
98575F6FFFAAFFA0FF39F9A54902EDB4.taxon	materials_examined	Material examined. Eight whole mounts, one of which designated the holotype (FMNH http: // id. luomus. fi / KV. 547), the rest deposited as reference material in the collections of Hasselt University (HU XXIII. 4.29 – HU XXIII. 4.35). One whole mount (HU XXIII. 4.31) could not be measured. One serially sectioned specimen (HU XXIII. 4.36).	en	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. (2025): On the genus Lagenopolycystis Artois and Schockaert, 2000 (Platyhelminthes, Kalyptorhynchia, Polycystididae). Zootaxa 5659 (3): 357-376, DOI: 10.11646/zootaxa.5659.3.3, URL: https://doi.org/10.11646/zootaxa.5659.3.3
98575F6FFFAAFFA0FF39F9A54902EDB4.taxon	etymology	Etymology. The species name refers to the variable position of the accessory stylet. Mutabilis (Lat.): changeable.	en	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. (2025): On the genus Lagenopolycystis Artois and Schockaert, 2000 (Platyhelminthes, Kalyptorhynchia, Polycystididae). Zootaxa 5659 (3): 357-376, DOI: 10.11646/zootaxa.5659.3.3, URL: https://doi.org/10.11646/zootaxa.5659.3.3
98575F6FFFAAFFA0FF39F9A54902EDB4.taxon	discussion	Additional remarks. The ratio length of accessory stylet / prostate stylet is extremely small in this species, which makes it very easy to distinguish from all other species within the genus. In most specimens, the accessory stylet is somewhat comma-shaped, whereas in one specimen from McKenzie Point (UH XXIII. 4.32; Fig. 7 B, F) it is more straight. Moreover, the position of the accessory stylet seems to vary slightly from specimen to specimen, especially when only looking at the distal part of this stylet. However, it is always attached just distally from the curl, which is apparent when carefully observing the very position of attachment.	en	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. (2025): On the genus Lagenopolycystis Artois and Schockaert, 2000 (Platyhelminthes, Kalyptorhynchia, Polycystididae). Zootaxa 5659 (3): 357-376, DOI: 10.11646/zootaxa.5659.3.3, URL: https://doi.org/10.11646/zootaxa.5659.3.3
98575F6FFFA9FFA2FF39FF6849C9ECE2.taxon	description	urn: lsid: zoobank. org: act: A 288 E 4 FA- 6513 - 49 BA-BE 03 - 6 DE 6 D 9 E 76551 (Fig. 8)	en	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. (2025): On the genus Lagenopolycystis Artois and Schockaert, 2000 (Platyhelminthes, Kalyptorhynchia, Polycystididae). Zootaxa 5659 (3): 357-376, DOI: 10.11646/zootaxa.5659.3.3, URL: https://doi.org/10.11646/zootaxa.5659.3.3
98575F6FFFA9FFA2FF39FF6849C9ECE2.taxon	diagnosis	Diagnosis. Species of Lagenopolycystis with a prostate stylet of 78 – 133 µm (x ̄ = 106 µm, n = 17), strongly curved proximally and slightly curved distally with a (more or less) straight part in between and with a blunt distal end; both ‘ walls’ of the gutter are proximally ear-shaped with a highly thickened rim. The accessory stylet is 37 – 66 µm (x ̄ = 57 µm, n = 16) and has a sharp end. It is attached to the proximal end of the main stylet at about 1 / 4 of its length. The tube of the ‘ seminal receptacle’ is unknown.	en	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. (2025): On the genus Lagenopolycystis Artois and Schockaert, 2000 (Platyhelminthes, Kalyptorhynchia, Polycystididae). Zootaxa 5659 (3): 357-376, DOI: 10.11646/zootaxa.5659.3.3, URL: https://doi.org/10.11646/zootaxa.5659.3.3
98575F6FFFA9FFA2FF39FF6849C9ECE2.taxon	distribution	Distribution. SPAIN • Atlantic coast west of Rota, N 36 ° 3 ’ 0 ” W 6 ° 2 ’ 5 ”, rocky coast, coarse-grained sand on and between rocks (11 April 2008) (TYPE LOCALITY); Mediterranean, Portbou, Punta del Claper, small rock island just south of harbour, N 42 ° 25 ’ 31 ” E 3 ° 10 ’ 15 ”, fine sand, mixed with some shell grit and some silt, 25 m deep (19 July 2021); same locality and habitat, N 42 ° 25 ’ 29 ” E 3 ° 10 ’ 17 ”, 22 m deep (19 July 2021). FRANCE • Cerbère, Peyrefite Bay, in the middle of the bay, N 42 ° 27 ’ 38 ” E 3 ° 09 ’ 36 ”, sand bank between seagrass beds, shell grit mixed with fine gravel, 13 m deep (11 September 2023); Cerbère, ‘ Les Chambres’, sand area between rocks, N 42 ° 26 ’ 30 ” E 3 ° 10 ’ 21 ”, very coarse sand mixed with shell grit, 5 – 6 m deep (31 July 2014); same locality, sand area between seagrass beds, N 42 ° 26 ’ 31 ” E 3 ° 10 ’ 19 ”, coarse sand mixed with some shell grit, 14 m deep (4 August 2014); same locality, past the coastal rock zone, N 42 ° 26 ’ 32 ” E 3 ° 10 ’ 20 ”, clean medium sand mixed with some fine shell grit, 19 m deep (27 May 2023); Cerbère, Terrimbo, Les Aloès, in front of jetty, past the coastal rock zone, N 42 ° 27 ’ 09 ” E 3 ° 09 ’ 46 ”, fine gravel with some silt, 9 m deep (20 July 2010); same locality, N 42 ° 27 ’ 09 ” E 3 ° 09 ’ 48 ”, clean fine sand, 9 m deep (5 August 2014); same locality, habitat, and depth (29 August 2016); same locality, at the foot of a rock forming a little island on the left side of the jetty, N 42 ° 27 ’ 12 ” E 3 ° 09 ’ 42 ”, medium sand mixed with some fine gravel, shell grit, silt, and debris of seagrass leaves, 4 m deep (8 September 2024). FRANCE, CORSICA • Bay of Calvi, in front of the Caldano tip, N 42 ° 3 ’ 0 ” E 8 ° 4 ’ 2 ”, sandy sediment, 32 m deep (11 April 1983). ITALY, SARDINIA • Tonnara, south of Stintino, at the debouchments of a small river, associated with algae (19 August 1994); Punta Negra, sand from gully, 30 cm deep (22 August 1994); same locality; among algae on rocks, submerged next to the small pier at high tide (20 June 2007); same locality; one specimen on very silty algae and the other in coarse-grained sand among rocks, near the pier, salinity 37 ‰ (11 August 2024). PORTUGAL • Carvoeiro, Algarve, beach below Vale de Covo, eastern rocks on main beach, N 37 ° ’ 3 ” W 8 ° 2 ’ 3 ”, algae and sand scraped from rocks, 5 m deep (27 May 2013). SWEDEN • Skagerrak, Bohusten near Bonden, shell gravel, 20 – 30 m deep (Leg. Dr T. Karling, 7 August 1961).	en	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. (2025): On the genus Lagenopolycystis Artois and Schockaert, 2000 (Platyhelminthes, Kalyptorhynchia, Polycystididae). Zootaxa 5659 (3): 357-376, DOI: 10.11646/zootaxa.5659.3.3, URL: https://doi.org/10.11646/zootaxa.5659.3.3
98575F6FFFA9FFA2FF39FF6849C9ECE2.taxon	materials_examined	Material examined. Eighteen whole mounts, one of which designated holotype (FMNH http: // id. luomus. fi / KV. 548), the rest deposited as reference material in the collections of Hasselt University (HU XXIII. 4.37 – XXIV. 1.03). The stylets of one specimen (HU XXIII. 4.37) could not be meaured at all, while in another one (HU XXIV. 1.01) only the prostate stylet could be measured.	en	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. (2025): On the genus Lagenopolycystis Artois and Schockaert, 2000 (Platyhelminthes, Kalyptorhynchia, Polycystididae). Zootaxa 5659 (3): 357-376, DOI: 10.11646/zootaxa.5659.3.3, URL: https://doi.org/10.11646/zootaxa.5659.3.3
98575F6FFFA9FFA2FF39FF6849C9ECE2.taxon	etymology	Etymology. Species name refers to the Phoenicians, the ancient civilization (1550 – 300 BC) that spread across the Mediterranean, founding many colonies, including Olbia (Sardinia) and Cádiz (southern Spain). Poenus (Lat.): Phoenician, Carthaginian.	en	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. (2025): On the genus Lagenopolycystis Artois and Schockaert, 2000 (Platyhelminthes, Kalyptorhynchia, Polycystididae). Zootaxa 5659 (3): 357-376, DOI: 10.11646/zootaxa.5659.3.3, URL: https://doi.org/10.11646/zootaxa.5659.3.3
98575F6FFFA9FFA2FF39FF6849C9ECE2.taxon	discussion	Additional remarks. Due to the ear-shaped proximal parts of the main stylet, the stylet resembles that of L. peresi at first glance. However, the stylet of L. poena sp. nov. is not regularly curved over its whole length, it is slightly larger than that of L. peresi, and the accessory stylet is attached more proximally to the main stylet.	en	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. (2025): On the genus Lagenopolycystis Artois and Schockaert, 2000 (Platyhelminthes, Kalyptorhynchia, Polycystididae). Zootaxa 5659 (3): 357-376, DOI: 10.11646/zootaxa.5659.3.3, URL: https://doi.org/10.11646/zootaxa.5659.3.3
98575F6FFFA9FFBFFF39F91449BAE88A.taxon	description	(Fig. 9)	en	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. (2025): On the genus Lagenopolycystis Artois and Schockaert, 2000 (Platyhelminthes, Kalyptorhynchia, Polycystididae). Zootaxa 5659 (3): 357-376, DOI: 10.11646/zootaxa.5659.3.3, URL: https://doi.org/10.11646/zootaxa.5659.3.3
98575F6FFFA9FFBFFF39F91449BAE88A.taxon	diagnosis	Emended diagnosis after Willems and Artois, 2017. Species of Lagenopolycystis with a robust, approximately boot-shaped prostate stylet measuring 150 µm in length (n = 1). The prostate stylet features a broad, gutter-like structure with a proximal funnel-shaped region adorned with a thick, textured rim. It bends perpendicularly at approximately two-thirds of its length, terminating in a blunt, club-shaped end. The accessory stylet, measuring 66 µm in length, is a simple needle-like structure that attaches to the proximal end of the prostate stylet via a narrow connection. The tube of the ‘ seminal receptacle’ is unknown.	en	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. (2025): On the genus Lagenopolycystis Artois and Schockaert, 2000 (Platyhelminthes, Kalyptorhynchia, Polycystididae). Zootaxa 5659 (3): 357-376, DOI: 10.11646/zootaxa.5659.3.3, URL: https://doi.org/10.11646/zootaxa.5659.3.3
98575F6FFFA9FFBFFF39F91449BAE88A.taxon	distribution	Distribution. SOUTH AFRICA • iSimangaliso-Sodwana Bay, near the lighthouse on a strongly exposed, steep beach, coarse sand with short seaweeds on the upper edge of swirl holes (10 December 2009).	en	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. (2025): On the genus Lagenopolycystis Artois and Schockaert, 2000 (Platyhelminthes, Kalyptorhynchia, Polycystididae). Zootaxa 5659 (3): 357-376, DOI: 10.11646/zootaxa.5659.3.3, URL: https://doi.org/10.11646/zootaxa.5659.3.3
98575F6FFFA9FFBFFF39F91449BAE88A.taxon	materials_examined	Material examined. The holotype (SMNH-Type nr. 8858). Field notes and pictures of a second specimen, which was the specimen used for the molecular analyses by Tessens et al. (2014).	en	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. (2025): On the genus Lagenopolycystis Artois and Schockaert, 2000 (Platyhelminthes, Kalyptorhynchia, Polycystididae). Zootaxa 5659 (3): 357-376, DOI: 10.11646/zootaxa.5659.3.3, URL: https://doi.org/10.11646/zootaxa.5659.3.3
98575F6FFFA9FFBFFF39F91449BAE88A.taxon	discussion	Additional remarks. The hard parts of the male copulatory organ most resemble those of L. poena sp. nov., although those of L. mandelai are much larger. Our measurements revealed that the stylet is actually considerably larger than what is mentioned in the original description by Willems et al. (2017): 150 µm vs 115 µm; the length mentioned in the original description clearly being a lapsus calami. Furthermore, in both the holotype and a second specimen that was only observed alive, the stylet bends perpendicularly at more or less 2 / 3 of its length, i. e. the distal part of the stylet makes a 90 ° turn in the opposite direction as the accessory stylet is pointing. This feature clearly distinguishes L. mandelai from all other species of Lagenopolycystis. Final remarks Lagenopolycystis is a highly homogeneous taxon: all species possess eyes, the proboscis size is approximately 1 / 4 – 1 / 5 of the body length, and the hard parts of the copulatory organ are very similar, differing only in species-specific details. The female atrial organs are also remarkably similar within the genus, and form the main difference with species of Typhlopolycystis, all of which have a well-developed, pear-shaped seminal receptacle. Such homogeneity is also seen in the other genera within the subfamily Typhlopolycystidinae, all of which contain species that can only be distinguished morphologically based on differences in the shape and the dimensions of the stylets (see Artois et al. 2012; Schockaert et al. 2014, 2019). Except for two species from East and South Africa with a very distinctive morphology of the hard parts of the copulatory organ (L. mandelai and L mutabilis sp. nov., respectively), all known species of Lagenopolycystis occur in the Mediterranean and / or in the Macaronesian archipelagos, at least in the Azores and Canary Islands. These species share an overall similar stylet morphology. If our assumption about the erroneous record of L. peresi in Sweden is correct (see Additional information under that species), L. poena sp. nov. is the only species to occur from the Mediterranean to the northern Atlantic. Although highly speculative, the genus may have originated in the Mediterranean and dispersed to other areas, particularly Macaronesia. Lagenopolycystis articulata sp. nov. and L. azorensis sp. nov. occur in both of these areas, while L. peresi and L. conglobata sp. nov. appear to be restricted to the Mediterranean. Lagenopolycystis canariensis sp. nov. has only been found in Macaronesia. On a microscale, several species occur at exact the same locality, and even in exactly the same sample. This is the case for L. peresi and L. poena sp. nov. (in France, Cerbère, Terrimbo, N 42 ° 27 ’ 09 ” E 3 ° 09 ’ 48 ” and Spain, Portbou, N 42 ° 25 ’ 29 ” E 3 ° 10 ’ 17 ”); L. peresi and L. azorensis sp. nov. (in France, Cerbère, Terrimbo, N 42 ° 27 ’ 12 ” E 3 ° 09 ’ 42 ” and “ Les Chambres ” N 42 ° 26 ’ 30 ” E 3 ° 10 ’ 21 ”), L. conglobata sp. nov. and L. poena sp. nov. (in France, Cerbère, “ Les Chambres ”, N 42 ° 26 ’ 31 ” E 3 ° 10 ’ 19 ” and N 42 ° 26 ’ 32 ” E 3 ° 10 ’ 20 ”), L. conglobata sp. nov. and L. azorensis sp. nov. (in France, Banyuls-sur-Mère, N 42 ° 28 ’ 57 ” E 3 ° 08 ’ 16 ” and N 42 ° 28 ’ 56 ” E 3 ° 08 ’ 09. ”) and for L. conglobata sp. nov. and L. peresi sp. nov. (in France, Cerbère, Cap Peyrefite, N 42 ° 27 ’ 24 ” E 3 ° 10 ’ 15 ”). An overview of the occurences of each of the species is provided in Fig. 10. Five of the seven species of Lagenopolycystis have been used in the molecular phylogenetic analysis of Tessens et al. (2014). Lagenopolycystis forms a well-supported clade, demonstrating the monophyly of the genus, within a clade that also includes two species of Brunetorhynchus, one species of Typhlopolycystis, and a species of a Typhlopolycystis - like new genus, marked as Typhlopolycystis sp. in the cladogram (Fig. 11).	en	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. (2025): On the genus Lagenopolycystis Artois and Schockaert, 2000 (Platyhelminthes, Kalyptorhynchia, Polycystididae). Zootaxa 5659 (3): 357-376, DOI: 10.11646/zootaxa.5659.3.3, URL: https://doi.org/10.11646/zootaxa.5659.3.3
