Lagenopolycystis articulata Artois and Schockaert, 2025

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), pp. 357-376 : 363-364

Lagenopolycystis articulata Artois and Schockaert sp. nov.

urn:lsid:zoobank.org:act:310DD83C-436F-4DCC-8829-A828BB1C448B

( Fig. 3 )

Lagenopolycystis sp. nov. 3 in Tessens et al. (2014)

Diagnosis. Species of Lagenopolycystis with a proboscis up to 1/4 of the body length. Prostate stylet of 68–88 µm (x̄ = 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 (x̄ = 59 µm, n = 6), sharp ending, slightly curved at its end. The tube of the ‘seminal receptacle’ is about 15 µm, straight and robust.

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, N42°26’29” E3°10’22”, clean, coarse-grained sand and fine gravel, 2–3 m deep (1 August 2008); same locality, N42°26’29” E3°10’21”, sand area between rocks, coarse sand mixed with shell grit, 5–6 m deep (4 August 2014).

ITALY, SARDINIA • Cavaliere, Budelli , N41°17’30” E9°20’52”, medium to fin-grained, rather clean sand, 35 m deep (7 September 2010) .

SPAIN • Portbou , l’Ocell, N42°25’59” E3°10’27”, clean medium sand mixed with shell grit, 18 m deep (20 July 2023) .

SPAIN, LANZAROTE • Punta Jameos del Agua , N29°9’25” W13°25’38”, coarse sand, 12 m deep, salinity 35‰ (15 October 2011) .

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) .

Etymology. According to the notes of Dr M. Brunet, the accessory stylet articulates with the main stylet in the living animal. Articulatus (Lat.) : articulated.

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.

Figures

FIGURE 3. Lagenopolycystis articulata sp. nov. A. Micrograph of a live specimen from Sardinia. B–F. Micrograph and camera lucida drawings of the stylets, including B–C. the holotype (FMNH http://id.luomus.fi/KV.543), and D–F. reference specimens (D: HU XXIII.2.50; E: XXIII.2.48, XXIII.2.49). All drawings same scale. B–D. also include a drawing of the sclerotised duct adjacent to the seminal receptacle.