Lagenopolycystis mandelai Willems and Artois, 2017

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 : 372-375

Lagenopolycystis mandelai Willems and Artois, 2017

( Fig. 9 )

Lagenopolycystis sp. nov. 2 in Tessens et al. (2014)

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.

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).

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).

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, N42°27’09” E3°09’48” and Spain, Portbou, N42°25’29” E3°10’17”); L. peresi and L. azorensis sp. nov. (in France, Cerbère, Terrimbo, N42°27’12” E3°09’42” and “Les Chambres” N42°26’30” E3°10’21”), L. conglobata sp. nov. and L. poena sp. nov. (in France, Cerbère, “Les Chambres”, N42°26’31” E3°10’19” and N42°26’32” E3°10’20”), L. conglobata sp. nov. and L. azorensis sp. nov. (in France, Banyuls-sur-Mère, N42°28’57” E3°08’16” and N42°28’56” E3°08’09.”) and for L. conglobata sp. nov. and L. peresi sp. nov. (in France, Cerbère, Cap Peyrefite, N42°27’24” E3°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 ).

Figures

FIGURE 9. Lagenopolycystis mandelai A. Micrograph and B. camera lucida drawing of the stylet of the holotype (schematized after Willems et al., 2017). C–F. Micrographs of a live specimen, including C., an overview of the entire specimen, D. the proboscis, E. the pharynx, and F. the male copulatory system.

FIGURE 10. Maps indicating the geographical distribution of the species of Lagenopolycystis: A. Worldwide, B. Localities in the Mediterranean and along the Iberian Atlantic coast.

FIGURE 11. Part of the topology of Tessens et al. (2014), with taxon names updated based on recent literature (Schockaert et al., 2014, 2019) and newly established species from this study. Branches without symbols indicate maximum support. Symbols above branches represent posterior probabilities (pp), where ** denotes 0.98 <pp <1. Symbols below branches indicate bootstrap values (bp): ●● denotes 85 <bp <100, and ● denotes 70 <bp <85.