Chorizogynopora italica Kolasa, 1981

Houben, Albrecht M., Monnens, Marlies, Proesmans, Willem & Artois, Tom J., 2022, Limnoterrestrial ‘ Typhloplanidae’ (Rhabdocoela, Platyhelminthes), with the description of four new species and a new genus, European Journal of Taxonomy 798, pp. 70-102 : 84-86

Chorizogynopora italica Kolasa, 1981

Fig. 6

Material examined

GERMANY • 1 spec., studied alive; Schlitz-Breitenbach; 50°39′31″ N, 09°37′46″ E; 9 Aug. 2011; A.M. Houben and W. Proesmans leg.; mossy rocks • 2 specs, studied alive; Wasserküppe; 50°29′27″ N, 09°56′52″ E; 10 Aug. 2011; A.M. Houben and W. Proesmans leg.; moss (Fontinalis sp.) near the source of the river Fulda • 2 specs, studied alive and serially sectioned; same collection data as for preceding; 50°29′21″ N, 09°56′57″ E; XIV.2.39–XIV.2.40; HU • 4 specs, studied alive, one of which serially sectioned; Graswiesenbach, Vogelsberg ; dark moss in fast-flowing water, on rocks in and just above the water; 50°32′08″ N, 09°12′00″ E; 10 Aug. 2011; A.M. Houben and W. Proesmans leg.; XIV.2.41; HU.

Description and discussion

Habitus and internal organisation indicate that these specimens belong to Chorizogynopora italica. Although this species was properly described and illustrated by Kolasa (1981b), there are some small differences between our specimens and the original description. Therefore, we here provide a reconstruction of the genital system of our specimens.

The examined specimens are 0.7–0.8 mm long and very translucent. The body shape is blunt to rounded anteriorly and usually round with sometimes a small tail posteriorly ( Fig. 6A ). Adenal rhabdite glands ( Fig. 6A : ar) are situated at 25% of the body and give rise to two tracts that extend to the anterior body tip, partly anastomosing at their distal end. Dermal rhabdites were not observed. Paired protonephridiopores lie posterior to the rosulate pharynx ( Fig. 6A : ph), which lies just behind the centre of the body.

The gonopore ( Fig. 6A–C : gp) is situated at ±80% of the body and connected to a genital atrium ( Fig. 6A–C : ga). The latter is surrounded by an inner circular and outer longitudinal muscle layer.

The paired, large testes ( Fig. 6A : t) lie just anterior to the pharynx and ventral to the paired vitellaria ( Fig. 6A–B : vi). Both broad vasa deferentia ( Fig. 6B–C : vde) narrow gradually and fuse just before entering the copulatory bulbus. Two layers of spiral muscles surround the 52 µm long, oval-shaped copulatory organ ( Fig. 6A : co), which comprises an intracapsular seminal vesicle ( Fig. 6B–C : vs) and a slightly sclerotised ejaculatory duct ( Fig. 6B–C : de). The duct is surrounded by circular muscles (see Fig. 6B ). Large, coarse-grained, extracapsular eosinophilic glands ( Fig. 6A–C : gg) enter the copulatory organ at the proximal end. A short male duct ( Fig. 6C : md) connects the copulatory organ to the genital atrium. A small muscular bursa ( Fig. 6A–C : bu) containing sperm and prostate secretion is directly connected to the genital atrium. Its shape varies greatly between individuals. In some specimens, it is very narrow and elongate, while in others it is more egg-shaped. In some live specimens, groups of small spines were observed at both the proximal and distal end of the bursa, with the larger ones found at the distal end. Also associated with the bursa are some strong retractor muscles ( Fig. 6C : rm), which are anchored to the dorsal epidermis.

The vitellaria ( Fig. 6A–B : vi) extend at both sides of the body, from just behind the rhabdite glands to the level of the gonopore. The female duct ( Fig. 6C : fd) is relatively broad, surrounded by muscles and lined with a high, nuclear epithelium. It receives the oviduct ( Fig. 6C : od), a long seminal receptacle ( Fig. 6A–C : rs), and the common vitelloduct ( Fig. 6C : vd) proximally. A small muscular evagination of the atrium, which might serve as a uterus ( Fig. 6C : ut), is present.

The testes of our specimens are relatively larger, and the uterus relatively smaller than those described by Kolasa (1981b). Furthermore, Kolasa (1981b) observed tail glands, which we did not observe in our specimens. Despite these small differences the specimens studied are identified as C. italica due to their typical body shape, the presence of an elongated seminal receptacle, and the detailed structure of both the copulatory organ and the bursa.

Kolasa (1981b) described substantial differences between C. italica and C. paradoxa Reisinger, 1924, which is the only other species of Chorizogynopora Reisinger, 1924. Nevertheless, he distinctly mentioned these differences are probably not significant at the genus level. For a detailed discussion, the reader is referred to Kolasa (1981b).

Remarks

Specimens with one egg were observed. It was not possible to ascertain whether it was carried in the atrium or the uterus. Nematodes were observed in the gut of specimens.

Previously known distribution

Tuscany, Italy, in heavily moistened mosses growing in the stream Fosso Contesora ( Kolasa 1981b).

Figures

Fig. 6. Chorizogynopora italica Kolasa, 1981.A. Internal organisation of a live specimen.B. Organisation of the genital system of a live specimen. C. Reconstruction of reproductive organs based on sagittal sections.