Krumbachia subterranea Reisinger, 1933

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 : 90-92

Krumbachia subterranea Reisinger, 1933

Fig. 8A–C

Material examined

Neotype GERMANY • 1 spec., studied alive and sagittally sectioned; Hessen; 50°46′30″ N, 09°30′18″ E; 9 Aug. 2011; A.M. Houben and W. Proesmans leg.; submersed meadow at the banks of the Breitenbach creek; neotype no. 823 ; HU.

Reference material

GERMANY • 1 spec., live observations; same collection data as for neotype .

Description

The examined specimens are around 2.5 mm long. The body is slender with a somewhat pointy anterior end and rounded posteriorly (see Fig. 8A ). Adenal rhabdite glands occur just behind the brain ( Fig. 8A : ar). Paired protonephridiopores (pp) are positioned ventrally, very near to the mouth ( Fig. 8A : pp). A rosulate pharynx ( Fig. 8A : ph) is situated just behind the centre of the body.

The gonopore ( Fig. 8A–C : gp) is located at ±75% of the body and connected to the gonoduct ( Fig. 8B– C : gd). The gonoduct is surrounded by an inner circular and outer longitudinal muscle layer, and lined with a ciliated, nuclear epithelium resembling the epidermis. The genital atrium ( Fig. 8A–C : ga) is surrounded by a similar musculature and lined with a high, nucleated epithelium. On both lateral sides of the genital atrium, a group of proliferating cells ( Fig. 8C : pc) is found. A large group of eosinophilic glands is situated posterior to the genital atrium and probably enters this atrium anteriorly (not drawn on the reconstruction).

The large, egg-shaped testes ( Fig. 8A : t) lie anterior to the pharynx and ventral to the vitellaria ( Fig. 8A– B : vi). Paired vasa deferentia unite to form a single vas deferens ( Fig. 8A–C : vde) just before entering the copulatory bulbus ( Fig. 8A : co). Two layers of spiral muscles surround the long, curved copulatory organ, which bends up to 80° towards its distal end. The copulatory organ bears an intracapsular seminal vesicle ( Fig. 8B–C : vs) and a strongly sclerotised ejaculatory duct ( Fig. 8B–C : de). Several coarsegrained, extracapsular eosinophilic glands ( Fig. 8A–C : gg) enter the copulatory organ at the proximal end. Their secretion is lightly basophilic when entering the copulatory organ, however, it becomes strongly eosinophilic in the ejaculatory duct. A cone-shaped bursa ( Fig. 8A–C : bu), surrounded by strong inner circular and outer longitudinal muscles, lies next to the copulatory organ and opens into the genital atrium.

The vitellaria extend from the region of the rhabdite glands to the posterior end ( Fig. 8A : vi). The vitelloducts ( Fig. 8C : vd) fuse just before opening into the female duct ( Fig. 8C : fd). Furthermore, this duct is surrounded by a layer of circular muscles and receives the oviduct, a seminal receptacle ( Fig. 8A–C : rs), and the female glands ( Fig. 8C : fg). The seminal receptacle is provided with a short stalk, which also is surrounded by circular muscles.

Discussion

See the general discussion on the genus Krumbachia Reisinger, 1924 .

Previously known distribution

Ruhr, Germany ( Reisinger 1933), riparian forest near Schlitz, Germany ( Schwank 1981). Common species in Europe ( Lanfranchi & Papi 1978).

Figures

Fig. 8. Two species of Krumbachia Reisinger, 1924. A–C. Krumbachia subterranea Reisinger, 1933. 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 of the neotype (neotype no. 823). D–E. Krumbachia virginiana (Kepner & Carter, 1931) Ruebush, 1938. D. Internal organisation of a live specimen. E. Reconstruction of reproductive organs based on sagittal sections.