Adenoplea reisingeri Houben, Proesmans and Artois

Houben, Albrecht M., Schwank, Peter, Proesmans, Willem, Bert, Wim & Artois, Tom J., 2015, Notes on some enigmatic taxa of limnoterrestrial rhabdocoels, with the description of two new species, Zootaxa 4040 (1), pp. 83-92 : 84-85

Adenoplea reisingeri Houben, Proesmans and Artois n. sp.

( Fig. 1 A)

Locality. Vyle-et-Tharoul, Liège, Belgium, moss collected along the Rue Pont de Vyle (50°27’06”N; 5°16’46”E), (18 August 2008)

Material. Three serially-sectioned specimens: a sagitally-sectioned one designated holotype ( SMNH, no. 8758), a sagitally-sectioned (HU, no. 573) and a transverse-sectioned one (HU, no. 574), both paratypes.

Etymology. Dedicated to Dr. Erich Reisinger, honouring his contribution to the knowledge of limnoterrestrial rhabdocoels.

Description. Animals about 1 mm long with a white-yellowish colour. Rostrally two groups of adenal rhabdite glands are present. Protonephridiopores were not observed with certainty. The rosulate pharynx is positioned at ±65 % of the body.

The gonopore ( Fig. 1 A: gp) is situated at ±90 % of the body and opens into a genital atrium, which is lined with a high, nucleated epithelium and is surrounded by muscles.

The paired, large testes ( Fig. 1 A: t) lie ventrally to the vitellaria. The paired vasa deferentia ( Fig. 1 A: vde) become somewhat wider before entering the copulatory organ separately through its proximal end. The copulatory organ is 60–65 µm long. It contains an intracapsular spindle-shaped seminal vesicle ( Fig. 1 A: vs), the ejaculatory duct ( Fig. 1 A: de) and coarse-grained eosinophilic ( Fig. 1 A: gg1) and basophilic ( Fig. 1 A: gg2) prostate glands with extracapsular nucleated parts. The copulatory organ is of the inermis-type, i.e. the ejaculatory duct is not provided with sclerotized spines (see Reisinger 1924). Circular muscles surround the ejaculatory duct, and two spirallyrunning muscle layers surround the entire copulatory organ. The male duct ( Fig. 1 A: md) is surrounded by a layer of circular muscles and is lined with a high epithelium. The oval bursa ( Fig. 1 A: bu) is slightly smaller than the copulatory organ, completely surrounded by circular muscles and opens in the distal part of the male duct. The vitellaria extend from the posterior end up to the rhabdite glands. The female duct ( Fig. 1 A: fd) is surrounded with muscles and lined with a high, nucleated epithelium. It receives the oviduct ( Fig. 1 A: od) and the common vitelloduct ( Fig. 1 A: vd) proximally, and the female glands ( Fig. 1 A: fg) somewhat distally from these ducts.

Diagnosis. Species of Adenoplea Reisinger, 1924 , about 1 mm long. Copulatory organ of the inermis-type, containing at least two types of prostate glands, a spindle-shaped seminal vesicle and a muscular ejaculatory duct in its distal third. An elongate, oval-shaped copulatory bursa, which is completely surrounded by circular muscles, is present.

Discussion. See the discussion following the descriptive notes and remarks on Adenoplea perigraptopera Reisinger, 1924 .