Proschizorhynchus arnautsae, Gobert & Monnens & Eerdekens & Schockaert & Reygel & Artois, 2020

Gobert, Stefan, Monnens, Marlies, Eerdekens, Lise, Schockaert, Ernest, Reygel, Patrick & Artois, Tom, 2020, Schizorhynchia Meixner, 1928 (Platyhelminthes, Rhabdocoela) of the Iberian Peninsula, with a description of four new species from Portugal, European Journal of Taxonomy 595, pp. 1-17 : 6-8

Proschizorhynchus arnautsae sp. nov.

urn:lsid:zoobank.org:act:E581DF16-97C5-4F81-9702-BB79821AB620

Fig. 2 B–C

Etymology

This species is named in honour of fellow Hasselt University researcher and dear friend to the first author, Natascha Arnauts.

Material examined

Holotype PORTUGAL • 1 whole-mount (photographs of live specimen available); Olhão , Garganta Canal; 37°01′34″ N, 07°50′56″ W; 13 Sep. 2011; E. Schockaert leg.; mid-eulittoral zone, fine, muddy sand; HU 616.

Other material

PORTUGAL • 1 whole-mount (photographs of live specimen available); Algarve region, Faro, Parque Natural da Rio Formosa, Culatra Island ; 37°00′00″ N, 07°49′16″ W; 17 May 2013; B. Tessens leg.; fine, silty sand, with many bivalve shells and seagrass, from creek in a bay on the eastern shore of the island; HU X.1.35 . • 1 whole-mount (photographs of live specimen available); Algarve region, Olhos de Água ; 37°05′20″ N, 08°11′16″ W; 15 May 2013; B. Tessens leg.; coarse sand between rocks on the eastern side of a rocky outcrop; HU X.1.36 • 1 whole-mount (photographs of live specimen available); Algarve region, Olhos de Água ; 37°05′20″ N, 08°11′16″ W; 15 May 2013; B. Tessens leg.; fine clean sand from intertidal at open beach, about 0.5 m deep, west of rocky outcrop; HU X.1.37 .

Description

Live specimens measure approximately 1.6 mm in length and are colourless. Eyes are absent.An elongate split proboscis, approximately 1⁄10 of the total body length (when relaxed), is situated at the anterior end of the body. Connecting proximally to the muscular proboscis is a pair of small gland sacs. A rosulate pharynx is present in the anterior half of the body.

Two small, globular testes are positioned anterior to the pharynx. A pair of seminal vesicles enters an ovoid copulatory bulb, the proximal part of which is occupied by a prostatic bulb. Distally, the copulatory bulb contains the sclerotised copulatory parts ( Fig. 2 B–C), which consist of a very short, slender stylet, set in a cirrus sheath ornamented with parallel longitudinal grooves. The stylet is between 26 and 36 μm long (x = 31 μm, n = 4). In most specimens, the stylet is completely enveloped by the cirrus sheath, meaning the tip does not protrude beyond the distal rim of the copulatory organ. However, in some instances it can protrude a little (as in Fig. 2C ), probably depending on the organ’s contraction or flattening of the specimen. The distal rim of the cirrus sheath does not bear spines.

The female genital system could not be studied in detail.A uterus and bursa were observed to lie caudally with respect to the male copulatory apparatus. A single ovary was observed even more caudally. Paired vitellaria run laterally along either side of the body.

Remarks

See taxonomic discussion following P. reniformis .

Figures

Fig. 2. Copulatory organ of species of Proschizorhynchus Meixner, 1928. A. Proschizorhynchus algarvensis sp. nov., holotype (HU 615). B–C. P. arnautsae sp. nov. B. Holotype (HU 616). C. Aspecimen from the reference collection of Hasselt University (HU X.1.35). D–E. P. troglodytus sp. nov. D. Holotype (HU 617). E. A specimen from the reference collection of Hasselt University (HU X.1.40). F–G. P. pectinatus l’Hardy, 1965 (HU X.1.43). F. Copulatory organ. G. Sclerotised spermatic duct. H. P. reniformis Brunet, 1970 (HU X.1.45). Scale bars: A, F = 50 µm; B–E, G–H = 20 µm.