Reinhardorhynchus unicornis Diez, Aguirre, Reygel & Artois, 2021

Diez, Yander L., Monnens, Marlies, Aguirre, Rosa Isabel, Yurduseven, Rana, Jouk, Philippe, Van Steenkiste, Niels W. L., Leander, Brian S., Schockaert, Ernest, Reygel, Patrick, Smeets, Karen & Artois, Tom, 2021, Taxonomy and phylogeny of Koinocystididae (Platyhelminthes, Kalyptorhynchia) with the description of three new genera and twelve new species, Zootaxa 4948 (4), pp. 451-500 : 482

Reinhardorhynchus unicornis Diez, Aguirre, Reygel & Artois sp. n.

( Fig. 16 )

urn:lsid:zoobank.org:act:B5662028-C218-43A0-9A93-7B2557629C76

Material and distribution. One specimen studied alive, whole mounted afterwards, designated holotype ( FMNH https://id.luomus.fi/ KV.653), collected in Guardalavaca (21°07’32”N; 75°49’39”W) (Type Locality), Banes, Holguín, Cuba (February 28, 2017), fine-grained sand in a bed of Syringodium filiforme , 0.2 m deep, salinity 35 ‰.

Etymology. The epithet refers to the copulatory organ, which is armed with a single accessory hook only.

Diagnosis. Species of Reinhardorhynchus gen. n. with a copulatory bulb encompassing an ejaculatory cirrus, a papillary cirrus, and an accessory hook. Ejaculatory cirrus 73 μm long, armed with 5-μm-long, triangular spines. Papillary cirrus 119 μm long, armed with triangular, ±1-μm-long spines which become longer distally, up to ±11 μm. Curved hook 100 μm long and 40 μm wide at its asymmetrical base.

Description. The specimen is 1.6 mm long, unpigmented, with a pair of eyes. The proboscis is about 20% of the body length in the live specimen. As far as could be seen on the live specimen, it shows the distinctive features of the typical koinocystidid proboscis (see Brunet 1972; Karling 1980), with a strong juncture sphincter. The pharynx ( Fig. 16B : ph) has a diameter of 15% of the body length in live specimens, and is located at 40%.

A pair of testes is located rostrally from the pharynx. The seminal vesicles ( Fig. 16A–B & 16E : sv) fuse just before entering the copulatory bulb and form a short ejaculatory duct ( Fig. 16A : ed). The extracapsular prostate glands ( Fig. 16A : pg) open proximally into the copulatory bulb. The copulatory bulb ( Fig. 16A ) encompasses the prostate vesicle ( Fig. 16A–B : pv), an ejaculatory cirrus, a papillary cirrus, and one distal hook. Proximally, a bundle of prostate glands opens into the copulatory bulb. The ejaculatory cirrus ( Fig. 16A–B & 16E–F : ci) is 73 μm long and armed with 4–7-μm-long triangular spines (x̄ = 5 μm; n = 12). The papillary cirrus ( Fig. 16A–B & 16E–F : pc, 16D) is proximally enclosed in a globular papilla ( Fig. 16A : pa). It is 119 μm long and 24 μm wide, and armed with triangular and ±1-μm-long spines; some spines are larger distally (±11 μm long). The caudally-located hook ( Fig. 16A–B & 16E : h, 16C) is 100 μm long and 40 μm wide at its asymmetrical base.

The pair of ovoid ovaries is situated rostrally from the copulatory bulb, with the oocytes organised in a row. The vitellaria ( Fig. 16B : vi) extend from beside the pharynx to the body end.

Figures

FIGURE 16. Reinhardorhynchus unicornis sp. n.. A, copulatory bulb. B, caudal body end. C, hook. D, papillary cirrus. E–F, sclerotised structures of the copulatory bulb. A–B, from the live animal. C–F, from the holotype.A–D & E–F with proximal end toward top of figure, B with proximal end toward left of figure.