Reinhardorhynchus hexacornutus Jouk, Diez, Reygel & Artois 2021, sp. n.
Creators: name: Diez, Yander L.
name: Monnens, Marlies
name: Aguirre, Rosa Isabel
name: Yurduseven, Rana
name: Jouk, Philippe
name: Van Steenkiste, Niels W. L.
name: Leander, Brian S.
name: Schockaert, Ernest
name: Reygel, Patrick
name: Smeets, Karen
name: Artois, Tom
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Animalia
Platyhelminthes
Rhabditophora
Rhabdocoela
Koinocystididae
Reinhardorhynchus
Reinhardorhynchus hexacornutus

description: Reinhardorhynchus hexacornutus Jouk, Diez, Reygel & Artois sp. n.
(Fig. 11)
urn:lsid:zoobank.org:act: 45A01032-0A38-4976-9AF0-B2C6F277FC55
Material and distribution. Observations on live specimens, whole mounted afterwards. Five whole mounts, one
of which is designated holotype (FMNH https://id.luomus.fi/ KV.650), the others in HU (XIII.4.16– XIII.4.19), collected in Puna’auia (17°36’42”S; 149°36’51”W) (Type Locality), Pape’ete, Tahiti, Society Islands, French Polynesia (March 18, 2016), sediment with ripple marks, 50 cm deep, fine black sand.
Etymology. Species named after the presence of six hooks within the copulatory bulb.
Diagnosis. Species of Reinhardorhynchus gen. n. with the copulatory bulb encompassing the ejaculatory duct, a papillary cirrus, and six hooks. Ejaculatory duct runs through the copulatory bulb and opens distally into the male atrium. Papillary cirrus ±84 μm long, armed with nail-shaped spines, ±2 μm long proximally and ±1.2 μm distally. Hooks funnel-shaped, curved, and ending in a sharp tip, each of different size, ranging from 11μm long and 5 μm wide to 54 µm long and 23 µm wide.
Description. The specimens are 0.9–1.3 mm long (x̄ = 1.1 mm; n = 3), translucent, with a pair of eyes (Fig. 11A: e). The proboscis (Fig. 11A: pr) is of the typical koinocystidid construction (see Brunet 1972; Karling 1980), with a strong juncture sphincter. The pharynx (Fig. 11A: ph) has a diameter of 10% of the body length in live specimens, and is located at 30%.
Two testes (Fig. 11A: t) are positioned behind the pharynx. The vasa deferentia form the seminal vesicles (Fig. 11A–B: sv), which fuse to form a short seminal duct just before entering the copulatory bulb. The oval copulatory bulb is 125 μm long (n = 1) and encompasses the ejaculatory duct, a papillary cirrus, and six accessory hooks. The ejaculatory duct (Fig. 11B & 11J: ed) runs through the proximal part of the copulatory bulb and opens distally into the male atrium. The spiny part of the papillary cirrus (Fig. 11A–C & 11J–H: pc) is 73–91 μm long (x̄ = 84 μm; n = 4) and armed with nail-shaped spines. Proximally, these spines are 1.2–2.4 μm long (x̄ = 2 μm; n = 20) and dis- tally they decrease in size to ±1.2 μm (n = 15). Proximally, the papillary cirrus is enclosed in a papilla (Fig. 11A–C & 11J–K: pa), with a glandular organ opening into the cirrus. The accessory hooks (Fig. 11A: h, 11B & 11J–K: h1–h6, 11D–I) are funnel-shaped, curved, and ending in a sharp tip. They differ in size, ranging from 11 µm long and 5 µm wide at the base for the smallest one to 54 μm long and 23 µm wide for the largest one. The hooks are organised in two groups; one group is formed by hooks 1–4 (Fig. 11I, 11G, 11D & 11H, respectively) and the other group includes hooks 5–6 (Fig. 11F & 11E, respectively). The hooks 1–4 are located in a well-developed muscular sac.
The vitellaria (Fig. 11A: vi) extend along both sides of the body from the level of the pharynx to the copulatory organs. A pair of ovaries (Fig. 11A: ov) is located at the midbody, rostral to the copulatory bulb. The oocytes are organised in a row. The oviducts open into the proximal end of the female duct. The female duct (Fig. 11A: fd) opens into the female atrium through a strong sphincter. The muscular bursal stalk (Fig. 11A: bs) connects the caudallylocated bursa (Fig. 11A: b) to the female atrium. The common gonopore (Fig. 11A: cg) opens at 80%.
description: Published as part of 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, pp. 451-500 in Zootaxa 4948 (4) on pages 473-476, DOI: 10.11646/zootaxa.4948.4.1, http://zenodo.org/record/4629235