Reinhardorhynchus pacificus Diez, 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 : 476-478

Reinhardorhynchus pacificus Diez, Reygel & Artois sp. n.

( Fig. 12D–F , 13 )

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Material and distribution. Observations on live specimens, whole mounted afterwards. Two whole mounts collected in Playa Venao ( 08°53’06”N; 79°36’07”W) (Type Locality), Vera Cruz, Panama ( December 2, 2011), one of which is designated holotype ( USNM 1642506 ), the other one in the USNM (1642507), coarse-grained sand with fine silt, salinity 30 ‰.

Etymology. The two specimens were found at the Pacific coast of Panama.

Diagnosis. Species of Reinhardorhynchus gen. n. with a copulatory bulb encompassing a papillary cirrus, an ejaculatory cirrus, an accessory cirrus, and two hooks. Ejaculatory cirrus ±171 μm long, armed with scale-like spines along its entire length that are ±5 μm wide proximally and ±2 μm wide distally. Few larger triangular spines occur proximally (±10 μm long) and distally (±4 μm long). Accessory cirrus ±92 μm long, proximally armed with ±6-μm-long triangular spines and distally with 3-μm-long triangular spines and ±3-μm-wide and scale-like spines. Distal rims of these spines serrated, bearing ±1-μm-long spinules. Papillary cirrus ±62 μm long, proximally cov- ered by fine spines of ±2 μm long and distally with ±6-μm-long triangular spines. The hooks are ±83 μm long and ±81 μm long, respectively.

Description. The specimens are 1.7 mm long, colourless, with two eyes ( Fig. 13A : e). The brain ( Fig. 13A : br) is located caudally from the proboscis. The proboscis ( Fig. 13A : pr) has the typical koinocystidid morphology (see Brunet 1972; Karling 1980) and shows a strong junction sphincter; it represents 10% of the body length in live specimens. The pharynx ( Fig. 13A : ph) has a diameter of ±15% of the body length in live specimens, and is located at 30–40%. Caudally in the body some eosinophilic glands occur ( Fig. 13A : cgl).

The two testes ( Fig. 13A : t) are located rostrally from the pharynx. The seminal vesicles ( Fig. 12D & 13A : sv) fuse proximally from the copulatory bulb, forming a short seminal duct. The copulatory bulb is 363–403 μm long ( x̄ = 383 μm; n = 2). It encompasses the prostate vesicle ( Fig. 13A : pv), the ejaculatory cirrus (terminology of Karling 1978), an accessory cirrus, a papillary cirrus (terminology of Karling 1978), and two distal hooks. The ejaculatory cirrus ( Fig. 12D–E & 13A : ci, 13B) is 162–180 μm long ( x̄ = 171 μm; n = 2) and armed with scalelike spines over its entire length. These spines are 5–6 μm wide ( x̄ = 5 μm; n = 20) proximally and 2–3 μm wide ( x̄ = 2 μm; n = 20) distally. Additionally, a number of larger triangular spines occur proximally, measuring 6–13 μm ( x̄ = 10 μm; n = 10), and a group of small triangular spines is present distally, measuring 3–4 μm ( x̄ = 4 μm; n = 13). The accessory cirrus ( Fig. 12D–E & 13A : ac, 13C) is 89–95 μm long ( x̄ = 92 μm; n = 2), proximally armed with triangular spines 4–10 μm long ( x̄ = 6 μm; n = 24) and distally with triangular spines 2–4 μm long ( x̄ = 3 μm; n = 9) and scale-like spines 2–5 μm wide ( x̄ = 3 μm; n = 15). The distal rim of the scale-like spines of the accessory cirrus is serrated, with 1-μm-long spinules. The spiny part of the papillary cirrus ( Fig. 12D–E , 13A & 13D : pc) is 55–69 μm long ( x̄ = 62 μm; n = 2) and proximally enclosed in a papilla ( Fig. 13D : pa). Papilla and cirrus are separated from each other by a sphincter ( Fig. 13D : sph). The papillary cirrus is proximally armed with fine spines, ±2 μm long, and distally with triangular spines, 4–8 μm long ( x̄ = 6 μm; n = 6). The two funnel-shaped distal hooks are nearly equal in size. One hook ( Fig. 12D–E & 13A : h 1, 13E) is 79–86 μm long ( x̄ = 83 μm; n = 2) and 40–43 μm wide at its base ( x̄ = 42 μm; n = 2). The other hook ( Fig. 12D–E & 13A : h2, 13F) is 79–83 μm long ( x̄ = 81 μm; n = 2) and 59–65 μm wide at its base ( x̄ = 62 μm; n = 2).

Vitellaria were not observed. The oval-shaped ovaries ( Fig. 13A : ov) are located rostrally from the copulatory bulb. The oocytes are organised in a row. The oviducts ( Fig. 13A : od) open into the proximal end of the female duct. The female duct ( Fig. 12D, 12F & 13A : fd) opens into the receptacle bursa (terminology of Karling 1981; followed by Reygel et al. 2011) ( Fig. 13A : rb) through a sphincter ( Fig. 13A : sph). The caudally-located bursa ( Fig. 12D, 12F & 13A : b) opens into the female genital atrium via the bursal stalk. The uterus ( Fig. 13A : ut) has a sphincter more or less at its midpoint. The common gonopore ( Fig. 13A : cg) opens at 90%.

Figures

FIGURE 12. A–C, Reinhardorhynchus anamariae sp. n.. A, sclerotised structures of the cirrus. B, cirrus. C, hooks. D–F, Reinhardorhynchus pacificus sp. n.. D–E, sclerotised structures of the cirrus. F, female system. All from the holotype. All with proximal end toward left of figure.

FIGURE 13. Reinhardorhynchus pacificus sp. n.. A, general organisation (from a live animal). B, ejaculatory cirrus. C, accessory cirrus. D, papillary cirrus. E, larger hook. F, smaller hook. B–F, from the holotype. All with proximal end toward top of figure.