Reinhardorhynchus beatrizae 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 : 472-473

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

( Fig. 10 )

urn:lsid:zoobank.org:act:7191A493-CCA1-421D-88D5-99AD3D7E5705

Material and distribution. Observations on live specimens, whole mounted afterwards. Two whole mounts from Las Sardinas (19°56’24”N; 76°46’41”W) (Type Locality), Guamá , Santiago de Cuba, Cuba (June 22, 2016), one of which is designated holotype ( FMNH https://id.luomus.fi/ KV.649), the other one in HU ( XIII.4.03), silty sand in rock pools protected from wave action, 0.3 m deep, salinity 33 ‰. Six whole mounts and three serially-sectioned specimens (in poor conditions) from Siboney (19°57’34”N; 75°42’07”W), Santiago de Cuba, Cuba (September 4, 2016; March 22 & June 5, 2017), intertidal (upper 10 cm of fine-grained sand) up to 0.5 m deep (fine-grained sand rich in organic matter), salinity 33–35 ‰ (HU XIII.4.04– XIII.4.13). Two whole mounts from Bueycabón (19°57’38”N; 76°57’28”W), Santiago de Cuba, Cuba (February 6 & 21, 2018), fine-grained sand rich in organic matter, 0.5 m deep, salinity 33 ‰ (HU XIII.4.14– XIII.4.15) .

Etymology. Species dedicated to Prof. Dr. Beatriz Martínez Daranas, researcher at the Marine Research Centre of Havana University, Cuba), specialist in taxonomy and ecology of seagrass and macroalgae.

Diagnosis. Species of Reinhardorhynchus gen. n. with the copulatory bulb encompassing the prostate vesicle, an armed cirrus and two distal hooks. Cirrus armed with triangular, ±4-μm-long spines. Cirrus also includes a ±347- μm-long spiny belt. Proximally in the belt the spines are scale shaped and ±23 μm long. Proximal spines followed by a section bearing ±6-μm-long spines that runs distally and ends in the distal comb-shaped part, which is armed with ±32-μm-long spines. Larger hook ±101 μm long and ±59 μm wide at its base. Its base bears a ±45-μm-long and funnel-like hook. Smaller hook ±89 μm long and ±47 μm wide at its base.

Description. Live specimens are 1.5–2 mm long, translucent, with two eyes ( Fig. 10A : e). The syncytial and fully-ciliated epidermis is 7–8 μm thick and contains large vacuoles, some of which are filled with a dark granular secretion. Rhabdites occur all over the basal part of the epidermis and measure 2–3 μm.

The proboscis ( Fig. 10A : pr) is of the typical koinocystidid construction (see Brunet 1972; Karling 1980), with a strong juncture sphincter, and does not differ in morphology from that of the other species of Reinhardorhynchus gen n. It is about 15% of the body length in live specimens. Only two pairs of integument retractors were observed: a ventral and a dorsal one. Two pairs of proboscis retractors were observed, but it is not clear whether more are present. The exact number of fixators and dilatators could not be determined. A sphincter around the proboscis pore was not observed.

The pharynx is located at 40–50% ( Fig. 10A : ph) and has a diameter of 15% of the body length in live specimens. Its overall morphology does not differ from that previously described for I. divae (see above). At least two types of glands open in the distal part of the pharynx lumen: one containing a coarse-grained secretion, the other one a fine-grained secretion.

A pair of testes is located rostral to the pharynx. The seminal vesicles fuse with each other just before entering the copulatory bulb. The copulatory bulb is globular and 253–400 μm long (x̄ = 327 μm; n = 7). It is surrounded by an external, longitudinal and a very strong internal, circular muscle layer. The prostate glands open proximally into the copulatory bulb. The copulatory bulb encompasses the prostate vesicle, the cirrus and two distal hooks. The prostate vesicle ( Fig. 10A : pv) opens proximally into the cirrus. The filiform prostate ducts contain a coarse-grained secretion. The cirrus is surrounded by an external longitudinal and a very strong internal circular muscle layer. The cirrus ( Fig. 10A : ci) is armed with 3–5-μm-long triangular spines ( Fig. 10B : cis) (x̄ = 4 μm; n = 20). Additionally, the cirrus also shows a 290–382-μm-long spiny belt (x̄ = 347 μm; n = 6) ( Fig. 10C ). Proximally, these scale-like spines are 9–34 μm long (x̄ = 23 μm; n = 15) ( Fig. 10B–C : cps). This part is followed by a row of triangular and 4–8-μm-long (x̄ = 6 μm; n = 31) spines ( Fig. 10C : cms). In the distal, comb-shaped part of the belt the spines are 23–48 μm long (x̄ = 32 μm; n = 31) ( Fig. 10B–C : cds).

The larger of the two distal hooks ( Fig. 10B : h1, 10D; hooks Fig. 10A : h) is 86–121 μm long (x̄ = 101 μm; n = 7) and 49–72 μm wide at its base (x̄ = 59 μm; n = 8). The base carries a funnel-like structure of 35–53 μm long (x̄ = 45 μm; n = 7) ( Fig. 10B & 10D : fh). The smaller hook ( Fig. 10B : h 2, 10E) is 57–94 μm long (x̄ = 89 μm; n = 6) and 36–55 μm wide at its base (x̄ = 47 μm; n = 6).

The vitellaria run from the posterior end of the pharynx to the caudal body end. The elongated ovaries are located rostral to the copulatory bulb. The oocytes are organised in one row, increasing in diameter from the most proximal to the most distal one. The oviducts open into the proximal end of the female duct. The female duct opens into the receptacle bursa (terminology of Karling 1981; followed by Reygel et al. 2011) through a strong sphincter. The muscular bursal stalk connects the caudally-located bursa with the female atrium. In a live specimen, an egg without shell was observed.

Figures

FIGURE 10. Reinhardorhynchus beatrizae sp. n.. A, general organisation. B, sclerotised structures of the copulatory bulb. C, Cirrus. D, larger hook. E, smaller hook. B–E, from the holotype. C–E with proximal end toward top of figure.