Pseudominona cancan Curini-Galletti, 2019

Curini-Galletti, Marco, Stocchino, Giacinta A. & Norenburg, Jon L., 2019, New species of Duplominona Karling, 1966 and Pseudominona Karling, 1978 (Platyhelminthes: Proseriata) from the Caribbean, Zootaxa 4657 (1), pp. 127-147 : 141-142

Pseudominona cancan Curini-Galletti n. sp.

( Fig. 8 )

Holotype. Panama: Portobelo , Bahia Can Can (Lat. 9.517535, Lon. -79.687392), about 50 cm deep among seagrass, in mixed sediment, March 2016; one specimen sagittally sectioned ( USNM 1569257 ).

Paratype. Same data as holotype, two specimens sagittally sectioned ( USNM 1569258–1569259 ) .

Other material. Same data as holotype, three specimens studied karyologically.

Panama: Bocas del Toro (Lat. 9.352219, Lon. -82.255574). Sheltered beach in front of the Smithsonian Tropical Research Institute , intertidal in medium sand. June 2010; one specimen studied alive .

Etymology. The species is named after the type locality— cancan is a noun used in apposition.

Description. Animals small, about 1.5 mm long, unpigmented, with the caudal region tripartite, provide with numerous adhesive glands ( Fig. 8 A–C). Rhabdoids rod-shaped, about 5–7 μm long. Statocyst surrounded by nuclei of the brain cells, and abutting the neuropil. With a short pharynx at about mid-body. Oesophagus less than 1/5 the total length of pharynx.

Male genital system. With about 20 testes in two more or less regular rows in front of pharynx ( Fig. 8 A, B ). With a copulatory organ about 50 μm long and 40 μm high in sections, provided with a thin outer muscular layer, about 1 μm thick. With a nearly spherical seminal vesicle, separated by a muscular septum from a well-developed prostatic vesicle ( Fig. 8 E, G ). Cirrus short, 25–30 μm long, provided with 10–15 rows of acutely triangular spines, 3–5 μm long, progressively increasing in size distally ( Fig. 8 D ).

With an ovoid accessory organ, 20–25 μm across, lined by a muscular coating 2.5 μm thick, and provided with a slender stylet about 22 μm long. The accessory organ opens to the outside through an own pore, just posterior to the male pore ( Fig. 8 E, G ).

Female genital system. Ovaria immediately postpharyngeal. The short oviducts enter a small roundish copulatory bursa ( Fig. 8 F ), connected to a vaginal duct that runs ventrally and opens close to mouth through the vagina. The female duct widens in front of the copulatory organ, and is surrounded by vacuoles containing sperm in various stages of degradation. The female duct opens to the outside posterior to the accessory organ pore ( Fig. 8 G ).

Diagnosis. Species of Pseudominona with tripartite tail. With a short cirrus, with 10–15 rows of acutely triangular spines, 3–5 μm long. With a small bursa in front of the copulatory organ, and an external vagina close to mouth. With a prostatoid organ provided with a slender stylet 22 μm long. Pore indices: a:b:c:d = 1: 14: 2: 4.

Figures

FIGURE 8. Pseudominona cancan n. sp. (A) Habitus of a living animal; see Fig. 1 for interpretation of anatomical features. (B, C) Micrographs of living animals. (D) Micrograph of a frontal section of the post-pharyngeal area. (E) Reconstruction of the inverted cirrus. (F) Micrograph of a sagittal section of the genital organs. (G) Reconstruction of the genital organs from sagittal sections. (Scale bars =10 m).