Duplominona hystricina Curini-Galletti, 2020

Curini-Galletti, Marco, Carcupino, Marcella, Stocchino, Giacinta A., Leasi, Francesca & Norenburg, Jon L., 2020, New species of Duplominona Karling, 1966 (Platyhelminthes, Proseriata) from the Pacific coast of Panama, Zootaxa 4881 (3), pp. 482-498 : 486-487

Duplominona hystricina Curini-Galletti n. sp.

( Fig. 3 )

Holotype. Pacific Ocean: Gulf of Panama, off Isla Pacheca (Las Perlas Is., Panama)(Lat. 8°40’22.87”N; Lon. 79° 3’12.58”W), about 20 m deep, coarse sand with shell fragments, December 2011: one whole mount ( USNM 1622573 ).

Paratypes. Same data as holotype, two specimens sagittally sectioned ( USNM 1622574 ; USNM 1622575 ) .

Other material. Same data as holotype, two specimens observed alive, and prepared as semi-permanent mounts.

Etymology. The name refers to the spiky, Hystrix -like cirrus of the new species.

Description. A minute species, less than 1.5 mm in length, very similar in habitus to the previous species. Anterior tip with oily dots and tiny rod-shaped rhabdoids, about ¼ the diameter of the statocyst. With a short pharynx at about mid-body.

Male genital system. With few (3–5) testes in one medio-ventral row ( Fig. 3A ). With an ovoid copulatory organ, about 35 μm long. Small, spiny cirrus about 15 μm long, provided with 10–12 rows of spines ( Fig. 3 B–E). Spines are 3–5 μm long, slender, slightly recurved, and acutely pointed, with a small, swollen basis, 1–1.5 μm across ( Fig 3 C ). The minute spines of the species are poorly sclerified, and quickly deteriorated in the whole mounts.

Accessory organ about 20 μm across, provided with a pen-nib shaped stylet 12–13 μm long ( Fig 3 G ). It opens to the outside with its own pore.

Female genital system. Ovaries just in front of the pharynx. Vitellaria extending from of anterior testes to bursa. With a small, spherical pre-penial bursa, provided dorsally with a few large resorbiens vacuoles ( Fig. 3 F : rv), abutting the gut lining. With a short and wide vaginal duct. The female duct continues posteriorly to the bursa and opens behind the prostatoid organ pore through the female pore.

Diagnosis. Species of Duplominona with few (3–5) testes. Small cirrus provided with 10–12 rows of acute spines, 3–5 μm high, with swollen bases. With a spherical bursa in front of the copulatory organ, and external va-gina. Accessory organ stylet 12–13 μm long.

Pore index: a: b: c: d = =5: 1.5: 2: 1.

Figures

FIGURE 3. Duplominona hystricina n. sp. (A) Habitus of a living animal; see Fig. 2A for interpretation of anatomical features. (B) Reconstruction of the cirrus. (C) Spine morphology. (D, E) Micrographs of cirri. (F) Reconstruction of the genital areas from sagittal sections. (G) Stylet of the accessory organ. (Scale bars: B, C = 5 μm; D, E, G = 10 μm).