Duplominona dissimilispina 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 : 134-135

Duplominona dissimilispina Curini-Galletti n. sp.

( Fig. 4 )

Holotype. Puerto Rico: Isla Magueyes. (Lat. 17.969200, Lon. -67.045867), sheltered beach among mangroves, lower intertidal in very silty medium sand, December 1988: original film and printed pictures of the copulatory structures (SMNH-Type 9178).

Paratypes. Same data as holotype, two mature specimens (original film and printed pictures of the copulatory structures) ( CZM 806-807 ) .

Other material. Several specimens observed alive from the type-locality, two used for karyology. Puerto Rico: Harbour of La Parguera (Lat. 17.973256, Lon. -67.046770), lower intertidal in very silty coarse sand, December 1988, several specimens observed alive, one used for karyology.

Etymology. The species’ name reflects the morphological diversity of the spines of its cirrus.

Description. A large and robust Duplominona : living specimens about 2.5 mm long ( Fig. 4 A ). With clusters of long rhabdoids, particularly visible in the tail. Pharynx comparatively small, about midbody.

Male genital system. With 20–30 testes, arranged into two rows. The ovoid copulatory organ has a distinct prostatic vesicle. Cirrus 120–140 μm long, provided with 25–30 rows of spines, tightly packed distally ( Fig. 4 B–D, F). Morphology and size of spines change significantly along the length of cirrus. Proximally, spines are needleshaped, 5–6 μm long; they become progressively longer distally, to 15 μm in length. In the distalmost portion of the cirrus, spines become abruptly shorter, to 5–6 μm in length, with a basis 3–3.5 μm across, and with distinctly curved distal tips.

Accessory organ provided with a stylet 16–20 μm long it opens through its own pore.

Female genital system. Ovaria and vitellaria as in the previous species. With a spheroidal bursa in front of copulatory bulb, with external vagina ( Fig. 4 A ). Female pore just posterior to accessory organ pore.

Karyotype. With n=3, and basic karyotype for the Monocelididae ( Curini-Galletti & Martens, 1990) ( Fig. 5 E ). Chromosome pairs I and II not markedly differing in length. Karyotype formula: FN=5; Chromosome I: 42.85 ± 3.01; 47.64 ± 1.17 (m); Chromosome II: 37.43 ± 2.55; 43.79 ± 1.26 (m); Chromosome III: 19.75 ± 0.98; 10.97 ± 2.98 (a) (based on 7 plates).

Diagnosis. Species of Duplominona with up to 30 testes in two rows. Proximal spines of cirrus needle-shaped, up to 6 μm long; medially, spines are longer, to 15 μm long; distal spines shorter, 3.5–4 μm long, wider, and with curved distal tips. With a prostatoid organ provided with a stylet 16–20 μm long. With a round bursa in front of the copulatory organ, and an external vagina. With four distinct genital pores. Karyotype with two pairs of metacentric and one pair of smaller heterobrachial chromosomes.

Figures

FIGURE 4. Duplominona dissimilispina n. sp. (A) Habitus of a living animal; see Fig. 1 for interpretation of anatomical features. (B) Reconstruction of an inverted cirrus showing the sclerotised copulatory structures. (C, D, F) Micrographs of inverted cirri from karyological slides (C: Holotype; D, F: Paratypes). (E) Micrograph of a metaphasic plate. (Scale bars: B–D, F =10 m; E = 5 m).

FIGURE 5. (A–C) Duplominona chicomendesi n. sp. (A) Habitus of a living animal; see Fig. 1 for interpretation of anatomical features. (B) Reconstruction of the inverted cirrus showing the sclerotised copulatory structures. (C) Micrograph of the inverted cirrus (Holotype). (D–G) Duplominona diademata n. sp. (D) Micrograph of a metaphasic plate. (E) Habitus of a living animal; see Fig. 1 for interpretation of anatomical features. (F, G) Reconstruction (F) and micrograph (G) of the inverted cirrus of the Holotype. (Scale bars: B–D = 5 m; F, G = 10m).