Duplominona diademata 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 : 136-137

Duplominona diademata Curini-Galletti n. sp.

( Fig. 5 D–G)

Holotype. Puerto Rico: Cayo Turrumote , off Isla Magueyes (Lat. 17.940478, long -67.043068), channels among Montastrea outcrops, at about 10 m of depth, in silty medium sand, December 1988: original film and printed pictures of the copulatory structures (SMNH-Type 9180).

Other material. Same data as holotype, one specimen observed alive, and used for karyology.

Etymology. From Latin diademata : adorned with a diadem.

Description. Smaller and more slender than the previous three species, without clusters of rhabdoids ( Fig. 5 E ).

Male genital system. With 10–15 testes, arranged into a single, median row. Copulatory organ comparatively small, ovoid, with a clearly distinct prostatic vesicle. Cirrus with two spiny areas, separated by an intermediate area, totally devoid of spines ( Fig. 5 F, G ):

1) proximally, an area about 25 μm long is provided with about 10 rows of densely packed needle-shaped spines. Most proximal spines are longer, to 10 μm; spines decrease in size distally, to about 7 μm in length.

2) a distal corona, most often partly everted, of 5–7 rows of densely packed spines. The spines basal to this area are hard to discern. They appear to be about 7 μm, with a hooked distal tip. Distalmost spines are straight, needlelike, to about 13 μm in length.

Prostatoid organ provided with a stylet about 16 μm long; it opens through its own pore. Female genital system. Ovaria and vitellaria as in previous species. With a spheroidal bursa with external vagina. In living specimens, distances b:c:d appear to be nearly equal; vaginal pore much closer to male pore than to mouth.

Karyotype. With n=3, and basic karyotype ( Curini-Galletti & Martens, 1990). Chromosome pairs I and II markedly differing in length ( Fig. 5 D ). Karyotype formula: FN=5; Chromosome I: 50.58 ± 2.76; 45.97 ± 1.65 (m); Chromosome II: 34.92 ± 1.99; 45.74 ± 1.27 (m); Chromosome III: 14.5 ± 1.56; 9.51 ± 2.15 (a) (based on 6 plates).

Diagnosis. Species of Duplominona with up to 15 testes in one row. Cirrus with two spiny areas, separated by a median area without spines. Spines in proximal area are needle-shaped, 7–10 μm long; Spines in the distal area range from hook-shaped to needle-shaped, to 13 μm long. Prostatic stylet about 16 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 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).