Pseudominona, Karling, 1978

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

Pseudominona cf dactylifera Karling, 1978

( Fig. 7 )

Material examined. Puerto Rico: Cayo Corral, off Isla Magueyes (Lat. 17.936739, Lon. -67.019831), intertidal, in poorly sorted granule, December 1988. One specimen observed alive and used for karyology ( CZM 808 : original film and printed pictures of the copulatory structures)

Description. A comparatively robust animal, about 2 mm long, with a tripartite caudal area ( Fig. 7 A ). With a narrowly elongate cirrus, made up with a large number of triangular spines. Bermuda specimens were described with spines all alike, 2–4 μm, acutely triangular. From the picture given, however, it may be noticed that distalmost spines appear to be curved, with a wide basis ( Karling, 1978, fig. 19, p 230). The Puerto Rican specimen had a long cirrus, over 200 μm long, with about 50 rows of acutely triangular spines ( Fig. 7 B, C, E ). Proximal spines are about 2–3 μm long; they become longer and more narrow distally, up to 12 μm long, and 2 μm wide at basis. Distalmost spines are shorter (3–7 μm), curved, and with wider basis, very similar to the picture of the Bermudian specimen. With a large accessory stylet, about 30 μm long ( Fig. 7 D ). It is about 23 μm in specimens from Bermuda.

Female system with post-pharyngeal ovaria, and very short oviducts entering a large sphaeroidal bursa. The very long vaginal duct runs backwards and opens to the outside through an external vagina posterior to the copulatory organ, in front of the accessory organ ( Fig. 7 A ).

Karyotype. With n=2 ( Fig. 7 F, G ). Karyotype formula: FN=3; Chromosome I: 64.98 ± 1.9; 46.89 ± 1.04 (m); Chromosome II: 35.02 ± 1.9; 13.86 ± 3.04 (st)(based on 12 plates).

Remarks. Based on Karling’s (1978) description of Bermudian specimens, differences in the morphology of sclerotized structures may justify a distinct species-status for the Puerto Rican specimen. However, nothing is known about intra-population variability of the cirrus both in Bermuda and Puerto Rico, and a detailed description of the cirrus of Bermudian specimens is lacking. On the basis of available information, no further speculation of the status of the Puerto Rican specimen is thus possible.

Figures

FIGURE 7. Pseudominona cf dactylifera Karling, 1978. (A) Habitus of a living animal; see Fig. 1 for interpretation of anatomical features. (B–D) Reconstruction (B) and micrographs (C, D) of the inverted cirrus. (E) Micrograph of the stylet of the accessory organ. (F, G) Micrographs of metaphasic plates. (Scale bars: A–E =10 m; F, G = 5 m).