Parotoplana terpsichore, Delogu, Valentina & Curini-Galletti, Marco, 2007

Delogu, Valentina & Curini-Galletti, Marco, 2007, New species of the genus Parotoplana Meixner, 1938 (Proseriata, Otoplanidae) from southern Apulia (Italy), Zootaxa 1529, pp. 17-31 : 24-26

Parotoplana terpsichore sp. n.

( Figs. 4 A–B; Fig. 7 D)

Holotype: one whole mount ( SMNH 6665).

Type locality: Apulia, Italy: Porto Cesareo (Lecce), in front of the harbour (lat. 40°14’59.44”N, long. 17°53’31.22”E), about 22 m deep, medium-fine sand, May 2005.

Etymology: the specific epithet refers to the muse Terpsichore , usually portrayed as playing a lyre, similarly shaped to the sclerotized organs of the new species.

Description. Limited observations could be performed on the only specimen found. Size, general morphology of the body and arrangement of organs, similar to the other species of the genus ( Fig. 4 A). With two rows of testes (8-9 in each row) anterior to the ovaries, and numerous vitellaria in two rows posterior to the ovaries and extending laterally from the pharynx to the genital organ. A bursa filled with sperm could be observed.

With an ovoid seminal vesicle, and a comparatively short prostatic vesicle, connected to the sclerotized apparatus, consisting of numerous (48) spines ( Figs. 4 B; 7 D) which can be classified into four groups:

1) four median, nearly straight, broad spines ranging 86–90 µm, narrowing distally and provided with acutely pointed apices;

2) two groups of nine spines each, placed laterally to the previous spines, with acutely pointed apices, without a subterminal tooth. In each group, the most proximal spines are shorter (about 70 µm long). They progressively become longer (up to 83 µm long), narrower, and straighter laterally;

3) two groups of 12 spines each, lateral to the previous. In each group, the spines are arranged into a girdle, with the six most proximal spines (about 67 µm long), provided with very elongate, sickle shaped apices, and a distinct subterminal tooth, and the six marginal spines (about 60 µm long), provided with a shorter apex;

4) two additional spines appear placed above all the others. These are 68 µm long, straight, and as broad as the median spines. Their apex forms a spike, and is provided with a distinct subterminal tooth.

Remarks. Although only one specimen of P. terpsichore sp. n. has been found, its features were nonetheless so distinctive as to warrant a species description. The complex, sclerotized structures of the new species appear comparable uniquely to that of the western Mediterranean P. multispinosa (cf Ax, 1956, Fig. 173, pg.

232). Both species show a very large number of spines (48 in P. terpsichore sp. n., 38 in P. multispinosa ) and a similar general arrangement of the copulatory structures, but differ in details of spination. In P. multispinosa , the median spines consist of one larger, (78 µm long), and one smaller, straighter and narrower pair, (60 µm long). Furthermore, in this species there is no distinction in size and morphology of the lateral spines (groups 2 and 3 in P. terpsichore sp.n.), which all have sickle shaped apices with a subterminal tooth. The two additional spines are comparatively much longer, about 76 µm long.

Diagnosis: Parotoplana with a sclerotized apparatus consisting of four median, nearly straight, comparatively broad spines (86–90 µm long); two groups of nine narrower spines each, symmetrically arranged laterally to the previous, without subterminal tooth and becoming straighter laterally; two further groups of 12 spines each with sickle-shaped apex and a subterminal tooth (60-65 µm long), and two straight spines, 68 µm long, placed above all the others, with pointed apex and a subterminal tooth.

In addition to the previous species, two specimens of problematic identification were found:

Figures

FIGURE 4. Parotoplana terpsichore sp. n. A, General organisation of a live animal. Scale = 300 µm. B, Sclerotized apparatus.

FIGURE 7. Parotoplana jondelii sp. n. A, Sclerotized apparatus (holotype). Scale = 30 µm. B, Bursal spines (holotype). Scale = 30 µm. Parotoplana sp. A. C, Sclerotized apparatus (CZM 57). Scale = 30 µm. Parotoplana terpsichore sp. n. D, Sclerotized apparatus (holotype). Scale = 30 µm. Parotoplana sp. B. E, Sclerotized apparatus (CZM 58). Scale = 30 µm.