Contributions to Zoology, 78 (3) - 2009Valentina Delogu; Marco Curini-Galletti: The Parotoplana jondelii species-group (Platyhelminthes: Proseriata): a microturbellarian radiation in the Mediterranean

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Parotoplana pulchrispina sp. n.

(Figs 3L; 4I)

Holotype: one karyological slide made permanent with lactophenol (SMNH 7571).

Type locality: Le Bombarde beach, Alghero (Sardinia, Italy) (lat. 40°35’1.50”N, long. 8°15’38.05”E), in medium-fine sand, about 2 m deep, May, December 2008.

Additional material: two karyological slides made permanent with lactophenol (CZM 178-179) and one specimen sagittally sectioned (CZM 180), all from the type locality.

Etymology: the name refers to the graceful, elegant morphology of the spines (latin pulcher = fine, beautiful).

Description: The sclerotised apparatus consists of numerous spines (21 in the holotype, 20 in CZM 178 and 22 in CZM 179).

- dorsal pairs D1 : two thin, needle shaped spines, 52-53 µm long in the holotype (range: 46-53 µm); stem 2-3 µm wide; D2 : two broad, straight spines, tapering into an acute point, 55-56 µm long in the holotype (range: 51-56 µm); stem 4-5.5 µm wide in the middle, and about 3 µm at its basis.

- Girdle: G1 -G6 : A somewhat variable number of similar, straight spines (11 in the holotype, 12 in CZM 179, 10 in CZM 178), ranging 42-54 µm in length in the sample, with slightly falcate apex, ending into an obtuse distal tip, and narrow, upturned subterminal apophyses, 2-5 µm long. Stem width ranging 1.5-2.5 µm; G7 : a pair of spines with straight, pointed apex, and very small apophysis inserted at about 14 µm from the distal tip. 49-50 µm long in the holotype (range: 50-53 µm); stem 3-3.5 µm wide in the middle, about 1.5 µm at its basis; G8 : very similar to G7 , but with more acute and slender, comparatively shorter (about 10 µm long) apex. 44-46 µm long in the holotype, ranging 44-51 µm in the whole sample; stem 3-3.5 µm broad.

- V: medially to pair G8 , all specimens had a pair of smaller spines, similar in morphology to G2 -G7 spines, but with straighter distal tip, and with very small, obtuse apophyses. In the holotype, these spines are 42-46 µm long, with a thin and feebly sclerotised stem. In the rest of the sample, they are about 46 µm long, with a stem slightly widening towards its base, which is 3 µm across.

Without bursal spines.

Karyotype. Chromosome number: n = 6; FN = 10. The first three pairs of chromosomes are distinctly larger than the three remaining pairs. Karyometrical data (based on measurements of four plates): Chrom. I = r.l.: 25.23 ± 1.19 ; c.i.: 42.45 ± 1.33 (m); Chrom. II = r.l.: 24.89 ± 0.06; c.i.: 38.01 ± 1.46 (m); Chrom. III = r.l.: 24.02 ± 1.24; c.i.: 32.5 ± 1.77 (sm); Chrom. IV = r.l.: 8.39 ± 0.65; c.i.: 15 ± 4.36 (st); Chrom. V = r.l.: 8.13 ± 0.98; c.i.: 36.43 ± 2.88 (sm); Chrom. VI = r.l.: 7.68 ± 0.74; c.i.: 11.3 ± 4.41 (t); haploid genome length: 10 ± 1 µm.