Leptoclinides planus, Monniot, 2010

Monniot, Françoise, 2010, Some new data on tropical western Pacific Ascidians, Zootaxa 2561 (1), pp. 1-29 : 13-14

Leptoclinides planus n. sp.

( Figures 14 , 15 )

Material. Coll. P.L. Colin, Vanuatu: Espiritu Santo, Aore Island , 15°33.24’S – 167°09.50’E, 18m, 01/XII/ 2000, CRCHO 457 ( MNHN A2 LEP 116 ) .

The colonies are large flat crusts 3mm thick. An orange colour was noted by the collector. The density of spicules makes the surface layer raspy. The colonies are tough and can be easily removed from the substrate. The narrow cloacal channels are limited to the thoracic level. The zooids are difficult to extract from the tunic. The thorax (14A), about 0.5 mm long, has a cylindrical oral siphon with a smooth edge: a strong sphincter encloses its base. The atrial siphon is tubular originating at mid-length of the thorax its rim dorsally expanded in a point. The stigmata could not be counted in the adult thorax but 7 to 8 stigmata can be seen in the first row of larval oozooids ( Fig. 14B ). The waist is particularly long. The abdomen is pear shaped, included in the basal tunic which also contains larvae and some brown organic inclusions. The gut loop is flat. A single testis lobe ( Fig. 14D ) is circled with 4 turns of the sperm duct. In some zooids the sperm duct is clockwise coiled, in some others two testes with their own sperm duct are placed close to each other ( Fig.14C ).

The larvae 0.7mm in length have 3 adhesive papillae, with long stems, sided by 3 vesicles on each side plus one vesicle dorsal and one ventral ( Fig. 15B ). The larva is well developed with 4 rows of stigmata and the abdomen is sketched. The tail is wound in ¾ of a turn.

The spicules ( Fig. 15A ) are stellate with short chisel-shaped rays coming out from a dense central mass. Their diameter is 0.07mm.

Leptoclinides species having a single testis vesicle are not numerous worldwide:

L. aspiculatum Romanov, 1989 , from the Japan Sea, is devoid of spicules

L. capensis Michaelsen, 1934 from South Africa and Kerguelen, has a larva 1.5mm long.

L. faeroensis Bjerkan, 1905 from Iceland, has a larva 1.2mm long with 4 pairs of vesicules lining the adhesive papillae.

L. fungiformis Kott, 1972 , from South Australia has pedunculate colonies.

L. macrotestis Romanov, 1977 , from Behring Sea, has numerous turns of the sperm duct

L. unitestis Monniot F., 1989 from New Caledonia, differs in several points; the spicules are larger with fewer rays, the oral siphon has 6 pointed lobes and the cloacal siphon is shorter. The larva 1.4mm long has about 12 stigmata in the first row.

Figures

FIGURE 14. Leptoclinides planus: n. sp. A: thorax, B: larva, C: abdomen with an additional testis, D: abdomen with a single testis. Scale bars 0.5mm.

FIGURE 15. Leptoclinides planus n. sp.: A: spicules, B: larva. Scale bars: A=10µm, B=0.5µm.