Didemnum duplicatum Monniot F. 1983

Monniot, Françoise, 2016, Ascidians (Tunicata) of the French Guiana Expedition, Zootaxa 4114 (3), pp. 201-245 : 206-207

Didemnum duplicatum Monniot F. 1983

Figure 4 A.

Stations. SR5; SS4.

Recorded from Caribbean islands ( Monniot F. 1983), Texas ( Lambert et al 2005) and North Carolina (G. Lambert unpublished) this species may be misinterpreted as D. galacteum having similar colonies. The differences in the zooids are difficult to evaluate, the oral siphon in D.duplicatum is wider and thicker. There is no atrial languet. The lateral thoracic organs are protruding at the level of the third stigmatal row. The testis is divided into 2 lobes very flat and tightly applied on the gut loop. The larva is the essential difference between both species In D. duplicatum there are 8 pairs of ectodermal ampullae around the three adhesive papillae ( Fig. 4 A) and the larval body 0.9mm long has no bud. The spicules as figured in Monniot F. (1983 pl.1E) have few rays of blunt rods themselves made of parallel fibres.

Figures

FIGURE 4. Didemnid larvae stained with hemalum. A, Didemnum duplicatum; B, Didemnum galacteum; C, Didemnum psammathodes; D, Polysyncraton amethysteum. Scale bars: A = 0.5 mm; B = 0.3 mm; C = 0.2 mm; D = 0.4 mm.