Polycarpa zorritensis ( Van Name, 1931 )

Monniot, Françoise, 2016, A new species of Polyandrocarpa (Ascidiacea, Styelidae) in the Mediterranean Sea, Zootaxa 4132 (1), pp. 87-96 : 91-93

Polycarpa zorritensis ( Van Name, 1931)

Figures 3–7 .

P. zorritensis first described from Peru ( Van Name 1931) is also recorded from California ( Lambert & Lambert 1998, 2003), Brazil ( Millar 1958), Florida ( Vazquez & Young, 1998) and Japan ( Nishikawa et al 1993) ( Fig. 5 ). Several specimens from these records are present in the MNHN collection and have been examined. In the Mediterranean this species was noticed for the first time from Italy (Brunetti 1978–1979) and later on the Spanish coast ( Turon & Perera 1988) and more recently considered as common in several shallow Mediterranean areas ( Brunetti & Mastrototaro 2004).

The description below is made after dissections made on the material from Tarento ( Italy) kindly sent by F. Mastrototaro, and corresponds to observations on other material already published. The individuals are elongated with both siphons anterior, parallel to each other, with their tunic linked in a common thick basal sheet ( Fig.3 A), or sometimes by basal stolons. The tunic is thin but resistant without sand. The organs are visible through the thin translucent body wall ( Fig.3 B). The oral tentacles are well spaced in 2 orders of size behind a velum. (( Fig.4 AB.). The prepharyngeal band is double. The dorsal tubercle is a button-like transverse opening. There are 4 complete branchial folds ( Fig. 4 B). The spaces between the branchial folds contain fewer longitudinal vessels than in P. arianae , one or 2 as described by Van Name (1931), and the parastigmatic vessels are generally absent except when a row of stigmata is dividing ( Fig. 4 D). The first right fold moves apart from the dorsal lamina posteriorly, leaving a triangular space. The primary gut loop is short and closed with a plicate stomach which possesses a caecum. The rectum is long ( Fig. 4 A,C) and the anus has 2 lips one of which is lobed. A foliated endocarp occupies the primary gut loop ( Fig.4 AC). The round polycarps are placed in a single straight line on each side of the endostyle and close to it ( Fig. 4 A,C). The sperm duct of each testis lobe is independent from the others; they all join at the single distal male papilla which opens at some distance from the wide open female papilla ( Fig. 3 C). The Italian specimens do not contain embryos in incubation.

Other samples of P. zorritensis present in the MNHN collection from distant regions were also examined, all collected at the shore or in marinas. All have a similar size and colony shape ( Fig. 5 ). Specimens from the type colony from Peru, others from Florida: Fort Pierce ( Fig. 5 B, 6A,B), from Brazil: Rio ( Fig. 5 A,.6C), from California: Oceanside ( Fig. 5 C, 7 A,B) and Japan: Kochi ( Fig. 5 D, 7C,D,E) have all the same anatomy. Some constant characteristic features can be noticed that are independent of the specimen size. The dorsal lamina is always displaced to the left side and joins posteriorly the first branchial fold on the left; there are no parastigmatic vessels. The most ventral branchial fold on each side is always smaller than the others. The secondary gut loop is absent or poorly curved; there is a gastric caecum and an endocarp in the gut loop.

Figures

FIGURE 3. Polyandrocarpa zorritensis. A, part of a colony; B zooid extracted from the tunic; C, three polycarps. Scale bars: A = 1 cm; C = 5 mm.

FIGURE 4. Polyandrocarpa zorritensis from Tarento, Italy. A, dissection and B, branchial sac of a same zooid; C, dissection and D, part of the branchial sac of another zooid. Scale bars: A, B, C = 5 mm.

FIGURE 5. Polycarpa zorritensis colonies: A, from Brazil; B, from Florida; C, from California; D, from Japan. Scale bars: A = 5 mm; B, C, D = 1 cm.

FIGURE 6. Polycarpa zorritensis. A and B, branchial sac and body of a zooid from Florida. C, specimen from Brazil ventrally opened showing incubated embryos. Scale bars: A, B, C = 2 mm.

FIGURE 7. Polycarpa zorritensis. A and B, body and branchial sac of a zooid from California; C, D and E, body, polycarps and branchial sac of a zooid from Japan. Scale bars: A, B = 5 mm; C = 4 mm, E = 2 mm.