Polyzoa opuntia Lesson, 1830,

Turon, Xavier, Cañete, Juan I., Sellanes, Javier, Rocha, Rosana M. & López-Legentil, Susanna, 2016, Ascidian fauna (Tunicata, Ascidiacea) of subantarctic and temperate regions of Chile, Zootaxa 4093 (2), pp. 151-180: 171-172

publication ID

http://doi.org/10.11646/zootaxa.4093.2.1

publication LSID

lsid:zoobank.org:pub:ECC66298-6885-47B3-B797-8D30AA05927F

persistent identifier

http://treatment.plazi.org/id/03C88E54-FF8D-FFA6-FF77-B6E0FBDF33D2

treatment provided by

Plazi

scientific name

Polyzoa opuntia Lesson, 1830
status

 

Polyzoa opuntia Lesson, 1830 

Fig. 12View FIGURE 12

References and synonymy: Polyzoa opuntia Lesson  (1830 b) p. 437; Van Name (1945) p. 236; Kott (1969) p. 100; Monniot (1970) p. 344; Polyzoa reticulata Van Name (1945)  p. 237; Kott (1969) p. 102.

Localities: 1 S, 2 S, 4 S, 7 S, 8 S, 9 S.

This colonial species is very abundant on the artificial substrates surveyed in the Punta Arenas zone. Typically, it forms stalked colonies up to 20 cm in length and of different shapes, the larger ones being normally elongated and flattened, the smaller cylindrical or simply conical. The colour in general is reddish, although a yellow form has also been found in Cabo Negro docks (locality 7 S). In the colonies the zooids are united forming a compact mass where the zooids are encased. Convex protuberances with siphons mark the different zooids from the outside. However, the species can also form investing colonies with zooids clustered closely together, or with zooids completely separated linked only by stolons.

Each cylindrical zooid can measure up to 10 mm in length, with the siphons at the apical end and, in the case of compact colonies, one or two stolons at the basal end entering the common tunic. Internally there are ca. 25 welldeveloped simple tentacles with intervening smaller ones. The aperture of the neural gland is an oblique slit. The branchial sac has 8 longitudinal vessels on each side and up to ten stigmata per mesh. The digestive forms a simple loop without secondary curvature. The stomach is folded, with a curved pyloric caecum. At the level of the caecum a strand of tissue connects the stomach with the intestine, bridging the primary loop. There is a row of hermaphrodite gonads at both sides of the endostyle (10–12 on the right, 6–8 on the left). The gonads are elongated, with a basal testis and some oocytes on top. There is a terminal female opening and a subterminal male papilla forming a slender tube. The right row of gonads curves anteriorly and dorsally in the posterior part of the body. Small endocarps are scattered at both sides of the mantle.

Remarks. the variability of colonial shapes, from clearly separated zooids to compact stalked colonies, is a characteristic of this species. The stolonial form with separate zooids has been known as Polyzoa reticulata (Herdman, 1886)  , but it was later revealed to be the same species (Monniot & Monniot 1978, 1983). It is abundant in the Magellan region and the South Georgia Islands (Monniot & Monniot 1983).

Kingdom

Animalia

Phylum

Chordata

Class

Ascidiacea

Order

Pleurogona

Family

Styelidae

Genus

Polyzoa

Loc

Polyzoa opuntia Lesson, 1830

Turon, Xavier, Cañete, Juan I., Sellanes, Javier, Rocha, Rosana M. & López-Legentil, Susanna 2016
2016
Loc

Polyzoa reticulata

Van Name 1945
1945