Placentela crystallina Redikorzev, 1913

Sanamyan, Karen & Sanamyan, Nadya, 2017, Shallow-water Ascidians from Matua Island (central Kuril Islands, NW Pacific), Zootaxa 4232 (3), pp. 301-321 : 310-312

publication ID

https://doi.org/ 10.11646/zootaxa.4232.3.1

publication LSID

lsid:zoobank.org:pub:F8F512BA-DD07-467E-B3C1-840155C70692

DOI

https://doi.org/10.5281/zenodo.6049280

persistent identifier

https://treatment.plazi.org/id/CC0787BC-FFD8-0708-6EDE-F9ACFC3EEECB

treatment provided by

Plazi

scientific name

Placentela crystallina Redikorzev, 1913
status

 

Placentela crystallina Redikorzev, 1913

( Figure 8 View FIGURE 8 )

Placentela crystallina Redikorzev, 1913: 212 . Nishikawa, 1984: 39. Sanamyan, 1998: 134. Homoedistoma michaelseni Redikorzev, 1927: 376 .

Material examined. Matua Island, Point Kluv, 16–17 m, collected at 25– 28.08.2016, three colonies (#153, 160, 169).

Description. All colonies are small, the largest is 3 cm long, and all are represented by a single head on rather high peduncle and contain from two to five zooids only. The most conspicuous part of colony is a transparent head containing thoraces of the zooids. In the head the zooids are oriented in such a way, that their branchial openings open on the sides of the head and the atrial openings open independently from each other closer to the top of the head ( Figure 8 View FIGURE 8 B). The atrial openings have six equal prominent round lobes, the branchial openings also have six lobes, but the dorsal lobe is larger than other, which are low.

The zooids are large and characteristic for this species. They have wide, but relatively short branchial sac with 10 rows of stigmata and about 40 stigmata per row on each side. The abdomen is very long, the stomach is in its posterior end which is filled by parenchymatous tissue. The postabdomen and gonads not present in the material examined, however several zooids contained larvae attached to a placental membrane in the right side of the thorax ( Figure 8 View FIGURE 8 C, D). The fully developed larva has a trunk 1.1 mm long. It has thee adhesive organs arranged in a vertical row and has no vesicles or ampullae ( Figure 8 View FIGURE 8 E).

Remarks. In the Sea of Okhotsk and in Kamchatka waters this species may form large, 20 cm and more, heavily branching, tree-like colonies, but all specimens recorded in Matua Island are very small, although some contain fully developed larvae.

The genus Homoedistoma Redikorzev, 1927 is a synonym, its type species, H. michaelseni Redikorzev, 1927 is conspecific with Placentela crystallina (see Sanamyan, 1993, type revision).

Kingdom

Animalia

Phylum

Chordata

Class

Ascidiacea

Order

Enterogona

Family

Polyclinidae

Genus

Placentela

Loc

Placentela crystallina Redikorzev, 1913

Sanamyan, Karen & Sanamyan, Nadya 2017
2017
Loc

Placentela crystallina

Sanamyan 1998: 134
Nishikawa 1984: 39
Redikorzev 1927: 376
Redikorzev 1913: 212
1913
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