Polyzoa atlantica Sanamyan, Gleason & Sanamyan, 2009, n.sp.

• Main Authors: Sanamyan, Karen, Gleason, Daniel F., Sanamyan, Nadezhda
• Format: Other/Unknown Material
• Language: unknown
• Published: Zenodo 2009
• Subjects: Biodiversity; Taxonomy; Animalia; Chordata; Ascidiacea; Pleurogona; Styelidae; Polyzoa; Polyzoa atlantica; Kamchatka
• Online Access: https://doi.org/10.5281/zenodo.6214136; http://treatment.plazi.org/id/635487A9B460AA4F538F1780114C1826

Polyzoa atlantica n.sp. (Figures 1–3) Material examined: Holotype: collected in 2004, at 31°36.056' N, 80°47.431' W, specimen #190, deposited in Kamchatka Branch of the Pacific Institute of Geography (KBPIG 1/1384). The colony consists of several ovoid or globular zooids 3–4 mm in diameter that are attached to the test of the solitary ascidians Molgula occidentalis Traustedt, 1882 and Styela canopus Savigny, 1816. The spacing between zooids is variable, zooids are never coalescent, and are attached by a small narrow surface on their posterior side (Figure 1 A, B). Zooids are connected only by inconspicuous thin sheet or stolons that are spread over the substrate. Each zooid has its own test covered completely with firmly attached sand grains (Figure 1 C). The zooids do not possess hair-like outgrowths. The siphons are not discernible on the preserved material and, as a whole, this sandy colony is very inconspicuous and difficult to detect. The body wall is thin, firm, and translucent. Body musculature consists of a rather irregular mesh of spaced longitudinal and circular fibers that are long and fine, but rather resistant. The branchial siphon opens approximately on the top of the zooid and the atrial siphon is displaced slightly downward along the dorsal side. Simple oral tentacles are rather long and robust; in two zooids about 10 larger tentacles were observed alternating with an equal number of smaller ones. The prepharyngeal band runs as a circular line without dorsal indentation around minute dorsal tubercle. The dorsal lamina is high and has a smooth margin. A flat branchial sac has only three internal longitudinal vessels on each side. Stigmata are in 12 transverse rows with 30–35 stigmata per row. Most stigmata are crossed by a rather thick parastigmatic vessel. As is common in many species of ascidians, the space between the endostyle and the most ventral longitudinal vessel is about two times wider than the space between adjacent longitudinal vessels. All stigmata are longitudinal (transverse ...