Notobryon bijecurum Baba, 1937

Description

A dendronotid about 30 mm in length. The head is expanded into a semicircular veil with a wavy margin. The rhinophore sheath has a posterior longitudinal crest and ends distally in a wavy margin. There are two pairs of dorso-lateral lobes, the posterior pair decidedly smaller than the anterior; the lobe margins are apparently entire. The tail crest is moderately large with an entire margin. Branchial tufts are large and dendritic, four on each dorso-lateral lobe and one on the hinder end of the back. A row of small conical tubercles runs along each side of the body. The genital orifice lies as usual on the right neck; the anus opens on the same side between the two dorso-lateral lobes; the nephroproct is just above the anus. The foot is narrow but expansible, abruptly rounded in front and continued into a tail behind. In life the body is yellow with bold opaque white markings on the back and sides.

Distribution

Type locality: Amadaiba, Sagami Bay, Japan (about 91 m depth).

Etymology

The specific epithet bijecurum is the neuter of a Latin compound from bi- ("two") and jecur ("liver"), meaning "with a two-lobed liver", referring directly to the diagnostic two-lobed liver of the species.

Remarks

Distinguished from the type species of Notobryon (Notobryon wardi) by (1) the markedly unequal dorso-lateral lobes, with the posterior pair decidedly smaller than the anterior, and (2) the two-lobed liver.

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References

• Notobryon bijecurum, Baba, K. 1937i. Two new species of the nudibranchiate genus Notobryon from Sagami Bay, Japan. Venus 7(4):165-170.
• ウミトンボ, Baba K. (1949). Opisthobranchia of Sagami Bay collected by His Majesty the Emperor of Japan (相模湾産後鰓類図譜). Iwanami Shoten, Tokyo. 4+2+194+7 pp., pls. 1-50.
• ウミトンボ, 中野理枝. (2004). 本州のウミウシ. ラトルズ.
• ウミトンボ, 小野篤司 & 加藤昌一. (2009). ウミウシ. 誠文堂新光社.
• ウミトンボ, 中野理枝. (2018). 日本のウミウシ. 文一総合出版.