Julia zebra Kawaguchi, 1981

Description

A tiny bivalved sacoglossan, reaching only about 5 mm in shell length. The body is green, with light brown markings on the head and rhinophores. The calcified, hinged pair of shells is also green, with fine brown radiating lines running from the umbo to the ventral margin — the namesake "zebra" striping. The shell is slightly concave below the umbo, and the rhinophores are rolled into a tube.

Distribution

Originally described from Mishima and Tsunoshima (Yamaguchi Prefecture, Japan) and Ishigaki Island (Okinawa Prefecture, Japan). Subsequently recorded across the Indian Ocean, Japan, and the central and south Pacific, with sightings reported from Hawaii, Midway Atoll, Cook Islands (Rarotonga), and South Africa.

Etymology

The specific epithet zebra refers to the zebra-like radiating striping on the shell.

Remarks

A herbivorous sacoglossan that despite the bivalved appearance is a gastropod; it feeds on green algae. Recent molecular analyses suggest that Julia zebra as currently circumscribed is likely a complex containing more than one cryptic species.

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References

• Julia zebra n. sp., Kawaguti S. (1981). A new bivalved gastropod, Julia zebra n. sp. Bulletin of Kawasaki Para Medical College. 1: 9-13.
• ゼブラユリヤガイ, 川口四郎. (1983). 二殻腹足類ユリヤガイ. 川崎医療短期大学紀要. 2: 93-100. https://doi.org/10.18928/00000643
• Julia zebra, McCarthy-Taylor J.B., Krug P.J., Muro S., Vendetti J., Maestrati P., Wong N.L.W.S., Gosliner T.M. & Valdés Á. (2025). The slug within the bivalve: molecular and morphological systematics of the family Juliidae (Gastropoda: Panpulmonata: Sacoglossa). Zoological Journal of the Linnean Society. 204(2): zlaf056. https://doi.org/10.1093/zoolinnean/zlaf056