Thuridilla undula Gosliner, 1995

Description

Background colour turquoise bluish-green. The parapodial margin is lined with a broad undulating band of burnt orange. Below this is a narrow undulating black line, then an undulating region of vivid reflective blue pigment. The head has black and reflective blue pigment. The base of the rhinophores is the same colour as the body; the middle bears narrow undulating bands of blue and black, and the apex has a broad orange band. Orange, black and blue bands are also present on the anterior margin of the foot.

Distribution

Papua New Guinea, Guam, Palau, Philippines, Maldives.

Etymology

The specific epithet undula refers to the undulating bands along and below the parapodial margins.

Remarks

Most closely related to Thuridilla lineolata (Bergh, 1905); both species lack the expanded pharyngeal pouch found in some other clades. Thuridilla undula differs from Thuridilla lineolata in having highly ramified lateral pericardial vessels (only bifurcate in Thuridilla lineolata) and posterior vessels with a common junction prior to entering the pericardium (separate insertions in Thuridilla lineolata). Coloration is similar to Thuridilla neona, but in Thuridilla undula the orange/blue/black markings on the rhinophores are transverse bands (diagonal in Thuridilla neona), and Thuridilla neona has additional bright orange markings on the parapodia, anterior foot, and rhinophores.

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References

• Thuridilla undula sp. nov., Gosliner T.M. (1995). The genus Thuridilla (Opisthobranchia: Elysiidae) from the tropical Indo-Pacific, with a revision of the phylogeny and systematics of the Elysiidae. Proceedings of the California Academy of Sciences. 49(1): 1-54.
• ツリディラ・ウンドゥーラ, 殿塚孝昌. (2003). ウミウシガイドブック〈3〉. TBSブリタニカ.
• シラナミミドリガイ（新称）, 小野篤司. (2004). 沖縄のウミウシ. ラトルズ.