Trapania caerulea Gosliner & Fahey, 2008

Location: USAT Liberty Shipwreck, Tulamben, Pulau Bali, Indonesia
Date: 2018/01/13
Length: 10mm
Depth: 20.0m
Water temperature: 28.0℃

Description

Body 5–7 mm long, elongate and convex, lacking a notal margin. Widest at the branchial region. Oral tentacles are long with pointed apices. Rhinophores bear 9–10 lamellae and are slightly enlarged distally. Extra-rhinophoral and extra-branchial appendages are short and curved. Gill of three bipinnate branches.
The body is cream yellow with two brown lines extending from the rhinophore sheaths to both edges of the branchial shield, and a brown line along the lateral edge above the foot. A pale blue mid-dorsal line extends in front of the gill and bifurcates around it. Royal blue pigment covers the anterior surface of the foot and continues to the posterior tip behind the gill. Oral tentacles are reddish-brown with an irregular white blotch near the apices; anterior foot tentacles have reddish-brown tips. Extra-rhinophoral and branchial shields are creamy yellow; rhinophores are translucent white with red-brown edges and the gill leaves are red-brown.

Distribution

Known only from Bali, Indonesia (type locality: Tulamben).

Etymology

Verbatim from the original description (Gosliner & Fahey, 2008, p.62):

The specific name caerulea is taken from the Latin word for 'blue', to describe the unusual blue lines on the dorsum of this species.

Remarks

Described as one of 16 new Indo-Pacific Trapania species in Gosliner, T.M. & Fahey, S.J. 2008 Zoological Journal of the Linnean Society 152: 53-111. The authors stated: "Externally, this species does not closely resemble any other Trapania, either in its colouration or in the unusual form of the extra-branchial appendages. All other Trapania have elongate extra-branchial appendages. No other Trapania species has the distinct dorsal lines accompanied by a royal blue, mid-dorsal line that bifurcates around the gill" (p.63).