Author: (Eliot, 1904)

Order: Nudibranchia  Family: Facelinidae

Maximum Size: 20 mm

Sightings: Sunshine Coast

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Cratena lineata (Eliot, 1905)

Cratena lineata is well known in the Indo-Pacific region. It is a small aeolid nudibranch growing to 20 mm in length, though most usually sighted in the 10 to 12 mm range. The body is narrow and translucent, sometimes with a light brownish tint and with some of the internal organs visible. It finishes posteriorly in a long tapering tail. There are well delineated lines of white pigment running longitudinally on the notum. Having said that, there are reports of specimens lacking these white lines. The rhinophores are tall, smooth and tapered, and may be translucent or watery orange on the basal half but bear opaque white pigment on the distal half. The oral tentacles are similarly coloured and slender but of twice the length of the rhinophores. There are two orange/red patches below and anterior to the rhinophores on the “cheeks” a quite common feature in Cratena species. The cerata are arranged in 5 to 6 groups down each side, laterally on the notum. There is a gap over the pericardium between the first group (pre-pericardial) arranged in an arch and the second (post-pericardial) and following groups arranged in simple rows. The number of cerata in each group may decrease towards the posterior end. The cerata bear similar white lines as the notum over translucent colouration allowing the dark brown slightly wrinkled branches of the diverticulum to show through. Those white lines may be more concentrated on the tips. The basal portion, up to half or even more, of the diverticula within the cerata may be of a deep red colour in some specimens. The foot is narrow but well-developed anteriorly into tentacular corners (propodial tentacles).

Cratena lineata feeds on hydroids upon which it also lays its white or apricot coloured spawn, attached in a zigzag manner along the hydroid branches.

Distribution is reported to be wide-spread in the Indian and western Pacific Oceans even along the southern coastline of Australia..

This species was described by the diplomat and colonial administrator Sir Charles Eliot, the Commissioner for the East African Protectorate (Kenya & Zanzibar) at that time.

Originally described as Hervia lineata.

References:
– Eliot, C.N.E. (1905). On some nudibranchs from east Africa and Zanzibar. Part VI. Proceedings of the Zoological Society of London, 1904(2): 268-298, Pls. 16-17.

– Edmunds, M. (1970). Opisthobranchiate Mollusca from Tanzania. II. Eolidacea (Cuthonidae, Piseinotecidae and Facelinidae). Proceedings of the Malacological Society of London 39: 15-57.

– Burn, R. (2006). A checklist and bibliography of the Opisthobranchia (Mollusca: Gastropoda) of Victoria and the Bass Strait area, south-eastern Australia. Museum Victoria Science Reports 10: 1-42 (2006).

– This Species Profile has been modified from a previously published article in Dive Log Magazine’s – Critter ID with NudiNotes Column, Issue: #372 (July 2019): 12 by David A. Mullins

David A. Mullins, July 2019