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Pelican Flounder
Chascanopsetta lugubris lugubris Alcock, 1894
A 12 cm long larval Pelican Flounder (AMS I.39460-001). When alive, the white areas were transparent. Photo: C. Bento © Australian Museum. View larger image.
An adult Pelican Flounder.
The upper image shows a 12 cm long larval flatfish that was sent to the Australian Museum for identification by commercial fisherman, S. Chalker of Tuncurry. The fish was found inside the gut of a Lancetfish, (probably Alepisaurus ferox Lowe, 1833), which was captured on a longline near Lord Howe Island, 700 km off the New South Wales coastline.
The fish was sent on loan to Dr A. Fukui, (School of Marine Science and Technology, Tokai University, Japan), who identified it based on fin ray counts, pigmentation and its large size. As part of his work on this fish, Dr Fukui cleared and stained the specimen (see image below). Clearing and staining involves clearing the flesh, staining the bones red and the cartilage blue. This technique is particularly useful for examining the structure of the skeleton.
Most people are familiar with the flatfishes (flounders, soles etc). These fishes are very compressed, bottom-dwellers that have both eyes on the same side of the head. The larvae are also compressed, but unlike the adults, they are pelagic and have eyes on either side of the head. Only one pigmented eye is visible in the upper image (upper arrow). The other circular area is an air bubble trapped below the operculum (gill cover). The details are easier to see using the larger image link above.
The large orange loop is the gut of the fish. The anus lies at the end of the projection of the gut at the lower left of the loop (lower arrow). Many larval fishes have guts that extend beyond the margin of the body. Close to the time that the Pelican Flounder larva settles on the bottom, the right eye migrates to the left side of the head, the gut retracts within the abdominal cavity and the transparent body takes on a mottled appearance.
This Pelican Flounder has one of the largest larvae of any flatfish, however the adult only grows to about 38 cm in length. The larvae of some other flatfish species settle at as little as 1 cm in length. The largest flatfish adult is the Atlantic Halibut, Hippoglossus hippoglossus, which grows to 2.5 m.
This species has a wide distribution in the Indian and western Pacific Oceans.
Related links
- larval pelican flounder fact sheet
- Shortsnout Lancetfish fact sheet
- View the Family Bothidae list
- View the Flatfishes list
Further Reading
- Fukui, A. 1997. Early Ontogeny and Systematics of Bothidae, Pleuronectoidei. Bull. Mar. Sci. 60(1):192-212.
- Fukui, A. 2001. Larva of Chascanopsetta lugubris lugubris (Bothidae) disgorged by lancetfish (Alepisaurus sp.). Ichthyological Research. 48:100-103.
- Leis, J.M & T. Trnski. 1989. The Larvae of Indo-Pacific Shorefishes. NSW University Press. Pp. 371.
