The “leaf-sheep-nudibranch”-Costasiella kuroshimae
The leaf-sheep snail or in the technical language Costasiella Kuroshimae lives on a subject algae called “Avrainvillea”, which comes on fine-grained to muddy soil in shallow and wave protected areas up to a depth of 30 meters. The mainly green-brown coloured algae is mostly wedge-shaped to rounded, it is the food basis for the leaf-sheep-snail, which uses the chloroplasts of the algae for photosynthesis (Kleptoplastie). Because of this, it is usually found in depths of 5-15 meters. It is also often referred to as “solar energy operated”. In addition to this ability, it is visually special, many also compare it to the cartoon character “Shaun the Sheep”.
Due to its exceptional appearance, the snail is also extremely popular with photographers and is also one of the most demanding animals under water. For one thing, this is because it is very difficult to find and, on the other, its small size of only 2-7mm. A macro lens with a large focal length (> = 90mm at full frame) and an additional macro lens such as the Nauticam SMC-1 or Aquako IV with a strong magnification are a prerequisite to be able to properly illuminate the leaf-sheep-worm. Likewise, one should have patience and a steady hand, 10 minutes and more for a single picture are not uncommon, since the subjects algae also with the slightest movement of the water with moves (even with hand movements and even more in fin strokes) and since the worm itself On direct stronger light, as if by a focus light, responds with escape. Luckily, it doesn’t do this very fast, the low depth of focus despite the closed aperture and the barely available room for focusing, however, ensure that you often only see it from behind.
All pictures shown here were taken on our last trip to the Prince John Dive Resort in Sulawesi, Indonesia. There you can find them at three different dive sites: Jetty, Loli I and Loli II.
Overview
Scientifically: Costasiella Kuroshimae Colloquially speaking: Leaf sheep Snail English: Leaf Sheep Nudibranch Family tree: Animalia (Realm) > Mollusca (root) > Gastropoda (Class) > Sacoglossa (okay) > Costasiellidae (family) > Costasiella (genus) > Kuroshimae (ART) First determination: Ichikawa, 1993 Occurrence: Indo-Pacific, Japan, Komodo, Mozambique, Okinawa, Papua New Guinea, Western Pacific Size: 2-7mm
