Fauna
Invertebrate · GBIF taxon 5859288

Little Leaf-sheep

Costasiella kuroshimae

Also known as Leaf Sheep, Leaf Slug, Kuroshima's Costasiella

Little leaf-sheep are tiny sacoglossan sea slugs that graze on marine algae and retain functional chloroplasts inside their leaf-like cerata, allowing them to draw supplemental energy directly from sunlight through kleptoplasty. Two dark bead-like eyes set closely between pale, scent-sensing rhinophores give them the comical appearance of a grazing sheep with a woolly coat of green succulents. They spend almost their entire lives moving slowly over host algae fronds, laying delicate spiral egg ribbons securely attached to the plant surface.

MarinePhotosyntheticTiny
Little Leaf-sheep reference1 / 3
Licensed reference(c) Pierre Pericard, some rights reserved (CC BY) · cc-by
—observations
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Not EvaluatedConservation statusIUCN Red List categoriesLCNTVUENCREWEXNot Evaluated — not placed on the risk ladderRed List categories, explained →
Key facts
Diet & prey
  • Avrainvillea algae
Predators
  • Carnivorous sea slugs
  • Small reef fish
  • Crabs
ThreatsHabitat destruction, ocean warming, siltation, and direct disturbance from diver photography
HabitatsShallow tropical coral reefs, sandy rubble, and calm sheltered lagoons
Life spanSeveral months to roughly 1 year
Classification
  1. FamilyCostasiellidae
  2. SpeciesCostasiella kuroshimae
Range & activity
Range data is not available yet.
Safe observation
Interaction riskLow
  1. Low
  2. Moderate
  3. High
  4. Very high
Why interaction risk is low
Safe to observe at a normal distance.
Responsible observation
  • Spotting Technique: Scan the upper surfaces of flat green Avrainvillea algae blades with a magnifying lens or macro dive light.
  • Buoyancy Control: Hover carefully well above the substrate to avoid stirring up sand or crushing their delicate algal hosts.
  • Macro Etiquette: Limit bright strobe flashes and never touch or reposition these microscopic animals for a photograph.
Related species
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