Nudibranchia

Nudibranchia, commonly known as sea slugs or nudibranchs, are a group of soft-bodied, marine gastropod mollusks that have no shell. They are found in all the world’s oceans, from the tropics to the polar regions. There are over 3,000 known species, and new species are being discovered regularly. Nudibranchs are incredibly diverse in their appearance, with a wide range of colors, patterns, and shapes.

Alison’s Jorunna – Jorunna alisonae

Leopard Jorunna – Jorunna pardus

Toyama Nudibranch – Janolus toyamensis

Nudibranch – Janolus mirabilis

Purple-crowned Sea Goddess – Felimare kempfi

Sphon’s Chromidorid – Felimida sphoni

Doubtful Facelina – Facelina dubia

Facelina olivacea

Favorinus vitreus

Japanese Favorinus, Egg-Eating Nudibranch – Favorinus japonicus

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Characteristics

Nudibranchs are characterized by their lack of an external shell, a feature that sets them apart from other gastropods. They have a unique respiratory system, relying on external gills called cerata. Cerata are often brightly colored and can be used for defense or to aid in respiration. Nudibranchs also have a pair of sensory organs called rhinophores, which they use to smell and taste their surroundings.

Environments

Nudibranchs are found in a variety of marine environments, including rocky shores, coral reefs, and kelp forests. They are primarily found in shallow water, but some species have been observed in deeper waters. Nudibranchs are carnivorous and feed on a variety of organisms, including sponges, hydroids, anemones, and other mollusks. Some species of nudibranchs can store toxins from their prey in their cerata, making them poisonous to predators.

Classification

Nudibranchia is a suborder of the order Nudipleura. This order, which includes the nudibranchs, contains the largest group of sea slugs that lack shells. Within the suborder Nudibranchia, there are over 20 families.

Below is a list of some of the more common families:

  • Aeolidiidae: This family is characterized by cerata that are often slender and arranged in rows.
  • Chromodorididae: This family is known for its brightly colored species, often with intricate patterns.
  • Dendronotidae: This family includes species with dendrite-shaped cerata.
  • Phyllidiidae: This family is characterized by its flattened bodies and leathery texture.

References

Wikipedia: Nudibranch
WoRMS: Nudibranchia
Discover Life: Nudibranchia