Overview

Brief Summary

Nudibranchs, meaning “naked gills” consist of soft-bodied sea slugs and are members of the class Gastropoda in the phylum Mollusca. The majority of the colorful opisthobranchs that are seen belong to the suborder Nudibranchia. Nudibranchs can be found anywhere from the depths of the ocean, to tidal pools, to coral reefs, but are most diverse in tropical waters.Nudibranchs have an irregular shape that can be thick or flattened and long or short and can range anywhere from 0.635 centimeters to 60.96 centimeters. The average lifespan of a nudibranch can vary anywhere from weeks to one year, based on the abundance of food available to them. Nudibranchs are carnivores and use their radula, a band of curved teeth, to scrape or tear food particles. They feed on species such as hydroids, sea anemones, corals, sponges and fish eggs. Each species of nudibranch usually specializes on one specific sessile animal on which to feed. Nudibranchs move or “crawl” by ciliary action or the muscular action of its foot, a flat and broad muscle that clings to rocks, corals, sponges and other surfaces.

Although separated into four different groups, the two most common groups of nudibranchs are the aeolidida (aeolids) and the doridoidea (dorids). Doridoidea is the largest group of nudibranchs and is comprised of many different variations of body types. Aeolidida are the second largest subgroup of nudibranchs and show a more consistent elongated shape. Nudibranchs have both male and female sex organs, making them hermaphrodites. Although hermaphroditic, self-fertilization does not occur. Only when the reproductive pores of two nudibranchs line up, neck to neck, can fertilization ensue.

Nudibranchs have obtained different defenses in order to escape predation; chemical defenses are obtained from their prey by ingestion, and are then incorporated into nudibranch tissues. The bright colors and patterns of nudibranchs serve as a warning signal to predators of their chemical defenses. Alternatively, the coloration of nudibranchs could also be a camouflage mechanism, allowing them to blend in to various substrates.

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Ecology

Associations

Known prey organisms

  • Christian RR, Luczkovich JJ (1999) Organizing and understanding a winter’s seagrass foodweb network through effective trophic levels. Ecol Model 117:99–124
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© SPIRE project

Source: SPIRE

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Known predators

Nudibranchia (Predatory gastropods) is prey of:
Urophycis floridana
Prionotus scitulus
Prionotus tribulus
sediment POC

Based on studies in:
USA: Florida (Estuarine)

This list may not be complete but is based on published studies.
  • Christian RR, Luczkovich JJ (1999) Organizing and understanding a winter’s seagrass foodweb network through effective trophic levels. Ecol Model 117:99–124
Creative Commons Attribution 3.0 (CC BY 3.0)

© SPIRE project

Source: SPIRE

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Evolution and Systematics

Evolution

Classification

Nudipleura (clade; this is [Pleurobranchiomorpha + the nudibranchs]) is skipped because (1) we are already short of ranks at this level of the tree and (2) it is useful to keep such a well-known name as Nudibranchia at its traditional Order level, as long as it is tenable. The concept of Nudipleura is nevertheless correct and has been given strong support by Grande et al. (2004) against the traditional grouping Notaspidea = [Umbraculida + Pleurobranchiomorpha] permanently ruled out). Based on molecular data (Grande et al., 2004), the Nudibranchia were challenged to be a polyphyletic group, with Pleurobranchomorpha being the sister to the Anthobranchia. Conversely, Wägele & Willan (2000) found strong morphological evidence for the monophyly of Nudibranchia. Four years later, there does not seem to be any additional evidence that Nudibranchia are not monophyletic so they are retained as a valid taxon until convincingly challenged.
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© WoRMS for SMEBD

Source: World Register of Marine Species

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Functional Adaptations

Functional adaptation

Branches accommodate algae: sea slug
 

The gut of one sea slug accommodates the algae it farms for nutrition by branching into leaf-like tentacles for increased housing space.

   
  "One sea-slug common on the Great Barrier Reef in Australia has taken this practice even further. It is able to stimulate its captive algae so that they proliferate to an unusual degree. To accommodate the greater numbers produced in this way, it develops branches in its gut which extend into leaf-like tentacles along its flanks. Having stocked its tentacles with plants, the sea-slug moves away from the feeding grounds among the coral where it first acquired the algae. It seldom if ever feeds on coral again. It is sustained entirely, it seems, by its internal gardens." (Attenborough 1995:204-205)
  Learn more about this functional adaptation.
  • Attenborough, D. 1995. The Private Life of Plants: A Natural History of Plant Behavior. London: BBC Books. 320 p.
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© The Biomimicry Institute

Source: AskNature

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Molecular Biology and Genetics

Molecular Biology

Statistics of barcoding coverage

Barcode of Life Data Systems (BOLD) Stats
                                        
Specimen Records:1,307Public Records:1,079
Specimens with Sequences:1,118Public Species:191
Specimens with Barcodes:1,096Public BINs:400
Species:260         
Species With Barcodes:244         
          
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© Barcode of Life Data Systems

Source: Barcode of Life Data Systems (BOLD)

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Barcode data

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© Barcode of Life Data Systems

Source: Barcode of Life Data Systems (BOLD)

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Locations of barcode samples

Collection Sites: world map showing specimen collection locations for Nudibranchia

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© Barcode of Life Data Systems

Source: Barcode of Life Data Systems (BOLD)

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Genomic DNA is available from 16 specimens with morphological vouchers housed at Museum of Tropical Queensland and Queensland Museum
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© Ocean Genome Legacy

Source: Ocean Genome Resource

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