Phestilla minor

Last updated

Phestilla minor
Phestilla minor (couple avec ponte).jpg
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Mollusca
Class: Gastropoda
Order: Nudibranchia
Suborder: Cladobranchia
Superfamily: Fionoidea
Family: Trinchesiidae
Genus: Phestilla
Species:
P. minor
Binomial name
Phestilla minor
Rudman, 1981 [1]

Phestilla minor is a species of sea slug in the Trichechidae family. It is a type of aeolid nudibranch (Latin for naked gills) under the Aeolidina suborder. Phestilla minor is a benthic sea slug that is a very small, slow-moving organism found in marine habitats all over the world.

Contents

Phestilla minor is one of over 2000 species of sea slugs.

Description

Phestilla minor is a small marine invertebrate that can grow to reach a maximum length of approximately 7mm.

Physical characteristics

The body is separated into three sections: the foot, head and visceral mass. Its foot has a flattened sole-like make-up that is used for moving over substrates. Phestilla minor has a swollen distal tip and one swollen collar region below the tip.

This species is coloured to blend in with its surroundings, only found to be in one colour form, with very minimal pigmentation which allows it to camouflage into its environment, particularly the colour of the coral colony. This acts as a defence mechanism from potential prey which can include fish, lobster, crabs and also humans. Its other form is a very deeply pigmented opaque bleach colour which blends in with the shape and colour of tiny abrasions, scars formed by feeding fish, that are scattered all over reef corals known as porites colonies.

Ecology

Distribution

Phestilla minor has a wide Indo-west pacific distribution. It is a marine species found commonly in marine habitats such as reefs, intertidal areas, and deep oceans particularly in warm, tropical areas. This species has been recorded from East Africa (Tanzania), Australia (Great Barrier Reef) and Hawaii. [2] In Australia, the Phestilla Minor has been recorded along the east coast from northern Queensland down to northern New South Wales. [3]

Habitat

Phestilla mMinor is found only in marine habitats, at the bottom of the ocean. Known to have very sedentary lives this species spends most of its life attached to one organism which is usually coral reef. Phestilla minor is found to always be associated with colonies of Porites , a stony coral on which it feeds. [4]

Diet

Phestilla minor sea slug feeds on the hard-coral genus Porites , the same one on which it lives. It has a pair of jaw and a radula (tongue-like organism) that consist of multiple rows of very small teeth which they use to feed e.g. on plankton, algae and jellyfish. The radula is used to gather food particles through scraping or tearing of other organisms. Whilst feeding, Phestilla minor uses many defensive behaviours to protect or harm potential predators. The sea slugs cover their food with particles of mucus as a defence mechanism to protect their food from potential prey. Luckily, there are very few organisms that will prey on Phestilla minor. Organisms such as spines, exoskeletons, and stinging cells are the only known forms of prey to this sea slug.

Reproduction

When mating, Phestilla minor uses a powerful mix of chemicals to attract a mating partner. As the organism is majorly blind, it uses these chemicals as a sexual attractant known as a pheromone to help the organisms find each other. [5] These protein pheromones are used by the species in order to attract a potential mating partner. It is a chemical that the slug uses to change the behaviour of another animal, a ‘behaviour-altering’ agent. This process of using a pheromone message has also been found in many other marine animals e.g. fish and dolphins, and research from Phestilla minor can be synthesised to develop greater research for other marine life.

Phestilla minor spends majority of its life in isolation and attached to one organism, however, during warmer summer seasons, the species gather in masses. Gatherings consist of hundreds of individual sea slugs that all gather with the intention of breeding. This occasion of mass gathering of the sea slugs can last anywhere between an hour to a few days.

During this process of gathering, eggs from the slugs are laid in large masses which can vary anywhere between one hundred to millions of individual eggs waiting to be fertilized. Phestilla minor will normally form a pair with another sea slug in which they lay their eggs. When laying their eggs, they will normally produce approximately 10 separate egg masses, each egg mass consistent of approximately 120 individual eggs. The eggs are usually laid in conjunction with the coral colonies on which the organism attaches itself to. The eggs grow at a very rapid speed, starting from a size of 2mm, growing to a mature size of approximately 9mm wide which usually takes about 10 days in total. As the larvae are lecithotrophic, they are competent to metamorphose almost immediately after hatching, which is usually 5–6 days post-fertilization. [6] The eggs laid by the Phestilla minor can be either curved or straight and be in the form of a semicircle shape.

The fertilization process may not take place instantly, but whilst waiting for the eggs to reach their full maturity, the sperm can be stored within an organ called the seminal receptacle. When the eggs finally do hatch, a larva called veliger (free-swimming creatures that have a clear, thin shell) emerges to create a hard shell around them to protect itself, a process that takes around seven days in total.

Phestilla minor is a hermaphrodite, meaning that each individual organism consists of both male and female sexual organs which allows it to produce both eggs and sperm simultaneously. [7] The Phestilla minor’s flexibility in sexual roles and allocation is unique to all hermaphrodites. Other examples of hermaphrodites are worms, bryozoans, trematodes, snails and barnacles. Within an individual slug, the reproductive systems keep these organisms and systems completely separate. [8] Through possessing two different sexes it means that between mating partners there can be serious conflicts of interests which can consequently lead to conflicting compatibility interests. This is because both may choose to mate in the role of either the male or the female.

Threats

When sea slugs hatch or break out of their eggs, it is common for only a few eggs to survive. Due to the large masses of eggs hatching, they are at high risk from predators eating them. However, the large number of eggs increases the chances of some eggs surviving to adulthood, where they are then able to fend for themselves using protective strategies and be able to reproduce in the future.

Because Phestilla minor is such a small organism, this animal is at such high risk and is vulnerable to an array of other sea creatures. Predators of Phestilla minor include fish, crabs, lobsters and many other animals. Humans are another predator of the Phestilla minor, being caught for aquarium purposes, to be sold on the exotic pet markets and as part of a dish.

Another threat that the sea slug faces, is from each other. Sea slugs are known to be cannibals, eating each other when food supplies are low, either dead or alive. Typically, it is the larger slugs that feed on the smaller slugs.

Life span

Most sea slug species will live for approximately one year, with some species living for less than one year. Phestilla minor is known to have a lifespan of about one year. It becomes sexually mature in about 38 days.

Human relations

Conservation status

Sea slugs are not listed as a threatened or endangered species. No species of this marine animal are listed by the International Union for Conservation of Nature. [9] Sea slugs are not currently listed on the endangered species list, however, it is their habitat that is vulnerable. Environments such as coral reefs are under threat by things such as pollution, habitat destruction and habitat loss.

Further research

Whilst sea slugs, and particularly Phestilla minor are such a tiny organism, they hold large significance in the field of scientific research. Sea slugs are extremely helpful to people and particularly scientists. The research is significant in laboratory studies of neuroethology, which is the study of how the brain controls behaviour. The slugs provide the basis of many testing grounds for a lot of theories and investigation into how the nervous system works. Through observation and analysis of the sea slug’s natural behaviours and sensory cues that trigger these, scientists gain new research material by studying them under experimental conditions to be used in laboratories. Study is conducted into the mating rituals, feeding, reproductive cycles of the slugs which guides scientists to finding linkages between sea slugs and other animals.

Related Research Articles

<span class="mw-page-title-main">Nudibranch</span> Order of gastropods

Nudibranchs belong to the order Nudibranchia, a group of soft-bodied marine gastropod molluscs that shed their shells after their larval stage. They are noted for their often extraordinary colours and striking forms, and they have been given colourful nicknames to match, such as "clown", "marigold", "splendid", "dancer", "dragon", and "sea rabbit". Currently, about 3,000 valid species of nudibranchs are known.

<span class="mw-page-title-main">Spanish dancer</span> Species of gastropod

The Spanish dancer, scientific name Hexabranchus sanguineus, is a dorid nudibranch, a very large and colorful sea slug, a marine gastropod mollusk in the family Hexabranchidae.The taxonomy of the genus Hexabranchus has been controversial but a thorough molecular and morphological study published in 2023 showed that the name H. sanguineus was being used for at least 5 distinct species.

External fertilization is a mode of reproduction in which a male organism's sperm fertilizes a female organism's egg outside of the female's body. It is contrasted with internal fertilization, in which sperm are introduced via insemination and then combine with an egg inside the body of a female organism.

<i>Glaucus atlanticus</i> Species of mollusc

Glaucus atlanticus is a species of sea slug in the family Glaucidae.

<span class="mw-page-title-main">Penis fencing</span> Mating ritual in hermaphroditic flatworms

Penis fencing is a mating behavior engaged in by many species of flatworm, such as Pseudobiceros hancockanus. Species which engage in the practice are hermaphroditic; each individual has both egg-producing ovaries and sperm-producing testes.

<i>Spirobranchus giganteus</i> Species of marine tube worm

Spirobranchus giganteus, commonly known as the Christmas tree worm, is a tube-building polychaete worm belonging to the family Serpulidae. The S. giganteus lives in coral reefs in the Indo-Pacific region to the Caribbean.

<i>Chromodoris annae</i> Species of gastropod

Chromodoris annae also known as the Anna's magnificent sea slug is a species of sea slug, a very colourful nudibranch, a shell-less marine gastropod mollusc in the family Chromodorididae.

<i>Aplysia vaccaria</i> Species of gastropod

Aplysia vaccaria, also known as the black sea hare and California black sea hare, is a species of extremely large sea slug, a marine, opisthobranch, gastropod mollusk in the family Aplysiidae. It is the largest sea slug species.

<i>Chromodoris orientalis</i> Species of gastropod

Chromodoris orientalis is a species of colourful sea slug, a dorid nudibranch, a marine gastropod mollusc in the family Chromodorididae. Sea slugs are generally very beautifully colored organisms with intense patterns and ranging in sizes. The Chromodoris orientalis specifically is a white sea slug with black spots in no particular pattern with a yellow, orange, or brown in color ring around its whole body and on its gills. There is much discussion on where it is found, what it eats, how it defends itself without a shell, and its reproduction methods. This is all sought after information because there is not much known about these animals.

<i>Phestilla melanobrachia</i> Species of gastropod

Phestilla melanobrachia is a species of sea slug, an aeolid nudibranch, a marine gastropod mollusk in the family Trinchesiidae.

<i>Drupella cornus</i> Species of gastropod

Drupella cornus, common name : the horn drupe, is a species of sea snail, a marine gastropod mollusk in the family Muricidae, the murex snails or rock snails.

<i>Chelidonura sandrana</i> Species of gastropod

Chelidonura sandrana is a species of sea slug, or "headshield slug", a marine opisthobranch gastropod mollusk in the family Aglajidae.

<span class="mw-page-title-main">Corallivore</span> Animal that feeds on coral

A corallivore is an animal that feeds on coral. Corallivores are an important group of reef organism because they can influence coral abundance, distribution, and community structure. Corallivores feed on coral using a variety of unique adaptations and strategies. Known corallivores include certain mollusks, annelids, fish, crustaceans, flatworms and echinoderms. The first recorded evidence of corallivory was presented by Charles Darwin in 1842 during his voyage on HMS Beagle in which he found coral in the stomach of two Scarus parrotfish.

<i>Phestilla lugubris</i> Species of gastropod

Phestilla lugubris is a species of sea slug, an aeolid nudibranch, a marine gastropod mollusk in the family Trinchesiidae.

<i>Phestilla sibogae</i> Species of gastropod

Phestilla sibogae is a species of sea slug, an aeolid nudibranch, a marine gastropod mollusk in the family Trinchesiidae. The species feeds on the hard coral genus Porites.

Phestilla panamica is a species of sea slug, an aeolid nudibranch, a marine gastropod mollusk in the family Trinchesiidae. The species feeds on the hard coral genus Porites.

Phestilla poritophages is a species of sea slug, an aeolid nudibranch, a marine gastropod mollusk in the family Trinchesiidae. The species was named after its prey genus, the hard coral Porites.

<i>Phyllodesmium poindimiei</i> Species of gastropod

Phyllodesmium poindimiei is an Alcyonacea feeding, aeolid nudibranch Gastropod belonging to the family Facelinidae. Cerata are important in this clade in terms of their physical defense and efficient metabolic processes. This species is spread sporadically along tropical coastal regions such as Australia, Hawaii, and the Indo-Pacific living in diverse marine habitats such as coral reefs. Unlike other species in the Opisthobranch Mollusca clade, P. poindimiei’s lush pink cerata are used for defensive purposes other than Nematocyst (dinoflagellate) capture and toxin release. Organismal ties within these thriving, tropical ecosystems can be determinants of environment change, which affects massive coral ecosystems. Continuously changing marine ecosystems, such as coral reefs, are directly linked to the evolution of organisms that live and thrive in the tropics such as the soft nudibrach P. poindimiei.

<i>Berthellina citrina</i> Species of sea slug

Berthellina citrina, the orange gumdrop, is a species of sea slug in the family Pleurobranchidae. It is found in rock pools in the intertidal zone and in shallow water in the tropical and subtropical Indo-Pacific region.

<i>Phestilla viei</i> Coral-feeding sea slug

Phestilla viei is a species of coral-feeding sea slug, an aeolid nudibranch, from the family Trinchesiidae, described in 2020. It has been identified as a sister species of Phestilla fuscostriata based on DNA barcoding using the COI gene. The genus Phestilla currently includes nine recognized species, eight of which are obligate corallivores, with each particular species predating on only one species or genus of coral. Its distribution is restricted to the Indo-Pacific Ocean.

References

  1. ↑ Rudman, W. B. (1981). Further studies on the anatomy and ecology of opisthobranch molluscs feeding on the scleractinian coral Porites. Zoological Journal of the Linnean Society. 71: 373-412.
  2. ↑ Rudman, W. B. (15 July 2010). "Phestilla minor". Australian Museum Sea Slug Forum.
  3. ↑ Nimbs, M.; Smith, A. D. (2018). "Beyond Capricornia: Tropical Sea Slugs (Gastropoda, Heterobranchia) extend their distribution into the Tasman Sea". Diversity. 10 (3): 99. doi: 10.3390/d10030099 .
  4. ↑ Rudman, W.B. (15 July 2010). "Phestilla Minor". Australian Museum Sea Slug Forum.
  5. ↑ "How sea slugs fall in love". Fresh Science.
  6. ↑ Ritson-Williams, R; Shjegstad, S; Paul, V (2003). "Host specificity of four corallivorous Phestilla nudibranchs (Gastropoda: Opisthobrancha)". Marine Ecology Progress Series. 255 (207–218): 5–7. Bibcode:2003MEPS..255..207R. doi: 10.3354/meps255207 .
  7. ↑ Mills, K. "Opisthobranchia (Sea Slugs), Grizmek's Animal Life Encyclopedia".
  8. ↑ Anthes, N; SChmitt, V; Michiels, N. "Mating behavior in the sea slug Elysia timida (Opisthobranchia, Sacoglossa): hypodermic injection, sperm transfer and balanced reciprocity". Frontiers in Zoology. 4 (17).
  9. ↑ "The ICUN red list of threatened species". ICUN.

Reference list

This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.