| Hemimycale columella | |
|---|---|
 | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Porifera |
| Class: | Demospongiae |
| Order: | Poecilosclerida |
| Family: | Hymedesmiidae |
| Genus: | Hemimycale |
| Species: | H. columella |
| Binomial name | |
| Hemimycale columella Bowerbank, 1874 | |
| Synonyms | |
| |
Hemimycale columella, the crater sponge, [1] is a species of marine demosponge in the family Hymedesmiidae. It is the type species of the genus Hemimycale and is widely distributed across the Atlanto-Mediterranean region.
Hemimycale columella is an encrusting sponge that grows in a cushion with a diameter of 10–30 cm and a thickness of more than 1 cm. It is usually pale orange or pink but can also be a brighter red color. Its surface is covered in shallow, circular pits of varying sizes, the rims of which are usually a lighter color than the rest of the organism. Inside the pits are pores which are covered by a fine mesh. [1] [2]
The unrelated species Phorbus fictitus and Hymedesmia pauperatus have characteristics similar to these. However, their color is slightly different, and the pits of P. fititus are more regular than those of H. columella. [1] [2]
Because of its complex morphology, the taxonomical placement of Hemimycale columella has changed often since its original description. James Scott Bowerbank first described the species as Desmacidon columella in 1874, taking particular note of its "exceedingly abundant" gemmules. [3] Émile Topsent then moved the species to Stylinos in 1891. He argued that the strongyles were sufficiently similar to warrant inclusion. However, in specimens from other localities from the ones he studied these similarities were not present. Thus, Desmacidon columella required its own genus. The situation was complicated further in the 1890s, as the composition and identity of Stylinos were brought into question. It was variously rejected entirely, synonymized with Stylotella , or retained as it was. At this point, the species was called Stylinos columella or Stylotella columella, but in 1932 the genus Prianos was resurrected by Max Walker de Laubenfels to house the newly segregated Prianos columella. This new name was not valid either, as the species had little in common with sponges previously placed in Prianos. [4]
Finally, in 1934, Maurice Burton proposed the novel name Hemimycale as the generic for Bowerbank's originally published Desmacidon columella, creating the new combination Hemimycale columella. The new construction referenced the similarities in larvae between the species and members of Mycale , as well as the clear differences between H. columella and all related sponges. However, even twenty years after the introduction of the new name, acceptance was not universal, with biologists in the 1950s still referring to the species as belonging to its previous genera. [4]
Some sponges have an affinity for convergent evolution when they occupy similar ecological niches, creating the possibility for cryptic species that are not closely related but are nearly morphologically identical. Often, the most effective way to find these cryptic species is to analyze the molecular phylogenetics of different populations of the same species which may be separated physically, behaviorally, or environmentally. Two distinct populations of Hemimycale columella exist which have been studied this way: one found in shallow water and one in deeper water. The results of these phylogenetic analyses suggested that H. columella as it is currently described may actually encompass two species. A 2017 paper argued that the shallow water Mediterranean populations actually represent a separate species: Hemimycale mediterranea . This new species has very few visible differences from H. columella, but does appear to lack styles entirely and is typically more brownish in color. [5]
The species is found attached to bedrock and boulders in silt-free littoral areas around the British Isles and in the Mediterranean Sea. [1] [2]
Sea urchins are the main predators of Hemimycale columella. There are numerous defensive mechanisms that H. columella used to avoid or discourage this predation. The two primary methods are secondary metabolites (organic compounds which are excreted) and calcibacteria (endosymbiotes which form a shield-like structure). While sea urchin species like Paracentrotus lividus regularly consume sponges with only calcibacterial defenses, it has not been observed to prey upon H. columella due to the combination of chemicals and calcibacteria. The presence of the calcibacteria in the flesh of the sponge also decreases its nutritional content, possibly causing some herbivorous fishes to choose other prey. [6]
Hemimycale columella is hermaphroditic and gives birth to live offspring. The development of new generations typically begins with the increase in water temperature over the summer, with embryo development lasting from around September to October. These embryos develop at different rates over this period, and varying stages of embryos can be found in a single parent organism. Once they develop into larvae, the young are dispersed with the rapid decrease in water temperature in late October. [7]
Sea urchins are spiny, globular echinoderms in the class Echinoidea. About 950 species of sea urchin are distributed on the seabeds of every ocean and inhabit every depth zone from the intertidal seashore down to 5,000 meters. The spherical, hard shells (tests) of sea urchins are round and covered in spines. Most urchin spines range in length from 3 to 10 cm, with outliers such as the black sea urchin possessing spines as long as 30 cm (12 in). Sea urchins move slowly, crawling with tube feet, and also propel themselves with their spines. Although algae are the primary diet, sea urchins also eat slow-moving (sessile) animals. Predators that eat sea urchins include a wide variety of fish, starfish, crabs, marine mammals, and humans.
Nudibranchs are 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.
Clingfishes are fishes of the family Gobiesocidae, the only family in the order Gobiesociformes. These fairly small to very small fishes are widespread in tropical and temperate regions, mostly near the coast, but a few species in deeper seas or fresh water. Most species shelter in shallow reefs or seagrass beds, clinging to rocks, algae and seagrass leaves with their sucking disc, a structure on their chest.
A spongivore is an animal anatomically and physiologically adapted to eating animals of the phylum Porifera, commonly called sea sponges, for the main component of its diet. As a result of their diet, spongivore animals like the hawksbill turtle have developed sharp, narrow bird-like beak that allows them to reach within crevices on the reef to obtain sponges.
Polymastia is a genus of sea sponges containing about 30 species. These are small to large encrusting or dome-shaped sponges with a smooth surface having many teat-shaped projections (papillae). In areas of strong wave action, this genus does not grow the teat structures, but instead grows in a corrugated form.
Ircinia strobilina is a species of sponge in the family Irciniidae. It is grey or shiny black in colour, with spiny structures (conules) dotting the surface. The spiny structures are interconnected by ridges, though not arranged in an orderly lattice. This species is globular and massive in shape, but usually no more than 0.3 metres (1 ft) across. I. strobilina is lobed and spherical and has a tough consistency. The large excurrent pores are located in depressions at the top of the sponge. Many smaller incurrent pores are scattered across the surface, more densely at the sides.
Chemical defense is a strategy employed by many organisms to avoid consumption by producing toxic or repellent metabolites or chemical warnings which incite defensive behavioral changes. The production of defensive chemicals occurs in plants, fungi, and bacteria, as well as invertebrate and vertebrate animals. The class of chemicals produced by organisms that are considered defensive may be considered in a strict sense to only apply to those aiding an organism in escaping herbivory or predation. However, the distinction between types of chemical interaction is subjective and defensive chemicals may also be considered to protect against reduced fitness by pests, parasites, and competitors. Repellent rather than toxic metabolites are allomones, a sub category signaling metabolites known as semiochemicals. Many chemicals used for defensive purposes are secondary metabolites derived from primary metabolites which serve a physiological purpose in the organism. Secondary metabolites produced by plants are consumed and sequestered by a variety of arthropods and, in turn, toxins found in some amphibians, snakes, and even birds can be traced back to arthropod prey. There are a variety of special cases for considering mammalian antipredatory adaptations as chemical defenses as well.
Callyspongia (Cladochalina) aculeata, commonly known as the branching vase sponge is a species of sea sponge in the family Callyspongiidae. Poriferans are typically characterized by ostia, pores that filter out plankton, with an osculum as the opening which water leaves through, and choanocytes trap food particles.
Paracentrotus lividus is a species of sea urchin in the family Parechinidae commonly known as the purple sea urchin. It is the type species of the genus and occurs in the Mediterranean Sea and eastern Atlantic Ocean.
Sterechinus neumayeri, the Antarctic sea urchin, is a species of sea urchin in the family Echinidae. It is found living on the seabed in the waters around Antarctica. It has been used as a model organism in the fields of reproductive biology, embryology, ecology, physiology and toxicology.
Geitodoris planata is a species of sea slug or dorid nudibranch, a marine gastropod mollusk in the family Discodorididae.
Cidaris cidaris is a species of sea urchin commonly known as the long-spine slate pen sea urchin. It is found in deep water in the eastern Atlantic Ocean and the Mediterranean Sea.
Cliona viridis, commonly called the green boring sponge, is a species of demosponge in the family Clionaidae. Its form varies according to the nature of the surface on which it grows. In limestone and other calcareous substrates it excavates channels and chambers while on other types of rock it encrusts the surface or forms massive structures. It is native to the eastern Atlantic, the Mediterranean Sea and the Indo-Pacific Ocean.
Argyrotheca is a genus of very small to minute lampshells. All species share a large pedicel opening, one ridge on the inside of the pedunculate valve, pits in a diamond pattern on the inside of both valves, and without radial ridges that end in tubercles. It occurs in depths between 6 and 1300 m. It is known since the latest Cretaceous.
Hippospongia communis also known as the honeycomb bath sponge, is a marine sponge in the phylum Porifera.
Biemna variantia is a species of sponge in the family Biemnidae. It is native to the northwestern Atlantic Ocean, the northeastern Atlantic Ocean, the North Sea and the Mediterranean Sea. This species was first described in 1858 by the British naturalist James Scott Bowerbank, who gave it the name Halichondria variantia. It was later moved to the genus Biemna and is the type species of the genus. The type locality is Tenby, Wales.
Hymeniacidon kitchingi is a species of sponge in the class Demospongiae. It is found in shallow waters in the northeastern Atlantic Ocean. This species was first described in 1935 by the British zoologist Maurice Burton. He placed it in a new genus because of its unusual spicules, and named it Rhaphidostyla kitchingi, in honour of Dr J. A. Kitching, who had collected the original specimen. It was later transferred to the genus Hymeniacidon.
Dysidea etheria, commonly known as the ethereal sponge or heavenly sponge, is a species of lobate sponge within the class Demospongiae. This marine sponge is known for its light blue color and can be found in the Caribbean as well as off the coasts of Florida and Georgia. Like all other poriferans, D. etheria is capable of both sexual and asexual reproduction. The use of spicule collection as well as chemical defenses allows D. etheria to protect itself against predators such as the zebra doris and the orange knobby star. D. etheria is also known as a host species of the invasive brittle star Ophiothela mirabilis. Lastly, various molecular biology studies have utilized D. etheria to both study foreign particle transport in sponges and to isolate novel molecules.
María Jesús (Iosune) Uriz Lespe is a pioneer in taxonomy, biology and population genetics of marine sponges, with a wide international recognition. In recent years she has focused her research on evolutionary and functional aspects of the symbiotic relationships between sponges and microorganisms, interacting with the renowned American specialist Lynn Margulis. Her line of research in the biological activities of sponge secondary metabolites gave rise to a continued collaboration with pharmaceutical companies that have allowed the development of antitumor drugs.
Hamacantha is a genus of sponges in the family Hamacanthidae. This species in this genus differ from those in the other genera in this family through the presence of diancistras, distinctive microscleres. These are thought to aid in framing the skeleton by joining monactine megascleres. This genus contains 30 species in three subgenera.