| Megabalanus stultus | |
|---|---|
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Thecostraca |
| Subclass: | Cirripedia |
| Order: | Balanomorpha |
| Family: | Balanidae |
| Genus: | Megabalanus |
| Species: | M. stultus |
| Binomial name | |
| Megabalanus stultus (Darwin, 1854) | |
| Synonyms | |
Balanus stultusDarwin, 1854 | |
Megabalanus stultus is a species of barnacle first described by Charles Darwin in 1854. It lives on fire corals of the genus Millepora in the Atlantic Ocean from Florida to southern Brazil.
Megabalanus stultus is one of three species of barnacle that live on fire corals (the genus Millepora). Savignium milleporae lives in the Indo-Pacific and lives on 9 species of Millepora; Megabalanus ajax lives in the western Pacific and lives on Millepora platyphylla ; Me. stultus lives in the western Atlantic, and lives on Mi. alcicornis and Mi. complanata . [1] The nature of the relationship between M. stultus and the coral is unclear. At low densities, the barnacle has no discernible effect on the coral, but high-densities of coral-inhabiting barnacles can disrupt the growth of the colony. [1]
In his original description of the species, Darwin reported that M. stultus occurred in Singapore and the West Indies. In 1968, Arnold Ross considered the reports of M stultus from the Pacific Ocean to be erroneous, [2] limiting the type locality to the West Indies. M. stultus has subsequently been reported from Taiwan in the western Pacific, [3] and those records have been reassessed as referring to the related species Megabalanus ajax . [4]
M. stultus is now thought to occur exclusively in the western Atlantic, including the Caribbean Sea, from Florida to Rio de Janeiro, Brazil. [5]
Megabalnus stultus differs from the other species of Megabalanus in that the basal margin is sinuous, rather than straight, and protrudes medially, whereas in other species it protrudes little if at all. [5] The shell is "dirty white" in colour, often with a purple tinge, and pale blue in parts. [5]
Megabalanus stultus was first described by Charles Darwin in 1854, under the name Balanus stultus. It was placed in the subgenus Megabalanus by Ross in 1968, [2] which was raised to the rank of genus in 1976. [4] [6]
Barnacles are a type of arthropod constituting the subclass Cirripedia in the subphylum Crustacea, and are hence related to crabs and lobsters. Barnacles are exclusively marine, and tend to live in shallow and tidal waters, typically in erosive settings. Around 1,000 barnacle species are currently known.
Fire corals (Millepora) are a genus of colonial marine organisms that exhibit physical characteristics similar to that of coral. The name coral is somewhat misleading, as fire corals are not true corals but are instead more closely related to Hydra and other hydrozoans, making them hydrocorals. They make up the only genus in the monotypic family Milleporidae.
Acorn barnacle and acorn shell are vernacular names for certain types of stalkless barnacles, generally excluding stalked or gooseneck barnacles. As adults they are typically cone-shaped, symmetrical, and attached to rocks or other fixed objects in the ocean. Members of the barnacle order Balanomorpha are often called acorn barnacles.
The Balanomorpha are an order of barnacles, containing familiar acorn barnacles of the seashore. The order contains these families:
Megabalanus is a genus of barnacles in the family Balanidae. Members of the genus grow to 7 cm (2.8 in) in length and inhabit the lower intertidal zone.
Chthamalus is a genus of barnacles that is found along almost all non-boreal coasts of the northern hemisphere, as well as many regions in the southern hemisphere. These small barnacles have been studied in part because of the taxonomic confusion over a group of species that, by and large, are morphologically and ecologically quite similar. In recent years, molecular techniques have identified a number of cryptic species that have been subsequently confirmed by taxonomists using morphological measurements. Most recently the genus has been shown to be paraphyletic, with the genus Microeuraphia nested within Chthamalus.
Balanus nubilus, commonly called the giant acorn barnacle, is the world's largest barnacle, reaching a diameter of 15 cm (6 in) and a height of up to 30 cm (12 in), and containing the largest known muscle fibres.
Amphibalanus improvisus, the bay barnacle, European acorn barnacle, is a species of acorn barnacle in the family Balanidae.
Balanus crenatus is a species of acorn barnacle in the Balanidae family. It is found in the North Pacific and the North Atlantic Ocean.
Notochthamalus scabrosus, the only species in the genus Notochthamalus, is a species of barnacle found along the south-western and south-eastern coasts of South America, from Peru to the Falkland Islands. The species is found almost exclusively higher in the intertidal zone than the mussel Perumytilus, often codistributed with the confamilial barnacle Jehlius cirratus and Balanus flosculus.
Megabalanus tintinnabulum is a species of large barnacle in the family Balanidae. It is the type species of the genus. The specific name comes from the Latin tintinnabulum meaning a handbell and probably refers to the fact that small groups of barnacles resemble clusters of miniature bells.
Balanus trigonus is a species of barnacle in the family Balanidae. It is steep-sided, conical barnacle, has six shell plates and is pink in colour. They are opportunistic fouling organisms that are endemic to the Indo-Pacific region.
Milleporasquarrosa is a species of fire coral that can be found in the Caribbean Sea as well as in the western Atlantic. They are very common on fringing reefs in patches. They have a smooth surface covered in tiny pores from which polyps protrude. They can reach up to 5 centimeters in height and can range from brown or tan in color with slight purple or red tints. It is commonly known as "box fire coral", which refers to its box-like structure and the stinging sensation felt when touched with a bare hand. These corals are important to reef-building.
Megabalanus coccopoma, the titan acorn barnacle, is a tropical species of barnacle first described by Charles Darwin in 1854. Its native range is the Pacific coasts of South and Central America but it is extending its range to other parts of the world.
The Chthamaloidea are a subdivision of Balanomorpha proposed by Newman and Ross to include barnacles with shell wall composed of rostrum, carina, and one to three pairs of latera, rarely supplemented with one or more whorls of basal imbricating plates. The rostrolatus enters the sheath, but rarely fuses with the rostrum, as in the three higher superfamilies. Shell plates are simple in construction, solid, and incorporate organic chitin between carbonate layers. Opercular plates are deeply interlocked, and in some genera, may become concrescent with age. Soft part morphology includes concave labrum without notch in the central part. Cirrus III more resembles Cirrus IV than II, or may be intermediate in structure. Caudal appendages present in some species.
Catomerus is a monotypic genus of intertidal/shallow water acorn barnacle that is found in warm temperate waters of Australia. The genus and species is very easily identified by whorls of small plates surrounding the base of the primary shell wall; no other shoreline barnacle species in the Southern Hemisphere has that feature. This species is considered to be a relic, as these plates are found only in primitive living lineages of acorn barnacles or in older fossil species. The fact that this is an intertidal species is unusual, because living primitive relic species are often found in more isolated habitats such as deep ocean basins and abyssal hydrothermal vents.
Amphibalanus is a genus of barnacle of the family Balanidae that includes species formerly assigned to Balanus. It contains the following species:
The barnacle genus Nesochthamalus was erected by Foster & Newman, 1987, to include sole species Chthamalus intertextus originally named by Darwin in 1854. It is widespread on islands in Western Pacific Ocean, including Hawaii, and presents combinations of unusual features which make easily recognizable for field workers. These include dirty white shell exterior with deep purple colored interior, operculars colored purple. Opercular plates on each side calcify together in all but youngest individuals, and cannot be separated or easily distinguished from each other. This feature is shared only by Rehderella belyaevi, but in latter species, scutum and tergum can be distinguished by raised ridge replacing old articular margin. Unique feature of Nesochthamalus is its basis. In young individuals, it is entirely membraneous, and with age, becomes secondarily calcareous progressively inwards, leaving only the center membraneous. As the basis calcifies, it rises off the substrate forming a saucer shape when viewed from the side. In addition, interior of shell is secondarily calcified.
Millepora complanata, commonly known as blade fire coral, is a species of fire coral in the family Milleporidae. It is found in shallow waters in the Caribbean Sea where it is a common species. The International Union for Conservation of Nature has assessed its conservation status as being critically endangered.
