Amphiroa beauvoisii

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Amphiroa beauvoisii
Amphiroa zonata (in Amami).JPG
Scientific classification OOjs UI icon edit-ltr.svg
(unranked): Archaeplastida
Division: Rhodophyta
Class: Florideophyceae
Order: Corallinales
Family: Corallinaceae
Genus: Amphiroa
Species:
A. beauvoisii
Binomial name
Amphiroa beauvoisii
Synonyms

see text

Amphiroa beauvoisii is a species of thalloid red algae in the Corallinaceae family. It is widely distributed across the world, and can be found attached to rocks in intertidal areas. Individual organisms consist of a base of calcified material, tissue in the shape of branching fan-like planes growing out of it. It exhibits a wide range of morphologies based on where it is found, as well as different reproductive behaviors based on season and location.

Contents

Description

Portions of clumps of A. beauvoisii, under the synonym A. mexicana. Plate 47 (Taylor, 1945).jpg
Portions of clumps of A. beauvoisii, under the synonym A. mexicana.

Plants of Amphiroa beauvoisii grow on the surface of rocks, attached on their undersides by a calcified and crustose base. From this base, erect axes grow up to 85 mm (3.3 in) long. The axes are made up of alternating segments of calcified sections called intergenicula and non-calcified sections called genicula. [1] They branch out in a fan-like plane which is about 30 mm (1.2 in) tall, [2] usually split into two distinct branches, but rarely split into three or four. [1]

Morphology

The branches usually grow from the sections of intergenicula. These intergenicula are usually flat, but can be slightly more circular near the base. They are normally about the same width regardless of where they are on the organism, and measure 3–6.5 mm (0.12–0.26 in) long, 1–3.5 mm (0.039–0.138 in) wide, and 300–400 mm (12–16 in) thick. [3] However, they are sometimes wider towards their ends than at the base. [2] In the core of the organism, there are filaments which consist of one to four arched rows of larger cells which are 45–85 micrometers (μm) long. These rows alternate with a single row of shorter cells which is 6–40 μm long. In the periphery, these filaments are not arranged in rows. [4]

Fig. 1 shows a portion of the branches, without the base, of A. beauvoisii, under the synonym A. peninsularis. Plate 48 (Taylor, 1945).jpg
Fig. 1 shows a portion of the branches, without the base, of A. beauvoisii, under the synonym A. peninsularis.

The genicula typically are found where the branches split, or within 2 mm (0.079 in) of the split in the outward direction. [4] The filaments associated with the genicula remain calcified, even though the genicula themselves are not. This leads to these calcified filaments eventually cracking and falling off the organism, though they sometimes leave calcified spurs around the genicula. [1] Mature sections of genicula are made up of at least five rows of thick-walled cells. The transition from genicula to intergenicula occurs within these rows of cells, transitioning from one to the next between layers. [3]

The conceptacles, which contain the reproductive sporangia, are made up of a single pore. They are found scattered across the surface of the periphery of the intergenicula, protruding above the rest of the surface. [1] Each conceptacle is 220–330 μm wide and protrudes 85–140 μm above the surface. They are surrounded by a rick of block-like cells, which sometimes eventually shrink, leading to a moat-like depression around the raised conceptacle. [4] There are several types of sporangia found within the conceptacle. The tetrasporangia are formed around a central column of long sterile cells, and are found in conceptacles with more or less flat floors. They are found in groups of four per conceptacle, separated into their own zones. [1] The carposporangial conceptacles have a warty surface and are more oblong, and the carposporangia themselves have superficial gonimoblast filaments. [5]

Cellular characteristics

When viewed under a scanning electron microscope, the outlines of cells on the surface of the intergenicula are clear. They consist of calcified ridges 3–9 μm wide which split to form two narrower ridges at the middle lamella. There are concavities 5–14 μm wide on the surface layer of the thallus which are covered in cup-like formations that are calcified, lip-like openings. On the flanks of the apices of the branches there are ridges which surround the apices or make arched lines across the flat side of the compressed branches. These ridges sometimes take the form of simple bands or randomly organized raised cells, while in other places they are made up of complexly overlapping layers of cells. [6] They are harder to see the further away from the point of attachment they are, and on older intergenicula they disappear completely. [7]

Similar species

Amphiroa beauvoisii is very similar in appearance to several other species in the genus Amphiroa, including A. anceps, A. gracilis, and A. klochkovana . It can be differentiated from A. gracilis and A. klochkovana by its intergenicula, which are almost all compressed or flat, and its genicula, which do not include decalcified cells from the peripheral region. [8] It differs from A. anceps in its pore canals, in that the top of its canals are surrounded by a ring of large cells, while those of A. anceps are not. [9]

Taxonomy

Type specimen of A. beauvoisii at the Naturalis Biodiversity Center Naturalis Biodiversity Center - L.4028348 - Amphiroa beauvoisii J.V.Lamour. - Corallinaceae - Plant type specimen.jpeg
Type specimen of A. beauvoisii at the Naturalis Biodiversity Center

Jean Vincent Lamouroux provided the original description for Amphiroa beauvoisii in 1816, when he described it in his book Histoire des Polypiers Coralligènes Flexibles, Vulgairement Nommés Zoophytes. [10] He gave the specific epithet "beauvoisii" to honor Palisot de Beauvois, an 18th-century French entomologist and biologist. [1]

Holotype

Figs. 5 and 6 show specimens of A. beauvoisii from the type collection under the synonym A. drouetii. Plate 27 (Dawson, 1953).jpg
Figs. 5 and 6 show specimens of A. beauvoisii from the type collection under the synonym A. drouetii.

The holotype of the species was collected from a type locality called the "Côtes du Portugal" [11] (the coast of Portugal) by an unknown collector and was donated to the Lamouroux herbarium by de Beauvois, [12] where it remains as of 2013. [10] The holotype specimen consists of part of a single branched axis with calcified intergenicula and uncalcified genicula, as well as eight fragmentary parts of the same specimen, some of which have genicula. [13]

Synonymy

While Amphiroa beauvoisii does not have any homotypic synonyms, or officially invalid nomenclature, it does have several illegitimate names. Some of these are simply superfluous, while others are misapplied to A. beauvoisii. In 1824, Lamoroux introduced the named Amphiroa belvisii; however, he discussed A. beauvoisii as a synonym in his description, thus making A. belvisii an illegitimate and superfluous name. [1]

Several specimens of A. beauvoisii have been incorrectly described as representing other species of Amphiroa. At several times, it was misidentified as A. anceps, which were included in records of the species as recently as 1993. [1] William Henry Harvey reported A. beauvoisii as occurring in New South Wales, but these reports were based on misidentified specimens which were actually A. ephedraea. [12]

A list of heterotypic synonyms according to Adele Harvey et al. in 2009 is as follows: [14]

Later studies revealed A. exilis to be a distinct species from A. beauvoisii, with consistent characteristics being observed between the syntype and other Australian specimens of A. exilis. While its own species, A. exilis is still very closely related in appearance to A. beauvoisii. [15]

Distribution and habitat

Amphiroa beauvoisii is one of the most widely distributed species in the genus Amphiroa, found primarily in tropical and subtropical climates. It has been recorded from the Mediterranean, the Indian Ocean, the Gulf of California, the Caribbean, and the South African coast. [16] More recently, in 2009, it was found in temperate waters along the southwest, south, and southeast Australian coasts. [17] However, it is possible that some of the individuals collected from the southwest coast were actually misidentified A. anceps specimens. [18]

The habitat of the species is rocky intertidal pools, and it grows on the surface of rocks. It can be found at depths of up to 15 m (49 ft) below the surface of the water. [19]

Ecology

Life cycle

Red algae, including A. beauvoisii, exhibit different forms through different generations. This process typically begins as a gametophyte generation, then a sporophyte generation, then a carposporophyte generation which germinates into a tetrasporaphyte. [20] In A. beauvoisii, these different generations will exist in different proportions to one another depending on the geographic location. In subtropical climates, tetrasporangial, bisporangial and gametangial specimens have been found. There are three different proportions found in tropical regions: equal rates of gametangial and sporangial specimens (Pacific Mexico), mostly sporangial specimens (Gulf of California), or only tetrasporangial and bisporangial specimens (Caribbean). [21] In the Australian populations of A. beauvoisii, tetrasporangial forms are common, while gametangial and carposporangial forms have not been recorded. [4]

The size, cover, and frond length of A. beauvoisii varies seasonally. Additionally, the percentage of fronds that are in the tetrasporangial or bisporangial (reproductive) forms also changes based on the season, though this is not based solely on the seasonal temperature, but other factors as well. A population of A. beauvoisii will reproduce and persist both through germinating spores form these reproductive fronds as well as by re-growing the holdfast of the organism. [22]

Phytochemistry

Amphiroa beauvoisii has been tested for bioactive properties, but showed no activity in antibacterial, antifungal, antiviral, cytotoxic, or antimitotic applications. [23]

Related Research Articles

<span class="mw-page-title-main">Brown algae</span> Large group of multicellular algae, comprising the class Phaeophyceae

Brown algae, comprising the class Phaeophyceae, are a large group of multicellular algae, including many seaweeds located in colder waters within the Northern Hemisphere. Brown algae are the major seaweeds of the temperate and polar regions. They are dominant on rocky shores throughout cooler areas of the world. Most brown algae live in marine environments, where they play an important role both as food and as a potential habitat. For instance, Macrocystis, a kelp of the order Laminariales, may reach 60 m (200 ft) in length and forms prominent underwater kelp forests. Kelp forests like these contain a high level of biodiversity. Another example is Sargassum, which creates unique floating mats of seaweed in the tropical waters of the Sargasso Sea that serve as the habitats for many species. Many brown algae, such as members of the order Fucales, commonly grow along rocky seashores. Some members of the class, such as kelps, are used by humans as food.

<i>Fucus</i> Genus of brown algae

Fucus is a genus of brown algae found in the intertidal zones of rocky seashores almost throughout the world.

<span class="mw-page-title-main">Coralline algae</span> Order of algae (Corallinales)

Coralline algae are red algae in the order Corallinales. They are characterized by a thallus that is hard because of calcareous deposits contained within the cell walls. The colors of these algae are most typically pink, or some other shade of red, but some species can be purple, yellow, blue, white, or gray-green. Coralline algae play an important role in the ecology of coral reefs. Sea urchins, parrot fish, and limpets and chitons feed on coralline algae. In the temperate Mediterranean Sea, coralline algae are the main builders of a typical algal reef, the Coralligène ("coralligenous"). Many are typically encrusting and rock-like, found in marine waters all over the world. Only one species lives in freshwater. Unattached specimens may form relatively smooth compact balls to warty or fruticose thalli.

<i>Atractophora hypnoides</i> Species of alga

Atractophora hypnoides is a rare red alga (Rhodophyta) found in the British Isles, France and some Atlantic Islands and is the only species of the genus found in the British Isles. It is attached to the rock or other algae by a small basal disc and is much branched with downgrowing filaments which enclose the main branch or axis forming a cortex. Short filaments of limited growth radiate in whorls from the axis and frequently convert into hairs. The spreading filaments grow irregularly in a diffuse manner. Microscope examination is required for identification.

<i>Polysiphonia</i> Genus of algae

Polysiphonia is a genus of filamentous red algae with about 19 species on the coasts of the British Isles and about 200 species worldwide, including Crete in Greece, Antarctica and Greenland. Its members are known by a number of common names. It is in the order Ceramiales and family Rhodomelaceae.

<span class="mw-page-title-main">Conceptacle</span>

Conceptacles are specialized cavities of marine and freshwater algae that contain the reproductive organs. They are situated in the receptacle and open by a small ostiole. Conceptacles are present in Corallinaceae, and Hildenbrandiales, as well as the brown Fucales. In the Fucales there is no haploid phase in the reproductive cycle and therefore no alternation of generations. The thallus is a sporophyte. The diploid plants produce male (antheridia) and female (oogonia) gametangia by meiosis. The gametes are released into the surrounding water; after fusion, the zygote settles and begins growth.

<i>Calliarthron</i> Genus of red algae in the family Corallinaceae

Calliarthron is a genus containing two species of thalloid intertidal alga. Specimens can reach around 30 cm in size. The thalli take a crustose form. The organisms lack secondary pit connections. Calliarthron reproduces by means of conceptacles; it produces tetraspores, dispores and carpospores. The genus has lignin and contains secondary cell walls, traits which are normally associated with the vascular plants. It is similar to the genus Bossiella.

Bangia is an extant genus of division Rhodophyta that grows in marine or freshwater habitats. Bangia has small thalli with rapid growth and high reproductive output, and exhibits behavior characteristic of r-selected species. The plants are attached by down-growing rhizoids, usually in dense purple-black to rust-colored clumps. The chloroplasts of Bangia, like others in the division Rhodophyta, contain chlorophyll a and sometimes chlorophyll d, as well as accessory pigments such as phycobilin pigments and xanthophylls. Depending on the relative proportions of these pigments and the light conditions, the overall color of the plant can range from green to red to purple to grey; however, the red pigment, phycoerythrin, is usually dominant.

<i>Hildenbrandia</i> Genus of algae

Hildenbrandia is a genus of thalloid red alga comprising about 26 species. The slow-growing, non-mineralized thalli take a crustose form. Hildenbrandia reproduces by means of conceptacles and produces tetraspores.

The epithallium or epithallus is the outer layer of a crustose coralline alga, which in some species is periodically shed to prevent organisms from attaching to and overgrowing the alga.

<i>Amphiroa</i> Genus of algae

Amphiroa is a genus of thalloid red algae under the family Corallinaceae.

<i>Jania</i> (alga) Genus of algae

Jania is a genus of red macroalgae with hard, calcareous, branching skeletons in the family Corallinaceae.

<i>Spongites yendoi</i> Species of alga

Spongites yendoi is a species of crustose red seaweed with a hard, calcareous skeleton in the family Corallinaceae. It is found on the lower shore as part of a diverse community in the southeastern Atlantic Ocean and the Indo-Pacific Ocean.

<i>Polysiphonia lanosa</i> Species of alga

Polysiphonia lanosa is a common species of the red algae (Rhodophyta) often to be found growing on Ascophyllum nodosum.

<i>Notheia anomala</i> Species of seaweed

Notheia anomala is a macroalga in the family Notheiceae and the brown algae order Fucales. It is an obligate epiphyte of another brown algae, Hormosira banksii.

<i>Phycodrys rubens</i> Species of alga

Phycodrys rubens is a red marine alga of up to 30 cm long.

<i>Lithophyllum orbiculatum</i> Species of alga

Lithophyllum orbiculatum is a species of thalloid coralline algae, which are a red algae whose cell walls contain calcareous deposits.

<span class="mw-page-title-main">Callithamniaceae</span> Family of algae

Callithamniaceae is a family of red algae (Rhodophyta) in the order Ceramiales. The family was first described by Friedrich Traugott Kützing in 1843.

<i>Hildenbrandia rubra</i> Species of alga

Hildenbrandia rubra is a marine species of thalloid red alga. It forms thin reddish crusts on rocks and pebbles in the intertidal zone and the shallow subtidal zone. It is a common species with a cosmopolitan distribution, and is able to tolerate a wide range of conditions.

Crustaphytum is a genus of red alga first discovered in Taoyuan algal reefs by Taiwanese scientists. The epithet “crusta” refers to crustose thallus and “phytum” refers to plant. Belonging to the family Hapalidiaceae in the order Hapalidiales, Crustaphytum is one kind of crustose coralline algae.

References

Citations

  1. 1 2 3 4 5 6 7 8 Harvey et al. 2009, 267.
  2. 1 2 Economou-Amilli et al, 262.
  3. 1 2 Harvey et al. 2009, 267; Harvey et al. 2013, 87.
  4. 1 2 3 4 Harvey et al. 2013, 87.
  5. ↑ Riosmena-Rodriguez & Siqueiros-Beltrones, 138.
  6. ↑ Economou-Amilli et al, 263.
  7. ↑ Garbary & Johansen, 5.
  8. ↑ Harvey et al. 2009, 261.
  9. ↑ Harvey et al. 2009, 261. Harvey et al. 2013, 86.
  10. 1 2 Harvey et al. 2013, 86.
  11. ↑ Norris, 6.
  12. 1 2 Harvey et al. 2009, 268.
  13. ↑ Harvey et al. 2009, 270.
  14. ↑ Harvey et al. 2009, 269.
  15. ↑ Harvey et al. 2013, 99.
  16. ↑ Harvey et al. 2009, 273; Norris, 12.
  17. ↑ Harvey et al. 2009, 258.
  18. ↑ Harvey et al. 2009, 259.
  19. ↑ Harvey et al. 2009, 273.
  20. ↑ Lee.
  21. ↑ Rosas-Alquicira et al, 131.
  22. ↑ Rosas-Alquicira et al, 136.
  23. ↑ Ballesteros et al, 483.

Bibliography

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