| Waminoa brickneri | |
|---|---|
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Xenacoelomorpha |
| Order: | Acoela |
| Family: | Convolutidae |
| Genus: | Waminoa |
| Species: | W. brickneri |
| Binomial name | |
| Waminoa brickneri (Ogunlana, Hooge, Tekle, Benayahu, Barneah & Tyler, 2005) | |
Waminoa brickneri [1] [2] is a species of acoel from the coral reefs around the northern Red Sea [3] and the second described species in the genus (the first is Waminoa litus ).
Waminoa brickneri is discoid to obcordate in shape, flat, 3–4 mm in diameter and 1 mm thick. [3] Its bronze color with small white speckles is derived from the abundant dinoflagellate endosymbionts and the scattered white pigment spots. There are two distinct types of dinoflagellate endosymbionts that lay scattered throughout the parenchyma of the animal: small symbionts of the genus Symbiodinium [4] and larger symbionts of the genus Amphidinium . [5]
The epidermis is transparent, fully ciliated, and glandulous. The dorsal body wall and lateral sides are especially abundant with rhabdoid glands, while the ventral body wall is abundant with mucous glands; the mucous glands also occur scattered in the dorsal body wall, but there are no rhabdoid glands on the ventral side. [3]
The mouth is ventrally located, somewhere in the posterior third of the body length, and opens directly into the digestive syncytium. [3] Newly hatched juveniles possess a statocyst and paired eyes but mature individuals lack both. They also lack a frontal organ. The brain is bilobed and lies just beneath the epidermis close behind the anterior tip of the body; the two main masses consist of a central neuropile and nucleated rind and are connected by a short medial commissure. [3]
Like other acoelomorphs, Waminoa brickneri is a simultaneous hermaphrodite. [3] The reproductive organs produce a slightly thickened ridge medially in the terminal quarter of the body. A pair of ventrally situated ovaries extends from about the second quarter of the body length posteriorly behind the mouth. The female pore is prominent and opens to a ciliated vagina located on the ventral body wall immediately anterior to the male gonadopore. Dorsally and laterally to the ovaries lies a pair of testes, which lead posteriorly to the seminal vesicle. The seminal vesicle, which lies just in front of the posterior notch in the body margin, is most prominent, and appears white from contained sperm. It is well-developed and walled by thin, loosely concentric muscles and reaches to a penis papilla. Flanking the seminal vesicle are prominent false seminal vesicles continuous with the tracts of sperm descending from the testes. There is a seminal bursa with 2 or more (2–8) bursal nozzles. Sperm cells are elongated and biflagellate. [6]
Waminoa brickneri is an epizoic organism living on corals in the Gulf of Aqaba. [5] It occurs in groups of non-overlapping individuals, causing the corals it inhabits to appear spotted. It has been detected on 13 species of stony corals, and on one species of soft coral. It can be found at depths of 2 to 50 meters.
The presence of Waminoa species on live corals brought about several hypotheses about the nature of this coral-acoel association, one of which was that the acoels feed on the coral's mucus. A recent study by Naumann et al. (2010) corroborated this hypothesis. [7]
The seminal vesicles are a pair of convoluted tubular accessory glands that lie behind the urinary bladder of male mammals. They secrete fluid that largely composes the semen.
The ejaculatory ducts are paired structures in the male reproductive system. Each ejaculatory duct is formed by the union of the vas deferens with the duct of the seminal vesicle. They pass through the prostate, and open into the urethra above the seminal colliculus. During ejaculation, semen passes through the prostate gland, enters the urethra and exits the body via the urinary meatus.
The Turbellaria are one of the traditional sub-divisions of the phylum Platyhelminthes (flatworms), and include all the sub-groups that are not exclusively parasitic. There are about 4,500 species, which range from 1 mm (0.039 in) to large freshwater forms more than 500 mm (20 in) long or terrestrial species like Bipalium kewense which can reach 600 mm (24 in) in length. All the larger forms are flat with ribbon-like or leaf-like shapes, since their lack of respiratory and circulatory systems means that they have to rely on diffusion for internal transport of metabolites. However, many of the smaller forms are round in cross section. Most are predators, and all live in water or in moist terrestrial environments. Most forms reproduce sexually and with few exceptions all are simultaneous hermaphrodites.
Acoelomorpha is a subphylum of very simple and small soft-bodied animals with planula-like features which live in marine or brackish waters. They usually live between grains of sediment, swimming as plankton, or crawling on other organisms, such as algae and corals. With the exception of two acoel freshwater species, all known acoelomorphs are marine.
Xenoturbella is a genus of very simple bilaterians up to a few centimeters long. It contains a small number of marine benthic worm-like species.
Symsagittifera roscoffensis, also called the Roscoff worm, the mint-sauce worm, or the shilly-shally worm, is a marine acoel worm. The origin and nature of the green color of this worm stimulated the intrigued zoologists in the 1870's. It was discovered that the coloring resulted from the symbiosis between the animal and a green micro-algae, the species Tetraselmis convolutae, hosted under its epidermis. It is the photosynthetic activity of the micro-algae in hospite that provides the essential nutrients for the worm. This partnership is called photosymbiosis, from "photo", "light", and symbiosis "who lives with". These photosynthetic marine animals live in colonies on the tidal zone.
Convolutidae is a family of acoels, belonging to the phylum Xenacoelomorpha. This family contains more than a third of all known acoel species.
Acoela, or the acoels, is an order of small and simple invertebrates in the subphylum Acoelomorpha of phylum Xenacoelomorpha, a deep branching bilaterian group of animals, which resemble flatworms. Historically they were treated as an order of turbellarian flatworms. About 400 species are known, but probably many more not yet described.
Tomigerus clausus is a species of air-breathing land snail, a terrestrial pulmonate gastropod mollusk in the family Odontostomidae.
The reproductive system of gastropods varies greatly from one group to another within this very large and diverse taxonomic class of animals. Their reproductive strategies also vary greatly.
Pseudunela cornuta is a species of small sea slug, an acochlidian, a shell-less marine and temporarily brackish gastropod mollusk in the family Pseudunelidae. Adults are about 3 mm long and live in the spaces between sand grains.
Male accessory glands (MAG) are the seminal vesicles, prostate gland, and the bulbourethral glands. These glands are found only in mammals. In insects, male accessory glands produce products that mix with the sperm to protect and preserve them, including seminal fluid proteins. Some insecticides can induce an increase in the protein content of the male accessory glands of certain types of insects. This has the unintended effect of increasing the number of offspring they produce.
A trophosome is a highly vascularised organ found in some animals that houses symbiotic bacteria that provide food for their host. Trophosomes are contained by the coelom of tube worms and in the body of symbiotic flatworms of the genus Paracatenula.
Homalometron pallidum is a species of marine trematodes in the family Apocreadiidae. It is an endoparasite of the mummichog, Fundulus heteroclitus, a small fish found in brackish water along the east coast of the United States and Canada. It has a complex life cycle and lives inside several different host species at different stages.
Xenacoelomorpha is a small phylum of bilaterian invertebrate animals, consisting of two sister groups: xenoturbellids and acoelomorphs. This new phylum was named in February 2011 and suggested based on morphological synapomorphies, which was then confirmed by phylogenomic analyses of molecular data.
Most insects reproduce oviparously, i.e. by laying eggs. The eggs are produced by the female in a pair of ovaries. Sperm, produced by the male in one testicle or more commonly two, is transmitted to the female during mating by means of external genitalia. The sperm is stored within the female in one or more spermathecae. At the time of fertilization, the eggs travel along oviducts to be fertilized by the sperm and are then expelled from the body ("laid"), in most cases via an ovipositor.
Microbial symbiosis in marine animals was not discovered until 1981. In the time following, symbiotic relationships between marine invertebrates and chemoautotrophic bacteria have been found in a variety of ecosystems, ranging from shallow coastal waters to deep-sea hydrothermal vents. Symbiosis is a way for marine organisms to find creative ways to survive in a very dynamic environment. They are different in relation to how dependent the organisms are on each other or how they are associated. It is also considered a selective force behind evolution in some scientific aspects. The symbiotic relationships of organisms has the ability to change behavior, morphology and metabolic pathways. With increased recognition and research, new terminology also arises, such as holobiont, which the relationship between a host and its symbionts as one grouping. Many scientists will look at the hologenome, which is the combined genetic information of the host and its symbionts. These terms are more commonly used to describe microbial symbionts.
Waminoa is a genus of acoels which are epizoic on living corals, using the coral's mucus as a source of food. Unusually, these acoels harbor two genera of endosymbiotic dinoflagellates: Symbiodinium and Amphidinium; it is not typical for two different genera of dinoflagellates to coexist in a single host. Waminoa's host coral may also contain dinoflagellates of the genus Symbiodinium but not Amphidinium.
Waminoa litus is a species of dinoflagellate-bearing acoel which is epizoic on living corals. This species is unique in that it transmits its endosymbiotic dinoflagellates (zooxanthellae) vertically via eggs, regardless of the heterogeneity of the zooxanthellae. Two dinoflagellate genera have been found to simultaneously live in the parenchyma of W. litus: Symbiodinium and Amphidinium.
Photosymbiosis is a type of symbiosis where one of the organisms is capable of photosynthesis.