User:JacquiConlon/Abyla (genus)

This article is about the genus Abyla in the Siphonophorae order. If looking for the roman colony Abyla, go to this page.

Abyla is a genus of siphonophore in the subfamily Abylidae which belongs to the suborder Calycophorae. The genus contains three species: Abyla bicarinata, Abyla haeckeli and Abyla trigona. This genus was first founded by Quoy and Gaimard in 1827 and their findings were documented in "Annales des sciences naturelles Zoologie." There is very little information known about siphonophores in general due to them living in the deep sea causing sample collections to be hard. Most will either disintegrate in a net or be dead by the time we have time to analyze them.

Classification History

The genus Abyla used to contain many more species but most have since been reclassified. The only three accepted species within the genus are Abyla bicarinata, Abyla haeckeli and Abyla trigona.

Synonyms

• Abyla brownia (Sears, 1953) and Abyla tottoni (Sears 1953) are accepted as Abyla bicarinata (Moser, 1925)
• Abya ingeborgae (Sears, 1953) is accepted as Abyla haeckeli (Lens and van Riemsdijk, 1908)
• Abyla carina, Abyla peruana and Abyla schimidti are accepted as Abyla trigona

Each one of these three species and their synonyms can be found in scientific literature but the synonyms are not as commonly used.

Anatomy

All species in the Abyla genus are strictly marine. They habit the pelagic zone the most. Colonial siphonophores can grow up to 40 meters and possibly longer, making them one of the longest animals in the world. They feel the same as jellyfish, with a gelatinous texture. Calcycophores are characterized by having two nectophores rather than a pneumatophore.

General Anatomy

Bioluminescence

Bioluminescence is a very common trait amongst all siphonophores. Since so many of this order live in the deep sea or in deeper waters, the evolution of bioluminescence was thought to be a defense mechanism or a way to attract prey. Some organisms contain a bioluminescent lure to attract prey by mimicking other small fish.

Colony Organization

Since siphonophores are made up of smaller zooids forming a colony, many of these zooids will have a specialized function and arranged in a very specific pattern. There are two types of siphonophore zooids, medusae and polyps. There are solitary medusae but they are commonly known as jellyish or anemones. One of the most well known colonial polyps are colonial corals.

Nectophore: A nectophore or "swimming bells" are used for locomotion. They use a expanding and contracting movement to propel the organism through the water column in any direction.

Zooid: A zooid is a single organism within a colonial animal. They are multicellular and in the case of Siphonophores are connected by a a central stalk made up of tissue.

Bracts: A bract is used to help the organism maintain bouyancy. They are specialized for siphonophores but are not in all species.

Gastrozooids: This is a zooid specialized to help the organism feed.

Palpons: These are a variation of gastrozooids that can assist the organism in digestion by moving around gastrovasular fluids.

Gonophores: A gonophore is a zooid specifically used for the reprosuction process.

Pneumatophores are not found in the Abyla genus.

Abyla bicarinata

Anatomy of Abyla bicarinata based on Moser 1925.

Abyla bicarinata was first identified by F. Moser in 1925. His discoveries were documented in the book "Deutsche Südpolar-Expedition 1901-1903."

Based on this Demetrio Boltovskoy and his team created the Zooplankton of the South Atlantic Ocean on the Marine Species Identification Portal, in which an anatomical structure was created for Abyla bicarinata.

A wide anterior nectophore with side ridges creates a wing like appearance and providing wing functions. They are also have rounded edges of facets. There is no transverse ridge between the ventral and apico-ventral facets. On the posterior side the nectophore is both the same width and length reinforcing the round and wing shape. They have combs that contain between 4 and 7 strong ostial teeth.

Anatomy of Abyla haeckeli based on Lens and van Riemsdijk 1908.

Abyla haeckeli

Abyla haeckeli was discovered by Albertine D. Lens and Thea van Riemsdijk in 1908. Their expedition was entitled "The Siphonophora of the Siboga."

Based on this Demetrio Boltovskoy and his team created the Zooplankton of the South Atlantic Ocean on the Marine Species Identification Portal, in which an anatomical structure was created for Abyla haeckeli.

The Abyla haeckeli has a anterior nectophore that is the same width and length but it does not provide wing functions. A transverse ridge separates the ventral facet from the apico-ventral facet. The posterior nectophore can have up to 5 teeth on one comb. It also have lateral ostial teeth that are closer to the dorsal tooth rather than the ventral teeth.

Abyla trigona

Anatomy of Abyla trigona based on Quoy and Gaimard 1827.

Abyla haeckeli was discovered by Quoy and Gaimraid in 1827.Their findings were documented in "Annales des Sciences Naturelles."

Based on this Demetrio Boltovskoy and his team created the Zooplankton of the South Atlantic Ocean on the Marine Species Identification Portal, in which an anatomical structure was created for Abyla trigona.

Abyla trigona has an anterior nectophore that is the same size both broad and wide. It also has very heavy irregular and serrate ridges. The ventral facet is not separated from the apico-ventral facet. The posterior nectophore can have from 4 to 11 teeth on a comb. It also has two rows of very serrated teeth on the basal margin.

Feeding

All siphonophores are carnivorous, feeding on smaller copepods, crustaceans and fish. The gastrozooid on a colony directly impacts the type of prey a siphonophore will eat. Most siphonophores have tentacles attached to the gatrozooids which assists the organism in catching prey. Nematocysts are found in some species which are stinging cells on the tentacles usesd to defense and stunning prey. Many deep-sea siphonophores sit and wait for the prey to come to them. The specific feeding methods of the genus Abyla are not known.

Reproduction

Siphonophore reproduction changes amongst species. The reproduction methods for the genus Abyla are relatively unknown. There are multiple reproduction methods as well.

In some, a single zygote will begin the entire organism. It will become a fertilized egg or a protozooid and starts the budding process which eventually turns into a zooid. This process will repeat until an entire colony of zooids have developed, forming around a central stalk.

Other species reproduce via polyps. These polyps will hold eggs and sperms which will then be released into the water column through the end of the organism. This will allow for the eggs and sperm to fertilize outside fo the organism.

Global Distribution

Alvarino et al published the "Siphonophores of the Pacific with a review od hte World Distribution" in 1971 in which they documented the amount of times a certain species was obtained and where in the world as well where in the water column they inhabited. In this study, they found that the genus Abyla are mainly found in tropico-equitorial and subtropic regions.

Abyla bicarinata have been seen off the southeast coast of Hawaii below the 1000 meter mark during the summer months. It was also spotted off the coast of California at 200 meters. They were also found in the South China Sea during winter. Abyla brownia was also found off the coast of California and Hawaii in the upper 200 meters of the water column and rarely seen below 1000 meters. Abyla tottoni was found only in the northwest areas of the Pacific ocean.

Abyla ingeborgae was seen near the Phillipines and Japan in the upper parts of the water column.

Abyla carina were spotted along the Equatorial region in the upper 200 meters during February and March in the South China Sea. Abyla peruana was only seen twice in the South Pacific. Abyla schmiditi was found near the equator with a few sightings near in the western and central parts of the ocean. These three species are found mainly in tropical waters near the equator.