Lampocteis

Lampocteis is a monotypic genus of comb jellies, the only genus in family Lampoctenidae. Lampocteis cruentiventer, or the bloodybelly comb jelly, is the only species within this new genus. This ctenophore was first collected in the Pacific Ocean off the coast of San Diego, California, in 1979, but was not discussed within the scientific community until 2001.

In comparison to all other lobate ctenophores, the morphology of Lampocteis cruentiventer differs in two distinct ways, as it has blind aboral endings on all of its meridional canals, and has a deep notch between its comb rows. This mesopelagic jelly ranges in color from deep red, purple, or black to pale purple. The bloodybelly comb jelly does not sting and the rows of cilia on its body, called "combs," have a sparkling iridescence. Lampocteis cruentiventer tend to be relatively small in size, ranging from 1.5 to 16 centimeters in length and 1.2 to 10 centimeters in width. The origin of ctenophores has been quite controversial, though one recent study suggests, based on the analysis of fossil evidence, that comb jellies evolved from sessile, polyploid suspension feeders, which would link them to cnidarians.

The name of the new species originates from the Latin words cruentus, meaning "bloodred," and venter, meaning "belly."

Morphology

Body

Ctenophores have a biradial body plan with eight comb rows called ctenes, which are used for locomotion. The comb rows are covered in cilia, each up to 2mm long. The body has 16 ridges, eight of which have comb plates. The remaining eight are located between the comb rows. There are two types of comb rows: subtentacular and substomodaeal. The body has a large indentation between the subtentacular comb rows, level with its infundibulum. It's body features two muscular, bowl shaped lobes at its oral end.

The body of the Lampocteis is fairly compressed on its tentacular axis. The stomodaeal axis is 1.6 times longer than its tentacular axis. Lampocteis specimens have ranged from being 1.5 to 16 centimeters in overall length, and 1.2 to 10 centimeters in width.

The body of this ctenophore is rather firm and its skin is very smooth. While its skin is not completely transparent, the gastrovascular systems of some specimens are visible. Members of the Lampocteis genus range in color from deep red, purple, or black to pale purple. The most common colors for the Lampocteis are red and amber.

The auricles of the organism are short, wide, and very flexible. They do not seem do be able to move. Similar to the auricles, the oral lobes of the Lampocteis are strong and fleshy and are slightly longer than the rest of its body.

One morphological difference that separates the Lampocteis from other jellies is its blind aboral endings on its meridional canals. The oral parts of the meridional canals connect with each other in the oral lobes, which is characteristic of all Lobates. However, the substomodaeal meridional canals lay in the middle of the oral lobes. They are folded in a very complex manner within these lobes, and connected to their counterparts in that same oral lobe, forming blind aboral endings.

Tentacular Apparatus

The tentacle bulbs are white and large in size. They are connected to the tentacle canals and are near the mouth opening of the organism.

Gastrovascular System

The mouth of the jelly is right underneath the origin of the auricles. In the tentacular plane, the mouth looks very narrow. There are tentilla from the tentacle bulbs bordering the mouth. The stomodaeum of the Lampocteis is unique as it is capable of expansion, a feature that no other jellies are known to possess. In the tentacular plane, its stomdaeum is diamond shaped, whereas in the stomodaeal plane, it is flask-shaped. Both the infundibulum and gastrovascular canals are very large. The paragastric canals are also large and are located on the crests of the ridges of the Lampocetis.

Habitat

Lampocteis has been found in the mesopelagic zone of the ocean. The jelly inhabits the deep ocean between 640 to 1130 meters below the surface, although some specimens have been collected from as shallow as 300 meters and as deep as 3,000 meters.

The Lampocteis cruentiventer has only been found in the northern Pacific Ocean, specifically off the coasts of Mexico, California, and Japan. In Mexico, this comb jelly can be found in the Cerralvo and Farallon Basins in the Gulf of California. It has also been found in the Monterey Submarine Canyon off the coast of San Diego, California. The comb jelly is also distributed throughout the western Pacific Ocean, found off the Sanriku Coast of Japan in the Sagami Bay, Suruga Bay, and the Japan Sea.

These jellies have been observed in water between 4 and 9.5 degrees Celsius, with salinity levels between 33.69 and 34.45%. They have been found to withstand varying levels of oxygen.

Predator-Prey Interactions

Members of the Lampocteis genus range in color from deep red, purple, or black to pale purple. These colors assist Lampocteis in avoiding predators as it allows them to appear invisible to their predators.

When the Lampocteis feels threatened, it releases luminescent reddish-brown ink from its vesicles.

The diet of this organism remains unknown, though larval fish feedings were used to ensure successful spawning and embryo development in the Monterey Bay Aquarium ctenophore culture.

Reproduction

Ctenophores are capable of producing egg and sperm at the same time, thus they are classified as spontaneous hermaphrodites.