The Echiura, or spoon worms, are a small group of marine animals. Once treated as a separate phylum, they are now considered to belong to Annelida. Annelids typically have their bodies divided into segments, but echiurans have secondarily lost their segmentation. The majority of echiurans live in burrows in soft sediment in shallow water, but some live in rock crevices or under boulders, and there are also deep sea forms. More than 230 species have been described. Spoon worms are cylindrical, soft-bodied animals usually possessing a non-retractable proboscis which can be rolled into a scoop-shape to feed. In some species the proboscis is ribbon-like, longer than the trunk and may have a forked tip. Spoon worms vary in size from less than a centimetre in length to more than a metre.
Ctenophora comprise a phylum of marine invertebrates, commonly known as comb jellies, that inhabit sea waters worldwide. They are notable for the groups of cilia they use for swimming, and they are the largest animals to swim with the help of cilia.
Monterey Bay Aquarium is a nonprofit public aquarium in Monterey, California. Known for its regional focus on the marine habitats of Monterey Bay, it was the first to exhibit a living kelp forest when it opened in October 1984. Its biologists have pioneered the animal husbandry of jellyfish and it was the first to successfully care for and display a great white shark. The organization's research and conservation efforts also focus on sea otters, various birds, and tunas. Seafood Watch, a sustainable seafood advisory list published by the aquarium beginning in 1999, has influenced the discussion surrounding sustainable seafood.
Ecdysozoa is a group of protostome animals, including Arthropoda, Nematoda, and several smaller phyla. They were first defined by Aguinaldo et al. in 1997, based mainly on phylogenetic trees constructed using 18S ribosomal RNA genes. A large study in 2008 by Dunn et al. strongly supported the Ecdysozoa as a clade, that is, a group consisting of a common ancestor and all its descendants.
Panarthropoda is a proposed animal clade containing the extant phyla Arthropoda, Tardigrada and Onychophora. Panarthropods also include extinct marine legged worms known as lobopodians ("Lobopodia"), a paraphyletic group where the last common ancestor and basal members (stem-group) of each extant panarthropod phylum are thought to have risen. Although the term "Lobopodia" is sometimes expanded to include tardigrades and onychophorans as well.
Bioluminescence is the production and emission of light by living organisms. It is a form of chemiluminescence. Bioluminescence occurs widely in marine vertebrates and invertebrates, as well as in some fungi, microorganisms including some bioluminescent bacteria, and terrestrial arthropods such as fireflies. In some animals, the light is bacteriogenic, produced by symbiotic bacteria such as those from the genus Vibrio; in others, it is autogenic, produced by the animals themselves.
A nerve net consists of interconnected neurons lacking a brain or any form of cephalization. While organisms with bilateral body symmetry are normally associated with a condensation of neurons or, in more advanced forms, a central nervous system, organisms with radial symmetry are associated with nerve nets. Nerve nets can be found in members of the Ctenophora, Cnidaria, and Echinodermata phyla, all of which are found in marine environments. Nerve nets can provide animals with the ability to sense objects through the use of the sensory neurons within the nerve net.
Siphonophorae is an order within Hydrozoa, which is a class of marine organisms within the phylum Cnidaria. According to the World Register of Marine Species, the order contains 175 species.
Milky seas, also called mareel, is a luminous phenomenon in the ocean in which large areas of seawater appear to glow translucently. Such occurrences glow brightly enough at night to be visible from satellites orbiting Earth.
Scalidophora is a group of marine pseudocoelomate protostomes that was proposed on morphological grounds to unite three phyla: the Kinorhyncha, the Priapulida and the Loricifera. The three phyla have four characters in common — chitinous cuticle that is moulted, rings of scalids on the introvert, flosculi, and two rings of introvert retracts. However, the monophyly of the Scalidophora is not supported by molecular studies, where the position of the Loricifera was uncertain or as sister to the Panarthropoda. Both studies supported a reduced Scalidophora comprising the Kinorhyncha and Priapulida as sister phyla. Their closest relatives are the Panarthropoda, Nematoda and Nematomorpha; thus, they are placed in the group Ecdysozoa.
Davidson Seamount is a seamount located off the coast of Central California, 80 mi (129 km) southwest of Monterey and 75 mi (121 km) west of San Simeon. At 26 mi (42 km) long and 8 mi (13 km) wide, it is one of the largest known seamounts in the world. From base to crest, the seamount is 7,480 ft (2,280 m) tall, yet its summit is still 4,101 ft (1,250 m) below the sea surface. The seamount is biologically diverse, with 237 species and 27 types of deep-sea coral having been identified.
Gelatinous zooplankton are fragile animals that live in the water column in the ocean. Their delicate bodies have no hard parts and are easily damaged or destroyed. Gelatinous zooplankton are often transparent. All jellyfish are gelatinous zooplankton, but not all gelatinous zooplankton are jellyfish. The most commonly encountered organisms include ctenophores, medusae, salps, and Chaetognatha in coastal waters. However, almost all marine phyla, including Annelida, Mollusca and Arthropoda, contain gelatinous species, but many of those odd species live in the open ocean and the deep sea and are less available to the casual ocean observer. Many gelatinous plankters utilize mucous structures in order to filter feed. Gelatinous zooplankton have also been called "Gelata".
The Myriochelata or Paradoxopoda, is a proposed grouping of arthropods comprising the Myriapoda and Chelicerata. If this proposition holds true, the Myriochelata are the sister clade to the Pancrustacea, comprising classic crustaceans and hexapods.
A bottom feeder is an aquatic animal that feeds on or near the bottom of a body of water. Biologists often use the terms benthos—particularly for invertebrates such as shellfish, crabs, crayfish, sea anemones, starfish, snails, bristleworms and sea cucumbers—and benthivore or benthivorous, for fish and invertebrates that feed on material from the bottom. However the term benthos includes all aquatic life that lives on or near the bottom, which means it also includes non-animals, such as plants and algae. Biologists also use specific terms that refer to bottom feeding fish, such as demersal fish, groundfish, benthic fish and benthopelagic fish. Examples of bottom feeding fish species groups are flatfish, eels, cod, haddock, bass, grouper, carp, bream (snapper) and some species of catfish and shark.
The term deep sea creature refers to organisms that live below the photic zone of the ocean. These creatures must survive in extremely harsh conditions, such as hundreds of bars of pressure, small amounts of oxygen, very little food, no sunlight, and constant, extreme cold. Most creatures have to depend on food floating down from above.
The Spiralia are a morphologically diverse clade of protostome animals, including within their number the molluscs, annelids, platyhelminths and other taxa. The term Spiralia is applied to those phyla that exhibit canonical spiral cleavage, a pattern of early development found in most members of the Lophotrochozoa.
Edith Anne "Edie" Widder Smith is an American oceanographer, marine biologist, author and the Co-founder, CEO and Senior Scientist at the Ocean Research & Conservation Association.
ParaHoxozoa is a clade of animals that consists of Bilateria, Placozoa, and Cnidaria. The relationship of this clade relative to the two other animal lineages Ctenophora and Porifera is debated. Some phylogenomic studies have presented evidence supporting Ctenophora as the sister to Parahoxozoa and Porifera as the sister group to the rest of animals. Some studies have presented evidence supporting Porifera as the sister to Parahoxozoa and Ctenophora as the sister group to the rest of animals. The tree below, which is congruent with the vast majority of these phylogenomic studies, conveys this uncertainty with a polytomy.
Gregory Donald Edgecombe is a merit researcher in the department of Earth Sciences at the Natural History Museum, London. He is a leading figure in understanding the evolution of arthropods, their position in animal evolution and the integration of fossil data into analyses of animal phylogeny. As a palaeontologist, he is also an authority on the systematics of centipedes – and a morphologist whose work contributes to the growth and methods of analysis of molecular datasets for inferring evolutionary relationships.
Emplectonema kandai is a marine ribbon worm, found in the Aomori Bay at a depth of 35–40 meters, and coiled up on Chelyosoma sea squirts. They are reddish orange in color. They have many eyes. They vary in length, from 53–115 cm, and are about 0.5-0.7 mm in diameter, when they are stretched. It is the only currently known bioluminescent member of the genus Emplectonema, and furthermore is currently the only known bioluminescent ribbon worm. E. kandai flash brilliantly in an internal (non-secreted) luminescence, but only on stimulation. The stimulus may be mechanical, chemical, thermal or electrical. The color of their luminescence is whitish-green.
