Seahorse in the context of "Pygmy seahorse"

A seagrass meadow or seagrass bed is an underwater ecosystem formed by seagrasses. Seagrasses are marine (saltwater) plants found in shallow coastal waters and in the brackish waters of estuaries. Seagrasses are flowering plants with stems and long green, grass-like leaves. They produce seeds and pollen and have roots and rhizomes which anchor them in seafloor sand.

Seagrasses form dense underwater meadows which are among the most productive ecosystems in the world. They provide habitats and food for a diversity of marine life comparable to that of coral reefs. This includes invertebrates like shrimp and crabs, cod and flatfish, marine mammals and birds. They provide refuges for endangered species such as seahorses, turtles, and dugongs. They function as nursery habitats for shrimps, scallops and many commercial fish species. Seagrass meadows provide coastal storm protection by the way their leaves absorb energy from waves as they hit the coast. They keep coastal waters healthy by absorbing bacteria and nutrients, and slow the speed of climate change by sequestering carbon dioxide into the sediment of the ocean floor.

The hippocampus (pl.: hippocampi; via Latin from Greek ἱππόκαμπος, 'seahorse'), also hippocampus proper, is a major component of the brain of humans and many other vertebrates. In the human brain the hippocampus, the dentate gyrus, and the subiculum are components of the hippocampal formation located in the limbic system. The hippocampus plays important roles in the consolidation of information from short-term memory to long-term memory, and in spatial memory that enables navigation. In humans and other primates the hippocampus is located in the archicortex, one of the three regions of allocortex, in each hemisphere with direct neural projections to, and reciprocal indirect projections from the neocortex. The hippocampus, as the medial pallium, is a structure found in all vertebrates.

In Alzheimer's disease (and other forms of dementia), the hippocampus is one of the first regions of the brain to be damaged; short-term memory loss and disorientation are included among the early symptoms. Damage to the hippocampus can also result from oxygen starvation (hypoxia), encephalitis, or medial temporal lobe epilepsy. People with extensive, bilateral hippocampal damage may experience anterograde amnesia: the inability to form and retain new memories.

An upright posture or erect posture is the state of an animal's body where its craniocaudal axis is perpendicular (vertical) to the ground and to the direction it is facing/moving. Examples of such postures include some tetrapods with bipedal gait and the swimming posture of seahorses.

Teleostei (/ˌtɛliˈɒstiaɪ/; Greek teleios "complete" + osteon "bone"), members of which are known as teleosts (/ˈtɛliɒsts, ˈtiːli-/), is, by far, the largest group of ray-finned fishes (class Actinopterygii), with 96% of all extant species of fish. The Teleostei, which is variously considered a division or an infraclass in different taxonomic systems, include over 26,000 species that are arranged in about 40 orders and 448 families. Teleosts range from giant oarfish measuring 7.6 m (25 ft) or more, and ocean sunfish weighing over 2 t (2.0 long tons; 2.2 short tons), to the minute male anglerfish Photocorynus spiniceps, just 6.2 mm (0.24 in) long. Including not only torpedo-shaped fish built for speed, teleosts can be flattened vertically or horizontally, be elongated cylinders or take specialised shapes as in anglerfish and seahorses.

The difference between teleosts and other bony fish lies mainly in their jaw bones; teleosts have a movable premaxilla and corresponding modifications in the jaw musculature which make it possible for them to protrude their jaws outwards from the mouth. This is of great advantage, enabling them to grab prey and draw it into the mouth. In more derived teleosts, the enlarged premaxilla is the main tooth-bearing bone, and the maxilla, which is attached to the lower jaw, acts as a lever, pushing and pulling the premaxilla as the mouth is opened and closed. Other bones further back in the mouth serve to grind and swallow food. Another difference is that the upper and lower lobes of the tail (caudal) fin are about equal in size. The spine ends at the caudal peduncle, distinguishing this group from other fish in which the spine extends into the upper lobe of the tail fin.

Pipefishes or pipe-fishes (Syngnathinae) are a subfamily of small fishes, which, together with the seahorses and seadragons (Phycodurus and Phyllopteryx), form the family Syngnathidae. The name comes from Ancient Greek σύν (sún), meaning "together", and γνάθος (gnáthos), meaning "jaw", referring to the fused jaw that the subfamily's species have in common.

The leafy seadragon (Phycodurus eques) or Glauert's seadragon, is a marine fish. It is the only member of the genus Phycodurus in the family Syngnathidae, which includes seadragons, pipefish, and seahorses.

It is found along the southern and western coasts of Australia. The name is derived from their appearance, with long leaf-like protrusions coming from all over the body. These protrusions are not used for propulsion; they serve only as camouflage. The leafy seadragon propels itself utilising a pair of pectoral fins on the sides of its neck and a dorsal fin on its back closer to the tail end. These small fins are almost completely transparent and difficult to see as they undulate minutely to move the creature sedately through the water, completing the illusion of floating seaweed.

Phyllopteryx is a genus of small fishes, commonly called seadragons, in the family Syngnathidae that are found along the western and southern coasts of Australia. Since the 19th century, the weedy or common seadragon was the only known species, until the description of the ruby seadragon in 2015. They are closely related to other members of the Syngnathidae such as the leafy seadragon, pipefish and seahorses, which all exhibit male pregnancy.

The Syngnathidae is a family of fish which includes seahorses, pipefishes, and seadragons (Phycodurus and Phyllopteryx). The family name comes from Ancient Greek σύν (sún), meaning "together", and γνάθος (gnáthos), meaning "jaw", referring to the fused jaw that the entire family have in common.