User:Kevinbr41/Hippopus Hippopus

Description
Hippopus Hippopus, also known as the Horse Hoof clam and Strawberry clam, is a species of Giant Clam in the Family Tridacna and the family Hippopus. Hippopus Hippopus is delicacy in many southeast asian countries due to its high quality meat.

Distribution and Habitat
Hippopus Hippopus is found in tropical waters of the Indian and Pacific ocean. Hippopus Hippopus is commonly found on the coast of Indonesia and Palau. Its range extends as far as India in the Indian Ocean, and Kiribati in the Pacific ocean.

Hippopus Hippopus is frequently inhabiting the shallow waters of fringing, barrier reefs, and seagrass beds. Hippopus Hippopus inhabits the shallow water so that its simbiotic inhabitants can use sunlight to perform phoyosynthesis for the clam. Hippopus does not attach to rocks in the reef, instead, they settles on sandy patches, detached from any rocks.

Conservation
Due to its shallow habitat, Hippopus Hippopus is very easy to access, causing for high volumes of clams to be harvested yearly. As a result, its population has declined significantly, and is threatened according to the IUCN red list. Hippopus Hippopus has become extinct off the coast of countries such as American Samoa, Fiji, Guam, Japan, Northern Mariana Islands, Samoa, Taiwan, China, and Tonga.

Anatomy and Morphology
The shell of hippopus hippopus is characterized as having strawberry blotches in the shape of bands on the exterior of the shell. Their mantle is a green-yellow color, with tighly fitting interlocking ridges. The shape of the shell if sub-rhomboidal and bears deeps ridges that stretch vertically across the surface of the shell. In comparison to its cousins, Hippopus Hippopus is relatively average in size, averaging 22 cm (8.66 in) and reaching maximums lengths of 45 cm (17.72 in). The hinge of Hippopus unlike other bivalves, is adjacent to the substrate, with the inhalant siphon and mantle tissues facing towards the surface of the water. This maximizes the photosynthetic capapbilities of the photosynthetic dinoflagellates that harvest the suns rays, producing the clams distinct vibrant pigmentation.

Tubular System
Hippopus Hippopus relies heavily on photosynthetic dinoflagellates called zooxanthellae for nutrition. About 65 to 70 percent of a giant clams nutrition is derived from zooxanthellae. These dinoflagellates are found in the siphonal mantle, and inside a vast tubular system. This tubular system starts at the stomach, where one primary zooxanthellae tube moves through and away from the stomach, braching into two zooxanthellae tubes at the clam's digestive system. Both tubes then travel to the root of the siphonal mantle, where both secondary tubes branch into numerous tertiary zooxanthellae branches. This bast system of tubes allows the zooxanthellae to communicate with the clams stomach thorugh a small opening. A clam's simbiotic relationship with dinoflagellates is unique because the zooxanthellae has a direct relationship with the digestive system of its host.

Filter Fedding
Hippopus Hippopus also acquires nutrients through filter feeding, using its inhalant siphon to eat marine microorganisms such as phyto plankton and zooplankton by catching them on cilited tracts on their gill plates. The amount of carbon a clam acquires using this mechanism is determined by the size of the clam, with smaller clams acquiring approximately 60 percent fo its carbon from this method, and larger clams receiving approximately 34 percent from filter feeding plankton.

Reproduction
Hippopus Hippopus are protandrous hermaphrodites, first developing male gonads, eventually becoming a hermaprodite after the development of females gonadal cells. To reproduce, sperm is first released into the water column, then eggs are expelled and fertilised. This expulsion of reproductive cells will also trigger other clams to expel sperms and eggs cells, increasing the probability that eggs are fertilised in the water column. Egg cells have been found to be viable for approximately 4 to 6 hours, which causes larger communities of hipopus hippopus to have higher reproductive success due to a higher volume of reproductive cells.

Development
The larvae then goes through a plantonic stage, where a juvenile hippopus hippopus meroplankton is free swimming, developing cilium for locomotion. As the larvae grow, the clam looks for a suitable place to settle, while additionally beginning to develop its foot organ and bivalve shell. Hippopus Hippopus settles on sandy substrate, unlike its cousins in the genus Tridacna, which attaches itself to a rocky substrate. After 6 to 14 days, the development of a muscular foot causes metamorphoses to a benthic lifestyle. Hippopus Hippopus then begins to crawl to find an optimal substrate. Once found, the clam loses its locomotion, and procedes to live a sessile lifestyle. After 25 days, juvenile Hippopus Hippopus acquire zooxanthellae, which causes a sharp incline in growth due to a new source of food for the clam.