วันศุกร์ที่ 26 สิงหาคม พ.ศ. 2554

Footballfish


The footballfish are a family, Himantolophidae, of globose, deep-sea anglerfishes found in tropical and subtropical waters of the Atlantic, Indian, and Pacific Ocean. As in other deep-sea anglerfish families, sexual dimorphism is extreme: the largest females may exceed lengths of 60 cm (two feet) and are globose in shape, whereas males do not exceed 4 cm (1.5 inches) as adults and are comparatively fusiform. Both are a reddish brown to black in life.
In both sexes, the fins are spineless: the single dorsal fin with 5 – 6 soft rays, the pectoral fins with 14 – 18, the anal fin with four, and the caudal fin with 19. There are six branchiostegal rays and 19 vertebrae; the parietal is lacking throughout life, there are no epurals, and the pelvic bone is triradiate.  
The football fish was first discovered in the early 1900s by deep sea fisherman in search of flounder.Their poor musculature and cumbersome morphology indicate that female footballfish at least are probably poor swimmers and largely sedentary, lie-in-wait predators. They are primarily mesopelagic, living in open water, with very few caught below 1,000 m (3,280 ft). Females are carnivorous and feed upon other pelagic fish (such as lanternfishes and ridgeheads) and cephalopods, as well as shrimp and euphausiids. Upon maturity, the tiny males of most species metamorphose into a parasitic form, which lacks both a lure and true teeth and is presumed not to feed. The parasitic males use their enlarged olfactory bulbs (as indicated by their enlarged nostrils) and sensitive eyes to home in on the pheromones and possibly the species-specific lures of mature females, as is the case in other ceratioid anglerfish families.
Footballfish are presumed to be non-guarders and to spawn pelagically. Their larvae are epipelagic (occurring in the well-lit 200 m of the water column), indicating they probably undergo an ontogenetic descent into deeper waters as the larvae mature. Predators of footballfish include Sperm Whales and other footballfish. 

Humans do not use the fish, but scientists are attempting to use the shape of the fish to advance deep sea exploration.

From: http://en.wikipedia.org/wiki/Footballfish


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