Winghead shark
Eusphyra blochii, presentation of 1889
The wing head Hammerhead ( Eusphyra blochii ) belongs to the family of hammerhead sharks ( Sphyrnidae ). In this hammerhead especially the very pronounced broadening of the head, the Cephalofoil is striking because its expansion is approximately equal to half the body length.
Physique
The wing head Hammerhead is one of the comparatively small species of hammerhead sharks with a maximum body length of 186 inches, the average length is about 120 and 140 centimeters. It is characterized by a particularly wide pronounced Cephalofoil that is created considerably broader with a width of 40 to 50 percent of the body length than any other hammerhead sharks. It is also very narrow and has on the front greatly enlarged nostrils, where the distance the 1.1 - to 1.3 - times the length of the nostril diameter makes during this with all other species, the 7 - to 14 - times the length of the nose hole diameter is. The eyes are on the sides at the end of Cephalofoil and are round or almost round.
The anterior dorsal fin is at the base of the pectoral fins and is thus slightly further forward than other hammerhead sharks.
Dissemination
The wing head Hammerhead is found in tropical waters of the Pacific Ocean and the Indian Ocean ( between latitudes 31 ° N and 20 ° S) mainly near the coast of the continental shelf. The range extends from the Red Sea over the entire South Asian coast of the Indian Ocean to northern China and Japan, and the entire Indo-Pacific area of Southeast Asia to the north coast of Australia.
Reproduction
The wing head Hammerhead is viviparous. The young generation is growing up in the uterus of the mother and feeds to the birth of a yolk sac placenta. The gestation period is about 11 months, the females give birth then between six and nine pups. Between bearing female rivals fighting sharks were observed. Since distinguishes the shark already as a young animal with an extremely broad head, the two head wings are prenatally to the body and unfold until after birth.
System
Sphyrna tiburo
Sphyrna corona
Sphyrna media
Sphyrna tudes
Sphyrna mokarran
Sphyrna zygaena
Sphyrna lewini
Eusphyra blochii
Eusphyra blochii
Sphyrna mokarran
Sphyrna zygaena
Sphyrna lewini
Sphyrna tiburo
Sphyrna corona
Sphyrna tudes
Sphyrna media
It was originally thought that developed the broadening of the head gradually, with the Spatennasenhai ( Scoliodon laticaudus ) was considered within the requiem sharks as a sister species to the hammerheads. According to this idea marks the bonnethead hammerhead is the most primitive type of hammerhead sharks, while the wing head Hammerhead was seen with his very strong sweeping Cephalofoil as highly derived type.
However, on the basis of phylogenetic analyzes of morphological and molecular biological characteristics ( isozymes and mitochondrial DNA) could be demonstrated that the wing head Hammerhead is the most original character within the hammerheads and within the genus Sphyrna species with a very large trained Cephalofoil ( Great hammerhead, smooth hammerhead and scalloped hammerhead ) are to be regarded as particularly original. The position of the species is particularly flaring Cephalofoil could also be confirmed by further studies in 2010.
This suggests that within the hammerheads with a large Cephalofoil represent the initial state, the large species and the smaller species with narrower heads derived from these. Regarding the height close Lim et al. 2010 as a result of their relationship hypothesis and the distribution of the species that the most original hammerhead sharks were large species, of which derive both the small wing head hammerhead Sphyrna as well as the smaller species.
Endangering
The wing head Hammerhead is in the IUCN Red List as Near Threatened ( Near Threatened, early warning ) classified.