Sphyrna gilberti
| Sphyrna gilberti | ||||||||||||
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| Scientific name | ||||||||||||
| Sphyrna gilberti | ||||||||||||
| Quattro , Driggers , Grady , Ulrich & MA Roberts , 2013 |
Sphyrna gilberti is a cryptic species from the hammerhead shark family(Sphyrnidae), which can hardly be distinguished from the bow-fronted hammerhead shark ( Sphyrna lewini ). After a DNA analysis and accurate comparisons of morphology uncovering evidence that this is a new species, it was in August 2013 described . The holotype and paratypes are young sharks thatwere caughtin Bulls Bay on the South Carolina coast. The species was named after the ichthyologist Carter R. Gilbert, who noticed an unusual hammerhead specimen that was caught near Charleston in 1967. This was probably the first catch of Sphyrna gilberti .
features
Sphyrna gilberti has an elongated body with a round to oval, increasingly triangular cross-section towards the tail. The hammer-shaped head is flattened, reaches a width of 25 to 32% of the standard length and a length of more than 20% of the standard length, which corresponds approximately to the distance between the two dorsal fins. The cephalofoil (the greatly enlarged head) has a median indentation. The inner edge of the pelvic fins is smooth. The number of precaudal vertebrae (vertebrae in front of the caudal spine) is 83 to 91, with only one specimen having more than 87 precaudal vertebrae. Sphyrna gilberti is gray to brown on the upper side, towards the whitish belly the color becomes increasingly pale. The tip of the pectoral fins is white or dark (in 60% of the specimens). The lower caudal fin lobe has a dark gray to black tip.
The maximum size of the species described using juvenile fish is unknown. Since newborn specimens with an unlocked navel were 39.7 to 45.1 cm in length, smaller than newborns of the bow-forehead hammerhead, it is assumed that Sphyrna gilberti is not the maximum size of the 3.7 to 4.3 meters long Bow-forehead hammerhead reached.
distribution
The exact distribution area of Sphyrna gilberti is unknown. All specimens known so far come from the north-western Atlantic off the coast of South Carolina. However, there are indications that the species also occurs in the western South Atlantic.
literature
- Joseph M. Quattro, William B. Driggers III, James M. Grady, Glenn F. Ulrich & Mark A. Roberts: Sphyrna gilberti sp. nov., a new hammerhead shark (Carcharhiniformes, Sphyrnidae) from the western Atlantic Ocean . In: Magnolia Press (ed.): Zootaxa . 3702, No. 2, Wellington, New Zealand, Aug. 26, 2013, pp. 159-178. doi : 10.11646 / zootaxa.3702.2.5 .
Web links
Sphyrna gilberti on Fishbase.org (English)