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Elasmobranchii is one of the two subclasses of cartilaginous fish in the class Chondrichthyes, the other being Holocephali . Members of the elasmobranchii subclass have no swim bladders, five to seven pairs of gill clefts opening individually to the exterior, rigid dorsal fins, and small placoid scales. The teeth are in several series; the ...
Elasmobranchii is a subclass that includes the sharks and the rays and skates. Members of the elasmobranchii have no swim bladders, five to seven pairs of gill clefts opening individually to the exterior, rigid dorsal fins, and small placoid scales. The teeth are in several series; the upper jaw is not fused to the cranium, and the lower jaw is ...
They and their close relatives, the sharks, compose the subclass Elasmobranchii. Rays are the largest group of cartilaginous fishes, with well over 600 species in 26 families. Rays are distinguished by their flattened bodies, enlarged pectoral fins that are fused to the head, and gill slits that are placed on their ventral surfaces.
Reproduction is aplacental viviparous, with females gestating two or three young at a time. The dwarf lanternshark is not significant to commercial fisheries, but could be threatened by mortality from bycatch; the degree of impact from human activities on its population is unknown.
The smooth lanternshark's slow rates of reproduction and growth may render it vulnerable to population collapse under sustained fishing pressure. [8] However, catch rates currently show no evidence of this occurring, which, coupled with the smooth lanternshark's wide geographic range, has led to the IUCN assessing it as of Least Concern . [ 1 ]
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Scyliorhinidae catsharks may be distinguished by their elongated, cat-like eyes and two small dorsal fins set far back. Most species are fairly small, growing no longer than 80 cm (31 in); a few, such as the nursehound (Scyliorhinus stellaris) can reach 1.6 m (5.2 ft) in length.
Prey choice is therefore limited by the size of the mouth. [28] A 1.3 m (4.3 ft) sawfish had a 33 cm (13 in) catfish in its stomach. [76] It had been suggested that sawfish use their saw to dig/rake in the bottom for prey, [84] but this was not observed during a 2012 study, [79] or supported by later hydrodynamic studies. [82]