mackerel sharks
Characteristic features:
- Teeth long and few in number
- Second dorsal and anal fin much smaller than first dorsal fin
- Caudal peduncle strongly depressed dorsoventrally
- A single prominent lateral keel on each side of caudal peduncle
- Caudal fin lunate, upper and lower lobes of similar length
- Intestinal valve ring type
Keys:
Lamnidae (adapted from Collette, 2001)
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- Origin of first dorsal fin level with or slightly forward of pectoral-fin rear tips (Fig. 1a); anal-fin origin behind second dorsal-fin base (Fig. 2a); upper teeth with triangular and strongly serrated cusps (Fig. 3a)Carcharodon carcharias (great white shark)
- Origin of first dorsal fin level behind pectoral-fin rear tips (Fig. 1b); anal-fin origin below midbase or insertion of second dorsal fin (Fig. 2b,c); upper teeth with narrow and smooth-edged cusps (Fig. 3b, c)2
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- Snout acutely pointed, it’s under surface white (Fig. 4a); pectoral fins much shorter than head, tips narrowly to acutely pointed (Fig. 5a); anal-fin origin about level with midbase of second dorsal fin (Fig. 2b); cusps of upper and lower anterior teeth recurved at bases but with tips reversed and curving outwards (Fig. 6a)Isurus oxyrinchus (shortfin mako)
- Snout narrowly to bluntly pointed, its undersurface dusky (Fig. 4b); pectoral fins about as long as head, more broadly tipped (Fig. 5b); anal-fin origin about level with second dorsal-fin insertion (Fig. 2c); cusps of upper and lower anterior teeth straighter, with tips not reversed (Fig. 6b)Isurus paucus (longfin mako)
Similar families:
Carcharhinidae
Carcharhinidae differ in having well-developed nictitating lower eyelids (vs. no nictitating lower eyelids ); a strongly asymmetrical caudal fin with the upper lobe longer than the lower (vs. caudal fin lunate and near symmetrical, upper and lower lobes of similar length); a caudal peduncle not greatly flattened dorsoventrally (vs. caudal peduncle strongly flattened dorsoventrally and expanded laterally); a longitudinal keel on caudal peduncle weak (Prionace glauca) or absent (vs. prominent, extending well out from peduncle) and intestinal valve scroll type (vs. ring type).
