Order Summary for Coelacanthiformes
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Main Ref |
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Order |
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Coelacanthiformes coelacanths |
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Class |
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Coelacanthi |
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Sister Order |
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Ceratodontiformes 400 M years |
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Ref. |
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First Fossil Record |
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early Devonian |
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Occurs in |
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Marine |
Fresh |
Brackish |
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Remark |
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Two dorsal fins, each with a single proximal skeletal element; first dorsal fin sail-like, the membrane supported by bony spines or segmented fin-rays; second dorsal fin, anal fin and the paired (pectoral and pelvic) fins with a muscular basal lobe projecting from the body and containing several cartilaginous or bony skeletal elements. Notochord a well-developed, thick-walled tube filled with fluid in adult (In most other fishes, the notochord is replaced in the developing embryo by bony vertebral centra).
Contrary to "conventional wisdom" the name "coelacanth" (meaning "hollow spine") is not derived from the hollow notochord which serves as a spinal column for these fishes. The term was originally published as a generic name for the fossil coelacanths because of the hollow, elongated, posterior neural and haemal spines that articulate with the caudal fin rays. |
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Class etymology |
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Greek sark, sarx = flesh + Greek pterygion, diminutive of pteryx = wing, fin. Ref. 45335. |
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Order etymology |
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Greek, koilos = cavity + Greek, acantha = thorn or prickle, in refernce to hollow, elongated, posterior neural and haemal spines that articulate with the caudal fin rays. |
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Families |
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( n = 1 ) Latimeriidae |