Phylogeny and Evolution
The first efforts to determine the evolutionary relationships of the copper shark were based on morphology and returned inconclusive results: in 1982 Jack Garrick placed it by itself as a grouping within Carcharhinus, while in 1988 Leonard Compagno placed it in an informal "transitional group" that also contained the blacknose shark (C. acronotus), the blacktip reef shark (C. melanopterus), the nervous shark (C. cautus), the silky shark (C. falciformis), and the night shark (C. signatus). Gavin Naylor's 1992 allozyme study concluded that the closest relative of the copper shark is the spinner shark (C. brevipinna), but could not resolve their wider relationships with the rest of the genus. Fossilized teeth from the copper shark have been recovered from the Pungo River in North Carolina, dating to the Miocene (23–5.3 Ma), from Tuscany, dating to the Pliocene (5.3–2.6 Ma), and from Costa Mesa in California, dating to the Late Pleistocene (126,000–12,000 years ago).
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