Morphological Variation Among Bowfin (Amia) Populations from the Carolinas and Laurentian Great Lakes: Taxonomic and Conservation Implications

The genus Amia has been considered monotypic since 1896, when 12 nominal species were synonymized with A. calva without analysis or rationale. To test that monotypy hypothesis, we analyzed morphological variation between two regions, focusing on newly collected topotypical specimens: 1) South Carolina (type localities of A. calva, A. lentiginosa and A. cinerea) and 2) Great Lakes (type localities of A. ocellicauda, A. occidentalis, and A. canina). We also examined all available type materials for Amia spp.  Results revealed significant morphological differences among these populations; we reject the 120-year-old monotypy hypothesis.  Several characters distinguish South Carolina bowfins from those in lakes Erie and Huron, including: 1) less lateral-line scales; 2) Less dorsal fin-rays; and 3) Pelvic fins relatively shorter in Carolinas. Bowfins from Lakes Huron and Erie also differed, with L. Huron fishes having: 1) More pelvic fin-rays; 2) Longer caudal peduncle: and 3) Narrower head width. The second Bowfin species to be described was A. ocellicauda from L. Huron; it seems likely that nominal taxon may need to be reconsidered. Distinction of the L. Erie population also suggests further taxonomic complexity needing analysis. Discovery of a second bowfin species raises conservation concerns, given the developing bowfin caviar fishery.