Fig 1.
Map of Florida, USA showing collection localities for shells of the Florida Horse Conch, Triplofusus giganteus, used for stable isotope sclerochronology.
Fig 2.
Stable oxygen and carbon isotope profiles.
Oxygen (darker lines) and carbon (lighter lines) stable isotope sclerochronology profiles for Triplofusus giganteus shells. A. Specimen Tg-A (BMSM 119422) from the Dry Tortugas, Florida Keys. B. Specimen Tg-B (BMSM 119423) from Vaca Key, Florida Keys. C. Specimen Tg-C from Cape Romano, Florida. Positions of summers (S) are indicated at cycle peaks. Years are shown as alternating grey and white bands. Line colors correspond to growth curve colors in Fig 4.
Fig 3.
Counts of opercular striae and adventitious layers.
Opercula showing annual striae (A, B, D) on external surface and interior adventitious layers (E). A, C, D. Specimen Tg-A (BMSM 119422) from the Dry Tortugas, Florida Keys. B. Specimen Tg-C from Cape Romano, Florida. White lines indicate annual striae and adventitious layers. Arrows mark sharp ledges of annual striae on the external surface.
Fig 4.
Triplofusus giganteus growth curves.
Growth curves for Tg-A, Tg-B, Tg-C (this study), and a male specimen Tg-S [from Strauss et al., 21] modeled with spiral-length-at-age data from oxygen isotope profiles. The horizontal dotted line represents the measured spiral length of the record size shell. Vertical lines are placed at the intersection of growth curves with this horizontal line to show how long it would take for observed growth patterns in T. giganteus to produce the record shell size.