Sharks and Rays of Florida: a 45-million-year history Victor J. Perez Assistant Curator of Paleontology Calvert Marine Museum Chondrichthyan Tree of Life Modern Cartilaginous Fish • Sharks (>500 species) • Rays (>600 species) • Chimaera (>50 species) Modern Florida Diversity Summary >100 species 11 orders 35 families 54 genera Artist: Sebastien Guyonneau (O’Khaen) Chondrichthyan Tree of Life Project (www.sharksrays.org) Project Origins Driving Question: How has shark and ray diversity changed around the Florida platform? Florida Museum How can we measure biodiversity? 1. Species Richness: The number of species in a specific time and place 2. Species Evenness: The relative abundance of different species in a specific time and place What factors affect fossil diversity? Physical Biological Preservation Collection Effort Ex. Climate Change Ex. Competition Ex. Rock Type Ex. Screenwashing Actual Diversity Trends Biased Diversity Trends Shark Diversity along Calvert Cliffs Visaggi and Godfrey (2010) Florida Surficial Geology Age Range: o Eocene to Present (~48 million years to now) Rock Type: o Sedimentary rocks o Carbonate (Limestone) o Siliciclastic (Sand and Clay) Florida geologic map (Scott et al., 2001). Environmental and Depositional Transition 48 – 34 Ma 34 – 23 Ma 23 – 2.6 Ma Florida was a shallow marine Florida emerges from the sea, Florida connects to the rest of environment, separated from as global temperature drops. the United States. Siliciclastic land by a deep-water channel. Transition in sediment type. deposition ramps up. Adapted from Florida Formations: Shifting Seas and Sediments exhibit, Gillespie Museum, Stetson University. Where do we find fossils in Florida? Beaches! Rivers and streams! Ancient sinkholes! Mines! Construction Sites! FLMNH Specify Database 117,353 specimens 77 taxa (original) 65 taxa (corrected) 10 orders 26 families Oldest Chondrichthyans from FL 41 genera 52 13 Modified from Zachos et al. (2008) Taxonomic Diversity Functional Diversity Based on evolutionary relationships Based on ecological role Compagno (1990) Chondrichthyan Tree of Life Project Catshark Houndshark Bull Shark Tiger Shark Lemon Shark Sharpnose Shark Hammerhead Shark Bonnethead Shark 5 mm Sand Tiger Shark Mako Shark Great White Shark Basking Shark Thresher Shark 1 cm Cookiecutter Shark Cookiecutter Shark Nurse Shark Angel Shark Bullhead Shark Cow Shark 5 mm Bull Ray Cownose Ray Manta Ray Spotted Eagle Ray Whiptail Stingray Wedgefish Sawfish Guitarfish Functional Diversity: Dentition Types Cutting Grasping Crushing Clutching Filter-Feeding 5 mm 5 mm 10 mm Diet Diet Diet Diet Diet Medium to Small to Benthic hard- Benthic, small Microscopic large fleshy medium quick bodied prey soft-bodied prey prey prey Kent (1994) Functional Diversity: Ecomorphotype Ecomorphotype: Habitat Diet Locomotion Anatomy 21 types in the Florida fossil record Compagno (1990) Sampling Effort NALMA / Stage Age Range Time # of # of # of (Ma) Elapsed (Ma) Specimens Sites Formations Rancholabrean 0.012 – 0.25 0.238 779 52 2 Irvingtonian 0.25 – 1.6 1.35 1193 10 3 Blancan 1.6 – 4.75 3.15 1276 31 4 Hemphillian 4.75 – 9.0 4.25 88300 116 4 Clarendonian 9.0 – 12.5 3.5 10200 29 3 Barstovian 12.5 – 15.9 3.4 3438 16 3 Hemingfordian 15.9 – 18.9 3.0 1176 15 4 Arikareean 18.9 – 29.4 10.5 834 11 2 Whitneyan 29.4 – 31.4 2.0 23 1 0 Vicksburgian 31.4 – 33.9 2.5 266 2 2 Jacksonian 33.9 – 37.2 3.3 192 44 1 Claibornian 37.2 – 48.6 11.4 21 2 1 Ken Marks Results: Diversity Trends Taxonomic Diversity Functional Diversity Taxonomic Diversity 100% Discussion Hexanchiformes 80% Squatiniformes Taxonomic Diversity Orectolobiformes 60% Lamniformes Three dominant orders Carcharhiniformes 40% Rhinopristiformes Carcharhiniformes Rajiformes 20% Myliobatiformes Lamniformes Myliobatiformes 0% Shift from lamniform to carcharhiniform dominant fauna across the EOT Carcharhiniforms radiate during the Functional Diversity Miocene 100% Cutting Cutting-Grasping 80% Cutting-Crushing Functional Diversity Cutting-Clutching 60% Grasping Shift from grasping to cutting dominant Grasping-Cutting 40% Dietary preference towards larger prey Crushing Clutching 20% Small, benthic taxa poorly represented Clutching-Crushing Filter-Feeding 0% Eocene Lamniform Diversity of Alabama 10 genera (56% of the fauna) Two morphotypes: (1) Tall, narrow (=grasping) (2) Broadly triangular (=cutting) Cappetta and Case (2016) Lamniform to Carcharhiniform Transition in Maryland Purse State Park (Charles County) Bayfront Park (Calvert County) -Aquia Formation (~60 Ma) -Calvert Formation (~20 Ma) -Mostly grasping-type teeth -Mostly cutting-type teeth Discussion: Sampling Bias Haile Quarry Problems Solutions Preservation Focus efforts on screenwashing • Carbonate vs. Siliciclastic Collection Effort Increase awareness of gaps in the • Focus on the Neogene fossil record (e.g., Paleogene) Research Effort Promote use of myFOSSIL database • Focus on terrestrial vertebrates Temporal Resolution Site-based detailed descriptions • Tied to NALMA and regional lithology Strontium-dating tooth enameloid myFOSSIL Features Contribute to Research Conclusions There was a transition from a lamniform to carcharhiniform- dominant fauna across the EOT There was a long-term trend towards teeth with more efficient cutting adaptations, corresponding with a dietary shift towards larger prey Sampling bias is pervasive in the FLMNH collection, which should dictate future collection and research efforts Sharks! Sink your teeth in! What? New exhibit on sharks When? July 2021 – July 2022 Where? Mezzanine level at CMM.