Sharks and Rays of Florida: a 45-million-year history - Victor J. Perez Assistant Curator of Paleontology - Calvert Marine Museum
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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
Oldest Chondrichthyans from FL
77 taxa (original)
65 taxa (corrected)
10 orders
26 families
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 ProjectCatshark Houndshark
Bull Shark Tiger Shark
Lemon Shark
Sharpnose Shark
Hammerhead
Shark
Bonnethead
Shark
5 mmSand Tiger Shark
Mako Shark
Great White Shark
Basking Shark
Thresher Shark
1 cmCookiecutter Shark Cookiecutter Shark
Nurse Shark
Angel Shark
Bullhead Shark
Cow Shark
5 mmBull Ray Cownose Ray
Manta Ray
Spotted Eagle Ray
Whiptail Stingray
Wedgefish
Sawfish
GuitarfishFunctional 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 MarksResults: Diversity Trends Taxonomic Diversity Functional Diversity
Taxonomic Diversity
100% Discussion
Taxonomic Diversity
Hexanchiformes
80%
Squatiniformes
Orectolobiformes
Three dominant orders
60%
Lamniformes
Carcharhiniformes
Carcharhiniformes
40%
Rhinopristiformes
20%
Rajiformes
Myliobatiformes
Lamniformes
0%
Myliobatiformes
Shift from lamniform to carcharhiniform
dominant fauna across the EOT
Carcharhiniforms radiate during the
Functional Diversity Miocene
100%
Cutting
Functional Diversity
Cutting-Grasping
80%
Cutting-Crushing
Shift from grasping to cutting dominant
Cutting-Clutching
60%
Grasping
40%
Grasping-Cutting
Crushing
Dietary preference towards larger prey
20%
Clutching 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 teethDiscussion: 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 enameloidmyFOSSIL 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 CMMYou can also read
