DOCSLIB.ORG

Megalodon Reached a Maximum Body Length of 65 Ft!

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text

Load more

Megalodon Reached A Maximum Body Length Of 65 Ft! Posted by TBN(Staff) On 03/11/2021 SOLOMONS, Md. – Calvert Marine Museum’s Assistant Curator of Paleontology, Dr. Victor Perez, has just had a paper published in the journal Palaeontologia Electronica entitled: “Body length estimation of Neogene macrophagous lamniform sharks (Carcharodon and Otodus) derived from associated fossil dentitions.” This study was conducted at the Florida Museum on the University of Florida campus (Gainesville, FL) and was co-authored by Dr. Ronny Leder, Director of the Natural History Museum of Leipzig, and avocational paleontologist, Teddy Badaut. For more than 100 years, people have been debating the size of the extinct megatooth shark, Otodus megalodon. This macropredator has captivated the interest of researchers and the public alike, with its enormous, blade-like teeth. While it is often regarded as the largest shark to ever live, what evidence is available to substantiate this massive claim? To date, a complete skeleton of Otodus megalodon has not been recovered, so we cannot simply measure the length of the shark. The fossil record of megatooth sharks is predominantly comprised of isolated teeth and rare vertebral centra, which has been the basis for all previous methods for estimating body length. However, a recent study tested the accuracy of popular methods for estimating body length, using the most complete fossil evidence available—associated fossil dentitions (Figure 1). These are extremely rare sets of teeth that each came from one individual. The study found a distinct pattern, in which anterior teeth resulted in smaller body length estimates than posterior teeth, implying that previous studies that have analyzed body size trends in megatooth sharks are biased by which tooth positions were used in the analysis. Figure 1. The most complete known associated dentition of Megalodon, with common terminology used to describe the dentition. These teeth all originated from one shark! Scale bar = 5 cm. Figure modified from Perez et al. (2021). To account for this potential bias, a novel method for estimating body size was proposed, based on the summed width in associated fossil dentitions. In many living sharks, there is a precise relationship between the width of the jaws and the length of the shark. The new method assumes that the ratio of summed width to total body length (TL) is proportional in the living great white shark, Carcharodon carcharias, and the extinct megatooth shark, Otodus megalodon (Figure 2). Thus, there are four variables, of which three can be measured and the fourth can be calculated. This method provides significantly greater constraint on the resultant body length estimates than previous methods. Figure 2. Premise of the new method for estimating body length of the extinct megatooth shark. TL = Total body Length. Figure modified from Perez et al. (2021). The method was applied to 11 associated fossil dentitions, belonging to five different species: Otodus megalodon (extinct), Otodus chubutensis (extinct), Carcharodon hastalis (extinct), Carcharodon hubbelli (extinct), and Carcharodon carcharias (living). These five species were apex predators in shallow marine environments over the past 23 million years. To calculate a maximum body size, the method was extrapolated for the largest known isolated tooth of Otodus megalodon by relating it to the largest associated dentition (Figure 3). This resulted in a maximum body length estimate of 20 m (=65.6 ft). Figure 3. Maximum body length of Otodus megalodon, based on the largest known tooth. Note: the tooth enamel was repaired inside the red polygon. The slant height of the tooth is 7.25 inches (~184 mm). Scale bar = 5 cm. Otodus megalodon artwork by Tim Scheirer, with permission for use by the Calvert Marine Museum. Figure modified from Perez et al. (2021). Explore how the prehistoric past, natural environments, and maritime heritage come to life and tell a unique story of the Chesapeake Bay. The Calvert Marine Museum is open daily from 10 a.m. to 5 p.m., with limited capacity and a new timed entry system. Admission is $9 for adults; $7 for seniors, military with valid I.D, AAA and AARP members; $4 for children ages 5 - 12; children under 5 and museum members are admitted free. For more information about the museum, or to make a reservation for your next visit, please go to our website at www.calvertmarinemuseum.com. Keep up to date with the latest from CMM by following us on Facebook, Instagram, Twitter, and YouTube. Copyright © 2021 thebaynet.com. All rights reserved. Page 1.
Recommended publications
  • Vertebral Morphology, Dentition, Age, Growth, and Ecology of the Large Lamniform Shark Cardabiodon Ricki

    Vertebral Morphology, Dentition, Age, Growth, and Ecology of the Large Lamniform Shark Cardabiodon Ricki

    Vertebral morphology, dentition, age, growth, and ecology of the large lamniform shark Cardabiodon ricki MICHAEL G. NEWBREY, MIKAEL SIVERSSON, TODD D. COOK, ALLISON M. FOTHERINGHAM, and REBECCA L. SANCHEZ Newbrey, M.G., Siversson, M., Cook, T.D., Fotheringham, A.M., and Sanchez, R.L. 2015. Vertebral morphology, denti- tion, age, growth, and ecology of the large lamniform shark Cardabiodon ricki. Acta Palaeontologica Polonica 60 (4): 877–897. Cardabiodon ricki and Cardabiodon venator were large lamniform sharks with a patchy but global distribution in the Cenomanian and Turonian. Their teeth are generally rare and skeletal elements are less common. The centra of Cardabiodon ricki can be distinguished from those of other lamniforms by their unique combination of characteristics: medium length, round articulating outline with a very thick corpus calcareum, a corpus calcareum with a laterally flat rim, robust radial lamellae, thick radial lamellae that occur in low density, concentric lamellae absent, small circular or subovate pores concentrated next to each corpus calcareum, and papillose circular ridges on the surface of the corpus calcareum. The large diameter and robustness of the centra of two examined specimens suggest that Cardabiodon was large, had a rigid vertebral column, and was a fast swimmer. The sectioned corpora calcarea show both individuals deposited 13 bands (assumed to represent annual increments) after the birth ring. The identification of the birth ring is supported in the holotype of Cardabiodon ricki as the back-calculated tooth size at age 0 is nearly equal to the size of the smallest known isolated tooth of this species. The birth ring size (5–6.6 mm radial distance [RD]) overlaps with that of Archaeolamna kopingensis (5.4 mm RD) and the range of variation of Cretoxyrhina mantelli (6–11.6 mm RD) from the Smoky Hill Chalk, Niobrara Formation.
  • Evolution of White and Megatooth Sharks, and Evidence for Early Predation on Seals, Sirenians, and Whales

    Evolution of White and Megatooth Sharks, and Evidence for Early Predation on Seals, Sirenians, and Whales

    Vol.5, No.11, 1203-1218 (2013) Natural Science http://dx.doi.org/10.4236/ns.2013.511148 Evolution of white and megatooth sharks, and evidence for early predation on seals, sirenians, and whales Cajus G. Diedrich Paleologic, Petra Bezruce 96, Zdice, Czech Republic; [email protected], www.paleologic.eu Received 6 April 2013; revised 6 May 2013; accepted 13 May 2013 Copyright © 2013 Cajus G. Diedrich. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. ABSTRACT ments were generally first attributed to “white shark Carcharodon carcharias (Linné, 1758) ancestors”. Con- The early white shark Carcharodon Smith, 1838 troversy has subsequently arisen whether they should be with the fossil Carcharodon auriculatus (Blain- ascribed to the megatooth shark (“Carcharocles”—he- ville, 1818) and the extinct megatooth shark Oto- rein Otodus), or to the white shark (Carcharodon) line- dus Agassiz, 1843 with species Otodus sokolovi age [1]. This controversy is partly a result of non-sys- (Jaeckel, 1895) were both present in the Euro- tematic excavation of single serrated similar looking pean proto North Sea Basin about 47.8 - 41.3 m.y. teeth from many localities around the world, and from ago (Lutetian, early Middle Eocene), as well as in horizons of different ages. DNA studies have at least the Tethys realm around the Afican-Eurasian resolved the general position of the extant form of Car- shallow marine habitats. Both top predators deve- charodon carcharias, placing it between the Isurus and loped to be polyphyletic, with possible two dif- Lamna genera [2,3], without taking into account a revi- ferent lamnid shark ancestors within the Early sion and including of extinct fossil species such as Oto- Paleocene to Early Eocene timespan with Car- dus.
  • First Description of a Tooth of the Extinct Giant Shark Carcharocles

    First Description of a Tooth of the Extinct Giant Shark Carcharocles

    First description of a tooth of the extinct giant shark Carcharocles megalodon (Agassiz, 1835) found in the province of Seville (SW Iberian Peninsula) (Otodontidae) Primera descripción de un diente del extinto tiburón gigante Carcharocles megalodon (Agassiz, 1835) encontrado en la provincia de Sevilla (SO de la Península Ibérica) (Otodontidae) José Luis Medina-Gavilán 1, Antonio Toscano 2, Fernando Muñiz 3, Francisco Javier Delgado 4 1. Sociedad de Estudios Ambientales (SOCEAMB) − Perú 4, 41100 Coria del Río, Sevilla (Spain) − [email protected] 2. Departamento de Geodinámica y Paleontología, Facultad de Ciencias Experimentales, Universidad de Huelva − Campus El Carmen, 21071 Huelva (Spain) − [email protected] 3. Departamento de Geodinámica y Paleontología, Facultad de Ciencias Experimentales, Universidad de Huelva − Campus El Carmen, 21071 Huelva (Spain) − [email protected] 4. Usuario de BiodiversidadVirtual.org − Álvarez Quintero 13, 41220 Burguillos, Sevilla (Spain) − [email protected] ABSTRACT: Fossil remains of the extinct giant shark Carcharocles megalodon (Agassiz, 1835) are rare in interior Andalusia (Southern Spain). For the first time, a fossil tooth belonging to this paleospecies is described from material found in the province of Seville (Burguillos). KEY WORDS: Carcharocles megalodon (Agassiz, 1835), megalodon, Otodontidae, fossil, paleontology, Burguillos, Seville, Tortonian. RESUMEN: Los restos del extinto tiburón gigante Carcharocles megalodon (Agassiz, 1835) son raros en el interior de Andalucía (sur de España). Por primera vez, se describe un diente fósil de esta paleoespecie a partir de material hallado en Sevilla (Burguillos). PALABRAS CLAVE: Carcharocles megalodon (Agassiz, 1835), megalodón, Otodontidae, fósil, paleontología, Burguillos, Sevilla, Tortoniense. Introduction Carcharocles megalodon (Agassiz, 1835), the megalodon, is widely recognised as the largest shark that ever lived.
  • New Chondrichthyans from Bartonian-Priabonian Levels of Río De Las Minas and Sierra Dorotea, Magallanes Basin, Chilean Patagonia

    New Chondrichthyans from Bartonian-Priabonian Levels of Río De Las Minas and Sierra Dorotea, Magallanes Basin, Chilean Patagonia

    Andean Geology 42 (2): 268-283. May, 2015 Andean Geology doi: 10.5027/andgeoV42n2-a06 www.andeangeology.cl PALEONTOLOGICAL NOTE New chondrichthyans from Bartonian-Priabonian levels of Río de Las Minas and Sierra Dorotea, Magallanes Basin, Chilean Patagonia *Rodrigo A. Otero1, Sergio Soto-Acuña1, 2 1 Red Paleontológica Universidad de Chile, Laboratorio de Ontogenia y Filogenia, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Las Palmeras 3425, Santiago, Chile. [email protected] 2 Área de Paleontología, Museo Nacional de Historia Natural, Casilla 787, Santiago, Chile. [email protected] * Corresponding author: [email protected] ABSTRACT. Here we studied new fossil chondrichthyans from two localities, Río de Las Minas, and Sierra Dorotea, both in the Magallanes Region, southernmost Chile. In Río de Las Minas, the upper section of the Priabonian Loreto Formation have yielded material referable to the taxa Megascyliorhinus sp., Pristiophorus sp., Rhinoptera sp., and Callorhinchus sp. In Sierra Dorotea, middle-to-late Eocene levels of the Río Turbio Formation have provided teeth referable to the taxa Striatolamia macrota (Agassiz), Palaeohypotodus rutoti (Winkler), Squalus aff. weltoni Long, Carcharias sp., Paraorthacodus sp., Rhinoptera sp., and indeterminate Myliobatids. These new records show the presence of common chondrichtyan diversity along most of the Magallanes Basin. The new record of Paraorthacodus sp. and P. rutoti, support the extension of their respective biochrons in the Magallanes Basin and likely in the southeastern Pacific. Keywords: Cartilaginous fishes, Weddellian Province, Southernmost Chile. RESUMEN. Nuevos condrictios de niveles Bartoniano-priabonianos de Río de Las Minas y Sierra Dorotea, Cuenca de Magallanes, Patagonia Chilena. Se estudiaron nuevos condrictios fósiles provenientes de dos localidades, Río de Las Minas y Sierra Dorotea, ambas en la Región de Magallanes, sur de Chile.
  • Body Length Estimation of Neogene Macrophagous Lamniform Sharks (Carcharodon and Otodus) Derived from Associated Fossil Dentitions

    Body Length Estimation of Neogene Macrophagous Lamniform Sharks (Carcharodon and Otodus) Derived from Associated Fossil Dentitions

    Palaeontologia Electronica palaeo-electronica.org Body length estimation of Neogene macrophagous lamniform sharks (Carcharodon and Otodus) derived from associated fossil dentitions Victor J. Perez, Ronny M. Leder, and Teddy Badaut ABSTRACT The megatooth shark, Otodus megalodon, is widely accepted as the largest mac- rophagous shark that ever lived; and yet, despite over a century of research, its size is still debated. The great white shark, Carcharodon carcharias, is regarded as the best living ecological analog to the extinct megatooth shark and has been the basis for all body length estimates to date. The most widely accepted and applied method for esti- mating body size of O. megalodon was based upon a linear relationship between tooth crown height and total body length in C. carcharias. However, when applying this method to an associated dentition of O. megalodon (UF-VP-311000), the estimates for this single individual ranged from 11.4 to 41.1 m. These widely variable estimates showed a distinct pattern, in which anterior teeth resulted in lower estimates than pos- terior teeth. Consequently, previous paleoecological analyses based on body size esti- mates of O. megalodon may be subject to misinterpretation. Herein, we describe a novel method based on the summed crown width of associated fossil dentitions, which mitigates the variability associated with different tooth positions. The method assumes direct proportionality between the ratio of summed crown width to body length in eco- logically and taxonomically related fossil and modern species. Total body lengths were estimated from 11 individuals, representing five lamniform species: Otodus megal- odon, Otodus chubutensis, Carcharodon carcharias, Carcharodon hubbelli, and Carcharodon hastalis.
  • Paleogene: Paleocene) Of

    Paleogene: Paleocene) Of

    Cainozoic Research, 8(1-2), pp. 13-28, December2011 Chondrichthyans from the Clayton Limestone Unit of the Midway Group (Paleogene: Paleocene) of Hot Spring County, Arkansas, USA ¹, ² Martin+A. Becker Lauren+C. Smith¹ & John+A. Chamberlain+Jr. 1 Department ofEnvironmentalScience, William Paterson University, Wayne, New Jersey 07470; e-mail: [email protected] 2 Department ofGeology, Brooklyn College andDoctoralProgram in Earth and EnvironmentalSciences, City University ofNew YorkGraduate Center, New York 10016; email:[email protected] Received 7 September 2010; revised version accepted 26 June 2011 LimestoneUnit of The Clayton the Midway Group (Paleocene) in southwestern Arkansas preserves one ofthe oldest chondrichthyan Cenozoic from the Gulf Coastal Plainofthe United assemblages yet reported States. Present are at least eight taxa, including; Odontaspis winkleriLeriche, Carcharias cf. whitei Carcharias Anomotodon 1905; (Arambourg, 1952); sp.; novus (Winkler, 1874); Cretalamnasp.; Otodus obliquus Agassiz, 1843; Hypolophodon sylvestris (White, 1931); Myliobatis dixoni Agassiz, 1843; and a chimaeridofindeterminate affiliation.Also present are lamnoid-type and carcharhinoid-type chondrichthyan vertebral centra. The Clayton chondrichthyan assem- blage derives from an outcrop locatedonly a few kilometersfrom a site exposing an assemblage ofMaastrichtianchondrichthyans from Because and the upper Arkadelphia Marl. these assemblages are closely spaced stratigraphically geographically, they provide data on chondrichthyan taxonomic turnover
  • Nursery in the Oligocene Charleston Embayment, South Carolina, USA

    Nursery in the Oligocene Charleston Embayment, South Carolina, USA

    Palaeontologia Electronica palaeo-electronica.org A megatoothed shark (Carcharocles angustidens) nursery in the Oligocene Charleston Embayment, South Carolina, USA Addison E. Miller, Matthew L. Gibson, and Robert W. Boessenecker ABSTRACT Many extant sharks are cosmopolitan as adults but inhabit nursery areas as youngsters - often shallow, dynamic ecosystems with abundant prey for neonates and juveniles. Megatoothed sharks (Otodontidae) were the largest sharks of all time, and nursery areas have been demonstrated for Carcharocles megalodon in the Miocene of Panama, Spain, Florida, and Maryland. An earlier study hypothesized a nursery area for Carcharocles angustidens in the upper Oligocene (23-25 Ma) Chandler Bridge For- mation of Charleston, South Carolina. We tested this by reporting and analyzing two collections (n=127) dominated by small teeth of C. angustidens from the Chandler Bridge Formation and some teeth from the underlying lower Oligocene (29-26.57 Ma) Ashley Formation (n=9). Correcting for tooth position, published body length estimation equations yielded body length estimates of 1.5-6.5 m for most individuals. Size-based assignment to age classes (neonates, juveniles, adults) is modified from the larger C. megalodon and scaled based on the largest available specimens of C. angustidens, reported herein. These assemblages are dominated by small individuals (juveniles and neonates) and include few adults. The Oligocene Charleston embayment therefore represents the first documented paleo-nursery area for C. angustidens. Addison Miller. Department of Geology and Environmental Geosciences, College of Charleston, Charleston, South Carolina 29424, USA. [email protected] Matthew Gibson. Charleston Museum, Charleston, South Carolina 29403, USA. [email protected] Robert Boessenecker, Mace Brown Museum of Natural History and Department of Geology and Environmental Geosciences, College of Charleston, Charleston, South Carolina 29424, USA.
  • Contributions from the Museum of Paleontology, University of Michigan

    Contributions from the Museum of Paleontology, University of Michigan

    Contributions from the Museum of Paleontology, University of Michigan VOL. 32, NO. 6, PP. 71-90 APRIL 30, 2012 PRIABONIAN SHARKS AND RAYS (LATE EOCENE: NEOSELACHII) FROM MINQAR TABAGHBAGH IN THE WESTERN QATTARA DEPRESSION, EGYPT BY IYAD S. A. ZALMOUT1, MOHAMMAD S. M. ANTAR2,3, EZZAT ABD-EL SHAFY2, MAMOUD H. METWALLY2, EL-BIALY E. HATAB4, AND PHILIP D. GINGERICH1 Abstract — A Priabonian (late Eocene) neoselachian fauna of sharks and rays is known from marine strata in the foothills of Minqar Tabaghbagh, near the southwestern corner of the Qattara Depression in the Western Desert of Egypt. Neoselachian remains were collected from the lower glauconitic shales and mudstones of the Daba’a Formation, which is a western equivalent of the Qasr El-Sagha Formation found in the eastern part of the Western Desert. Neoselachians studied here are macro-scale, collected on the surface, and known either from teeth or rostral remains. Taxonomic evaluation shows that the neoselachians belong to five orders, 11 families, 19 genera, and 24 species. The species are:Hexanchus agassizi, Carcharias sp., Otodus cf. O. sokolowi, Brachycarcharias cf. B. twiggsensis, Macrorhizodus praecursor, Xiphodolamia serrata, Alopias alabamensis, Alopias sp., Abdounia aff. A. minutissima, Misrichthys stromeri, Carcharhinus sp. 1, Carcharhinus sp. 2, Galeocerdo sp. 1, Galeocerdo sp. 2, Negaprion frequens, Negaprion sp., Physogalus sp., Rhizoprionodon sp., Anoxypristis sp., Propristis schweinfurthi, Pristis lathami, Myliobatis sp. 1, Myliobatis sp. 2, and an indeterminate sting ray spine. Teeth of Otodus cf. O. sokolowi and Macrorhizodus praecursor are the most abundant remains recovered from the locality. Recovery of Xiphodolamia serrata confirms the late Eocene age of the faunal Minqar Tabaghbagh assemblage.
  • Vol 35, Number 4, December 2020

    Vol 35, Number 4, December 2020

    The ECPHORA The Newsletter of the Calvert Marine Museum Fossil Club Volume 35 Number 4 December 2020 Features Up and Coming Artist Art by Eaton Ekarintaragun Shark Dentitions by George F. Klein Pathologic Shark Teeth by Bill Heim Inside President’s Column Membership Renewal Polymer Ammonite Ecphoras Found Pathological Otodus Tooth Fossil Carcharodon carcharias Tooth Found Special Needs Night Self-Bitten Snaggletooth Bohaska on the Beach Seahorse Skeleton and CMMFC young member, Eaton Ekarintaragun loves both paleontology much more… and art. Here is an example of one of his recent pieces. This is Eaton's CMM Fossil Club interpretation/creation of a Synthetoceras. Meetings. Note the new day of the week, date, and time for our next fossil club meeting. Monday, February 22, 2021, 7 pm, Zoom meeting. Public lecture by Dr. Victor Perez to begin at 7:30 pm. Zoom invitation to follow via email. Work in progress. Photos submitted by Pitoon Ekarintaragun. ☼ CALVERT MARINE MUSEUM www.calvertmarinemuseum.com 2 The Ecphora December 2020 Greetings Club Members! Sculpey Polymer Clay Ammonite President’s Column. Every time it seems it can’t get worse 2020 dishes out something new. As I write this my neighbor was just taken away via ambulance, the remote server for my workplace crashed and the water main for our street ruptured. All of this within 2 hours on a Monday afternoon. Ugh. I hope everyone is coping as best as possible during this crazy year and is relaxing whenever possible outdoors, be it just taking a walk or getting in a fossil excursion. Keeping stress-free seems to be the best medicine lately.
  • Bulletin 4, a Description of the Fossil Fish Remains of the Cretaceous, Eocene and Miocene Formations

    Bulletin 4, a Description of the Fossil Fish Remains of the Cretaceous, Eocene and Miocene Formations

    OEOLOGICAL SURVEY OF NEW JERSEY HENRY B. K{JMM_L. STAT_ GEOLOGIST BULLETIN4. A Descriptionof the Fossil Fish.Remains OF THE Cretaceous, Eocene and Miocene Formations of New Jersey By HENRY W. FOWLER of the Academy of Natural Sciences of Philadelphia With a Chapter on the Oeology by HENRY B. KOMMEL TRENTON, N. J. Ma¢Crellish & Quigtey, State Printevs, Opposite Post Office. 1911. NEW JERSEY GEOLOGICAL SURVEY Letter of Transmittal. TR_N'rO_, N. J., MARc_ _7, _9 :_I. The State Printing Board, Trenton., N. J. G_NTLE_EN--Chapter 46, Laws of 19I% provides that. in addition to an annual administrative report, the State Geologist shall prepare or cause robe prepared such scientific reports as are pertinent to the work of his department, and that the State Printing Board shall have authorityi on recommendation of the Board of Managers of the Survey, to order printed such seien- title reports. The Board of l_fanagers of the Survey, on December 6, t9Io, adopted the following mo_ion: That the publication of reports on the Plant Remains of the Cretaeeons Clay Beds, and on the Fossil Fishes of the Cretaceous and Miocene Formations of South Jersey, alrehdy prepared or in process of preparation under the direction of the State Geologist, be recommended for printing to the State Printing Board, as provided in Chapter 46, Laws of IgIo. In accordance with the above, I request that the State Printing Board order printed t,5oo copies each of the two reports above mentioned, Ioo to be bound, the balance in stiff covers sewed, as provided in the specifications for printing the Geological Sur- vey reports.
  • Occurrence of the Megatoothed Sharks (Lamniformes: Otodontidae) in Alabama, USA

    Occurrence of the Megatoothed Sharks (Lamniformes: Otodontidae) in Alabama, USA

    A peer-reviewed version of this preprint was published in PeerJ on 14 October 2014. View the peer-reviewed version (peerj.com/articles/625), which is the preferred citable publication unless you specifically need to cite this preprint. Ehret DJ, Ebersole J. 2014. Occurrence of the megatoothed sharks (Lamniformes: Otodontidae) in Alabama, USA. PeerJ 2:e625 https://doi.org/10.7717/peerj.625 Occurrence of the Megatoothed sharks (Lamniformes:Otodontidae) in Alabama, USA The Otodontidae include some of the largest sharks to ever live in the world’s oceans (i.e. Carcharocles megalodon). Here we report on Paleocene and Eocene occurrences of Otodus obliquus and Carcharocles auriculatus from Alabama, USA. Teeth of Otodus are rarely encountered in the Gulf Coastal Plain and this report is one of the first records for Alabama. Carcharocles auriculatus is more common in the Eocene deposits of Alabama, but its occurrence has been largely overlooked in the literature. We also refute the occurrence of the Oligocene Carcharocles angustidens in the state. Raised awareness and PrePrints increased collecting of under-sampled geologic formations in Alabama will likely increase sample sizes of O. obliquus and C. auriculatus and also might unearth other otodontids, such as C. megalodon and C. chubutensis. PeerJ PrePrints | http://dx.doi.org/10.7287/peerj.preprints.517v1 | CC-BY 4.0 Open Access | rec: 29 Sep 2014, publ: 29 Sep 2014 1 Occurrence of the Megatoothed sharks (Lamniformes:Otodontidae) in Alabama, USA 2 Authors: Ehret, Dana J.1 and Ebersole, Jun2 3 1Alabama Museum of Natural History, PO Box 870340, Tuscaloosa, Alabama 35487-0340 4 Email: [email protected] 5 2McWane Science Center, 200 19th Street North, Birmingham, Alabama 35203 6 Email: [email protected] 7 Corresponding Author: Ehret, Dana J.
  • Body Dimensions of the Extinct Giant Shark Otodus Megalodon: a 2D Reconstruction Jack A

    Body Dimensions of the Extinct Giant Shark Otodus Megalodon: a 2D Reconstruction Jack A

    www.nature.com/scientificreports OPEN Body dimensions of the extinct giant shark Otodus megalodon: a 2D reconstruction Jack A. Cooper1, Catalina Pimiento2,3,4*, Humberto G. Ferrón1 & Michael J. Benton1 Inferring the size of extinct animals is fraught with danger, especially when they were much larger than their modern relatives. Such extrapolations are particularly risky when allometry is present. The extinct giant shark †Otodus megalodon is known almost exclusively from fossilised teeth. Estimates of †O. megalodon body size have been made from its teeth, using the great white shark (Carcharodon carcharias) as the only modern analogue. This can be problematic as the two species likely belong to diferent families, and the position of the †Otodus lineage within Lamniformes is unclear. Here, we infer †O. megalodon body dimensions based on anatomical measurements of fve ecologically and physiologically similar extant lamniforms: Carcharodon carcharias, Isurus oxyrinchus, Isurus paucus, Lamna ditropis and Lamna nasus. We frst assessed for allometry in all analogues using linear regressions and geometric morphometric analyses. Finding no evidence of allometry, we made morphological extrapolations to infer body dimensions of †O. megalodon at diferent sizes. Our results suggest that a 16 m †O. megalodon likely had a head ~ 4.65 m long, a dorsal fn ~ 1.62 m tall and a tail ~ 3.85 m high. Morphometric analyses further suggest that its dorsal and caudal fns were adapted for swift predatory locomotion and long-swimming periods. Estimating the body size of exceptionally large extinct taxa is a difcult task because the fossil record is inherently incomplete and because allometry, if present, can make extrapolations hard to model.