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Discovery of a Pleistocene mysticete whale, Georgia Bight (USA)

Ervan G. Garrison, Greg McFall, Alexander Cherkinsky, and Scott E. Noakes

Plain Language Abstract

During the fall of 2006, scientific divers from The University of Georgia (UGA) and the National Oceanic and Atmospheric Administration (NOAA) were conducting a reconnaissance dive at JY reef approximately 20 nautical miles offshore Georgia. During this dive, a large fossilized bone was discovered partially embedded in the reef. On subsequent dives, loose sand was removed from around the bone and a small section was recovered (see video in Appendix). This bone fragment was radiocarbon dated to approximately 36,000 years before present (byp). However, since the bone was determined to be much larger than originally thought, it would require extensive excavation, thus a bottom disturbing permit was required. After approximately one year of discussions with multiple state and federal agencies, the United States Army Corps of Engineers issued a permit for excavation. Excavation began in the summer of 2008 and involved cutting through fossilized shell beds before reaching softer, but hard packed silt that encased the large bone. Divers worked diligently with hammers, chisels and knives to cut away the overburden and carefully remove the sediment immediately around the bone. After numerous dives, the bone was recovered in sections totaling approximately 1.5 m in length. The bone has been preliminarily identified as an Atlantic gray whale mandible. Subsequent work included stabilization, restoration and comparative paleontological study to verify our preliminary taxonomic identification. A joint UGA and Emory University team professionally restored the bone for study and display. The results of these studies are reported in this paper.

Resumen en Español

Hallazgo de un cetáceo misticeto del Pleistoceno en el golfo de Georgia (EE. UU.)

En este artículo se da cuenta del hallazgo de restos subósiles de un cetáceo misticeto en un yacimiento submarino situado en el golfo de Georgia, a unos 30 km mar adentro de la isla de St. Catherines. Los restos incluyen un dentario casi completo (~77 %) (mandíbula izquierda) y dos vértebras fuertemente erosionadas. El descubrimiento inicial de la mandíbula tuvo lugar en 2006, pero la excavación no se completó hasta el verano de 2008. Las dos vértebras, mal preservadas, fueron halladas cerca del mismo afloramiento, del cual habían sido exhumadas por la erosión. Las dos vértebras fueron datadas pero no han sido analizadas en este trabajo. La datación por radiocarbono de los subfósiles, llevada a cabo mediante espectrometría de acelerador de partículas (AMS) utilizando bioapatito en lugar de colágeno, sugiere una edad común para los restos esqueléticos de entre 34000 y 37000 años, aunque no es segura la pertenencia de todos los restos a un mismo individuo o, ni siquiera, a un mismo taxón. La edad calculada para los subfósiles concuerda con la edad del sedimento, una lumaquela de conchas, previamente determinada por la datación mediante AMS de inclusiones y por la datación directa de los sedimentos mediante luminiscencia estimulada ópticamente (OSL). Además, también se obtuvieron edades para la lumaquela mediante racemización de aminoácidos (AAR). El análisis comparativo de los caracteres morfológicos preservados del dentario recolectado con los de mandíbulas de misticetos sugiere afinidades con los Balaenopteridae o los Eschrichtiidae. Junto con el reciente hallazgo de materiales pleistocenos en el Mar del Norte (Europa), los nuevos restos bien datados de Norteamérica podrían aportar nuevas pruebas de la desaparición de la ballena gris en el Atlántico durante el Cuaternario.

Palabras clave: Ballena; Misticeto; Pleistoceno; golfo de Georgia

Traducción: Miguel Company

Résumé en Français

Découverte d'une baleine mysticète Pléistocène, baie de Georgia (USA)

Des preuves subfossiles, incluant une mandibule gauche presque complète (~77 %) et deux vertèbres fortement érodées, d'une baleine mysticète, ont été découverts, sous l'eau, in situ, dans le baie de Georgia, à 30 kms des côtes de l'île St. Catherine, Georgia. La découverte de la mandibule fut faite initialement en 2006 mais l'extraction n'a été finie qu'à l'été 2008. Deux vertèbres on été retrouvées à proximité, ayant été érodées à partir du même affleurement que la mandibule. Les deux vertèbres ont été datées mais ne sont pas analysées dans le présent compte rendu. Une datation directe des subfossiles, avec la technique de datation radiocarbone par spectromètre de masse par accélération (AMS), utilisant la bioapatite, plutôt que le collagène, suggèrent un âge commun pour ces éléments de squelette, compris entre 34.000 to 37.000 ka, mais l'attribution de ces restes à un même individu, ou même, à un même taxa, reste pour spéculative. Les âges déterminés pour ces subfossiles sont en accord avec l'âge de dépôts géologiques, et avec l'âge d'une coquille de coquina précédemment déterminé par datation AMS des inclusions, et la datation directe des sédiments utilisant la luminescence optiquement stimulée (OSL). En complément, un âge a été obtenu pour la coquille par racemisation des acides aminés (AAR). Nos analyses comparatives supportent la diagnose d'une mandibule de baleine mysticète. Des comparaisons supplémentaires des caractères morphologiques préservés avec ceux des mandibules de mysticètes supportent une diagnose plus poussée en tant que balaenopteridé ou eschrichtiidé. Associée aux récentes découvertes d'âge pléistocènes en Europe dans le bassin de la Mer du Nord, ces restes pourraient fournir une nouvelle preuve bien datée de l'extirpation de la baleine grise dans le bassin Atlantique au Quaternaire.

Mots clés : baleine, Pléistocène, baie de Georgia

Translator: Olivier Maridet

Deutsche Zusammenfassung

Fund eines Bartenwals aus dem Pleistozän von Georgia Bight (USA)

In der Georgia Bight, 30 km von der Küste von St. Catherine's Island in Georgia wurde unter Wasser in Situ ein subfossiler Nachweis mit einem nahezu kompletten linken Unterkiefer ( ~77 %) und zwei stark erodierten Wirbeln eines Bartenwals entdeckt. Ursprünglich wurde der Unterkiefer bereits 2006 entdeckt, jedoch waren die Ausgrabungen erst im Sommer 2008 beendet. Zwei schlecht erhaltene Wirbel, die aus derselben Fundstelle wie das Dentale herausgewittert waren, wurden in der Nähe gefunden. Sie wurden datiert, werden jedoch in diesem Report nicht analysiert. Eine direkte Datierung der Subfossilien mit Beschleunigungs-Massenspektrometrie – Radiokarbonverfahren (AMS) mit Bioapatit anstatt Kollagen ergab eine Altersspanne von 34 000 bis 37 000 Jahre. Jedoch ist es spekulativ die Reste einem Tier oder damit einem Taxon zuzuschreiben. Das ermittelte Alter stimmt gut mit dem Alter der geologischen Ablagerungen überein. Diese Coquina Lage wurde erst kürzlich mit AMS Datierung von Einschlüssen und direkter Datierung von Sedimenten mit der Optisch Stimulierten Lumineszenz (OSL) datiert. Zusätzlich wurden für die Coqunia Aminosäure Racemisierungsalter (AAR) erzielt. Unsere vergleichende Analyse unterstützt die Diagnose für ein Dentale eines Bartenwals. Weitere Vergleiche der erhaltenen morphologischen Merkmale mit denen von Unterkiefern von Bartenwalen erlauben eine weitere Zuordnung zu den Balaenopteriden oder Eschrichtiiden. Zusammen mit anderen pleistozänen Funden in Europa und im Nordseebecken können diese Funde einen neuen gut datierten Nachweis für den ausgerotteten Grauwal im quartären atlantischen Becken darstellen.

SCHLÜSSELWÖRTER: Wal; Mysticeti; Pleistozän; Georgia BightIn progress

Translators: Eva Gebauer

Arabic

323 arab

Translator: Ashraf M.T. Elewa

 

 

 

Video, “Prehistoric Baleen Whale Bone Excavation, J-Reef, Georgia Bight, 29 July 2008.” Created by James L. Demmers, Georgia Institute of Technology, Atlanta, GA. Click on image to see video.

appendix

 

 

TABLE 1. Radiometric ages for sub-fossil elements using AMS-radiocarbon method

UGA# Sample ID Bone type Bioapatite Collagen-like organics
δ13C 14C age, years BP δ13C 14C age, years BP
4024 GMNH-27370 vertebra -7.66 37,580±120 -20.96 10,630±40
4281 GMNH-27372 mandible -6.62 36,570±300 -20.25 10,350±80
4215 GMNH-27373 vertebra -6.67 34,520±160 -21.21 8,080±40

 

TABLE 2. Eschrichtius robustus, holotype. Dentary measurements (in mm).

Specimen Number GMNH-27372
Length (straight) 137 cm
Length (chord) 142 cm
Height at mandibular foramen 170mm
Height at condyle (inferred) 190 mm (160 actual)
Height at coronoid process (inferred) 130 actual (broken)
Minimum height between condyle and coronoid process 170 mm
Circumference 100 mm behind proximal end 360 mm
Circumference 200 mm behind proximal end 470 mm
Circumference 300 mm behind proximal end 410 mm
Circumference 400 mm behind proximal end 460 mm
Circumference 500 mm behind proximal end 490 mm
Circumference 600 mm behind proximal end 492 mm
Circumference 700 mm behind proximal end 492 mm
Circumference 800 mm behind proximal end 492 mm
Circumference 900 mm behind proximal end 490 mm
Circumference 1000 mm behind proximal end 490 mm
Distance between condyle and coronoid process 300 mm (inferred)
Distance between coronoid process and anterior end 360 (inferred)
 

FIGURE 1. Location map for J Reef locality in the Georgia Bight, Atlantic Ocean.

figure 1 

FIGURE 2. Generalized geologic section for coastal Georgia based on Weems and Edwards (2001). The inset corresponds to the upper portion of the general geologic section. The relative position for the mandible is marked.

 figure 2

FIGURE 3. Comparative views – dentary : 3.1. Two views, medially, of the mandibular neck; 3.2. Two views, proximally, of the condylar region, Mysticete (left); Megaptera novaeangliae (right).

 figure 3

FIGURE 4. 4.1. Dentary of Eschrichtius robustus, from Johnston et al., 2010, figure 2, p. 189 (above); 4.2. Mysticete dentary (proximal view) compared to that of Megaptera novaeangliae (distal view).

figure 4

 

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author1Department of Geology
Department of Anthropology
University of Georgia
Athens, GA 30602
USA

Ervan Garrison is a Professor of Geology & Anthropology at the University of Georgia. He is
a specialist in geoarchaeology. He has worked on the continental shelves of the U.S. Atlantic
and Pacific Coasts since 1990 conducting archaeological and paleontological studies. He is a scientific diver with over 700 research-related dives. He received his Ph.D. in 1979 from the University of Missouri. He has been at the University of Georgia since 1992.

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author2Gray's Reef National Marine Sanctuary
National Oceanic and Atmospheric Administration (NOAA)
20 Ocean Science Circle
Savannah, GA 31411
USA

Greg currently works as the Deputy Sanctuary Superintendent and Research Coordinator for Gray's Reef National Marine Sanctuary in Savannah, Georgia, where he coordinates scientific investigations into the ecology and oceanography of hard-bottom reefs. He worked for seven years with Dr. Joe Pawlik in the Chemical Ecology Laboratory of the University of North Carolina at Wilmington where he studied the ecology of tropical sponges. He served as the Assistant Science Director for UNCW's National Undersea Research Center for a year after receiving a M.S. degree from UNCW's Marine Biology program.
Prior to graduate work, he obtained a B.S. degree in Biology from West Virginia University. Greg spent five years as a commercial diver before attending college and was trained as a US Navy Diver while serving in the military. He grew up in Little Rock, Arkansas, and graduated High School in Duncanville, Texas, and always enjoyed spending lots of time in and around the water.

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author3Senior Research Scientist
Center for Applied Isotope Studies (CAIS)
The University of Georgia
Athens, Georgia 30602
USA

Alex Cherkinsky, Ph.D., is a Senior Research Scientist and Biogeochemist at the Center for Applied Isotope Studies (CAIS) at the University of Georgia. His research interests include the applications of AMS to archaeology, geology, hydrology and the environmental sciences.
Alex has interests in the development of new techniques for AMS sample preparation, measurement and data analysis and has developed novel approaches for radiocarbon dating of ultra-small samples. He has long-term interests in soil chemistry and soil carbon, and his research on the radiocarbon dating of soil is internationally recognized.

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author4Senior Research Scientist
Center for Applied Isotope Studies (CAIS)
The University of Georgia
Athens, Georgia 30602
USA

Scott Noakes, Ph.D., is a marine scientist and geochemist with research interests primarily focused on the development of sensors for real-time in situ measurements of the marine environment. His work with sensors has extended into methane gas hydrate detection and carbon dioxide monitoring in the ocean, and he has worked to develop a system that can be used to map hydrate deposits in the deep water of the Gulf of Mexico. Scott also has led a marine paleontological research project producing evidence of two extinct Atlantic gray whales of Pleistocene age in coastal Georgia waters. He presently serves as Director of the Scientific Diving Program for the University System of Georgia. His current research interests include ocean acidification and its detection and measurement using surface and near-surface sensors.

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