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Deciduous dentition and dental eruption sequence of Bothriogenys fraasi (Anthracotheriidae, Artiodactyla)
from the Fayum Depression, Egypt

Hesham M. Sallam, Afifi H. Sileem, Ellen R. Miller, and Gregg F. Gunnell

Plain Language Abstract

Anthracotheres ("coal beasts") are an extinct group of artiodactyls that thrived across the northern continents and Africa from 38 to 18 million years ago. They ranged in size from that of a small deer to larger than a hippopotamus. Most anthracotheres lived near rivers and ponds, ate aquatic and semi-aquatic vegetation and many were partially aquatic in a manner similar to living hippos. Even though they were hippo-like in habit it is not clear which other artiodactyl group anthracotheres may have been related to with both hippos and pigs having been previously favored as potential relatives. Anthracotheres are especially abundant from 30 million year old rocks in the Fayum Depression in the Western Desert of Egypt represented by a species called Bothriogenys fraasi. The Fayum B. fraasi sample includes many virtually complete jaws that span every age class from new born to mature adult. This permits documentation of the dental eruption pattern and the stages of tooth development for the species. It is clear from the study presented here that the dental eruption pattern of Bothriogenys fraasi is unlike that seen in hippos and more like that seen in pigs. However, this may simply reflect different life history patterns for anthracotheres and pigs compared to hippos whose life span is three to four times longer than those of the former two groups. Documenting dental eruption sequences in other anthracothere species will be necessary to determine if such information can provide a meaningful way to test hypotheses of relationships.

Resumen en Español

Dentición decidua y secuencia de erupción dental de Bothriogenys fraasi (Anthracotheriidae, Artiodactyla) de la Depresión de El Fayum, Egipto

Los Anthracotheriidae del Paleógeno están escasamente documentados en las localidades afroarábicas. Esto se debe, en gran parte, a la naturaleza fragmentaria de los especímenes que se han descrito. Sin embargo, los sedimentos de la Formación Jebel Qatrani, Depresión El Fayum, Egipto, conservan los conjuntos de fósiles de Anthracotheriidae más ricos en toda la región afroarábica. A diferencia de otras muestras, la colección de El Fayum incluye muchas denticiones completas, cráneos y esqueletos parciales. Documentado con estas extensas colecciones, este estudio proporciona la primera descripción de la dentición decidua completa y la secuencia de erupción dental para el Anthracotheriidae del Oligoceno temprano Bothriogenys fraasi. Se proporciona una discusión detallada sobre el patrón y el tiempo de crecimiento dental en B. fraasi, y la secuencia ontogenética documentada para B. fraasi se compara con las disponibles para suoideos e hipopótamos, los dos grupos existentes que actualmente se consideran como posibles taxones hermanos de Anthracotheriidae. Los resultados muestran que los Anthracotheriidae y los suoideos comparten un patrón de emergencia dental más parecido entre ellos que con otros grupos, y uno que puede estar cerca de la condición primitiva para los artiodáctilos, mientras que los hipopótamos tienen una secuencia de erupción dental muy diferente como consecuencia de su patrón de vida muy divergente. Cada vez más la investigación sobre la historia de la vida indica que se puede esperar que los taxones estrechamente relacionados compartan rasgos de su patrón de desarrollo dental, por lo que el presente hallazgo sugiere que la hipótesis sobre una relación filogenética entre Anthracotheriidae con Hippopotamidae o Suiformes puede ser potencialmente testada con el estudio de los patrones de erupción dental.

Palabras clave: El Fayum; Egipto, Oligoceno; juvenil; dentición; Artiodactyla

Traducción: Enrique Peñalver (Sociedad Española de Paleontología)

Résumé en Français

Dentition déciduale et séquence d'éruption dentaire de Bothriogenys fraasi (Anthracotheriidae, Artiodactyla) de la dépression du Fayoum, Égypte

Les anthracothères paléogènes sont mal documentés dans les localités afro-arabiques. Cela est dû en grande partie à la nature fragmentaire des spécimens qui ont été décrits. Cependant, les sédiments de la formation Jebel Qatrani, dépression du Fayoum, Égypte, préservent les assemblages les plus riches en anthracothères de toute la région afro-arabique. Contrairement aux autres échantillons, la collection du Fayoum inclut de nombreux squelettes partiels, dentures, et têtes osseuses. À partir de ces collections importantes, cette étude fournit la première description de la dentition déciduale complète et de la séquence d'éruption dentaire de l'anthracothère Bothriogenys fraasi de l'Oligocène ancien. Une discussion détaillée du schéma et du déroulement de la croissance dentaire de B. fraasi est fournie, et la séquence ontogénétique documentée pour B. fraasi est comparée à celles disponibles pour les suoïdes et les hippopotames, les deux groupes actuels actuellement considérés comme des possibles groupes frères des anthracothères. Les résultats montrent que les anthracothères et les suoïdes partagent un schéma d'éruption dentaire similaire qui pourrait être proche de la condition plésiomorphe pour les artiodactyles, alors que les hippopotames ont une séquence d'éruption dentaire très différente en conséquence de leur schéma d'histoire de vie très divergent. Un corpus de recherches de plus en plus important sur les paramètres d'histoire de vie indique qu'il faut s'attendre à ce que des taxons phylogénétiquement proches partagent des caractères de leur schéma de développement dentaire. Nos résultats suggèrent donc qu'un test utile des hypothèses actuellement en compétition concernant les relations entre les Anthracotheriidae d'une part et soit les Hippopotamidae soit les Suiformes d'autre part pourrait potentiellement être développé en se basant sur les schémas d'éruption dentaire.

Mots-clés : Fayoum ; Égypte ; Oligocène ; juvénile ; dentition ; Artiodactyla

Translator: Antoine Souron

Deutsche Zusammenfassung

Milchbezahnung und Zahneruptionssequenzen von Bothriogenys fraasi (Anthracotheriidae, Artiodactyla) aus der Fayum Depression, Ägypten

Paläogene Anthracotheren sind aus afro-arabischen Fundstellen kaum dokumentiert. Dies liegt zum großen Teil an der fragmentarischen Erhaltung der beschriebenen Stücke. Jedoch beinhalten Sedimente in der Jebel Qatrani Formation (Fayum Depression, Ägypten) die reichhaltigste Anthracotheren-Assemblage im gesamten Afro-Arabien. Im Gegensatz zu anderen Proben enthält die Fayum-Sammlung viele komplette Gebisse, Schädel und Teilskelette. Basierend auf dieser umfangreichen Sammlung stellt diese Untersuchung die erste Beschreibung der kompletten Milchbezahnung und Zahneruptionssequenz des früholigozänen anthracotheren Bothriogenys fraasi dar. Die Muster und der Zeitpunkt des Zahnwachstums bei B. fraasi werden diskutiert und die für B. fraasi dokumentierte ontogenetische Sequenz wird mit denen der verfügbaren Suoiden und Hippos verglichen, den zwei heute noch lebenden Gruppen, die gegenwärtig als mögliche Schwestertaxa der Anthracotheren angesehen werden. Die Ergebnisse zeigen, dass Anthracotheren und Suoiden ein ähnlicheres Zahneruptionsmuster aufweisen, das zudem möglicherweise der primitiven Kondition bei Artiodactylen ähnelt, während Hippos eine unterschiedliche Zahneruptionssequenze haben, was auf ihre abweichende Entwicklungsgeschichte zurückzuführen ist. Viele Forschungen zur Lebensgeschichte von Organismen weisen darauf hin, dass Taxa, die sich phylogenetisch nahe stehen, Merkmale bezüglich ihrer Zahnentwicklung teilen. Der vorliegende Fund hingegen ist ein nützlicher Test konkurrierender Annahmen hinsichtlich der Verwandtschaft von Anthracotheriidae mit entweder Hippopotamidae oder Suiformes basierend auf Zahneruptionsmustern.
Schlüsselwörter: Fayum; Ägypten, Oligozän; juvenil; Bezahnung; Artiodactyla

Translator: Eva Gebauer

Arabic

Translator: Authors

 

 

FIGURE 1. 1, location map of the Jebel Qatrani area, Fayum Depression. 2, stratigraphic positions and age estimates for major mammal-bearing fossil localities, following Seiffert (2006), EOB is abbreviation for Eocene Oligocene Boundary. 3, map of Jebel Qatrani area, showing different rock units, common landmarks and the approximate position of anthracothere-bearing fossil localities.

figure1 

FIGURE 2. Dental terminology used to describe features of the deciduous premolars of Bothriogenys fraasi, following Bärmann and Rössner (2011).

 

FIGURE 3. 1-4, right partial maxilla of DPC 5167 with dP2-M1, in (1) lateral, (2) medial, (3) anterior, and (4) occlusal views; 5, right partial maxilla of DPC 20439 (doi.org/10.17602/M2/M12647) with dP3- dP4, in occlusal view; 6-8, right dP4 of DPC 3224 (doi.org/10.17602/M2/M12690), in (6) occlusal, (7) lingual, (8) ventral views; 9, DPC 11416 (doi.org/10.17602/M2/M12641) with dP1- dP4, in occlusal view.

figure3 

FIGURE 4. Left mandibular fragment of DPC 11416 (doi.org/10.17602/M2/M12641) with dP1- dP4, showing stage I of the eruption sequence of Bothriogenys fraasi, in (1) lateral, (2) internal, (3) medial, and (4) occlusal views.

figure4 

FIGURE 5. Right mandibular fragment of DPC 7706 (doi.org/10.17602/M2/M17034) with dP2- M1, showing stage II of the eruption sequence of Bothriogenys fraasi, in (1) lateral, (2) medial, (3-4) internal, and (5) occlusal views.

figure5 

FIGURE 6. Right mandibular fragment of DPC 2705 (doi.org/10.17602/M2/M12688) with dP2- M1, showing stage III of the eruption sequence of Bothriogenys fraasi, in (1) lateral, (2) medial, (3-4) internal, and (5) occlusal views.

 figure6

FIGURE 7. Right mandibular fragment of DPC 13562 (doi.org/10.17602/M2/M12638) with P2, dP3-4, M1-M2, showing stage IV of the eruption sequence of Bothriogenys fraasi, in (1) lateral, (2, 4) internal and X-ray, and (3) medial views.

figure7 

FIGURE 8. Right mandibular fragment of DPC 6207 (doi.org/10.17602/M2/M17032) with P2- M3, showing stage V of the eruption sequence of Bothriogenys fraasi, in (1) lateral, (2) occlusal, (3) medial, (4) internal views; 5-6, right partial maxilla of DPC 10677 (doi.org/10.17602/M2/M12698), in (5) occlusal and (6) medial views.

 

FIGURE 9. Comparison of the different stages (I-V) of the eruption sequence of Bothriogenys fraasi.

figure9

 

Scanning information for Bothriogenys fraasi specimens used in this study. Cite DOI and specimen number when utilizing scans from this table. All files are available directly from:
www.MorphoSource.org.

Specimen DOI File size (MB) File type
  DPC-2705   doi.org/10.17602/M2/M13080 2.30 MB Digital camera image
doi.org/10.17602/M2/M16982 410.32 MB Mesh file
doi.org/10.17602/M2/M12688 502.22 MB Zipped tiff stack
       
  DPC-3224   doi.org/10.17602/M2/M13082 2.56 MB Digital camera image
doi.org/10.17602/M2/M16983 47.15 MB Mesh file
doi.org/10.17602/M2/M12690 77.86 MB Zipped tiff stack
       
  DPC-3606   doi.org/10.17602/M2/M13075 2.68 MB Digital camera image
doi.org/10.17602/M2/M16986 761.77 MB Mesh file
doi.org/10.17602/M2/M12653 779.97 MB Zipped tiff stack
       
  DPC-3947   doi.org/10.17602/M2/M13060 2.71 MB Digital camera image
doi.org/10.17602/M2/M17001 153.51 MB Mesh file
doi.org/10.17602/M2/M12639 259.23 MB Zipped tiff stack
       
  DPC-4894   doi.org/10.17602/M2/M13063 2.68 MB Digital camera image
doi.org/10.17602/M2/M17002 256.65 MB Mesh file
doi.org/10.17602/M2/M12644 206.21 MB Zipped tiff stack
       
  DPC-5167   doi.org/10.17602/M2/M13066 2.64 MB Digital camera image
doi.org/10.17602/M2/M17003 163.21 MB Mesh file
doi.org/10.17602/M2/M12646 275.07 MB Zipped tiff stack
       
  DPC-6147   doi.org/10.17602/M2/M13070 2.56 MB Digital camera image
doi.org/10.17602/M2/M17004 43.24 MB Mesh file
doi.org/10.17602/M2/M12649 363.82 MB Zipped tiff stack
       
  DPC-6207   doiorg/10.17602/M2/M17033 2.74 MB Digital camera image
doi.org/10.17602/M2/M17031 2.740 GB Mesh file
doi.org/10.17602/M2/M17032 769.88 MB Zipped tiff stack
       
  DPC-7706   doi.org/10.17602/M2/M17037 2.72 MB Digital camera image
doi.org/10.17602/M2/M17035 217.59 MB Mesh file
doi.org/10.17602/M2/M17034 513.22 MB Zipped tiff stack
       
  DPC-7730   doi.org/10.17602/M2/M13078 2.30 MB Digital camera image
doi.org/10.17602/M2/M17029 298.16 MB Mesh file
doi.org/10.17602/M2/M12655 435.92 MB Zipped tiff stack
       
  DPC-8638   doi.org/10.17602/M2/M13079 2.75 MB Digital camera image
doi.org/10.17602/M2/M17030 270.24 MB Mesh file
doi.org/10.17602/M2/M12684 202.75 MB Zipped tiff stack
       
  DPC-10616   doi.org/10.17602/M2/M13071 2.70 MB Digital camera image
doi.org/10.17602/M2/M16969 456.16 MB Mesh file
doi.org/10.17602/M2/M12650 614.44 MB Zipped tiff stack
       
  DPC-10633   doi.org/10.17602/M2/M13076 2.64 MB Digital camera image
doi.org/10.17602/M2/M16963 573.96 MB Mesh file
doi.org/10.17602/M2/M12654 732.29 MB Zipped tiff stack
       
  DPC-10677   doi.org/10.17602/M2/M13084 2.64 MB Digital camera image
doi.org/10.17602/M2/M16966 500.91 MB Mesh file
doi.org/10.17602/M2/M12698 436.46 MB Zipped tiff stack
       
  DPC-11280   doi.org/10.17602/M2/M13065 2.65 MB Digital camera image
doi.org/10.17602/M2/M16970 215.02 MB Mesh file
doi.org/10.17602/M2/M12645 235.51 MB Zipped tiff stack
       
  DPC-11407   doi.org/10.17602/M2/M13074 2.71 MB Digital camera image
doi.org/10.17602/M2/M16971 559.86 MB Mesh file
doi.org/10.17602/M2/M12651 782.23 MB Zipped tiff stack
       
  DPC-11412   doi.org/10.17602/M2/M13068 2.74 MB Digital camera image
doi.org/10.17602/M2/M16972 422.1 MB Mesh file
doi.org/10.17602/M2/M12648 511.58 MB Zipped tiff stack
       
  DPC-11416   doi.org/10.17602/M2/M13062 2.61 MB Digital camera image
doi.org/10.17602/M2/M16974 225.28 MB Mesh file
doi.org/10.17602/M2/M12641 282.98 MB Zipped tiff stack
       
  DPC-13562   doi.org/10.17602/M2/M13059 2.77 MB Digital camera image
doi.org/10.17602/M2/M16975 351.17 MB Mesh file
doi.org/10.17602/M2/M12638 443.05 MB Zipped tiff stack
       
  DPC-13570   doi.org/10.17602/M2/M17042 2.98 MB Digital camera image
doi.org/10.17602/M2/M17039 234.05 MB Mesh file
doi.org/10.17602/M2/M17038 325.26 MB Zipped tiff stack
       
  DPC-20439   doi.org/10.17602/M2/M13067 2.63 MB Digital camera image
doi.org/10.17602/M2/M16979 492.04 MB Mesh file
doi.org/10.17602/M2/M12647 723.26 MB Zipped tiff stack
 

TABLE 1. Length and width of teeth (in millimeters) of juvenile specimens of Bothriogenys fraasi from the upper most terrestrial mammal-bearing localities of the Jebel Qatrani Formation, Fayum Depression, Egypt. Specimen numbers are hyperlinked to DOIs representing microCT data and associated mesh files and photographs on MorphoSource. The DOIs can be found in Supplemental Material and should be cited along with this paper and MorphoSource if reused.

Bothriogenys fraasi                      
Upper   dP 1 dP 2 dP 3 dP 4 M 1
DPC 3224
doi.org/10.17602/M2/M12690
Right -- -- -- -- -- -- 15.13 15.55 -- --
DPC 5167
doi.org/10.17602/M2/M12646
Right -- -- 11.22 5.18 15.21 10.40 15.00 13.66 18.90 ?
DPC 20439
doi.org/10.17602/M2/M12647
Right -- -- -- -- 16.27 10.65 15.29 14.40 -- --
                       
Lower   dP 1 dP 2 dP 3 dP 4 M 1
DPC 2705
doi.org/10.17602/M2/M12688
Right -- -- 8.86 4.35 16.25 6.89 21.93 9.17 20.82 11.77
DPC 3606
doi.org/10.17602/M2/M12653
Right -- -- -- -- 17.17 6.29 21.49 8.59 -- --
DPC 3947
doi.org/10.17602/M2/M12639
Left -- -- -- -- 17.03 6.23 21.40 8.69 -- --
DPC 6147
doi.org/10.17602/M2/M12649
Left -- -- -- -- -- -- 20.45 8.23 -- --
DPC 7706
doi.org/10.17602/M2/M17034
Right -- -- 8.26 4.08 17.76 6.47 21.56 8.72 20.18 11.81
DPC 7730
doi.org/10.17602/M2/M12655
Left -- -- 9.43 4.41 17.77 6.94 22.54 9.16 21.48 12.15
DPC 8638
doi.org/10.17602/M2/M12684
Right -- -- 7.91 4.05 15.75 6.26 20.31 7.99 19.08 10.29
DPC 10616
doi.org/10.17602/M2/M12650
Left -- -- -- -- -- -- 20.32 7.66 19.41 10.20
DPC 10633
doi.org/10.17602/M2/M12654
Right -- -- -- -- 15.72 5.77 20.27 7.93 -- --
DPC 11280
doi.org/10.17602/M2/M12645
Left -- -- -- -- -- -- 21.24 8.44 19.15 10.64
DPC 11407
doi.org/10.17602/M2/M12651
Left -- -- -- -- -- -- 20.38 8.18 18.68 10.63
DPC 11412
doi.org/10.17602/M2/M12648
Right -- -- -- -- 15.11 6.51 21.50 8.41 -- --
DPC 11416
doi.org/10.17602/M2/M12641
Left 7.01 2.96 9.20 4.67 16.87 6.54 22.63 8.83 -- --
DPC 13570
doi.org/10.17602/M2/M17039
Left -- -- 9.27 4.30 16.05 6.33 21.17 8.46 -- --
DPC 13562
doi.org/10.17602/M2/M12638
Right -- -- -- -- 15.22 6.07 21.26 8.58 19.06 10.71

 

TABLE 2. Juvenile dental eruption sequence of Bothriogenys fraasi from the upper most terrestrial mammal-bearing localities of the Jebel Qatrani Formation, Fayum Depression, Egypt.

Eruption stage Eruption sequence of Bothriogenys fraasi juveniles Specimen no. Quarry
Stage I dP1 exposed; dP2, dP3 and dP4 erupted; M1 opened DPC 3606 M
  DPC 3947 M
    DPC 11416 I
    DPC 13570 I
    DPC 16633 I
       
Stage II dP1 exposed; dP2, dP3, dP41 erupted; M2 opened DPC 7706 M
  DPC 8638 M
    DPC 11280 M
    DPC 11407 M
       
Stage III P3 and P4 start to form; dP 3, dP4 , M1 present; M2 exposed DPC 2705 M
  DPC 7730 I
    DPC 10616 O
       
Stage IV P2 exposed; P3 and P4 formed; dP3, dP4, M1, M2 present M3 opened DPC 13562 I
       
Stage V Adult form i with P3 and P4 half exposed

Adult form ii with M3 half exposed

Adult form iii with M3 fully exposed

DPC 10677 I
DPC 6207 I
DPC 20950 M
 

author1Hesham M. Sallam, Mansoura University Vertebrate Paleontology Center, Department of Geology, Mansoura University, Mansoura, 35516, Egypt, and Department of Evolutionary Anthropology, Duke University, Durham, NC 27708, USA This email address is being protected from spambots. You need JavaScript enabled to view it.

Hesham Sallam undertook his masters on the stratigraphy, paleontology, and paleoecology of the Cretaceous deposits in the Sinai Peninsula, Egypt. He then completed his PhD in 2010 at the University of Oxford (UK), where his dissertation focused on mammals recovered from the famous Fayum fossil deposits in Egypt. During his PhD, he was an affiliated scientist at Stony Brook University, Ohio University in 2015 and currently at the Department of Evolutionary Anthropology, Duke University. He returned to Egypt in 2010 to take up a position at Mansoura University, teaching vertebrate paleontology, where he now serves as a lecturer. His current research projects are broadly in the area of vertebrate paleontological research in Afro-Arabia, and more specifically are aimed at understanding mammalian evolution in Africa, with a particular emphasis on the Afro-Arabian radiations of hystricognathous and anomaluroid rodents. Moreover, he founded the Mansoura University Vertebrate Paleontology (MUVP) initiative, a combined research, outreach, and conservation endeavor based in the Geology Department of that university. The goals of MUVP include educating Egyptian vertebrate paleontologists, expanding awareness of Egypt's vertebrate paleontological resources, and undertaking preparation, anatomical study, and curation of Egypt's fossil vertebrate paleontological resources. Hesham has been involved in vertebrate paleontological fieldwork in the Late Cretaceous and Paleogene of Egypt, Kenya, Yemen and USA, and geological and invertebrate paleontological work in the Late Cretaceous beds of the Sinai Peninsula in Egypt.

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aukthor2Afifi H. Sileem, Vertebrate Paleontology Section, Cairo Geological Museum, Cairo, Egypt, This email address is being protected from spambots. You need JavaScript enabled to view it.

Afifi received his masters from Al-Azhar University, Egypt in 2010 and completed his PhD in 2016 at the same university. He is currently the Head of the Paleontology Department at the Egyptian Geological Museum, Egypt. Afifi's current research focuses on the evolution and relationships of Paleogene anthracotheriids from the Fayum Depression, Egypt. Afifi has led and been involved in numerous vertebrate paleontological expeditions with Duke University in the Fayum Depression; Michigan University in Wadi Hitan and Pennsylvania University in the Bahariya Oasis of Egypt. He also conducted field work on the Upper Cretaceous deposits.

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author3Ellen R. Miller, Department of Anthropology, Wake Forest University, Winston-Salem, NC 27106, USA, This email address is being protected from spambots. You need JavaScript enabled to view it.

Ellen R. Miller is a Biological Anthropologist specializing in African Paleoanthropology. Ellen received her PhD from Washington University (Saint Louis) in 1996. She is currently Professor of Anthropology at Wake Forest University in Winston-Salem, North Carolina. Ellen's major research focus revolves around the origin and subsequent radiation of Old World Monkeys (Cercopithecoidea) as documented in the fossil record. She also is engaged in study of the transition of archaic to modern African faunas as well exploring the primate context from within which humans arose. She is an active field paleontologists who has led many expeditions to Africa, in particular to Egypt and Kenya. Ellen conducted her PhD field research at the early Miocene site of Wadi Moghra in Egypt where she studied the mammalian fauna associated with the early cercopithecoid Prohylobates tandyi. Currently Ellen is leading the excavation and study of the early Miocene faunal assemblage at Buluk in the Turkana Basin in northern Kenya.

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author4Gregg F. Gunnell, Division of Fossil Primates, Duke Lemur Center, Durham, NC 27705, USA, This email address is being protected from spambots. You need JavaScript enabled to view it.This email address is being protected from spambots. You need JavaScript enabled to view it.">

Gregg F. Gunnell is a Paleomammalogist and Biological Anthropologist specializing in North American, African, and Asian Cenozoic mammal evolution. Gregg received his PhD from the University of Michigan in 1986. He is currently Director of the Division of Fossil Primates at the Duke Lemur Center in Durham, North Carolina. He is also a Research Associate in the Division of Vertebrate Zoology at the American Museum of Natural History (New York City) and a Resource Associate Professor of Anthropology at the City University of New York (CUNY). Gregg's research focuses on the origination, diversification and biogeography of modern groups of mammals. His fieldwork and research activities have taken him to Asia (Pakistan, Kazakhstan, Indonesia, Myanmar, & India), Africa (Tanzania, Egypt, & Kenya), Europe (Belgium, United Kingdom, Germany, Czech Republic, & France), Australia and North America (USA & Mexico). He has studied the fossil record of many mammalian groups including primates, insectivorans, carnivores, and artiodactyls, as well as several wholly extinct groups. Much of his current research focuses on the origin of modern bats and their diversification across the globe. He serves as series editor for Cambridge University Press, Studies in Morphology and Molecules, has edited three books and has published over 100 scholarly papers on his research results.

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