Standing Rock Hadrosaur Site (Cretaceous of the United States)

Also known as Concordia Hadrosaur Site, CHS, SRHS

Where: Corson County, South Dakota (45.5° N, 101.6° W: paleocoordinates 51.3° N, 75.2° W)

• coordinate based on nearby landmark

• outcrop-level geographic resolution

When: Little Beaver Creek Member (Hell Creek Formation), Late/Upper Maastrichtian (70.6 - 66.0 Ma)

• bed-level stratigraphic resolution

Environment/lithology: crevasse splay; fine-grained, medium, silty mudstone

• "deposited in a coastal swamp dissected by, and ultimately overrun by, distributary chennels or rivers...There does not appear to be any obvious evidence for a marine influence on Unit 5, even though it occupies a transitional position from the marine bar- and beach-ridge sequence of the Fox Hills Formation to the obviously fluvial environments of the Hell Creek Formation."

•"Sedimentologic data indicate that burial took place during a modest crevasse splay event in a shallow floodplain pond"

• "Dominant sediment mode is fine to medium clay, with a hint of a second mode at fine silt in some layers. Pulses of coarser sediment are also indicated. 30 to 60 vol% organic fragments...layers of papery-weathering lignitic shale are commonly underlain by a layer of blocky or crumbly, organic-rich mudstone and overlain by a less organic-rich siltstone or silty shale."

Size classes: macrofossils, mesofossils, microfossils

Preservation: mold/impression

Collected by K. Olson, Nellermoe in 1993–2003, 2010–2012

Collection methods: bulk, quarrying, surface (in situ), mechanical,

• Ullmann et al. 2017: "Excavation at the site began upon its discovery in 1993 by a collaboration between private land owners, Concordia College, and Minnesota State University-Moorhead. Concordia continued annual summer excavations at SRHS through 2003, collecting a total of more than 4,000 bones. The site was hence initially named the Concordia Hadrosaur Site, and was published with this name in a stratigraphic report (Colson et al. 2004). However, later investigations of land ownership boundaries found that two of the three excavations performed by Concordia crews actually took place on land owned by the Standing Rock Sioux Reservation. Accordingly, fossils collected in these first 11 years were split between collections of the Biology Department of Concordia College in Moorhead, Minnesota, and the Paleontology Department at the headquarters of the Standing Rock Sioux Reservation in Fort Yates, North Dakota. In 2016, SRHS bones under the care of Concordia College (studied herein) were transferred to the vertebrate paleontology collection of the North Dakota Heritage Center and State Museum in Bismarck, North Dakota.

•After a six year hiatus of excavations, in 2010 the Standing Rock Paleontology Department (SRPD) reinitiated annual summer excavations at the eastern end of the bluff. Via an invitation by the lead Concordia project researcher (RN), Drexel University joined the suite of programs investigating the bonebed and the head author (PVU) led a collaborative expedition between Drexel, Concordia, and the Standing Rock Reservation to the site in the summer of 2012. As all excavations since 2010 (including our collaborative dig in 2012) have been pioneered by the SRPD and Standing Rock reservation staff, we have renamed the bonebed the Standing Rock Hadrosaur Site in honor of their ardent support."

Primary reference: R. Gould, R. Larson, and R. Nellermoe. 2003. An allometric study comparing metatarsal II's in Edmontosaurus from a low-diversity hadrosaur bone bed in Corson Co., S. D. Journal of Vertebrate Paleontology 23(3, suppl.):56A [M. Carrano/M. Carrano]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 47034: authorized by Matthew Carrano, entered by Matthew Carrano on 01.02.2005

Creative Commons license: CC BY (attribution)

Taxonomic list

unclassified
  -
Coniferophyta indet.1
"cones of conifers"
 Coniferales -
 Coniferales - Cupressaceae
Metasequoia sp.3 Miki 1941 dawn redwood
Gastropoda
 Architaenioglossa - Viviparidae
Campeloma sp.1 Rafinesque 1819 snail
Lioplacodes sp.1 Meek and Hayden 1864 snail
Viviparus sp.1 Montfort 1810 snail
Bivalvia
 Cardiida - Sphaeriidae
Sphaerium sp.1 Scopoli 1777 fingernail clam
 Unionida - Unionidae
Unionidae indet.1 Rafinesque 1820 freshwater mussel
Reptilia
 Choristodera -
Neochoristodera indet.3 Evans and Hecht 1993 choristodere
 Theropoda - Tyrannosauridae
Tyrannosauridae indet.2 Osborn 1906 tyrannosaurid
"a smaller tyrannosaurid"
Tyrannosaurus rex2 Osborn 1905 tyrant lizard king
"most likely"
 Theropoda - Dromaeosauridae
Dromaeosauridae indet.3 Colbert and Russell 1969 maniraptoran
teeth
 Theropoda - Troodontidae
Troodontidae indet.3 Gilmore 1924 maniraptoran
teeth
Aves
  -
Aves indet.1 Linnaeus 1758 bird
Reptilia
 Ornithischia - Hadrosauridae
Edmontosaurus annectens3 Marsh 1892 hadrosaurine
 Loricata -
Crocodylia indet.1 crocodilian
 Crocodylia - Alligatoridae
Brachychampsa montana3 Gilmore 1911 crocodilian
teeth
 Loricata -
Borealosuchus sternbergi3 crocodilian
teeth
 Testudines - Trionychidae
Trionychidae indet.3 Gray 1825 softshell turtle
Costal, carapace fragments
 Testudinata -
Compsemys victa3 Leidy 1856 turtle
Mammalia
 Tribosphenida -
Theria indet.3 mammal
premolar
Eutheria indet.3 Huxley 1880 eutherian
lower molar
Metatheria indet.3 metatherian
molar talonid
 Multituberculata -
Multituberculata indet.3 multituberculate
Teeth, partial dentary
Actinopteri
 Lepisosteiformes - Lepisosteidae
Lepisosteus occidentalis3 Leidy 1856 gar
"fish scales"
 Amiiformes - Amiidae
"Kindleia fragosa" = Cyclurus fragosus3
"Kindleia fragosa" = Cyclurus fragosus3 Jordan 1927 bowfin
vertebrae
Chondrichthyes
 Rajiformes - Rhinobatidae
Myledaphus bipartitus3 Cope 1876 guitarfish
teeth