any of us are aware that the State of credited with jump-starting American He sent the sack, along with some MNew Mexico has a state gemstone science in the late 19th century. additional specimens from near Gallina, to (Turquoise), a state flower (Yucca), a state In February 1881, while living in Cope in Philadelphia. Cope named them bird (Roadrunner), and even a state ques- Abiquiu, Baldwin explored the Upper two species of a genus of small meat-eating tion (Red or Green?). But how many know Triassic deposits of what is called the dinosaur (theropod) previously named by that New Mexico also has an official state Chinle Formation a few miles north of Marsh; Coelurus longicollis and Coelurus fossil? And that this particular fossil is one town, in exposures along the Chama bauri, writing that Coelurus bauri was of the scientifically best-known and most River at a locality he knew as Arroyo Seco. “… about the size of a greyhound.” After important dinosaurs in the world? New Baldwin often collected in winter, when further consideration, Cope moved Mexico has an incredibly rich fossil record a steady source of water was available as both species to a different genus, first and many remarkable fossil organisms have snow. He found a small concentration Tanystrophaeus and then the new genus been recovered here. But one in particular, of delicate bones, which he picked up Coelophysis. The nameCoelophysis is a relatively small, and at first glance, and placed in a sack. He included a note derived from two Greek roots meaning unassuming, animal was chosen by the written in flowing black script,“Contains “hollow form,” referring to the hollow New Mexico state legislature on March 17, Triassic or Jurassic bones all small and bones of the small animal. 1981, to be the New Mexico State fossil. tender — Those marked little bones are many That honor was bestowed on the uniquely of them almost microscopic. All in this sack Ghost Ranch Coelophysis Quarry New Mexican dinosaur Coelophysis bauri found together in same place. About four Several decades later, in 1947, Edwin (pronounced “see-low-fy-sis”). This is a hundred feet below gypsum stratum Arroyo Colbert, a curator of the American brief account of its initial finding, and Seco Rio Arriba Co New Mexico February Museum of Natural History (AMNH), subsequent discovery of one of the most 1881. No feet — no head — only one tooth. visited the Arroyo Seco area, which is near famous dinosaur quarries in the world, the D. Baldwin—Abiquiu.” Ghost Ranch, while on his way to explore Ghost Ranch Coelophysis Quarry. When discovered, Coelophysis was one of the old- est dinosaurs in the world, and the remains of this animal continue to inform us about the world of the Late Triassic (about 225 to 202 million years ago) and the rise of the ruling reptiles, the dinosaurs. Discovery The bones of Coelophysis were first discov- ered by David Baldwin, a little-known figure who worked as a packer for the 1875 Wheeler Survey in northern New Mexico. Baldwin later roamed throughout northwestern New Mexico and collected and sold vertebrate fossils first to Othniel Charles Marsh of Yale University, and later, through the 1880s, to Marsh’s nem- esis Edward Drinker Cope of Philadelphia. The rivalry and feud between Marsh and Cope, sometimes referred to as “The Bone A “flock” of Coelophysis bauri running across a Late Triassic landscape near what would become Wars,” are legendary and sometimes are Ghost Ranch, New Mexico. Illustration by Matt Celeskey and Mary Sundstrom.
Published by the New Mexico Bureau of Geology and Mineral Resources • A Division of New Mexico Tech the Triassic in what is now the Petrified Forest National Park of Arizona. George Whitaker, a preparator on the American Museum’s staff and part of Colbert’s field crew, stumbled across a remarkable site in the Chinle Formation on Sunday, June 22, shortly before noon. Several days of careful excavation revealed what has become one of the most famous dinosaur localities in the world — the Ghost Ranch Coelophysis Quarry (also known as the Whitaker Quarry). Crews from the AMNH continued collecting through the next two summers, retrieving numerous blocks, some weighing several thousand pounds, containing complete skeletons of Coelophysis and other animals. The Ghost Ranch Coelophysis Quarry was reopened in 1981 by crews from the Carnegie Museum of Natural History Portion of a block from the Ghost Ranch Coelophysis Quarry collected in 1981 on display at the working cooperatively with several other New Mexico Museum of Natural History and Science, showing a partial skeleton of Coelophysis institutions, including the then newly bauri including the base of the tail, hind limbs and pelvic bones, dorsal vertebrae, and skull. founded New Mexico Museum of Natural History, the Museum of Northern Some workers have estimated that What’s in a Name? Arizona, and others. They recovered about a thousand complete or nearly com- The name and identity of Coelophysis has plete skeletons lie within the Ghost Ranch been controversial. The original fossils Coelophysis Quarry, a truly extraordinary collected by Baldwin, and described accumulation of dinosaurs. Coelophysis is by Cope, are fragmentary and may not represented by young to old individuals, be complete enough to allow precise with bodies commonly intertwined and identification. In the early 1990s, a pair tangled. The quarry is overwhelmingly of New Mexican paleontologists therefore dominated by Coelophysis, but it also argued that Coelophysis bauri is a “nomen contains other animals including the dubium” (doubtful name), and proposed small invertebrate chonchostracans (clam a new name for the more complete Ghost shrimp) and ostracodes (seed shrimp), Ranch specimens, Rioarribasaurus colberti. complete fish, a variety of archosaurs However, another team of paleontologists (archosaurs are a group of vertebrate argued that since the name Coelophysis animals that includes crocodiles, dinosaurs bauri has been applied to the Ghost Ranch and birds, and their close relatives), includ- specimens since 1947, it is best to designate ing a crocodile-like phytosaur, long-limbed one of the Coelophysis Quarry specimens crocodile relatives (Effigia and Vancleavea), a new type, or neotype, to maintain small reptiles like drepanosaurs and sphen- taxonomic stability. They petitioned the odontids, and at least one other small, Commission of Zoological Nomenclature, meat-eating dinosaur, Daemonosaurus. which ruled in their favor in June 1996. What led to this accumulation of In the late 1990s, two paleontologists fossilized animals in a single location? announced that they had discovered the Taphonomic studies (studies that look into area where Baldwin had collected the what happens to organisms after death Ghost Ranch Coelophysis Quarry undergoing original type specimen of Coelophysis bauri, excavation in late June, 1981. Photo courtesy of until their discovery as a fossil) of the and named a new dinosaur from a partial Timothy Rowe. quarry indicated that the bone bed is the skeleton that they had collected from the numerous additional blocks that have been result of transport of carcasses by running area, Eucoelophysis baldwini (meaning widely distributed in museums across the water and burial in silt, possibly in a small “Baldwin’s true Coelophysis”). However, United States for preparation and research. depression occupied by a pond. What several years later, a pair of other studies Several of the original blocks collected by killed the many hundreds of Coelophysis demonstrated that Euceolophysis is not a the AMNH in the 1940s were opened only and other animals? That cannot yet be dinosaur, but rather a close dinosaur rela- within the last ten years or so, and found determined. Possibly the animals died in tive. Most paleontologists consider that the to contain skeletons of animals other a drought. Perhaps animals congregated exact position of Baldwin’s Arroyo Seco than Coelophysis, and several of the larger around a shrinking water source when remains a mystery, although it likely was blocks collected by the Carnegie Museum flood waters overcame and drowned them along the cliffs near Ghost Ranch. continue to undergo preparation at the and transported them to the Coelophysis time of this writing. Quarry site. new mexico earth matters 2 summer 2017 Paleobiology that of birds. The neck vertebrae had side pockets that may have held airs sacks tied to Coelophysis is a small dinosaur, belonging the respiratory system, such as are found in 84 to the group Theropoda, that contains birds. Birds and many dinosaurs, including all meat-eating dinosaurs and birds. The Coelophysis, had an ultra-efficient breathing ! many skeletons of Coelophysis provide for Ghost Ranch system in which air is circulated in one an incomparable knowledge of its skeletal direction across the lungs, enabled by the anatomy. Coelophysis resembles other early action of air sacks that were distributed dinosaurs in being bipedal (moved by throughout the body, and indeed even Abiquiu means of its two rear legs) with a fully erect Reservoir pervading many of the bones. These helped gait. Their bodies were long, with a rela- pump air through a rigid lung located tively small head atop a long and sinuous within the chest cavity, and even allowed neck. A long tail helped to balance their oxygen to pass across the lungs during both 84 bodies over their hind legs. Early dinosaurs inhalation and exhalation. 96 differed from other archosaurs in having a ! Some specimens from the Ghost Ranch Abiquiu specialized hip-joint where the head of the Coelophysis Quarry even preserve the femur bent at right angles and was securely extremely delicate, thin, plate-like bones socketed within a cartilage-lined hole that helped to support the eye, the sclerotic within the pelvic bones. The ankle bones Location map of Ghost Ranch area. ring. These reveal the size and shape of the were tightly bound to the end of the distal eye, indicating that Coelophysis was likely hind limb bones, the tibia and fibula, thus their nearest relatives. A long-accepted an animal that was active by day (diurnal), preventing motion between the ankle and phylogeny divides dinosaurs into two main with excellent vision. limb bones, but creating a hinge between branches or clades; the Saurischia (“lizard- Based on studies published in 1989 and the ankle bones and the bones of the hind hipped”) and Ornithischia (“bird-hipped”) 1995, Coelophysis was deemed a cannibal feet. This allowed for very quick and steady dinosaurs. Theropod dinosaurs (including based on the apparent existence of bones motions of the long feet, but prevented birds, ironically) are members of the of juvenile Coelophysis within the gut flexibility. In other words, early dinosaurs Saurischia, along with sauropod dinosaurs of a larger adult. However, more recent were fleet-footed animals that sacrificed and their closest relatives. However, a 2017 examination of this specimen revealed that maneuverability for speed. Coelophysis had study shook up this long-standing hypoth- the alleged meal may not actually lie within forelimbs that articulated with a backward- esis of dinosaur relationships, and posits the stomach area of the larger animal, but facing joint at the shoulder. The forelimbs a radically different phylogeny in which may be underneath it and showing through ended in grasping hands with three sauropod and their closest kin are lower the ribs of the overlying body. Moreover, functional, clawed fingers used for catching on the tree, and theropod and ornithiscian the smaller animal has also recently been and holding prey. The teeth were small dinosaurs are united in a more closely identified as a small close relative of a and blade-like, with serrated cutting edges, related group called the Ornithoscelida. crocodile, rather than a young Coelophysis. and were recurved—well-formed for biting This phylogenetic analysis, as well as others Intriguingly, in 2009, a group of scientists and slicing small prey animals. All evidence examining the relationships among early reported the bones of a small animal, points to Coelophysis being a swift predator dinosaurs, typically rely heavily on data pro- possibly Coelophysis, in material that was that fed on smaller animals. The great vided by the skeletons from the Coelophysis regurgitated and excreted from a Ghost number of animals buried together at the Quarry because of their completeness and Ranch Coelophysis skeleton. quarry suggests that the animals sometimes excellent preservation. Time will tell if this Dinosaur paleontologists have long congregated in large “flocks.” recent and paradigm-shifting phylogeny is worked to build a tree (known as a Many of the bones of Coelophysis are correct, but regardless, Coelophysis retains a phylogeny) showing the evolutionary hollow with thin, delicate walls. This similar position in both phylogenies near relationships among dinosaurs and resulted in a very light-weight skeleton, like the base of Theropoda and demonstrates
Left: Close-up of the skull of Coelophysis bauri showing teeth and overlapping plates of the sclerotic ring that supported the eye. Right: Sketch of reconstructed head of Coelophysis bauri. Illustration by Matt Celeskey. new mexico earth matters 3 summer 2017 Q Aves Aves Cenozoic Tyrannosaurus Tyrannosaurus Velociraptor Velociraptor Ornithischia Ornithischia Mesozoic Jurassic Cretaceous Paleogene Neogene Sauropodomorpha Sauropodomorpha Coelophysis Coelophysis Theropoda Theropoda
Dinosauria Saurischia Dinosauria Ornithoscelida
Triassic A B
Two different time-calibrated dinosaur phylogenies. A) The long-accepted phylogeny with most dinosaurs placed within one of two main branches, the Saurischia (Sauropodomorpha and Theropoda) and Ornithischia. B) A recently proposed new phylogeny in which Sauropodomorpha are basal and Ornithischian dinosaurs are more closely related to Theropoda within the Ornithoscelida. Regardless, Coelophysis is a basal, early theropod dinosaur in both phylogenetic schemes. just how quickly dinosaurs radiated into compared to other archosaurs. Dinosaurs plant-eating dinosaurs appear to have been their primary divisions, after their Middle did not come into their own and reach domi- restricted to only higher latitudes. Indeed, Triassic origin. nance until after the next mass extinction at it may be that the high variability observed The large number of Coelophysis speci- the end of the Triassic, about 200 million in several, basal, Late Triassic theropods, mens provides not only a complete picture years ago, when most other major groups including Coelophysis, was an adaptation to of the anatomy of an early dinosaur, but also of archosaurs became extinct. an unstable environment and contributed important insights into the animal’s ontogeny The Late Triassic Earth was still to their subsequent survival and success in (growth and development) and variability assembled into the supercontinent the Early Jurassic. within a species. While some studies have Pangaea, allowing animals to essentially —Tom Williamson concluded that Coelophysis developed into a walk between all the major continents, sexually dimorphic species with one sex larger unimpeded by ocean barriers. This largely Tom Williamson is a Curator of Paleontology and more robust than the other, another, explains the rapid dispersal and appearance at the New Mexico Museum of Natural more recent analysis, suggests that Coelophysis of dinosaurs throughout the Late Triassic History and Science. He is engaged in and other early members of Dinosauria show world, soon after their first evolutionary research on Cretaceous and Paleogene much higher levels of size variation than later appearance at or near the Middle Triassic. vertebrates with a special interest in dinosaurs, or even among close dinosaur Late Triassic faunas tended to be nearly dinosaurs and mammals, and the recovery relatives, the crocodilians. cosmopolitan (extending across all or and evolution of mammals following the most of the world). Indeed, a dinosaur Cretaceous-Paleogene (K-Pg) extinction. He Coelophysis’ World very closely related to Coelophysis bauri, has conducted research on the K-Pg record Dinosaurs were one group among many possibly even placed within the same in the San Juan Basin for over 25 years. He within the Archosauria, a group of reptiles genus, “Syntarsus” rhodesiensis, is thanks Dr. Sterling Nesbitt and Dr. Stephen that rose following “The Great Dying,” the represented by numerous skeletons from Brusatte for reviewing this paper. great mass extinction at the close of the Zimbabwe, Africa. Coelophysis lived over Permian Period about 250 million years a span of about 5 million years at the very For more information on Coelophysis, ago when over 95% of all marine species end of the Triassic Period. see the following websites: and 70% of terrestrial (land-based) verte- The Late Triassic world may have brate species became extinct. It was during provided a particularly harsh climate with The New Mexico Museum of Natural History a rapid evolutionary radiation following rapidly fluctuating extreme climatic condi- and Science website on Coelophysis: http:// the extinction that many new groups of tions, at least at the lower latitudes occupied nmstatefossil.org animals, including mammals, arose from by New Mexico. This might explain why the ashes in a dramatically new world. no herbivorous dinosaurs, but only a low The Ghost Ranch Museum of Paleontology Interestingly, dinosaurs did not dominate diversity of meat-eating theropod dinosaurs, website: www.ghostranch.org/explore/ the world of the Late Triassic. Instead, they such as Coelophysis, have been found museums/museum-of-paleontology/ were not particularly diverse or remarkable in Late Triassic tropical areas, and why new mexico earth matters 4 winter 2017 bureau news Aquifer Mapping Program receives Healy Foundation support has allowed gift from Healy Foundation us to help improve the state’s working The New Mexico Bureau of Geology knowledge of groundwater resources, com- and Mineral Resources (NMBGMR) at municating to the public, and continuing New Mexico Tech has received an impor- detailed scientific study of specific areas This tant gift to support investigation of New is truly a public-private partnership invest- Mexico’s water resources. In July 2017, the ment in New Mexico’s water future. Healy Foundation provided a generous gift For more information visit the New in support of two ongoing, and one new, Mexico Bureau of Geology’s Aquifer water-focused projects for the state. This gift Mapping Program at http://geoinfo.nmt.
allows the NMBGMR’s Aquifer Mapping edu/resources/water/amp/home.html. Program to continue its public-private partnership of hydrologic research with Volume 17, Number 2 the New Mexico-based, charitable Healy Published twice annually by the New Mexico Bureau of Geology Foundation. and Mineral Resources Nelia Dunbar Director and State Geologist a division of New Mexico Institute of Mining and Technology Dr. Stephen G. Wells President 801 Leroy Place Socorro, New Mexico 87801-4750 Bureau Albuquerque office 2808 Central SE Albuquerque, New Mexico 87106 Rockin Around NM 2017, Socorro (505) 366-2530 This year, bureau geoscientists led teachers on Board of Regents Ex Officio NM Bureau of Geology hydrologist Sara field trips focused on the tectonic history and water resource management of the Socorro Susana Martinez Chudnoff, in center, shown here training rural Governor of New Mexico water operators on techniques of groundwater area. In the photo above, emeritus bureau level measurements and documentation. Dr. Barbara Damron geologist, Dr. David Love, leads a participant Secretary of Higher Education The first of the three projects funded by through a slot canyon out in the Quebradas area, east of Socorro, NM. Appointed this gift strongly focuses on groundwater level Deborah Peacock monitoring in small and rural communities. President, 2017–2022, Corrales NMBGMR staff members are providing Jerry A. Armijo outreach and education to rural well opera- Secretary/Treasurer, 2015–2020, Socorro tors, creating a population of trained citizen David Gonzales 2015–2020, Farmington scientists, capturing important regional water Donald Monette level trends. These measurements, which can 2015–2018, Socorro be uploaded by well owners through a web Emily Silva, student member portal, will be publicly accessed through the 2017–2018, Alamagordo NMBGMR’s website. Editor The goal of the second project is to Paul Bauer produce 3D visualizations and explanations of the geology and shape of several of New Production, Layout & Design Mexico’s important aquifers. Many of New Gina D’Ambrosio Mexico’s neighboring states have aquifer Polished petrified logs in place on Graphics maps, and use these to build understanding bureau grounds Leo Gabaldon of groundwater resources. Visit our website at: geoinfo.nmt.edu Have you noticed three large polished petri- The third study funded by this gift will fied stumps near the fountain in front of the Earth Matters is a free publication. begin a new, regional-scale hydrogeological For subscription information please call New Mexico Bureau of Geology building? If investigation of the Sunshine Valley, north (575) 835-5490, or e-mail us at not, come by and have a seat! Thanks to NM of Questa, NM. The project will involve [email protected] Tech Property, Facilities Management, and collection of geological and hydrological data Cover photo of Chimney Rock, New Mexico Brian Wheeler for moving the logs, and to that will be used to better understand the © Matthew Zimmerer Alan Perryman and others for polishing them! groundwater resources of this region. new mexico earth matters 5 summer 2017 NONPROFIT ORGANIZATION New Mexico Bureau of Geology & Mineral Resources U.S. Postage New Mexico Institute of Mining & Technology 801 Leroy Place PAID Socorro, New Mexico 87801-4750 permit no. 1888 Return service requested Albuquerque, NM
Mining Districts anD ProsPect areas
in new Mexico
Virginia T. McLemore
New Mexico Bureau Geology and Mineral Resources A Division of New Mexico Institute of Mining and Technology Resource Map 24 2017 NEW!
Memoir 50—Energy and Mineral Resources of New Mexico, New Mexico Bureau of Geology and Mineral Resources and the New NMBGMR Resource Map 24—Mining Districts and Mexico Geological Society, edited by Virginia T. McLemore, Stacy Prospect Areas of New Mexico, by Virginia T. McLemore. Timmons, and Maureen Wilks. NMBGMR Memoir 50/NMGS Printed Map with booklet $18.95. Special Publication 13. Individually $25, 6-volume boxed set $125.
For more information about the bureau and our publications: Visit our website at http://geoinfo.nmt.edu Call (575) 835-5490, e-mail us at [email protected], or visit the bureau store at the corner of Bullock and Leroy on the campus of New Mexico Tech, 801 Leroy Place, Socorro, NM, 87801 new mexico earth matters summer 2017