The Sombrillo Area of Critical Environmental Concern is an Essential Area for Paleontologists

In 1988 8,865 acres of the Nambé Badlands were designated[1]Resource Management Plan, March 1987, U.S. Department of the Interior, Bureau of Land Management, Albuquerque District, Taos Resource Area, BLM-NM-PT-87-006-4410 as the Sombrillo Area of Critical Environmental Concern (ACEC) to protect the internationally significant paleontological resources (fossils) found in the area.

Paleontologists later found additional fossil resources north of the 1988 Sombrillo ACEC boundaries. These findings, and identification of cultural sites, resulted in the BLM expanding the Sombrillo ACEC to 18,190 acres in 2010[2]Draft Taos Resource Management Plan and Environmental Impact Statement, June 3, 2010, U.S. Department of the Interior, Bureau of Land Management, Albuquerque District, Taos Resource Area, … Continue reading.

Sedimentary outcrops in the area have resulted in important discoveries of Miocene vertebrate fossils by scientists for over 140 years.

Many important fossil discoveries of extinct mammals and other vertebrates have been made in the Nambé Badlands area.

Please note that fossils in the Nambé Badlands and Sombrillo ACEC are protected under the Paleontological Resource Protection Act.

Fossil of Sthenictis

Fossils of the extinct species Sthenictis a large member of the mustelid (weasel) family have been found in the Sombrillo Area of Critical Environmental Concern[3]Phil Gensler, Gary Morgan, Scott Aby, and Garrett R. Williamson, “New Additions to the Miocene Vertebrate Fauna of the Tesuque Formation, Española Basin, New Mexico, in Paleontology on Public … Continue reading.   Photo credit, Ryan Somma, Creative Commons license.

Paleontologists Have Made Significant Discoveries in the Sombrillo Area of Critical Environmental Concern

The prominent scientist Edward Drinker Cope collected fossils from the Miocene epoch (23.0 to 5.3 million years ago (Ma)).  Cope’s team collected fossils from 53 vertebrates in the Sombrillo ACEC area in 1874. Cope’s findings here included 32 new species of mammals, land tortoises, and a bird.  The fossil records he discovered here are still recognized today as important findings[4]Osborn, Henry Fairfield  [1931]. “Cope: Master Naturalist: Life and Letters of Edward Drinker Cope, With a Bibliography of His Writings”.  Manchester, New Hampshire: Ayer Company … Continue reading

Paleontologists from the Childs Frick Laboratory of the American Museum of Natural History conducted long-term surveys of the Sombrillo ACEC area from 1924-1964.    This research has resulted in an unparalleled collection numbering in the thousands of specimens.

In the 1988 BLM Resource Management Plan the Sombrillo area (Nambé Badlands) was designated as an Area of Critical Environmental Concern (ACEC) for paleontological resources[5]Taos Resource Management Plan and Environmental Impact Statement, 2010, BLM/NM/PL-10-01-1610, Chapter 3, pages 224-225

Beginning in 2008 and continuing to the present, the New Mexico Museum of Natural History (NMMNH) and the BLM have collaborated on a survey of Miocene vertebrate fossils in the BLM Sombrillo ACEC (a significant portion of the Nambé Badlands).

Three superposed members of the Tesuque Formation have produced vertebrate faunas:

  • Nambé Member:  Nambé Fauna, from the Herningfordian North American Land Mammal Age (NALMA), and late early Miocene eras, 16-17 Mega-annum (Ma), (one Ma = 1 million years)
  • Skull Ridge Member: Skull Ridge Fauna, early Barstovian NALMA, early medial Miocene, 15-16 Ma.
  • Pojoaque Member: Pojoaque Fauna, late Barstovian NALMA, meidal Miocene, 12.5-15 Ma.

Native American paleontologists and students with the Native Explorers Program (NEP) located and collected a number of vertebrate fossils from within the Sombrillo ACEC and the La Puebla ACEC.  The NEP students found everything from a small extinct dog, to horses and camels. The fossils they found will be curated in the New Mexico Museum of Natural History and Science in Albuquerque and will provide the BLM with additional information that will enable greater protection of these resources[6]U.S. Department of the Interior, DOINews:  “BLM New Mexico Hosts Aspiring Native American Paleontologists“, Jun 6, 2014 (edited Sept. 5, 2019)

Paleontological field research continues today in the Sombrillo ACEC.

Photo of Edward Drinker Cope

Edward Drinker Cope (July 28, 1840 – April 12, 1897), an American paleontologist was one of the first great vertebrate fossil researchers in the United States.  Cope first collected fossils of vertebrates from the Miocene Epoch (24.0 – 5.3 million years ago )  in the Nambé Badlands area in 1874.  His research there led to the discovery of 32 new species of mammals, land tortoises, and a bird.  Copes’s significant findings in the Nambé Badlands are still recognized today.

Geologic timeline

The fossils researched in the Sombrillo Area of Critical Environmental Concern consist mostly of vertebrates that lived during the Miocene Epoch (23.03 – 5.33 Ma), which occurred during the Neogene Period (23.03-2.58 Ma), which in turn was in the Cenozoic Era (66.0 Ma – present), inside the Phanerozoic Eon (541 Ma – present).

Important Fossil Discoveries in the Nambé Badlands

Aelurdon

An extinct canine that lived 16 million years ago, “hyena-like” with bone-crushing teeth.

A drawing of the Aelurodon species (extinct) that lived in the Nambé Badlands area 16 million years ago.

Fossils of the Aelurodon (Canidae family) have been found in the Sombrillo ACEC. Smithsonian National Museum of Natural History.

Pseudaelurus

A pre-historic cat that lived 20 – 8 million years ago (Ma). It originated in Eurasia and was the first cat to reach North America (18.5 Ma).

Pseudaelurus is regarded as the ancestor of all modern cats. Fossil finds indicate that there were about twelve species of this ancient cat.  Important fossil finds of Pseudaelurus stouti , a tiny feline, were found in the Sombrillo ACEC.

Fossil teeth of a Pseudaelurus have been found in the Sombrillo ACEC. (Photo credit: Staatliches Museum für Naturkunde Stuttgart)

The first of the felids was known as Proailurus. The next most recent descendant is a group of cats known as Pseudaelurus. The genus Pseudaelurus is the last common ancestor of extant felines (mostly small to medium cats, including domestic breeds), pantherines (medium to large cats including lions, tigers, and leopards), and machairodonts (extinct saber-tooth cats). Pseudaelurus consists of twelve accepted species. Originating in Eurasia, species of Pseudaelurus migrated across land bridges into North America, ending what is casually known as the “Cat-gap” from 25 to 18.5 million years ago when few, if any, cat fossils were found [7]Second of the Proto-Cats.  https://paleontology80.rssing.com/chan-6327401/all_p88.html.

Sthenictis

Sthenictis is an extinct genus in the weasel family (mustelids) endemic to North America and Asia during the Miocene epoch living from ~15.97—5.33 Ma

Fossils of the jawbone of the prehistoric Sthenictis, a large mustelid (weasel family) were found in the Sombrillo ACEC[8]Phil Gensler et al, Vertebrate Fauna of the Tesuque Formation, Española Basin, New Mexico.

Fossil of Sthenictis

Fossils of the extinct species Sthenictis a large member of the mustelid (weasel) family have been found in the Nambé Badlands[9]Phil Gensler, Gary Morgan, Scott Aby, and Garrett R. Williamson, “New Additions to the Miocene Vertebrate Fauna of the Tesuque Formation, Española Basin, New Mexico, in Paleontology on Public … Continue reading.   Photo credit, Ryan Somma, Creative Commons license.

Brachypsalis

Brachypsalis is an extinct genus in the weasel family (mustelids) which existed during the Miocene period living from ~15.97—5.33 Ma.

Fossils of Brachypsalis, a large mustelid (weasel family) were found in the Sombrillo ACEC.  Paleontologist Edward Drinker Cope first discovered the (extinct) genus Brachypsalis in 1890.  The area of the now Sombrillo ACEC was a productive area for Cope as a paleontologist.

Mandible fossils, similar to these shown here, of the large mustelid Brachypsalis were found in the Sombrillo ACEC.

Peraceras

An extinct genus of rhinoceros that lived in North America 16 – 10.3 million years ago. Fossils of Peraceras have been discovered in the Sombrillo ACEC.

A drawing of a Peraceras fossil made in 1915. (American Museum of Natural History.; Cope, E. D.; Geological Survey (U.S.); Matthew, William Diller -).  See alsoU.S. Geological Survey of the Territories,  Peraceras supercilliosus, Edward Drinker Cope.

A drawing of a Peraceras (Source: Age of Mammals)

The evolutionary tree of rhinos shows the Peraceras as living during the early to the middle part of the Miocene era.

Merychippus

Fossils of Merychippus, a proto-horse from the Miocene era, have been found in the Sombrillo ACEC. It was a small horse, standing about 1 meter tall, and had three toes.

Merychippus specimen at the American Museum of Natural History, New York. (photo by H. Zell)

Restoration of Merychippus showing it as a small proto-horse.  Many fossils of proto-horses have been found in the Sombrillo ACEC. (Source: Nobu Tamura)

Evolution of Equinae

Four groups of equids (horse family), ‘‘Anchitheriinae,’’ Merychippine-grade Equinae, Hipparionini, and Equini, coexisted in the middle Miocene, but only the Equini remains after 16 Myr of evolution and extinction.  Fossils of Miocene equids have been found in the Sombrillo ACEC. North American Land Mammal Ages are indicated on the bottom this figure. The size of the colored regions represents relative diversity among the groups of equids. Horizontal lines represent time ranges of each genus or clade. This study begins with the Barstovian NALMA to capture the most advanced Equinae (“horse”)[10]Famoso NA, Davis EB (2014) Occlusal Enamel Complexity in Middle Miocene to Holocene Equids (Equidae: Perissodactyla) of North America. PLoSONE 9(2): e90184. doi:10.1371/journal.pone.0090184

The Sombrillo Area of Critical Environmental Concern Remains and Important Area for Paleontological Resources

Paleontologists with the Bureau of Land Management have partnered[11]USING PARTNERSHIPS AND VOLUNTEERS TO MANAGE MIOCENE-AGED (HEMINGFORDIAN-BARSTOVIAN NALMA) PALEONTOLOGICAL RESOURCES ON BLM LANDS IN THE ESPANOLA BASIN OF NEW MEXICO. GENSLER, Philip, Bureau of Land … Continue readingwith paleontologists at the New Mexico Museum of Natural History and Science (NMMNH), and the New Mexico Friends of Paleontology, in site monitoring of the Sombrillo ACEC and other public lands rich in paleontological resources.

Due to the highly erodible badlands in the Sombrillo ACEC paleontological resources are continually eroding away and being destroyed.  The BLM/NMMNH partnership collects new fossil specimens exposed in the Sombrillo ACEC and safeguards them in the BLM paleontology repository at the New Mexico Museum of Natural History and Science.

References

References
1 Resource Management Plan, March 1987, U.S. Department of the Interior, Bureau of Land Management, Albuquerque District, Taos Resource Area, BLM-NM-PT-87-006-4410
2 Draft Taos Resource Management Plan and Environmental Impact Statement, June 3, 2010, U.S. Department of the Interior, Bureau of Land Management, Albuquerque District, Taos Resource Area, BLM/NM/PL-10-01-1610
3, 9 Phil Gensler, Gary Morgan, Scott Aby, and Garrett R. Williamson, “New Additions to the Miocene Vertebrate Fauna of the Tesuque Formation, Española Basin, New Mexico, in Paleontology on Public Lands, 25th Annual Tate Conference, and 11th Conference on Fossil Resources, May 30-June 2, 2019, Casper Wyoming
4 Osborn, Henry Fairfield  [1931]. “Cope: Master Naturalist: Life and Letters of Edward Drinker Cope, With a Bibliography of His Writings”Manchester, New Hampshire: Ayer Company PublishingISBN 978-0-405-10735-1.
5 Taos Resource Management Plan and Environmental Impact Statement, 2010, BLM/NM/PL-10-01-1610, Chapter 3, pages 224-225
6 U.S. Department of the Interior, DOINews:  “BLM New Mexico Hosts Aspiring Native American Paleontologists“, Jun 6, 2014 (edited Sept. 5, 2019)
7 Second of the Proto-Cats.  https://paleontology80.rssing.com/chan-6327401/all_p88.html
8 Phil Gensler et al, Vertebrate Fauna of the Tesuque Formation, Española Basin, New Mexico.
10 Famoso NA, Davis EB (2014) Occlusal Enamel Complexity in Middle Miocene to Holocene Equids (Equidae: Perissodactyla) of North America. PLoSONE 9(2): e90184. doi:10.1371/journal.pone.0090184
11 USING PARTNERSHIPS AND VOLUNTEERS TO MANAGE MIOCENE-AGED (HEMINGFORDIAN-BARSTOVIAN NALMA) PALEONTOLOGICAL RESOURCES ON BLM LANDS IN THE ESPANOLA BASIN OF NEW MEXICO. GENSLER, Philip, Bureau of Land Management, Santa Fe, NM; MORGAN, Gary, New Mexico Museum of Natural History, Albuquerque, NM; MOORE, Jim, New Mexico Friends of Paleontology/ New Mexico Museum of Natural History, Albuquerque, NM; ABY, Scott, Muddy Spring Geology, Dixon, NM; FOSS, Scott, Bureau of Land Management, Salt Lake City, UT. Society of Vertebrate Paleontology, Oct-Nov, 2013, abstract from Poster Session II (Thursday, October 31, 2013)
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