Santiago Formation, California

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Santiago Formation
Stratigraphic range: Late Eocene-Late Oligocene (Uintan-Duchesnean)
Type Geological formation
Lithology
Primary Siltstone, mudstone
Other Sandstone
Location
Coordinates 33°06′N117°18′W / 33.1°N 117.3°W / 33.1; -117.3
Approximate paleocoordinates 33°18′N104°06′W / 33.3°N 104.1°W / 33.3; -104.1
Region Orange & NW San Diego County, California
Country United States
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Santiago Formation, California (the United States)
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Santiago Formation, California (California)

The Santiago Formation is a geologic formation in Orange and northwestern San Diego County, California. The siltstones, mudstones and sandstones of the formation preserve fossils of Walshina esmaraldensis and Diegoaelurus vanvalkenburghae , dating back to the Late Eocene to Late Oligocene periods (Uintan to Duchesnean in the NALMA classification). [1]

Contents

Depositional environment

The only paleoenvironmental interpretation based exclusively on specimens from the Santiago Formation is a study of land snails from SDSNH locality 3276 (Member C, Oceanside, San Diego County), which found the distribution of shell sizes and shapes to be consistent with interpretations of subtropical to tropical conditions and paleotemperatures in excess of 25 °C (77 °F). [2]

Fossil content

Mammals

Ferae

Ferae reported from the Santiago Formation
GenusSpeciesPresenceMaterialNotesImages
Ceruttia C. sandiegoensisMember C. [3] Jaw elements & teeth. [3] A carnivoraform also found in the Mission Valley Formation.
Diegoaelurus D. vanvalkenburghae"Member C". [4] A nearly complete dentary. [4] An oxyaenid.
Holotype of Diegoaelurus vanvalkenburghae.png
Lycophocyon L. hutchisoniUpper portions of "member C". [5] Multiple specimens. [5] A basal caniform.
Lycophocyon skull lateral.png
Procynodictis P. progressusMember C. [3] Jaw elements & teeth. [3] A miacid also known from the Sespe & Mission Valley formations.

Primatomorphs

Primatomorphs reported from the Santiago Formation
GenusSpeciesPresenceMaterialNotesImages
Chumashius C. balchiV-72088. [6] Isolated teeth. [6] An omomyid also known from the Sespe Formation.
Dyseolemur D. pacificusV-72088. [6] Isolated molars. [6] An omomyid also known from the Sespe Formation.
Walshina W. esmaraldensisMember C. [7] Teeth. [7] An omomyid also known from the Mission Valley & Sespe formations.

Ungulates

Ungulates reported from the Santiago Formation
GenusSpeciesPresenceMaterialNotesImages
Hesperaletes H. borineyiMember C. [8] Numerous specimens. [8] A tapiroid.
Parvicornus P. occidentalisMember C. [9] Numerous specimens. [9] A brontothere.
Protoreodon P. walshiMember C. [10] Numerous specimens. [10] An oreodont.
P. cf. walshiMember C. [10] Jaw elements. [10] An oreodont.

Invertebrates

Invertebrates reported from the Santiago Formation
GenusSpeciesPresenceMaterialNotesImages
Upogebia U. aronaeMember B. [11] Numerous specimens. [11] A mud shrimp.

See also

References

  1. ↑ Kelly Ranch Core at Fossilworks.org
  2. ↑ López Torres et al., 2018, p.5
  3. 1 2 3 4 Tomiya, Susumu (20 May 2013). "New carnivoraforms (Mammalia) from the middle Eocene of California, USA, and comments on the taxonomic status of 'Miacis' gracilis". Palaeontologia Electronica. 16 (2): 1–14. doi: 10.26879/364 . ISSN   1094-8074.
  4. 1 2 Zack, Shawn P.; Poust, Ashley W.; Wagner, Hugh (15 March 2022). "Diegoaelurus, a new machaeroidine (Oxyaenidae) from the Santiago Formation (late Uintan) of southern California and the relationships of Machaeroidinae, the oldest group of sabertooth mammals". PeerJ. 10: e13032. doi: 10.7717/peerj.13032 . ISSN   2167-8359. PMC   8932314 . PMID   35310159. S2CID   247480756.
  5. 1 2 Tomiya, Susumu (14 September 2011). "A New Basal Caniform (Mammalia: Carnivora) from the Middle Eocene of North America and Remarks on the Phylogeny of Early Carnivorans". PLOS ONE. 6 (9): e24146. Bibcode:2011PLoSO...624146T. doi: 10.1371/journal.pone.0024146 . ISSN   1932-6203. PMC   3173397 . PMID   21935380.
  6. 1 2 3 4 Lillegraven, Jason A. (1980). "Primates from Later Eocene Rocks of Southern California" . Journal of Mammalogy. 61 (2): 181–204. doi:10.2307/1380040. ISSN   0022-2372. JSTOR   1380040.
  7. 1 2 López-Torres, Sergi; Silcox, Mary T.; Holroyd, Patricia A. (2018). "New omomyoids (Euprimates, Mammalia) from the late Uintan of southern California, USA, and the question of the extinction of the Paromomyidae (Plesiadapiformes, Primates)". Palaeontologia Electronica. 21 (3). doi: 10.26879/756 . ISSN   1094-8074.
  8. 1 2 Colbert, Matthew W. (11 September 2006). "Hesperaletes (Mammalia: Perissodactyla), a new tapiroid from the middle Eocene of southern California". Journal of Vertebrate Paleontology. 26 (3): 697–711. doi:10.1671/0272-4634(2006)26[697:HMPANT]2.0.CO;2. ISSN   0272-4634. S2CID   85719229.
  9. 1 2 Mihlbachler, Matthew C.; Deméré, T. A. (January 2009). "A new species of Brontotheriidae (Perissodactyla, Mammalia) from the Santiago Formation (Duchesnian, Middle Eocene) of Southern California". Proceedings of the San Diego Society of Natural History (41): 1–36.
  10. 1 2 3 4 Theodor, Jessica M. (1999). "Protoreodon walshi, a New Species of Agriochoerid (Oreodonta, Artiodactyla, Mammalia) from the Late Uintan of San Diego County, California" . Journal of Paleontology. 73 (6): 1179–1190. Bibcode:1999JPal...73.1179T. doi:10.1017/S0022336000031061. ISSN   0022-3360. JSTOR   1306828. S2CID   133075207.
  11. 1 2 Haug, Carolin; Nyborg, Torrey; Vega, Francisco J. (2013). "An exceptionally preserved upogebiid (Decapoda: Reptantia) from the Eocene of California". Boletín de la Sociedad Geológica Mexicana. 65 (2): 235–248. doi: 10.18268/BSGM2013v65n2a5 . ISSN   1405-3322. JSTOR   24921220.

Bibliography

Further reading

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