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 |
Approximate paleocoordinates | 33°18′N104°06′W / 33.3°N 104.1°W |
Region | Orange & NW San Diego County, California |
Country | United States |
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]
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]
Ferae reported from the Santiago Formation | |||||
---|---|---|---|---|---|
Genus | Species | Presence | Material | Notes | Images |
Ceruttia | C. sandiegoensis | Member 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. | |
Lycophocyon | L. hutchisoni | Upper portions of "member C". [5] | Multiple specimens. [5] | A basal caniform. | |
Procynodictis | P. progressus | Member C. [3] | Jaw elements & teeth. [3] | A miacid also known from the Sespe & Mission Valley formations. | |
Primatomorphs reported from the Santiago Formation | |||||
---|---|---|---|---|---|
Genus | Species | Presence | Material | Notes | Images |
Chumashius | C. balchi | V-72088. [6] | Isolated teeth. [6] | An omomyid also known from the Sespe Formation. | |
Dyseolemur | D. pacificus | V-72088. [6] | Isolated molars. [6] | An omomyid also known from the Sespe Formation. | |
Walshina | W. esmaraldensis | Member C. [7] | Teeth. [7] | An omomyid also known from the Mission Valley & Sespe formations. | |
Ungulates reported from the Santiago Formation | |||||
---|---|---|---|---|---|
Genus | Species | Presence | Material | Notes | Images |
Hesperaletes | H. borineyi | Member C. [8] | Numerous specimens. [8] | A tapiroid. | |
Parvicornus | P. occidentalis | Member C. [9] | Numerous specimens. [9] | A brontothere. | |
Protoreodon | P. walshi | Member C. [10] | Numerous specimens. [10] | An oreodont. | |
P. cf. walshi | Member C. [10] | Jaw elements. [10] | An oreodont. | ||
Invertebrates reported from the Santiago Formation | |||||
---|---|---|---|---|---|
Genus | Species | Presence | Material | Notes | Images |
Upogebia | U. aronae | Member B. [11] | Numerous specimens. [11] | A mud shrimp. | |
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Adapiformes is a group of early primates. Adapiforms radiated throughout much of the northern continental mass, reaching as far south as northern Africa and tropical Asia. They existed from the Eocene to the Miocene epoch. Some adapiforms resembled living lemurs.
Plesiadapiformes is an extinct basal pan-primates group, as sister to the rest of the pan-primates. The pan-primates together with the Dermoptera form the Primatomorpha. Purgatorius may not be a primate as an extinct sister to the rest of the Dermoptera or a separate, more basal stem pan-primate branch. Even with Purgatorius removed, the crown primates may even have emerged in this group.
The Fort Union Formation is a geologic unit containing sandstones, shales, and coal beds in Wyoming, Montana, and parts of adjacent states. In the Powder River Basin, it contains important economic deposits of coal, uranium, and coalbed methane.
Lycophocyon is an extinct genus of caniformian carnivoran from Middle Eocene deposits of San Diego County, California. Lycophocyon is known from the holotype UCMP 85202, a partial left and right dentary. Paratypes include UCMP 170713, SDSNH 107658, SDSNH 107659, SDSNH 107442, SDSNH 107443 and SDSNH 107444, partial dentaries, mandibles and other cranial remains, and SDSNH 107446 and SDSNH 107447, cranial and postcranial fragments. Many additional specimens are also known. All specimens were collected from numerous localities, all of them from the upper portions of "member C" of the Santiago Formation. It was first named by Susumu Tomiya in 2011 and the type species is Lycophocyon hutchisoni. The generic name means "twilight dog" in Greek, in references to its occurrence on the west coast of North America, and its affinity to the Caniformia. The specific name honours the paleontologist J. Howard Hutchison.
This paleomammalogy list records new fossil mammal taxa that were described during the year 2012, as well as notes other significant paleomammalogy discoveries and events which occurred during that year.
The Willwood Formation is a sedimentary sequence deposited during the late Paleocene to early Eocene, or Clarkforkian, Wasatchian and Bridgerian in the NALMA classification.
This paleomammalogy list records new fossil mammal taxa that were described during the year 2013, as well as notes other significant paleomammalogy discoveries and events which occurred during that year.
This paleomammalogy list records new fossil mammal taxa that were described during the year 2014, as well as notes other significant paleomammalogy discoveries and events which occurred during that year.
The Washakie Formation is a geologic formation in northern Colorado and southern Wyoming. It preserves many mammal, bird, reptile and other fossils dating back to the Lutetian stage of the Eocene within the Paleogene period. The sediments fall in the Bridgerian and Uintan stages of the NALMA classification.
The Mission Valley Formation is a marine sandstone geologic formation in the Mission Valley region of southwestern San Diego County, California.
The Pomerado Conglomerate Formation is a geologic formation in southwestern San Diego County, California.
The Atotonilco El Grande Formation is a geologic formation in Mexico. It preserves fossils dating back to the Neogene period.
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This paleomammalogy list records new fossil mammal taxa that were described during the year 2011, as well as notes other significant paleomammalogy discoveries and events which occurred during that year.
Microsyops is a plesiadapiform primate found in Middle Eocene in North America. It is in the family Microsyopidae, a plesiadapiform family characterized by distinctive lanceolate lower first incisors. It appears to have had a more developed sense of smell than other early primates. It is believed to have eaten fruit, and its fossils show the oldest known dental cavities in a mammal.
Machaeroidinae ("dagger-like") is an extinct subfamily of carnivorous sabre-toothed placental mammals from extinct family Oxyaenidae, that lived from the early to middle Eocene of Asia and North America. Traditionally classified as hyaenodonts, this group is now classified as a member of the family Oxyaenidae.
Altacreodus is an extinct genus of eutherian mammals. Fossils have been found in North America where they first appeared during the Late Cretaceous, and they died out prior to the start of the Paleocene. It is possibly one of the earliest known placental mammals in the fossil record.
Ignacius is a genus of extinct mammal from the early Cenozoic era. This genus is present in the fossil record from around 62-33 Ma. The earliest known specimens of Ignacius come from the Torrejonian of the Fort Union Formation, Wyoming and the most recent known specimens from Ellesmere Island in northern Canada. Ignacius is one of ten genera within the family Paromomyidae, the longest living family of any plesiadapiforms, persisting for around 30 Ma during the Paleocene and Eocene epochs. The analyses of postcranial fossils by paleontologists suggest that members of the family Paromomyidae, including the genus Ignacius, most likely possessed adaptations for arboreality.
Nyctitheriidae is a family of extinct eulipotyphlan insectivores known from the Paleocene and Eocene epochs of North America and Asia and persisting into the Oligocene of Europe. Several genera, including Nyctitherium, Paradoxonycteris, and Wyonycteris, have initially been described as bats, although the family is more frequently placed in the order Eulipotyphla.