Name: Rancho La Brea.
Location: Los Angeles, California.

Age: 38,000 years old to recent.

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Fauna and Flora of Rancho La Brea


Figure 1. The Carnivore guild of Rancho La Brea.

From left to right.  The dire wolf (Canis dirus), the sabre-toothed cat (Smilodon fatalis), the short-faced bear (Arctodus simus), the cheetah-like cat (Miracinonyx sp.), and the American lion (Panthera leo atrox). (modified from Turner and Anton, 1997).

Figure 2. The Herbivore guild of Rancho La Brea.

From left to right.  The pronghorn (Antilocapra americana), the deer (Odocoileus sp.), the giant camel (Camelops hesternus), the horse (Equus occidentalis), and the bison (Bison sp.).

(modified from Turner and Anton, 1997).

 

Faunal List of the mammals of Rancho La Brea.

Order Insectivora (Shrews and moles)

Sorex cf. ornatus- Ornate shrew.

Notiosorex crawfordi- Desert shrew.

Scapanus latimanus- Broad-handed mole.

Order Primates

Homo sapiens- Man.

Order Chiroptera (Bats)

Lasiurus cinereus- Hoary bat.

Order Edentata (Sloths, armadillos, glyptodons)

*Nothrotheriops shastensis- Shasta ground sloth.

*Megalonyx jeffersoni- Jefferson’s gound sloth.

*Glossotherium harlani- Harlan’s ground sloth.

Order Rodentia (Squirrels, rats, mice)

Citellus variegatus- Rock squirrel.

Thomomys bottae- Valley pocket gopher.

Perognathus californicus- California pocket mouse.

Dipodomys agilis- Pacific kangaroo rat.

Reithrodontomys megalotis- Western harvest mouse.

*Peromyscus imperfectus- Imperfect mouse.

Onychomys torridus- Southwestern grasshopper mouse.

Microtus californicus- California vole.

Spermophilus beecheyi- California ground squirrel.

Neotoma fuscipes- Dusky-footed wood rat.

Tamias merriami- Merriam’s chipmunk.

Order Carnivora (Wolves, bears, raccoons, cats)

Canis latrans- Coyote.

Canis lupus- Timber wolf.

*Canis dirus- Dire wolf.

Canis familiaris- Domestic dog.

Urocyon cinereoargenteus- Grey fox.

*Arctodus simus- Short-faced bear.

Ursus americanus- Black bear.

Ursus arctos- Brown bear.

Mustela frenata- long-tailed weasel.

Taxidea taxus- American badger.

Spilogale putorius- Southwestern spotted skunk.

Mephitis mephitis- Striped skunk.

*Felis daggetti- Daggett cat.

Puma concolor- Cougar.

*Panthera leo atrox- American lion.

Lynx rufus- Bobcat.

*Smilodon fatalis- Sabre-toothed cat.

*Homotherium serum- Scimitar-toothed cat.

*Miracinonyx sp.- Cheetah-like cat.

Order Proboscidea (Mastodons and Mammoths)

*Mammut americanum- American mastodon.

*Mammuthus imperator- Imperial mammoth.

*Mammuthus columbi- Columbian mammoth.

Order Lagomorpha (Rabbits and Hares)

Lepus californicus- Blacktail jackrabbit.

Sylvilagus audubonii- Desert cottontail.

Sylvilagus bachmani- Brush rabbit.

Order Artiodactyla (Even toed ungulates)

*Platygonus compressus- LeConte’s peccary.

*Camelops hesternus- Western camel.

*Breameryx minor- Tar-pit pronghorn.

Antilocapra americana- Pronghorn.

*Bison antiquus- Ancient Bison.

*Hemiauchenia macrophala- Stilt-legged llama.

Cervus elephas- Wapiti.

Order Perissodactyla (Odd toed ungulates)

*Tapirus californicus- Extinct tapir.

*Equus occidentalis- Western horse.

*Equus conversidens- Small stout-limbed horse.

*=extinct form.

Table 1. List of mammals from Rancho la Brea. For a fuller list of all organisms present in the La Brea tarpits see Stock and Harris (1992) (modified from Harris, 1985; Flint, R.F.; and Stock and Harris, 1992).

Fauna:

The assemblage from the La Brea tarpits is generally similar to that of the present Californian area except for those animals that are now extinct. However, as noted by several key workers, the disproportionate representation of carnivores, which make up nearly 90% of all individuals found is exceedingly strange in comparison to extant ecosystems. The Dire wolf (Canis dirus) is the most common animal with the sabre-toothed cat (Smilodon fatalis) and the coyote (Canis latrans) running it a close second.

Except for the mammals, the other common vertebrates are the birds. These include representatives of the Podicipediformes, Pelecaniformes, Ardeiformes, Anseriformes, Ciconiiformes, Accipitriformes, Galliformes, Gruiformes, Charadriiformes, Columbiformes, Cuculiformes, Strigiformes, Caprimulgiformes, Piciformes, and Passeriformes. Two orders of reptiles are present the Testudinata and Squamata, together with frogs and salamanders. Lastly, three orders of fishes are present: Salmoniformes, Cypriniformes, and Gasterosteiformes.

Several invertebrates are known from the deposits but these are noted only in most general terms. The Arthropods present are members of Arachnida, Crustacea, Diplopoda, Chilopoda, and Insecta. Also, present two classes of Molluscs, the Bivalvia, and Gastropoda.

Flora:

There are a number of plant communities represented in the La Brea tar pits. There are representatives of a pine forest with associated Monterey Cypress, which would have flourished in the cool humid conditions of the coastline. A coastline redwood element with Sequoia also existed, together with an inland dry foothill plant community. A shallow freshwater pond assemblage together with a stream bank community and a drier grassland assemblage are also represented. This large assemblage is interpreted is as the result of transport of plant debris from streams flowing through many different local environments.

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