Age. Mid and Late Wisconsin (Holocene material also has been recovered, but is not addressed here). O'Keefe et al. (2009) assembled 209 radiocarbon dates from the various pits and discussed these at length. Dates range from the present to more than 50,000 years.
General Description (Stock and Harris 1992). Rancho la Brea is located within the city of Los Angeles. Hydrocarbons from pre-Pleistocene sediments rose into the Pleistocene sediments, forming pools of asphalt as the more volatile elements evaporated. Pools of viscus liquid asphalt formed natural traps. The large number of carnivores represented in the fossil deposits suggest that trapped animals attracted predators and scavengers that, in turn, also became trapped. As of 1992, more than 2,000,000 bones, along with numerous remains of insect, mollusks, and plants, have been recovered. Excavations continue to the present.
Woodard and Marcus (1973) note that asphaltic activity was sporadic within pits rather than continuous. They also stressed that fluvial sedimentation was ongoing during the time span involved and played a part in movement and concentration of bones.
Fauna.
Oncorhynchus mykiss—Rainbow Trout (Swift 1989)
Gila orcutti—Arroyo Chub (Swift 1989)
Gasterosteus aculeatus—Three-spined Stickleback (Swift 1989)
Aneides lugubris—Arboreal Salamander (Stock and Harris 1992)
Anaxyrus boreas—Western Toad (Brattstrom 1953; Tihen 1962)
Camp (1917) described a new fossil species, Bufo nestor, from Rancho la Brea. Tihen (1962) considered this to be a synonym of Bufo boreas. The genus Bufo has since been restricted to the eastern hemisphere (Frost et al. 2006), with the next available name being Anaxyrus.
Anaxyrus microscaphus—Arizona Toad (Stock and Harris 1992)
Bufo microscaphus
Hyla sp.—Treefrogs (Brattstrom 1953)
Rana aurora—Northern Red-legged Frog (Brattstrom 1953)
Actinemys pallida—Southern Western Pond Turtle (Brattstrom 1953)
Clemmys marmorata
†Hesperotestudo sp.—Hesperotestudo Tortoises (Jefferson 2014: cf.)
Geochelone ?
Although the list of lizards given below follows the earlier literature, Bell and Dundas (1993) are skeptical at the identification levels given. They specifically clump the phrynosomatid taxa as "Sceloporine, gen. and sp. indet.", the teiid taxon (Aspidoscelis tigris in the list below) as only identifiable at the generic level (and that based in part on geography), and the skink to genus only.
Elgaria multicarinatus—Southern Alligator Lizard (Brattstrom 1953) Gerrhonotus multicarinatus Anniella sp.—North American Legless Lizards (Jefferson 2014) Phrynosoma coronatum Sceloporus magister—Desert Spiny Lizard (Brattstrom 1953) Eumeces Aspidoscelis tigris—Western Whiptail(Brattstrom 1953) Cnemidophorus tigris Xantusia vigilis—Desert Night Lizard (Brattstrom 1953) Disallowed Heche (1956) noted that no species of the genus Xantusia had the tooth characteristics described by Brattstrom and that the specimen turns out to belong to a different family. |
Arizona elegans—Glossy Snake (LaDuke 1991) Lampropeltis getulus Masticophis lateralis—Striped Racer (LaDuke 1991) Pituophis melanoleucus Rhinocheilus lecontei—Long-nosed Snake (LaDuke 1991) Hypsiglena torquata of LaDuke (1991). Mulcahy (2008) split H. torquata into several species, including H. ochrorhyncha, indicated as occurring currently in southwestern California. This taxonomy is not recognized by all. The assumption here is that the fossil form is the same as that now in the region. Thamnophis couchii complex—Sierra Gartersnake complex (LaDuke 1991) |
†Anabernicula gracilenta—Graceful Pygmy Goose (Stock and Harris 1992) Casmarodius albus Ardea herodias—Great Blue Heron (Stock and Harris 1992) Ajaia ajaja †Cathartornis gracilis—Slender Teratorn (Stock and Harris 1992) Gymnogyps amplus (see G. californianus for usage) Accipiter gentilis—Northern Goshawk (Stock and Harris 1992) Wetmoregyps daggetti †Buteogallus fragilis—Fragile Black-hawk (Stock and Harris 1992) Catoptrophorus semipalmatus Charadrius vociferus—Killdeer (Stock and Harris 1992) Gallinago gallinago delicata Limnodromus griseus—Short-billed Dowitcher (Stock and Harris 1992) Columba fasciata |
Zenaida macroura—Mourning Dove (Stock and Harris 1992) Earlier identifications as Aegolius acadicus (e.g., Stock and Harris 1992) apply to Asphaltoglaux. Athene cunicularia—(Burrowing Owl (Stock and Harris 1992) Specimens earlier referred to Glaucidium gnoma have been reidentified as the present species. Megascops asio—Eastern Screech-Owl (Stock and Harris 1992) Otus asio †Oraristrix brea—Tar-pit Owl (Campbell and Bocheński 2010) Colaptes auratus cafer Dryocopus pileatus—Pileated Woodpecker (Stock and Harris 1992) Polyborus plancus Falco columbarius—Merlin (Stock and Harris 1992) Aphelocoma coerulescens, Aphelocoma coerulescens californica Corvus brachyrhynchos—American Crow (Stock and Harris 1992) Parus sp. cf. P. gambeli Sialia mexicana—Western Bluebird (Stock and Harris 1992: cf.) Amphispiza belli Chondestes grammacus—Lark Sparrow (Stock and Harris 1992) Pipilo fuscus Passerella iliaca—Fox Sparrow (Stock and Harris 1992) Pipilo erythrophthalmus; P. erythrophthalmus has been split into eastern and western species. Presumably the Rancho La Brea species is P. maculatus. †Pipilo angelensis—Los Angeles Towhee (Stock and Harris 1992) Carduelis pinus Spinus tristis—American Goldfinch (Stock and Harris 1992) Carduelis tristis |
†Mammuthus columbi—Columbian Mammoth (Stock and Harris 1992) Glossotherium harlani Otospermophilus beecheyi—California Ground Squirrel (Stock and Harris 1992) Spermophilus (Otospermophilus) beecheyi Tamias merriami—Merriam's Chipmunk (Whistler 1989: cf.) Perognathus californicus Thomomys bottae—Botta's Pocket Gopher (Stock and Harris 1992) |
Puma concolor—Mountain Lion (Stock and Harris 1992) Felis concolor Lynx rufus—Bobcat (Stock and Harris 1992) Also listed: Smilodon fatalis brevipes †Canis dirus—Dire Wolf (Stock and Harris 1992) It's assumed here that this record is Holocene and is not treated further. Canis latrans—Coyote (Stock and Harris 1992) Spilogale putorius Bassariscus astutus—Ringtail (Akersten et al. 1979)[Pit A] (Stock and Harris 1992) Capromeryx minor †Bison antiquus—Ancient Bison (Stock and Harris 1992) |
Literature Akersten et al. 1979; Bell and Dundas 1993; Bocheński and Campbell 2006; Brattstrom 1953;Camp 1917; Campbell 1995; Campbell and Bocheński 2010; Campbell and Bocheński 2013; Dooley et al. 2019; Hecht 1956; Howard 1933; Jefferson 2014; LaDuke 1991; L. Miller 1909; Mulcahy 2008; O'Keefee et al. 2009; Stock and Harris 1992; Swift 1989; Tihen 1962; Whistler 1989; Woodard and Marcus 1973.
Last Update: 6 Apr 2019