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Class Mammalia
Order Proboscidea
Family Mammutidae


Mammut sp.—MastodonsPleistocene distribution of Mammut sp.

Based on currently known distributions, all of the occurrences listed below, with the sole exception of El Fin del Mundo, likely represent the recently recognized species, Mammut pacificus (Dooley et al. 2019)


Rancholabrean: Beverly Hills (Jefferson 1991b); Black Butte (Jefferson 1991b: ? gen.); Camarillo (Jefferson 1991b); Corona, California (Jefferson 1991b); El Fin del Mundo (Sanchez et al. 2009); Fourth and Mesa streets, San Pedro (Jefferson 1991b); Gaviota Pass (Jefferson 1991b); Hicks Canyon (Jefferson 2014); Manchester and Airport boulevards (Jefferson 1991b: ? gen.); Manning Rock, Irwindale (Jefferson 1991b); Outfall Sewer, Rodeo and Kelley, Culver City (Jefferson 1991b); Point Sal (Jefferson 1991b); Rubidoux (Jefferson 1991b); Salt Creek, California (Jefferson 1991b); San Buenaventura (Jefferson 1991b); Santa Susana Pass, north of Chattsworth (Jefferson 1991b); Tijuana River Valley (Jefferson 1991b); Tremaine and 8th streets (Jefferson 1991b).

Mid/Late Wisconsin: Glendale (Jefferson et al. 2015).

Late Wisconsin: Dove Springs Megafauna Loc. (Jefferson 2014: cf.); Maricopa (Jefferson 1991b).

Literature. Jefferson 1991b, 2014; Jefferson et al. 2015; Sanchez et al. 2009.


Mammut americanum (Kerr 1791)—American MastodonPleistocene distribution of Mammut americanum

Three families of proboscideans are represented in the Pleistocene of the region. Mastodons have relatively simple cheek teeth, suggesting that they were browsers on soft vegetation. Stomach contents from elsewhere in North America bear this up, with conifers making up a fair amount of the diet.

Although common during the Pleistocene in the northern parts of the continent, mastodons are relatively uncommon in the inland West and Southwest. Extinction apparently occurred concurrently with other megafaunal taxa. Fiedel (2009) gives a number of dates seemingly marking the last survivors and ranging from 11,720 ± 110 to 10,395 ± 100 BP.

Fossil Mammut americanum, Museum of the Earth

Fig. 1. Mastodon skeleton, Museum of the Earth. This file is licensed under Creative Commons Attribution ShareAlike 2.0 License. This image was originally posted to Flickr by bronayur at


Pleistocene: Lemitar (Morgan and Lucas 2005); Los Lunas (Morgan and Lucas 2005); Piñon (Morgan and Lucas 2005); Rancho Creek (Wheeler 1875); Trapped Rock Draw (Morgan and Lucas 2005); Tree Spring, Sandia Mts. (Morgan and Lucas 2005).

Irvingtonian: El Paso (East of El Paso, Personal Observation; N Bowie Mastodont Site (Pasenko 2012); Northeast El Paso (UTEP).

Early Rancholabrean: Albuquerque Gravel Pits (Morgan and Lucas 2005);.

Rancholabrean: Jal (Schultz 1943); < Placitas (Hibben 1941; Morgan and Lucas 2005).

Wisconsin: ; Lehner Site (Mead et al. 1979).

Late Wisconsin: Billings (Minckley et al. 1997); Cerros Negros (Agenbroad et al. 2013); Davidson Canyon (Pasenko 2011); La Mirada (Jefferson 1991b); Leupp (Minckley et al. 1997); M & M Mastodon (Pasenko 2011); Placitas (Hibben 1941); Saint Johns (Agenbroad et al. 2013); Sandia Cave, Sandia Level (Hibben 1941; Morgan and Lucas 1997).

Literature. Agenbroad et al. 2013; Fiedel 2009; Hibben 1941; Jefferson 1991a, 1991b, 2014; Lucas and Morgan 1997; Mead et al. 1979; Minckley et al 1997; Morgan and Lucas 2005; Pasenko 2011, 2012; Schultz 1937, 1943; Springer et al. 2009; Stock and Harris 1992; Wheeler 1875.


Mammut pacificus Dooley, Scott, Green, Springer, Dooley, and Smith 2019—Pacific MastodonPleistocene regional distribution of Mammut pacificus

Recent investigation of fossil mastodons has resulted in the recognition that North American mastodons consist of two species rather than being monospecific. Dooley et al.(2019:6) give the following diagnosis: "A species of Mammut differing from Mammut americanum in the following characteristics: M3/m3 significantly narrower relative to length; six fused sacral vertebrae in later ontogenetic stages (usually five in M. americanum, with a range of four to six); femur with a greater midshaft diameter relative to length; absence of mandibular tusks and associated alveoli (variably present in M. americanum); smaller basal diameter of tusks in males for a given age.

Specimen localities that have not appeared here in earlier versions have only Dooley et al. cited; Californian specimens previously identified as M. americanum are assumed here to be M. pacifius and Dooley et al. and the author who earlier cited the locality are both cited. Localities cited by Jefferson 1991b as M. americanus and from Los Angeles County are underlined and listed first.


Irvingtonian: Murieta (Dooley et al. 2019).

?Irvingtonian/Rancholabrean: Emery Borrow Pit (Jefferson 1991b).

Rancholabrean: Beverly Blvd. and Kilkea Drive (Jefferson 1991b); Consolidated Rock Co., Alameda St. near 26th St. (Jefferson 1991b); Cypress and Slauson avenues, Hyde Park (Jefferson 1991b); u>La Cienega Blvd. near Colgate Ave. (Jefferson 1991b); Los Angeles Brick Yard No. 3 (Jefferson 1991b); Metro Rail Hollywood Tunnel (Jefferson 2014); National City West (Jefferson 2014);Armitage Heights (Dooley et al. 2019); Carpinteria (Dooley et al. 2019); Carrizo Plain (Dooley et al. 2019; Jefferson 1991b); Arbogast Ranch (Jefferson 1991b); Chorro Creek (Dooley et al. 2019; Jefferson 1991b); Copper Canyon, Murieta (Dooley et al. 2019); Imperial Highway (Jefferson 1991b); Jurupa Valley (Dooley et al. 2019); Lakes at Thousand Oaks Shopping Center (Dooley et al. 2019; McKittrick (Dooley et al. 2019; Schultz 1937); Perris (Dooley et al. 2019); Rancho la Brea (Dooley et al. 2019; Robertson Ranch (Dooley et al. 2019; Jefferson 2014); Santa Barbara Co. (Dooley et al. 2019); Sima Valley (Dooley et al. 2019);Solano Beach (Jefferson 1991b); Sun Valley (Dooley et al. 2019); Wanis View (Dooley et al. 2019; Jefferson 2014)

Sangamon: Chandler Sand Pit, Rolling Hills Estates (Jefferson 1991b); Newport Bay Mesa (Jefferson 1991b).

Mid/Late Wisconsin: Diamond Valley (Dooley et al. 2019; Springer et al. 2009); Rancho La Brea (Stock and Harris 1992).

Literature. Dooley et al. 2019; Jefferson 1991b.

Last Update: 29 May 2015