MIRED AND RETIRED: AGE-SELECTIVE COLUMBIAN MAMMOTH (MAMMUTHUS COLUMBI) MORTALITY FROM RANCHO LA BREA, CALIFORNIA AND ITS IMPLICATIONS FOR EVALUATING TOP-DOWN FORCING IN LATE PLEISTOCENE TROPHIC SYSTEMS

2020 ◽  
Author(s):  
Lauren E. Parry ◽  
◽  
Stephen M. Rowland ◽  
Stephen M. Rowland
Keyword(s):  
Late Pleistocene ◽  
Top Down ◽  
Rancho La Brea

STABILITY OF DENTAL MESOWEAR SCORES THROUGHOUT THE LATE PLEISTOCENE IN LARGE UNGULATES FROM RANCHO LA BREA

2019 ◽  
Author(s):  
Joshua E. Cohen ◽  
◽  
Larisa R.G. DeSantis ◽  
Emily Lindsey ◽  
Julie Meachen ◽  
...  
Keyword(s):  
Late Pleistocene ◽  
Rancho La Brea

New Source of Dietary Data for Extinct Herbivores

1988 ◽  
Vol 30 (1) ◽  
pp. 92-97 ◽  
Author(s):  
William A. Akersten ◽  
Theresea M. Foppe ◽  
George T. Jefferson
Keyword(s):  
Late Pleistocene ◽  
Indirect Evidence ◽  
Bison Bison ◽  
Large Herbivores ◽  
Usual Assumption ◽  
Microhistological Analysis ◽  
Rancho La Brea ◽  
Very High ◽  
Control Study ◽  
Dietary Data

The teeth of many large herbivores contain “pockets” (fossettes, fossettids, etc.) which entrap impacted samples of food (dental boluses) during mastication. These do not preserve well in most fossil deposits, but at Rancho La Brea, paleobotanical remains survive essentially intact and dental boluses from late Pleistocene forms are amenable to microhistological analysis. Of the identifiable bolus contents, those from Bison antiquus averaged 87% nonmonocotyledons; from Camelops hesternus, 90% nonmonocotyledons; and from Equus occidentalis (one specimen), 56% nonmonocotyledons. A control study on modern Bison bison shows that the boluses contain somewhat lower percentages of monocotyledons than do alimentary samples from the same individuals. However, this accounts for only a part of the very high percentage of nonmonocotyledons in the boluses of the extinct Bison. We conclude that the populations of B. antiquus and C. hesternus represented at Rancho La Brea probably fed little on grasses and that there is enough indirect evidence to suggest that the same may be true for other populations of these taxa. The Equus data are not sufficient to do more than question the usual assumption that Pleistocene horses were always obligate grass eaters.

Seasonal Migration of Bison Antiquus from Rancho La Brea, California

1989 ◽  
Vol 31 (1) ◽  
pp. 107-112 ◽  
Author(s):  
George T. Jefferson ◽  
Judith L. Goldin
Keyword(s):  
Young Adult ◽  
Late Pleistocene ◽  
Annual Cycle ◽  
Reproductive Behavior ◽  
Seasonal Migration ◽  
Occlusal Wear ◽  
Migratory Pattern ◽  
Bison Antiquus ◽  
First Time ◽  
Rancho La Brea

AbstractEvidence for annual seasonal migration of extinct Bison antiquus in the late Pleistocene fossil assemblage from Rancho La Brea, California, is demonstrated for the first time. The maturation of individuals from the B. antiquus sample was analyzed using the cheek tooth eruption sequence and occlusal wear patterns in juvenile and young adult inferior dentitions. Individual age of the specimens was established by comparison with wear stages observed in modern B. bison dentitions of known age. Assuming that reproductive behavior was restricted to a specific annual cycle similar to modern B. bison, B. antiquus was seasonally present at Rancho La Brea during the late spring. An annual migratory pattern is indicated by the presence in the assemblage of yearly groups of young individuals of the same age.

Late Quaternary Insects of Rancho La Brea and McKittrick, California

1983 ◽  
Vol 20 (1) ◽  
pp. 90-104 ◽  
Author(s):  
Scott E. Miller
Keyword(s):  
Los Angeles ◽  
Late Pleistocene ◽  
Los Angeles County ◽  
Late Quaternary ◽  
Dung Beetles ◽  
Kern County ◽  
Vertebrate Fauna ◽  
Modern Species ◽  
Terminal Pleistocene ◽  
Rancho La Brea

AbstractAsphalt-impregnated sediments at Rancho La Brea (Los Angeles County) and McKittrick (Kern County) in California provide a rich Quaternary insect record. Ages of various sites at Rancho La Brea range from more than 40,000 14C yr B.P. to modern. McKittrick insects studied by W. D. Pierce are not contemporaneous with the late Pleistocene vertebrate fauna, but are only about 7000 14C yr old. The major paleoecological groupings are: (1) ground dwellers, (2) aquatics. (3) scavengers, and (4) miscellaneous. Contrary to conclusions of earlier authors, most specimens represent modern species. Only two apparent terminal Pleistocene extinctions are recognized. both dung beetles (Scarabaeidae).

Late Pleistocene shrub expansion preceded megafauna turnover and extinctions in eastern Beringia

2021 ◽  
Vol 118 (52) ◽  
pp. e2107977118
Author(s):  
Alistair J. Monteath ◽  
Benjamin V. Gaglioti ◽  
Mary E. Edwards ◽  
Duane Froese
Keyword(s):  
Late Pleistocene ◽  
Keystone Species ◽  
Plant Macrofossils ◽  
Shrub Expansion ◽  
Top Down ◽  
Tundra Vegetation ◽  
Shrub Tundra ◽  
Postglacial Expansion ◽  
Sediment Layers ◽  
Mammal Communities

The collapse of the steppe-tundra biome (mammoth steppe) at the end of the Pleistocene is used as an important example of top-down ecosystem cascades, where human hunting of keystone species led to profound changes in vegetation across high latitudes in the Northern Hemisphere. Alternatively, it is argued that this biome transformation occurred through a bottom-up process, where climate-driven expansion of shrub tundra (Betula, Salix spp.) replaced the steppe-tundra vegetation that grazing megafauna taxa relied on. In eastern Beringia, these differing hypotheses remain largely untested, in part because the precise timing and spatial pattern of Late Pleistocene shrub expansion remains poorly resolved. This uncertainty is caused by chronological ambiguity in many lake sediment records, which typically rely on radiocarbon (14C) dates from bulk sediment or aquatic macrofossils—materials that are known to overestimate the age of sediment layers. Here, we reexamine Late Pleistocene pollen records for which 14C dating of terrestrial macrofossils is available and augment these data with 14C dates from arctic ground-squirrel middens and plant macrofossils. Comparing these paleovegetation data with a database of published 14C dates from megafauna remains, we find the postglacial expansion of shrub tundra preceded the regional extinctions of horse (Equus spp.) and mammoth (Mammuthus primigenius) and began during a period when the frequency of 14C dates indicates large grazers were abundant. These results are not consistent with a model of top-down ecosystem cascades and support the hypothesis that climate-driven habitat loss preceded and contributed to turnover in mammal communities.

scholarly journals The dynamic coastal evidence of Jakarta Bay during Late Pleistocene-Recent

2021 ◽  
Vol 930 (1) ◽  
pp. 012002
Author(s):  
F Novico ◽  
C Endyana ◽  
D Menier ◽  
M Mathew ◽  
I Kurniawan ◽  
...  
Keyword(s):  
Sea Level ◽  
Late Pleistocene ◽  
Climatic Variability ◽  
Line Drawing ◽  
Sea Level Changes ◽  
Top Down ◽  
Seismic Records ◽  
Coastal Dynamic ◽  
Map Series ◽  
Seismic Reflectors

Abstract Some significant indication identifying a coastal dynamic during Late Pleistocene to Recent is the evolution of isochrone patterns throughout glacial-interglacial stages. This study aims to identify the sediments stratification of Jakarta Bay during the Late Pleistocene – Recent in the framework of coastal dynamic triggered by the sea-level changes of last prominent climatic stages. The several high-resolution seismic records in Jakarta Bay lines were interpreted to illustrate the different sequences from the top down to the oldest by line-drawing the more robust seismic reflectors as a sequence limit surface. Furthermore, the isochrone map series of unit boundary (UB) were reconstructed to delineate isochrone contour patterns from the oldest until modern. The selected isochrones map of UB-3 and UB-5 with their unit facies are somehow favorable to be compared for observing the coastal dynamic of Jakarta Bay during the last climatic variability. Finally, the coastal dynamic of Jakarta Bay is discovered by the movement series of isochrones contour patterns that correspond to the sea-level changes during the last prominent glacial-interglacial stages.

Size and shape stasis in late Pleistocene mammals and birds from Rancho La Brea during the Last Glacial–Interglacial cycle

2012 ◽  
Vol 56 ◽  
pp. 1-10 ◽  
Author(s):  
Donald R. Prothero ◽  
Valerie J. Syverson ◽  
Kristina R. Raymond ◽  
Meena Madan ◽  
Sarah Molina ◽  
...  
Keyword(s):  
Late Pleistocene ◽  
Size And Shape ◽  
Last Glacial ◽  
Pleistocene Mammals ◽  
Rancho La Brea ◽  
The Last Glacial

The fossil avifauna of the tar seeps Las Breas de San Felipe, Matanzas, Cuba

Zootaxa ◽  
2020 ◽  
Vol 4780 (1) ◽  
pp. 1-53 ◽  
Author(s):  
WILLIAM SUÁREZ
Keyword(s):  
Late Pleistocene ◽  
New World ◽  
Bird Species ◽  
Fossil Birds ◽  
American Continent ◽  
Present Contribution ◽  
Ecological Preferences ◽  
First Time ◽  
Rancho La Brea

The Cuban fossil avifauna, prior to this study, included 30 extinct and extirpated valid taxa. In the present contribution, we review the fossil avifauna from Las Breas de San Felipe, and in so doing increase the diversity of Cuban fossil birds to 36 species with the description of a New World vulture, Coragyps seductus sp. nov., three accipitrids, Gigantohierax itchei sp. nov., Buteogallus royi sp. nov., and Buteo sanfelipensis sp. nov., a small caracara, Milvago diazfrancoi sp. nov., plus Buteogallus cf. B. fragilis (L. Miller, 1911), which is recorded for the first time in Cuba and the Antillean Subregion. Of the total of 34 bird species now registered from Las Breas de San Felipe, 21 (61.8 %) are extinct and 13 (38.2 %) correspond to species that still live in Cuba, other Antillean islands, or in the American continent. Raptors dominate the assemblage, with 26 (76.5 %) species. These are mostly from Accipitridae and Falconidae, and 19 (55.9 %) are diurnal and 7 (20.6 %) nocturnal. This abundance of raptors in Las Breas de San Felipe is similar to the composition from other asphalt deposits known from the American continent such as Rancho La Brea. The palaeoavifauna from this locality can be split, according to ecological preferences, into three groups or guilds. Radiocarbon (14C) dates indicate a late Pleistocene age for some of the recovered bird remains, including those of Antigone cubensis (Fischer & Stephan, 1971) comb. nov., Gymnogyps varonai (Arredondo, 1971) and Ornimegalonyx oteroi (Arredondo, 1958). 

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