干旱区生态环境知识资源中心(Arid): Paleoenvironments and paleoecology of the Santa Cruz Formation (early-middle Miocene) along the Rio Santa Cruz, Patagonia (Argentina)

Arid

DOI	10.1016/j.jsames.2021.103296
	Paleoenvironments and paleoecology of the Santa Cruz Formation (early-middle Miocene) along the Rio Santa Cruz, Patagonia (Argentina)
	Kay, Richard F.; Vizcaino, Sergio F.; Susana Bargo, M.; Spradley, Jackson P.; Cuitino, Jose, I
通讯作者	Kay, RF (corresponding author), Duke Univ, Dept Evolutionary Anthropol, Durham, NC 27708 USA. ; Kay, RF (corresponding author), Duke Univ, Div Earth & Ocean Sci, Durham, NC 27708 USA.
来源期刊	JOURNAL OF SOUTH AMERICAN EARTH SCIENCES
ISSN	0895-9811
EISSN	1873-0647
出版年	2021
卷号	109
英文摘要	The continental early-middle Miocene Santa Cruz Formation (SCF) in Austral Patagonia contains the best record of South American mammalian faunas prior to the Great American Biotic Interchange (GABI) and is of particular interest because it is the best preserved high-latitude continental biotic record in the Southern Hemisphere spanning the mid-Miocene Climatic Optimum. Through intensive fieldwork we recovered numerous fossil vertebrates, mostly mammals, from the SCF along the Rio Santa Cruz (RSC), the type area for the formation and its fauna. We examine whether the SCF fauna differed among three distinct temporal intervals of the SCF spanning, from the oldest to youngest, the Atlantic coastal suite of localities Fossil Levels (FL) 1-7, at about 17.4 Ma, through localities in the RSC Barrancas Blancas (BB), between similar to 17.2 and similar to 16.3 Ma, and Segundas Barrancas Blancas (SBB), between similar to 16.5 and similar to 15.6 Ma. With the objective of reconstructing paleoenvironmental and community structure of these RSC faunas, we compared them with 55 extant lowland mammalian localities across South America from 8 degrees N to 55 degrees S latitude representing a wide range of seasonality and, annual rainfall and temperature, as well as canopy height and net primary productivity, sampling communities ranging from tropical rainforest to semi-arid steppe. Extant nonvolant mammalian genera at each locality were assigned a body size interval and niche parameters reflecting diet and substrate use, from behavioral data in the literature. Extinct genera were assigned similar niche metrics on the basis of their morphology. From the generic niche parameters, we compiled indices and ratios that express vectors of the community structure of each fauna, including the total number of genera, the pervasiveness of arboreality, frugivory, and browsing, and the relative richness of predators to their prey. The community structure variables were used to model community structure of the fossil localities based on uniformitarian principles. The fossil sample includes 44 genera of mammals from FL 1-7, 38 genera from BB, and 44 genera from SBB. The Simpson Coefficients of faunal similarity among the fossil localities are no greater than expected on the basis of the geographic distances among them, and do not suggest any apparent climatic differences. Based on the models we obtained no significant differences in MAP (Mean Annual Precipitation) for FL 1-7, BB and SBB, with mean estimates of 1635 mm, 1451 mm, and 1504 mm, with the confidence intervals for the estimates overlapping widely. MAT (Mean Annual Temperature) estimates are between similar to 21 degrees C and similar to 22 degrees C for FL 1-7 and SBB, possibly lower at 16 degrees C for BB, but with a wide and overlapping range of estimates. Temperature seasonality is modest (3 degrees C to 4 degrees C) and similar for all localities. Canopy heights exceed 20 m for all sites. Despite these geographic and inferred climatic similarities, the presence of certain key taxa (e.g., the caviomorph rodent Prolagostomus and the typothere Pachyrukhos) together with an increased overall abundance and richness of rodents with ever-growing cheek teeth suggests a trend to aridification in the upper part of the SCF at SBB compared with FL 1-7 and BB. Taken together, we propose that the SCF paleoenvironment consisted largely of semi-deciduous forests ranging into savannas with gallery-forest components. This range of habitats occurs today where the mesic inland Atlantic forests of Southern Brazil, northeastern Argentina and eastern Paraguay give way northwestward into the more xeric Paraguayan Gran Chaco. These interpretations are in general agreement with other sources of evidence from sedimentology, paleosols, isotopes, paleobotany and other faunal elements. We highlight the value of focusing paleoenvironmental and paleocological studies of the SFC on stratigraphically and geographically confined samples instead of on the entire temporal and geographic distribution of the SCF based on historical collections with limited provenance. The Santacrucian can be considered a model to the study of South American faunas after the arrival of hystricomorph rodents and anthropoid primates but before GABI.
英文关键词	Ecometrics Paleobiology Paleoclimate Mammals Neogene South America Frugivore problem
类型	Article
语种	英语
开放获取类型	Bronze
收录类别	SCI-E
WOS记录号	WOS:000670261600002
WOS关键词	SOUTHERN SOUTH-AMERICA ; SANTACRUCIAN SLOTHS ; SPECIES RICHNESS ; FOSSIL ; MAMMALIA ; PATTERNS ; RODENTIA ; HYSTRICOGNATHI ; EVOLUTION ; AMEGHINO
WOS类目	Geosciences, Multidisciplinary
WOS研究方向	Geology
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/368591
作者单位	[Kay, Richard F.] Duke Univ, Dept Evolutionary Anthropol, Durham, NC 27708 USA; [Kay, Richard F.] Duke Univ, Div Earth & Ocean Sci, Durham, NC 27708 USA; [Vizcaino, Sergio F.; Susana Bargo, M.] Fac Ciencias Nat & Museo, Div Paleontol Vertebrados, Unidades Invest, Anexo Museo, Av 60 & 122, RA-1900 La Plata, Argentina; [Vizcaino, Sergio F.] Consejo Nacl Invest Cient & Tecn CONICET, Buenos Aires, DF, Argentina; [Susana Bargo, M.] Comis Invest Cient Prov Buenos Aires CICPBA, San Miguel De Tucuman, Argentina; [Spradley, Jackson P.] North Carolina State Univ, Coll Vet Med, Dept Mol Biomed Sci, Raleigh, NC USA; [Cuitino, Jose, I] Ctr Nacl Patag, Inst Patag Geol & Paleontol, U9120, Puerto Madryn, Argentina
推荐引用方式 GB/T 7714	Kay, Richard F.,Vizcaino, Sergio F.,Susana Bargo, M.,et al. Paleoenvironments and paleoecology of the Santa Cruz Formation (early-middle Miocene) along the Rio Santa Cruz, Patagonia (Argentina)[J],2021,109.
APA	Kay, Richard F.,Vizcaino, Sergio F.,Susana Bargo, M.,Spradley, Jackson P.,&Cuitino, Jose, I.(2021).Paleoenvironments and paleoecology of the Santa Cruz Formation (early-middle Miocene) along the Rio Santa Cruz, Patagonia (Argentina).JOURNAL OF SOUTH AMERICAN EARTH SCIENCES,109.
MLA	Kay, Richard F.,et al."Paleoenvironments and paleoecology of the Santa Cruz Formation (early-middle Miocene) along the Rio Santa Cruz, Patagonia (Argentina)".JOURNAL OF SOUTH AMERICAN EARTH SCIENCES 109(2021).