Flavia Morello

Revising the recent evolutionary history of equids using ancient DNA

The rich fossil record of the family Equidae (Mammalia: Perissodactyla) over the past 55 MY has made it an icon for the patterns and processes of macroevolution. Despite this, many aspects of equid phylogenetic relationships and taxonomy remain unresolved. Recent genetic analyses of extinct equids have revealed unexpected evolutionary patterns and a need for major revisions at the generic, subgeneric, and species levels. To investigate this issue we examine 35 ancient equid specimens from four geographic regions (South America, Europe, Southwest Asia, and South Africa), of which 22 delivered 87–688 bp of reproducible aDNA mitochondrial sequence. Phylogenetic analyses support a major revision of the recent evolutionary history of equids and reveal two new species, a South American hippidion and a descendant of a basal lineage potentially related to Middle Pleistocene equids. Sequences from specimens assigned to the giant extinct Cape zebra, Equus capensis, formed a separate clade within the modern plain zebra species, a phenotypicically plastic group that also included the extinct quagga. In addition, we revise the currently recognized extinction times for two hemione-related equid groups. However, it is apparent that the current dataset cannot solve all of the taxonomic and phylogenetic questions relevant to the evolution of Equus. In light of these findings, we propose a rapid DNA barcoding approach to evaluate the taxonomic status of the many Late Pleistocene fossil Equidae species that have been described from purely morphological analyses.

Hunter-gatherers, biogeographic barriers and the development of human settlement in Tierra del Fuego

Tierra del Fuego represents the southernmost limit of human settlement in the Americas. While people may have started to arrive there around 10 500 BP, when it was still connected to the mainland, the main wave of occupation occurred 5000 years later, by which time it had become an island. The co-existence in the area of maritime hunter-gatherers (in canoes) with previous terrestrial occupants pre-echoes the culturally distinctive groups encountered by the first European visitors in the sixteenth century. The study also provides a striking example of interaction across challenging natural barriers.

The southernmost bear: Pararctotherium (Carnivora, Ursidae, Tremarctinae) in the latest Pleistocene of southern Patagonia, Chile

FRANCISCO J. PREVOSTI1, LEOPOLDO H. SOIBELZON2, ALFREDO PRIETO3, MANUEL SAN ROMAN4, and FLAVIA MORELLO3, 1Facultad de Ciencias Naturales y Museo (U.N.L.P.), cc 223, 1900 La Plata, Buenos Aires, Argentina, protocyon@hotmail.com; 2CONICET, Departamento Cientı́fico Paleontologı́a de Vertebrados, Museo de La Plata, Paseo del Bosque, 1900 La Plata, Buenos Aires, Argentina; 3Centro de Estudios del Hombre Austral, Instituto de la Patagonia, UMAG Casilla 113-D, Punta Arenas, Chile; 4Centro de Estudios del Cuaternario de Fuego-Patagonia y Antártica Chilena, Casilla 113-D, Punta Arenas, Chile

Antiquity and geographic distribution of cranial modification among the prehistoric groups of Fuego-Patagonia, Chile.

OBJECTIVES Nineteenth and twentieth century documents testify that four ethnic groups, generally classified as terrestrial hunters or canoe nomads, inhabited Fuego-Patagonia. Archaeologically, however, their presence and temporal depth remains unknown. This study analyzes the antiquity and geographic distribution of cranial modification, a highly visible symbol of social identity, in Fuego-Patagonia, Chile, to assess whether it expressed ethnic affiliation. MATERIALS AND METHODS A total of 60 adult skulls from Southern Patagonia (n = 32; 53.3%) and Tierra del Fuego (n = 28; 46.7%) were examined for age-at-death, sex and cranial modification with standard methods. Individuals were further categorized as terrestrial (n = 26; 43.3%), marine (n = 21; 35%) or indetermined hunter-gatherers (n = 13; 21.7%) based on the archaeological sites characteristics, geographic location, and isotopic information. RESULTS Thirty percent (n = 18) of the skulls in this study were modified, and most of the modified skulls (n = 15) presented a tabular-erect shape. No statistically significant differences were identified between Fuegians and Patagonians, males or females, or between the different types of adaptation and geographic locations. DISCUSSION Thus, this Late Holocene, widely distributed practice, was not a reflection of ethnicity, but a material expression of information circulation and the complex social relations that these small-size groups had with one another. These results suggest that the emergence of modern ethnic identities in the region is a historic process that resulted from the interaction of local groups with European and Criollos.

Una encrucijada de caminos: el poblamiento de la Isla Dawson (Estrecho de Magallanes)

Se presenta un estudio sobre el rol del poblamiento humano prehistorico de isla Dawson, zona central del estrecho de Magallanes, a traves de la discusion de los resultados recopilados en una extensa prospeccion que abarco la costa este de la isla y su comparacion con otros nucleos canoeros. El descubrimiento de 29 sitios arqueologicos permitio registrar evidencias ineditas de ocupaciones humanas datadas entre ca. 4200 y 1200 anos A P. Podrian representar un vinculo entre los dos nucleos de poblamiento canoero de la zona austral, el mar de Otway/peninsula Brunswick y el canal Beagle.

EL SITIO ARQUEOLÓGICO MYREN 2, TIERRA DEL FUEGO, CHILE

Se da cuenta del contexto de un sitio arqueologico de especiales caracteristicas, por hallarse inmerso en un antiguo turbal y por su datacion de ca. 4.000 anos AP. Los analisis liticos y arqueofaunisticos del sitio Myren 2 apoyan la idea de que se trata de un sitio de dificil adscripcion funcional, pero muy interesante por la informacion que entrega y su caracter ejemplar para la Tierra del Fuego

NUEVAS EVIDENCIAS DE CAZADORES RECOLECTORES TERRESTRES DEL HOLOCENO MEDIO Y TARDÍO EN TIERRA DEL FUEGO: EL SITIO CABO MONMOUTH 20

The Cabo Monmouth 20 site represents new evidence of Middle and Late Holocene occupations (ca. 5.000 years BP) for the north of Isla Grande, Tierra del Fuego. In this paper we evaluate archaeo- logical evidence from a test pit excavation, synthesize stratigraphic and contextual data, and present a new radiocarbon date (5,520 + 50 years BP) on shell material of anthropic origin. The latter confirms the antiquity of the site, highlighting the presence of archaeological deposits in a co-eval palaeosol.

Arqueología de la Punta Santa Ana: recontrucción de secuencias de ocupación de cazadores-recolectores marinos del Estrecho de Magallanes, Patagonia Austral, Chile

We present results of research focused on the identification of sites and the analysis of their archaeo - logical evidence in order to reconstruct occupation sequences of marine hunter-gatherer groups at specific localities of Southernmost Patagonia. In this paper we address the characterization of three archaeological sites at Punta Santa Ana area, Strait of Magellan. The studied assemblages are from camp-sites located at

Assessment of an east-west phenotypic variation in body height, body form and body mass among prehistoric hunter-gatherers of Patagonia and Tierra del Fuego, chile

espanolResumen: Historicamente grupos marinos y terrestres de Fuego-Patagonia fueron descritos como fenotipicamente distintos. Este estudio examina la presencia de esta variacion fenotipica, la cual de existir, podria ser resultado de factores extrinsecos, como son los procesos adaptativos de corto o largo plazo e intrinsecos como son los factores geneticos. La muestra se compone de 51 individuos adultos. Se incluyeron seis mediciones post-craneales: longitud maxima del humero (MHL); longitud maxima del radio (MRL); longitud bicondilar del femur (BFL); longitud maxima de la tibia (MTL); ancho bi-iliaco (BIB), y; diametro antero-posterior de la cabeza femoral (FHD). Tambien se calcularon el indice braquial, el crural, la masa corporal, el indice de masa y la estatura. En general, los individuos terrestres tenian huesos de la extremidad inferior mas largos y eran por ende mas altos y pesados. Los individuos marinos tenian los huesos mas cortos y eran mas bajos y livianos. Los individuos de economia mixta mostraron valores intermedios. Esto sugiere la presencia de una gradiente fenotipica de este a oeste, que es mas marcada en individuos masculinos, y que puede haber resultado de diferencias extrinsecas y/o intrinsecas. Sin embargo, dado el tamano pequeno de la muestra, estos resultados deben ser considerados con cautela. EnglishAbstract: Fuego-Patagonia’s marine and terrestrial groups were historically described as phenotypically distinct but, studies of these phenotypic differences have yet to be conducted. This study evaluates phenotypic variation in Fuego-Patagonia. Phenotypic disparities result from extrinsic and intrinsic factors and therefore can reveal differences in both long and short term adaptations as well as genetic differences. Fifty-one adults were assessed. A total of six post-cranial measurements were included: maximum length of the humerus (MHL); maximum length of the radius (MRL); Bicondylar length of the femur (BFL); Maximum length of the tibia (MTL); bi-iliac breadth (BIB), and; antero-posterior diameter of the femoral head (FHD). Brachial index, crural index, body mass, body mass index and stature were then calculated. In general, terrestrial individuals had longer lower limb bones and were the tallest and heaviest. Marine individuals had the shortest bones and were shorter and lighter. Mixed-economy individuals showed mostly intermediate values. The trends are more marked in males than in females. The results suggests the presence of an east-to-west phenotypic gradient in the region that may have resulted from intrinsic and/or extrinsic differences between the groups. But, the sample size of this study is small, and thus the results should be cautiously considered.