Publications by authors named "Jorge G Martínez"

5 Publications

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Ancient parasitic DNA reveals presence in Final Pleistocene of South America.

Parasitology 2019 09 3;146(10):1284-1288. Epub 2019 Jul 3.

Laboratorio de Parasitología de Sitios Arqueológicos, CONICET-UNMdP, Dean Funes 3250 (7600), Mar del Plata, Buenos Aires, Argentina.

Parasitological analysis of coprolites has allowed exploring ecological relationships in ancient times. Ancient DNA analysis contributes to the identification of coprolites and their parasites. Pleistocene mammalian carnivore coprolites were recovered from paleontological and archaeological site Peñas de las Trampas 1.1 in the southern Puna of Argentina. With the aim of exploring ancient ecological relationships, parasitological analysis was performed to one of them, dated to 16 573-17 002 calibrated years BP, with 95.4% probability. Parasite eggs attributed to Toxascaris sp. by morphological characters were isolated. DNA of coprolite and eggs was extracted to molecular identification. Ancient mitochondrial DNA analysis confirmed the zoological origin of the coprolite as Puma concolor and that of parasite eggs as Toxascaris leonina. This is the oldest molecular parasite record worldwide, and it supports the presence of this parasite since the Pleistocene in America. These findings have implications for the biogeographic history of parasites and for the natural history of the region.
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http://dx.doi.org/10.1017/S0031182019000787DOI Listing
September 2019

Ancient Mitogenomes Reveal the Evolutionary History and Biogeography of Sloths.

Curr Biol 2019 06 6;29(12):2031-2042.e6. Epub 2019 Jun 6.

McMaster Ancient DNA Centre, Departments of Anthropology and Biochemistry, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4L8, Canada. Electronic address:

Living sloths represent two distinct lineages of small-sized mammals that independently evolved arboreality from terrestrial ancestors. The six extant species are the survivors of an evolutionary radiation marked by the extinction of large terrestrial forms at the end of the Quaternary. Until now, sloth evolutionary history has mainly been reconstructed from phylogenetic analyses of morphological characters. Here, we used ancient DNA methods to successfully sequence 10 extinct sloth mitogenomes encompassing all major lineages. This includes the iconic continental ground sloths Megatherium, Megalonyx, Mylodon, and Nothrotheriops and the smaller endemic Caribbean sloths Parocnus and Acratocnus. Phylogenetic analyses identify eight distinct lineages grouped in three well-supported clades, whose interrelationships are markedly incongruent with the currently accepted morphological topology. We show that recently extinct Caribbean sloths have a single origin but comprise two highly divergent lineages that are not directly related to living two-fingered sloths, which instead group with Mylodon. Moreover, living three-fingered sloths do not represent the sister group to all other sloths but are nested within a clade of extinct ground sloths including Megatherium, Megalonyx, and Nothrotheriops. Molecular dating also reveals that the eight newly recognized sloth families all originated between 36 and 28 million years ago (mya). The early divergence of recently extinct Caribbean sloths around 35 mya is consistent with the debated GAARlandia hypothesis postulating the existence at that time of a biogeographic connection between northern South America and the Greater Antilles. This new molecular phylogeny has major implications for reinterpreting sloth morphological evolution, biogeography, and diversification history.
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http://dx.doi.org/10.1016/j.cub.2019.05.043DOI Listing
June 2019

Collagen Sequence Analysis of the Extinct Giant Ground Sloths Lestodon and Megatherium.

PLoS One 2015 5;10(11):e0139611. Epub 2015 Nov 5.

Instituto Superior de Estudios Sociales-CONICET, Instituto de Arqueología y Museo-UNT, Tucumán Province, Argentina.

For over 200 years, fossils of bizarre extinct creatures have been described from the Americas that have ranged from giant ground sloths to the 'native' South American ungulates, groups of mammals that evolved in relative isolation on South America. Ground sloths belong to the South American xenarthrans, a group with modern although morphologically and ecologically very different representatives (anteaters, armadillos and sloths), which has been proposed to be one of the four main eutherian clades. Recently, proteomics analyses of bone collagen have recently been used to yield a molecular phylogeny for a range of mammals including the unusual 'Malagasy aardvark' shown to be most closely related to the afrotherian tenrecs, and the south American ungulates supporting their morphological association with condylarths. However, proteomics results generate partial sequence information that could impact upon the phylogenetic placement that has not been appropriately tested. For comparison, this paper examines the phylogenetic potential of proteomics-based sequencing through the analysis of collagen extracted from two extinct giant ground sloths, Lestodon and Megatherium. The ground sloths were placed as sister taxa to extant sloths, but with a closer relationship between Lestodon and the extant sloths than the basal Megatherium. These results highlight that proteomics methods could yield plausible phylogenies that share similarities with other methods, but have the potential to be more useful in fossils beyond the limits of ancient DNA survival.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0139611PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4634953PMC
June 2016

Ticks (Acari: Argasidae, Ixodidae) from Middle and pre-Hispanic Late Holocene associated with human activities in northwestern Argentina.

Ticks Tick Borne Dis 2013 Feb 9;4(1-2):167-9. Epub 2012 Nov 9.

Instituto Nacional de Tecnología Agropecuaria, Estación Experimental Agropecuaria Rafaela and Consejo Nacional de Investigaciones Científicas y Técnicas, Rafaela, Santa Fe, Argentina.

One male of Amblyomma parvitarsum and one male and a female of Ornithodoros sp. were recovered from archaeological layers of the Middle Holocene in a rock shelter in the province of Catamarca, used by hunter-gatherer groups. Another two ticks identified as a female and a nymph of Argas cf. neghmei were recovered from a layer of the Late Holocene in other rock shelter in the province of Tucumán used by humans of agro-pastoral complex societies previous to the Hispanic invasion. The presence of Amblyomma parvitarsum is probably related to hunting activity, while Ornithodoros sp. was probably an opportunistic parasite established in the shelter. Argas cf. neghmei was probably a parasite of birds as is A. neghmei, a tick that has been found in the nests of birds, chicken houses, but also in human dwellings. The presence of A. cf. neghmei may originate from birds naturally breeding in the shelter or from the nests of birds introduced into the shelter by humans.
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http://dx.doi.org/10.1016/j.ttbdis.2012.10.037DOI Listing
February 2013