Research projects

Prof. Dr. Marcelo Sánchez

Palaeobiology of fossil vertebrates in South America

Leadership/contacts

Duration

March 2007 to December 2026

Funding sources

Others
National Geographic Society (turtle project); Previous funding supported by SNF, National Geographic Society, Universität Tübingen, Natural History Museum London, and the Percy Sladen Memorial Fund.

Collaborations

Summary

Vertebrate palaeontology of the northern Neotropics is almost non-existent and hence there are many unanswered questions about biogeography and evolution in that part of the world. Of particular significance is the exploration for new fossils to test: 1) a hypothesis on the origin of the Caribbean fauna, involving a land connection between Nortwestern South America and the Greater Antilles, and 2) the changing course of the Orinoco River, hypothesized to have had its delta during late Palaeogene and early Neogene times in what is today northwestern Venezuela.
The goals of this project are to: (1) explore poorly known areas of Venezuela and Colombia for fossil vertebrates (while collecting also for invertebrates for palaeoenvironmental reconstruction or for stratigraphic work); (2) describe fossil faunas, including species descriptions; and (3) conduct palaeobiological studies (e.g., palaeohistology) aiming at reconstructing life history and ecological variables in the extinct species there studied; (4) expand this work to higher latitudes to make faunal comparisons and test differnet hypotheses about the evolution of diverse vertebrate groups.

Keywords

Gondwana, Venezuela, vertebrates, biogeography, palaeobiology

Publications

Benites-Palomino A, Aguirre-Fernandez G, Velez-Juarbe J, Carrillo-Briceño JD, Sanchez R, Sánchez-Villagra MR. Trophic interactions of sharks and crocodylians with a sea cow from the Miocene of Venezuela. Journal of Vertebrate Paleontology (in press)

Benites-Palomino A, Aguirre-Fernández G, Baby P, Ochoa D, Altamirano A, Flynn JJ, Sánchez-Villagra MR, Tejada JV, de Muizon C, Salas-Gismondi R (2024) The largest freshwater odontocete: a South Asian river dolphin relative from the proto-Amazonia. Science Advances 10 (12):eadk6320 [doi: 10.1126/sciadv.adk6320].

Carrillo-Briceño JD, Ruiz-Ramoni D, Sánchez R, Jaimes A, Chávez-Aponte E, Prevosti FJ, Segura V, Carlini AA, Garbé L, Tombret O, Zazzo A, Sánchez-Villagra MR (2024) Cauca: megafaunal and felid fossils (Mammalia) from a Pleistocene site in northwest Venezuela. Fossil Record 27 (1):187-207.

Ferreira JD, Rinderknecht A, de Moura Bubadué J, Flores Gasparetto L, Dozo MT, Sánchez-Villagra MR, Kerber L (2024) Unveiling the neuroanatomy of Josephoartigasia monesi and the evolution of encephalization in caviomorph rodents. Brain Structure and Function 229 (4):971-985

Sánchez-Villagra MR, Bond M, Reguero M, Bartoletti T J (2023) From fossil trader to palaeontologist: on Swiss-born naturalist Santiago Roth and his scientific contributions. Swiss Journal of Palaeontology 142:19 [doi: 10.1186/s13358-023-00282-6].

Viglino M, Valenzuela-Toro AM, Benites-Palomino A, Hernández-Cisneros AE, Gutstein CS, Aguirre-Fernández G, Velez-Juarbe J, Cozzuol MA, Buono MR, Loch C (2023) Aquatic mammal fossils in Latin America–a review of records, advances and challenges in research in the last 30 years. The Latin American Journal of Aquatic Mammals 18 (1):50-66.

Voglino D, Carrillo-Briceño JD, Furrer H, Balcarcel A, Rangel-de Lazaro G, Aguirre Fernández G, Forasiepi AM (2023) Pampean megamammals in Europe: the fossil collections from Santiago Roth. Swiss Journal of Palaeontology 142 (1):25

Reyes-Céspedes AE, Carlini AA, Carrillo-Briceño JD (2023) New record of Pachyarmatherium (Cingulata: Pachyarmatheriidae) from the Late Pleistocene in Venezuela. Anartia 35:7–13 [doi: 10.5281/zenodo.7951590].

Ronez C, Carrillo-Briceño JD, Hadler P, Sánchez-Villagra MR, Pardiñas UFJ (2023) Pliocene sigmodontine rodents (Mammalia: Cricetidae) in northernmost South America: test of biogeographic hypotheses and revised evolutionary scenarios. Royal Society Open Science 10 (8):221417 [doi: 10.1098/rsos.221417].

Ruiz-Ramoni D, Carrillo-Briceño JD, Voglino D, Prevosti FJ (2023) Carnivoran fossils from the Pampean region (Argentina): Santiago Roth collections in Switzerland. Swiss Journal of Palaeontology 142 (1):11

Le Verger K (2023) Xenarthrans of the collection of Santiago Roth from the Pampean Region of Argentina (Pleistocene), in Zurich, Switzerland. Swiss Journal of Palaeontology 142 (1):3 [doi: 10.1186/s13358-023-00265-7].

Bianucci G, Lambert O, Urbina M, Merella M, Collareta A, Bennion R, Salas-Gismondi R, Benites-Palomino A, Post K, de Muizon C, Bosio G, Di Celma C, Malinverno E, Pierantoni PP, Villa IM, Amson E (2023) A heavyweight early whale pushes the boundaries of vertebrate morphology. Nature [doi: 10.1038/s41586-023-06381-1].

Cadena E-A, Link A, Vanegas A, Avellaneda-Otero CA, Perdomo C, Urueña-Carrillo DA, Sánchez R, Vanegas RD, Scheyer TM, Carrillo-Briceño JD (2023) New insights into the fossil record of the turtle genus Chelus Duméril, 1806 including new specimens with information on cervicals and limb bones. Comptes Rendus Palevol 2023 (34):689-709 [doi:10.5852/cr-palevol2023v22a34].

Carrillo JD, Suarez C, Benites-Palomino AM, Vanegas A, Link A, Rincón AF, Luque J, Cooke SB, Tallman M, Billet G (2023). New remains of Neotropical bunodont litopterns and the systematics of Megadolodinae (Mammalia: Litopterna). Geodiversitas, 45(15):409-447.

Carrillo-Briceño JD, Mora-Rojas L, Hendricks K, Vanegas A, Aguilera O (2023) New clues on the palaeodiversity of the middle Miocene freshwater ichthyofauna from the Tatacoa Desert, Colombia, in Carrillo JD (ed), Neotropical palaeontology: the Miocene La Venta biome. Geodiversitas 45 (10): 327-351.

Carrillo-Briceño JD, Vezzosi RI, Ming KM, Christen ZM, Mothé D, Ruiz-Ramoni D, Sánchez-Villagra MR (2023) Nearctic Pleistocene ungulates from the Pampean region (Argentina) in the historical collections of Santiago Roth in Switzerland: an overview. Swiss Journal of Palaeontology 142 (1):12 [doi: 10.1186/s13358-023-00273-7].

Christen ZM, Sánchez-Villagra MR, Le Verger K (2023) Cranial and endocranial comparative anatomy of the Pleistocene glyptodonts from the Santiago Roth Collection. Swiss Journal of Palaeontology 142 (1):14 [doi: 10.1186/s13358-023-00280-8].

Forasiepi AM, Aguirre-Fernández G (2023) Santiago Roth and his scientific legacy: a reappraisal of the Swiss collections. Swiss Journal of Palaeontology 142 (1):29 [doi: 10.1186/s13358-023-00287-1].

Irmis RB, Mundil R, Mancuso AC, Carrillo-Briceño JD, Ottone EG, Marsicano CA (2022) South American Triassic geochronology: constraints and uncertainties for the tempo of Gondwanan non-marine vertebrate evolution. Journal of South American Earth Sciences:103770
Carlini AA, Carrillo-Briceño JD, Jaimes A, Aguilera O, Zurita AE, Iriarte J, Sánchez-Villagra MR (2022) Damaged glyptodontid skulls from Late Pleistocene sites of northwestern Venezuela: evidence of hunting by humans? Swiss Journal of Palaeontology 141 (1):11
Carrillo-Briceño JD, Cadena E-A (2022) A new hybodontiform shark (Strophodus Agassiz 1838) from the Lower Cretaceous (Valanginian-Hauterivian) of Colombia. PeerJ 10:e13496
Benites-Palomino A, Velez-Juarbe J, Altamirano-Sierra A, Collareta A, Carrillo-Briceño JD, Urbina M (2022) Sperm whales (Physeteroidea) from the Pisco Formation, Peru, and their trophic role as fat sources for late Miocene sharks. Proceedings of the Royal Society B: Biological Sciences 289
Benites-Palomino A, Valenzuela-Toro AM, Figueroa-Bravo C, Varas-Malca RM, Nielsen SN, Gutstein CS, Carrillo-Biceño JD (2022) A new marine mammal assemblage from central Chile reveals the Pliocene survival of true seals in South America. Historical Biology:1-13
Benites-Palomino A, Reyes-Cespedes AE, Aguirre-Fernández G, Sanchez R, Carrillo-Briceño JD, Sánchez-Villagra MR (2021) A stem delphinidan from the Caribbean region of Venezuela. Swiss Journal of Palaeontology 140(1):6
Carrillo-Briceño JD, Sánchez R, Scheyer TM, Carrillo JD, Delfino M, Georgalis GL, Kerber L, Ruiz-Ramoni D, Birindelli JLO, Cadena EA, Rincón AF, Chavez-Hoffmeister M, Carlini AA, Carvalho MR, Trejos-Tamayo R, Vallejo F, Jaramillo C, Jones DS, Sánchez-Villagra MR (2021) A Pliocene–Pleistocene continental biota from Venezuela. Swiss Journal of Palaeontology 140(1):9
Herrera-Castillo CM, Carrillo-Briceño JD, Sánchez-Villagra MR (2021) Non-invasive imaging reveals new cranial element of the basal ornithischian dinosaur Laquintasaura venezuelae, Early Jurassic of Venezuela. Anartia 32:53-60.
Cadena E-A, Scheyer TM, Carrillo-Briceño JD, Sánchez R, Aguilera-Socorro OA, Vanegas A, Pardo M, Hansen DM, Sánchez-Villagra MR (2020) The anatomy, paleobiology, and evolutionary relationships of the largest extinct side-necked turtle. Science Advances 6 (7):eaay4593
Villafaña JA, Marramà G, Hernandez S, Carrillo-Briceño JD, Hovestadt D, Kindlimann R, Kriwet J (2019) The Neogene fossil record of Aetomylaeus (Elasmobranchii, Myliobatidae) from the south-eastern Pacific. Journal of Vertebrate Paleontology:e1577251.
Zurita-Altamirano D, Buffetaut E, Forasiepi AM, Kramarz A, Carrillo JD, Aguirre-Fernández G, Carlini AA, Scheyer TM, Sánchez-Villagra MR (2019) The Allemann Collection from the Santa Cruz Formation (Late Early Miocene), Argentina, In Zurich, Switzerland. Swiss Journal of Palaeontology 138:259-275.
Scheyer TM, Hutchinson JR, Strauss O, Delfino M, Carrillo-Briceño JD, Sánchez R, Sánchez-Villagra MR (2019) Giant extinct caiman breaks constraint on the axial skeleton of extant crocodylians. eLife 8:e49972
Salas-Gismondi R, Moreno-Bernal JW, Scheyer TM, Sánchez-Villagra MR, Jaramillo C (2019) New Miocene Caribbean gavialoids and patterns of longirostry in crocodylians. Journal of Systematic Palaeontology 17 (12):1049-1075
Cadena EA, Carrillo-Briceño JD (2019) First fossil of Rhinoclemmys Fitzinger, 1826 (Cryptodira, Geoemydidae) east of the Andes. South American Journal of Herpetology 14 (1):19-23.
Carrillo-Briceño JD, Luz Z, Hendy A, Kocsis L, Aguilera O, Vennemann T (2019) Neogene Caribbean elasmobranchs: diversity, paleoecology and paleoenvironmental significance of the Cocinetas Basin assemblage (Guajira Peninsula, Colombia). Biogeosciences 16 (1):33-56.
Carrillo-Briceño JD, Parra JD, Luque J (2019) A new lamniform shark Protolamnaricaurtei sp. nov. from the Lower Cretaceous of Colombia. Cretaceous Research 95:336-340.
Carrillo-Briceño JD, Carrillo JD, Aguilera OA, Sánchez-Villagra MR (2018) Shark and ray diversity in the Tropical America (Neotropics) – an examination of environmental and historical factors affecting diversity, PeerJ 6:e5313.
Carrillo JD, Amson E, Jaramillo C, Sánchez R, Quiroz L, Cuartas C, Rincón AF, Sánchez-Villagra MR (2018) The Neogene record of Northern South American native ungulates. Smithsonian Contributions to Palaeobiology 101:67 pp.
Carrillo JD, Amson E, Jaramillo C, Sánchez R, Quiroz L, Cuartas C, Rincón A, Sánchez-Villagra MR (2018) 3D models related to the publication: The Neogene record of northern South American native ungulates. MorphoMuseuM 4:e61.
Delfino M, Sánchez-Villagra MR (2018) A Late Miocene pipine frog from the Urumaco Formation, Venezuela. Ameghiniana 55 (2):210-214. [doi: 10.5710/AMGH.04.10.2017.3136].
Kerber L, Sánchez-Villagra MR (2018) Morphology of the middle ear ossicles in the rodent Perimys (Neoepiblemidae) and a comprehensive anatomical and morphometric study of the phylogenetic transformations of these structures in caviomorphs. Journal of Mammalian Evolution:1-16.
Albino AM, Rothschild B, Carrillo-Briceño JD, Neenan JM (2018) Spondyloarthropathy in vertebrae of the aquatic Cretaceous snake Lunaophis aquaticus, and its first recognition in modern snakes. The Science of Nature 105:51 [doi: 10.1007/s00114-018-1576-7].
Carlini AA, Brandoni D, Sánchez R, Sánchez-Villagra MR (2018) A new Megatheriinae skull (Xenarthra, Tardigrada) from the Pliocene of Northern Venezuela - implications for a giant sloth dispersal to Central and North America. Palaeontologia Electronica 21.2.16A:1-12
Dentzien-Dias P, Carrillo-Briceño JD, Francischini H, Sánchez R (2018) Paleoecological and taphonomical aspects of the Late Miocene vertebrate coprolites (Urumaco Formation) of Venezuela. Palaeogeography, Palaeoclimatology, Palaeoecology 490:590-603 [doi: 10.1016/j.palaeo.2017.11.048].
Guinot G, Carrillo-Briceño JD (2018) Lamniform sharks from the Cenomanian (Upper Cretaceous) of Venezuela. Cretaceous Research 82:1-20.
Aguirre-Fernández G, Carrillo-Briceño JD, Sánchez R, Amson E, Sánchez-Villagra MR (2017) Fossil Cetaceans (Mammalia, Cetacea) from the Neogene of Colombia and Venezuela. Journal of Mammalian Evolution 24(1): 71–90.
Carrillo JD, Asher RJ (2017) An exceptionally well-preserved skeleton of Thomashuxleya externa (Mammalia, Notoungulata), from the Eocene of Patagonia, Argentina. Palaeontologia Electronica 20 (2):1-33.
Aguirre-Fernández G, Mennecart B, Sánchez-Villagra MR, Sánchez R, Costeur L (2017) A dolphin fossil ear bone from the northern Neotropics–insights into habitat transitions in iniid evolution. Journal of Vertebrate Paleontology:e1315817.
Carrillo-Briceño JD, Argyriou T, Zapata V, Kindlimann R, Jaramillo C (2016) A new early Miocene (Aquitanian) Elasmobranchii assemblage from the la Guajira Peninsula, Colombia. Ameghiniana 53:77–99.
Aguilera O, Luz Z, Carrillo-Briceño JD, Kocsis L, Vennemann TW, de Toledo PM, Nogueira A, Amorim KB, Moraes-Santos H, Polck MR, Ruivo MdL, Linhares AP, Monteiro-Neto C (2017) Neogene sharks and rays from the Brazilian ‘Blue Amazon’. Plos One 12 (8):e0182740.
De Los Arcos S, Partarrieu D, Carrillo-Briceño JD, Amson E (2017) The southernmost occurrence of the aquatic sloth Thalassocnus (Mammalia, Tardigrada) in two new Pliocene localities in Chile. Ameghiniana 54 (4):351-369.
Jaramillo C, Romero I, D’Apolito C, Bayona G, Duarte E, Louwye S, Escobar J, Luque J, Carrillo-Briceño JD, Zapata V, Mora A, Schouten S, Zavada M, Harrington G, Ortiz J, Wesselingh FP (2017) Miocene flooding events of western Amazonia. Science Advances 3 (5): e1601693.
Tanaka Y, Abella J, Aguirre-Fernández G, Gregori M, Fordyce RE (2017) A new tropical Oligocene dolphin from Montañita/Olón, Santa Elena, Ecuador. Plos One 12 (12):e0188380.
Aguilera O, Andrade Silva GO, Lopes RT, Machado AS, dos Santos TM, Marques G, Bertucci T, Aguiar T, Carrillo-Briceño JD, Rodriguez F, Jaramillo C (2017) Neogene Proto-Caribbean porcupinefishes (Diodontidae). Plos One 12 (7):e0181670.
Pérez LM, Pérez Panera JP, Aguilera OA, Ronchi DI, Sánchez R, Manceñido MO, Sánchez-Villagra MR. 2016 Palaeontology, sedimentology, and biostratigraphy of a fossiliferous outcrop of the Early Miocene Querales Formation, Falcón Basin, Venezuela. Swiss Journal of Palaeontology 135:187–203.
Carrillo-Briceño JD, Sánchez-Villagra MR (2015) Tortugas del pasado: una mirada al registro fósil en Venezuela. Pp. 165-181. In: Trebau P, Pritchard PCH Tortugas de Venezuela. Oscar Todtmann Editores.
Carrillo-Briceño JD, Cadena EA, Dececchi AT, Larson HCE, Du TY (2016) First record of a hybodont shark (Chondrichthyes: Hybodontiformes) from the Lower Cretaceous of Colombia. Neotropical Biodiversity 2(1):81-86.
Hastings A, Reisser M, Scheyer TM (2016) Character evolution and the origin of Caimaninae (Crocodylia) in the New World tropics: new evidence from the Miocene of Panama and Venezuela. Journal of Paleontology 90(2):317-332.
Amson E, Carrillo JD, Jaramillo C (2016) Neogene sloth assemblages (Mammalia, Pilosa) of the Cocinetas Basin (La Guajira, Colombia) implications for the Great American Biotic Interchange. Palaeontology 59 (4):563–582
Carrillo JD, Jaramillo C, Forasiepi AM, Sánchez-Villagra MR. 2015. Mammal Neotropical diversity and the Great American Biotic Interchange: a palaeontological perspective from northern South America. Frontiers in Genetics 5 (451):1-11 [doi: 10.3389/fgene.2014.00451].
Carrillo JD, Sánchez-Villagra MR. 2015. Giant rodents from the northern Neotropics: diversity and dental variation of late Miocene neoepiblemid remains from Urumaco, Venezuela. Paläontologische Zeitschrift 89:1057-1071.
Vallejo-Pareja MC, Carrillo JD, Moreno-Bernal JW, Pardo-Jaramillo M, Rodriguez-Gonzalez DF, Muñoz-Duran J (2015) Hilarcotherium castanedaii, gen. et sp. nov., a new Miocene astrapothere (Mammalia, Astrapotheriidae) from the Upper Magdalena Valley, Colombia. Journal of Vertebrate Paleontology 35(2): e903960
Carrillo-Briceño JD, Maxwell E, Aguilera OA, Sánchez R, Sánchez-Villagra MR (2015) Sawfishes and other elasmobranch assemblages from the Mio-Pliocene of the South Caribbean (Urumaco sequence, Northwestern Venezuela). PLoS ONE 10(10): e0139230
Moreno F, Hendy AJW, Quiroz L, Hoyos N, Jones DS, Zapata V, Zapata S, Ballen GA, Cadena E, Cárdenas AL, Carrillo-Briceño JD, Carrillo JD, Delgado-Sierra D, Escobar J, Martínez JI, Martínez C, Montes C, Moreno J, Pérez N, Sánchez R, Suárez C, Vallejo-Pareja MC, Jaramillo C (2015) Revised stratigraphy of Neogene strata in the Cocinetas Basin, La Guajira, Colombia. Swiss Journal of Palaeontology: 1-39
Forasiepi AM, Soibelzon LH, Suarez Gomez C, Sánchez R, Quiroz LI, Jaramillo C, Sánchez-Villagra MR. 2014. Carnivorans at the Great American Biotic Interchange: new discoveries from the northern Neotropics. Naturwissenschaften 101: 965-974.
Castro MC, Carlini AA, Sánchez R, Sánchez-Villagra MR 2014. A new Dasypodini (Xenarhtra: Cingulata) from San Gregorio Formation, Pliocene of Venezuela: Affinities and Biogeographic Interpretations. Naturwissenschaften [doi: 10.1007/s00114-013-1131-5].
Scheyer TM, Aguilera OA, Delfino M, Fortier DC, Carlini AA, Sánchez R, Carrillo-Briceño J, Quiroz L,
Sánchez-Villagra MR. 2013. Crocodylian diversity peak and extinction in the late Cenozoic of the northern Neotropics. Nature Communications. DOI: 10.1038/ncomms2940.
Geiger M, Wilson LAB, Costeur L, Sánchez R, Sánchez-Villagra MR. 2013. Diversity and growth in giant caviomorphs from the northern neotropics – a study of femoral variation in Phoberomys (Rodentia). Journal Vertebrate Paleontology 33: 1449-1456.
Aguilera O, Lundberg J, Birindelli J, Sabaj Pérez M, Jaramillo C, Sánchez-Villagra MR. 2013. Palaeontological evidence for the last temporal occurrence of the ancient western Amazonian river inflow into the Caribbean. Plos One 8(9):e76202. doi:10.1371/journal.pone.0076202.
Sánchez-Villagra MR (ed). 2012. Venezuela Paleontológica. Printworkart Press. 382 pp.
Aguilera OA, Feijó Ramos MI, Tavares Paes E, Regina Ferreira Costa SA, Sánchez-Villagra MR. 2011. The Neogene Tropical America Fish Assemblage and the Paleobiogeography of the Caribbean region. Swiss Journal of Palaeontology 130: 217-240.
Sánchez-Villagra MR, Aguilera OA, Carlini AA (eds). 2010. Urumaco and Venezuelan Palaeontology – The fossil record of the Northern Neotropics. Indiana University Press. 286 pp.
Mihaljevic M, Klug C, Aguilera O, Wyss P, Lüthi T, Sánchez-Villagra MR. 2010. Venezuelan echinoids: their fossil record and new material from the Neogene. Palaeontologia Electronica 13(3):20A:36p.
Vucetich MG, Carlini AA, Aguilera O, Sánchez-Villagra MR. 2010. The Tropics as reservoir of otherwise extinct mammals: the case of rodents from a new Pliocene faunal assemblage from northern Venezuela. Journal of Mammalian Evolution. 17:265-273.
Johnson KG, Sánchez-Villagra MR, Aguilera O. 2009. The Oligocene/Miocene transition on coral reefs in the Falcón Basin (NW Venezuela). Palaios. 24: 59-69.
Sánchez-Villagra MR, Aguilera O (eds). 2008. Vertebrate Palaeontology in Venezuela. Palaeontologische Zeitschrift. 82:103-245.
Sánchez-Villagra MR (ed). 2006. New Vertebrate Finds from the Neogene of Venezuela. Journal of Systematic Palaeontology. 4(3), 211-306.
Sánchez-Villagra MR, Clack JA (eds). 2004. Fossils of the Castillo Formation, Venezuela: Contributions on Neotropical Palaeontology. Special Papers in Palaeontology, 71. 112 pp.
Johnson KG, Sánchez-Villagra MR, Aguilera O. 2009. The Oligocene/Miocene transition on coral reefs in the Falcón Basin (NW Venezuela). Palaios. In press.
Barrett PM, Butler RJ, Novas FE, Moore-Fay S, Moody JM, Clark JM, Sánchez-Villagra MR. 2008. Dinosaur remains from the La Quinta Formation (Lower or Middle Jurassic) of the Venezuelan Andes. In: Vertebrate Palaeontology in Venezuela. Eds: Sánchez-Villagra MR., Aguilera O. Palaeontologische Zeitschrift. 82: 163-177.
Sánchez-Villagra MR, Brinkmann W, Lozsán R. 2008. The Palaeozoic and Mesozoic vertebrate record of Venezuela: An overview and summary of previous discoveries. In: Vertebrate Palaeontology in Venezuela. Eds: Sánchez-Villagra MR., Aguilera O. Palaeontologische Zeitschrift. 82: 113-124.
Scheyer T, Sánchez-Villagra MR. 2007. Carapace bone histology in the giant Stupendemys geographicus (Pleurodira: Podocnemidae): phylogenetic and functional aspects. Acta Palaeontologica Polonica 52:137-154.
Head JJ, Sánchez-Villagra MR, Aguilera O. 2006. Past colonization of South America by trionychid turtles: Fossil evidence from the Neogene of Margarita Island, Venezuela. Journal of Herpetology 40: 378-381.
Winkler JD, Sánchez-Villagra MR. 2006. A nesting site and egg morphology of a Miocene turtle from Urumaco, Venezuela: direct evidence of marine adaptations in a pelomedusoides . Palaeontology. 49: 641-646.
Sánchez-Villagra MR, Aguilera OA, Horovitz I. 2003. The anatomy of the world's largest extinct rodent. Science , 301: 1708-1710.