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2. Cranial form differences in goats by breed and domestic status

Author

Balcarcel, A M; https://orcid.org/0000-0002-3826-834X, Geiger, M, Sánchez-Villagra, M R; https://orcid.org/0000-0001-7587-3648, Balcarcel, A M; https://orcid.org/0000-0002-3826-834X, Geiger, M, and Sánchez-Villagra, M R; https://orcid.org/0000-0001-7587-3648

Abstract

Domestic goats (Capra hircus) are globally represented by over 300 breeds, making them a useful model for investigating patterns of morphological change related to domestication. However, they have been little studied, likely due to their poor representation in museum collections and the difficulty in obtaining truly wild goat (Capra aegagrus, the bezoar) samples. Similar studies on other species reveal that domestication correlates with craniofacial alterations in domestics, which are non-uniform and often species-specific. Here, we use three-dimensional geometric morphometric methods (3DGMM) to describe and quantify cranial shape variation in wild (n = 21) versus domestic (n = 54) goats. We find that mean cranial shapes differ significantly between wild and domestic goats as well as between certain breeds. The detected differences are lower in magnitude than those reported for other domestic groups, possibly explained by the fewer directions of artificial selection in goat breeding, and their low global genetic diversity compared to other livestock. We also find tooth-row length reduction in the domestics, suggestive of rostral shortening—a prediction of the “domestication syndrome” (DS). The goat model thus expands the array—and combinations of—morphological changes observed under domestication, notably detecting alterations to the calvarium form which could be related to the ~ 15% brain size reduction previously reported for domestic compared to wild goats. The global success of domestic goats is due more to their ability to survive in a variety of harsh environments than to systematized human management. Nonetheless, their domestication has resulted in a clear disruption from the wild cranial form, suggesting that even low-intensity selection can lead to significant morphological changes under domestication.

Published
2024

6. The mammalian brain under domestication: Discovering patterns after a century of old and new analyses.

Author

Balcarcel, A. M., Geiger, M., Clauss, M., and Sánchez‐Villagra, M. R.

Subjects
SIZE of brain, MODERN literature, ARTIODACTYLA, CARNIVORA
Abstract

Comparisons of wild and domestic populations have established brain reduction as one of the most consistent patterns correlated with domestication. Over a century of scholarly work has been devoted to this subject, and yet, new data continue to foster its debate. Current arguments, both for and against the validity of brain reduction occurring in domestic taxa, have repeatedly cited a small set of reviews on this subject. The original works, their sampling, methodological details, and nuances of results that would be key to establishing validity, particularly in light of new data, have not been investigated. To facilitate and encourage a more informed discussion, we present a comprehensive review of original brain reduction literature for four mammalian clades: Artiodactyla, Perissodactyla, Carnivora, and Glires. Among these are studies that generated the most cited brain reduction values in modern domestication literature. In doing so, we provide a fairer stage for the critique of traits associated with domestication. We conclude that while brain reduction magnitudes may contain error, empirical data collectively support the reduction in brain size and cranial capacity for domestic forms. Highlights: Studies finding brain size reduction in domestic mammals vary by method, result, and sampling.There is a general tendency toward brain size reduction following domestication, but no universal pattern of amount or kind.Breed variation is a subject for further research in this area. [ABSTRACT FROM AUTHOR]

Published
2022
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9. Exceptional Changes in Skeletal Anatomy under Domestication: The Case of Brachycephaly

Author

Geiger, M, Schoenebeck, J J, Schneider, R A, Schmidt, M J, Fischer, M S, Sánchez-Villagra, M R, and University of Zurich

Subjects
1105 Ecology, Evolution, Behavior and Systematics, 560 Fossils & prehistoric life, 1110 Plant Science, AcademicSubjects/SCI00960, Review, 10125 Paleontological Institute and Museum, 1103 Animal Science and Zoology
Abstract

Synopsis “Brachycephaly” is generally considered a phenotype in which the facial part of the head is pronouncedly shortened. While brachycephaly is characteristic for some domestic varieties and breeds (e.g., Bulldog, Persian cat, Niata cattle, Anglo-Nubian goat, Middle White pig), this phenotype can also be considered pathological. Despite the superficially similar appearance of “brachycephaly” in such varieties and breeds, closer examination reveals that “brachycephaly” includes a variety of different cranial modifications with likely different genetic and developmental underpinnings and related with specific breed histories. We review the various definitions and characteristics associated with brachycephaly in different domesticated species. We discern different types of brachycephaly (“bulldog-type,” “katantognathic,” and “allometric” brachycephaly) and discuss morphological conditions related to brachycephaly, including diseases (e.g., brachycephalic airway obstructive syndrome). Further, we examine the complex underlying genetic and developmental processes and the culturally and developmentally related reasons why brachycephalic varieties may or may not be prevalent in certain domesticated species. Knowledge on patterns and mechanisms associated with brachycephaly is relevant for domestication research, veterinary and human medicine, as well as evolutionary biology, and highlights the profound influence of artificial selection by humans on animal morphology, evolution, and welfare.

Published
2021

10. A Pliocene–Pleistocene continental biota from Venezuela

Author

CARRILLO-BRICEÑO, J. D., Sánchez, R., Scheyer, T. M., Carrillo, J. D., Delfino, M., Georgalis, G. L., Kerber, L., RUIZ-RAMONI, D., Birindelli, J. L. O., Cadena, E. A., Rincón, A. F., CHAVEZ-HOFFMEISTER, M., Carlini, A. A., Carvalho, M. R., TREJOS-TAMAYO, R., Vallejo, F., Jaramillo, C., JONES D. S., and SÁNCHEZ-VILLAGRA, M. R.

Published
2021

12. The anatomy, paleobiology, and evolutionary relationships of the largest extinct side-necked turtle

Author

Cadena, E-A; https://orcid.org/0000-0003-3038-567X, Scheyer, T M; https://orcid.org/0000-0002-6301-8983, Carrillo-Briceño, J D; https://orcid.org/0000-0002-8652-7692, Sánchez, R, Aguilera-Socorro, O A; https://orcid.org/0000-0003-4418-8351, Vanegas, A, Pardo, M; https://orcid.org/0000-0001-7313-1835, Hansen, D M; https://orcid.org/0000-0002-9584-2766, Sánchez-Villagra, M R; https://orcid.org/0000-0001-7587-3648, Cadena, E-A; https://orcid.org/0000-0003-3038-567X, Scheyer, T M; https://orcid.org/0000-0002-6301-8983, Carrillo-Briceño, J D; https://orcid.org/0000-0002-8652-7692, Sánchez, R, Aguilera-Socorro, O A; https://orcid.org/0000-0003-4418-8351, Vanegas, A, Pardo, M; https://orcid.org/0000-0001-7313-1835, Hansen, D M; https://orcid.org/0000-0002-9584-2766, and Sánchez-Villagra, M R; https://orcid.org/0000-0001-7587-3648

Abstract

Despite being among the largest turtles that ever lived, the biology and systematics of Stupendemys geographicus remain largely unknown because of scant, fragmentary finds. We describe exceptional specimens and new localities of S. geographicus from the Miocene of Venezuela and Colombia. We document the largest shell reported for any extant or extinct turtle, with a carapace length of 2.40 m and estimated mass of 1.145 kg, almost 100 times the size of its closest living relative, the Amazon river turtle Peltocephalus dumerilianus, and twice that of the largest extant turtle, the marine leatherback Dermochelys coriacea. The new specimens greatly increase knowledge of the biology and evolution of this iconic species. Our findings suggest the existence of a single giant turtle species across the northern Neotropics, but with two shell morphotypes, suggestive of sexual dimorphism. Bite marks and punctured bones indicate interactions with large caimans that also inhabited the northern Neotropics.

Published
2020

20. Evolutionary and developmental aspects of phalangeal formula variation in pig-nose and soft-shelled turtles (Carettochelyidae and Trionychidae)

Author

Delfino, M, Fritz, U, Sánchez-Villagra, M R, University of Zurich, and Delfino, M

Subjects
1105 Ecology, Evolution, Behavior and Systematics, 560 Fossils & prehistoric life, 10125 Paleontological Institute and Museum
Abstract

In order to examine the evolution of the phalangeal formula in a diverse clade of turtles, including hyperphalangy as a rare condition in this group, we studied 210 specimens representing all extant genera of Trionychidae and their sister taxon, Carettochelyidae. Both groups consist of highly aquatic species with elongated autopods that are either paddle-like (Trionychidae) or transformed to flippers (Carettochelyidae). Phalangeal formulae were obtained mostly by radiographs of alcohol-preserved or dry specimens, as well as by direct counts from skeletons. All trionychids and Carettochelys are pentadactylous, but their phalangeal formulae differ. Carettochelys exhibits the turtle-plesiomorphic state (manus and pes: 2-3-3-3-3), with no variation in adults. Trionychids exhibit intraspecific variation, ranging from 2-3-3-3-2 to 2-3-3-6-5 for the manus, and from 2-3-3-3-2 to 2-3-3-5-3 for the pes. The extant Carettochelys as well as the Middle Eocene Allaeochelys crassesculpta are characterized by an elongation of phalanges, whereas trionychids consistently have shorter phalanges. All trionychid genera exhibit some degree of hyperphalangy in digits IV and V, in both the manus and pes. Phalanges of the clawed digits I-III are very robust compared to phalanges of the non-clawed digits IV and V. The latter contribute significantly to the enlargement of the paddle by their additional phalanges. We hypothesize that this phalangeal pattern is coupled with prolongation of growth processes in the non-clawed digits. The differences in autopod morphology between carettochelyids and trionychids reflect different locomotor patterns related to different natural histories (elongated flippers for high-speed escape in the mainly herbivorous Carettochelys; broad paddles for rapid turns during hunting in the mainly carnivorous trionychids). The autopod of Pelodiscus sinensis is proposed as an experimental model to examine the developmental basis of adult autopod variation

Published
2018

23. Los Dugones de Urumaco

Author

Sánchez-Villagra, M R; https://orcid.org/0000-0001-7587-3648, Sánchez-Villagra, M R ( M R ), Koyabu, D, Sánchez, R, Sánchez-Villagra, M R; https://orcid.org/0000-0001-7587-3648, Sánchez-Villagra, M R ( M R ), Koyabu, D, and Sánchez, R

Published
2012

25. El Registro Fósil del Cenozoico

Author

Sánchez-Villagra, M R; https://orcid.org/0000-0001-7587-3648, Sánchez-Villagra, M R ( M R ), Horovitz, I, Sánchez-Villagra, M R; https://orcid.org/0000-0001-7587-3648, Sánchez-Villagra, M R ( M R ), and Horovitz, I

Published
2012

26. Los dinosaurios del Táchira

Author

Sánchez-Villagra, M R; https://orcid.org/0000-0001-7587-3648, Sánchez-Villagra, M R ( M R ), Barrett, P M, Sánchez-Villagra, M R; https://orcid.org/0000-0001-7587-3648, Sánchez-Villagra, M R ( M R ), and Barrett, P M

Published
2012

27. Los Cefalópodos Fósiles de Venezuela

Author

Sánchez-Villagra, M R; https://orcid.org/0000-0001-7587-3648, Sánchez-Villagra, M R ( M R ), Klug, C, Etter, W, Sánchez-Villagra, M R; https://orcid.org/0000-0001-7587-3648, Sánchez-Villagra, M R ( M R ), Klug, C, and Etter, W

Published
2012

28. Diversidad y Gigantismo en los Cocodrilos Fósiles

Author

Sánchez-Villagra, M R; https://orcid.org/0000-0001-7587-3648, Sánchez-Villagra, M R ( M R ), Scheyer, T M, Sánchez-Villagra, M R; https://orcid.org/0000-0001-7587-3648, Sánchez-Villagra, M R ( M R ), and Scheyer, T M

Published
2012

30. Fossil turtles from the northern neotropics: the Urumaco sequence fauna and finds from other localities in Venezuela and Colombia

Author

Sánchez-Villagra, M R; https://orcid.org/0000-0001-7587-3648, Aguilera, O A, Carlini, A A, Sánchez-Villagra, M R ( M R ), Aguilera, O A ( O A ), Carlini, A A ( A A ), Scheyer, T M, Sánchez-Villagra, M R; https://orcid.org/0000-0001-7587-3648, Aguilera, O A, Carlini, A A, Sánchez-Villagra, M R ( M R ), Aguilera, O A ( O A ), Carlini, A A ( A A ), and Scheyer, T M

Published
2010

31. Venezuelan geography and biodiversity: a brief introduction

Author

Sánchez-Villagra, M R; https://orcid.org/0000-0001-7587-3648, Aguilera, O A, Carlini, A A, Sánchez-Villagra, M R ( M R ), Aguilera, O A ( O A ), Carlini, A A ( A A ), Villalba, C, Sánchez-Villagra, M R; https://orcid.org/0000-0001-7587-3648, Aguilera, O A, Carlini, A A, Sánchez-Villagra, M R ( M R ), Aguilera, O A ( O A ), Carlini, A A ( A A ), and Villalba, C

Published
2010

32. The fossil vertebrate record of Venezuela of the last 65 million years

Author

Sánchez-Villagra, M R; https://orcid.org/0000-0001-7587-3648, Aguilera, O A, Carlini, A A, Sánchez-Villagra, M R ( M R ), Aguilera, O A ( O A ), Carlini, A A ( A A ), Sánchez, R, Sánchez-Villagra, M R; https://orcid.org/0000-0001-7587-3648, Aguilera, O A, Carlini, A A, Sánchez-Villagra, M R ( M R ), Aguilera, O A ( O A ), Carlini, A A ( A A ), and Sánchez, R

Published
2010

33. Mesozoic and Cenozoic decapod crustaceans from Venezuela and related trace-fossil assemblages

Author

Sánchez-Villagra, M R; https://orcid.org/0000-0001-7587-3648, Aguilera, O A, Carlini, A A, Sánchez-Villagra, M R ( M R ), Aguilera, O A ( O A ), Carlini, A A ( A A ), Aguilera, O, Rodrigues de Aguilera, D, Vega, F J, Sánchez-Villagra, M R; https://orcid.org/0000-0001-7587-3648, Aguilera, O A, Carlini, A A, Sánchez-Villagra, M R ( M R ), Aguilera, O A ( O A ), Carlini, A A ( A A ), Aguilera, O, Rodrigues de Aguilera, D, and Vega, F J

Published
2010

34. Fossil crocodylians from Venezuela in the context of South American faunas

Author

Sánchez-Villagra, M R; https://orcid.org/0000-0001-7587-3648, Aguilera, O A, Carlini, A A, Sánchez-Villagra, M R ( M R ), Aguilera, O A ( O A ), Carlini, A A ( A A ), Scheyer, T M, Moreno-Bernal, J W, Sánchez-Villagra, M R; https://orcid.org/0000-0001-7587-3648, Aguilera, O A, Carlini, A A, Sánchez-Villagra, M R ( M R ), Aguilera, O A ( O A ), Carlini, A A ( A A ), Scheyer, T M, and Moreno-Bernal, J W

Published
2010

35. A short history of the study of Venezuelan vertebrate fossils

Author

Sánchez-Villagra, M R; https://orcid.org/0000-0001-7587-3648, Aguilera, O A, Carlini, A A, Sánchez-Villagra, M R ( M R ), Aguilera, O A ( O A ), Carlini, A A ( A A ), Sánchez-Villagra, M R; https://orcid.org/0000-0001-7587-3648, Aguilera, O A, Carlini, A A, Sánchez-Villagra, M R ( M R ), Aguilera, O A ( O A ), and Carlini, A A ( A A )

Published
2010

36. Fossil rodents from the Late Miocene Urumaco and Middle Miocene Cumaca foramtions, Venezuela

Author

Sánchez-Villagra, M R; https://orcid.org/0000-0001-7587-3648, Aguilera, O A, Carlini, A A, Sánchez-Villagra, M R ( M R ), Aguilera, O A ( O A ), Carlini, A A ( A A ), Horovitz, I, Sánchez-Villagra, M R; https://orcid.org/0000-0001-7587-3648, Aguilera, O A, Carlini, A A, Sánchez-Villagra, M R ( M R ), Aguilera, O A ( O A ), Carlini, A A ( A A ), and Horovitz, I

Published
2010

37. Developmental vertebrate palaeontology

Author

Sánchez-Villagra, M R; https://orcid.org/0000-0001-7587-3648, Sánchez-Villagra, M R ( M R ), Sánchez-Villagra, M R; https://orcid.org/0000-0001-7587-3648, and Sánchez-Villagra, M R ( M R )

Published
2010

39. Los dinosaurios del Táchira

Author

Barrett, P M, Sánchez-Villagra, M R, University of Zurich, and Sánchez-Villagra, M R

Subjects
560 Fossils & prehistoric life, 10125 Paleontological Institute and Museum
Published
2012

41. El Registro Fósil del Cenozoico

Author

Horovitz, I, Sánchez-Villagra, M R, University of Zurich, and Sánchez-Villagra, M R

Subjects
560 Fossils & prehistoric life, 10125 Paleontological Institute and Museum
Published
2012

43. Circumventing the polydactyly ‘constraint’: the mole's ‘thumb’

Author

Mitgutsch, C, Richardson, M K, Jiménez, R, Martin, J E, Kondrashov, P, De Bakker, M A G, Sánchez-Villagra, M R, University of Zurich, and Sánchez-Villagra, M R

Subjects
560 Fossils & prehistoric life, autopodial development, 1101 Agricultural and Biological Sciences (miscellaneous), os falciforme, 1100 General Agricultural and Biological Sciences, 10125 Paleontological Institute and Museum, Talpidae
Published
2012

44. 'Missing links' - Zeugnisse der Evolution

Author

Sánchez-Villagra, M R, University of Zurich, Reyer, H U, Schmid-Hempel, P, and Sánchez-Villagra, M R

Subjects
560 Fossils & prehistoric life, 10125 Paleontological Institute and Museum
Published
2011

46. Developmental palaeontology in synapsids: the fossil record of ontogeny in mammals and their closest relatives

Author

Sánchez-Villagra, M R, University of Zurich, and Sánchez-Villagra, M R

Subjects
2300 General Environmental Science, 560 Fossils & prehistoric life, skeletochronology, 1300 General Biochemistry, Genetics and Molecular Biology, 2400 General Immunology and Microbiology, growth, heterochrony, allometry, 1100 General Agricultural and Biological Sciences, 10125 Paleontological Institute and Museum, modularity, palaeohistology
Published
2010
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47. Venezuelan geography and biodiversity: a brief introduction

Author

Villalba, C, Sánchez-Villagra, M R, University of Zurich, Sánchez-Villagra, M R, Aguilera, O A, and Carlini, A A

Subjects
560 Fossils & prehistoric life, 10125 Paleontological Institute and Museum, 3300 General Social Sciences
Published
2010

49. A short history of the study of Venezuelan vertebrate fossils

Author

Sánchez-Villagra, M R, University of Zurich, Sánchez-Villagra, M R, Aguilera, O A, and Carlini, A A

Subjects
560 Fossils & prehistoric life, 10125 Paleontological Institute and Museum, 3300 General Social Sciences
Published
2010

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