Annie Schmaltz Hsiou
Current Organizations / Institutes
The organizations/institutes from the scholar's latest article
Previous Organizations / Institutes
The organizations / institutes from the scholar's other articles in the past ten years
Research Subjects
Research Interests
Annie Schmaltz Hsiou has a total of 211 co-authors. Here are the top co-authors by number of shared publications:
- Giovanne Mendes Cidade
Universidade de São Paulo
9 shared publications - Silvio Onary
Laboratório de Paleontologia, Faculdade de Filosofia Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
8 shared publications - Douglas Riff
Instituto de Biologia, Universidade Federal de Uberlândia, Uberlândia, Minas Gerais, Brazil
7 shared publications - Edson Guilherme
Universidade Federal do Acre
5 shared publications - Leonardo Kerber
Centro de Apoio à Pesquisa Paleontológica Universidade Federal de Santa Maria São João do Polêsine Brazil
5 shared publications - Agustin Guillermo Martinelli
Sección Paleontología de Vertebrados, CONICET—Museo Argentino de Ciencias Naturales Bernardino Rivadavia, Buenos Aires, Argentina
4 shared publications
Latest Publications
- Open Access
- 7 October 2026
- Published by Elsevier in Journal of South American Earth Sciences
- Vol. 185
Chronostratigraphy of the southwestern Amazon: New U-Pb ages for Neogene deposits in the upper Acre River
- 7 October 2026
- Published by Elsevier in Journal of South American Earth Sciences
- Vol. 185
Open AccessChronostratigraphy of the southwestern Amazon: New U-Pb ages for Neogene deposits in the upper Acre River
- 28 July 2026
- Published by Springer Nature in Journal of Mammalian Evolution
- Vol. 33 (3) , 38
New records of platyrrhine primates (Atelidae and Cebidae) from the Miocene of Western Amazonia, State of Acre, Brazil
- 28 July 2026
- Published by Springer Nature in Journal of Mammalian Evolution
- Vol. 33 (3) , 38
New records of platyrrhine primates (Atelidae and Cebidae) from the Miocene of Western Amazonia, State of Acre, Brazil
- Open Access
- 22 July 2026
- Published by Springer Nature in Nature
- Vol. 657 (8130) , 170-178
Exceptional brain and ecological diversity in the earliest snakes
- 22 July 2026
- Published by Springer Nature in Nature
- Vol. 657 (8130) , 170-178
Open AccessExceptional brain and ecological diversity in the earliest snakes
- Open Access
- 26 December 2025
- Published by Sociedade Brasileira de Paleontologia in Revista Brasileira de Paleontologia
- Vol. 28 (3) , e20250511
A look into the gender demographics of Brazilian Paleontology
In 2020, a group of Brazilian female paleontologists from various universities and public institutions conducted the study “Brazilian Paleontology Gender Profile,” whose main objective was to assess the current demographic diversity of Brazilian paleontologists and how the role of women has evolved throughout the history of the Brazilian Society of Paleontology. Initially, the project aimed to determine the number of professionals working in Paleontology and their demographic distribution in the country. However, our research expanded, encompassing race, Indigenous representation, LGBTQIAP+ data, parenthood, harassment, and gender violence. The present work presents the first installment of three sets of unpublished data, shedding light on gender issues and how to combat gender discrimination through the proposal of affirmative action policies that could be taken within the Brazilian Society of Paleontology and other scientific associations in South America. Keywords: gender profile, women in science, gender biases.
- 26 December 2025
- Published by Sociedade Brasileira de Paleontologia in Revista Brasileira de Paleontologia
- Vol. 28 (3) , e20250511
Open AccessA look into the gender demographics of Brazilian Paleontology
In 2020, a group of Brazilian female paleontologists from various universities and public institutions conducted the study “Brazilian Paleontology Gender Profile,” whose main objective was to assess the current demographic diversity of Brazilian paleontologists and how the role of women has evolved throughout the history of the Brazilian Society of Paleontology. Initially, the project aimed to determine the number of professionals working in Paleontology and their demographic distribution in the country. However, our research expanded, encompassing race, Indigenous representation, LGBTQIAP+ data, parenthood, harassment, and gender violence. The present work presents the first installment of three sets of unpublished data, shedding light on gender issues and how to combat gender discrimination through the proposal of affirmative action policies that could be taken within the Brazilian Society of Paleontology and other scientific associations in South America. Keywords: gender profile, women in science, gender biases.
- 1 October 2023
- Published by Wiley in The Anatomical Record
- Vol. 307 (6) , 2047-2064
New fossil anhingids from the upper Acre River (Late Miocene of southwestern Amazon)
Four extant species of anhingids are found worldwide, all belonging to a single genus (Anhinga). However, the fossil record reveals a much greater diversity of this group in the past. The oldest known anhingids date back to the upper Oligocene period in Australia, but during the Miocene epoch in South America, they achieved their most remarkable diversity. This study describes newly discovered anhingid fossils from the Late Miocene period in South America. These fossils were extracted from the Acre conglomerate member, part of the Upper Miocene deposits in the southwestern Amazon region. The described fossils consist of two fragments of pelvic girdles, two femora, and two vertebrae belonging to a giant anhingid (Macranhinga sp.), as well as a vertebra from Anhinga minuta, the smallest of all darters. The examination of these fossils suggests the presence of potentially three distinct anhingid taxa within the same locality. The environment in which the conglomerate deposits were formed was ecologically complex. It is likely that these three species coexisted within the same ecosystem but avoided direct competition for food and reproductive sites by not fully exploiting their fundamental niche.
- 1 October 2023
- Published by Wiley in The Anatomical Record
- Vol. 307 (6) , 2047-2064
New fossil anhingids from the upper Acre River (Late Miocene of southwestern Amazon)
Four extant species of anhingids are found worldwide, all belonging to a single genus (Anhinga). However, the fossil record reveals a much greater diversity of this group in the past. The oldest known anhingids date back to the upper Oligocene period in Australia, but during the Miocene epoch in South America, they achieved their most remarkable diversity. This study describes newly discovered anhingid fossils from the Late Miocene period in South America. These fossils were extracted from the Acre conglomerate member, part of the Upper Miocene deposits in the southwestern Amazon region. The described fossils consist of two fragments of pelvic girdles, two femora, and two vertebrae belonging to a giant anhingid (Macranhinga sp.), as well as a vertebra from Anhinga minuta, the smallest of all darters. The examination of these fossils suggests the presence of potentially three distinct anhingid taxa within the same locality. The environment in which the conglomerate deposits were formed was ecologically complex. It is likely that these three species coexisted within the same ecosystem but avoided direct competition for food and reproductive sites by not fully exploiting their fundamental niche.
- Open Access
- 3 July 2023
- Published by National Academy of Sciences in Proceedings of the National Academy of Sciences
- Vol. 120 (28)
An eosimiid primate of South Asian affinities in the Paleogene of Western Amazonia and the origin of New World monkeys
Recent fossil discoveries in Western Amazonia revealed that two distinct anthropoid primate clades of African origin colonized South America near the Eocene/Oligocene transition ( ca. 34 Ma). Here, we describe a diminutive fossil primate from Brazilian Amazonia and suggest that, surprisingly, a third clade of anthropoids was involved in the Paleogene colonization of South America by primates. This new taxon, Ashaninkacebus simpsoni gen. et sp. nov., has strong dental affinities with Asian African stem anthropoids: the Eosimiiformes. Morphology-based phylogenetic analyses of early Old World anthropoids and extinct and extant New World monkeys (platyrrhines) support relationships of both Ashaninkacebus and Amamria (late middle Eocene, North Africa) to the South Asian Eosimiidae. Afro-Arabia, then a mega island, played the role of a biogeographic stopover between South Asia and South America for anthropoid primates and hystricognathous rodents. The earliest primates from South America bear little adaptive resemblance to later Oligocene-early Miocene platyrrhine monkeys, and the scarcity of available paleontological data precludes elucidating firmly their affinities with or within Platyrrhini. Nonetheless, these data shed light on some of their life history traits, revealing a particularly small body size and a diet consisting primarily of insects and possibly fruit, which would have increased their chances of survival on a natural floating island during this extraordinary over-water trip to South America from Africa. Divergence-time estimates between Old and New World taxa indicate that the transatlantic dispersal(s) could source in the intense flooding events associated with the late middle Eocene climatic optimum (ca. 40.5 Ma) in Western Africa.
- 3 July 2023
- Published by National Academy of Sciences in Proceedings of the National Academy of Sciences
- Vol. 120 (28)
Open AccessAn eosimiid primate of South Asian affinities in the Paleogene of Western Amazonia and the origin of New World monkeys
Recent fossil discoveries in Western Amazonia revealed that two distinct anthropoid primate clades of African origin colonized South America near the Eocene/Oligocene transition ( ca. 34 Ma). Here, we describe a diminutive fossil primate from Brazilian Amazonia and suggest that, surprisingly, a third clade of anthropoids was involved in the Paleogene colonization of South America by primates. This new taxon, Ashaninkacebus simpsoni gen. et sp. nov., has strong dental affinities with Asian African stem anthropoids: the Eosimiiformes. Morphology-based phylogenetic analyses of early Old World anthropoids and extinct and extant New World monkeys (platyrrhines) support relationships of both Ashaninkacebus and Amamria (late middle Eocene, North Africa) to the South Asian Eosimiidae. Afro-Arabia, then a mega island, played the role of a biogeographic stopover between South Asia and South America for anthropoid primates and hystricognathous rodents. The earliest primates from South America bear little adaptive resemblance to later Oligocene-early Miocene platyrrhine monkeys, and the scarcity of available paleontological data precludes elucidating firmly their affinities with or within Platyrrhini. Nonetheless, these data shed light on some of their life history traits, revealing a particularly small body size and a diet consisting primarily of insects and possibly fruit, which would have increased their chances of survival on a natural floating island during this extraordinary over-water trip to South America from Africa. Divergence-time estimates between Old and New World taxa indicate that the transatlantic dispersal(s) could source in the intense flooding events associated with the late middle Eocene climatic optimum (ca. 40.5 Ma) in Western Africa.
- 11 May 2023
- Published by Centre National de la Recherche Scientifique - Institut des Sciences de l'Evolution de Montpellier in MorphoMuseuM
- Vol. 9 (2) , e185
3D models related to the publication: Virtual endocasts of Clevosaurus brasiliensis and the tuatara: rhynchocephalian neuroanatomy and the oldest endocranial record for Lepidosauria
- 11 May 2023
- Published by Centre National de la Recherche Scientifique - Institut des Sciences de l'Evolution de Montpellier in MorphoMuseuM
- Vol. 9 (2) , e185
3D models related to the publication: Virtual endocasts of Clevosaurus brasiliensis and the tuatara: rhynchocephalian neuroanatomy and the oldest endocranial record for Lepidosauria
- 23 March 2023
- Published by Wiley in The Anatomical Record
- Vol. 307 (4) , 1366-1389
Virtual endocasts of Clevosaurus brasiliensis and the tuatara: Rhynchocephalian neuroanatomy and the oldest endocranial record for Lepidosauria
Understanding the origins of the vertebrate brain is fundamental for uncovering evolutionary patterns in neuroanatomy. Regarding extinct species, the anatomy of the brain and other soft tissues housed in endocranial spaces can be approximated by casts of these cavities (endocasts). The neuroanatomical knowledge of Rhynchocephalia, a reptilian clade exceptionally diverse in the early Mesozoic, is restricted to the brain of its only living relative, Sphenodon punctatus, and unknown for fossil species. Here, we describe the endocast and the reptilian encephalization quotient (REQ) of the Triassic rhynchocephalian Clevosaurus brasiliensis and compare it with an ontogenetic series of S. punctatus. To better understand the informative potential of endocasts in Rhynchocephalia, we also examine the brain‐endocast relationship in S. punctatus. We found that the brain occupies 30% of its cavity, but the latter recovers the general shape and length of the brain. The REQ of C. brasiliensis (0.27) is much lower than S. punctatus (0.84–1.16), with the tuatara being close to the mean for non‐avian reptiles. The endocast of S. punctatus is dorsoventrally flexed and becomes more elongated throughout ontogeny. The endocast of C. brasiliensis is mostly unflexed and tubular, possibly representing a more plesiomorphic anatomy in relation to S. punctatus. Given the small size of C. brasiliensis, the main differences may result from allometric and heterochronic phenomena, consistent with suggestions that S. punctatus shows peramorphic anatomy compared to Mesozoic rhynchocephalians. Our results highlight a previously undocumented anatomical diversity among rhynchocephalians and provide a framework for future neuroanatomical comparisons among lepidosaurs.
- 23 March 2023
- Published by Wiley in The Anatomical Record
- Vol. 307 (4) , 1366-1389
Virtual endocasts of Clevosaurus brasiliensis and the tuatara: Rhynchocephalian neuroanatomy and the oldest endocranial record for Lepidosauria
Understanding the origins of the vertebrate brain is fundamental for uncovering evolutionary patterns in neuroanatomy. Regarding extinct species, the anatomy of the brain and other soft tissues housed in endocranial spaces can be approximated by casts of these cavities (endocasts). The neuroanatomical knowledge of Rhynchocephalia, a reptilian clade exceptionally diverse in the early Mesozoic, is restricted to the brain of its only living relative, Sphenodon punctatus, and unknown for fossil species. Here, we describe the endocast and the reptilian encephalization quotient (REQ) of the Triassic rhynchocephalian Clevosaurus brasiliensis and compare it with an ontogenetic series of S. punctatus. To better understand the informative potential of endocasts in Rhynchocephalia, we also examine the brain‐endocast relationship in S. punctatus. We found that the brain occupies 30% of its cavity, but the latter recovers the general shape and length of the brain. The REQ of C. brasiliensis (0.27) is much lower than S. punctatus (0.84–1.16), with the tuatara being close to the mean for non‐avian reptiles. The endocast of S. punctatus is dorsoventrally flexed and becomes more elongated throughout ontogeny. The endocast of C. brasiliensis is mostly unflexed and tubular, possibly representing a more plesiomorphic anatomy in relation to S. punctatus. Given the small size of C. brasiliensis, the main differences may result from allometric and heterochronic phenomena, consistent with suggestions that S. punctatus shows peramorphic anatomy compared to Mesozoic rhynchocephalians. Our results highlight a previously undocumented anatomical diversity among rhynchocephalians and provide a framework for future neuroanatomical comparisons among lepidosaurs.