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Un nuevo Caiman (Crocodylia, Alligatoridae) de la Formatión Tremembé (Oligoceno), Estado de São Paulo, Brasil, y su significado paleoclimático
... The amphibian group is represented by a caecilian specimen of the family Typhlonectidae and by two anurans, one assigned to the Pipidae family and the other identified as belonging to the Hyloidea (= Bufonoidea) superfamily, having osteological characteristics common to the families Leptodactylidae and Hylidae (Riff & Bergqvist, 1999, Campo et al., 2016, Santos, 2020, Santos et al., 2024. Species of the orders Crocodylia, Squamata and Testudines represent the reptiles found in bentonite clay and pyrobituminous shale (Chiappe, 1988, Kischlat, 1993, Capilla, 1994. ...
Introduction. The Tremembé Formation (Oligocene), outcropping in the eastern region of the São Paulo State, Brazil, is the most richly fossiliferous lithostratigraphic unit in the Taubaté Basin, providing numerous records of a diverse flora and fauna from the Paleogene that inhabited the Paraíba Valley. Objective. This paper aims to provide an updated checklist of all groups of invertebrates and vertebrates that have been described based on fossils recovered from this geological formation in the last centuries. Methodology. A bibliographic survey was carried out in four different databases. Results. Over a hundred taxa were reported in the references analyzed, including porifers, nematodes, molluscs, annelids, arthropods, fishes, amphibians, reptiles, birds and mammals. Some invertebrate groups have a remarkable diversity like the paleo-fauna of arthropods. Furthermore, birds and mammals represent most of the taxonomic richness of vertebrates from the Tremembé Formation. Conclusion. The faunistic diversity of the Tremembé Formation, described throughout the 20th and 21st centuries, reveals the potential of paleontological discoveries in this geological area and its importance to the Oligocene Brazilian fossil record, providing support for dating processes and correlation with other fossiliferous localities.
... Fragmentary material of Purussaurus sp. is dated as old as the late Oligocene (Antoine et al. 2016;Solórzano et al. 2018); however, new fossil discoveries are needed in order to provide additional morphological evidence for the identification of Purussaurus sp. in late Oligocene rocks. The late Oligocene 'Caiman' tremembensis from the Tremembé Formation of Brazil, represented by a fragmentary dentary (Chiappe 1988) does show a splenial excluded from the mandibular symphysis with its anterior tip passing dorsal to the Meckelian groove, but this character may not diagnose the crown alone, as it is also present in taxa usually associated with stem-Caimaninae (e.g., Eocaiman spp., Ne. ionensis; Fortier et al. 2014). ...
An incomplete fossil record and unstable phylogenies of extinct taxa hamper reconstructing the early evolution of Caimaninae. We describe previously unpublished articulated fossils of a key species, Tsoabichi greenriverensis from the early Eocene Green River Formation of North America, exhibiting further character evidence for the caimanine affinities of this taxon. Parsimony analysis of modified morphological taxon-character datasets coupled with a critical review of character evolution and published phylogenies reveals that fossil evidence for Palaeogene crown group and Late Cretaceous total-group representatives is unreliable due to uncertain character evolution in early Alligatoridae. The earliest unambiguous fossil age for total and crown-group Caimaninae are 63.5 Ma and 18.06 Ma, respectively. These calibration points follow best practices and are vital for better constrained estimates of time calibrated analyses. Phylogeny continues to imply two separate Caimaninae dispersals between North and South America, but instead of a northward back-dispersal, we find two Palaeogene dispersals to South America an equally likely hypothesis. Miocene taxa of Central America previously assigned to the stem lineage ancestral to South American Caimaninae are reinterpreted as part of a Neogene northward expansion of the crown group.
... El registro más antiguo de un aligatórido descrito en América del Sur es de Eocaiman cavernensis del Eoceno temprano (hace 56 -34 millones de años) en la provincia de Chubut, Argentina; la presencia de este reptil también se ha reportado para Brasil (Chiappe, 1988 Frente a las amenazas indirectas, este grupo ha sido y es, gravemente afectado por la destrucción del hábitat, la cual es una de las causas principales de la disminución poblacional. Los humedales se encuentran entre los ecosistemas más amenazados a nivel mundial y se estima que se ha perdido cerca del 50% en el planeta en el último siglo a causa de la irrigación para agricultura, desarrollo urbano y sistemas de regulación de agua (Shine & de Klemm, 1999 (Medem, 1981;Ross, 1969 En la actualidad las babillas obtenidas de zoocriaderos proporcionan la mayor cantidad de pieles de crocodylianos para los mercados internacionales (Macgregor, 2006 la teoría evolutiva moderna, y su aporte a la biología de la conservación ha ido creciendo conforme su teoría y práctica han ido integrándose en la disciplina que ahora se conoce como Genética de la Conservación. ...
Históricamente el orden Crocodylia ha sido objeto de sobreexplotación; de las pieles de estas especies comercializadas a nivel mundial un alto porcentaje pertenecen a Caiman crocodilus, siendo Colombia su principal exportador. La legislación colombiana estableció una cuota de repoblación por la cual los zoocriaderos deben liberar un porcentaje de su producción como contribución a la conservación de la especie. Sin embargo, la falta de conocimiento de la composición genética de las poblaciones naturales ha impedido esta labor. Debido a la presencia de grandes poblaciones en el Tolima y que a la fecha no se cuenta con estudios genéticos para la especie en la región, se planteó una caracterización genética de sus poblaciones.
Se analizaron los genes mitocondriales COI y CytB para cuantificar su variabilidad genética, diferenciación poblacional, historia demográfica y estructura genética. Adicionalmente se utilizaron secuencias depositadas en bases de datos, así como nuevas secuencias para definir sus relaciones filogenéticas y filogeográficas. Como resultado, se identificaron 12 haplotipos para el Tolima, altos valores de diversidad genética, una fuerte diferenciación poblacional y nula evidencia de expansiones o disminuciones poblacionales. Los análisis filogenéticos y filogeográficos identifican a las poblaciones del Tolima dentro de un linaje distribuido desde el sur de Costa Rica hasta el Tolima y muestra una alta diferenciación con las poblaciones Cis-andinas. Estos resultados muestran que la diversidad genética debería ser tomada en cuenta a la hora de realizar cualquier tipo de translocación, ya que podría afectarse la integridad haplotípica y la estructura natural histórica de las poblaciones del departamento.
... Besides dyrosaurids that apparently did not surpass the Paleocene-Eocene boundary in South America (Hastings et al, 2014), the other Cenozoic mesoeucrocodylian clades were either originated within the Americas during the Mesozoic times (i.e., caimanines : Brochu, 1999;sebecids: Pol & Powell, 2011) or incorporated to the South American and Caribbean faunas later by some kind of dispersal during Paleogene times (i.e., gavialoids: Vélez-Juarbe et al., 2007). (Hastings et al., 2010); El Gauchito (Bona, 2007); Itaboraí (Pinheiro, 2012); Jujui (Gasparini, 1984); Tiupampa (Buffetaut, 1991); Salta (Gasparini, 1986); Contamana (Salas-Gismondi et al., 2013;Antoine et al., submitted); Paracas ; Mendoza (Rusconi, 1946); Río Loro (Pol & Powel, 2011); Puerto Visser (Rusconi, 1937); Colhué Huapí (Simpson, 1933); Taubaté (Chiappe, 1988); Neogene: Contamana (Antoine et al., submitted); La Venta (Langston, 1965); Iquitos ; Nueva Unión (Salas-Gismondi et al., 2015); Fitzcarrald ; Yuruá, (Price, 1964); Acre (Cozzuol, 2006); Urumaco (Sánchez-Villagra & ; Palo Pintado (Bona et al., 2014); Yecua (Tineo et al., 2014); Bahía Inglesa (Walsh & Suárez, 2005); Sacaco (Kraus, 1997); El Breal (Fortier & Rincón, 2013). Bigger dots represent the record of mesoeucrocodylian assemblages within those localities. ...
Under the influential role of the Andean range, western Amazonia developed distinctive environmental conditions that ultimately led to divergent, higher biodiversity within the Neotropics. Although this intimate geologic-biotic interaction might have produced similar phenomena in the past, our knowledge about the tropical biotic evolution occurring in close proximity to these rapid growing mountains is poorly documented in the deep time. A pivotal time interval for the emergence of the modern Amazonian ecosystems occurred during the Miocene, when major Andean uplift remodeled the landscape of the foreland basin and fostered the onset of the Amazon River System, at about 10.5 million years ago. Proto-Amazonian biotas just prior to this episode are integral to understanding origins of Neotropical biodiversity, yet vertebrate fossil evidence was extraordinarily rare thus far. By studying the evolution, ecology, and biogeography of fossil mesoeucrocodylians (caimans, gharials, and sebecids) documented in new rich paleontological sites of eastern Peru, this research provides a snapshot of the florishing Miocene life of western proto-Amazonia. The crocodylian assemblage of the Iquitos bonebeds (middle-late Miocene transition) is extraordinary in representing both the highest taxonomic diversity (with up to seven associated species) and the widest range of snout morphotypes ever recorded in any crocodyliform community, recent or extinct. The heterogeneity of snout shapes at the Peruvian Miocene localities covers most of the morphospace range known for the entire crocodyliform clade reflecting the combined influences of long-term evolution, resource abundance and variety, and niche partitioning in a complex ecosystem, with no recent equivalent. Besides the large-bodied Purussaurus and Mourasuchus, all other crocodylians in Iquitos are new taxa, including a stem caiman—Gnatusuchus pebasensis—bearing a massive shovel-shaped mandible, procumbent anterior and globular posterior teeth, and a mammal-like diastema. This unusual species is an extreme exemplar of a radiation of small caimans with crushing dentitions recording peculiar feeding strategies correlated with a peak in proto-Amazonian molluscan diversity and abundance, deep in the so-called Pebas Mega-Wetland System. The sole long-snouted crocodylian in this community is the basalmost gavialoid of the Amazonian basin, a critical taxon that offers evidence for accurately reconstructing the ancestral anatomy and ecology of this clade. Including this new species in phylogenetic-morphometric analyses suggests that the evolution of the similar rostral pattern between South American and Indian gavialoids results from parallel evolution in riverine habitats. As part of the same prevailing Pebas biome, Fitzcarrald localities correspond to coeval paleoenvironments closer to the Andean influence (13-12 Ma). This fauna includes deep-snouted sebecids (Sebecosuchia) and advanced gavialoids (Gavialoidea) with protruding eyes, associated with a wide array of caimans (Mourasuchus, Purussaurus, Paleosuchus et Eocaiman), and further suggesting the presence of terrestrial settings and fluvially-dominated ecosystems. On the other hand, the highly endemic Iquitos faunas evolved within the dysoxic marshes and swamps typical of the long-lived Pebas Mega-Wetland System (early–early late Miocene) and declined with the inception of the transcontinental Amazon drainage, favoring diversification of longirostrine crocodylians and more modern generalist-feeding caimans. Indeed, the end of the Pebas Mega-Wetland System notably resulted in the reduction of the phylogenetic and morphotypical mesoeucrocodylian proto-Amazonian diversity, designating the beginning of the modern Amazonian faunas. The rise and demise of distinctive, highly productive aquatic ecosystems substantially influenced evolution of Amazonian biodiversity hotspots of crocodylians and other organisms throughout the Neogene.
... The fine sediments of the Trememb e Formation were laid down in a swampy lake surrounded by a rich vegetation (Duarte & Mardarim-de-Lacerda, 1992;Mandarim-de-Lacerda and Bernardes-de-Oliveira, 1999;Veiga, 2009). The biota is represented by diversified fossils of mammals, reptiles, birds, fishes, arthropods, plants and several types of ichnotaxons (Ferreira, 1974;Fernandes et al., 1987;Chiappe, 1988;Carvalho and Fernandes, 1989;Martins-Neto, 1998;Malabarba, 2000;Bernardes-de-oliveira et al., 2002aBernardes-de-oliveira et al., , 2002bOlson and Alvarenga, 2002;Melo et al., 2007;Veiga, 2009;Ribeiro, 2010;Mayr et al., 2011a;Bergue et al., 2015aBergue et al., , 2015b. While younger in age, the high quality of its fossils is comparable to the Eocene Messel Shale Pit fossils (Franzen, 1985), as soft tissues of different groups of organisms, such as plants and vertebrates, were exquisitely preserved (Prado et al., 2015). ...
Feathers are rare in the fossil record because they have a low fossilization potential. Despite their palaeobiological significance, they also provide important palaeoecological and taphonomic information. Here, we report a new occurrence of three isolated feathers from the shales of the Oligocene Tremembé Formation (Taubaté Basin, SE Brazil). Their possible taxonomic affinities and taphonomic features are also discussed. Analyses identified the specimens as representatives of two pennaceous morphotypes (i.e., a contour and a rectrice feather). Both are preserved as carbonized traces, although, due taphonomic processes, they show different degrees of preservation. Since the Tremembé Formation is responsible for the most diverse record of Cenozoic birds, and because water-adapted birds (e.g., anseriformes and phoenicopteriformes) occur in this unit, it is highly possible that these feathers belonged to these aquatic taxa. Further investigations should concentrate on geochemical and microscopic techniques in order to reveal additional taxonomic and paleoecological features currently unknown in Paleogene birds of Brazil.
... La especie C. tremembensis Chiappe, 1988, del Oligoceno de la Formación Tremembé (estado de São Paulo, Brasil), es considerada un nomen dubium (Fortier et al., en prensa). También del Mioceno medio del Arco de Fitzcarraldo (Perú) provienen restos asignados a Caiman sp. ...
This paper describes the remains of an alligatorid from levels of the Piquete Formation (Pliocene-early Pleistocene) of Rosario de la Frontera, southern of Salta province, Argentina. The specimen is referred to the species Caiman latirostris (Daudin, 1802) based on their morphology. The results of a phylogenetic analysis suggest a close relationship with species bearing a prominent rostral ridge of the genus Caiman Spix, 1825-The validity of other remains assigned to the species is discussed, constituting this record the most complete and best preserved. Based on the ecological requirements of C. latirostris paleoenvironmental interpretations are made by analogy with the currently inhabited environment of this taxon.
... pers.). Con respecto a los Crocodylia, el registro más antiguo para el género viviente Caiman lo constituye la especie extinta C. tremembensis, conocida por restos procedentes del Oligoceno (Formación Tremembé) de la localidad Padre Eterno, Brasil (Chiappe, 1988). Adicionalmente, numerosos hallazgos indican la existencia de los géneros actuales Melanosuchus y Caiman para el Mioceno Medio-Superior de diversas localidades de Venezuela, Brasil y Argentina (Langston, 1965; Langston & Gasparini, 1997; Gasparini, 1996; Brochu, 1999; Piña & Argañaraz, 2000 ), registrándose incluso especímenes que han sido referidos a las especies vivientes C. yacare y C. latirostris exhumados en el Mioceno de Argentina (Gasparini, 1981Gasparini, , 1996 ). ...
New fossil specimens of amphibians and reptiles found in several localities of the Cerro Azul Formation (Upper Miocene) from La Pampa province are described. The new records include a fragmentary skull remain assigned to the frog genus Ceratophrys, carapace fragments of the tortoise genus Chelonoidis, vertebrae referred to the lizard Tupinambis, and a trunk vertebra of a colubroid snake compared with the living colubroid genus Philodryas. Previous Tertiary records of genera of amphibians and reptiles, as well as the studied assemblage from the Upper Miocene of La Pampa, indicate that almost the modern genera that conform the Neotropical herpetofauna were well in progress by the Miocene, a similar pattern observed in other parts of the world.
... pers.). Con respecto a los Crocodylia, el registro más antiguo para el género viviente Caiman lo constituye la especie extinta C. tremembensis, conocida por restos procedentes del Oligoceno (Formación Tremembé) de la localidad Padre Eterno, Brasil (Chiappe, 1988). Adicionalmente, numerosos hallazgos indican la existencia de los géneros actuales Melanosuchus y Caiman para el Mioceno Medio-Superior de diversas localidades de Venezuela, Brasil y Argentina (Langston, 1965; Langston & Gasparini, 1997; Gasparini, 1996; Brochu, 1999; Piña & Argañaraz, 2000 ), registrándose incluso especímenes que han sido referidos a las especies vivientes C. yacare y C. latirostris exhumados en el Mioceno de Argentina (Gasparini, 1981Gasparini, , 1996 ). ...
Se describen nuevos materiales fósiles de anfibios y reptiles hallados en sedimentos referidos a la Formación Cerro Azul (Mioceno Superior), procedentes de numerosas localidades de la provincia de La Pampa, Argentina. Los nuevos registros se basan en un resto craneano de anuro asignado al género Ceratophrys, restos de caparazón de tortugas terrestres del género Chelonoidis, vértebras asignables al lagarto de la familia Teiidae Tupinambis, y una vértebra troncal de serpiente comparable al género de colubroideos actuales Philodryas. Tanto los registros terciarios previos de géneros actuales de anfibios y reptiles en América del Sur, como así también la asociación recuperada en el Mioceno Superior de La Pampa sugieren que la mayoría de los géneros que componen la herpetofauna Neotropical estaban presentes en el Mioceno, patrón similar al observado en otras regiones del mundo.
Shape ontogenetic changes of the lower jaw in crocodylians are poorly understood. In order to answer some questions related to the inter- and intraspecific morphological variation of the mandible of two extant Caiman species, we performed a three-dimensional geometric morphometric approach. For this purpose, we used landmarks and semilandmarks on two ontogenetic mandibular series of 48 and 15 post-hatching specimens of C. yacare and C. latirostris , respectively. We have also examined the relationship between these anatomical transformations and ontogenetic shifts in diet. We performed a principal component analysis (PCA) for the two species, and regression and partial least squares (PLS) analyses for each species, separately. As a result, species were segregated along the PC1 with specimens of C. yacare showing more gracile mandibles, and specimens of C. latirostris more robust ones. The PC2 and regression analyses showed an age gradient and represented ontogenetic shape changes. Adult caiman mandibles are higher and wider than juvenile ones, and shape changes are more conspicuous in C. latirostris . The PLS analyses showed a significant relationship between shape and diet. Morphological changes of the PLS1 of block-1 match with those of the regression analysis for both species. We have detected morphological transformations in areas where the musculature in charge of mandibular movements is attached. Common morphological changes occurring during ontogeny seem to reflect the same mechanical properties required for crushing and killing in both species, driven by an ontogenetic shift in the diet from invertebrates to vertebrates. Additionally, interspecific differences were also found to be correlated to ontogenetic changes in diet and could be related to dissimilar feeding mechanical requirements ( e.g ., stiffness and toughness of the item consumed), and to different habitat preferences. Robust mandibles would be more suitable for shallow and fully vegetated environments, as it can be seen in C. latirostris , whereas slender jaws seem to be more suitable for more aquatic species such as C. yacare .
Alligatoroidea is the most species-rich crocodylomorph clade of the Cenozoic of South America, with nearly all species belonging to the Caimaninae clade. However, the earliest records of Caimaninae in South America, which are from the Palaeocene, are based mostly on incomplete specimens, which increases the importance of detailed taxonomic and phylogenetic studies on these taxa. This paper offers a taxonomic and phylogenetic review of Necrosuchus ionensis, a caimanine species from the Salamanca Formation of the Palaeocene of Argentina. Necrosuchus ionensis is considered a valid species, albeit with a different diagnosis from that proposed by previous authors. The phylogenetic analysis shows, for the first time, that N. ionensis belongs to the derived Caimaninae clade Jacarea. However, a better understanding of the Jacarea clade is needed, and alternative placements for N. ionensis might be considered. Nevertheless, the placement of N. ionensis as a derived caimanine raises interesting perspectives on the early evolution and radiation of caimanines, which are thoroughly discussed in this paper together with other results obtained in this study, such as the recovery of the North American caimanines Bottosaurus and Tsoabichi as a clade.
Laboratory experiments with Caiman crocodilus in a thermal gradient established that there is a significant difference between the mean preferred body temperatures of small (less than 45 cm total length) and large (more than 75 cm total length) individuals. The levels of thermal preference were irrespective of sex and feeding (digestive) state. When out of water Caiman crocodilus thermoregulates behaviorally similar to heliothermic lizards. The effects of mouth gaping and gular fluttering were assessed as physiologically insignificant as cooling mechanism in critically overheated Caiman crocodilus and Crocodylus niloticus. Mouth gaping did not play a role in cooling the brain, in Caiman crocodilus. Caiman crocodilus resorted to moving into water when overheated, and this behavior had a measurable effect on heat loss, even when large animals stayed in water for as short as 10 sec.
A new sebecid from the early Eocene of Jujuy, with more generalized characteristics than Sebecus, is described. A tooth from the same formation (Lumbrera Formation, Salta Group) and age, in the province of Salta, is assigned to ?Sebecus sp. Another sebecosuchian comes from the late Eocene of Mendoza. A sebecid from the early Oligocene in Patagonia (Chubut) is the most recent record of sebecosuchians in Argentina. Certain local environments in the Tertiary of South America are inferred on the basis of presence of sebecosuchians and associated herpetofauna. Hypotheses of origin and geographical distribution of the Sebecosuchia s.l. (Langston, 1956; Sill, 1969; Steel, 1973; Buffetaut, 1980; Molnar, 1981) are analyzed. Finally, it is confirmed that ziphodonty arose several times during crocodilian history, and that in order to understand the origin and evolution of the Sebecosuchia it will be necessary to have more and better material.
New Crocodjlians from the Upper Paleocene of Western Colorado. Field Mus
- K P Schmidt
SCHMIDT, K.P. 1938. New Crocodjlians from the Upper Paleocene of Western Colorado.
Field Mus. Nat. Hi st., Geol. Series, 6: 31 5-21.
Mammals and Stratigraphy: Geochronology of the Continental Mammal -bearing
- L G Marshall
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- R Pascual
MARSHALL, L.G.; HOFFSTETTER, R.; PASCUAL, R. 1983. Mammals and Stratigraphy:
Geochronology of the Continental Mammal -bearing. Tertiary of South America. Paleeomertebreta, Montpellier, MBrn. Extr.: 1-93.
Les Crocodiliens de !'Eocene infgrieur de Dormaal (Brabant, Belgique)
- E Buffet'aut
BUFFET'AUT, E. 1985. Les Crocodiliens de !'Eocene infgrieur de Dormaal (Brabant, Belgique). Bull. Soc. belge Geol., Bruxelles, 94(1): 51 -9.