RESUMO
The endocranial structures of the sebecid crocodylomorph Zulmasuchus querejazus (MHNC 6672) from the Lower Paleocene of Bolivia are described in this article. Using computed tomography scanning, the cranial endocast, associated nerves and arteries, endosseous labyrinths, and cranial pneumatization are reconstructed and compared with those of extant and fossil crocodylomorphs, representative of different ecomorphological adaptations. Z. querejazus exhibits an unusual flexure of the brain, pericerebral spines, semicircular canals with a narrow diameter, as well as enlarged pharyngotympanic sinuses. First, those structures allow to estimate the alert head posture and hearing capabilities of Zulmasuchus. Then, functional comparisons are proposed between this purportedly terrestrial taxon, semi-aquatic, and aquatic forms (extant crocodylians, thalattosuchians, and dyrosaurids). The narrow diameter of the semicircular canals but expanded morphology of the endosseous labyrinths and the enlarged pneumatization of the skull compared to other forms indeed tend to indicate a terrestrial lifestyle for Zulmasuchus. Our results highlight the need to gather new data, especially from altirostral forms in order to further our understanding of the evolution of endocranial structures in crocodylomorphs with different ecomorphological adaptations.
Assuntos
Evolução Biológica , Dinossauros/anatomia & histologia , Fósseis/anatomia & histologia , Canais Semicirculares/anatomia & histologia , Crânio/diagnóstico por imagem , Animais , Artérias/anatomia & histologia , Artérias/diagnóstico por imagem , Bolívia , Encéfalo/anatomia & histologia , Encéfalo/diagnóstico por imagem , Vértebras Cervicais/anatomia & histologia , Vértebras Cervicais/diagnóstico por imagem , Nervos Cranianos/anatomia & histologia , Nervos Cranianos/diagnóstico por imagem , Cavidades Cranianas/anatomia & histologia , Cavidades Cranianas/diagnóstico por imagem , Dinossauros/fisiologia , Orelha Interna/anatomia & histologia , Orelha Interna/diagnóstico por imagem , Fósseis/diagnóstico por imagem , Audição , Estilo de Vida , Postura , Canais Semicirculares/diagnóstico por imagem , Crânio/anatomia & histologia , Crânio/irrigação sanguínea , Tomógrafos ComputadorizadosRESUMO
At the end of the Cretaceous Period, an asteroid collided with the Earth and formed the Chicxulub impact structure on the Yucatán Platform. International Ocean Discovery Program (IODP) Expedition 364 drilled into the peak ring of the Chicxulub impact crater. The post-impact section of the core was sampled for terrestrial palynological analysis, yielding a high-resolution record ranging from the early Paleocene to the earliest Eocene (Ypresian), including a black shale deposited during the Paleocene-Eocene Thermal Maximum (PETM). The IODP 364 core provides the first record of floral recovery following the K-Pg mass extinction from inside the Chicxulub impact crater. The systematic taxonomy of the angiosperm pollen provided here follows a separate publication describing the systematic paleontology of the plant spores and gymnosperm pollen from the IODP 364 core (Smith et al. 2019). The Paleocene section of the core is nearly barren, but with unusually high relative abundances of the angiosperm pollen Chenopodipollis sp. A (comparable to the Amaranthaceae), possibly indicating an estuarine pollen source. Pollen recovery is higher in the PETM section, and variable but generally increasing in the later Ypresian section, with excellent preservation in several samples. Estimated absolute ages of several potentially useful regional biostratigraphic events are provided. One new genus (Scabrastephanoporites) and five new species (Brosipollis reticulatus, Echimonocolpites chicxulubensis, Psilastephanocolporites hammenii, Scabrastephanoporites variabilis, and Striatopollis grahamii) are formally described.
RESUMO
This contribution describes the skull remains of a swordfish (Perciformes, Xiphioidei), recovered from Middle Eocene beds of central Chile. Comparison with known fossil and extant xiphioids reveals derived traits only present in the Neogene swordfish Xiphias gladius (Xiphiidae, Xiphiinae), these being a elongated rostrum composed of premaxillaries and possible prenasals, a dorsoventrally high and slender hyomandibular-metapterygoid complex, and a rounded, convex operculum. Also, strong ridges and sulci are present in the dorsal part of the rostrum, a feature only present in the billfish genera Aglyptorhynchus and Xiphiorhynchus, and in the swordfish genus Blochius. In addition, the specimen also has villiform teeth in the rostrum and lower jaw, a feature previously documented only in the Paleocene genus Hemingwaya. Such a unique combination of characters in the specimen allows classifying it as a new genus and species, Loancorhynchus catrillancai. Phylogenetic analyses obtained Xiphiorhynchus outside the Xiphiidae, suggesting instead narrow relationships to the Paleocene-Eocene genera Hemingwaya + Palaeorhynchus + Homorhynchus. Loancorhynchus is obtained as an intermediate form between Xiphias and Blochius. The specimen represents the first Paleogene swordfish described in the southeastern Pacific.
RESUMO
PREMISE OF THE STUDY: The fossil record of Agathis historically has been restricted to Australasia. Recently described fossils from the Eocene of Patagonian Argentina showed a broader distribution than found previously, which is reinforced here with a new early Paleocene Agathis species from Patagonia. No previous phylogenetic analyses have included fossil Agathis species. METHODS: We describe macrofossils from Patagonia of Agathis vegetative and reproductive organs from the early Danian, as well as leaves with Agathis affinities from the latest Maastrichtian. A total evidence phylogenetic analysis is performed, including the new Danian species together with other fossil species having agathioid affinities. KEY RESULTS: Early Danian Agathis immortalis sp. nov. is the oldest definite occurrence of Agathis and one of the most complete Agathis species in the fossil record. Leafy twigs, leaves, pollen cones, pollen, ovuliferous complexes, and seeds show features that are extremely similar to the living genus. Dilwynites pollen grains, associated today with both Wollemia and Agathis and known since the Turonian, were found in situ within the pollen cones. CONCLUSIONS: Agathis was present in Patagonia ca. 2 million years after the K-Pg boundary, and the putative latest Cretaceous fossils suggest that the genus survived the K-Pg extinction. Agathis immortalis sp nov. is recovered in a stem position for the genus, while A. zamunerae (Eocene, Patagonia) is recovered as part of the crown. A Mesozoic divergence for the Araucariaceae crown group, previously challenged by molecular divergence estimates, is supported by the combined phylogenetic analyses including the fossil taxa.
Assuntos
Evolução Biológica , Fósseis/ultraestrutura , Traqueófitas/genética , Argentina , Traqueófitas/ultraestruturaRESUMO
PREMISE OF THE STUDY: The fossil record is critical for testing biogeographic hypotheses. Menispermaceae (moonseeds) are a widespread family with a rich fossil record and alternative hypotheses related to their origin and diversification. The family is well-represented in Cenozoic deposits of the northern hemisphere, but the record in the southern hemisphere is sparse. Filling in the southern record of moonseeds will improve our ability to evaluate alternative biogeographic hypotheses. METHODS: Fossils were collected from the Salamanca (early Paleocene, Danian) and the Huitrera (early Eocene, Ypresian) formations in Chubut Province, Argentina. We photographed them using light microscopy, epifluorescence, and scanning electron microscopy and compared the fossils with similar extant and fossil Menispermaceae using herbarium specimens and published literature. KEY RESULTS: We describe fossil leaves and endocarps attributed to Menispermaceae from Argentinean Patagonia. The leaves are identified to the family, and the endocarps are further identified to the tribe Cissampelideae. The Salamancan endocarp is assigned to the extant genus Stephania. These fossils significantly expand the known range of Menispermaceae in South America, and they include the oldest (ca. 64 Ma) unequivocal evidence of the family worldwide. CONCLUSIONS: Our findings highlight the importance of West Gondwana in the evolution of Menispermaceae during the Paleogene. Currently, the fossil record does not discern between a Laurasian or Gondwanan origin; however, it does demonstrate that Menispermaceae grew well outside the tropics by the early Paleocene. The endocarps' affinity with Cissampelideae suggests that diversification of the family was well underway by the earliest Paleocene.
Assuntos
Fósseis/anatomia & histologia , Menispermaceae/anatomia & histologia , Menispermaceae/classificação , Argentina , Fósseis/ultraestrutura , Frutas/anatomia & histologia , Frutas/classificação , Frutas/ultraestrutura , Menispermaceae/ultraestrutura , Microscopia Eletrônica de Varredura , Dispersão Vegetal , Folhas de Planta/anatomia & histologia , Folhas de Planta/classificação , Folhas de Planta/ultraestruturaRESUMO
ABSTRACT Paleocene ostracods and planktonic foraminifera from the Maria Farinha Formation, Paraíba Basin, are herein presented. Eleven ostracod species were identified in the genera Cytherella Jones, Cytherelloidea Alexander, Eocytheropteron Alexander, Semicytherura Wagner, Paracosta Siddiqui, Buntonia Howe, Soudanella Apostolescu, Leguminocythereis Howe and, probably, Pataviella Liebau. The planktonic foraminifera are represented by the genera Guembelitria Cushman, Parvularugoglobigerina Hofker, Woodringina Loeblich and Tappan, Heterohelix Ehrenberg, Zeauvigerina Finlay, Muricohedbergella Huber and Leckie, and Praemurica Olsson, Hemleben, Berggren and Liu. The ostracods and foraminifera analyzed indicate an inner shelf paleoenvironment for the studied section. Blooms of Guembelitria spp., which indicate either shallow environments or upwelling zones, were also recorded reinforcing previous paleoenvironmental interpretations based on other fossil groups for this basin.
Assuntos
Animais , Crustáceos/classificação , Foraminíferos/classificação , Brasil , Microscopia Eletrônica de Varredura , Crustáceos/ultraestrutura , Foraminíferos/ultraestrutura , Fósseis/ultraestruturaRESUMO
Based on a single male specimen, a remarkable new species of the genus Navicordulia is described from the Massif du Mitaraka in French Guiana (Tumuc-Humac Mountains). Another new species of this genus is also reported from the same locality but is not described. This is the first record of the genus from French Guiana, hitherto being unknown within a radius of more than 1000 km. Apparent rarity or absence of records is probably due to its secretive habits. Navicordulia tumucurakensis sp. nov. presents unique characters not present in other species of the genus including: almost no excavation of the anal angle, proximal sternal pilose ridge of abdominal segment 7 transformed into two large lateral oreillets disconnected from the median carina, additional distal sternal pilose ridge transformed into a medial knob, epiproct not extending beyond the distal half of the cerci, very long cerci surpassing those of described species, cerci lacking ventro-medial carina and tubercle and exhibiting a distal ventral brush of hair-like setae. It is a forest species inhabiting hilly landscapes at low altitude, unlike other closely related intertropical species which are encountered in more elevated areas above 850 m. It is most closely related to N. longistyla, a typical cerrado species from the central Brazilian plateau or possibly to N. nitens from the central south Venezuelan Guaiquinima Tepui. Based on unique derived male abdominal structures and also on the female ovipositor and related structures, the South American genus Navicordulia and the Southeast Asian/Melanesian genus Metaphya are considered current adelphotaxa. This disrupted geographic distribution could be explained by a common ancestor having had a Gondwanian dispersal until the Late Cretaceous or Paleocene.
Assuntos
Odonatos , Animais , Brasil , Feminino , Florestas , Guiana Francesa , Masculino , FilogeniaRESUMO
The limestones of Itaboraí Basin (Middle Paleocene), Rio de Janeiro, Brazil, harbor a rich fossil molluscan fauna consisting exclusively of pulmonate snails, both terrestrial and freshwater. An extensive taxonomic revision of this paleofauna is conducted here. A new genus, Cortana, is described as well as two new species, Eoborus fusiforme and Gastrocopta itaboraiensis. The revised classification is as follows: Austrodiscus lopesi (Charopidae); Biomphalaria itaboraiensis (Planorbidae); "Brachypodella" britoi (Urocoptidae); Brasilennea arethusae, Brasilennea guttula, Brasilennea minor (Cerionidae); Bulimulus fazendicus, Bulimulus trindadeae, Cortana carvalhoi, Cyclodontina coelhoi, Itaborahia lamegoi, Leiostracus ferreirai, Plagiodontes aff. dentatus (Orthalicidae); Cecilioides sommeri (Ferussaciidae); Eoborus rotundus, Eoborus sanctijosephi, Eoborus fusiforme (Strophocheilidae); Gastrocopta mezzalirai, Gastrocopta itaboraiensis (Gastrocoptidae); Temesa magalhaesi (Clausiliidae). The species Strobilopsis mauryae was considered a synonym of Brasilennea arethusae; Bulimulus sommeri a synonym of Itaborahia lamegoi; and Vorticifex fluminensis a synonym of Eoborus sanctijosephi. Itaboraí Basin has the most ancient records of the families Orthalicidae, Gastrocoptidae, Ferussaciidae and Strophocheilidae. Moreover, the basin's records of Charopidae, Clausiliidae, Cerionidae, and Urocoptidae are among the most ancient in the world and, among these, those of Cerionidae, Clausiliidae and Urocoptidae deserve special attention since they are greatly removed from these families' current distribution. Additionally, Itaboraí has the most ancient records for the genera Austrodiscus, Brachypodella, Bulimulus, Cecilioides, Cyclodontina, Eoborus, Gastrocopta, Leiostracus, Plagiodontes and Temesa. There are three endemic genera in the basin: Brasilennea, Cortana and Itaborahia. Further discussion on paleobiogeography and evolution of this paleofauna is also provided.
Os calcários da Bacia de Itaboraí (Paleoceno Médio), Rio de Janeiro, Brasil, abrigam uma rica fauna de gastrópodes pulmonados do Paleoceno Médio, tanto terrestres quanto dulciaquícolas. No presente trabalho realiza-se uma extensiva revisão taxonômica dessa paleofauna. Duas novas espécies, Eoborus fusiforme e Gastrocopta itaboraiensis, são descritas, assim como um novo gênero, Cortana. A classificação revisada encontra-se do seguinte modo: Austrodiscus lopesi (Charopidae); Biomphalaria itaboraiensis (Planorbidae); "Brachypodella" britoi (Urocoptidae); Brasilennea arethusae, Brasilennea guttula, Brasilennea minor (Cerionidae); Bulimulus fazendicus, Bulimulus trindadeae, Cortana carvalhoi, Cyclodontina coelhoi, Itaborahia lamegoi, Leiostracus ferreirai, Plagiodontes aff. dentatus (Orthalicidae); Cecilioides sommeri (Ferussaciidae); Eoborus rotundus, Eoborus sanctijosephi, Eoborus fusiforme (Strophocheilidae); Gastrocopta mezzalirai, Gastrocopta itaboraiensis (Gastrocoptidae); Temesa magalhaesi (Clausiliidae). A espécie Strobilopsis mauryae foi considerada sinônimo de Brasilennea arethusae; Bulimulus sommeri sinônimo de Itaborahia lamegoi; e Vorticifex fluminensis sinônimo de Eoborus sanctijosephi. A bacia conta com os registros fósseis mais antigos das famílias Orthalicidae, Gastrocoptidae, Ferussaciidae e Strophocheilidae. Além disso, os registros de Itaboraí das famílias Charopidae, Clausiliidae, Cerionidae, e Urocoptidae estão entre os mais antigos do mundo e, dentre esses, os de Cerionidae, Clausiliidae e Urocoptidae merecem destaque por estarem bem afastados das distribuições atuais das famílias. Ademais, os registros de Itaboraí são os mais antigos para os gêneros Austrodiscus, Brachypodella, Bulimulus, Cecilioides, Cyclodontina, Eoborus, Gastrocopta, Leiostracus, Plagiodontes e Temesa. Há três gêneros endêmicos na bacia: Brasilennea, Cortana e Itaborahia. Discussões adicionais sobre paleobiogeografia e evolução dessa paleofauna são oferecidas.
Assuntos
Animais , Fauna/análise , Gastrópodes/anatomia & histologia , ClassificaçãoRESUMO
The limestones of Itaboraí Basin (Middle Paleocene), Rio de Janeiro, Brazil, harbor a rich fossil molluscan fauna consisting exclusively of pulmonate snails, both terrestrial and freshwater. An extensive taxonomic revision of this paleofauna is conducted here. A new genus, Cortana, is described as well as two new species, Eoborus fusiforme and Gastrocopta itaboraiensis. The revised classification is as follows: Austrodiscus lopesi (Charopidae); Biomphalaria itaboraiensis (Planorbidae); "Brachypodella" britoi (Urocoptidae); Brasilennea arethusae, Brasilennea guttula, Brasilennea minor (Cerionidae); Bulimulus fazendicus, Bulimulus trindadeae, Cortana carvalhoi, Cyclodontina coelhoi, Itaborahia lamegoi, Leiostracus ferreirai, Plagiodontes aff. dentatus (Orthalicidae); Cecilioides sommeri (Ferussaciidae); Eoborus rotundus, Eoborus sanctijosephi, Eoborus fusiforme (Strophocheilidae); Gastrocopta mezzalirai, Gastrocopta itaboraiensis (Gastrocoptidae); Temesa magalhaesi (Clausiliidae). The species Strobilopsis mauryae was considered a synonym of Brasilennea arethusae; Bulimulus sommeri a synonym of Itaborahia lamegoi; and Vorticifex fluminensis a synonym of Eoborus sanctijosephi. Itaboraí Basin has the most ancient records of the families Orthalicidae, Gastrocoptidae, Ferussaciidae and Strophocheilidae. Moreover, the basin's records of Charopidae, Clausiliidae, Cerionidae, and Urocoptidae are among the most ancient in the world and, among these, those of Cerionidae, Clausiliidae and Urocoptidae deserve special attention since they are greatly removed from these families' current distribution. Additionally, Itaboraí has the most ancient records for the genera Austrodiscus, Brachypodella, Bulimulus, Cecilioides, Cyclodontina, Eoborus, Gastrocopta, Leiostracus, Plagiodontes and Temesa. There are three endemic genera in the basin: Brasilennea, Cortana and Itaborahia. Further discussion on paleobiogeography and evolution of this paleofauna is also provided.(AU)
Os calcários da Bacia de Itaboraí (Paleoceno Médio), Rio de Janeiro, Brasil, abrigam uma rica fauna de gastrópodes pulmonados do Paleoceno Médio, tanto terrestres quanto dulciaquícolas. No presente trabalho realiza-se uma extensiva revisão taxonômica dessa paleofauna. Duas novas espécies, Eoborus fusiforme e Gastrocopta itaboraiensis, são descritas, assim como um novo gênero, Cortana. A classificação revisada encontra-se do seguinte modo: Austrodiscus lopesi (Charopidae); Biomphalaria itaboraiensis (Planorbidae); "Brachypodella" britoi (Urocoptidae); Brasilennea arethusae, Brasilennea guttula, Brasilennea minor (Cerionidae); Bulimulus fazendicus, Bulimulus trindadeae, Cortana carvalhoi, Cyclodontina coelhoi, Itaborahia lamegoi, Leiostracus ferreirai, Plagiodontes aff. dentatus (Orthalicidae); Cecilioides sommeri (Ferussaciidae); Eoborus rotundus, Eoborus sanctijosephi, Eoborus fusiforme (Strophocheilidae); Gastrocopta mezzalirai, Gastrocopta itaboraiensis (Gastrocoptidae); Temesa magalhaesi (Clausiliidae). A espécie Strobilopsis mauryae foi considerada sinônimo de Brasilennea arethusae; Bulimulus sommeri sinônimo de Itaborahia lamegoi; e Vorticifex fluminensis sinônimo de Eoborus sanctijosephi. A bacia conta com os registros fósseis mais antigos das famílias Orthalicidae, Gastrocoptidae, Ferussaciidae e Strophocheilidae. Além disso, os registros de Itaboraí das famílias Charopidae, Clausiliidae, Cerionidae, e Urocoptidae estão entre os mais antigos do mundo e, dentre esses, os de Cerionidae, Clausiliidae e Urocoptidae merecem destaque por estarem bem afastados das distribuições atuais das famílias. Ademais, os registros de Itaboraí são os mais antigos para os gêneros Austrodiscus, Brachypodella, Bulimulus, Cecilioides, Cyclodontina, Eoborus, Gastrocopta, Leiostracus, Plagiodontes e Temesa. Há três gêneros endêmicos na bacia: Brasilennea, Cortana e Itaborahia. Discussões adicionais sobre paleobiogeografia e evolução dessa paleofauna são oferecidas.(AU)