A reassessment of bunodont metatherians from the paleogene of itaboraí (Brazil): systematics and age of the Itaboraian salma

Early Paleogene metatherians with inflated, low cusps (bunodont dentition), such as Bobbschaefferia, Procaroloameghinia, Protodidelphis, Guggenheimia, and Zeusdelphys have been subject to different interpretations regarding their affinities. A phylogenetic study including these bunodont marsupials and other selected metatherians presented here leads to the recognition of the following taxonomic assignments: "Ameridelphia", Protodidelphidae: Carolocoutoia ferigoloi, Guggenheimia brasiliensis, G. crocheti sp. nov., Protodidelphis vanzolinii, P. mastodontoides (=Robertbutleria mastodontoidea), Periprotodidelphis bergqvisti gen. et sp. nov., and Zeusdelphys complicatus; Marsupialia, Didelphimorphia, Peradectoidea, Caroloameghiniidae: Procaroloameghinia pricei; Australidelphia, Polydolopimorphia, family indet.: Bobbschaefferia fluminensis and aff. Bobbschaefferia sp. The phylogenetic analysis does not support a closer relationship between protodidelphids and living didelphids as well as between Guggenheimia and Mirandatherium. No closer relationship was found between Zeusdelphys with Minusculodelphis and Monodelphopsis. Procaroloameghinia is regarded as a peradectoid didelphimorphian with bunoid dentition convergent with, but without direct affinities to, protodidelphids or polydolopimorphians. Bobbschaefferia is regarded as a basal polydolopimorphian, even though the scarce evidence at hand prevents us from assign it to any particular family of the suborder Hatcheriformes. Correlation with stratigraphic, sedimentary and magmatic data from some of the best studied margin basins in SE Brazil, together with the systematic reassessment of bunodont metatherians from Itaboraí, suggest that the Itaboraian SALMA is latest Paleoceneearly Eocene in age. Itaboraian protodidelphids, sternbergiids and caroloameghiniids are also recorded in the Las Flores locality/ Formation (central Patagonia) and in the La Barda locality (northwestern Patagonia) during the latest Paleocene and early Eocene.Metatérios do Paleógeno inicial com cúspides infladas e baixas (bunodontes) como Bobbschaefferia, Procaroloameghinia, Protodidelphis, Guggenheimia e Zeusdelphys têm sido objeto de diferentes interpretações sobre suas afinidades. Um estudo filogenético, incluindo esses marsupiais bunodontes, assim como outros metatérios selecionados, conduz ao reconhecimento das seguintes atribuições taxonômicas: “Ameridelphia”, Protodidelphidae: Carolocoutoia ferigoloi, Guggenheimia brasiliensis, G. crocheti sp. nov., Protodidelphis vanzolinii, P. mastodontoides (= Robertbutleria mastodontoidea), Periprotodidelphis bergqvisti gen. et sp. nov. e Zeusdelphys complicatus; Marsupialia, Didelphimorphia, Peradectoidea, Caroloameghiniidae: Procaroloameghinia pricei; Australidelphia, Polydolopimorphia, fam. indet.: Bobbschaefferia fluminensis and aff. Bobbschaefferia sp.. A análise filogenética não fornece suporte a uma íntima relação entre protodidelfídeos e didelfídeos viventes. Nenhuma relação próxima foi encontrada entre Zeusdelphys com Minusculodelphis e Monodelphopsis. Procaroloameghinia é posicionado como um didelfimórfio basal (Peradectoidea, Caroloameghiniidae), com dentição bunodonte convergente, porém sem afinidade direta a protodidelfídeos e polidolopimórfios. Bobbschaefferia é considerado como um polidolopimórfio basal, embora sua escassa evidência impossibilite atribuí-lo a qualquer família em particular da subordem Hatcheriformes. Correlação com dados estratigráficos, sedimentares e magmáticos de algumas bacias marginais bem estudadas do sudeste do Brasil, juntamente com a revisão sistemática de metatérios bunodontes de Itaboraí, sugere que a SALMA Itaboraiense é de idade Paleoceno tardioEoceno inicial. Protodidelfídeos, sternbergídeos e caroloameghinídeos itaboraienses são também reportados na localidade/Formação Las Flores (Patagonia central) e na localidade La Barda (NE Patagonia) durante o Paleoceno tardio e o Eoceno inicial.Facultad de Ciencias Naturales y Muse

A new species of Gaylordia Paula Couto (Mammalia, Metatheria) from Itaboraí, Brazil

We describe a new metatherian of the genus Gaylordia Paula Couto, from the early Eocene Itaboraí Basin, Brazil. This new species (estimated body mass ~60-90.9 g) is based on lower and upper dentition elements and is characterized by a more plesiomorphic dental morphology with respect to G. macrocynodonta Paula Couto (with a larger body mass, estimated in ~74-103 g for large individuals or males). The species G. doelloi Marshall, represented by small individuals or females, is regarded a junior synonym of G. macrocynodonta. A phylogenetic analysis as well as details of the occlusal surface of its upper and lower molars suggests that Gaylordia is closely related to the Pucadelphyidae, a non-marsupial “ameridelphian” group previously recorded at the early Paleocene locality of Tiupampa, Bolivia.Descreve-se um novo marsupial basal do gênero Gaylordia Paula Couto, do Eoceno inicial da bacia de Itaboraí, Brasil. Esta nova espécie (massa corporal estimada ~60-90.9 g) está baseada na dentição superior e inferior, e é caracterizada por uma morfologia dentária mais plesiomórfi ca em relação a G. macrocynodonta Paula Couto (cuja maior massa corporal é estimada em ~74-103 g para grandes indivíduos ou machos). A espécie G. doelloi Marshall, representada por indíviduos pequenos ou fêmeas, é considerada um sinônimo junior de G. macrocynodonta. Uma análise fi logenética, bem como detalhes da superfície oclusal de seus molares superiores e inferiores sugerem uma relação próxima de Gaylordia aos Pucadelphyidae, um grupo de ameridélfi os não marsupiais previamente registrados no Paleoceno inicial da localidade de Tiupampa, Bolivia.Facultad de Ciencias Naturales y Muse

El enfriamiento global del Oligoceno temprano y la segunda radiación de los Metatheria en América del Sur

Así como el calentamiento global de comienzos del Cretácico Superior parece haber implicado la primera gran radiación de los Metatheria, el fin de este ciclo de "mundo invernadero", hacia el límite Eoceno-Oligoceno, implicó una segunda y radical transformación de este grupo de mamíferos. En el Hemisferio Sur, la mejor secuencia biocronológica registrada en la parte austral de América del Sur permite apreciar esta última fase de cambios con cierta precisión. En contribuciones previas hemos enmarcado estos procesos como el fin de la Fase Sudamericana Temprana y el comienzo de la Fase Sudamericana Tardía en la evolución de nuestros mamíferos, denominando "Bisagra Patagónica" al evento de recambios faunísticos producido como consecuencia del enfriamiento global del Oligoceno más temprano. El cambio de escenarios evolutivos que trajo aparejado el comienzo del "mundo frigorífico" puede apreciarse en dos aspectos fundamentales del recambio sufrido por los Metatheria sudamericanos australes: taxonómico y adaptativo. Los hitos del recambio taxonómico (no influido por el -posterior- arribo de roedores y primates inmigrantes) son los siguientes: 1) último registro de los Peradectoidea y de otros linajes de "comadrejas" ("Didelphimorphia") característicos del Paleoceno - Eoceno; 2) entre los Microbiotheria, el recambio entre los Woodburnodontidae (Paleoceno-Eoceno tardío) y los Microbiotheriidae (Eoceno tardío - reciente); 3) entre los Polydolopimorphia, la extinción de los Polydolopiformes y de los Bonapartheriiformes Bonapartherioidea, y la radiación de los Bonapartheriiformes Argyrolagoidea; 4) rápida diversificación de los Paucituberculata. Entre los cambios adaptativos pueden señalarse: 5) procesos de gigantismo en varios linajes (Polydolopidae, Borhyaenidae); 6) adaptaciones hacia la granivoría o la ingesta de frutos duros en los Polydolopidae; 7) finalmente, una marcada declinación de los tipos frugívoros y el desarrollo, en grupos muy diversos, de crestas en las series molares. Hacia la Edad-mamífero Colhuehuapense (Mioceno temprano), el producto de este marcado recambio entre los Metatheria ya se había establecido plenamente.Simposio V: Los mamíferos oligocenos de América del Sur: explosión evolutiva de los mamíferos nativos y llegada de los emigrantes africanosFacultad de Ciencias Naturales y Muse

Los bustos del Museo de La Plata

El visitante atento a la fachada del Museo de La Plata no dejará de advertir, a ambos lados de la misma, dos series de seis bustos o retratos escultóricos de distinguidos naturalistas. Para Luciano Passarella estas representaciones constituyen un “programa iconográfico sincrético”, destinado a transmitir la cosmovisión de la Generación del ’80 al público visitante.Fundación Museo de La Plat

A reassessment of bunodont metatherians from the paleogene of itaboraí (Brazil): systematics and age of the Itaboraian salma

Early Paleogene metatherians with inflated, low cusps (bunodont dentition), such as Bobbschaefferia, Procaroloameghinia, Protodidelphis, Guggenheimia, and Zeusdelphys have been subject to different interpretations regarding their affinities. A phylogenetic study including these bunodont marsupials and other selected metatherians presented here leads to the recognition of the following taxonomic assignments: "Ameridelphia", Protodidelphidae: Carolocoutoia ferigoloi, Guggenheimia brasiliensis, G. crocheti sp. nov., Protodidelphis vanzolinii, P. mastodontoides (=Robertbutleria mastodontoidea), Periprotodidelphis bergqvisti gen. et sp. nov., and Zeusdelphys complicatus; Marsupialia, Didelphimorphia, Peradectoidea, Caroloameghiniidae: Procaroloameghinia pricei; Australidelphia, Polydolopimorphia, family indet.: Bobbschaefferia fluminensis and aff. Bobbschaefferia sp. The phylogenetic analysis does not support a closer relationship between protodidelphids and living didelphids as well as between Guggenheimia and Mirandatherium. No closer relationship was found between Zeusdelphys with Minusculodelphis and Monodelphopsis. Procaroloameghinia is regarded as a peradectoid didelphimorphian with bunoid dentition convergent with, but without direct affinities to, protodidelphids or polydolopimorphians. Bobbschaefferia is regarded as a basal polydolopimorphian, even though the scarce evidence at hand prevents us from assign it to any particular family of the suborder Hatcheriformes. Correlation with stratigraphic, sedimentary and magmatic data from some of the best studied margin basins in SE Brazil, together with the systematic reassessment of bunodont metatherians from Itaboraí, suggest that the Itaboraian SALMA is latest Paleoceneearly Eocene in age. Itaboraian protodidelphids, sternbergiids and caroloameghiniids are also recorded in the Las Flores locality/ Formation (central Patagonia) and in the La Barda locality (northwestern Patagonia) during the latest Paleocene and early Eocene.Metatérios do Paleógeno inicial com cúspides infladas e baixas (bunodontes) como Bobbschaefferia, Procaroloameghinia, Protodidelphis, Guggenheimia e Zeusdelphys têm sido objeto de diferentes interpretações sobre suas afinidades. Um estudo filogenético, incluindo esses marsupiais bunodontes, assim como outros metatérios selecionados, conduz ao reconhecimento das seguintes atribuições taxonômicas: “Ameridelphia”, Protodidelphidae: Carolocoutoia ferigoloi, Guggenheimia brasiliensis, G. crocheti sp. nov., Protodidelphis vanzolinii, P. mastodontoides (= Robertbutleria mastodontoidea), Periprotodidelphis bergqvisti gen. et sp. nov. e Zeusdelphys complicatus; Marsupialia, Didelphimorphia, Peradectoidea, Caroloameghiniidae: Procaroloameghinia pricei; Australidelphia, Polydolopimorphia, fam. indet.: Bobbschaefferia fluminensis and aff. Bobbschaefferia sp.. A análise filogenética não fornece suporte a uma íntima relação entre protodidelfídeos e didelfídeos viventes. Nenhuma relação próxima foi encontrada entre Zeusdelphys com Minusculodelphis e Monodelphopsis. Procaroloameghinia é posicionado como um didelfimórfio basal (Peradectoidea, Caroloameghiniidae), com dentição bunodonte convergente, porém sem afinidade direta a protodidelfídeos e polidolopimórfios. Bobbschaefferia é considerado como um polidolopimórfio basal, embora sua escassa evidência impossibilite atribuí-lo a qualquer família em particular da subordem Hatcheriformes. Correlação com dados estratigráficos, sedimentares e magmáticos de algumas bacias marginais bem estudadas do sudeste do Brasil, juntamente com a revisão sistemática de metatérios bunodontes de Itaboraí, sugere que a SALMA Itaboraiense é de idade Paleoceno tardioEoceno inicial. Protodidelfídeos, sternbergídeos e caroloameghinídeos itaboraienses são também reportados na localidade/Formação Las Flores (Patagonia central) e na localidade La Barda (NE Patagonia) durante o Paleoceno tardio e o Eoceno inicial.Facultad de Ciencias Naturales y Muse

Los bustos del Museo de La Plata

El visitante atento a la fachada del Museo de La Plata no dejará de advertir, a ambos lados de la misma, dos series de seis bustos o retratos escultóricos de distinguidos naturalistas. Para Luciano Passarella estas representaciones constituyen un “programa iconográfico sincrético”, destinado a transmitir la cosmovisión de la Generación del ’80 al público visitante.Fundación Museo de La Plat

Contribution to the knowledge of living representatives of the genus Lutreolina Thomas, 1910 (Mammalia, Marsupialia, Didelphidae)

Se describe una nueva especie extinta del género Lutreolina Thomas, 1910 (Didelphidae, Didelphini). Lutreolina materdei sp. nov., del Mioceno tardío (Edad Huayqueriense) de la Amazonia peruana, se diferencia de las otras especies del género por su mayor tamaño y la presencia de molares inferiores con la paracrístida y la entocrístida más desarrolladas, la cresta posterolingual al metacónido (post-metacrístida) más grande, el hipoconúlido más reducido, la postprotocrístida formando un plano oblicuo con el talónido y el cíngulo anterobasal más estrecho. Asimismo, se describen un resto de basicráneo y un fragmento de dentario, referibles a Lutreolina sp., procedentes de niveles del Pleistoceno temprano del sudeste bonaerense. Los restos pertenecen a una forma robusta, posiblemente representativa de una nueva especie, si bien la imposibilidad de confrontarlos con los de otras especies del género impide el establecimiento de una nueva entidad específica.We describe a new species of the genus Lutreolina Thomas, 1910 (Didelphidae, Didelphini). Lutreolina materdei sp. nov., from the late Miocene (Huayquerian Age) of the Peruvian Amazonia differs from other species of the genus because of its larger size and lower molars with larger paracristid and entocristid; a conspicuous ridge posterolingual to the metaconid (post-metacristid); reduced hypoconulid, and posterior wall of the trigonid descending obliquely towards the talonid. We also describe new remains of Lutreolina sp. from Pleistocene levels of southeastern Buenos Aires Province. Both specimens are referable to a robust, possibly new species of the genus. However, the lack of highly diagnostic remains prevents its specific assignation.Fil: Goin, Francisco Javier. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Paleontología Vertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: de Los Reyes, Leonardo Martín. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; Argentin

Non-tribosphenic Gondwanan mammals and the alternative development of molars with a reversed triangle cusp pattern

Several lineages of non-holotherian Gondwanan mammals developed complex, tribosphenic-like molars, but not tribosphenic occlusion. The reversed triangle occlusal pattern, characteristic of holotherian lineages leading to tribosphenic occlusion, could have been acquired without a cusp rotation process. A review of the molar structure in primitive monotreme prototherians and gondwanathere allotherians suggests that a tricuspid pattern could have been accomplished by expansion of cingula, elevation of their cusps, and connection by ridges of two of the latter to one of the original ones, leading to a triangular pattern in some, or all, their molars. This cusp and ridge arrangement is already outlined in the lower cheekteeth of Steropodon galmani Archer et al., the oldest (Early Cretaceous) and most primitive Platypoda so far known. Similarly, one isolated lower molariform of the primitive gondwanathere Ferugliotherium windhauseni Bonaparte (Late Cretaceous) shows its anterolabial cusp connected by two ridges to two lingual cusps, forming a V-shaped, trigonid-like structureFacultad de Ciencias Naturales y Muse

"South American" marsupials from the late cretaceous of North America and the origin of marsupial cohorts

Newly described marsupial specimens of Judithian (late Campanian) and Lancian (Maastrichtian) age in the western interior of North America (Wyoming to Alberta) have dental morphologies consistent with those expected in comparably aged sediments in South America (yet to be found). Three new Lancian species are referable to the didelphimorphian Herpetotheriidae, which suggests that the ameridelphian radiation was well under way by this time. The presence of a polydolopimorphian from Lancian deposits with a relatively plesiomorphic dental morphology and an additional polydolopimorphian taxon from Judithian deposits with a more derived molar form indicate that this lineage of typically South American marsupials was diversifying in the Late Cretaceous of North America. This study indicates that typical South American lineages (e.g. didelphimorphians and polydolopimorphians) are not the result of North American peradectian progenitors dispersing into South America at the end of the Cretaceous (Lancian), or at the beginning of the Paleocene (Puercan), and giving rise to the ameridelphian marsupials. Instead, these lineages, and predictably others as well, had their origins in North America (probably in more southerly latitudes) and then dispersed into South America by the end of the Cretaceous. Geophysical evidence concerning the connections between North and South America in the Late Cretaceous is summarized as to the potential for overland mammalian dispersal between these places at those times. Paleoclimatic reconstructions are considered, as is the dispersal history of hadrosaurine dinosaurs and boid snakes, as to their contribution to an appraisal of mammalian dispersals in the Late Cretaceous. In addition, we present a revision of the South American component of the Marsupialia. One major outcome of this process is that the Polydolopimorphia is placed as Supercohort Marsupialia incertae sedis because no characteristics currently known from this clade securely place it within one of the three named marsupial cohorts.Fil: Case, Judd A.. Saint Mary's College of California; Estados UnidosFil: Goin, Francisco Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Departamento Científico de Paleontología de Vertebrados; ArgentinaFil: Woodburne, Michael O.. Museum of Northern Arizona; Estados Unido

Deep time diversity of metatherian mammals: implications for evolutionary history and fossil-record quality

Despite a global fossil record, Metatheria are now largely restricted to Australasia and South America. Most metatherian paleodiversity studies to date are limited to particular subclades, time intervals, and/or regions, and few consider uneven sampling. Here, we present a comprehensive new data set on metatherian fossil occurrences (Barremian to end Pliocene). These data are analyzed using standard rarefaction and shareholder quorum subsampling (including a new protocol for handling Lagerstätte-like localities). Global metatherian diversity was lowest during the Cretaceous, and increased sharply in the Paleocene, when the South American record begins. Global and South American diversity rose in the early Eocene then fell in the late Eocene, in contrast to the North American pattern. In the Oligocene, diversity declined in the Americas, but this was more than offset by Oligocene radiations in Australia. Diversity continued to decrease in Laurasia, with final representatives in North America (excluding the later entry of Didelphis virginiana) and Europe in the early Miocene, and Asia in the middle Miocene. Global metatherian diversity appears to have peaked in the early Miocene, especially in Australia. Following a trough in the late Miocene, the Pliocene saw another increase in global diversity. By this time, metatherian biogeographic distribution had essentially contracted to that of today. Comparison of the raw and sampling-corrected diversity estimates, coupled with evaluation of "coverage" and number of prolific sites, demonstrates that the metatherian fossil record is spatially and temporally extremely patchy. Therefore, assessments of macroevolutionary patterns based on the raw fossil record (as in most previous studies) are inadvisable.Facultad de Ciencias Naturales y Muse