Los alligatoroidea de Argentina: Una puesta al día de su registro fósil

The fossil record of Alligatoroidea in Argentina is mainly represented by Caimaninae alligatorids. This lineage recorded two impor- tant moments in its natural history, one at the beginning of the Paleogene (Late Paleocene–Middle Eocene) and the other in the Neogene (Late Miocene). The most ancient record of alligatoroids in South America comes from the Early Paleocene of Patagonia. It includes basal forms of caimanines such as Necrosuchus ionensis, Eocaiman palaeocenicus, Eocaiman cavernensis, and probably a new species of alligatoroid, which provide key morphological information on the evolutionary and biogeographic history of these crocodylians. Another important moment of the evolutionary history of caimanines is the diversification of the lineage observed during the Miocene. Although there is some isolated cranial material of caimanines from the Late Miocene of northwestern Argentina, the most abundant and diverse fossil Miocene material comes from the northeast, from a level informally called “Conglomerado Osífero”. Two genera of caimanines are known from this stratigraphic level (Caiman and Mourasuchus) with at least five valid species. Here we present an update of the knowledge of Cenozoic alligatorids of Argentina, as a tribute to Zulma Gasparini for her invaluable contribution to the understanding of the crocodilian evolution in South America.El registro fósil de Alligatoroidea en Argentina está representado mayormente por aligatóridos Caimaninae. Este linaje registra dos momentos importantes en su historia natural, uno en el comienzo del Paleógeno (Paleoceno tardío/Eoceno medio) y otro en el Neógeno (Mioceno tardío). El registro más antiguo de aligatoroideos en América del Sur proviene del Paleoceno temprano de Patagonia. Este registro es muy relevante porque incluye formas de caimaninos basales como Necrosuchus ionensis, Eocaiman palaeocenicus, Eocaiman cavernensis y probablemente una nueva especie de aligatoroideo, quienes proporcionan información morfológica clave en la historia evolutiva y biogeográfica de este grupo de crocodilianos. Otro momento importante de la historia evolutiva de los caimanines se observa durante el Mioceno, cuando este linaje se diversifica. Aunque hay algo de material craneano aislado del Mioceno tardío en el noroeste de Argentina, el material mioceno más abundante y diverso proviene del noreste, de un nivel informalmente llamado “Conglomerado Osífero”. De dicho nivel estratigráfico, se reconocen dos géneros de caimaninos (Caiman y Mourasuchus) con al menos cinco especies válidas. Aquí presentamos una actualización del conocimiento de los aligatóridos del Cenozoico de Argentina, en homenaje a Zulma Gasparini por su inestimable contribución a la comprensión de la evolución de los cocodrilos en América del Sur.Fil: Bona, Paula. 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. División Paleontología Vertebrados; ArgentinaFil: Barrios, Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Provincia del Neuquén. Municipalidad de Plaza Huincul. Museo "Carmen Funes"; Argentin

A new peirosaurid (Crocodyliformes, mesoeucrocodylia) from the Upper Cretaceous of Patagonia, Argentina

Fil: Barrios, Francisco. Museo Municipal Carmen Funes. Plaza Huincul. Neuquén; ArgentinaFil: Paulina-Carabajal, Ariana. Museo Municipal Carmen Funes. Plaza Huincul. Neuquén; ArgentinaFil: Bona, Paula. División Paleontología Vertebrados. Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; Argentin

Un nuevo peirosáurido (Crocodyliformes, Mesoeucrocodylia) del Cretácico Superior de Patagonia, Argentina

Peirosaurids are a group of Cretaceous continental crocodyliforms from Gondwana. Two species are known from the Neuquén Group in Argentina: Lomasuchus palpebrosus (Portezuelo Formation, late Turonian–early Coniacian) and Gasparinisuchus peirosauroides (Bajo de la Carpa and Anacleto formations, Santonian and early Campanian, respectively). Here, we describe the first peirosaurid from the Cerro Lisandro Formation, Bayomesasuchus hernandezi gen. et sp. nov. The material corresponds to a fragmentary skull and mandible. Although fragmentary, this is the most complete crocodyliform specimen recorded for the Cerro Lisandro Formation. In a phylogenetic analysis Bayomesasuchus is depicted in a polytomy together with South American peirosaurids and the African form Hamadasuchus rebouli.Los peirosáuridos constituyen un grupo de crocodiliformes continentales del Cretácico de Gondwana. Para el Grupo Neuquén, Argentina, se conocen dos especies: Lomasuchus palpebrosus (Formación Portezuelo, Turoniano tardío–Coniaciano temprano) y Gasparinisuchus peirosauroides (Formaciones Bajo de la Carpa y Anacleto, Santoniano y Campaniano temprano, respectivamente). Aquí, describimos el primer peirosáurido identificado para la Formación Cerro Lisandro, Bayomesasuchus hernandezi gen. et sp. nov. El material corresponde a cráneo y mandíbula fragmentarios. Aunque fragmentario, este es el espécimen de crocodiliforme más completo registrado para la Formación Cerro Lisandro. En un análisis filogenético, Bayomesasuchus es agrupado en una politomía junto con los peirosáuridos sudamericanos y la forma africana Hamadasuchus rebouli.Facultad de Ciencias Naturales y Muse

The austral components of the Neogene South American crocodylian fauna: the northeast Miocene-Pliocene Argentinean record

During the last years the knowledge about derived eusuchian crocodiles has been increased. Anatomical and phylogenetic approaches as well as new fossil records have lighted the evolutive and biogeographic history of several groups. In this way, paleontological research on Miocene-Pliocene South American taxa have provided new information that allowed supporting taxonomical and biogeographical hypotheses, many of them erected since the end of XIX century. The richest and more explored regions concerning Mio-Pliocene crocodylians in South America correspond to basins that surround the areas of Urumaco (Venezuela), La Venta (Colombia), Acre (Brazil), and Paraná (Northeast Argentina). Late Miocene-Pliocene fossils from Paraná were recovered from the "Conglomerado Osífero" (Ituzaingó Formation) and assigned to several taxa of Caimaninae (Alligatoroidea) and one Gavialoidea. Recent research has allowed exploring the taxonomical diversity of this fauna, including a descriptive revision and phylogenetic reanalysis of bizarre forms as Mourasuchus species. The Miocene-Pliocene "fauna" of crocodiles recorded in Northeastern Argentina differs from coeval ones of Northern South America by the absence of sebecids, crocodyloids, some alligatorid genera (as Purussaurus, Melanosuchus, and Paleosuchus), and by the rarity of gavialoid species. Giant forms, conspicuous in the Northern South American deposits, are virtually rare in the southern latitudes. Despite it, the austral South American crocodilian fauna exhibits strong affinities with that from the Northern Mio-Pliocene, sharing taxa at generic and even at specific levels (Gryposuchus neogaeus (Rusconi), Mourasuchus nativus (Gasparini), and Caiman latirostris (Daudin) [= C. cf. lutescens]). Such aquatic forms might indicate partial connections of drainage basins through swampy areas on their boundaries. These fresh water habits would have permitted migration of some of the crocodiles, but would have been an effective barrier for the migration of other taxa (e.g., cryptodirans turtles) as well as preclude the assumption of an intracontinental seaway link, as already proposed by some authors. Nevertheless, the historical factors that determinate the geographic patterns of distribution of crocodyles in South America should de evaluated in a biogeographical context.Simposio VII: Paleontología y biocronología del Terciario tardío de la MesopotamiaFacultad de Ciencias Naturales y Muse

Phylogenetic signal analysis in the basicranium of Ursidae (Carnivora, Mammalia)

Ursidae is a monophyletic group comprised of three subfamilies: Tremarctinae, Ursinae and Ailuropodinae, all of which have a rich geographical distribution. The phylogenetic relationships within the Ursidae group have been underexamined, especially regarding morphological traits such as the basicranium. Importantly, the basicranium is a highly complex region that covers a small portion of the skull, combining both structural and functional aspects that determine its morphology. Phylogenetic hypotheses of the Ursidae (including Tremarctinae) have been made based on morphological characters that considers skull, mandible and teeth features, while specific characters of the auditory region and basicranium have not been taken into account. To do this, we analyse the shape and size macroevolution of the basicranium of Ursidae, testing its morphological disparity in a phylogenetic context, which is quantified by means of the phylogenetic signal. We investigated phylogenetical autocorrelation by shape (depicted by Principal Components Analysis scores from previous published analyses) and basicranium size (depicted by centroid size, CS) using an orthonormal decomposition analysis and Abouheif C mean. The main advantages of these methods are that they rely exclusively on cladogram topology and do not require branch-length estimates. Also, an optimisation of the ancestral nodes was performed using TNT 1.5 software. In relation to the phylogenetic signal, both methods showed similar results: the presence of autocorrelation was detected in PC1 and PC2, while in PC3, PC4 and PC5 and in the size of the basicranium (CS), the absence of autocorrelation occurred. The most significant nodes (where there is autocorrelation) are the basal nodes ´Ursidae´ and ´Ursinae-Tremarctinae´. Within this last group, distinctive basicranium morphology is observed, being more conservative in Tremarctinae than in Ursinae. The differences between these subfamilies could be related to historical events involving varying food and environmental preferences. The high phylogenetic signal in the node Tremarctinae probably indicates that the basicranium configuration of these bears was obtained early in their evolutionary history. Finally, our results of the basicranium and skull length ratios indicate that in Tremarctinae, the basicranium size was not determined by phylogeny but instead by other factors, such as adaptive responses to climatic changes and competition with other carnivores.Fil: Arnaudo, Maria Eugenia. 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. División Paleontología Vertebrados; ArgentinaFil: Toledo, Néstor. 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: Soibelzon, Leopoldo Héctor. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de la Plata. Facultad de Cs.naturales y Museo. Laboratorio de Morfologia Evolutiva y Desarrollo.; ArgentinaFil: Bona, Paula. 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. División Paleontología Vertebrados; Argentin

Los Alligatoroidea de Argentina: una puesta al día de su registro fósil

The fossil record of Alligatoroidea in Argentina is mainly represented by Caimaninae alligatorids. This lineage recorded two important moments in its natural history, one at the beginning of the Paleogene (Late Paleocene–Middle Eocene) and the other in the Neogene (Late Miocene). The most ancient record of alligatoroids in South America comes from the Early Paleocene of Patagonia. It includes basal forms of caimanines such as Necrosuchus ionensis, Eocaiman palaeocenicus, Eocaiman cavernensis, and probably a new species of alligatoroid, which provide key morphological information on the evolutionary and biogeographic history of these crocodylians. Another important moment of the evolutionary history of caimanines is the diversification of the lineage observed during the Miocene. Although there is some isolated cranial material of caimanines from the Late Miocene of northwestern Argentina, the most abundant and diverse fossil Miocene material comes from the northeast, from a level informally called “Conglomerado Osífero”. Two genera of caimanines are known from this stratigraphic level (Caiman and Mourasuchus) with at least five valid species. Here we present an update of the knowledge of Cenozoic alligatorids of Argentina, as a tribute to Zulma Gasparini for her invaluable contribution to the understanding of the crocodilian evolution in South America.El registro fósil de Alligatoroidea en Argentina está representado mayormente por aligatóridos Caimaninae. Este linaje registra dos momentos importantes en su historia natural, uno en el comienzo del Paleógeno (Paleoceno tardío/Eoceno medio) y otro en el Neógeno (Mioceno tardío). El registro más antiguo de aligatoroideos en América del Sur proviene del Paleoceno temprano de Patagonia. Este registro es muy relevante porque incluye formas de caimaninos basales como Necrosuchus ionensis, Eocaiman palaeocenicus, Eocaiman cavernensis y probablemente una nueva especie de aligatoroideo, quienes proporcionan información morfológica clave en la historia evolutiva y biogeográfica de este grupo de crocodilianos. Otro momento importante de la historia evolutiva de los caimanines se observa durante el Mioceno, cuando este linaje se diversifica. Aunque hay algo de material craneano aislado del Mioceno tardío en el noroeste de Argentina, el material mioceno más abundante y diverso proviene del noreste, de un nivel informalmente llamado “Conglomerado Osífero”. De dicho nivel estratigráfico, se reconocen dos géneros de caimaninos (Caiman y Mourasuchus) con al menos cinco especies válidas. Aquí presentamos una actualización del conocimiento de los aligatóridos del Cenozoico de Argentina, en homenaje a Zulma Gasparini por su inestimable contribución a la comprensión de la evolución de los cocodrilos en América del Sur.Facultad de Ciencias Naturales y Muse

Neuroanatomy of Gryposuchus neogaeus (Crocodylia, Gavialoidea): a first integral description of the braincase and endocranial morphological variation in extinct and extant gavialoids

Fil: Bona, Paula. División Paleontología Vertebrados. Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; ArgentinaFil: Carabajal, Ariana Paulina. Instituto de Investigaciones en Biodiversidad y Medioambiente (INIBIOMA). Universidad Nacional del Comahue. San Carlos de Bariloche; ArgentinaFil: Brandoni de Gasparini, Zulma Nélida. División Paleontología Vertebrados. Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; Argentin

Neuroanatomy of <i>Gryposuchus neogaeus</i> (Crocodylia, Gavialoidea): a first integral description of the braincase and endocranial morphological variation in extinct and extant gavialoids

Morphological studies of the braincase and cranial endocast of fossil crocodylians, especially gavialids, are scarce. Here, we present a detailed description of the neuroanatomy of Gryposuchus neogaeus from the Miocene of Argentina, based on CT scans. The cranial endocast is sub-horizontal and the angle formed between the mid-brain and the hind-brain is poorly marked. When compared with Gavialis gangeticus, the mid-brain of G. neogaeus is relatively shorter, although the distribution of cranial nerves is similar. In the floor of the endocranial cavity, posterior to the dorsum sellae, there is a median foramen that leads into a canal that runs anteroventrally through the basisphenoid to penetrate the posterior wall of the pituitary fossa (open foramen for the basilar artery?). The same structure is present in G. gangeticus, but is absent in other living crocodylians, suggesting a potential synapomorphy of Gavialoidea. The pneumaticity of the skull roof and the lateral branches of the pharyngotympanic system in G. neogaeus are markedly reduced when compared with the extant species. Comparisons with the living Gavialis indicate that the pattern of braincase morphology of Gavialidae was present in the Miocene; however, the internal morphology, including brain shape, pneumaticity of the skull roof and basicranium, is different in the two species. This work is the first step to understand the variation of the neuroanatomy in this group of archosaurs and its palaeobiological implication.Facultad de Ciencias Naturales y Muse

Quality evaluation of minoxidil topical solutions obtained from magistral pharmacies

The objective of this study was to evaluate quality parameters of magistral topical solutions containing minoxidil (A, B and C), comparing the results with the ones obtained for the industrial formulation. Organoleptic tests, evaluation of the pH and density, centrifuge test, drug content determination, comparison of indicated dosage and in vitro follicular penetration of minoxidil were performed. Regarding the organoleptic properties, differences in color and viscosity were observed between the magistral (composed of minoxidil sulfate) and the industrial formulations (composed of minoxidil base). For pH values, the magistral solutions presented considerably more acidic pH, compared to the industrial sample. For the density test, the samples with the highest ethanol percentages (B and C) presented lower density. In the centrifuge test, none of the samples showed changes. Considering the drug content test, only the industrial sample and the magistral sample C showed drug percentage within the expected (90-110%), indicating lack of correction factor determination by the magistral pharmacies. Furthermore, it was observed that the dosage indicated by the magistral pharmacies do not correspond to the dose indicated by the industry, being significantly lower. All topical solutions tested presented hair follicle penetration of minoxidil, without statistical difference. The results indicate that there is a failure in the magistral pharmacies regarding the production and the indication of dosage of minoxidil topical solutions

Quality evaluation of minoxidil topical solutions obtained from magistral pharmacies

The objective of this study was to evaluate quality parameters of magistral topical solutions containing minoxidil (A, B and C), comparing the results with the ones obtained for the industrial formulation. Organoleptic tests, evaluation of the pH and density, centrifuge test, drug content determination, comparison of indicated dosages and in vitro follicular penetration of minoxidil were performed. Regarding the organoleptic properties, differences in color and viscosity were observed between the magistral (composed of minoxidil sulfate) and the industrial formulations (composed of minoxidil base). For pH values, the magistral solutions presented considerably more acidic pH, compared to the industrial sample. For the density test, the samples with the highest ethanol percentages (B and C) presented lower density. In the centrifuge test, none of the samples showed changes. Considering the drug content test, only the industrial sample and the magistral sample C showed drug percentage within the expected (90-110%), indicating lack of correction factor determination by the magistral pharmacies. Furthermore, it was observed that the dosage indicated by the magistral pharmacies do not correspond to the dose indicated by the industry, being significantly lower. All topical solutions tested presented hair follicle penetration of minoxildil, without statistical difference. The results indicate that there is a failure in the magistral pharmacies regarding the production and the indication of dosage of minoxidil topical solutions