Evolutionary and Biogeographical History of Penguins (Sphenisciformes): Review of the Dispersal Patterns and Adaptations in a Geologic and Paleoecological Context

Despite its current low diversity, the penguin clade (Sphenisciformes) is one of the groups of birds with the most complete fossil record. Likewise, from the evolutionary point of view, it is an interesting group given the adaptations developed for marine life and the extreme climatic occupation capacity that some species have shown. In the present contribution, we reviewed and integrated all of the geographical and phylogenetic information available, together with an exhaustive and updated review of the fossil record, to establish and propose a biogeographic scenario that allows the spatialtemporal reconstruction of the evolutionary history of the Sphenisciformes, discussing our results and those obtained by other authors. This allowed us to understand how some abiotic processes are responsible for the patterns of diversity evidenced both in modern and past lineages. Thus, using the BioGeoBEARS methodology for biogeographic estimation, we were able to reconstruct the biogeographical patterns for the entire group based on the most complete Bayesian phylogeny of the total evidence. As a result, a New Zealand origin for the Sphenisciformes during the late Cretaceous and early Paleocene is indicated, with subsequent dispersal and expansion across Antarctica and southern South America. During the Eocene, there was a remarkable diversification of species and ecological niches in Antarctica, probably associated with the more temperate climatic conditions in the Southern Hemisphere. A wide morphological variability might have developed at the beginning of the Paleogene diversification. During the Oligocene, with the trends towards the freezing of Antarctica and the generalized cooling of the Neogene, there was a turnover that led to the survival (in New Zealand) of the ancestors of the crown Sphenisciform lineages. Later these expanded and diversified across the Southern Hemisphere, strongly linked to the climatic and oceanographic processes of the Miocene. Finally, it should be noted that the Antarctic recolonization and its hostile climatic conditions occurred in some modern lineages during the Pleistocene, possibly due to exaptations that made possible the repeated dispersion through cold waters during the Cenozoic, also allowing the necessary adaptations to live in the tundra during the glaciations.Fil: Pelegrín, Jonathan S.. Universidad Santiago de Cali; ColombiaFil: Acosta Hospitaleche, Carolina Ileana Alicia. 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; Argentin

A PHYLOGENETIC PERSPECTIVE OF THE AVIAN TROPHIC DIVERSIFICATION: INTEGRATING PALAEONTOLOGICAL AND NEONTOLOGICAL INFORMATION

From their origin in the Middle Jurassic until the present, birds have undergone one of the most important evolutionary radiations among vertebrates, with the development of great species-level diversity and the occupation of a broad spectrum of ecological niches. Since dietary shifts involve a series of morphophysiological adjustments and reflect the use of the resources, diet represents a key ecological and evolutionary parameter to understand the history of bird clades. This study combines neontological and paleontological dietary information in a phylogenetic context, aiming the understanding the role of feeding habits in bird evolution and their potential relationship with past ecological and evolutionary events. Our findings point towards an omnivorous ancestral diet for the avian clade, which is consistent with dietary information, dental structure and life style of the first birds, such as Archaeopteryx. Our results also show dietary shifts in avian evolutionary history. Faunivores predominate in the avian history, while herbivorous lineages underwent adaptive radiations possibly related to transformation of ecosystems and their plant assemblages worldwide such as the development of the angiosperms during the Cretaceous or the development of grassy environments in the Oligocene. Faunivorous and herbivorous clades arose basically through diversification within lineages, while omnivores evolved due to transitions into the strategy. The capacity to specialize and generate new trophic niches allowed faunivores and herbivores to diversify more than omnivores. Nevertheless, despite this relatively low diversification, the omnivorous strategy appears to be key to the primary processes of bird radiation and fundamental in the evolutionary success of birds.Peer reviewe

A phylogenetic study to assess the link between biome specialization and diversification in swallowtail butterflies

The resource-use hypothesis, proposed by E.S. Vrba, states that habitat fragmentation caused by climatic oscillations would affect particularly biome specialists (species inhabiting only one biome), which might show higher speciation and extinction rates than biome generalists. If true, lineages would accumulate biome-specialist species. This effect would be particularly exacerbated for biomes located at the periphery of the global climatic conditions, namely, biomes that have high/low precipitation and high/low temperature such as rainforest (warm-humid), desert (warm-dry), steppe (cold-dry) and tundra (cold-humid). Here, we test these hypotheses in swallowtail butterflies, a clade with more than 570 species, covering all the continents but Antarctica, and all climatic conditions. Swallowtail butterflies are among the most studied insects, and they are a model group for evolutionary biology and ecology studies. Continental macroecological rules are normally tested using vertebrates, this means that there are fewer examples exploring terrestrial invertebrate patterns at global scale. Here, we compiled a large Geographic Information System database on swallowtail butterflies' distribution maps and used the most complete time-calibrated phylogeny to quantify diversification rates (DRs). In this paper, we aim to answer the following questions: (1) Are there more biome-specialist swallowtail butterflies than biome generalists? (2) Is DR related to biome specialization? (3) If so, do swallowtail butterflies inhabiting extreme biomes show higher DRs? (4) What is the effect of species distribution area? Our results showed that swallowtail family presents a great number of biome specialists which showed substantially higher DRs compared to generalists. We also found that biome specialists are unevenly distributed across biomes. Overall, our results are consistent with the resource-use hypothesis, species climatic niche and biome fragmentation as key factors promoting isolation

Evolutionary and Biogeographical History of Penguins (Sphenisciformes): Review of the Dispersal Patterns and Adaptations in a Geologic and Paleoecological Context

Despite its current low diversity, the penguin clade (Sphenisciformes) is one of the groups of birds with the most complete fossil record. Likewise, from the evolutionary point of view, it is an interesting group given the adaptations developed for marine life and the extreme climatic occupation capacity that some species have shown. In the present contribution, we reviewed and integrated all of the geographical and phylogenetic information available, together with an exhaustive and updated review of the fossil record, to establish and propose a biogeographic scenario that allows the spatial-temporal reconstruction of the evolutionary history of the Sphenisciformes, discussing our results and those obtained by other authors. This allowed us to understand how some abiotic processes are responsible for the patterns of diversity evidenced both in modern and past lineages. Thus, using the BioGeoBEARS methodology for biogeographic estimation, we were able to reconstruct the biogeographical patterns for the entire group based on the most complete Bayesian phylogeny of the total evidence. As a result, a New Zealand origin for the Sphenisciformes during the late Cretaceous and early Paleocene is indicated, with subsequent dispersal and expansion across Antarctica and southern South America. During the Eocene, there was a remarkable diversification of species and ecological niches in Antarctica, probably associated with the more temperate climatic conditions in the Southern Hemisphere. A wide morphological variability might have developed at the beginning of the Paleogene diversification. During the Oligocene, with the trends towards the freezing of Antarctica and the generalized cooling of the Neogene, there was a turnover that led to the survival (in New Zealand) of the ancestors of the crown Sphenisciform lineages. Later these expanded and diversified across the Southern Hemisphere, strongly linked to the climatic and oceanographic processes of the Miocene. Finally, it should be noted that the Antarctic recolonization and its hostile climatic conditions occurred in some modern lineages during the Pleistocene, possibly due to exaptations that made possible the repeated dispersion through cold waters during the Cenozoic, also allowing the necessary adaptations to live in the tundra during the glaciations

The macroevolutionary role of migration for bird occupation of biomes with adverse climatic conditions

Comunicación presentada en el XIII Encuentro en Jóvenes Investigadores en Paleontología (XIII EJIP) - XIII Meeting of Early-Stage Researchers in Paleontology (XIII EJIP): Cercedilla, 15 - 18 de Abril de 2015Peer reviewe

Ecological specialization and macroevolutionary patterns: First test of resource-use hypothesis in marine vertebrates (Cetacea, Mammalia)

Trabajo presentado en II Joint Congress on Evolutionary Biology (Evolution), celebrado en Montpellier (Francia), del 19 al 22 de agosto de 2018The resource-use hypothesis developed by Vrba predicts that specialist species have higher speciation and extinction rates than generalist ones, due to their higher susceptibility to resource restriction, which makes them more sensitive to environmental change, vicariance and directional selection. Here, we present the first test of the resource-use hypothesis in marine organisms (Cetacea). We identified 6 different marine biomes, based on biotic and abiotic variables. Using distribution data, we estimated the occupation of biomes for each species and the total number of occupied biomes (the biome specialization index, BSI). To test the resource-use hypothesis, we run 10,000 Montecarlo randomizations of the observed data, and compare the randomized distribution of BSI values with the observed ones. Besides, we developed a phylogenetic likelihood-based method (QuaSSE) for testing whether the degree of biomic specialization affects speciation rates in Cetacean lineages. Results are consequent with the hypothesis predictions: 1) we found more specialists than expected by chance, 2) higher proportions of specialists than expected by chance were associated to biomes at the extreme of the primary production gradient, and 3) there were differences in the biome occupancies between Odotoceti and Mysticeti. These results reveal the relevance of the diverse ecological and physiological requirements among species and between the two big groups of Cetacea for their evolution.Peer reviewe