The fish order Pleuronectiformes (flatfishes) include over 800 fish species, and are generally considered to be monophyletic. Phylogenetic relationships within the order remain largely unresolved, particularly for the Paralichthyidae, a very poorly defined family. In addition to the lack of consensus on intrarelationships within this order, flatfish diversification patterns are still poorly understood. Here we want to test the hypothesis that (i) a densely sampled phylogenetic tree will help to unravel the phylogenetic relationships within flatfish, and (ii) that the formation of the Isthmus of Panama has played a role in the diversification of flatfish, following their distribution in both oceans, Atlantic and Pacific. Maximum likelihood and Bayesian analyzes were performed on a dataset consisting of nine mitochondrial and nuclear loci on a set of 309 flatfish species. The heterogeneity of substitution rates, known to cause phylogenetic errors in large multigene alignments, can be corrected by data partitioning, or by using heterogeneous site models. Very few studies have compared the effects of using these approaches. We present a robust phylogenetic tree with different heterogeneous and well-supported models, and the intraordinal relationships of flatfish are discussed in light of these results. We present evidence for three new suborders within the flatfishes. The monophyletic status of most families is corroborated. The family Paralichthyidae and the family Poecilopsettidae were found to be polyphyletic. Heterogeneous models have not been able to solve the deeper relationships between flatfish. We also show that flatfish diversification occurred in a few families in at least two stages, related to distinct geological events.

The Neogene history of Caribbean deep-sea benthic foraminifera was investigated by calculating changes in paleoproductivity, diversity and paleobiogeography ~26 to 2 Ma, which includes the progressive closure of the Central American Seaway. Three hypotheses were tested: (1) Paleoproductivity values prior to closure of the Central American Seaway are similar in both the Caribbean and equatorial Pacific and then diverge by the time of early shoaling events; (2) Diversity values of benthic foraminifera prior to the closure of the Central American Seaway were similar in the Caribbean and EEP, and had changed by the time of early shoaling; and (3) during the Miocene and into the Pleistocene, the progressive constriction of the CAS affected deep-sea benthic foraminiferal assemblages by increasing their dissimilarity between the Caribbean and equatorial Eastern Pacific. These hypotheses were tested with 104 samples from five Caribbean and EEP deep-sea cores by calculating paleoproductivity with multiple proxies, determining diversity indices and calculating biogeographic similarity coefficients. The data supported the first two hypotheses: The greatest change in paleoproductivity occurred at ~8 Ma during seaway constriction, when values diverged between the Caribbean and EEP. After complete seaway closure at ~4 Ma, the Caribbean became oligotrophic, noted by a decrease in high-organic flux species, and an increase in Nuttalides umbonifera, an indicator species. The largest changes in species-level diversity occurred with the barrier to deep-water flow at ~12 Ma, and Caribbean diversity increased at ~8 Ma with seaway constriction. However, the third hypothesis was rejected: Increases in assemblage similarity actually occurred during most major paleoceanographic events, with the only decrease in Caribbean-EEP similarity occurring at ~12 Ma, coincident with a drop in diversity and emplacement of the Panama isthmian sill. Thus, the barrier to deep-water flow at ~12 Ma affected the composition of tropical American benthic foraminifera more than the largest change in paleoproductivity at ~8 Ma, or closure of the Central American Seaway at ~4 Ma.

This dissertation provides both an historical outline and contemporary ethnographic account of the Panamanian musical practice called “música típica popular,” which is commonly understood in Panama to denote a specific kind of vernacular music that is widely embraced. By examining the social-historical processes, events and discourses that have contributed to the genre’s development, this study seeks to develop greater understanding of what I argue is this music’s particular and pronouncedly ambiguous relationship to prominent themes of Panamanian cultural nationalism. Specifically, I endeavour to show that early on in its history música típica popular epitomized Panama’s (liberalist-identified) national ethos of progressive modernity and cultural cosmopolitanism while at the same time maintaining alignments to specific territories and musical practices significant to Panamanian vernacular imaginaries. The historical outline covers música típica popular’s development beginning from the late nineteenth century to the present. Its focus is on the genre’s tandem commercialisation and massification, performance and production technologies and associated performance modalities, shared musical/sonic traits, repertoire and approaches to innovation through musical mixing or fusión (fusion). One of the central goals here is to trace and examine points of alignment between música típica popular and dominant paradigms governing isthmian geo-cultural self-identification—particularly the interplay between a rural-identified “vernacular” culture and the perceived urban cosmopolitanism of Panamanian metropolites. Through ethnographic research this study also aims to examine the various sonic, social and economic factors that contribute to notions of música típica popular as a particular socio-musical collectivity actively in dialogue with discourses of Panamanian national and cultural identity. To this end, notions of “genre” and “style” provide an analytical framework particularly for coming to terms with the interplay between sensibilities of convention and common practice, and a need for meaningful differentiation among practitioners. It is my contention that while música típica popular practitioners actively cultivate links both to themes of Panamanian music-cultural vernacularism and cosmopolitanism, on the whole the relationship of the genre to nationalist discourse should be more properly understood as one of sustained ambiguity: not wholly aligned to one theme or the other, and in fact doggedly and often productively resistant to such binary categorizations.

This dissertation provides both an historical outline and contemporary ethnographic account of the Panamanian musical practice called “música típica popular,” which is commonly understood in Panama to denote a specific kind of vernacular music that is widely embraced. By examining the social-historical processes, events and discourses that have contributed to the genre’s development, this study seeks to develop greater understanding of what I argue is this music’s particular and pronouncedly ambiguous relationship to prominent themes of Panamanian cultural nationalism. Specifically, I endeavour to show that early on in its history música típica popular epitomized Panama’s (liberalist-identified) national ethos of progressive modernity and cultural cosmopolitanism while at the same time maintaining alignments to specific territories and musical practices significant to Panamanian vernacular imaginaries. The historical outline covers música típica popular’s development beginning from the late nineteenth century to the present. Its focus is on the genre’s tandem commercialisation and massification, performance and production technologies and associated performance modalities, shared musical/sonic traits, repertoire and approaches to innovation through musical mixing or fusión (fusion). One of the central goals here is to trace and examine points of alignment between música típica popular and dominant paradigms governing isthmian geo-cultural self-identification—particularly the interplay between a rural-identified “vernacular” culture and the perceived urban cosmopolitanism of Panamanian metropolites. Through ethnographic research this study also aims to examine the various sonic, social and economic factors that contribute to notions of música típica popular as a particular socio-musical collectivity actively in dialogue with discourses of Panamanian national and cultural identity. To this end, notions of “genre” and “style” provide an analytical framework particularly for coming to terms with the interplay between sensibilities of convention and common practice, and a need for meaningful differentiation among practitioners. It is my contention that while música típica popular practitioners actively cultivate links both to themes of Panamanian music-cultural vernacularism and cosmopolitanism, on the whole the relationship of the genre to nationalist discourse should be more properly understood as one of sustained ambiguity: not wholly aligned to one theme or the other, and in fact doggedly and often productively resistant to such binary categorizations.