The Trinidad Piping Guan, Pipile pipile synonym Aburria pipile (Jaquin, 1784) is the only endemic Cracid on the island of Trinidad. The species is currently listed as Critically Endangered and is considered to be in ‘on-going decline’ by the IUCN, BirdLife International and Cracid Specialist Group. This study aims to examine aspects of genetic variation and the evolution of the mitochondrial genome in the Trinidad Piping Guan utilising, for the first time, samples collected from individuals in the wild and reference specimens of the genus Pipile sourced from museum collections. In this study the complete mitochondrial genome of the Trinidad Piping Guan was sequenced for the first time. Analysis of intra-specific variation of wild Trinidad Piping Guan individuals using single nucleotide polymorphisms demonstrates extremely limited variation within the genes of the mitochondrial genome and nuclear gene intron sequences. Limited variation within this population is consistent with both historical and contemporary contractions of populations within a restricted island system, which may have serious implications for the future of this species in terms of both genetic diversity and conservation management. Phylogenetic analysis of the complete mitochondrial genome of the Trinidad Piping Guan enabled placement of the genus Pipile within the Galliforme evolutionary tree for the first time, and subsequently places the genus within the broader context of the Aves class. Mito-genomic analysis confirms that the Cracids are one of the basal Galliforme clades, and sister taxa to the Megapodidae. Phylogenetic placement of the Pipile genus is basal to that of the Crax species within the Cracidae family, indicative of an earlier evolutionary origin of the Piping Guans. The inclusion of the Trinidad Piping Guan, in the avian evolutionary tree using the whole mitochondrial genomes expands the current genetic phylogeny of the Cracid family, yielding a better understanding of evolutionary relationships among the Galliforme order and the diversification of modern avian lineages. This study has established novel molecular techniques for the analysis of mitochondrial DNA in historical specimens of the genus Pipile from museum reference collections. The analysis of inter-specific relationships within the genus Pipile has clarified the evolutionary and biogeographic relationships between the Piping Guan species. Additionally, the Trinidad Piping Guan is genetically defined for the first time as an evolutionarily significant unit, which represents a unique evolutionary pathway within this important genus in a closed island system on the island of Trinidad.

Cracídeos são aves neotropicais frugívoras e de grande porte. Englobam 50 espécies e 10 gêneros que podem ser agrupados em mutuns, jacus e jacutingas, aracuãs e Mutum Cornuto. Filogenias moleculares e estudos biogeográficos dos cracídeos estão disponíveis para as relações intergenéricas da família e entre as espécies de mutuns. Entretanto, não estão disponíveis dados moleculares para o estudo dos jacus e jacutingas. Os jacus e jacutingas englobam 23 espécies em 04 gêneros [Aburria, Chamaepetes, Penelope e Penelopina] com distribuição do México à Argentina. Neste estudo, definimos as relações filogenéticas entre as espécies do gênero Penelope, incluindo 13 espécies e 13 kb de seqüências de DNA mitocondrial e nuclear (análises Bayesiana e de Máxima Parcimônia) e entre as espécies do gênero Aburria (com Pipile), incluindo 5 espécies e 2,7 kb de seqüências de DNA mitocondrial (análises Bayesiana, de Máxima Verossimilhança e de Máxima Parcimônia). Nossos resultados mostraram Penelope como grupo monofilético e Pipile como grupo parafilético. Sugerimos que as espécies de Pipile sejam transferidas para o gênero Aburria, o gênero mais antigo. Em Penelope, as subespécies de Penelope obscura aparecem como grupo parafilético. Sugerimos que sejam consideradas como espécies válidas. No estudo evolutivo de Cracidae, as datações de tempo de divergência indicam que a diversificação dos jacus e jacutingas ocorreu do Mioceno ao Pleistoceno. As transgressões marinhas, o soerguimento dos Andes e suas conseqüências nas bacias dos rios sulamericanos, a formação da Laguna Amazônica e especializações de habitat parecem ser os principais fatores que influenciaram na diversificação dos jacus e jacutingas. / Cracids are large frugivorous Neotropical birds. Comprise 10 genera and 50 species that can be grouped as currasows, chachalacas, guans and Horned Guan. Molecular phylogenetic and biogeographic studies in this family were already performed for intergeneric relationships and among curassows species. Molecular data for intrageneric relationships for guans were not available. Guans comprise 23 species of four genera [Aburria, Chamaepetes, Penelope, and Penelopina] that range from México to Argentina. We estimated the phylogenetic relationships among species of the genus Penelope, including 13 species and about 13kb of mitochondrial and nuclear DNA (Bayesian and Maximum Parsimony) and among species of the genus Aburria (plus Pipile), including 5 species and about 2,7 kb of mitochondrial DNA (Bayesian, Maximum Likelihood and Maximum Parsimony). Results indicate Penelope as monophyletic and Pipile as paraphyletic group. Therefore, we suggest that Pipile should be merged with Aburria, the oldest described genus. For the genus Penelope: Penelope obscura, with three subspecies sampled, appears as paraphyletic group. We suggest that they should be considered as valid species. Molecular dating of divergence time was estimated. The diversification among guans seems to have occurred from Miocene to Pleistocene. Marine transgression, the rise of the Andes, and the subsequent changes in river basins in south America, formation of Amazon Lagoon and habitat specializations seems to be the major factors affecting guan diversification.

Cracídeos são aves neotropicais frugívoras e de grande porte. Englobam 50 espécies e 10 gêneros que podem ser agrupados em mutuns, jacus e jacutingas, aracuãs e Mutum Cornuto. Filogenias moleculares e estudos biogeográficos dos cracídeos estão disponíveis para as relações intergenéricas da família e entre as espécies de mutuns. Entretanto, não estão disponíveis dados moleculares para o estudo dos jacus e jacutingas. Os jacus e jacutingas englobam 23 espécies em 04 gêneros [Aburria, Chamaepetes, Penelope e Penelopina] com distribuição do México à Argentina. Neste estudo, definimos as relações filogenéticas entre as espécies do gênero Penelope, incluindo 13 espécies e 13 kb de seqüências de DNA mitocondrial e nuclear (análises Bayesiana e de Máxima Parcimônia) e entre as espécies do gênero Aburria (com Pipile), incluindo 5 espécies e 2,7 kb de seqüências de DNA mitocondrial (análises Bayesiana, de Máxima Verossimilhança e de Máxima Parcimônia). Nossos resultados mostraram Penelope como grupo monofilético e Pipile como grupo parafilético. Sugerimos que as espécies de Pipile sejam transferidas para o gênero Aburria, o gênero mais antigo. Em Penelope, as subespécies de Penelope obscura aparecem como grupo parafilético. Sugerimos que sejam consideradas como espécies válidas. No estudo evolutivo de Cracidae, as datações de tempo de divergência indicam que a diversificação dos jacus e jacutingas ocorreu do Mioceno ao Pleistoceno. As transgressões marinhas, o soerguimento dos Andes e suas conseqüências nas bacias dos rios sulamericanos, a formação da Laguna Amazônica e especializações de habitat parecem ser os principais fatores que influenciaram na diversificação dos jacus e jacutingas. / Cracids are large frugivorous Neotropical birds. Comprise 10 genera and 50 species that can be grouped as currasows, chachalacas, guans and Horned Guan. Molecular phylogenetic and biogeographic studies in this family were already performed for intergeneric relationships and among curassows species. Molecular data for intrageneric relationships for guans were not available. Guans comprise 23 species of four genera [Aburria, Chamaepetes, Penelope, and Penelopina] that range from México to Argentina. We estimated the phylogenetic relationships among species of the genus Penelope, including 13 species and about 13kb of mitochondrial and nuclear DNA (Bayesian and Maximum Parsimony) and among species of the genus Aburria (plus Pipile), including 5 species and about 2,7 kb of mitochondrial DNA (Bayesian, Maximum Likelihood and Maximum Parsimony). Results indicate Penelope as monophyletic and Pipile as paraphyletic group. Therefore, we suggest that Pipile should be merged with Aburria, the oldest described genus. For the genus Penelope: Penelope obscura, with three subspecies sampled, appears as paraphyletic group. We suggest that they should be considered as valid species. Molecular dating of divergence time was estimated. The diversification among guans seems to have occurred from Miocene to Pleistocene. Marine transgression, the rise of the Andes, and the subsequent changes in river basins in south America, formation of Amazon Lagoon and habitat specializations seems to be the major factors affecting guan diversification.