Resumo Padrões cromossômicos são ferramentas valiosas em abordagens evolutivas. Apesar da notável expansão dos dados citogenéticos dos peixes, eles ainda são altamente deficientes para as espécies de águas oceânicas profundas, incluindo os membros da família Gempylidae. Espécies desta família são comercialmente importantes, compostas por predadores meso e bentopelágicos, cujas informações disponíveis sobre seu estilo de vida e padrões genéticos são muito limitadas. Este estudo apresenta os primeiros dados cromossômicos de duas espécies circumglobais desta família, Ruvettus pretiosus e Promethichthys prometheus, do Arquipélago de São Pedro e São Paulo. Foram utilizadas análises convencionais, coloração cromossômica com fluorocromos base-específicos e hibridização in situ por fluorescência (FISH) para o mapeamento de diferentes classes de DNA repetitivos. Ambas as espécies possuem 2n = 48 cromossomos, mas diferem significativamente quanto à fórmula cariotípica (FN = 50 e FN = 84). Os sítios 18S DNAr/Ag-RON e 5S DNAr têm um arranjo bi-telomérico sintênico em R. pretiosus, mas uma distribuição independente em P. prometheus. Os elementos transponíveis têm dispersão semelhante em ambas as espécies, enquanto os microssatélites estão agrupados nas regiões centroméricas e terminais de alguns cromossomos. Vale ressaltar que apesar da conservação do 2n basal dos Percomorpha, uma acentuada diversificação macro e microestrutural, mediada principalmente por inversões pericêntricas, diferencia os cariótipos das espécies, apontando para uma trajetória cromossômica particular dos gempilídeos entre os peixes marinhos. evolutivas profundas Gempylidae importantes bentopelágicos limitadas prometheus Paulo convencionais baseespecíficos base específicos FISH (FISH repetitivos n 4 cromossomos 5 84. 84 . 84) S DNAr/AgRON DNArAgRON DNAr/Ag RON Ag bitelomérico bi telomérico R P Percomorpha microestrutural pericêntricas marinhos 8 AgRON DNArAg

Abstract Chromosomal patterns are valuable tools in evolutionary approaches. Despite the remarkable expansion of fish cytogenetic data, they are still highly deficient concerning deep oceanic species, including the Gempylidae snake mackerels. The snake mackerels are important commercial species composed by meso- and bento-pelagic predators with very limited information available about their lifestyle and genetics patterns. This study presents the first chromosomal data of two circumglobal species of this family, Ruvettus pretiosus and Promethichthys prometheus, from the São Pedro and São Paulo Archipelago. Conventional analyses, chromosomal staining with base-specific fluorochromes, and fluorescence in situ hybridization (FISH) for mapping of repetitive DNA classes were used. Both species have 2n = 48 chromosomes, but they highly differ regarding the karyotype formula (FN = 50 and FN = 84). The 18S rDNA/Ag-NOR and the 5S rDNA sites have a syntenic bi-telomeric array in R. pretiosus, but an independent distribution in P. prometheus. The transposable elements are dispersed, while the microsatellites are also clustered in the centromeric and terminal regions of some chromosomes. It is noteworthy that despite the 2n conservation, a marked macro and microstructural diversifications, mainly mediated by pericentric inversions, differentiates the karyotypes of the species, pointing to a particular chromosomal trajectory of the gempylids among marine fish. approaches meso bentopelagic bento pelagic family prometheus Archipelago analyses basespecific base specific fluorochromes FISH (FISH used n 4 chromosomes 5 84. 84 . 84) S rDNA/AgNOR rDNAAgNOR rDNA/Ag NOR Ag bitelomeric bi telomeric R P dispersed conservation diversifications inversions 8 AgNOR rDNAAg

Abstract Epinephelidae (groupers) is an astonishingly diverse group of carnivorous fish widely distributed in reef environments around the world, with growing economic importance. The first chromosomal inferences suggested a conservative scenario for the family. However, to date, this has not been validated using biogeographic and phylogenetic approaches. Thus, to estimate karyotype diversification among groupers, eight species from the Atlantic and Indian oceans were investigated using conventional cytogenetic protocols and fluorescence in situ hybridization of repetitive sequences (rDNA, microsatellites, transposable elements). Despite the remarkable persistence of some symplesiomorphic karyotype patterns, such as all species sharing 2n=48 and most preserve a basal karyotype (2n=48 acrocentrics), the chromosomal diversification in the family revealed an unsuspected evolutionary dynamic, where about 40% of the species escape from the ancestral karyotype pattern. These karyotype changes showed a relation with the historical biogeography, likely as a byproduct of the progressive occupancy of new areas (huge diversity of adaptive and speciation conditions). In this context, oceanic regions harboring more recent clades such as those of the Indo-Pacific, exhibited a higher karyotype diversity. Therefore, the karyotype evolution of Epinephelidae fits well with the expansion and geographic contingencies of its clades, providing a more complex and diverse scenario than previously assumed.