Roman-Palacios, C. | Search bioRxiv

bioRxiv2020

Decolonizing Psocopteran Systematics: Holarctic Lineages Cannot Inform Diversity and Evolution in Tropics

Despite tropical psocids comprise ~60% of species diversity within the Psocidae (Insecta, Psocodea), previous studies on the Psocidae phylogeny have poorly sampled tropical species (<40% species in trees). Here we discuss the evolution and systematics of the Psocidae based on the most comprehensive species-level sampling of the Psocidae. We sequenced and inferred the phylogenetic position of 43 previously unsampled Neotropical species from COI, H3, WNT, 18S, 16S, and 12S. Based on our phylogenies we found that Neotropical psocids are generally not closely related to morphologically similar taxa in the Holarctic region. Consequently, the monophyletic status for the major groups within Psocidae (subfamilies and tribes) is recovered only when Holarctic groups are sampled (7-10 of 11 higher-level groups are monophyletic) but violated when Neotropical species are included in the dataset (1 of 11 higher-level groups are monophyletic). Leveraging the largest phylogeny of the Psocidae, our study pinpoints the downfalls of simply extending taxonomic knowledge from lineages of a certain area to inform diversity and evolution of lineages in other regions. HighlightsO_LITropical psocids comprise >60% of the extant family richness C_LIO_LIPrevious phylogenies have undersampled Tropical psocids C_LIO_LIHolarctic and Neotropical species are classified under the same morphological groups C_LIO_LIHolarctic and Neotropical generally correspond to evolutionarily distinct lineages C_LIO_LIPhylogenies based on Holarctic psocids poorly inform evolution in the Neotropics C_LI

evolutionary biology↗

bioRxiv2019

Evolutionary time explains the global distribution of freshwater fish diversity

AimThe evolutionary causes of the latitudinal diversity gradient are debated. Hypotheses have ultimately invoked either faster rates of diversification in the tropics, or more time for diversification due to the tropical origins of higher taxa. Here we perform the first test of the diversification rate and time hypotheses in freshwater ray-finned fishes, a group comprising nearly a quarter of all living vertebrates. LocationGlobal. Time period368-0 mya. Major taxa studiedExtant freshwater ray-finned fishes. MethodsUsing a mega-phylogeny of actinopterygian fishes and a global database of occurrence records, we estimated net diversification rates, the number of colonizations and regional colonization times of co-occurring species in freshwater drainage basins. We used Generalized Additive Models to test whether these factors were related to latitude. We then compared the influence of diversification rates, colonization numbers, colonization times and surface area on species richness, and how these factors are related to each other. ResultsWhile both diversification rates and time were related to richness, time had greater explanatory power and was more strongly related to latitude than diversification rates. Other factors (basin surface area, number of colonizations) also helped explain richness but were unrelated to latitude. The worlds most diverse freshwater basins (Amazon, Congo rivers) were dominated by lineages with Mesozoic origins. The temperate groups dominant today arrived near the K-Pg boundary, leaving comparatively less time to build richness. Diversification rates and colonization times were inversely related: recently colonized basins had the fastest rates, while ancient species-rich faunas had slower rates. Main conclusionsWe concluded that time is the lead driver of latitudinal richness disparities in freshwater fish faunas. We suggest that the most likely path to building very high species richness is through diversification over long periods of time, rather than diversifying quickly.

evolutionary biology↗