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Leguminosae are one of the most diverse flowering-plant groups today, but the evolutionary history of the family remains obscure because of the scarce early fossil record, particularly from lowland tropics. Here, we report ~500 compression or impression specimens with distinctive legume features collected from the Cerrejón and Bogotá Formations, Middle to Late Paleocene of Colombia. The specimens were segregated into eight fruit and six leaf morphotypes. Two bipinnate leaf morphotypes are confidently placed in the Caesalpinioideae and are the earliest record of this subfamily. Two of the fruit morphotypes are placed in the Detarioideae and Dialioideae. All other fruit and leaf morphotypes show similarities with more than one subfamily or their affinities remain uncertain. The abundant fossil fruits and leaves described here show that Leguminosae was the most important component of the earliest rainforests in northern South America c. 60–58 million years ago. 

While modern forests have their origin in the diversification and expansion of angiosperms in the late Cretaceous and early Cenozoic, it is unclear if the rise of closed-canopy tropical rainforests preceded or followed the end-Cretaceous extinction. The “canopy effect” is a strong vertical gradients in the carbon isotope (δ13C) composition of leaves in modern closed-canopy forests that could serve as a proxy signature for canopy structure in ancient forests. To test this, we report measurements of the carbon isotope composition of nearly 200 fossil angiosperm leaves from two localities in the Paleocene Cerrejón Formation and one locality in the Maastrichtian Guaduas Formation. Leaves from one Cerrejón fossil assemblage deposited in a small fluvial channel exhibited a 6.3‰ range in δ13C, consistent with a closed-canopy forest. Carbon isotope values from lacustrine sediments in the Cerrejón Fm. had a range of 3.3‰, consistent with vegetation along a lake edge. An even narrower range of δ13C values (2.7‰) was observed for a leaf assemblage recovered from the Cretaceous Guaduas Fm., and suggests vegetation with an open canopy structure. Carbon isotope fractionation by late Cretaceous and early Paleogene leaves was in all cases similar to modern relatives, consistent with estimates of low atmospheric CO2 during this time period. This study confirms other lines of evidence suggesting closed-canopy forests in tropical South America existed by the late Paleocene, and fails to find isotopic evidence for a closed-canopy forest in the Cretaceous. 

Leguminosae are one of the most diverse flowering-plant groups today, but the evolutionary history of the family remains obscure because of the scarce early fossil record, particularly from lowland tropics. Here, we report ~500 compression or impression specimens with distinctive legume features collected from the Cerrejón and Bogotá Formations, Middle to Late Paleocene of Colombia. The specimens were segregated into eight fruit and six leaf morphotypes. Two bipinnate leaf morphotypes are confidently placed in the Caesalpinioideae and are the earliest record of this subfamily. Two of the fruit morphotypes are placed in the Detarioideae and Dialioideae. All other fruit and leaf morphotypes show similarities with more than one subfamily or their affinities remain uncertain. The abundant fossil fruits and leaves described here show that Leguminosae was the most important component of the earliest rainforests in northern South America c. 60–58 million years ago. 

ABSTRACT ObjectivesMost bipolar disorder (BD) patients initially present with depressive symptoms, resulting in a delayed diagnosis of BD and poor clinical outcomes. This study aims to identify features predictive of the conversion from Major Depressive Disorder (MDD) to BD by leveraging electronic health record (EHR) data from the Clínica San Juan de Dios Manizales in Colombia. MethodsWe employed a multivariable Cox regression model to identify important predictors of conversion from MDD to BD. ResultsAnalyzing 15 years of EHR data from 13,607 patients diagnosed with MDD, a total of 1610 (11.8%) transitioned to BD. Predictive features of the conversion to BD included severity of the initial MDD episode, presence of psychosis and hospitalization at first episode, family history of BD, and female gender. Additionally, we observed associations with medication classes (positive associations with prescriptions of mood stabilizers, antipsychotics, and negative associations with antidepressants) and a positive association with suicidality, a feature derived from natural language processing (NLP) of clinical notes. Together, these risk factors predicted BD conversion within 5 years of the initial MDD diagnosis, with a recall of 72% and a precision of 38%. ConclusionsOur study confirms previously identified risk factors identified through registry‐based studies (female gender and psychotic depression at the index MDD episode) and identifies novel ones (suicidality extracted from clinical notes). These results simultaneously demonstrate the validity of using EHR data for predicting BD conversion and underscore its potential for the identification of novel risk factors, thereby improving early diagnosis.