Fossil fishes from the Miocene La Venta fauna of the Magdalena River Valley, Colombia, are identified as Colossoma macropomum (Characidae), a living species from the Orinoco and Amazon basins. The fossils document a long and conservative history for a species that is highly specialized for feeding on streamside plants. The phylogenetically advanced position of Colossoma in the subfamily Serrasalminae implies that six related genera and other higher characid taxa originated well before 15 million years ago. This discovery also corroborates neontological evidence for a vicariance event that contributed species from Miocene Orinoco-Amazon faunas to the original Magdalena region fauna. The fossils suggest a formerly diverse Magdalena fauna that has suffered local extinction, perhaps associated with late Cenozoic tectonism. This new evidence may help explain the depauperate nature of the modern Magdalena River.
This research output has an Altmetric Attention Score of 5. This is our high-level measure of the quality and quantity of online attention that it has received. This Attention Score, as well as the ranking and number of research outputs shown below, was calculated when the research output was last mentioned on 26 August 2011.
All research outputs
#7,646,787
of 28,840,878 outputs
Outputs from Science
#50,816
of 87,350 outputs
Outputs of similar age
#3,569
of 12,799 outputs
Outputs of similar age from Science
#59
of 122 outputs
Altmetric has tracked 28,840,878 research outputs across all sources so far. This one has received more attention than most of these and is in the 72nd percentile.
So far Altmetric has tracked 87,350 research outputs from this source. They typically receive a lot more attention than average, with a mean Attention Score of 66.4. This one is in the 40th percentile – i.e., 40% of its peers scored the same or lower than it.
Older research outputs will score higher simply because they've had more time to accumulate mentions. To account for age we can compare this Altmetric Attention Score to the 12,799 tracked outputs that were published within six weeks on either side of this one in any source. This one has gotten more attention than average, scoring higher than 71% of its contemporaries.
We're also able to compare this research output to 122 others from the same source and published within six weeks on either side of this one. This one has gotten more attention than average, scoring higher than 50% of its contemporaries.
