First, we have four small mammals from Africa - the Democratic Republic of the Congo, to be exact. From one forest we have two new shrews and two new bats - small, yes, but important.
Then, we have a big one. This new tapir from Brazil, at over 100kg, is the largest new species of land mammal described since - well, a long time. Vietnam's saola is reportedly about 100kg. Depending how one counts reclassifications (and which reclassifications and taxonomic "splitting" events one counts), it might even be the biggest since the huge wild cattle species called the kouprey came out of Cambodia in 1937.
So, yeah, it's certainly the biggest mammal discovery of the 21st century. And it should serve as a wake-up call reminding us that there is still a lot to find in the remote places of the world. Espcially the Amazon, where Dr. Marc van Roosmalen has described several new species, including the 50-kg giant peccary, and reports several more large mammals seen but unclassified.
Here's the formal description. This animal is the fifth living species of tapir (there are some disagreements over tapir classification, but this animal is distinct: there's no doubting it).