Pará spiny tree-rat

The Pará spiny tree rat (Mesomys stimulax) or Surinam spiny tree rat, is a spiny rat species found in Brazil. Previously, Mesomys Stimulax's karyotype was 2n=60, Fundamental number (abbreviated FN), FN=116. However more recently the new karyotype has been found to be 2n=60, FN=110. This points to the idea that this species is most likely a species complex. References

Malcher, S. M., Pieczarka, J. C., Pereira, A. L., do Amaral, P. J. S., Rossi, R. V., Saldanha, J., & Nagamachi, C. Y. (2021). New karyotype for Mesomys stimulax (Rodentia, Echimyidae) from the Brazilian Amazon: A case for species complex?. Ecology and evolution, 11(12), 7125–7131. https://doi.org/10.1002/ece3.7583