2008/05/20 by Virginie Millien · 2 citations
Agricultural and Biological Sciences · Earth and Planetary Sciences · Mathematics · #Bat Biology and Ecology Studies #Biology #Ecology #Evolution and Paleontology Studies #Geography #Morphological variations and asymmetry #Rodent
paper · doi:10.1098/rspb.2008.0087
openalex publication_date 2008/05/20 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
can actually be used as a reference sample.The analysis reveals that given the size of its upper dentition, the skull of J. monesi was 45% longer than expected from the sample of 35 species I used here (figure 1).The body mass estimates from skull length measurements such as the ones used in R&B (2008) may thus be greatly overestimated (out of the seven measurements in R&B (2008), five were taken along the longitudinal axis of the skull).Therefore, J. monesi does not fit an extant rodent model and body mass estimates for this species should be considered with caution.Whether J. monesi has a very elongated skull or a very short tooth row (microdonty) cannot be assessed at this point; we would need to compare the skull and teeth proportions with independent measurements, such as long bone measurements.Another possibility may be to compare J. monesi with extant herbivores comparable in size such as small artiodactyls.The paper published by R&B ( 2008) reports a remarkable finding which widens our vision of rodent ecology and the evolution of this group of mammals.One recommendation is that future efforts should be made to take into account sources of error when estimating the body mass of extinct species.This is true not only for J. monesi, but also for other giant fossil rodents such as P. pattersoni (V.Millien & H. Bovy 2008, unpublished manuscript).In conclusion, J. monesi is certainly the largest rodent ever described, but, based on these calculations, its body mass may have been as low as 350 kg.