A shrew recorded in Oaxaca, Mexico. Its current name is Cryptotis magnus; a 2007 account used the earlier form C. magna.
The older account of C. magna describes dark brown upperparts and a somewhat paler underside.
Cryptotis magnus is relatively large among its North American relatives and has a long tail. It lives in mountain cloud forest in Oaxaca, Mexico. Its cells contain chromosomes, the structures that carry genetic information.
A study published in 2023 examined wild specimens from forest near Santa Catarina Ixtepeji at 2,304 metres. Researchers stained bone-marrow cells and selected eight clear metaphase images for counting. They found 26 chromosomes, including 24 autosomes and two sex chromosomes.
All 24 autosomes had arms extending on both sides of the centromere. Their shapes, as well as their number, help characterize the species. The authors proposed that chromosome fusion could explain the low number, while identifying its evolutionary origin as a question for further study.
An extinction-risk assessment has not been added yet.
The IUCN global assessment dated 11 July 2016 and published in 2018 listed this species under the name Cryptotis magna as Vulnerable (VU). It identified deforestation for agriculture and urban development as causes of habitat fragmentation and declining habitat extent and quality. Retaining forest and limiting fragmentation within its restricted Oaxacan range are conservation priorities.