Development of a morphological key for the southern salt marsh harvest mouse using genetically verified individuals

Autor: Mark J. Statham, Laureen Barthman-Thompson, Susan Fresquez, Benjamin N. Sacks
Jazyk: angličtina
Rok vydání: 2021
Předmět:
Zdroj: California Fish and Wildlife Journal, Vol 107, Iss CESA Special Issue, Pp 367-381 (2021)
Druh dokumentu: article
ISSN: 2689-419X
2689-4203
DOI: 10.51492/cfwj.cesasi.22
Popis: The salt marsh harvest mouse (SMHM; Reithrodontomys raviventris) is a state and federally listed endangered species endemic to the coastal marshes of the San Francisco Estuary of California. Of two subspecies, the southern (R. r. raviventris) is most endangered and lacks reliable morphological field tools to distinguish from the sympatric western harvest mouse (WHM; R. megalotis). We trapped and collected genetic samples and morphological data from 204 harvest mice from 14 locations from across the range of the southern SMHM. Genetic species identification indicated these to be composed of 48 SMHM and 156 WHM, which we compared at ten morphological characters. Most continuous characters overlapped between species. Color characters were significantly differentiated and we identified a number of species-specific diagnostic pelage categories in both species. A random forest analysis indicated that ventral coloration of the abdomen and the ventral tail hair color were the most useful for differentiating between species. We used these two morphological characters to develop a decision tree which correctly classified 94% of harvest mice to species with 99% accuracy. These findings suggest that our decision tree can be used to reliably identify the species of most harvest mice in the range of the southern SMHM, with a small proportion (6% in our study) needing genetic confirmation. The decision tree should be tested on additional harvest mice that were not used in its development, particularly from novel locations across the range.
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