| Robust cottontail | |
|---|---|
| |
| S. h. robustus in Big Bend National Park | |
Scientific classification 
| |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Lagomorpha |
| Family: | Leporidae |
| Genus: | Sylvilagus |
| Species: | S. holzneri
|
| Binomial name | |
| Sylvilagus holzneri (Mearns, 1896)
| |
| Subspecies | |
| |
| |
| Range of subspecies S. h. robustus | |
| Synonyms | |
|
Sylvilagus cognatus Nelson, 1907 | |
The robust cottontail or Holzner's cottontail (Sylvilagus holzneri) is a species of cottontail rabbit native to high-altitude regions of the southwestern United States and western Mexico.[2]
This species and the subspecies comprising it were long considered to be subspecies of the eastern cottontail (S. floridanus), but were promoted to species level due to morphological analysis.[3][4] Genetic data have confirmed the uniqueness of S. holzneri.[5] S. holzneri and S. floridanus are distinguished primarily by size, dental, and cranial differences.
According to genetic analysis, there are three subspecies of S. holzneri:[3]
All three of these were previously considered subspecies of S. floridanus. One (robustus) was already resurrected as a distinct species in 1998, and was considered as such until being reclassified as a subspecies of the newly-resurrected holzneri in 2021, with the common name "robust cottontail" carrying over to holzneri.[2][6]
The Manzano Mountain cottontail (S. cognatus) was a species of Sylvilagus also previously classified in S. floridanus, until it was later reclassified as a distinct species. This species was thought to be restricted to the Manzano Mountains in New Mexico, where it occurs in coniferous forests in high elevation, and was classified as Endangered by the IUCN Red List. However, a 2021 phylogenetic analysis found S. cognatus to be indistinguishable from S. h. holzneri and synonymized it with holzneri. This classification was followed by the American Society of Mammalogists.[3][2]
S. holzneri typically averages a total length of 42 cm, and weighs between 1.3 and 1.8 kg.[7] It is restricted to dry, brushy, mountains at elevations above 1500 meters.[7]
Despite the rarity of S. h. robustus, currently no governmental agency provides protection or listing for this subspecies.[1]
