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Crotalus pyrrhus

(Cope, 1867 [1866])

Southwestern Speckled Rattlesnake

G5Secure Found in 20 roadless areas NatureServe Explorer →
G5SecureGlobal Rank
LowThreat Impact
Identity
Unique IDELEMENT_GLOBAL.2.1146769
Element CodeARADE02160
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVertebrate Animal
Endemicoccurs (regularly, as a native taxon) in multiple nations
KingdomAnimalia
PhylumCraniata
ClassReptilia
OrderSquamata
FamilyViperidae
GenusCrotalus
Concept Reference
Meik J. M., J. W. Streicher, A. M. Lawing, O. Flores-Villela, and M. K. Fujita. 2015. Limitations of climatic data for inferring species boundaries: insights from speckled rattlesnakes. PLoS ONE 10(6): e0131435. doi:10.1371/journal.pone.0131435
Taxonomic Comments
Meik et al. (2015), using multilocus sequence and phenotypic data, demonstrated that Crotalus pyrrhus is a species distinct from C. mitchellii of Baja California.

The traditional view of rattlesnake taxonomy that recognizes the two monophyletic sister genera Crotalus and Sistrurus (e.g. Brattstrom 1964) has recently been challenged. Stille (1987) and McCranie (1988) presented data that suggested Sistrurus is not monophyletic and rendered Crotalus paraphyletic. Parkinson (1999) found Sistrurus monophyletic but its position rendered Crotalus paraphyletic. Knight et al. (1993) used mtDNA to defend the traditional generic taxonomy, but in order to do so ignored the most parsimonious tree. The genus Crotalus is monophyletic when including the Mexican C. ravus (Murphy et al. 2002), and is supported as such in most recent phylogenies, as well as being the sister taxon to a monophyletic Sistrurus (e.g., Pyron et al. 2013) (Crother 2017).
Conservation Status
Rank Method Rank calculation - Biotics v2
Review Date2021-08-18
Change Date2021-08-18
Edition Date2021-08-18
Edition AuthorsOrmes, M. (2021)
Threat ImpactLow
Range Extent200,000-2,500,000 square km (about 80,000-1,000,000 square miles)
Number of Occurrences81 - 300
Rank Reasons
This species is widespread, common, known from many localities, and does not appear to be declining.
Range Extent Comments
This species ranges from the northern half of the Baja California Peninsula, Mexico, extending into the southwestern United States (southern California, southern Nevada, western Arizona, and southwestern Utah); also El Muerto and Smith Islands, Mexico, in the western Sea of Cortez (Meik and Babb 2020).
Occurrences Comments
This species is represented by a large number of occurrences (subpopulations) (e.g., see maps in Campbell and Lamar 2004, Holycross and Mitchell 2020).
Threat Impact Comments
Rangewide, no major threats are known. Some populations may have been impacted by habitat destruction, automobile traffic, and/or direct killing by humans, especially in conjunction with "rattlesnake roundups." Compared to similar species, C. pyrrhus appears to have a higher survival rate in habitat fragments, including those that receive heavy recreational use (Meik and Babb 2020).
Ecology & Habitat

Description

A medium-sized pit viper that generally attains body lengths of less than a meter, although it ranges from about 92 to130 centimeters (Klauber 1936, Cochran et al. 2021).

Habitat

This species is most commonly associated with the rugged and rocky terrain of the mountains of the Mojave and Sonoran deserts and is rarely encountered in the adjacent desert flats (Klauber 1936, Cochran et al. 2021). The primary habitat are the rocky lower slopes and canyons, but it is also found in seeps, springs, as well as riparian habitats when available. When inactive, it occurs under rocks or bushes or in crevices, caves, abandoned mines, rodent burrows, or woodrat nests (Meik and Babb 2020).
Terrestrial Habitats
Woodland - ConiferShrubland/chaparralDesertBare rock/talus/scree
Palustrine Habitats
Riparian
Other Nations (1)
United StatesN5
ProvinceRankNative
UtahS3Yes
ArizonaS5Yes
NevadaS4Yes
CaliforniaSNRYes
Threat Assessments
ThreatScopeSeverityTiming
No known threats———

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Roadless Areas (20)
California (20)
AreaForestAcres
Cactus Springs BSan Bernardino National Forest3,106
Cahuilla MountainSan Bernardino National Forest6,952
CalienteCleveland National Forest5,953
ColdwaterCleveland National Forest8,402
Crystal CreekSan Bernardino National Forest6,783
Cutca ValleyCleveland National Forest14,530
Deep CreekSan Bernardino National Forest23,869
Eagle PeakCleveland National Forest6,481
Granite PeakSan Bernardino National Forest450
Hixon FlatSan Bernardino National Forest8,095
LaddCleveland National Forest5,300
Mill PeakSan Bernardino National Forest7,884
No NameCleveland National Forest4,897
Pine CreekCleveland National Forest503
Pyramid Peak BSan Bernardino National Forest7,194
Raywood Flat BSan Bernardino National Forest11,373
Rouse HillSan Bernardino National Forest13,745
Sill HillCleveland National Forest5,294
TrabucoCleveland National Forest23,341
WildhorseCleveland National Forest1,483
References (15)
  1. Brattstrom, B. H. 1964. Evolution of the pit vipers. Transactions of the San Diego Society of Natural History 13(11):185-268.
  2. Campbell, J. A., and W. W. Lamar. 2004. The venomous reptiles of the Western Hemisphere. 2 volumes. Cornell University Press.
  3. Cochran, C., K.L. Edwards, Z.D. Travis, L.R. Pompe, and W.K. Hayes. 2021. Diet and feeding frequency in the Southwestern Speckled Rattlesnake (<i>Crotalus pyrrhus</i>): ontogenetic, sexual, geographic, and seasonal variation. Journal of Herpetology 55(1): 77-87.
  4. Crother, B. I. (editor). 2017. Scientific and standard English names of amphibians and reptiles of North America north of Mexico, with comments regarding confidence in our understanding. 8th edition. SSAR Herpetological Circular 43:1-104. [Updates in SSAR North American Species Names Database at: https://ssarherps.org/cndb]
  5. Global Biodiversity Information Facility (GBIF). 2021. GBIF data accessed through GeoCAT portal. Online. Available: http://geocat.kew.org/ (accessed 2021).
  6. Holycross, A.T. and J.C. Mitchell (eds.). 2020. Snakes of Arizona. ECO Wear and Publishing, Rodeo, New Mexico, 860 pp.
  7. Klauber, L. M. 1936. <i>Crotalus mitchellii</i>, the speckled rattlesnake. Transactions of the San Diego Society of Natural History 8:149–184
  8. Knight, A., D. Styer, S. Pelikan, J. A. Campbell, L. D. Densmore III, and D. P. Mindell. 1993. Choosing among hypotheses of rattlesnake phylogeny: a best-fit rate test for DNA sequence data. Systematic Biology 42(3):356-367.
  9. McCranie, J. R. 1988. Description of the hemipenis of <i>Sistrurus ravus </i>(Serpentes: Viperidae). Herpetologica 44:123-126.
  10. Meik, J. M. and R.D. Babb. 2020. <i>Crotalus pyrrhus</i>, Southwestern Speckled Rattlesnake. Pages 588-599 in A.T. Holycross and J.C. Mitchell (eds.). 2020. Snakes of Arizona. ECO Wear and Publishing, Rodeo, New Mexico.
  11. Meik J. M., J. W. Streicher, A. M. Lawing, O. Flores-Villela, and M. K. Fujita. 2015. Limitations of climatic data for inferring species boundaries: insights from speckled rattlesnakes. PLoS ONE 10(6): e0131435. doi:10.1371/journal.pone.0131435
  12. Murphy, R. W., J. Fu, and A. Lathrop. 2002. Phylogeny of the rattlesnakes (<i>Crotalus </i>and <i>Sistrurus</i>) inferred from sequences of five mitochondrial DNA genes. Pages 69-92 in G. W. Schuett, M. Hoggren, M. E. Douglas, and H. W. Greene, editors. Biology of the Vipers. Eagle Mountain Publishing, Eagle Mountain, Utah.
  13. Parkinson, C. L. 1999. Molecular systematics and biogeographical history of pitvipers as determined by mitochondrial ribosomal DNA sequences. Copeia 1999:576-586.
  14. Pyron, R. A., F. T. Burbrink, and J. J. Wiens. 2013. A phylogeny and revised classification of Squamata, including 4161 species of lizards and snakes. BMC Evolutionary Biology 29:131.
  15. Stille, B. 1987. Dorsal scale microdermatoglyphics and rattlesnake (<i>Crotalus </i>and <i>Sistrurus</i>) phylogeny (Reptilia: Viperidae: Crotalinae). Herpetologica:98-104.