Crotalus willardi

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Crotalus willardi

Least Concern  (IUCN 3.1)[1]
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Suborder: Serpentes
Family: Viperidae
Genus: Crotalus
Species:
C. willardi
Binomial name
Crotalus willardi
Meek, 1905
Synonyms[2][3]
  • Crotalus willardi
    Meek, 1905
  • Crotalus willardi willardi
    — Klauber, 1949
Common names: ridge-nosed rattlesnake, Willard's rattlesnake, Willard's rattler[4]

Crotalus willardi is a

pit viper species found in the southwestern United States and Mexico. This snake is found mainly in the "sky island" region.[5] The IUCN reports this snake's conservation status as being of Least Concern.[1] It is the official state reptile of Arizona.[6]

Etymology

The specific name, willardi, is in honor of its discoverer, "Professor" Frank Cottle Willard, a businessman from Tombstone, Arizona.[7][8]

Taxonomy

Originally described in 1905, Crotalus willardi is the most recent rattlesnake species to be discovered in the United States. Five

state reptile of Arizona
.

Description

Crotalus willardi is a rather small rattlesnake with all subspecies measuring one to two feet (30–60 cm) in length. Color patterns are generally a dark brown base with pale or white horizontal striping, but vary slightly among subspecies. It has the odd distinction of being named last as a new species, as there is no mistaking the clear cut ridge that follows the countour of its snout, a ridge formed by turning up the scales on the end of its nose. [10]

Habitat

C. willardi is rarely found outside habitats at high elevation. Wooded mountain ranges, primarily in the southwest, are where this reclusive species is found. Each subspecies’ range is limited to select mountain ranges, making human encounters rare events.

Conservation status

The species C. willardi is classified as Least Concern on the

IUCN Red List of Threatened Species (v3.1, 2001).[1] Species are listed as such due to their wide distribution, presumed large population, or because they are unlikely to be declining fast enough to qualify for listing in a more threatened category. The population trend was stable when assessed in 2007.[11]

Although four of the five

US Fish and Wildlife Service. Remaining populations are scattered throughout New Mexico, Arizona and the northern part of Mexico. Habitat destruction
is the cause of declining numbers, but critical habitat designations (recovery measures) have been proposed.

Behavior and diet

Rattlesnakes are primarily ambush hunters; they coil and lie waiting for prey to approach within striking distance. The diet of C. willardi includes small

centipedes (Scolopendra spp.) and lizards, whereas adults feed primarily on mammals and birds.[12]

Reproduction

Like other rattlesnakes, C. willardi is

viviparous animals, the young still develop within an egg inside the female snake until their time of birth. Copulation occurs from late summer to early fall, and gestation lasts about four to five months. Females give birth to two to 9 (average five) young in late July or August. Both sexes appear to reach reproductive maturity around 400 mm (16 in) in body (snout to vent) length. Although captive snakes have reproduced annually, wild females probably reproduce every second or third year.[13]

Venom

Due to the generally small size of C. willardi, venom discharge yields are low; thus, the largely hemotoxic venom is not as life-threatening as that of other rattlesnakes. No documented deaths have been caused by ridge-nosed rattlesnakes, but pain and discomfort can still result from a rare bite.

Subspecies

Subspecies[9] Taxon author[9] Common name[14] Geographic range[15][16]
C. w. amabilis Anderson, 1962 Del Nido ridge-nosed rattlesnake Mexico in north-central Chihuahua
C. w. meridionalis Klauber, 1949 Southern ridge-nosed rattlesnake Mexico in southern Durango and southwestern Zacatecas
C. w. obscurus Harris & Simmons, 1974 New Mexico ridge-nosed rattlesnake The US in extreme southeastern Arizona and extreme southwestern New Mexico, Mexico in extreme northwestern Chihuahua and extreme northeastern Sonora
C. w. silus Klauber, 1949 Chihuahuan ridge-nosed rattlesnake Western Chihuahua and eastern Sonora
C. w. willardi Meek, 1905 Arizona ridge-nosed rattlesnake Southeastern Arizona, and northern Sonora

References

  1. ^
    doi:10.2305/IUCN.UK.2007.RLTS.T62253A12584209.en
    . Retrieved 19 November 2021.
  2. ISBN 1-893777-01-4
    (volume).
  3. ^ "Crotalus willardi ". The Reptile Database. www.reptile-database.org.
  4. ISBN 0-8014-0463-0
    ). (Crotalus willardi, pp. 1034-1037, Figures 294-295 + Map 67 on p. 951).
  5. ^ Brennan, Thomas (2008). "RIDGE-NOSED RATTLESNAKE Crotalus willardi". Retrieved 16 May 2019. http://www.reptilesofaz.org/Snakes-Subpages/h-c-willardi.html Archived 2016-08-11 at the Wayback Machine
  6. ^ Arizona Rattlesnakes: Rattlesnake Facts, Arizona Game and Fish Department, retrieved 2019-05-16
  7. ^ Beltz, Ellin (2006). Biographies of People Honored in the Names of the Reptiles and Amphibians of North America
  8. ISBN 978-1-4214-0135-5
    . (Crotalus willardi, p. 286).
  9. ^ a b c "Crotalus willardi ". Integrated Taxonomic Information System. Retrieved 16 May 2007.
  10. ISBN 978-0-394-48882-0
    .
  11. ^ 2001 Categories & Criteria (version 3.1) at the IUCN Red List. Accessed 13 September 2007.
  12. ^ Holycross et al., 2002.
  13. ^ Holycross & Goldberg, 2001.
  14. ISBN 0-8069-6460-X
    .
  15. ISBN 0-8014-4141-2
    .
  16. ISBN 0-520-21056-5
    ).

Further reading

External links

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