Ashmunella rhyssa

(Dall, 1897)

Sierra Blanca Woodlandsnail

G3Vulnerable Found in 1 roadless area NatureServe Explorer →
G3VulnerableGlobal Rank
UnknownThreat Impact
Identity
Unique IDELEMENT_GLOBAL.2.118081
Element CodeIMGAS92290
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryInvertebrate Animal
Endemicendemic to a single state or province
KingdomAnimalia
PhylumMollusca
ClassGastropoda
OrderStylommatophora
FamilyPolygyridae
GenusAshmunella
Concept Reference
Turgeon, D. D., J. F. Quinn, Jr., A. E. Bogan, E. V. Coan, F. G. Hochberg, W. G. Lyons, P. M. Mikkelsen, R. J. Neves, C. F. E. Roper, G. Rosenberg, B. Roth, A. Scheltema, F. G. Thompson, M. Vecchione, and J. D. Williams. 1998. Common and scientific names of aquatic invertebrates from the United States and Canada: Mollusks. 2nd Edition. American Fisheries Society Special Publication 26, Bethesda, Maryland. 526 pp.
Taxonomic Comments
Several species and subspecies of recent and fossil Ashmunella have been described from the Sierra Blanca Mountains. Pilsbry (1940) recognized three species and a number of subspecies. Stern (1973) reduced the Sierra Blanca Mountains Ashmunella species recognized by Pilsbry (1940) to one species, A. rhyssa, with two subspecies, A. rhyssa rhyssa and A. rhyssa altissima. Several presumed variants of A. rhyssa occur in calcareous Quaternary sediments of Sacramento Mountains but none has been given taxonomic recognition but some from the Sacramento Mountains Pleistocene have been named by Metcalf (Metcalf and Smartt 1997).
Conservation Status
Rank MethodLegacy Rank calculation - Biotics v1
Review Date2019-12-16
Change Date2019-12-16
Edition Date2019-12-16
Edition AuthorsCordeiro, J. (2019)
Threat ImpactUnknown
Range Extent1000-5000 square km (about 400-2000 square miles)
Number of Occurrences21 - 80
Rank Reasons
This high altitude New Mexico endemic that is distributed moderately 1000-5000 sq km but only at high elevation. It is divided into two subspecies, one of which is much more narrowly distributed amidst two peaks at a much higher elevation that the other and is much more rare. Current threats and trends are not known but historical subfossil information indicates the species, as a whole, had a much wider distribution at lower elevation than it does now.
Range Extent Comments
This species is confined to the Sierra Blanca - Sacramento Mountains complex of New Mexico. Stern (1973) interpreted the nominal subspecies (A. rhyssa rhyssa) as occurring throughout the Sacramento Mountains and northward to the lower south, east, and west slopes of Sierra Blanca Peak. On Sierra Blanca, at 8000-9000 feet, Stern detected intergradation between the two subspecies (A. rhyssa altissima on the uppermost slopes and the summit; A. rhyssa rhyssa on the northern slopes of Sierra Blanca and northward in the Sierra Mountains to the Nogal Peak area) (Stern 1973, Metcalf and Smartt 1997). A. rhyssa altimissa occurs on the Sierra Blanca and Nogel Peak area as well as one occurrence in the Tularosa Valley between (McCort and Metcalf, 1986).
Occurrences Comments
More than 20 localities of A. rhyssa rhyssa are reported in Metcalf and Smartt (1997). Subspeces A. rhyssa altissima has far fewer (<5). In a study of terrestrial gastropods of central and north-central New Mexico (1952-54) it was found that the greatest number of species was fund in the 8100 to 9000-foot and 9100 to 10,000-foot increments, with a slightly smaller number in the 7100 to 8000-foot increment. The numbers of different species found at various elevations decline strongly above 10,000 feet and are drastically reduced below 7500 feet (Hoff, 1962).
Threat Impact Comments
Threats have not been assessed for this species. Generally speaking, land snails are one of the most threatened and understudied organisms in North America (Lydeard et al., 2004). Humans have proven to be excellent dispersers for low mobility organisms like land snails (Cowie and Robinson, 2003). Over the decades, snails have been deliberately and accidently introduced through numerous pathways. In one of the most comprehensive studies on how nonindigenous land snails and slugs are being introduced, Cowie and Robinson (2003), outline the known pathways. Snails and other organisms are continuously losing habitat to urbanization, leading to major declines in urban biodiversity (Czech et al., 2000; McKinney 2002). With high altitude species, climate change can cause significant negative effects because as temperature warms, habitat disappears possibly to the point of extinction.
Ecology & Habitat

Habitat

Ashmunella rhyssa rhyssa is widespread in the Sacramento Mountains, both areally and altitudinally. It is especially common along canyons, occurring as low as 5,750-ft altitude, being found in limestone talus at lower elevations. At higher elevations, in the Canadian Life Zone, the species may be found throughout the forests. In general, A. r. rhyssa is associated with the limestone terrane of the Sacramento Mountains. A. rhyssa rhyssa, although restrictive in habitat mainly to talus, is especially common along the canyon, occurring as low as 5750 ft, being found in limestone talus at lower elevations (Metcalf and Smartt, 1997). A. r. rhyssa is also found along the lower part of Three Rivers Canyon in an area of igneous rock. (Metcalf and Smartt, 1997). At higher elevations, in the Canadian Life Zone, it may be found throughout the forests and likely has the highest population density of any Ashmunella in New Mexico in the high forests of the Sacramento Mountains (Metcalf and Smartt, 1997). A. rhyssa altissima associated with igneous bedrock of Sierra Blanca Mountains from northern Sierra Blanca to Nogal Peak area at much higher altitude than A. rhyssa rhyssa. It tolerates the highest summit of Sierra Blanca and Nogal Peaks; the former being almost 6500 ft higher than the lowest elevations inhabited by the species (snails find shelter in rock talus). Numerous collections have been made along canyons in Sierra Blanca Mountains, where colonies are often found along streams under willow and other small trees (Metcalf and Smartt, 1997). At these very high altitudes, above tree line, snails find shelter in rock talus, much as their relatives do at the lowest elevations. Specimens have been found in the presence of aspen litter - one in the midst of an aspen grove, at about 10,000 feet elevation (Hoff, 1962).

Reproduction

Reproduction and life history information are largely unknown.
Terrestrial Habitats
Forest - HardwoodAlpineBare rock/talus/scree
Other Nations (1)
United StatesN3
ProvinceRankNative
New MexicoS3Yes
Threat Assessments
ThreatScopeSeverityTiming
11 - Climate change & severe weatherLarge (31-70%)Extreme - moderateLow (long-term)

Roadless Areas (1)
New Mexico (1)
AreaForestAcres
West Face Sacramento MountainsLincoln National Forest41,176
References (4)
  1. Hoff, C.C. 1962. Some terrestrial Gastropoda from New Mexico. Southwestern Naturalis 7:51-63.
  2. Metcalf, A.L. and R.A. Smartt. 1997. Land snails of New Mexico. Bulletin of the New Mexico Museum of Natural History and Science, 10: 1-145.
  3. Pilsbry, H.A. 1940. Land Mollusca of North America (north of Mexico). Volume 1, Part 2. Monograph of the Academy of Natural Sciences of Philadelphia, 1(2): 574-994.
  4. Turgeon, D. D., J. F. Quinn, Jr., A. E. Bogan, E. V. Coan, F. G. Hochberg, W. G. Lyons, P. M. Mikkelsen, R. J. Neves, C. F. E. Roper, G. Rosenberg, B. Roth, A. Scheltema, F. G. Thompson, M. Vecchione, and J. D. Williams. 1998. Common and scientific names of aquatic invertebrates from the United States and Canada: Mollusks. 2nd Edition. American Fisheries Society Special Publication 26, Bethesda, Maryland. 526 pp.