Assiminea pecos

Pecos Assiminea

FWS Focus

Overview

Characteristics
Overview

Pecos assiminea (Assiminea pecos) is a very small, federally endangered snail found in a few locations of the Pecos River Basin in New Mexico and Texas. Snails in the Assiminea genus are primarily marine and usually associated with the sea, Pecos assiminea is found the furthest inland of all these species. They live in association with vegetation and under plant litter, in saturated soils near flowing springs and seeps. Significant threats to the species and its habitat are primarily correlated to deterioration of water quality and quantity, which is exacerbated by drought, as well the as impacts from intense wildfire and invasive plants and animals.     

 

 

Taylor, D.W. 1987. Fresh-water mollusks from New Mexico and vicinity. New Mexico Bureau of Mines and Mineral Resources Bulletin 116.

U.S. Fish and Wildlife Service. 2005. Endangered and Threatened wildlife and plants: Listing Roswell springsnail, Koster’s springsnail, Noel’s amphipod and Pecos assiminea as endangered with critical habitat: Final Rule. Federal Register 70:46,304–46,333.

U.S. Fish and Wildlife Service. 2019. Recovery Plan for Four Invertebrate Species of the Pecos River Valley: Noel’s amphipod (Gammarus desperatus), Koster’s springsnail (Juturnia kosteri), Roswell springsnail (Pyrgulopsis roswellensis), and Pecos assiminea (Assiminea pecos). New Mexico Ecological Services Field Office, Albuquerque.

Scientific Name

Assiminea pecos
Common Name
Pecos Assiminea
Pecos assiminea snail
FWS Category
Snails
Kingdom

Location in Taxonomic Tree

Genus
Species

Identification Numbers

TSN:

Characteristics

Characteristic category

Habitat

Characteristics
Habitat

Pecos assiminea is closely associated with permanent spring run wetland habitats, where they live in saturated mud with plant communities that are dominated by species like saltgrass (Distichlis spicata), chairmaker’s bulrush (Schoenoplectus americanus), common reed (Phragmites australis), spike rushes (Eleocharis spp.) and rushes (Juncus spp.). They are typically near the surface of the soil beneath mats of vegetation and plant litter, and may also rarely occur in the water of aquatic habitats. A balanced amount of vegetation litter is an important habitat component that provides food, shade, cover and maintains microhabitat temperature and moisture.

 

Lang, B.K. 2002. Status of aquatic mollusks of New Mexico. Report to U.S. Fish and Wildlife Service, Albuquerque, New Mexico. New Mexico Department of Fish and Game, Santa Fe, New Mexico.

New Mexico Department of Game and Fish. 1998. Macroinvertebrate population monitoring at Bitter Lake National Wildlife Refuge, June 1995 to June 1998. Appendix B. Status of aquatic mollusks of New Mexico. Report to U. S. Fish and Wildlife Service, Albuquerque, New Mexico.

Roesler, E.L. 2016. Development of habitat use data, detection, and survey methods for the endangered gastropod, Pecos assiminea (Assiminea pecos), at Bitter Lake National Wildlife Refuge. Master’s Thesis. Texas Tech University, Lubbock, Texas.

Taylor, D.W. 1987. Fresh-water mollusks from New Mexico and vicinity. New Mexico Bureau of Mines and Mineral Resources Bulletin 116.

U.S. Fish and Wildlife Service. 2005. Endangered and Threatened wildlife and plants: Listing Roswell springsnail, Koster’s springsnail, Noel’s amphipod and Pecos assiminea as endangered with critical habitat: Final Rule. Federal Register 70:46,304–46,333.

U.S. Fish and Wildlife Service. 2019. Recovery Plan for Four Invertebrate Species of the Pecos River Valley: Noel’s amphipod (Gammarus desperatus), Koster’s springsnail (Juturnia kosteri), Roswell springsnail (Pyrgulopsis roswellensis), and Pecos assiminea (Assiminea pecos). New Mexico Ecological Services Field Office, Albuquerque.

Desert

Area of land that receives no more than 25 centimeters (10 inches) of precipitation a year.

Grassland

Ecosystem with large, flat areas of grasses.

Wetland
River or Stream
Cave or Karst
Rural
Urban
Lake
Characteristic category

Food

Characteristics
Food

Pecos assiminea have a radula, an organ of tiny teeth, that they use to scrape food off of surfaces and into their mouth. They likely forage on the bacteria, detritus, fungi and algae found on live and dead vegetation and coarse organic matter. They may also incidentally consume small invertebrates as they feed.  

Barnes, R.D. 1980. Invertebrate zoology, 4th edition. Saunders College, Philadelphia, Pennsylvania.

New Mexico Department of Game and Fish (NMDGF). 1988. Handbook of species endangered in New Mexico. New Mexico Department of Game and Fish, Santa Fe, New Mexico.

U.S. Fish and Wildlife Service. 2005. Endangered and Threatened wildlife and plants: Listing Roswell springsnail, Koster’s springsnail, Noel’s amphipod and Pecos assiminea as endangered with critical habitat: Final Rule. Federal Register 70:46,304–46,333.

U.S. Fish and Wildlife Service. 2019. Recovery Plan for Four Invertebrate Species of the Pecos River Valley: Noel’s amphipod (Gammarus desperatus), Koster’s springsnail (Juturnia kosteri), Roswell springsnail (Pyrgulopsis roswellensis), and Pecos assiminea (Assiminea pecos). New Mexico Ecological Services Field Office, Albuquerque.

Characteristic category

Lifecycle

Characteristics
Reproduction

Breeding habitat specifics or associated behavior has not been studied for this species. 

Taylor, D.W. 1987. Fresh-water mollusks from New Mexico and vicinity. New Mexico Bureau of Mines and Mineral Resources Bulletin 116.

U.S. Fish and Wildlife Service. 2019. Recovery Plan for Four Invertebrate Species of the Pecos River Valley: Noel’s amphipod (Gammarus desperatus), Koster’s springsnail (Juturnia kosteri), Roswell springsnail (Pyrgulopsis roswellensis), and Pecos assiminea (Assiminea pecos). New Mexico Ecological Services Field Office, Albuquerque.

Lifecycle

Individual Pecos assiminea snails are strictly male or female. Fertilization is internal, and females likely deposit eggs in gelatinous masses in their habitat where they develop into larvae. Little is known about specific development details in this species, other gastropods may reach sexual maturity in as few as six months. The seasonality, frequency of breeding, fecundity, or other aspects of reproduction are also unknown. Fluctuating surface water levels and winter freezing of inundated areas appear to be limiting factors influencing population size and individual mortality. 

Barnes, R.D. 1980. Invertebrate zoology, 4th edition. Saunders College, Philadelphia, Pennsylvania.

New Mexico Department of Game and Fish. 2010. Macroinvertebrates of Bitter Lake National Wildlife Refuge. Report to U.S. Fish and Wildlife Service. New Mexico. Department of Fish and Game, Santa Fe, New Mexico

U.S. Fish and Wildlife Service. 2019. Recovery Plan for Four Invertebrate Species of the Pecos River Valley: Noel’s amphipod (Gammarus desperatus), Koster’s springsnail (Juturnia kosteri), Roswell springsnail (Pyrgulopsis roswellensis), and Pecos assiminea (Assiminea pecos). New Mexico Ecological Services Field Office, Albuquerque.

Lifespan

The lifespan of Pecos assiminea has not been recorded. 

Characteristic category

Behavior

Characteristics
Behavior

Pecos assiminea respire by breathing air directly. They commonly maintain an air bubble in their mantle cavity, and have gills that are vestigial, or remnant, and not likely used for primary respiration. Pecos assiminea are presumably nocturnal and most active at night, which is similar to their neighboring gastropods. 

New Mexico Department of Game and Fish. 1998. Macroinvertebrate population monitoring at Bitter Lake National Wildlife Refuge, June 1995 to June 1998. Appendix B. Status of aquatic mollusks of New Mexico. Report to U. S. Fish and Wildlife Service, Albuquerque, New Mexico.

Taylor, D.W. 1987. Fresh-water mollusks from New Mexico and vicinity. New Mexico Bureau of Mines and Mineral Resources Bulletin 116.

U.S. Fish and Wildlife Service. 2005. Endangered and Threatened wildlife and plants: Listing Roswell springsnail, Koster’s springsnail, Noel’s amphipod and Pecos assiminea as endangered with critical habitat: Final Rule. Federal Register 70:46,304–46,333.

U.S. Fish and Wildlife Service. 2019. Recovery Plan for Four Invertebrate Species of the Pecos River Valley: Noel’s amphipod (Gammarus desperatus), Koster’s springsnail (Juturnia kosteri), Roswell springsnail (Pyrgulopsis roswellensis), and Pecos assiminea (Assiminea pecos). New Mexico Ecological Services Field Office, Albuquerque.

Characteristic category

Physical Characteristics

Characteristics
Physical Characteristics

Pecos assiminea (Assiminea pecos) is a very small golden snail found in a few locations of the Pecos River Basin in New Mexico and Texas. Snails in the Assiminea genus are primarily marine and usually associated with the sea, Pecos assiminea is found the furthest inland of all these species.   

 

 

Size & Shape

Pecos assiminea range from 1.36 to 2.16 millimeters (0.05 to 0.08 inches) in shell length, with females being larger than males. Their shell has a broad, oval opening and is regularly conical, with up to 4.5 strongly incised whorls. The genus Assiminea does not have tentacles and their eyes are in the tips of short stalks.

Taylor, D.W. 1987. Fresh-water mollusks from New Mexico and vicinity. New Mexico Bureau of Mines and Mineral Resources Bulletin 116.

U.S. Fish and Wildlife Service. 2005. Endangered and Threatened wildlife and plants: Listing Roswell springsnail, Koster’s springsnail, Noel’s amphipod and Pecos assiminea as endangered with critical habitat: Final Rule. Federal Register 70:46,304–46,333.

U.S. Fish and Wildlife Service. 2019. Recovery Plan for Four Invertebrate Species of the Pecos River Valley: Noel’s amphipod (Gammarus desperatus), Koster’s springsnail (Juturnia kosteri), Roswell springsnail (Pyrgulopsis roswellensis), and Pecos assiminea (Assiminea pecos). New Mexico Ecological Services Field Office, Albuquerque.

 

 

Color & Pattern

The shell of Pecos assiminea is chestnut color and nearly translucent.  

Taylor, D.W. 1987. Fresh-water mollusks from New Mexico and vicinity. New Mexico Bureau of Mines and Mineral Resources Bulletin 116.

U.S. Fish and Wildlife Service. 2005. Endangered and Threatened wildlife and plants: Listing Roswell springsnail, Koster’s springsnail, Noel’s amphipod and Pecos assiminea as endangered with critical habitat: Final Rule. Federal Register 70:46,304–46,333.

 

Weight

No recorded weight measurements for Pecos assiminea are available at this time.

Sound

Sounds have not been identified or recorded for Pecos assiminea. 

Characteristic category

Similar Species

Characteristics
Similar Species

A population of snails along the Río Monclova in Coahuila, Mexico, were initially reported to be Pecos assiminea. They have since been described as a separate species, Assiminea cienegensis, which are genetically distinct and have a smaller and broader shell.  

Hershler, R., H.P. Liu, and B.K. Lang. 2007. Genetic and morphologic variation of the Pecos assiminea, an endangered mollusk of the Rio Grande region, United States and Mexico (Caenogastropoda: Rissooidea: Assimineidae). Hydrobiologia 579:317-335.

Taylor, D.W. 1987. Fresh-water mollusks from New Mexico and vicinity. New Mexico Bureau of Mines and Mineral Resources Bulletin 116.

U.S. Fish and Wildlife Service. 2005. Endangered and Threatened wildlife and plants: Listing Roswell springsnail, Koster’s springsnail, Noel’s amphipod and Pecos assiminea as endangered with critical habitat: Final Rule. Federal Register 70:46,304–46,333.

U.S. Fish and Wildlife Service. 2019. Recovery Plan for Four Invertebrate Species of the Pecos River Valley: Noel’s amphipod (Gammarus desperatus), Koster’s springsnail (Juturnia kosteri), Roswell springsnail (Pyrgulopsis roswellensis), and Pecos assiminea (Assiminea pecos). New Mexico Ecological Services Field Office, Albuquerque.

Geography

Characteristics
Range

When Pecos assiminea was described in 1987, snails were found at three isolated localities: inChaves County on BLNWR in New Mexico; Diamond Y Spring in Pecos County, Texas; and inthe Bolsón de Cuatro Ciénegas, Coahuila, Mexico (Taylor 1987: 9). Taylor (1987: 8-9) reportedextirpation of two locations in Chaves County: one at North Spring at the Roswell Country Cluband the other at the type locality (Unit 7 spring ditch) on BLNWR (Figures 5 and 12). Taylor(1987: 9) reported possible fossil Pecos assiminea from along the Pecos River near Grandfalls,Texas, and the Río Monclova, Coahuila, México. Pecos assiminea occurs at Diamond Y Spring Preserve (Diamond Y Spring source pool, Monsanto Spring, Euphrasia Spring, and John’s Pool) owned by The Nature Conservancy, inPecos County, Texas (Figure 6; NMDGF 2000: A3) and at East Sandia Spring in ReevesCounty, Texas, on private lands under stewardship of The Nature Conservancy (Figure 7;NMDGF 2000: A3). The species also persists at BLNWR. On BLNWR, Pecos assiminea iscurrently found in the upper reaches of Bitter Creek near Dragonfly Spring, the lower end ofBitter Creek, the lower reaches of the Sago Spring Complex near Sinkhole No. 32 (and 31), inthe Unit 7 spring ditch, in the Snail Unit, and at a spring in the extreme southwestern corner ofUnit 15 (Figures 8 12, and 12a; Lang 2002: A5; Roesler 2016: 58). The species was not found atNorth Spring on the Roswell Country Club during a survey in August 2004 (Figure 5; NMDGF2005: 1). Pecos assiminea was found (single recent empty shell) in Hunter Marsh in 2009, butsubsequent intensive sampling in 2010 did not further identify any individuals (Figure 10;NMDGF 2010: 9).

Taylor, D.W. 1987. Fresh-water mollusks from New Mexico and vicinity. New Mexico Bureau of Mines and Mineral Resources Bulletin 116.

U.S. Fish and Wildlife Service. 2005. Endangered and Threatened wildlife and plants: Listing Roswell springsnail, Koster’s springsnail, Noel’s amphipod and Pecos assiminea as endangered with critical habitat: Final Rule. Federal Register 70:46,304–46,333.

U.S. Fish and Wildlife Service. 2011. Endangered and Threatened wildlife and plants: Designation of critical habitat for Roswell springsnail, Koster’s springsnail, Noel’s amphipod and Pecos assiminea: Final Rule. Federal Register 76:33,036–33,064.

U.S. Fish and Wildlife Service. 2019. Recovery Plan for Four Invertebrate Species of the Pecos River Valley: Noel’s amphipod (Gammarus desperatus), Koster’s springsnail (Juturnia kosteri), Roswell springsnail (Pyrgulopsis roswellensis), and Pecos assiminea (Assiminea pecos). New Mexico Ecological Services Field Office, Albuquerque.

Import/Export

This species and its parts are not available to import or export.

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