Elongate mud meadows springsnail (Pyrgulopsis notidicola)

http://ecos.fws.gov/docs/candforms_pdf/r8/G0C6_I01.pdf

 2 
BIOLOGICAL INFORMATION 
 
Pyrgulopsis notidicola is a member of the family Hydrobiidae, which consists of approximately 
about100 species of small freshwater gastropods found in the western United States.  Although 
few studies have been conducted on species within the genus Pyrgulopsis (springsnails) in the 
Great Basin, general knowledge about their natural history exists.   Pyrgulopsis are small 
(usually less than 5 millimeters [0.2 inches (in.)] high, are tightly linked with their aquatic 
habitat, and often are endemic to single bodies of water (particularly springs), or local drainage 
features (Hershler 1998).  Pyrgulopsis are widespread within the Great Basin where they occur 
in a variety of relatively small, usually fishless, spring-fed water bodies.  This genus also 
historically occurred in a few Great Basin lakes; none have been found in rivers.  Pyrgulopsis 
springsnails only occupy permanent springs because they cannot survive outside an aquatic 
environment.  Therefore, extant populations are in aquatic habitats that have persisted for long 
periods of geological time (Taylor 1985).  It is uncommon for a spring to be occupied by more 
than one species of springsnail.  Pyrgulopsis often decline dramatically in density downstream 
from spring sources, presumably reflecting their requirement for the well-known stable 
temperature, chemistry, and flow regime characterized by headsprings (Deacon and Minkley 
1974).  They feed on algae gleaned from the substrate and aquatic vegetation, and they occupy 
habitats with good water quality.  Although they may occupy a number of different substrates, 
most species prefer either sand, gravel, or cobble (Deacon and Minkley 1974).  There have been 
no studies on the life history of the Great Basin species. 
 
Pyrgulopsis notidicola was described by Hershler (1998) and is distinguished from three other 
species in the Soldier Meadow area by its more elongate shell with short spire; larger and more 
disjunct aperature; well-developed columellar shelf; smaller, globose bursa copulatrix; penis 
with larger terminal gland; and very weak ventral gland. 
 
Pyrgulopsis notidicola is endemic to Soldier Meadow, which is located at the northern extreme 
of the western arm of the Black Rock Desert in the transition zone between the Basin and Range 
Physiographic Province and the Columbia Plateau Province, Humboldt County, Nevada.  This 
region is characterized by cold, dry winters influenced primarily by cool, polar air masses, and 
by hot, dry summers influenced primarily by warm, tropical air masses (Nachlinger 1991).  
Soldier Meadow lies between the Calico Mountains to the west and the Black Rock Range to the 
east, and encompasses a province of approximately 50 thermal, connected and isolated springs in 
an alluvial basin at the northwestern terminus of the Black Rock Desert about 121 kilometers 
(km) [75 miles (mi)] north of Gerlach, Nevada and 16 km (10 mi) south of the Summit Lake 
Paiute Indian Reservation. The vegetation is broadly classified into four wetland communities 
and three upland communities, one of which is considered transitional.  The wetland 
communities support a tremendous diversity of plants, with over 60 different species identified 
in the marshes, seeps, and meadows.  Thermal springs occur in the area at elevations ranging 
from 1,320 and 1,393 m (4,330 and 4,570 ft) (Nachlinger 1991).  Some of the springs provide the 
only known habitat for the desert dace (Eremichthys acros), a federally-listed species endemic to 
approximately 20 springs in Soldier Meadow (Knight 1990). 






http://frwebgate5.access.gpo.gov/cgi-bin/waisgate.cgi?WAISdocID=681311318978+4+0+0&WAISaction=retrieve


[Federal Register: May 11, 2005 (Volume 70, Number 90)]
[Proposed Rules]               
[Page 24869-24934]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr11my05-19]                         

Page 24869

DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

 Endangered and Threatened Wildlife and Plants; Review of Native 
Species That Are Candidates or Proposed for Listing as Endangered or 
Threatened; Annual Notice of Findings on Resubmitted Petitions; Annual 
Description of Progress on Listing Actions

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Notice of review.

...


    Elongate mud meadows springsnail (Pyrgulopsis notidicola)--The 
following summary is based on information contained in our files. No 
new information was provided in the petition received on May 11, 2004. 
Pyrgulopsis notidicola is endemic to Soldier Meadow, which is located 
at the northern extreme of the western arm of the Black Rock Desert, in 
the transition zone between the Basin and Range Physiographic Province 
and the Columbia Plateau Province, Humboldt County, Nevada. The type 
locality, and the only known location of the species, occurs in a 
stretch of thermal (between 45[deg] Celsius (C) (113[deg] Fahrenheit 
(F)) and 32[deg] C (90[deg] F)) aquatic habitat that is approximately 
300 m (984 ft) long and 2 m (6.7 ft) wide. Pyrgulopsis notidicola 
occurs only in shallow, flowing water on gravel substrate. The species 
does not occur in deep water (i.e., impoundments) where water velocity 
is low, gravel substrate is absent, and sediment levels are high. The 
present or threatened destruction, modification, or curtailment of its 
habitat or range by recreational bathers in the thermal waters is the 
greatest threat to the species. The small size of their habitat and 
their limited range makes them highly susceptible to any factors that 
negatively impact their habitat. Regulatory mechanisms are beginning to 
be put in place, but few actions have been implemented to date. Based 
on imminent threats of high magnitude, we retain a listing priority 
number of 2 for this species.