Gammarus desperatus

Noel's Amphipod

FWS Focus

Overview

Characteristics
Overview

Noel's amphipod (Gammarus desperatus) is a federally endangered invertebrate constrained to localized karst features with reliable sources of clean groundwater. Inland amphipods are sometimes referred to as freshwater shrimp. This rare species of crustacean has no carapace, respires primarily through gills and has only been found within a few spring systems in the Roswell Basin desert-grassland of southeastern New Mexico, including Bitter Lake National Wildlife Refuge. A challenge facing this species is their need for consistently flowing water of a certain quality and the impacts of groundwater pumping and contaminants in their surrounding aquifer, particularly during times of drought. 

Scientific Name

Gammarus desperatus
Common Name
Noel's amphipod
Bitter Lakes amphipod
FWS Category
Crustaceans
Kingdom

Location in Taxonomic Tree

Identification Numbers

TSN:

Characteristics

Characteristic category

Physical Characteristics

Characteristics
Physical Characteristics

Noel's amphipod (Gammarus desperatus) is a federally endangered invertebrate species constrained to localized karst features with reliable sources of clean groundwater. It is a crustacean that depends on gills for respiration,  

  • Indicators of whether the species has an FWS focus, has (or had) regulations applied to it (including proposed statuses), and whether the species can be found on a refuge (as sourced from the IRIS database of occurrence data from Refuges).
  • Overview providing a high-level description of the taxon and the Services involvement with it as applicable.
  • FWS Categories for the species such as fur-bearer, pollinator, etc.
  • The kingdom the taxon belongs to and where it is located in the taxonomic tree including its rank.
  • Regulatory status changes that have been applied to the species.
  • Identification numbers used as keys to the profile record.
Color & Pattern

Noel’s amphipods are brown-green in color and flanked with red bands along their thoracic and abdominal segments, often with a red dorsal stripe.

Weight

No recorded weight measurements for Noel's amphipod are available at this time. 

Sound

Noel's amphipod sounds have not been identified or recorded. 

Size & Shape

Noel's amphipods have the shape of tiny shrimp. They are laterally-flattened and covered in bristles, with long, kidney-shaped eyes. Noel’s amphipod males are generally larger than females.

MeasurementsMales typically range from 9.45 to 14.8 millimeters (0.37 to 0.58 inches) in length.Females typically range from 8.5 to 12.6 millimeters (0.34 to 0.50 inches) in length. 

Noel’s amphipods that measure smaller than 8.5 millimeters in length have been observed with regularity during monitoring efforts at Bitter Lake National Wildlife Refuge.

Characteristic category

Life Cycle

Characteristics
Lifespan

Most amphipods complete their life cycle in one year or less.

Reproduction

The breeding season for most amphipods is dependent on water temperature and commonly occurs from February through October. Typically one brood is produced, however some species have been recorded having produced a series of broods over their breeding season.

Lifecycle

Gammarus males and females pair for one to seven days, feeding and swimming together prior to copulation. Copulation and sperm transfer lasts less than one minute. An average of 15 to 50 fertilized eggs are retained in the female’s brood pouch, also called a marsupium, where they are incubated for one to three weeks. Young remain in the marsupium for another one to eight days before being released into the aquatic environment, where they develop independently. 

Characteristic category

Similar Species

Characteristics
Similar Species

A marsh at Bitter Lake National Wildlife Refuge may contain two sympatric Gammarus species from two different Chihuahuan Desert lineages. One species is Noel's amphipod, and the second is undescribed and may be most closely related to a Gammarus lacustris type.

Characteristic category

Habitat

Characteristics
Habitat

The sinkhole and cavern karst topography that are abundant in the desert grasslands of the Roswell Artesian Basin has provided isolated limestone and gypsum springs, seeps and wetlands where Noel's amphipods have evolved. Typical aquatic habitat characteristic of gammarid amphipods are cool, shallow, well-oxygenated water that is fresh to moderately saline, permanently flowing with slow to moderate velocity, with specific acidity thresholds of pH generally between 6 and 8. Vegetation associated with Noel's amphipod habitat ranges from dense beds of emergent macrophytes, or aquatic plants, to clear, spring-fed flows with vegetated banks and submerged aquatic vegetation.

Urban
Cave or Karst
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
Rural
Characteristic category

Food

Characteristics
Food

Amphipods are omnivorous, feeding on a variety of plant material, animal matter and detritus. Beds of submerged aquatic plants are frequent shelter for Noel's amphipod, where they likely consume a diet of algae, diatoms, bacteria and fungi. Young amphipods depend on microbial foods, such as algae and bacteria associated with aquatic plants.

Characteristic category

Behavior

Characteristics
Behavior

Freshwater amphipods rely primarily on gills for respiration. They are typically nocturnal, light-sensitive and strongly oriented to their substrate. They use various appendages to clutch, push, stabilize, crawl and swim. Cannibalism is common in gammarid amphipod populations with high densities and limited food supplies.

Geography

Characteristics
Import/Export

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

Range

Noel’s amphipod has historically been known from a few locations in the Roswell Artesian Basin, including a tributary of the South Spring River near Roswell that is now dry, and a spring on the Roswell Country Club. The species has been regularly sampled on and near Bitter Lake National Wildlife Refuge in isolated and interconnected sinkhole and spring systems, and there are a total of 75.9 acres (30.7 hectares) of critical habitat designated for Noel's amphipod in three units owned by the U.S. Fish and Wildlife Service and the City of Roswell. 

Launch Interactive Map

Timeline

Explore the information available for this taxon's timeline. You can select an event on the timeline to view more information, or cycle through the content available in the carousel below.

25 Items