Stygobromus hayi - (Hubricht and Mackin, 1940)
Hay's Spring Amphipod
Taxonomic Status: Accepted
Related ITIS Name(s): Stygobromus hayi (Hubricht and Mackin, 1940) (TSN 93905)
Unique Identifier: ELEMENT_GLOBAL.2.116347
Element Code: ICMAL05630
Informal Taxonomy: Animals, Invertebrates - Crustaceans - Amphipods
 
Kingdom Phylum Class Order Family Genus
Animalia Crustacea Malacostraca Amphipoda Crangonyctidae Stygobromus
Genus Size: D - Medium to large genus (21+ species)
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Concept Reference
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Concept Reference: Fitzpatrick, J.F., Jr. 1983. How to Know the Freshwater Crustacea. Wm. C. Brown Co. Publishers. Dubuque, Iowa. 277 pp.
Concept Reference Code: B83FIT01EHUS
Name Used in Concept Reference: Stygobromus hayi
Taxonomic Comments: Previously thought to be a synonym of S. tenuis.
Conservation Status
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NatureServe Status

Global Status: G1G2
Global Status Last Reviewed: 21Aug2002
Global Status Last Changed: 21Aug2002
Rounded Global Status: G1 - Critically Imperiled
Reasons: Commonly referred to as Washington D.C.'s most famous endemic, this amphipod is only known from one population inhabiting an underground aquifer in an urban area.
Nation: United States
National Status: N1N2 (21Aug2002)

U.S. & Canada State/Province Status
Due to latency between updates made in state, provincial or other NatureServe Network databases and when they appear on NatureServe Explorer, for state or provincial information you may wish to contact the data steward in your jurisdiction to obtain the most current data. Please refer to our Distribution Data Sources to find contact information for your jurisdiction.
United States District of Columbia (S1)

Other Statuses

U.S. Endangered Species Act (USESA): LE: Listed endangered (05Feb1982)
U.S. Fish & Wildlife Service Lead Region: R5 - Northeast
IUCN Red List Category: EN - Endangered

NatureServe Global Conservation Status Factors

Range Extent: <100-250 square km (less than about 40-100 square miles)
Range Extent Comments: Collected from a single spring at the south end of National Zoological Park, Washington, D.C. and at two other locations in Rock Creek Park.

Number of Occurrences: 1 - 5
Number of Occurrences Comments: Three collection sites in close proximity to each other are known.

Population Size: Unknown
Population Size Comments: Size of population(s) is unknown. Except for the outlet, the aquifer is largely inaccessible. No more than ten individuals have been seen at any one time.

Overall Threat Impact Comments: Possible threats include groundwater contamination or flow alteration caused by further urban development.

Short-term Trend: Unknown

Other NatureServe Conservation Status Information

Distribution
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Global Range: (<100-250 square km (less than about 40-100 square miles)) Collected from a single spring at the south end of National Zoological Park, Washington, D.C. and at two other locations in Rock Creek Park.

U.S. States and Canadian Provinces

Due to latency between updates made in state, provincial or other NatureServe Network databases and when they appear on NatureServe Explorer, for state or provincial information you may wish to contact the data steward in your jurisdiction to obtain the most current data. Please refer to our Distribution Data Sources to find contact information for your jurisdiction.
Color legend for Distribution Map
Endemism: endemic to a single state or province

U.S. & Canada State/Province Distribution
United States DC

Range Map
No map available.

Ecology & Life History
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Basic Description: A small aquatic amphipod.
General Description: Albinistic; eyes lacking, body laterally compressed. Antennal flagellum 2-segmented; uropod 3 uninamous. Rostrum absent. Antenna 1-1.5 times body length; 1.25 times longer than antenna 2. Apex of male telson with 18-20 unequal spines.
Diagnostic Characteristics: Difficult to separate from sypatric S. TENUIS (has less concave palmar margin of gnathopods & proportionately shorter 2nd antennae. S. HAYI has more convex posterior margins of bases of pereiopods 5-7, more spinose uropod 1 in female, and more spinose uropod 2 in both sexes than do other, similar spp.
Reproduction Comments: Some early-March-collected females with brood plates, but ovigerous females unknown.
Ecology Comments: No data, but Holsinger (1967) believes it is unable to compete with the sympatric S. TENUIS POTOMACUS and thus, may be driven into more hypogean habitats.
Non-Migrant: N
Locally Migrant: N
Long Distance Migrant: N
Mobility and Migration Comments: Presumably benthic creeper.
Riverine Habitat(s): SPRING/SPRING BROOK
Subterranean Habitat(s): Subaquatic
Special Habitat Factors: Subterranean obligate
Habitat Comments: Inhabits a ground water outlet that feeds into a low gradient creek. Precise data lacking due to inaccessibility of habitat.
Adult Food Habits: Detritivore
Food Comments: Presumably feeds as do other amphipods.
Adult Phenology: Circadian
Phenology Comments: No meaningful data.
Length: 1 centimeters
Economic Attributes Not yet assessed
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Management Summary Not yet assessed
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Population/Occurrence Delineation Not yet assessed
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Population/Occurrence Viability
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U.S. Invasive Species Impact Rank (I-Rank) Not yet assessed
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Authors/Contributors
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NatureServe Conservation Status Factors Edition Date: 06May1998
NatureServe Conservation Status Factors Author: Morrison, M.
Element Ecology & Life History Edition Date: 17Jan1991
Element Ecology & Life History Author(s): FITZPATRICK, J. F.

Zoological data developed by NatureServe and its network of natural heritage programs (see Local Programs) and other contributors and cooperators (see Sources).

References
Help
  • Fitzpatrick, J.F., Jr. 1983. How to Know the Freshwater Crustacea. Wm. C. Brown Co. Publishers. Dubuque, Iowa. 277 pp.

  • Holsinger, J.R. 1967. Systematics, speciation, and distribution of the subterranean amphipod genus Stygonectes (Gammaridae). Bulletin of the United States National Museum, 259: 1-176.

  • Holsinger, J.R. 1978. Systematics of the subterranean amphipod genus Stygobromus (Crangonyctidae). Part II: Species of the eastern United States. Smithsonian Contributions to Zoology, 266: 1-144.

  • McLaughlin, P.A., D.K. Camp, M.V. Angel, E.L. Bousfield, P. Brunel, R.C. Brusca, D. Cadien, A.C. Cohen, K. Conlan, L.G. Eldredge, D.L. Felder, J.W. Goy, T. Haney, B. Hann, R.W. Heard, E.A. Hendrycks, H.H. Hobbs III, J.R. Holsinger, B. Kensley, D.R. Laubitz, S.E. LeCroy, R. Lemaitre, R.F. Maddocks, J.W. Martin, P. Mikkelsen, E. Nelson, W.A. Newman, R.M. Overstreet, W.J. Poly, W.W. Price, J.W. Reid, A. Robertson, D.C. Rogers, A. Ross, M. Schotte, F. Schram, C. Shih, L. Watling, G.D.F. Wilson, and D.D. Turgeon. 2005. Common and scientific names of aquatic invertebrates from the United States and Canada: Crustaceans. American Fisheries Society Special Publication 31: 545 pp.

  • U.S. Fish and Wildlife Service (USFWS). 1982. Endangered and Threatened Wildlife and Plants: Listings Hay's Springs amphipods as an Endangered species. Federal Register 47(25):5425-26.

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