(DRAFT) - Taxonomy
Species ISOPOD, SOCORRO
Species Id ESIS452001
Date 13 MAR 96
TAXONOMY
NAME - ISOPOD, SOCORRO
OTHER COMMON NAMES - ISOPOD and SOCORRO
ELEMENT CODE -
CATEGORY - Aquatic Crustaceans
PHYLUM AND SUBPHYLUM - ARTHROPODA,
CLASS AND SUBCLASS - CRUSTACEA,
ORDER AND SUBORDER - ISOPODA,
FAMILY AND SUBFAMILY - SPHAEROMATIDAE,
GENUS AND SUBGENUS - THERMOSPHAEROMA,
SPECIES AND SSP - THERMOPHILUS,
SCIENTIFIC NAME - THERMOSPHAEROMA THERMOPHILUS
AUTHORITY -
TAXONOMY REFERENCES -
COMMENTS ON TAXONOMY -
Socorro Isopod
Thermosphaeroma thermophilus (Richardson, 1877)
KINGDOM: Animal GROUP: Crustacean
PHYLUM: Arthropod CLASS: Crustacea
ORDER: Isopoda FAMILY: Sphaeromatidae
Richardson (01) has described the Socorro isopod as follows:
"Head nearly three times as long, with its anterior margin widely
rounded. Eyes round and post-laterally situated. The first pair of
antennae, with a flagellum of eight articles, extend to the middle of
the first thoracic segment. The second pair of antennae reach the
posterior margin of the first thoracic segment; the flagellum
contains eleven articles. The thoracic segments are all similar with
the exception of the first, which extends laterally around the head,
almost touching the peduncle of the first pair of antennae with its
anterior angle. The ephemeral parts are continuous with the segments
with no indication of a separation from them. The abdomen is formed
of two distinct segments, the first of which is partly covered by the
last thoracic segment, the second is sub-triangular, rounded
posteriorly. The internal lamella of the uropods is moderately
Taxonomy - 1 (DRAFT) - Taxonomy
Species ISOPOD, SOCORRO
Species Id ESIS452001
Date 13 MAR 96
broad, well rounded, and extends to the posterior edge of the last
abdominal segment. The external lamella is half as long and half as
broad as the internal one, and is more pointed at its extremity.
The body is oblong-ovate with almost parallel sides. Its surface is
entirely smooth. The grayish-brown color of the body is everywhere
marked with small black spots and lines, which run together, forming
a broad, black band in the center of each one of the thoracic
segments. All the exposed edges of the body are tinged with bright
orange."
Males are larger than females with an approximately 2 mm
difference in length (09).
Richardson (01) originally placed this species under the genus
Sphaeroma (Sphaeroma thermophilum (Richardson, 1897)) but later
reassigned the isopod to the genus Exosphaeroma (Exosphaeroma
thermophilum (Richardson 1905)). In 1951, Rioja published the
mispelling E. thermophilum (10). Cole and Bane (03) placed the
Socorro isopod in the genus Thermosphaeroma where it remains today.
The U.S. Fish and Wildlife Service lists (50 CFR 17.11) this species
as Thermosphaeroma thermophilus such that the specific name gender is
consistent.
Taxonomy - 2 (DRAFT) - Status
Species ISOPOD, SOCORRO
Species Id ESIS452001
Date 13 MAR 96
STATUS
Coded Status
E: Federal Endangered
COMMENTS ON STATUS -
U.S. STATUSES AND LAWS:
The Socorro isopod (Thermosphaeroma thermophilus) has been
designated an Endangered species pursuant to the Endangered Species
Act of 1973 (50 CFR 17.11; P.L. 93-205, 87 Stat. 884;
16 U.S.C. 1531-1540), as amended. The species has this status
wherever found including the State of New Mexico.
This species is protected by the Lacey Act (P.L. 97-79, as
amended; 16 U.S.C. 3371 et seq.) which makes it unlawful to import,
export, transport, sell, receive, acquire, or purchase any wild
animal (alive or dead including parts, products, eggs, or offspring):
(1) in interstate or foreign commerce if taken, possessed,
transported or sold in violation of any State law or
regulation, or foreign law; or
(2) if taken or possessed in violation of any U.S. law,
treaty, or regulation or in violation of Indian tribal law.
It is also unlawful to possess any wild animal (alive or dead
including parts, products, eggs, and offspring) within the U.S.
territorial or special maritime jurisdiction (as defined in
18 U.S.C. 7) that is taken, possessed, transported, or sold in
violation of any State law or regulation, foreign law, or Indian
tribal law.
RESPONSIBLE FEDERAL AGENCIES:
USFWS -Responsible for the management/recovery, listing, and
law enforcement/protection of this species.
All Federal agencies have responsibility to ensure that any
action authorized, funded, or carried out by that agency is not likely
to jeopardize the continued existence of the species or result in the
destruction or adverse modification of Critical Habitat (50 CFR 402),
and to utilize their authorities to carry out programs for the
conservation of the species.
STATE STATUSES AND LAWS:
STATE: New Mexico
DESIGNATED STATUS: Endangered
ADMINISTRATIVE AGENCY: New Mexico Department of Fish and Game
STATE STATUTE: Wildlife Conservation Act of 1974, Regulation
624, Section 17-2-41 NMSA (1978).
Status - 1 (DRAFT) - Status
Species ISOPOD, SOCORRO
Species Id ESIS452001
Date 13 MAR 96
INTERNATIONAL STATUSES, TREATIES, AND AGREEMENTS:
Listed in the IUCN Red Book (1983) as Endangered.
ECONOMIC STATUSES:
The primary value of this species is as a part of the diversity
of life in this area.
78/03/27:43 FR 12691/ - Listed as Endangered.
83/12/08:48 FR 55100/55102 - Five year review.
Status - 2 HABITAT ASSOCIATIONS
HABITAT - AQUATIC
INLAND AQUATIC
LAND USE -
Streams and Canals
NATIONAL WETLAND INVENTORY CODES
NWI NWICLS NWIMOD NWISPEC
Riverine, upper perennial RB1
Lacustrine, littoral
COMMENTS ON HABITAT ASSOCIATIONS -
The entire habitat of this species is limited to a 1 m x 2 m x
0.3 m cement-lined animal watering tank, a smaller pool, and about 40
meters of open iron irrigation pipe (04). Water temperatures
throughout the system occupied by T. thermophilus range from 72 to 87
deg. F. The water surface is covered by algae (04). The floor of
the smaller pool is composed of 2 to 6 cm of sediment into which the
isopods burrow (07). Water flow through the system is about 3 gpm
which has been reduced from the historic flow of 151 to 172 gpm (8).
Note: the lacustrine and riverine National Wetland Type Keywords are
in the field "NWI" because of similarities of these habitats to the
classification.
Habitat Associations - 1 (DRAFT) - Food Habits
Species ISOPOD, SOCORRO
Species Id ESIS452001
Date 13 MAR 96
FOOD HABITS
TROPHIC LEVEL -
OMNIVORE
LIFESTAGE FOOD FOOD PART
General Detritus
General Algae
General Arthropods
Food Habits - 1 (DRAFT) - Environment Associations
Species ISOPOD, SOCORRO
Species Id ESIS452001
Date 13 MAR 96
ENVIRONMENTAL ASSOCIATIONS
G = General A = Adult
LIM = Limiting RA = Resting Adult
J = Juvenile FA = Feeding Adult
RJ = Resting Juvenile BA = Breeding Adult
FJ = Feeding Juvenile P = Pupae
L = Larvae E = Egg
RL = Resting Larvae
FL = Feeding Larvae
LIFESTAGE ENVIRONMENTAL ASSOCIATIONS
G Aquatic Features: Springs [flowing]
G
Environment Associations - 1 (DRAFT) - Life History
Species ISOPOD, SOCORRO
Species Id ESIS452001
Date 13 MAR 96
LIFE HISTORY
FOOD HABITS:
T. thermophilus is reported to feed on algae, detritus, and is
cannibalistic (05). Cannibalism involves feeding on wounded or
otherwise not entirely intact isopods and/or attacking a healthy
isopod (by severial isopods) (09).
HOME RANGE/TERRITORY:
There is no information indicating territoriality on the part of
T. thermophilus.
PERIODICITY:
T. thermophilus appears to be primarily nocturnal (09). This
species appears to avoid direct sunlight. Activity increases toward
late afternoon reaching a peak about an hour before sunset. Activity
remains high until just before dawn reaching its lowest level about
mid-morning (09).
MIGRATION PATTERNS:
There is no information indicating that T.thermophilum is
migratory.
COVER/SHELTER REQUIREMENTS:
There is no specific information on the cover/shelter
requirements of T. thermophilus.
REPRODUCTIVE SITE REQUIREMENTS:
There is no information about the reproductive site requirements
of T. thermophilus other than the description of the general habitat.
Males may sequester females in crevices in order to isolate them from
other reproductively active males (09).
REPRODUCTIVE CHARACTERISTICS:
Richardson (01) reports that male isopods have a bifurcate penis
located at the posterior end of the 7th peraeonal segment. This
structure is attached to the testes via a vas deferens. The testes
are paired and lie lateral and dorsal to the gut. Female isopods have
the genital openings at the base of the 5th peraeonal leg (01).
Males grasp females with their 4th or 5th peraeonal legs and
manipulate the female so that she is in a dorsal to ventral position
with her anterior end forward with respect to the male (09).
Prior to insemination, females must shed the posterior section
of the cuticle (01). Following shedding of the anterior cuticle, ova
are transferred forward by the female into the marsupium where embryo
development takes place. Complete development takes 30 to 40 days.
Juveniles may molt up to 8 times (09).
Schuster (05) reported a positive correlation between female
size and fecundity in a captive population of the Socorro isopod.
With laboratory animals, brood sizes ranged from 3 to 57 individuals
(mean = 15.8 +/- 11.4). Gestation in the laboratory was about 30
days and the recovery time between the release of a brood and
appearance of fully mature ovarioles was about 30 days (04). Gravid
Life History - 1 (DRAFT) - Life History
Species ISOPOD, SOCORRO
Species Id ESIS452001
Date 13 MAR 96
female numbers increased in April and declined to zero in August
(05).
PARENTAL CARE:
There is no indication that parental care is exercised by
T. thermophilus.
POPULATION BIOLOGY:
Population sizes probably vary seasonally and, perhaps, annually.
Hatch (06) reported a population estimate of 2,400 animals in 1976,
and Shuster (05) reported a population estimate of 2,449 animals in
1977.
SPECIES INTERRELATIONSHIPS:
No information exists on the relationships of T. thermophilus
with other species.
OTHER LIFE HISTORY DESCRIPTORS:
No other life history information is available for
T. thermophilus.
Life History - 2 (DRAFT) - Management Practices
Species ISOPOD, SOCORRO
Species Id ESIS452001
Date 13 MAR 96
MANAGEMENT PRACTICES
RESULT MANAGEMENT PRACTICE
Beneficial Restricting/regulating human disturbance of populations
Beneficial Maintaining/Controlling Water Flow
Beneficial Land Acquisition
Beneficial Water Right Acquisition
Beneficial Controlling pollution [thermal, chemical, physical]
Beneficial Stocking captive-reared wild-strain animals
Beneficial Transplanting wild animals
Adverse Irrigating
Existing Irrigating
COMMENTS ON MANAGEMENT PRACTICES -
The entire habitat for this species is limited to a 1 m x 2 m x
0.3 m cement-lined animal watering tank, a smaller pool, and about 40
meters of open irrigation pipe (04). The original spring source has
been capped and some water is drawn-off for other uses. An
unprotected valve could be turned-off at any time thus causing the
complete dewatering of this system (04). This system is
periodically cleaned by dredging by the private land owner (07).
Cook and Socorro Springs also exist within the immediate area,
and along with Sedillo Spring once fed a marsh extending one-half
mile east of Cook Spring. Whether T. thermophilus inhabited Cook,
Socorro, or other springs in this area is unknown, although this seems
likely. Both Cook and Socorro Springs are capped and all of the water
is diverted to the CIty of Socorro.
APPROVED PLAN
U.S. Fish and Wildlife Service. 1982. Socorro Isopod Recovery Plan
U.S. Fish and Wildlife Service, Albuquerque, New Mexico. 16 pp.
The prime objective of the recovery plan is to prevent the
extinction of the Socorro isopod by stabilizing and enhancing the
existing aquatic habitat derived from Sedillo Spring and initiate
recovery by establishing and maintaining at least an additional
captive population. Research at Sedillo Spring and on the
captive population (University of New Mexico) should include
continuation of data gathering to include: 1. population structure,
2. age structure, 3. food habits, 4. reproductive information, and
5. habitat requirements.
Management at Sedillo Spring should be aimed at protecting and
enhancing the habitat, including:
1. providing for a permanent flow of water (i.e. obtain an
agreement with the City of Soccorro and the present land
owner),
2. entering into a management agreement with the existing
private landowner for beneficial land management practices
(i.e. prevent over disturbance to the surrounding habitat
from removal of fill soil, gravel or sand for construction
Management Practices - 1 (DRAFT) - Management Practices
Species ISOPOD, SOCORRO
Species Id ESIS452001
Date 13 MAR 96
and mining),
3. prevent chemical contamination of water (management for
prevention of water contamination would be included in
a land amnagement agreement),
4. prevent loss of vegetative cover and soil cover (this
would be included in a land management agreement),
5. prevent introduction of predatory or competitive species
(i.e. exotic vertebrates, native vertebrates, and
invertebrates),
6. fencing the area around existing pools (this would aid
in protecting the habitat area from adverse actions and
human impacts),
7. obtaining land and water easements for construction of
additional Socorro isopod habitat nearby Sedillo Springs.
Creation of additional habitat for the Socorro isopod near the
existing site would reduce the likelihood of catastrophic elimination
of the species. This would require negotiation of water rights and
land purchase or easement. The Socorro isopod should be given the
full protection of state and Federal laws. Finally, information on
the Socorro isopod should be made available to the public through
various media.
Management Practices - 2 (DRAFT) - References
Species ISOPOD, SOCORRO
Species Id ESIS452001
Date 13 MAR 96
References
***** REFERENCES FOR ALL NARRATIVES EXCEPT N-OCCURRENCE *****
01 Richardson, H. 1897. Description of a new crustacean of the
genus Sphaeroma from a warm spring in New Mexico. U.S. Nat. Mus.
Proc. 20(1128):465-466.
02 Richardson, H. 1905. Contributions to the Natural history of the
Isopod. Proc. U.S. Nat. Mus. 27(1350):1-32.
03 Cole, G.A. and C.A. Bane. 1978. Thermosphaeroma subequalum
N. gen., N. sp. (Crustacea: Isopoda) from Big Bend National Park,
TX. Hydrobiologia 59(3):223-228.
04 U.S. Fish and Wildlife Service. 1982. Socorro isopod
(Thermosphaeroma thermophilum) Recovery Plan. U. S. Fish and
Wildl. Serv., Albuquerque, NM. 16 pp.
05 Schuster, S.M. 1977. The Socorro isopod. Unpubl. rep. on file
with the NM. Dept. of Game and Fish. 25 pp.
06 Hatch, M.D. 1976. The status of Exophaeroma thermophilum.
Unpubl. rept. on file with the NM. Dept. of Game and Fish,
Albuquerque.
07 Anon. [n.d.] Environmental impact assessment: Proposed endangered
determination for the Socorro isopod. Unpublished information on
file with the Off. of Endg. Sp., U.S. Fish and Wildl.
Serv., Wash., D.C.
08 Anon. [n.d.] Exosphaeroma thermophilum (Richardson). Unpubl.
info. on file with the Office of Endangered Species, U.S.
Fish and Wildl. Serv., Wash., D.C.
09 Anon. [n.d.] Untitled rept. on file with the Off. of Endg. Sp.
U.S. Fish and Wildl. Serv., Wash., D.C.
10 Bowman, T.E. 1981. Thermosphaeroma milleri and T. smithi, New
sphaeromatid isopod crustaceans from hot springs in Chihuahua,
Mexico with a review of the genus. J. Crustaceans Biol.
1(1):105-122.
***** REFERENCES FOR N-OCCURRENCE NARRATIVE ONLY *****
01 U.S. Fish and Wildlife Service. 1982. Socorro isopod
(Thermosphaeroma thermophilum) Recovery Plan. U. S. Fish and
Wildl. Serv., Albuquerque, NM. 16 pp.
02 Stanley, F. 1950. Socorro. The Oasis World Press, Inc. Denver,
Colo.
03 Hatch, M.D. 1976. The status of Exophaeroma thermophilum.
Unpubl. rep. on file with the NM Dept. of Game and Fish., Santa Fe.
References - 1