dcsimg
Image of Vernal pool tadpole shrimp
Creatures » » Animal » » Arthropods » » Branchiopods » » Triopsidae »

Vernal Pool Tadpole Shrimp

Lepidurus packardi Simon 1886

Behavior

provided by Animal Diversity Web

Vernal pool tadpole shrimp have a fused pair of eyes on the dorsal surface that are likely used to aid in locating both food and potential mates when reproduction is sexual. The nuchal organ is hypothesized to serve a chemosensory function.

Perception Channels: visual ; tactile ; chemical

license
cc-by-nc-sa-3.0
copyright
The Regents of the University of Michigan and its licensors
bibliographic citation
Wu, C. 2011. "Lepidurus packardi" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Lepidurus_packardi.html
author
Carey Wu, The College of New Jersey
editor
Keith Pecor, The College of New Jersey
editor
Tanya Dewey, University of Michigan-Ann Arbor
original
visit source
partner site
Animal Diversity Web

Conservation Status

provided by Animal Diversity Web

Vernal pool tadpole shrimp are currently considered endangered as a result of habitat loss and their restricted range.

US Federal List: endangered

CITES: no special status

State of Michigan List: no special status

IUCN Red List of Threatened Species: endangered

license
cc-by-nc-sa-3.0
copyright
The Regents of the University of Michigan and its licensors
bibliographic citation
Wu, C. 2011. "Lepidurus packardi" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Lepidurus_packardi.html
author
Carey Wu, The College of New Jersey
editor
Keith Pecor, The College of New Jersey
editor
Tanya Dewey, University of Michigan-Ann Arbor
original
visit source
partner site
Animal Diversity Web

Life Cycle

provided by Animal Diversity Web

Vernal pool tadpole shrimp hatch when proper conditions are met at the beginning of the spring season. If these conditions are not met, the eggs remain in a diapausal state for up to 10 years until proper conditions are met. After hatching, they reach sexual maturity within three weeks. This allows vernal pool tadpole shrimp to hatch, mature, and produce eggs quickly after pools refill. Vernal pool tadpole shrimp can produce multiple generations in a single wet season, and adults will remain present and reproductive in the pool until these temporary pools dry up completely.

Development - Life Cycle: diapause

license
cc-by-nc-sa-3.0
copyright
The Regents of the University of Michigan and its licensors
bibliographic citation
Wu, C. 2011. "Lepidurus packardi" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Lepidurus_packardi.html
author
Carey Wu, The College of New Jersey
editor
Keith Pecor, The College of New Jersey
editor
Tanya Dewey, University of Michigan-Ann Arbor
original
visit source
partner site
Animal Diversity Web

Benefits

provided by Animal Diversity Web

There are no adverse effects of the vernal pool tadpole shrimp on humans.

license
cc-by-nc-sa-3.0
copyright
The Regents of the University of Michigan and its licensors
bibliographic citation
Wu, C. 2011. "Lepidurus packardi" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Lepidurus_packardi.html
author
Carey Wu, The College of New Jersey
editor
Keith Pecor, The College of New Jersey
editor
Tanya Dewey, University of Michigan-Ann Arbor
original
visit source
partner site
Animal Diversity Web

Benefits

provided by Animal Diversity Web

Vernal pool tadpole shrimp provide no benefits to humans, although they are important members of native ecosystems.

license
cc-by-nc-sa-3.0
copyright
The Regents of the University of Michigan and its licensors
bibliographic citation
Wu, C. 2011. "Lepidurus packardi" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Lepidurus_packardi.html
author
Carey Wu, The College of New Jersey
editor
Keith Pecor, The College of New Jersey
editor
Tanya Dewey, University of Michigan-Ann Arbor
original
visit source
partner site
Animal Diversity Web

Associations

provided by Animal Diversity Web

Vernal pool tadpole shrimp provide a food source for organisms such as water birds and are hosts for parasitic organisms such as the metacercariae of flukes in the genus Echinostoma. This parasitism results in the castration of the vernal pool tadpole shrimp. Birds digging through the substrate aids in stirring up detritus into the water column for filter feeders to consume.

Commensal/Parasitic Species:

  • flukes (Echinostoma)
license
cc-by-nc-sa-3.0
copyright
The Regents of the University of Michigan and its licensors
bibliographic citation
Wu, C. 2011. "Lepidurus packardi" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Lepidurus_packardi.html
author
Carey Wu, The College of New Jersey
editor
Keith Pecor, The College of New Jersey
editor
Tanya Dewey, University of Michigan-Ann Arbor
original
visit source
partner site
Animal Diversity Web

Trophic Strategy

provided by Animal Diversity Web

Adults are omnivorous. They feed primarily on detritus found on the substrate of temporary pools, but they capture living organisms, such as fairy shrimp Anostraca and other invertebrates. Vernal pool tadpole shrimp consume plant detritus, various zooplankton, and insect larvae that they come across while digging through pool substrate. They use their ventral appendages to collect and filter food particles in the substrate and show a preference for animal detritus.

Animal Foods: carrion ; insects; aquatic crustaceans; zooplankton

Plant Foods: algae; phytoplankton

Other Foods: detritus ; microbes

Foraging Behavior: filter-feeding

Primary Diet: planktivore ; detritivore

license
cc-by-nc-sa-3.0
copyright
The Regents of the University of Michigan and its licensors
bibliographic citation
Wu, C. 2011. "Lepidurus packardi" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Lepidurus_packardi.html
author
Carey Wu, The College of New Jersey
editor
Keith Pecor, The College of New Jersey
editor
Tanya Dewey, University of Michigan-Ann Arbor
original
visit source
partner site
Animal Diversity Web

Distribution

provided by Animal Diversity Web

Vernal pool tadpole shrimp (Lepidurus packardi) are endemic to the California Central Valley, with the majority of individuals found in the Sacramento Valley. They have also been found in areas east of the San Francisco Bay to the Sacramento River Delta and in a few scattered locations in the San Joaquin Valley.

Biogeographic Regions: nearctic (Native )

license
cc-by-nc-sa-3.0
copyright
The Regents of the University of Michigan and its licensors
bibliographic citation
Wu, C. 2011. "Lepidurus packardi" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Lepidurus_packardi.html
author
Carey Wu, The College of New Jersey
editor
Keith Pecor, The College of New Jersey
editor
Tanya Dewey, University of Michigan-Ann Arbor
original
visit source
partner site
Animal Diversity Web

Habitat

provided by Animal Diversity Web

Vernal pool tadpole shrimp occur in a wide variety of seasonal habitats. These include vernal pools, clay flats, alkaline pools, ephemeral stock tanks, and roadside ditches and ruts. Habitats include small, clear, well vegetated vernal pools to exceedingly turbid, alkali scald pools or large winter lakes. Typically, they are found in habitats that are deeper than 12 centimeters, retain water for 15 to 30 days and do not experience wide daily temperature fluctuations. Average pond depth of wetlands is 15.2 centimeters. Vernal pool tadpole shrimp are not currently known to use highly saline habitats.

Range depth: 0.12 (low) m.

Average depth: 0.152 m.

Habitat Regions: temperate ; freshwater

Aquatic Biomes: temporary pools

license
cc-by-nc-sa-3.0
copyright
The Regents of the University of Michigan and its licensors
bibliographic citation
Wu, C. 2011. "Lepidurus packardi" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Lepidurus_packardi.html
author
Carey Wu, The College of New Jersey
editor
Keith Pecor, The College of New Jersey
editor
Tanya Dewey, University of Michigan-Ann Arbor
original
visit source
partner site
Animal Diversity Web

Life Expectancy

provided by Animal Diversity Web

The lifespan of vernal pool tadpole shrimp ranges from a few hours up to a few months, while pools still retain water.

license
cc-by-nc-sa-3.0
copyright
The Regents of the University of Michigan and its licensors
bibliographic citation
Wu, C. 2011. "Lepidurus packardi" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Lepidurus_packardi.html
author
Carey Wu, The College of New Jersey
editor
Keith Pecor, The College of New Jersey
editor
Tanya Dewey, University of Michigan-Ann Arbor
original
visit source
partner site
Animal Diversity Web

Morphology

provided by Animal Diversity Web

Vernal pool tadpole shrimp are typical members of the genus Lepidurus. They are distinguished from most other nearctic Lepidurus species by having a nuchal organ intersected by a line drawn between the posterior apices of the eyes. The nuchal organ is a large, light-sensitive tubercle behind the eyes thought to be used for perception. There is no set number of body rings (segments of the thorax and abdomen) or pairs of legs for the species, but most individuals fall in the ranges of 24 to 29 body rings and 30 to 35 pairs of legs. The first 11 body rings are defined as the thorax, with the remainder constituting the abdomen. The rings may be incomplete or coil the trunk more than once and they can bear multiple pairs of appendages.

The caudal lamina is truncate, meaning that a thin plate completely surrounds the abdominal region that could be considered the tail of the organism, and is 0.1 to 0.3 times the length of carapace. Mature individuals have triangular sulcus spines, with numerous small spines of varying shapes sometimes found in double rows separating the larger spines. Smaller individuals have large acute spines, 1.2 to 1.5 times as long as they are broad. Older individuals may have the largest sulcus spines rounded. The endites three, four, and five of the second thoracic appendages project beyond the carapace margin. In males, they may be used for grasping females during copulation.

Length of adult vernal pool tadpole shrimp ranges from 15 to 86 mm from the anterior margin of the carapace to the tip of the caudal lamina. They can reach very large sizes; one specimen from Stanislaus County, California measured 86 mm from the anterior carapace margin to the apex of the caudal lamina.

They may vary in coloration, depending on habitat, but are most commonly green. In highly turbid water, this species may be nearly translucent to buff colored with brown mottles. In slightly turbid to clear water, color may be more variable. Coloration may be light green, dark green, dark green mottled with brown, chocolate brown, brown with green mottles, or black.

Range length: 15 to 86 mm.

Other Physical Features: ectothermic ; heterothermic ; bilateral symmetry

Sexual Dimorphism: sexes alike

license
cc-by-nc-sa-3.0
copyright
The Regents of the University of Michigan and its licensors
bibliographic citation
Wu, C. 2011. "Lepidurus packardi" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Lepidurus_packardi.html
author
Carey Wu, The College of New Jersey
editor
Keith Pecor, The College of New Jersey
editor
Tanya Dewey, University of Michigan-Ann Arbor
original
visit source
partner site
Animal Diversity Web

Associations

provided by Animal Diversity Web

Vernal pool tadpole shrimp are subject to predation by water birds. Both mature individuals and diapausing eggs are consumed by birds. Some of the eggs that are consumed will pass through the birds digestive tract unharmed, which is how vernal pool tadpole shrimp disperse.

Known Predators:

  • waterfowl

Anti-predator Adaptations: cryptic

license
cc-by-nc-sa-3.0
copyright
The Regents of the University of Michigan and its licensors
bibliographic citation
Wu, C. 2011. "Lepidurus packardi" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Lepidurus_packardi.html
author
Carey Wu, The College of New Jersey
editor
Keith Pecor, The College of New Jersey
editor
Tanya Dewey, University of Michigan-Ann Arbor
original
visit source
partner site
Animal Diversity Web

Reproduction

provided by Animal Diversity Web

Vernal pool tadpole shrimp are either hermaphroditic or parthenogenic.

Reproduction occurs throughout the spring wet season when females average between 10 and 12 mm in carapace length. A female can produce thousands of cysts or fertilized eggs during her short lifespan and fecundity increases with size.

Females deposit eggs on vegetation and other objects located along pool substrates. These cysts and fertilized eggs are drought-resistant, sticky, and readily adhere to plant matter and sediment particles. When vernal pools dry, the eggs remain on the surface of the dried pool or become embedded in the substrate up to a few centimeters deep, where they enter a diapausal state. They remain there during the hot, dry summers and cold winters until the pools refill from rainwater and appropriate conditions for hatching occur. Some eggs hatch the following season when the pool refills, whereas others may remain dormant for up to 10 years before they hatch.

Breeding interval: It is unknown how frequently females may breed during their short lifespan.

Breeding season: Breeding occurs in the spring wet season.

Key Reproductive Features: seasonal breeding ; simultaneous hermaphrodite; parthenogenic ; sexual ; fertilization (External ); oviparous

Parental investment after fertilization and egg-laying is not present in vernal pool tadpole shrimp.

Parental Investment: no parental involvement; pre-fertilization (Provisioning, Protecting: Female)

license
cc-by-nc-sa-3.0
copyright
The Regents of the University of Michigan and its licensors
bibliographic citation
Wu, C. 2011. "Lepidurus packardi" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Lepidurus_packardi.html
author
Carey Wu, The College of New Jersey
editor
Keith Pecor, The College of New Jersey
editor
Tanya Dewey, University of Michigan-Ann Arbor
original
visit source
partner site
Animal Diversity Web

Lepidurus packardi

provided by wikipedia EN

Lepidurus packardi, the vernal pool tadpole shrimp, is a small, rare species of tadpole shrimp (Notostraca) found in temporary ponds of the western United States.[4]

Distribution

The freshwater crustacean is endemic to California, where it lives in the endangered vernal pool type of habitat, and other freshwater aquatic habitats including ponds, reservoirs, ditches, road ruts, and other natural and artificial temporary water bodies.

The animal is found in several regions of California, including the Central Coast, Sacramento Valley, San Joaquin Valley, and southern Sierra Nevada foothills.

The southeastern Sacramento Valley contains about 15% of the remaining vernal pool grassland habitat in the state, and it has about 35% of the known occurrences of L. packardi. 28% of all occurrences are in Sacramento County, California. Other areas with occurrences include the Don Edwards San Francisco Bay National Wildlife Refuge, several preserves in Tehama County, and the vicinity of the cities of Chico, Redding, and Red Bluff. It has been noted at the Sacramento National Wildlife Refuge, Travis Air Force Base, and the Jepson Prairie Preserve. In the San Joaquin Valley it has been noted at the Merced and San Luis National Wildlife Refuges. There are occurrences in the Sierra foothills region in Tulare, Fresno, Merced, and Stanislaus Counties.[5] It occurs outside California in the Agate Desert of Oregon.[6]

Description

Lepidurus packardi is about 5 centimeters (2.0 in) long. It has a shield-like carapace up to 3.5 cm (1.4 in) long. It has compound eyes, up to 48 pairs of phyllopods (swimming appendages), and two cercopods, pincer-like appendages at the end of its telson, or tail segment. It is similar to,[6] but distinct from,[7] the related species Lepidurus couesii. The sexes can be distinguished by noting the egg sacs attached to the eleventh phyllopods of the female.[6]

The adult is omnivorous, collecting food items with its phyllopods as it swims, climbs on vegetation, or digs in sediment.[6] It is an ecosystem engineer in that it causes bioturbation, producing so much turbidity when it digs through the sediment that it may alter the ecology of its pool habitat by reducing plant cover.[8]

Reproduction occurs when temporary pools fill with water. Larger females have higher fecundity, the clutch size ranging from eight to 61 eggs. The eggs can withstand a period of desiccation when the pool is dry; they will then hatch within three weeks of the pool refilling, often much more quickly. Desiccation is not required for hatching, however. The larva hatches as a metanauplius. It undergoes ecdysis, or molting, several times, growing more phyllopods each time. L. packardi takes about 38 days to mature, reproduces around its 54th day of life, and lives about 144 days.[6] It is sexually mature when it is 10–12 mm (0.4–0.5 in) in carapace length. Fecundity is much reduced in individuals which are infested with a parasitic echinostome fluke.[9]

Conservation

Lepidurus packardi is a listed federally as an endangered species[2][3] and by the IUCN RedList.[1]

Threats to L. packardi include anything that destroys, degrades, or fragments its ephemeral pool habitat. Nine percent of historical vernal pool habitat remains today, and it is fragmented and isolated. Expanding urban development is the cause of habitat destruction in many areas. Agricultural development is another cause. The construction of the University of California, Merced, campus was scheduled to alter the habitat in the area, but it also included plans for protection of over 20,000 acres (8,100 ha).

Habitat can also be degraded when the local hydrology is altered, making the land too dry or permanently wet. There are many local conservation projects tailored to the needs of each region.[5]

References

  1. ^ a b Inland Water Crustacean Specialist Group (1996). "Lepidurus packardi". IUCN Red List of Threatened Species. 1996: e.T11615A3296166. doi:10.2305/IUCN.UK.1996.RLTS.T11615A3296166.en. Retrieved 17 November 2021.
  2. ^ a b "Vernal pool tadpole shrimp (Lepidurus packardi)". Environmental Conservation Online System. U.S. Fish & Wildlife Service. Retrieved 23 April 2023.
  3. ^ a b 59 FR 48136
  4. ^ ITIS Report: Lepidurus packardi (TSN 684669)
  5. ^ a b USFWS. Lepidurus packardi Five-year Review. September 2007.
  6. ^ a b c d e Lepidurus packardi. The Nature Conservancy.
  7. ^ D. Christopher Rogers (2001). "Revision of the Nearctic Lepidurus (Notostraca)". Journal of Crustacean Biology. 21 (4): 991–1006. doi:10.1651/0278-0372(2001)021[0991:ROTNLN]2.0.CO;2. JSTOR 1549720.
  8. ^ Russell C. Croel & Jamie M. Kneitel (2011). "Ecosystem-level effects of bioturbation by the tadpole shrimp Lepidurus packardi in temporary pond mesocosms" (PDF). Hydrobiologia. 665 (1): 169–181. doi:10.1007/s10750-011-0620-9. S2CID 24270007.
  9. ^ J. S. B. Ahl (1991). "Factors affecting contributions of the tadpole shrimp, Lepidurus packardi, to its oversummering egg reserves". Hydrobiologia. 212 (1): 137–143. doi:10.1007/BF00025995. S2CID 26307328.

license
cc-by-sa-3.0
copyright
Wikipedia authors and editors
original
visit source
partner site
wikipedia EN

Lepidurus packardi: Brief Summary

provided by wikipedia EN

Lepidurus packardi, the vernal pool tadpole shrimp, is a small, rare species of tadpole shrimp (Notostraca) found in temporary ponds of the western United States.

license
cc-by-sa-3.0
copyright
Wikipedia authors and editors
original
visit source
partner site
wikipedia EN