| Lepidurus packardi | |
|---|---|
 | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Subphylum: | Crustacea |
| Class: | Branchiopoda |
| Order: | Notostraca |
| Family: | Triopsidae |
| Genus: | Lepidurus |
| Species: | L. packardi |
| Binomial name | |
| Lepidurus packardi Simon, 1886 | |
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]
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]
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]
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]
Branchiopoda is a class of crustaceans. It comprises fairy shrimp, clam shrimp, Diplostraca, Notostraca and the Devonian Lepidocaris. They are mostly small, freshwater animals that feed on plankton and detritus.
The order Notostraca, containing the single family Triopsidae, is a group of crustaceans known as tadpole shrimp or shield shrimp. The two genera, Triops and Lepidurus, are considered living fossils, with similar forms having existed since the end of the Devonian, around 360 million years ago. They have a broad, flat carapace, which conceals the head and bears a single pair of compound eyes. The abdomen is long, appears to be segmented and bears numerous pairs of flattened legs. The telson is flanked by a pair of long, thin caudal rami. Phenotypic plasticity within taxa makes species-level identification difficult, and is further compounded by variation in the mode of reproduction. Notostracans are omnivores living on the bottom of temporary pools and shallow lakes.
Vernal pools, also called vernal ponds or ephemeral pools, are seasonal pools of water that provide habitat for distinctive plants and animals. They are considered to be a distinctive type of wetland usually devoid of fish, and thus allow the safe development of natal amphibian and insect species unable to withstand competition or predation by fish. Certain tropical fish lineages have however adapted to this habitat specifically.
Anostraca is one of the four orders of crustaceans in the class Branchiopoda; its members are referred to as fairy shrimp. They live in vernal pools and hypersaline lakes across the world, and they have even been found in deserts, ice-covered mountain lakes and Antarctic ice. They are usually 6–25 mm (0.24–0.98 in) long. Most species have 20 body segments, bearing 11 pairs of leaf-like phyllopodia, and the body lacks a carapace. They swim "upside-down" and feed by filtering organic particles from the water or by scraping algae from surfaces, with the exception of Branchinecta gigas, or "giant fairy shrimp", which is itself a predator of other species of anostracans. They are an important food for many birds and fish, and some are cultured and harvested for use as fish food. There are 300 species spread across 8 families.
Triops is a genus of small crustaceans in the order Notostraca. The long-lasting resting eggs of several species of Triops are commonly sold in kits as pets. The animals hatch upon contact with fresh water. Most adult-stage Triops have a life expectancy of up to 90 days and can tolerate a pH range of 6 to 10. In nature, they often inhabit temporary pools.
Triops longicaudatus is a freshwater crustacean of the order Notostraca, resembling a miniature horseshoe crab. It is characterized by an elongated, segmented body, a flattened shield-like brownish carapace covering two thirds of the thorax, and two long filaments on the abdomen. The genus name Triops comes from Greek ὤψ or ṓps, meaning "eye" prefixed with Latin tri-, "three", in reference to its three eyes. Longicaudatus is an Latin neologism combining longus ("long") and caudatus ("tailed"), referring to its long tail structures. Triops longicaudatus is found in fresh water ponds and pools, often in places where few higher forms of life can exist.
Linderiella occidentalis is a species of fairy shrimp native to California. It is a small crustacean in the family Chirocephalidae. It has a delicate elongated body, large stalked compound eyes, no carapace, and eleven pairs of swimming legs. It glides gracefully upside down, swimming by beating its legs in a complex, wavelike movement that passes from front to back. Like other fairy shrimp, L. occidentalis feeds on algae, bacteria, protozoa, rotifers and detritus.
The conservancy fairy shrimp is an endangered small crustacean in the family Branchinectidae. It ranges in size from about 1.25 centimetres (0.49 in) to 2.5 centimetres (0.98 in) long. This species is endemic to California in the United States.
The midvalley fairy shrimp, Branchinecta mesovallensis, is a small freshwater crustacean in the Branchinectidae family endemic to shallow ephemeral pools near the middle of California's Central Valley. These vernal pool ecosystems are home to other unique organisms adapted to the ephemeral nature of the water cycle in the pools in California's mediterranean climate.
Branchinecta longiantenna is a rare species of crustacean in the family Branchinectidae and the order Anostraca, the fairy shrimp. Its common name is longhorn fairy shrimp. It is endemic to California in the United States, where there are only four known populations. It is a federally listed endangered species of the United States.
The vernal pool fairy shrimp, Branchinecta lynchi, is a species of freshwater crustacean in the family Branchinectidae. It is endemic to the U.S. states of Oregon and California, living in vernal pools as well as non-vernal pool habitat. They range in size from 0.43 to 0.98 inches long. Vernal pool fairy shrimp are listed as a vulnerable species on the IUCN Red List, and has been listed as Federally Threatened species since 1994.
Lepidurus is a genus of small crustaceans in the order Notostraca. It is the larger of the two extant genera of the tadpole shrimps, the other being Triops. They are commonly found in vernal pools and survive dry periods with the help of long lasting resting eggs.
Streptocephalus woottoni, with the common name Riverside fairy shrimp, is a rare species of crustacean in the family Streptocephalidae. It is native to Southern California in the United States, and northern Baja California in northwest Mexico.
Great Valley Grasslands State Park is a state park of California, United States, preserving a parcel of remnant native grassland in the San Joaquin Valley. Such a temperate grasslands, savannas, and shrublands biome was once widespread throughout the whole Central Valley. The 2,826-acre (1,144 ha) park was established in 1982. Largely undeveloped, it was formed by combining two former state park units: San Luis Island and Fremont Ford State Recreation Area. Its chief attractions for visitors are spring wildflowers, fishing, and wildlife watching.
Triops australiensis, sometimes referred to as a shield shrimp, is an Australian species of the tadpole shrimp Triops.
The San Luis National Wildlife Refuge Complex is located in the northern San Joaquin Valley, within Merced County and Stanislaus County of California. The complex, with four federal National Wildlife Refuges, is managed by the U.S Fish & Wildlife Service.
Arctic tadpole shrimp Lepidurus arcticus is a species of tadpole shrimp which inhabits ephemeral pools, ponds or permanent freshwater lakes of Finland, Norway, Sweden, Svalbard, Greenland, Iceland, Russia and the Kuril Islands.
The Merced National Wildlife Refuge encompasses 10,262 acres (41.53 km2) of wetlands, native grasslands, vernal pools, and riparian areas in California. It was established in 1951 under the Lea Act to attract wintering waterfowl from adjacent farmland where their foraging was causing crop damage. In the last few decades, changes in agricultural practices and refuge management have reduced these wildlife/crop issues.
Lepidurus apus, commonly known as a tadpole shrimp, is a notostracan in the family Triopsidae, one of a lineage of shrimp-like crustaceans that have had a similar form since the Triassic period and are considered living fossils. This species is cosmopolitan, inhabiting temporary freshwater ponds over much of the world, and the most widespread of the tadpole shrimps. Like other notostracans, L. apus has a broad carapace, long segmented abdomen, and large numbers of paddle-like legs. It reproduces by a mixture of sexual reproduction and self-fertilisation of females.
