Branchinecta lindahli, commonly known as the Versatile fairy shrimp, belongs to the family Branchinectidae. This species can be found in a diverse range of habitats, including dry lake playas, predominantly during the cooler seasons of the year. Although often associated with alkaline habitats like dry lake playas characterized by moderate to high levels of dissolved solids composed of sodium salts and carbonates, this species is not limited solely to these environments. Branchinecta lindahli is frequently observed throughout the western United States, notably in states such as California, Arizona, and New Mexico.
Anatomy: The characteristics outlined below may exhibit variations influenced by environmental conditions, population dynamics, and the organism's age.
Head:
Second Antenna:
Male: The shrimp has a second antenna that is close to the body (proximal antennomere) with a small swelling (pulvillus) on the front-middle side near the base. This part is covered by tiny spine-like structures (spinules) and scales. The far end (distal antennomere) of the second antenna is compressed and curves inward, with two major bends. One bend is in the middle near part, and the other is at the far end, curving very strongly, almost at a right angle to the parts before it. The tip of the far end of the second antenna has a spatula-like projection that is hollow on the lower side. The back edge has a surface like a rasp, and the upper border near the end is not depressed.
Female: Females have a reduced second antenna compared to males and the first antenna is about as long as the second antenna.
Thorax:
Dorsolateral Process:
Male: Absent.
Female: The 4th to 9th segments of the thorax, and sometimes the first genital segment, have rounded lobes on both sides that are covered by skin denticles.
Thoracopods:
Male: limbs are curved with more spines instead of setae
Female: limbs are circular with more fine setae.
Reproductive Segments:
Male: A Pair of penes.
Female: The ovaries have two branches (biramous) with the lateral egg duct positioned at the beginning of the second genital segment. The groove for mating (amplexial groove) is not differentiated, and the pouch for carrying eggs (brood pouch) is cylindrical with no structures to receive the male’s second antennae during mating. The tip of the pouch ends under the fourth or fifth abdominal segment (sixth or seventh segments without legs).
Cyst:
The egg is round, with raised lines (cortical crests) forming many-sided (polygonal) areas.
Abdomen:
Abdominal segments possess no unique features and are consistent between sexes.
Tail:
Cercopods:
The tail appendages (cercopods) do not converge and are set with feathery bristles (plumose setae) along the middle and side borders.
Morphology:
Size: The size of this fairy shrimp ranges from 2 cm to 2.5 cm in length, contingent on prevailing environmental conditions.
Coloration: While the body is primarily transparent, subtle tints of colors such as greens and blues might be present.
Captivity and Growth:
Growth is influenced by multiple factors such as temperature, salinity, and care. These temperature ranges are based on our experience but do not represent the maximum or minimum.
Hatching Temperature Range: 50 to 72°F.
Temperature Range for Adults: 50 to 72°F.
Hatching: Nauplii emerge within 24 to 72 hours at temperatures ranging from 60 to 72 Fahrenheit.
Growth Rate: This species exhibits a moderate growth rate, achieving sexual maturity within approximately 9 to 13 days. The average lifespan spans 8 to 10 weeks.
Behavior: The Versatile fairy shrimp displays a swimming pattern encompassing vertical movements within the water column. These shrimps primarily engage in filter feeding on microorganisms. In the absence of readily available food, they resort to scraping substrate from the habitat floor for sustenance. Their movement is characterized by grace, with males displaying sporadic motions and females gliding gently. Continuous forward motion is typical, and stationary swimming is rare.
Reproduction: Males utilize their second antennae to swiftly latch onto females during mating, a process lasting only a few seconds.
References:
Obregón-Barboza, Hortencia, et al. "A Review of the Branchinecta (Branchiopoda: Anostraca) from the Baja California Peninsula: First Record of the Giant Fairy Shrimp B. gigas Lynch, 1937 from Mexico." Journal of Crustacean Biology, vol. 35, no. 3, 2015, pp. 433-440.