Streptocephalus henridumontis, also recognized as Dumont's Fairy Shrimp, is a member of the Streptocephalidae family. This species was officially documented and published by Maeda-Martínez et al. in 2005.
This species thrives in a range of habitats, including desert ephemeral pools characterized by the presence of calcium carbonates in the soil substrate and slight salinity. The substrate in these habitats can vary from sandy to loamy soils, and even to granitic soils (Rogers, D. C., 2014). It is commonly found in the Sonoran Desert region, which spans across northwestern Mexico and the southwestern United States, with frequent sightings in the southwestern U.S., particularly in Arizona and New Mexico (Maeda-Martinez et al., 1995; Thorp, J. H., & Rogers, D. C., 2015).
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 possesses a simple, short front appendage, typically with two lobes at its tip. Its second antennae feature a long, extended section (peduncle) that lacks a swelling (pulvinus), but instead, it displays approximately 12 cone-shaped protrusions on the inner side of its distal end. The inner upper side of the 'hand's' base boasts a forward-pointing, spine-like projection. There is a triangular extension (spur) with a tip resembling a swollen digit. A thin plate (lateral lamella) on the side forms a distinct angle with the distal end of the 'thumb' and the spur, creating a cavity medioventrally. The 'thumb's' distal end is bent (geniculate), featuring a prominent elbow on the lower side. Its upper edge is smooth (inerm), and the tip is sharp (acuminate). The 'finger' is doubly bent (bigeniculate), with two 'teeth' on the inner upper side near the base. The distal 'tooth' is broad at the base, its front margin projecting forward and upward into a digit-like formation. The proximal 'tooth' is shorter, somewhat pointed (subacuminate), and angled forward. The 'finger's' upper layer (dorsal lamella) is narrow at the first bend and straight-edged at the second. The 'finger's' tip is pointed, with a swollen area near the tip equipped with a spine-like structure on the lower side (Maeda-Martinez et al., 1995)
Female: The second antennae are smaller, broad, oval, flattened, and smooth, with no protrusions.
Thorax:
Dorsolateral Process (Lobes):
The thoracic segments are smooth and without lobes, which is characteristic of the genus
Thoracopods:
The structure is comparable across sexes, characterized by delicate setae along the limb's edges.
Reproductive Segments:
Male: A pair of penises.
Female: The ovaries are branched, with different lengths, stretching from the fourth to the eighth thoracic segments to the fourth to the sixth abdominal segments. The egg-carrying brood pouch ends at the sixth to seventh segments of the abdomen (Maeda-Martinez et al., 1995).
Abdomen:
Uniform across sexes without distinctive characteristics.
Telson & Cercopods:
The cercopods, or tail appendages, feature bristles along their inner and lateral margins, exhibiting pigmentation that ranges from red to orange.
Egg:
The egg is a rounded, closed sac with rib-like structures that form polygonal patterns. It is encased in a shell made of a single, soft, and porous layer called the spongy cortex (Maeda-Martinez et al., 1995).
Morphology:
Size: 2.0cm to 2.5cm in length, contingent on prevailing environmental conditions.
Coloration: body is transparent but may have hues of blue, pink, green.
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: 68 to 78°F.
Temperature Range for Adults: 68 to 78°F.
Hatching: At temperatures of 68 to 78 Fahrenheit, nauplii appear after 24 to 48 hours.
Growth Rate: This species has a moderate growth rate reaching sexual maturity at around 10 to 14 days with an average life span of 8 to 10 weeks.
Behavior: This species prefers to swim in open water, feeding on microorganisms in the water column, and is constantly swimming more or less in a stationary manner.
Reproduction: males use their second antenna to latch onto the females only taking but a few seconds to mate.
References:
Maeda-Martínez, Alejandro M., et al. "Two New Fairy Shrimp of the Genus Streptocephalus (Branchiopoda: Anostraca) from North America." Centro de Investigaciones Biológicas del Noroeste, S.C., Apartado postal 128, La Paz, Baja California Sur, 23000, Mexico. Centro de Bachillerato Tecnológico Agropecuario 198, Maneadero, 22900 Baja California, Mexico.
Rogers, D. C. (2014). Anostracan (Crustacea: Branchiopoda) zoogeography II. Relating distribution to geochemical substrate properties in the USA. Zootaxa, 3856(1), 1-49. Magnolia Press. https://doi.org/10.11646/zootaxa.3856.1.1
Thorp, J. H., & Rogers, D. C. (2015). Thorp and Covich’s Freshwater Invertebrates: Keys to Nearctic Fauna (4th ed.). Elsevie
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