Branchipodopsis affinis

Nov 3, 2023
3 min read

(WIP Come Back Soon)

Taxonomy and Classification

• Phylum: Arthropoda

• Class: Branchiopoda

• Order: Anostraca

• Family: Branchipodidae

• Genus: Branchiopodopsis

• Species: B. affinis

• Authority: G.O. Sars, 1901

Branchipodopsis affinis, commonly known as the Affinis fairy shrimp, belongs to the order Anostraca and the family Branchipodidae. First described by G.O. Sars in 1901, this species is adapted to life in ephemeral rock pools—small, transient freshwater habitats that form after seasonal rainfall, particularly in arid and mountainous regions.

These pools are typically shallow (less than 50 cm deep), with very low mineral content and electrolytic conductivity (often below 10 μS/cm), resulting in poor buffering capacity and wide pH fluctuations ranging from 4 to 11. The water is usually clear and nutrient-poor, reflecting the minimal soluble salts and minerals from surrounding rock. Such conditions are common in parts of southern Africa, including the Drakensberg mountains, Western Cape, and Eastern Free State, where B. affinis and other Branchipodopsis species are found.

The distribution of B. affinis is primarily centered in southern Africa, though recent records have extended its known range to parts of the Middle East, including Iran (West Azerbaijan), suggesting a broader but still sporadic presence across suitable habitats

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 structure known as a Clypeus, characterized by a wide base process that divides into two lobes at its extremity. The external lobe is typically rounded and smooth, although it may exhibit a small sharp projection on its inner side, which might not be visible in certain instances. Conversely, the inner lobe is more cone-shaped with a sharp point. Additionally, there is a small, rounded, leaf-like feature (lamelliform process), and the joint at the tip is distinctly curved inward, broad, and blunt (Kangarloei, Behrooz Atashbar & Roohi, 2021).

Female: The second antennae are smaller, broad, oval, flattened, and smooth, with no protrusions.

Thorax:

Dorsolateral Process:

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: Resting egg broods are usually small, often comprising less than 80 eggs, and are produced almost daily. The egg-carrying pouch, known as the brood pouch, is oval in shape (Brendonck et al., 2000).

Abdomen:

Uniform across sexes without distinctive characteristics.

Telson & Cercopods:

Male: The cercopods, or tail appendages, feature outer edges that curve outward significantly, adorned with bristles (setae) spanning their full length. Additionally, small, spine-like bristles are present along the entire inner edges. (Thiéry and Jean, 2008).

Female: The tail appendages feature straight edges adorned with lengthy, feathery bristles known as plumose setae along the outer edges and the distal two-thirds of the inner edges (Thiéry and Jean, 2008).

Egg:

The cyst, or the closed sac-like structure, has a surface that is decorated with dips (indentations) and raised lines (ridges). It is round in shape and has rib-like structures that form many-sided (polygonal) areas.

Male morphology:• Clypeus: Broad, bilobed basal process with conical inner lobe and rounded outer lobe

• Cercopods: Strongly convex outer margins with setae; inner margins lined with spine-like setae

• Abdominal spines: Present on ventral surface of final segment

Conservation Status

• As of now, B. affinis has not been formally assessed by the IUCN Red List C

Morphology: