Pisidium casertanum (Poli, 1791)

Rassam, Hanane, Ghamizi, Mohamed, Benaissa, Hassan, Clewing, Catharina & Albrecht, Christian, 2021, The fingernail clams (Bivalvia: Veneroida: Sphaeriidae) of Morocco: Diversity, distribution and conservation status, Biodiversity Data Journal 9, pp. 73346-73346 : 73346

Pisidium casertanum (Poli, 1791)

Ecological interactions

Native status

Autochtonous

Distribution

Cosmopolitan. More widely present in the Northern Hemisphere than the Southern one where it is more limited to high altitudes localities ( Kuiper 1983). Widespread throughout Morocco.

Notes

Shell dimensions: Mean length = 4.09 ± 0.7 mm; Mean height = 3.42 ± 0.59 mm; Mean width = 2.52 ± 0.76 mm.

Key features: Extremely variable, but can be separated from other species by its flattened umbo and shell (Fig. 6 ). Periostracum silky, coated with ferruginous deposits. The dorsal margin is relatively long. Cardinal teeth: C2 arched, C4 straight and short, C3 strongly curved, at times bifurcated posteriorly.

Remarks: The species is known to be highly variable morphologically ( Rassam et al. 2021b). The different morphological forms that the species can take are related to the effect of habitat conditions ( Piechocki 1989).

Figures

Figure 6. Pisidium casertanum from Ouzioua River a External view of the whole animal (left and right); b Dorsal view; c internal view of hinge plate of left and right valves.