With a maximum length of 8 cm, Glycymeris pilosa is characterized by a robust, equivalve and inequilateral shell (generally round-shaped) with one side slightly flattened.

The umbo is tilted posteriorly and features a distinctive reticulated pattern, created by the intersection of concentric and radial striae (the latter being relatively wide-spaced). While the ventral margin has few teeth, the hinge is notable for its numerous teeth. The external coloration ranges in brownish hues, while the interior is white with faint darker shades. This species is mainly distributed across the Mediterranean Sea and the Eastern Atlantic (around Gibraltar and northern Morocco).

It thrives in shallow waters, even in environments with low oxygen levels.

Often confused with its close relative Glycymeris Bimaculata, the two species can be clearly distinguished by several key traits:

1. In Pilosa, the inner surface shows large purple-chocolate colored spots;
2. In Bimaculata hair coverage is almost absent, except near the ventral margin, where it is hidden under a thick layer. As its name suggests, the Pilosa has visible, well-developed hair-like structures.