What is the relationship between the depiction of Rudra in the Rigveda and later traditions associated with Shiva?

Rudra's depiction in the Rigveda differs from later descriptions of Shiva

Reconstructions of Harappan religion often rely on drawing parallels from later traditions to understand earlier ones. Archaeologists typically move from the known (present) to the unknown (past) in their interpretations. While this approach holds merit for objects like stone querns and pots, it becomes more speculative when applied to "religious" symbols.

For instance, let's consider the "proto-Shiva" seals. The earliest religious text, the Rigveda (compiled around 1500-1000 BCE), mentions a deity named Rudra, who later became associated with Shiva in Puranic traditions (from the first millennium CE). However, in the Rigveda, Rudra is not depicted as Pashupati (lord of animals) or as a yogi, contrary to later descriptions of Shiva. Therefore, this depiction does not align with the description of Rudra in the Rigveda. Some scholars have suggested that it might represent a shaman, introducing further speculation into its interpretation.