APASIACAE

The Apasiacae probably originated east of the Aral Sea

Apasiacae is the name of a nomadic tribe belonging to the Massagetae. The Apasiacae lived in between of Oxus and the Tanais River, which in this context meant the east coast of the Aral Sea. That is, "Tanais" here means either the Syr Darya (Jaxartes River), or Amu Darya (Oxus River), to the west of Bactria. The Parthian king Arsaces I fled to these people ca. 230 B.C. from Seleucus II Callinicus.

Seleucid Empire :

The Parthians with the Apasiacae carried out revolts which broke out to regions to west of the Seleucid Empire and prevented the current war they were involved in.

Arsaces, who had remained closely allied with the nomads to the north, sensed his own weakness in the face of Seleucus's army and fled to the home of the Apasiacae, or “Scythians of the Waters.” Seleucus tried to cross the Jaxartes but, having suffered losses at the hands of the nomads, decided to return to Syria after receiving alarming news from the west. He made peace with Arsaces, who recognized his suzerainty.

Source :

https://en.wikipedia.org/
wiki/Apasiacae