Istalcurus
ISTALCURUS ĭs’ təl ky ŏŏr əs (̓Ιστάλκουρος). An Israelite who returned from the exile with Ezra in the reign of Artaxerxes (1 Esd 8:40). It is likely, however, that “Uthai the sons of Istalcurus” is a corruption of “Uthai and Zaccur” (KJV “Uthai and Zabbud”) in the parallel passage (Ezra 8:14).
International Standard Bible Encyclopedia (1915)
1 Esdras 8:40, corresponding to Zabbud in Ezr 8:14. In Swete’s text the name is Istakalkos.