(a) Commencement of Proceedings. Proceedings are commenced when:
(1) an initial shelter petition is filed;
(2) a petition alleging dependency is filed;
(3) a petition for termination of parental rights is filed; or
(4) a petition for an injunction to prevent child abuse under chapter 39, Florida Statutes, is filed.
(5) a petition or affidavit for an order to take into custody is filed; or
(6) any other petition authorized by chapter 39, Florida Statutes, is filed.
(b) File to Be Opened. Upon commencement of any proceeding, the clerk must open a file and assign a case number.