Upon entering the Arcane Hierophant class you obtain a “Companion Familiar”, the feature description says you have to dismiss your familiar but you may retain your animal companion if you have one.
Companion Familiar: Upon becoming an arcane hierophant, you must
dismiss your familiar, if you have one (You do not risk losing XP for
doing so.) You may retain any one animal companion you already
possess. You add your arcane hierophant class level to your druid or
ranger level for purposes of determining your animal companion’s bonus
Hit Dice, natural armor adjustment, and Strength/Dexterity adjustment
(see the sidebar The Druid’s Animal Companion, page 36 of the Player’s
Handbook). For example, a character who is a 4th-level druid/3rd-level
wizard/4th-level arcane hierophant has the animal companion of an
8th-level druid (+4 bonus HD, +4 natural armor, and +2
Strength/Dexterity adjustment, or an animal companion chosen from the
4th-level or 7th-level lists). In addition, your animal companion (if
any) gains many of the abilities that a familiar would normally
possess. You add your arcane hierophant class level to your arcane
spellcasting class level, and determine the Intelligence bonus and
special abilities of your animal companion accordingly (see the
sidebar Familiars, page 53 of the Player’s Handbook). For example, a
4th-level druid/3rd-level wizard/4th-level arcane hierophant has a
familiar companion equal to that of a 7th-level wizard and 8th-level
druid (Intelligence 9, alertness, improved evasion, share spells,
empathic link, deliver touch spells, speak with master, speak with
animals of its kind, devotion). The Hit Dice, hit points, attack
bonus, saving throws, feats, and skills of the familiar companion are
determined as normal for an animal companion. Due to the familiar
companion’s unusual Intelligence score, it may very well have more
skill points than other animals of its kind. The familiar companion is
a magical beast (augmented animal), but you can bestow harmless spells
on your familiar companion as if it were an animal instead of a
magical beast. If your familiar companion is killed or dismissed, you
do not lose XP. You can summon a new familiar companion by performing
a ceremony requiring 24 hours of uninterrupted prayer.
It is not clear to me what happens when you become an AH using classes that don’t have the Animal Companion feature (like a Cleric/Scout/Wizard, for example). Do you still get a companion familiar?
While i reckon it says “if any” in parenthesis, I find it weird the specifics of a class feature to be left to such an expression. Also, unlike the wild shape feature, it doesn’t state you don’t get it if you are not a druid.
On top of that (even if it should be related to the death of an companion familiar, but the wording seems to be vague about this implication) it also tells you how to get a new one by performing a ritual.
Me and my group always end up thinking the AH is a great class but its features are really poorly worded