Can secutor summon 2 monsters if he was not summoned by a gladiator beast?

You are correct! Secutor can only summon two monsters if he was summoned by a Gladiator Beast monster.

Here's why:

* Secutor's effect states: "If this card is Normal or Special Summoned by a Gladiator Beast monster: You can Special Summon 2 Gladiator Beast monsters from your hand, Deck, or Graveyard."

* Key Phrase: "If this card is Normal or Special Summoned by a Gladiator Beast monster".

* Requirement: This effect is activated only if Secutor was specifically summoned by another Gladiator Beast monster.

Therefore, if Secutor was not summoned by a Gladiator Beast monster, he cannot use this effect to summon two other Gladiator Beast monsters.