Maybe? I doubt it they said there are 48 combinaisons so.
4 Elemental skills x 6 Non elemental = 24
24 Base skill but your source skills also have their own results.
So double that and you already have your 48 skills.
The spider skill may be simply be a plain Geomancer skill.
That makes me think, ... you could have a 4 summoners party, all with a different elemental secondary spec.
So that mean you have 8 characters each fight !
or maybe the spiders isnt included in the combinations? cus blood rain is a normal skill and its createable with rain + necromancy
earth + summoning = spiders + scoundrel skill = ambush spiders which we have video of.. but perhaps spiders isnt included that combination count because it is also a base skill?
or maybe any geomancy skill + scoundrel skill = ambush spiders... but that would be strange...