What sort of weapons would a race of lizardmen use?

Question

(This is in a medieval fantasy setting)

Let me describe the creatures for you.

There are a warm-blooded species of semi-humanoid dragon-like creatures. They have the traditional draconic features, save for a lack of wings, but a humanoid build that is slightly hunched forward, akin to a Warhammer Fantasy Saurus, though bulkier around the waist/legs. They can run on all fours if needed and have snake-like necks; proportionally their necks would be about twice as long as a human's of comparable size, and heavily muscled.

-There's significant dimorphism among the species, with sizes and builds ranging from small (roughly the size of a large dog) dragon-like beings to very tall and large (horse/bear-sized) dragon-like creatures. Females tend to be larger than males. They have comparable muscle mass and strength/speed to creatures of that size, i.e. a dragon-like who is the size of a bear can probably hit as hard as a bear.

-Their scales make them moderately resistant to cutting an tearing with claws, teeth, and piercing weapons like spears and arrows, but they are only slightly effective against metallic bladed weapons and aren't very effective against blunt weapons.

They exist in a world with several other fantasy races. Elves, dwarves, humans, giants, orc-like creatures, and at least one species of pure, destructive evilness (think Dawkspawn from Dragon Age or Skaven from Warhammer Fantasy). Wars and diplomacy with all of the above (save the latter, of course, that's just pure warfare) has happened throughout their history.

Answer 1

Sounds like you've answered your own question

Man has concocted just about every melee weapon imaginable, what usually drives their acceptance is the their affectivity.

First, biggest question is their hands. Do they have large obstructing claws or fingers. Kind of hard to grip a handle with hands like a bear.

Next, as you have mentioned they strong natural armor so that rules out slashing weapons. But you have mentioned blunt weapons being effective so that rules in war hammers, maces, morning stars etc.

You did say steal could pierce their armor though not likely. Historically there are a tree of swords like foils or bayonets designed primarily for piercing armor. The construction is basically a strong slender metal shaft with a strong point on it (basically a needle). So they could have a sort of a fencing sword art. These would certainly be used in addition to hammers.

In terms of military composition

Less trained troops would likely use impact weapons as they are easier to use. Highly trained troops would likely prefer a pierce weapon (which would require more skill) because they could more swiftly and efficiently kill their opponent.

Update to modification:

In relation to conflict with other species. As mentioned before effectiveness is one of the chief most factors (relevant to this question) for weapon adoption. The weapons mentioned previously would likely be their default weapons, anything they can master to kill themselves they can likely use to kill someone else.

However

If they are in a prolonged conflict with another species, they would inevitably adopt weapons more suited for killing that species. This progression usually happens with a relation to their existing abilities as well as their experiences.

For instance: in fighting elves their fencing style would prove more effective than their blunt instruments while they notice the elves could be slashed as well. Thus they would then start adding edges to their pins making them more like sabers and traditional fencing swords increasing their overall lethality against the elves.

They could also notice the elves use bows which can kill other creatures so they too decide to use bows against the elves. This sort of adoption is more character driven.