Not every creature can “eat” the pheromone that the males drop.. like this tip so Dododex can see and add which creatures can eat it and which ones can’t.

I know some that cannot:

Megatherium

Stego

Tek Creatures

Anky

Doeds

Sarco

Baryonyx

Carno

Managarmr

Some that can eat:

Wyverns

Rex

Quetzal

Maewing

Trike

With more testing we could have it set up fully and implemented into DodoDex

Rex can use pheromones 100% used low level rex

Taming these things are confusing, but I believe I have figured out how they work.

Step 1 is to kill a wild rhynio (can be any gendrr) to get the pheromones, next it is best to make a trap, the best design i know of is basically a stone dino gate griffin trap, but with behemoth gates. Next you want to find a high level wild female rhynio. Think of the level of the rhynio as the taming effectiveness you will recieve 150 being max. Next you need to lower the rhynio to below 10% hp, you can net them to make this easier. Once it is below 10% hp you need a mount with a high drag weight in order to inherit the best stats, carch/giga have best chances. Feed the creature the phermone and mount it. The rhynio should impregnate it within a few seconds. DO NOT CRYOPOD THE DINO IT IMPREGNATED! YOU WILL LOOSE THE BABY! once your tame is impregregnated it will go through a gestation period and ask for cravings. It is important you furfill as many as possible as they have a major effect on the level the offspring will be and the stats inherited. Once the timer is complete your dino will fall unconscious and die, however you will now have a new perfect tame rhynio!

All of the currently known cravings for host creatures include

Giga eggs

Carchars eggs

Quetzal eggs

Golden hesperornis eggs

All kibbles

Shadow steak saute

Fria curry

Enduro stew

Focal chilli

Lazarus chowder

Veggie cakes

Black pearls

Achatina paste

Gasoline

Element

Rhino horns

Ammonite bile

Bee honey

Battle tartar

Use a direwolf on ark ascended to easily tell when it is below 10% health

Just a quick tip, Now only males will drop pheromones,

DONT KILL THE FEMALES!!!

It’s just came out with the new update.To tame it is kinda like the reaper.But instead of u getting impregnated it’s ur Dino but use a disposable Dino as once it gives birth the creature dies.from my own experience you need to kill one then get its pheromone gland then feed it to I am pretty sure ur creature once u found one u want to tame then find one u want to tame then eat the gland then keep attacking it until it impregnates u then u have to wait for a bit and u need to feed ur dino random things cuz it craves stuff.What I got was black pearls Lazarus chowder and absorant.I think the more u feed it the more older the baby is once it bursts from ur dinos chest then u need to raise it from there

to get a high level it depends on the host dino, the best ones are gigas, carchas, and brontos at the top. and rhynios get stats based on the host. even being said, its not guaranteed the stats such as it might not get the 30 points into health that the host dino had to put it into a example, and another factor is you have to give the host cravings. if not it might not be a max level either, they also dont get the hosts speed stat, their cravins contains: carcha egg, quetz egg, giga egg, golden egg, all the rockwell recipes and i mean all, element, absorbent substrate, black pearls, and gasoline. if helpful punch the sky

Here's just some things I've learned while taming these huge bugs.

•If you don't have something like a giga/carcha to impregnate, the 3rd best option would be a Brontosaurus for best stat quality for your baby bug. Though actually getting one to the Rhyniognatha will be quite difficult as you can't simply cryopod it and throw it once you found your Rhyniognatha (as of the Cryofridge and cryopod change in ASA). So you may need to walk it through the entire swamp...

• Keep your shoulder pets passive! This won't affect you if your using a large dino such as those listed above, though if using something smaller (though this is not recommended, most smaller dinos can't even consume the pheromone), you need to have your shoulder pets on passive so they don't attack the Rhyniognatha. I once did this mistake, and as I was going to feed my dino a pheromone, my otter on my shoulder killed the Rhyniognatha as it was on Attack Target.

•Final one, be fully prepared! Bring your pheromone and your creature your willing to impregnate before searching for a Rhyniognatha. This is because these guys love to aggro absolutely everything and get themselves killed, so if you went back to stock up on everything you need once you found one, chances are it is already dead.

Wish you luck!