Yes you definitely can, first you either got to have a DNS resolver or change the systems hosts files so they can lookup the dns address correctly
If the dns address "pterodactyl.example.com" points at the machine directly you still have to use the port of the pterodactyl dashboard You can also get a reverse proxy listening on port 443 (if you wan to use https, which I assume is the goal) on that machine or another machine which proxies the name "pterodactyl.example.com" to the right port
The next part is to get a certificate, you can either create a self-signed root CA and install the root cert on each system, or you have to get it with an ACME client using a dns-01 challange (since "pterodactyl.example.com" is not resolvable from the outside)
Then put the certificate either on the pterodactyl dashboard itself or the reverse proxy, there are also several reverse proxies that can fetch and reload the cert automatically, for example Caddy can do this with dns plugins
If you want I can help you with the configuration, I've done much of the same thing already