Where is the tiger salamander legal?

Genus Ambystoma (nonnative tiger salamander group)-(D)

How this rule works: § 671(b) defines (D) detrimental and (W) welfare. § 671.1(a) lists permit types; none covers pet keeping. The only possession permit, Animal Care, requires lawful possession in California before January 1992.

those species of mammals... and nonvenomous reptiles and amphibians native to Missouri

Ambystoma tigrinum is native to Missouri, which puts it in Class I rather than outside the Wildlife Code.

How this rule works: Class I is native Missouri mammals, reptiles and amphibians plus birds native to the continental United States. Class II is the venomous natives, mountain lion, wolf and black bear. Class III is cervids. An animal that is none of these is outside the Wildlife Code entirely.

monotypic species and subspecies of reptiles and amphibians not indigenous to Oklahoma are exempt from import and export requirements and commercial and noncommercial wildlife breeder's license

Ambystoma is native to Oklahoma, so the non-indigenous exemption does not reach it.

How this rule works: Navigate to Title 800, Chapter 25, Subchapter 25, Section 800:25-25-3. One of the most permissive exemption lists in the country, and one of the very few that names the fennec fox individually. Note what the exemptions are from: permits and breeder licences, not a ban. An unexempt animal is licensable, not prohibited.

Privately owned companion animals not intended for research or resale that are not native wildlife captured from the wild in Idaho

Captive bred stock is a conventional pet. Ambystoma mavortium is native to Idaho, so one taken from the wild in the state is wildlife and falls outside the definition.

How this rule works: Section 010.06 defines conventional pets, which sit outside the wildlife permit regime. Unusually explicit: it names ferrets, hedgehogs and sugar gliders in the rule text.

All persons other than a bona fide researcher, or a licensed pet shops and their transportation agents are prohibited from possessing any species of exotic amphibians unless they are kept indoors as pets in a manner that will prevent their escape or liberation into the wild. Keeping of these animals in any type of outdoor enclosure is prohibited.

Rhode Island's native amphibian list does not include the tiger salamander, so it is an exotic amphibian: keepable, but indoors only, and only a pet shop or researcher may import one.

How this rule works: One of the most species-specific schemes in the country. § 3.6 defines domestic animals, § 3.7 sets general prohibitions, § 3.9 governs permits, and § 3.17 is the long exempt list of animals that need no exotic animal possession permit. Anything not domestic, not native and not on the § 3.17 list needs a permit.