There aren't very many herp species on Hawaii to start with, and many of those are introduced. Here is a list of the species known to occur there (introduced species with an asterisk). I don't know which islands have which species.
SEA TURTLES
Green Seaturtle - Chelonia mydas
SOFTSHELL TURTLES
*Wattle-necked Softshell - Palea steindachneri
*Chinese Softshell - Pelodiscus sinensis
CHAMELEONS
*Yellow-crested Jackson's Chameleon - Chameleo jacksoni xantholophus
TRUE GECKOS
*Tokay Gecko - Gekko gecko gecko
*Stump-toed Gecko - Gehyra mutilata
*Common House Gecko - Hemidactylus frenatus
*Indo-Pacific Gecko - Hemidactylus garnoti
Common Indopacific Tree Gecko - Hemiphyllodactylus typus typus
Mourning Gecko - Lepidodactylus lugubris
*Orange-spotted Day Gecko - Phelsuma guimbeaui guimbeaui
*Broad-tailed Day Gecko - Phelsuma laticauda laticauda
IGUANIDS
*Western Knight Anole - Anolis equestris equestris
*Brown Anole - Anolis sagrei
*Common Green Iguana - Iguana iguana
SKINKS
Mottled Snake-eyed Skink - Cryptoblepharus poecilopleurus
Copper-tailed Skink - Emoia cyanura
*Azure-tailed Skink - Emoia impar
Rainbow Skink - Lampropholis delicata
Moth Skink - Lipinia noctua
OLD WORLD BLINDSNAKES
*Brahminy Blindsnake - Rhamphotyphlops braminus
The Brown Tree Snake (Boiga irregularis) may be sneaking into Hawaii as well, unfortunately!
If you want more specific detail, find a copy of Sean McKeown's book on Hawaiian Herps. It is the best source available.
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Chris Harrison