species unique to Thailand include a rich assortment of cave-dwelling
forms such as Puntius
Cave Sheatfish (PlanetCatfish),
subterraneus (FishBase), Kittipong’s
Cave Loach (FishBase),
Schistura spiesi (Loaches
Online), and an endemic genus:
the Cave Angel Fish
Other endemic freshwater fish include
the Redtailed Black Shark (ARKive),
Somphong’s Rasbora (ARKive),
an armored stickleback Indostomus
a chameleonfish Badis
Ornate Sand Loach (Loaches
Online), and several catfishes:
New to Science),
Endemic marine fish include the Thai Damselfish (FishBase),
a goby Myersina adonis
and the grunts Plectorhinchus
Amphibians found only in Thailand include the Doi Inthanon Rock Frog (Species New to Science), the Phu Luang Cliff Frog (Thai Wildlife Info), Smith's Wrinkled Frog (ARKive), the Khorat Big-headed Frog Limnonectes megastomias (Wildlife Extra), the Inthanon Stream Toad (siamensis), the Doi Chang Frog (flickr), Lekagul's Horned Frog (Species New to Science), Jarujin's Tree Frog (Zoological Soc. Japan pdf file), Fejervarya triora (p. 15 of Bryan L. Stuart pdf file), the Chiang Mai Litter Frog (Species New to Science), a newt Tylototriton uyenoi (Species New to Science), and Supachai's Caecilian (Internet Archive).
Reptiles that occur nowhere else include Gumprecht's Green Pitviper (Gernot Vogel), the Kanburi Pitviper (Siam-Info), the Banded Green Cat Snake (Siam-Info), Chanard's Water Snake (Species New to Science), the Orange-tailed Ground Gecko (Gernot Vogel), the Siamese Green-eyed Gecko (Nature's Window), the Saraburi Cave Gecko (siamensis), a recently described false bloodsucker Pseudocalotes khaonanensis (Reptile Database), Gyldenstolpe’s Legless Skink (eol), Miriam's Legless Skink (Reptile Database), and an endemic skink genus Jarujinia (Species New to Science).
Birds known solely from Thailand include the White-eyed River-martin (BirdLife Int'l). The Turquoise-throated Barbet (HBW) has recently been recognized as a full species. Deignan’s Babbler (Ayuwat) has sometimes been considered distinct from the more widespread Rufous-fronted Babbler Stachyris rufifrons and the Siamese Partridge Arborophila diversa (OBC) is sometimes treated as distinct from the Chestnut-headed Partridge Arborophila cambodiana.
Endemic mammals include the Limestone Rat Niviventer hinpoon (CERoPath), a horseshoe bat Rhinolophus thailandensis (Species New to Science), the Bala Tube-nosed Bat Murina balaensis (Species New to Science), and perhaps the poorly known Williamson’s Mouse-deer (IUCN Red List). The extinct Schomburgk's Deer Rucervus schomburgki (Wikipedia) was known only from Thailand.
Beetles exclusive to Thailand include a jewel beetle Chrysochroa corbetti (Living Jewels), the stag beetles Hexarthrius nigritus (SIZ) and Lucanus koyamai (flickr), a flower beetle Platynocephalus miyashitai (SIZ), a dung beetle Enoplotrupes sharpi (siamensis), a rove beetle Schedolimulus komatsui (Zootaxa pdf file), and a longhorned beetle Rhineimegopis rugicollis (Prioninae of the World). Other endemic insects include Aroon’s Silverline (SIZ), a hawk moth Leucophlebia frederkingi (Sphingidae of SE Asia), a katydid Lichnofugia rufa (SIZ), and the Khao Soi Dao Shadow Damsel (ARKive).
Other endemic invertebrates include the Shocking Pink Dragon Millipede (Zootaxa pdf file), the Giant Mountain Crab Potamon bhumibol (p. 1 of ONEP pdf file), a tarantula Chilobrachys huahini (Tarantupedia), a scorpion Heterometrus sejnai (p. 41 of Euscorpius 6 MB pdf file), and a mussel Modellnaia siamensis (ARKive). Endemic land snails include Alycaeus somnueki (jaxshells.org), Perrottetia dermapyrrhosa (Species ID), Amphidromus schomburgki (siamensis), Arinia panhai (Femorale), Sarika diadema (p. 3 of Raffles Museum 3 MB pdf file), Anauchen smokon (p. 5 of Chulalongkorn Univ. pdf file), and Carinartemis vesperus (Species New to Science). Attiliosa houarti (Eddie Hardy) is an endemic marine snail. A recently described sea slug Aiteng ater (IISE) is the sole member of a family known only from Pak Phanang Bay. The crustacean family Lipkecallianassidae is currently known only from a single specimen of Lipkecallianassa abyssa (p. 18 of AToL Decapoda pdf file) from deep waters in the Andaman Sea.
Vascular plant species restricted to Thailand include the orchids Paphiopedilum exul (rspg.org) and Pecteilis sagarikii (dnp.go.th), Magnolia sirindhorniae (ARKive), Sapria ram (rspg.org), Rhododendron ludwigianum (rspg.org), Bauhinia siamensis (dnp.go.th), Delphinium siamense (rspg.org), Gardenia saxatilis (rspg.org), Selliguea hirsuta (Ferns of Thailand), Wrightia sirikitae (WNS Stamps), Dracaena jayniana (Kew), Cycas petrea (Cycad Pages), and Impatiens phuluangensis (dnp.go.th). Endemic genera include the White Elephant Palm (PACSOA), an orchid Lesliea (IOPSE), a bamboo Temochloa (p. 19 of chm-thai.onep.go.th pdf file), Santisukia (rspg.org), Somrania (Species New to Science), Thawatchaia (CiNii), Khaosokia (NHM-London), Thepparatia (dnp.go.th), Marcania (dnp.go.th), Remirema (dnp.go.th), Tribounia (Species New to Science), and the gingers Cornukaempferia (Smithsonian) and Siamanthus (ARKive).
Portions of Thailand are included in two biodiversity hotspots: the Indo-Burma (CEPF) and the Sundaland (CEPF). The Chao Phraya (FEOW) is an important freshwater ecoregion and the Mekong River (WWF) has one of the world's richest freshwater faunas.