R
- Radiocentrum avalonense — Catalina mountain snail
- Radioconus goeldi
- Radioconus riochcoensis
- Radiodiscus amdenus
- Rafetus euphraticus — Euphrates Softshell Turtle
- Rafetus swinhoei
- Rallus semiplumbeus — Bogotá Rail
- Rallus wetmorei — Plain-flanked Rail
- Ramanella mormorata
- Ramanella palmata
- Ramphocinclus brachyurus — White-breasted Thrasher
- Rana amamiensis — Amami Tip-nosed Frog
- Rana cerigensis — Karpathos Frog
- Rana charlesdarwini
- Rana chevronta
- Rana chichicuahutla
- Rana cretensis — Cretan Frog
- Rana dunni
- Rana holsti — Holst's Frog
- Rana ishikawae — Ishikawa's Frog
- Rana johni
- Rana kuangwuensis
- Rana mangyanum
- Rana minima
- Rana muscosa — Mountain Yellow-legged Frog
- Rana narina — Ryukyu Tip-nosed Frog
- Rana okinavana — Ryūkyū Brown Frog
- Rana omiltemana — Guerreran Leopard Frog
- Rana onca — Relict Leopard Frog
- Rana psaltes — Kampira Falls Frog, Yaeyama Harpist Frog
- Rana pueblae
- Rana pyrenaica — Pyrenean Frog
- Rana sevosa — Dusky Gopher Frog, Mississippi Gopher Frog
- Rana shqiperica — Albanian Water Frog
- Rana subaquavocalis — Ramsey Canyon Leopard Frog
- Rana subaspera — Otton Frog
- Rana supranarina
- Rana tenggerensis
- Rana tlaloci — Tlaloc's Leopard Frog
- Rana utsunomiyaorum
- Rana vibicaria
- Rana wuchuanensis
- Ranodon sibiricus — Central Asian Salamander, Semirechensk Salamander
- Rasbora wilpita
- Rattus baluensis — Summit Rat
- Rattus enganus — Enggano Rat
- Rattus montanus — Nillu Rat
- Reithrodontomys spectabilis — Cozumel Harvest Mouse
- Relictus solitarius — Relict Dace
- Rhabdalestes leleupi
- Rhacophorus angulirostris
- Rhacophorus arvalis
- Rhacophorus aurantiventris
- Rhacophorus calcadensis
- Rhacophorus lateralis
- Rhacophorus pseudomalabaricus
- Rhagomys rufescens — Brazilian Arboreal Mouse
- Rhamphophryne macrorhina
- Rhamphophryne nicefori
- Rhamphophryne rostrata
- Rhantus alutaceus
- Rheocles wrightae — Zona
- Rhinobatos horkelii — Brazilian guitarfish
- Rhinoceros sondaicus — Javan Rhinoceros
- Rhinoceros unicornis — Great Indian Rhinoceros, Indian Rhinoceros
- Rhinocypha hageni
- Rhinocypha ogasawarensis
- Rhinocypha uenoi
- Rhinoderma rufum
- Rhinolophus convexus — Convex Horseshoe Bat
- Rhinolophus hilli
- Rhinolophus imaizumii — Imaizumi's Horseshoe Bat
- Rhinolophus keyensis — Insular Horseshoe Bat
- Rhinolophus maclaudi — Maclaud's Horseshoe Bat
- Rhinolophus ziama
- Rhinomyias albigularis — White-throated Jungle-flycatcher
- Rhinopithecus avunculus — Tonkin Snub-nosed Monkey
- Rhinopithecus bieti — Black Snub-nosed Monkey, Yunnan Snub-nosed Monkey
- Rhinopithecus brelichi — Gray Snub-nosed Monkey, Guizhou Snub-nosed Monkey
- Rhinoptera brasiliensis — Brazilian Cownose Ray
- Rhinoptilus bitorquatus — Jerdon's Courser
- Rhipidolestes okinawanus
- Rhithrodytes agnus
- Rhodonessa caryophyllacea — Pink-headed Duck
- Rhogeessa alleni — Allen's Yellow Bat
- Rhogeessa mira — Least Yellow Bat
- Rhopornis ardesiacus — Slender Antbird
- Rhynchobatus luebberti — African wedgefish, Lubbert's guitarfish, Spikenose wedgefish
- Rhynchocyon chrysopygus — Golden-rumped Elephant Shrew, Golden-rumped Sengi
- Rhynchopsitta pachyrhyncha — Thick-billed Parrot
- Rhynochetos jubatus — Kagu
- Rhysoconcha variumbilicata
- Rhytida clarki
- Rhytida oconnori
- Risiocnemis seidenschwarzi
- Rollandia microptera — Titicaca Flightless Grebe
- Romanichthys valsanicola — Asprete
- Romerolagus diazi — Volcano Rabbit
- Rostroraja alba — Bottlenose skate, Spearnose skate, White skate
- Ruatara koarana
- Rukia ruki — Faichuk White-eye
- Rutilus meidingerii
Read more about this topic: IUCN Red List Endangered Animal Species