Timor-Leste
Endemic reptiles include the Timor Ground Snake Stegonotus nancuro (ResearchGate), the Timor Worm Snake Indotyphlops laca (Species New to Science), and the Nino Konis Santana Bent-toed Gecko Cyrtodactylus santana (ZooKeys). The recently described Timor Longneck Turtle Chelodina timorensis (CRF WM pdf) is often considered a subspecies of Chelodina mccordi. Among over a dozen recently discovered undescribed species of reptiles from Timor-Leste is a bent-toed gecko of the genus Cyrtodactylus (FPCD) and photos of additional species can be accessed from (ZooKeys) and (Mark O'Shea).
A likely undescribed species of a frog of the genus Kaloula (p. 10 of Mark O'Shea pdf) has also been discovered.
The Timorese Horseshoe Bat Rhinolophus montanus (iNaturalist) (Internet Archive) is known only from four locations. The extinct Musser's Giant Rat Coryphomys musseri (ResearchGate) is also known only from Timor-Leste.
Endemic freshwater fish include a hardyhead Craterocephalus laisapi (aqua WM) from the Ira Siquero River and apparently an undescribed species of goby Lentipes from the Vero River (p. 33 of La'o Hamutuk pdf) (BHL). Recently described marine fishes known only from Timor-Leste include Santana's Dwarf Goby Eviota santanai (GBIF) and a triplefin blenny Helcogramma atauroensis (ResearchGate).
Insects known solely from Timor-Leste include a butterfly Rapala christopheri (iNaturalist) (BHL), a tussar moth Antheraea lorosae (BHL), the ground beetles Mecyclothorax timorensis (BHL), a ground beetle Mecyclothorax timorensis (p. 4 of Australian Museum pdf), a tortoise beetle Notosacantha timorensis (GBIF), the leaf beetles Paropsisterna tais (PLAZI) and Paropsisterna tatamailau (PLAZI), the rove beetles Stenus hatobuilico and Stenus ramelau (both at ResearchGate), the caddisflies Ulmerochorema hatubuilico and Hydroptila bellisi (both at Zootaxa pdf), and the ants Tetramorium rekhefe (GBIF) and Strumigenys berkalial (GBIF).
Other invertebrates currently known only from Timor-Leste include a cave-dwelling whip spider Sarax timorensis (ZooKeys), the amphipods Talorchestia dili (GBIF) and Ampithoe atauro (BHL) and Quadrimaera metinaro (BHL), and several land snails: Phaedusa ramelauensis (WMSD), Amphidromus richardi (Natuurtijdschriften pdf), Amphidromus timorensis (Malacology-asia.com), Amphidromus vincekresneri (GBIF), Parachloritis afranio and Parachloritis herculea (both at ResearchGate), Trochomorpha vincekessneri (GBIF), and Apoecus ramelauensis (WoRMS).
Two recently described orchids are known only from Timor-Leste: Habenaria ankylocentron (p. 8 of Univ. Wien WM pdf) and Pterostylis timorensis (p. 15 of Univ. Wien WM pdf). Other plants known solely from Timor-Leste include Eucalyptus orophila (Don Franklin), Glochidion timorense (GBIF), an orchid Thelymitra forbesii (iNaturalist), Sporobolus amaliae (Naturalis), Bromus timorensis (JSTOR) (IUCN), Melicope timorensis (GBIF), Gynura steenesii (GBIF), and Strobilanthes orientalis (Semantic Scholar WM) (IUCN).
Timor-Leste is part of the Timor and Wetar Deciduous Forests terrestrial ecoregion (EoE), the Lesser Sunda Islands freshwater ecoregion (FEOW WM), the Sunda Islands coral reef hotspot (Columbia Univ. WM pdf), and the Wallacea biodiversity hotspot (Biodiversity Hotspots WM). Additional endemic species from the island of Timor that are shared with Indonesia can be found here.