Uruguay

Freshwater fish restricted to Uruguay include the Rocha Pearlfish Austrolebias viarius (FishBase), the Ashy Pearlfish Austrolebias cinereus (It Rains Fish), Austrolebias reicherti (Killifish Incidents), Austrolebias gymnoventris (It Rains Fish), Austrolebias queguay (BHL) (iNaturalist), Austrolebias affinis (Austrolebias Project), a livebearer Cnesterodon holopteros (ResearchGate), a characin Oligosarcus platensis (GBIF), and the cichlids Gymnogeophagus tiraparae (SciELO Brasil) and Gymnogeophagus peliochelynion (peces criollos WM).

A rodent found nowhere else is Cook’s Hocicudo Oxymycterus josei (iNaturalist) (p. 2 of Ramsar pdf). The only definite specimen of the Brazilian Tuco-tuco Ctenomys brasiliensis (ResearchGate) (GBIF) is from Uruguay, but will likely prove to be the senior synonym to another more widespread species (most likely Ctenomys pearsoni (iNaturalist) which is known also from Argentina). A recently described bat Myotis pampa (Vertebrate Zoology) is currently known only from specimens collected in Uruguay, but almost certainly occurs in adjacent pampas regions in Argentina and Brazil. Two subspecies of Pampas Deer are endemic to Uruguay: Ozotoceros bezoarticus arerunguaensis (iNaturalist) (YouTube) and Ozotoceros bezoarticus uruguayensis (iNaturalist) (bib.fcien.edu.uy WM pdf).

Langone's Redbelly Toad Melanophryniscus langonei (SciELO Brasil pdf) (p. 21 of la diaria pdf) is an endemic amphibian. Melanophryniscus orejasmirandai (kwet.de WM) is now usually considered a synonym of the more widespread Melanophryniscus pachyrhynus (ResearchGate).

A recently described endemic lizard is Liolaemus gardeli (GBIF). The extinct Cabo Polonio Whiptail Contomastix charrua (p. 149 of la diaria pdf) (IUCN) appears to be a synonym of the more widespread Bibron's Whiptail Contomastix lacertoides (see ResearchGate).

Insects unique to Uruguay include the grasshoppers Orienscopia sanmartini (OSF) and Borellia alejomesai (OSF), a stick insect Brizoides minutissima (GBIF), the ants Pheidole industa (AntWiki) and Acromyrmex charruanus (AntWiki), a stink bug Liscocephala fumosa (GBIF), a stonefly Paragripopteryx munoai (PLOS), the mayflies Cloeodes guenoa (GBIF) and Tricorythodes biluhue (GBIF), a trumpet leaf miner moth Astrotischeria atlantica (GBIF), a crambid moth Pseudometachilo subfaunellus (Smithsonian), a plume moth Postplatyptilia uruguayensis (p. 99 of Naturalis WM pdf), a flower beetle Anacassis nigroscutata (iNaturalist) (Dr. Lech Borowiec WM), a ground beetle Lachnophorus montoroi (GBIF), a blister beetle Epicauta luctifera (fig. 40 at scielo.br), a rove beetle Edrabius uruguayensis (GBIF), the weevils Huaca capi (GBIF) and Araptus uruguayensis (barkbeetles.info), and several longhorn beetles: Odontocera monnei (MNRJ WM), Eryphus tacuarembo (MNRJ WM), and Ancylodonta glabripennis (MNRJ WM).

Other endemic invertebrates include a tarantula Grammostola andreleetzi (birdspiders.com WM), a nemesiid spider Chaco costai (ResearchGate), a crab spider Uraarachne brevipes (figs. 1a-d at ResearchGate), a wolf spider Lycosa carbonelli (BHL), a goblin spider Neotrops labarquei (GBIF), an orb-weaving spider Chrysometa pena (GBIF), a harvestman Psammogeaya arenata (iNaturalist), the scorpions Bothriurus rochensis (iNaturalist) and Bothriurus buecherli (flickr), a millipede Sandalodesmus joachimadisi (GBIF), a freshwater snail Potamolithus filipponei (fig. 8 at Internet Archive), and several land snails: Austroborus lutescens (flickr), Bulimulus corderoi (Femorale WM), and Bulimulus gorritiensis (WMSDB).

Vascular plants found solely in Uruguay include the cacti Parodia werdermanniana (cactusinhabitat WM) and Wigginsia gladiata (notocactus.eu), a bromeliad Tillandsia uruguayensis (bromeliad.nl), the orchids Brachystele waldemarii (IOSPE WM) and Cyrtopodium izaguirreae (Phytotaxa), a palm Mangonia uruguaya (Jardín Botánico Montevideo), Xylosma schroederi (iNaturalist), Habranthus estensis and Habranthus versicolor (both at PBS), Euphorbia rochaensis (Flora Nativa de Uruguay), Tragia incana (Flora Nativa de Uruguay), Agalinis digitalis (iNaturalist), Hippeastrum harrisonii (Shields Gardens), Antiphytum charruasorum (Species New to Science), Mimosa magentea (Jardín Botánico Montevideo), Nothoscordum balaenense (Google Books), Acicarpha obtusisepala (Flora Nativa de Uruguay), Luzula ostenii (iNaturalist), Grindelia orientalis (flickr), Pfaffia ninae (iNaturalist), Zephyranthes estensis (fig. 4B at ResearchGate), Cypella alonsoana (Flora Nativa de Uruguay), Croton lombardianus (Flora Nativa de Uruguay), Oxalis monticola (iNaturalist), Porophyllum brevifolium (Flora Nativa de Uruguay), Baccharis rectialata and Baccharis funkiae (both at la diaria), Spergularia rupestris (iNaturalist), Diposis saniculaefolia (Flora Nativa de Uruguay), Oxypetalum marchesii (ResearchGate), and Hypericum cavernicola (iNaturalist).

Endemic mosses include Sphagnum herteri (GBIF), Anaschisma charrua (ResearchGate), and Physcomitrium herteri (GBIF).

The Uruguayan Savanna (EoE) is an important terrestrial ecoregion. Freshwater ecoregions include the Lower Uruguay (FEOW WM), the Lower Parana (FEOW WM), and the Laguna dos Patos (FEOW WM).