species that have been described by science lack adequate information
on where they originally came from. These species names are
based on a single specimen, in some cases subsequently lost, which may
or may not be valid species.
Some locality data attached to certain specimens appear to taxonomists to be almost certainly wrong. The caecilian Caecilia mertensi (BHL) seems much more likely to have originated from somewhere in South America instead of the Seychelles. Jan's Snake Elapotinus picteti (fig. 1 at BHL) is the sole member of its genus and after long debate as to whether it originated in French Guiana or somewhere in Africa has recently been determined to be identical to a snake described over a century later in Madagascar (Serpent Research). Similar cases are provided by Temminck’s Mysterious Bat Nycticeius aenobarbus (Mammal Species of the World) and the Dubious Trumpet-eared Bat Phoniscus aerosa (Mammal Species of the World) (Internet Archive).
Sharpe's Rail Gallirallus sharpei (Naturalis) is known from a single specimen but is now believed to be merely a color morph of the Buff-banded Rail Gallirallus philippensis. Hornby's Storm-petrel Oceanodroma hornbyi (Wikipedia) is well known at sea, but its breeding grounds remain a mystery.
Reptile species of uncertain origin include a ground snake Liophis leucogaster (fig. 1 at BHL), the Mystery Worm Snake Typhlops disparilis (fig. 6 at BHL), the Equator Tree Snake Sibynomorphus inaequifasciatus (fig. 2 at BHL), the Three-lined Centipede Snake Tantilla trilineata (fig. 2 at BHL), and the Small-lipped Galliwasp Diploglossus microlepis (fig. 2 at BHL).
Amphibian species of questionable origin include a tree frog Hyla auraria (SysTax), a rhacophorid Dendrobatorana (or Hylambates) dorsalis (fig. 5 at BHL), a reed frog Hyperolius thoracotuberculatus (SysTax), a caecilian Ichthyophis humphreyi (BHL), and the Turkestanian Salamander Hynobius turkestanicus (CI).
Freshwater fish of unclear origin include a catfish Pimelodella rendahli (ACSI) from somewhere in South America and a tetra Hyphessobrycon melasemeion (FishBase) that may be from the lower Amazon.
Plant genera of unknown origin include Sericospora crinita (JSTOR) from somewhere in the West Indies and Menais topiaria (Real Jardín Botánico pdf file) from South America.