Adrianichthys Weber 1913

Adrianichthys Weber, 1913: 204–205 [type species: Adrianichthys kruyti Weber, 1913, by monotypy. Gender masculine].

Diagnosis: Adrianichthys is diagnosed as monophyletic by five unambiguous synapomorphies: paired or single preethmoid cartilage(s); orbits project somewhat beyond dorsal profile of head; premaxilla flat and broad with no distinct articular and ascending processes; maxilla relatively straight without dorsal process; and upper and lower jaw with two to four irregular rows of small, villiform teeth that form a pavement dentition. In addition, the ethmoid region of the skull is flat and broad, in lateral view, and there are no enlarged teeth posteriorly on the premaxilla, two characters also found in cyprinodontiforms, but not in ricefishes of the genus Oryzias.

Distribution and conservation status: The four species of Adrianichthys are endemic to Lake Poso, a tectonic, freshwater lake in Sulawesi Tengah with an area of 323 km 2 and a maximum depth of 450 m (Whitten, Mustafa & Henderson, 1987a: 255). The large ricefishes, or buntingi in the local vernacular, of Lake Poso and Lake Lindu are considered by Whitten et al. (1987a) to be endangered and some species possibly extinct, due in part to the introduction, at unknown dates, of exotic fish species such as tilapia, Oreochromis mossambicus, and common carp, Cyprinus carpio (see Whitten et al., 1987a; Groombridge, 1994; and the IUCN website, http://www.iucnredlist.org). Adrianichthys kruyti and A. poptae were considered nearly extinct or endangered by Soeroto & Tungka (1996). Field observations and collections by Kottelat (1990a: 64–65), Soeroto & Tungka (1996), Parenti & Soeroto (2004) and Parenti and colleagues in 1995 (reported in material examined below) support the contention that some Lake Poso ricefishes, once the basis of an important local fishery, are now rare, but not extinct. Adrianichthys oophorus, in particular, was abundant in 1995.