''Xixiaichthys'' is an extinct genus of

osteoglossiform Osteoglossiformes , meaning "bony tongues" in Ancient Greek, is a relatively primitive order (biology), order of ray-finned fish that contains two sub-orders, the Osteoglossoidei and the Notopteroidei. All of at least 245 living species inhabit f ...

fish that lived in

China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...

during the

Early Cretaceous The Early Cretaceous (geochronology, geochronological name) or the Lower Cretaceous (chronostratigraphy, chronostratigraphic name) is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 143.1 ...

and was found in the Madongshan Formation and also the

Xinminbao Group The Xīnmínbǎo Group () is a group of geological formations in north central China. They occur across a large depression between the Altai Mountains of Mongolia to the north and the Qilian mountains of the Qinghai Plateau to the south, in the ...

. The type species is ''Xixiaichthys tongxiensis'' and is based on the

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

(specimen V 13114.1), a complete skeleton,Zhang, J. (2004). New Fossil Osteoglossomorph from Ningxia, China. ''Journal of Vertebrate Paleontology'' 24(3):515-524 and several other specimens of varying completeness. Kim ''et al.'' (2022) compared a fish centrum found with the

of the

theropod Theropoda (; from ancient Greek , (''therion'') "wild beast"; , (''pous, podos'') "foot"">wiktionary:ποδός"> (''pous, podos'') "foot" is one of the three major groups (clades) of dinosaurs, alongside Ornithischia and Sauropodom ...

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic Geological period, period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the #Evolutio ...

Raptorex ''Raptorex'' is a genus of tyrannosaurid dinosaur. Its fossil remains consist of a single juvenile specimen probably uncovered in Mongolia, or possibly northeastern China. The type species is ''R. kriegsteini'', described in 2009 by Sereno and ...

kriegsteini'' with ''

Harenaichthys ''Harenaichthys'' is an extinct genus of osteoglossiform fish that lived in Mongolia during the Late Cretaceous and was found in the Nemegt Formation. The type species is ''H. lui'' and is based solely on the holotype, which consists of partial ...

lui'' and ''Xixiaichthys tongxinensis'', and interpreted their findings as supporting the conclusion that the holotype of ''R. kriegsteini'' comes from the Nemegt Formation. They also tentatively assigned the centrum to their new genus ''Harenaichthys''.

References

{{Taxonbar, from=Q113381481 Fossil taxa described in 2004 Prehistoric ray-finned fish genera