Cypriniformes of Borneo (Actinopterygii, Otophysi): An Extraordinary Fauna for Integrated Studies on Diversity, Systematics, Evolution, Ecology, and Conservation

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Borneo Island is governed by the countries of Brunei Darussalam, Malaysia (Sabah and Sarawak) and Indonesia(Kalimantan) and is part of Sundaland. These countries have a high diversity of freshwater fishes, especially describedand undescribed species of Cypriniformes; together these species and other flora and fauna represent an extraordinaryopportunity for worldwide collaboration to investigate the biodiversity, conservation, management and evolution ofBorneo’s wildlife. Much of the fauna and flora of Borneo is under significant threat, warranting an immediate and swiftinternational collaboration to rapidly inventory, describe, and conserve the diversity. The Sunda drainage appears to havebeen an important evolutionary centre for many fish groups, including cypriniforms (Cyprinidae, Balitoridae andGyrinocheilidae); however, Northwestern Borneo (Brunei, Sabah and Sarawak) is not connected to Sundaland, and thisdisjunction likely explains the non-homogeneity of Bornean ichthyofauna. A previous study confirmed that northernBorneo, eastern Borneo and Sarawak shared a similar ichthyofauna, findings that support the general hypothesis forfreshwater connections at one time between western Borneo and central Sumatra, and south Borneo and Java island.Borneo is drained by five major rivers: (1) Rajang and Baram rivers in Sarawak, and (2) Kapuas, Mahakam and Baritorivers in Kalimantan. The Cypriniformes is the most diverse clade in Borneo, and it is represented by at least 285 speciesin 55 genera and eight major clades (Balitoridae, Cobitidae, Cyprinidae, Gyrinocheilidae, Leptobarbidae, rasborines,cultrines and Paedocyprididae); at least 147 (52%) of these species are endemic to the incredibly diverse habitats ofBorneo. Most fish faunal studies in Borneo have involved inventory and discovery; however, none to date have focusedtheir efforts on the great biodiversity and systematics of Cypriniformes. In this paper we briefly discuss the generalbiodiversity of cypriniforms in Borneo, including recent revisions to the classification of the order through theCypriniformes Tree of Life and Planetary Biodiversity Inventory efforts supported by the USA NSF basic scienceinitiatives, in conjunction with researchers in countries of Borneo. It is our hope that this particular summary willgalvanize individuals to increase worldwide collaborative and integrated efforts on the biodiversity of Cypriniformes,and incite lively discussions among a broad array of interested parties, including those involved in the recent and critically important “Heart of Borneo” initiative funded by all these countries and some NGOs.