Disappearance or overlooked or untouched? - A brief history of aquatic gastropods of Malaysian Borneo

The aquatic gastropods (marine and freshwater) in Malaysian Borneo (MYB) have an ancient history of 255 years, while the first record was observed in 1767 by the pioneer Carl Linnaeus. Over time, many European, native taxonomists and conservationists have worked on the diverse group of gastropods in the Malaysian part of Borneo (states of Sabah and Sarawak). No previous work has been conducted to assess the historical status of this particular class of Mollusca. The study objective was to reveal the types of aquatic gastropods and the number of published research and expeditions conducted in MYB. The bibliometric analysis found 145 research publications mentioning the names of the region and reporting at least one gastropod species from this geographic region. Over the history of 255 years, a total of 559 gastropod species were reported by different research groups. Between 1767 and 1900, a total of 150 gastropod species were reported, followed by 79 species from 1900 to 2000 and 330 species from 2001 to 2022. The Grubbs test (p<0.05) identified outlier years for the reporting of gastropod species from MYB with 54 new species each in 2011 and 2020 and 39 species in 2001. Over the history of aquatic gastropod research in MYB, the taxonomists making the greatest contribution were Han Raven and his colleagues from Naturalis Biodiversity Center, The Netherlands, The Netherlands, who reported 111 new species from the region, followed by Nur Leena Wong from Universiti Putra Malaysia (54 new species). The results suggested that reporting of new species from MYB is increasing, which may reflect the many unexplored sites and suggests the existence of as yet unrecorded species in this ecoregion. In this regard further expeditions and research should improve estimates of the true number of aquatic gastropod species in this area. These results can help the regional governments in making a regional biodiversity database as well as in taking decisions regarding aquatic gastropod research and management.