We report here diverse Late Miocene fish assemblages based on otoliths collected from sedimentary rocks deposited in coastal marine settings in northern Borneo (Seria and Miri formations and Tutong beach). Surface-collected, large-sized otoliths, representing > 96% of the whole assemblage, are dominated by the families Sciaenidae and Ariidae, while Haemulidae, Engraulidae, and Lactaridae can be common at certain sites. Additional taxa were revealed by screen-washing of the sediments from selected sites including taxa from the families of Congridae, Bregmacerotidae, Apogonidae, Gobidae, Sillaginidae, and Cepolidae. Among the sciaenids, we describe six new taxa (Advenasciaena bruneiana, Atrobucca borneensis, Bruneisciaena schwarzhansi, Nibea ambugensis, Nibea stintoni, and Protonibea nolfi), and we also report the first fossil occurrence of some other groups (e.g. Lactarius lactarius, Acanthocepola sp.) from the Indo-Australian Archipelago (IAA). All these discoveries add to our understanding of fish palaeobiodiversity in the IAA where today’s highest marine biodiversity exists. The compositions of the faunas reflect a shallow marine coastal palaeoenvironment with close connection to estuaries where some of the reported fishes might have migrated seasonally or daily with the tide. Turbid, suspension-loaded water might be also presumed, where ariids, sciaenids, and the haemulid Pomadasys are often observed today. ZooBank LSID for the described genera: Advenasciaenazoobank.org:act:5D6D3223-462F-4488-88BE-8DDDB107BFB6 Bruneisciaenaurn:lsid:zoobank.org:act: 090DAD2F-FB18-43CB-9CA9-5F9FE224CA54 ZooBank LSID for the described species: Advenasciaena bruneianaurn:lsid:zoobank.org:act: D14930B9-5847-4A1F-9D20-EFC0501F3B3D Atrobucca borneensisurn:lsid:zoobank.org:act: 36E0F8EC-0266-4BBB-B00A-B43C1B1C7557 Bruneisciaena schwarzhansiurn:lsid:zoobank.org:act: B9B2F637-CC09-44A3-AEE6-6C8EE76FBE34 Nibea ambugensisurn:lsid:zoobank.org:act: 8C780272-A910-404D-89FA-C0BB110B9CEF Nibea stintoniurn:lsid:zoobank.org:act: 8D750E35-8BD4-481A-822D-7F4DA3816E04 Protonibea nolfiurn:lsid:zoobank.org:act: 81BC0700-50E1-400B-9034-F83DDA6C7710

We report here diverse Late Miocene fish assemblages based on otoliths collected from sedimentary rocks deposited in coastal marine settings in northern Borneo (Seria and Miri formations and Tutong beach). Surface-collected, large-sized otoliths, representing > 96% of the whole assemblage, are dominated by the families Sciaenidae and Ariidae, while Haemulidae, Engraulidae, and Lactaridae can be common at certain sites. Additional taxa were revealed by screen-washing of the sediments from selected sites including taxa from the families of Congridae, Bregmacerotidae, Apogonidae, Gobidae, Sillaginidae, and Cepolidae. Among the sciaenids, we describe six new taxa (Advenasciaena bruneiana, Atrobucca borneensis, Bruneisciaena schwarzhansi, Nibea ambugensis, Nibea stintoni, and Protonibea nolfi), and we also report the first fossil occurrence of some other groups (e.g. Lactarius lactarius, Acanthocepola sp.) from the Indo-Australian Archipelago (IAA). All these discoveries add to our understanding of fish palaeobiodiversity in the IAA where today’s highest marine biodiversity exists. The compositions of the faunas reflect a shallow marine coastal palaeoenvironment with close connection to estuaries where some of the reported fishes might have migrated seasonally or daily with the tide. Turbid, suspension-loaded water might be also presumed, where ariids, sciaenids, and the haemulid Pomadasys are often observed today. ZooBank LSID for the described genera: Advenasciaenazoobank.org:act:5D6D3223-462F-4488-88BE-8DDDB107BFB6 Bruneisciaenaurn:lsid:zoobank.org:act: 090DAD2F-FB18-43CB-9CA9-5F9FE224CA54 ZooBank LSID for the described species: Advenasciaena bruneianaurn:lsid:zoobank.org:act: D14930B9-5847-4A1F-9D20-EFC0501F3B3D Atrobucca borneensisurn:lsid:zoobank.org:act: 36E0F8EC-0266-4BBB-B00A-B43C1B1C7557 Bruneisciaena schwarzhansiurn:lsid:zoobank.org:act: B9B2F637-CC09-44A3-AEE6-6C8EE76FBE34 Nibea ambugensisurn:lsid:zoobank.org:act: 8C780272-A910-404D-89FA-C0BB110B9CEF Nibea stintoniurn:lsid:zoobank.org:act: 8D750E35-8BD4-481A-822D-7F4DA3816E04 Protonibea nolfiurn:lsid:zoobank.org:act: 81BC0700-50E1-400B-9034-F83DDA6C7710

The sand pit of Pécs-Danitzpuszta is one of the most important mixed Neogene vertebrate localities in Hungary, with older Miocene (Langhian – Serravallian) terrestrial and marine animal remains re-deposited into the upper Miocene (Tortonian) Lake Pannon sediments. Due to the mixed status of the Pécs-Danitzpuszta vertebrate assemblages, limited information is available about the former depositional environment and age of these fossils. However, the rare earth element (REE) composition of the fossil apatite can help to determine the stratigraphic origin and the early depositional environments of unprovenanced vertebrate remains. In this study, the REE composition of more than 60 vertebrate fossils, among them reworked and in situ remains from the Mecsek Mountain, were analysed. The results allowed separation between the Badenian, Sarmatian, and Pannonian aged fossils. The REE content and their distribution also helped us characterise the ancient depositional conditions of the investigated reworked fossils. Furthermore, several different types of vertebrate fossils were analysed, resulting in a large database that helped clarify the likely timings and mechanisms of REE uptake at this locality. Apparent variation in REE chemistry within bones (cortical vs cancellous) and teeth (enamel vs dentine) are best linked to fractionation along the REE series during their incorporation.

The sand pit of Pécs-Danitzpuszta is one of the most important mixed Neogene vertebrate localities in Hungary, with older Miocene (Langhian – Serravallian) terrestrial and marine animal remains re-deposited into the upper Miocene (Tortonian) Lake Pannon sediments. Due to the mixed status of the Pécs-Danitzpuszta vertebrate assemblages, limited information is available about the former depositional environment and age of these fossils. However, the rare earth element (REE) composition of the fossil apatite can help to determine the stratigraphic origin and the early depositional environments of unprovenanced vertebrate remains. In this study, the REE composition of more than 60 vertebrate fossils, among them reworked and in situ remains from the Mecsek Mountain, were analysed. The results allowed separation between the Badenian, Sarmatian, and Pannonian aged fossils. The REE content and their distribution also helped us characterise the ancient depositional conditions of the investigated reworked fossils. Furthermore, several different types of vertebrate fossils were analysed, resulting in a large database that helped clarify the likely timings and mechanisms of REE uptake at this locality. Apparent variation in REE chemistry within bones (cortical vs cancellous) and teeth (enamel vs dentine) are best linked to fractionation along the REE series during their incorporation.

We report on sporadic fossil vertebrates from Brunei Darussalam (Borneo). Most of these isolated remains are reworked and derive from Penanjong Beach known for former coastal cliffs used to be rich in marine molluscs. Previously, the only vertebrate remains reported were shark teeth. With new material, the fish fauna is now represented by six shark and a single ray taxa, while remains of three turtle families were discovered (Trionychidae, Cheloniidae, Geoemydidae). This fauna is compared to nearby upper Miocene fossiliferous beds from where remains of cheloniid and trionychid turtles were unearthed. To assess the origin of the reworked remains, rare earth element (REE) concentrations of the fossil bioapatite were compared between the reworked and the geographically closest in-situ Ambug Hill fauna. The obtained trend in REE variations are identical, revealing similar REE uptake mechanism and early diagenetic conditions. With the additional fact that the succession outcropping at Ambug Hill cuts the coastline imply that the majority of the reworked fossils derive from the local Miocene beds. This is supported by Sr-isotope ages from reworked calcite bivalve shells ranging from 9.74 to 6.62 Ma. These turtle remains thus represent the hitherto known first Neogene fossil tetrapods from Borneo.

We report on sporadic fossil vertebrates from Brunei Darussalam (Borneo). Most of these isolated remains are reworked and derive from Penanjong Beach known for former coastal cliffs used to be rich in marine molluscs. Previously, the only vertebrate remains reported were shark teeth. With new material, the fish fauna is now represented by six shark and a single ray taxa, while remains of three turtle families were discovered (Trionychidae, Cheloniidae, Geoemydidae). This fauna is compared to nearby upper Miocene fossiliferous beds from where remains of cheloniid and trionychid turtles were unearthed. To assess the origin of the reworked remains, rare earth element (REE) concentrations of the fossil bioapatite were compared between the reworked and the geographically closest in-situ Ambug Hill fauna. The obtained trend in REE variations are identical, revealing similar REE uptake mechanism and early diagenetic conditions. With the additional fact that the succession outcropping at Ambug Hill cuts the coastline imply that the majority of the reworked fossils derive from the local Miocene beds. This is supported by Sr-isotope ages from reworked calcite bivalve shells ranging from 9.74 to 6.62 Ma. These turtle remains thus represent the hitherto known first Neogene fossil tetrapods from Borneo.