Late Miocene gastropods from northern Borneo (Brunei Darussalam, Seria Formation)

Author(s): Mathias Harzhauser, Han Raven, Bernard M. Landau, Laszlo Kocsis, Asiqqin Adnan, Martin Zuschin, Oleg Mandic, Antonino Briguglio
Abstract: We present the first systematic description of a Tortonian (late Miocene) gastropod assemblage from the Ambug Hill section in
the Tutong District in Brunei Darussalam. The low-diversity assemblage comprises 62 species of which 37 are unknown from other
Neogene faunas of the Indo-West Pacific Region (IWP), 23 species are formally described as new. Carnivorous, scavenging and detritus
feeding species predominate and the ecological requirements of extant relatives suggest a mud-bottom environment of the inner shelf
in several tens of meters water depth with reduced vegetation. The small size of most specimens, the frequent occurrence of subadult
shells and small size of several species relative to congeneric species might point to suboptimal environmental conditions during the
deposition of this part of the Seria Formation. The very low relations with Neogene gastropod faunas from Indonesia at species level
might be explained by the biogeographic isolation between the faunas of the Java and Celebes seas and that from the South China Sea.
A severe undersampling and rather spotty taxonomic descriptions of Neogene IWP-faunas and a lack of assemblages from identical
depositional environments from Indonesia may also contribute to the seemingly endemic character of the Ambug Hill fauna.
Rhinoclavis pulcherrima n. sp., Rissoina tutongensis n. sp., Ficus parvissima n. sp., Dolomena bruneiensis n. sp., Scalptia verheckeni n. sp.,
Phos bruneiensis n. sp., Nassarius pseudoovum n. sp., Indomitrella acuticonica n. sp., Hemifusus charlieleei n. sp., Prunum seriaense n. sp.,
Cymbiola ambugensis n. sp., Ziba waltercernohorskyi n. sp., Amalda bruneiana n. sp., Tomopleura furcata n. sp., Unedogemmula nuttalli
n. sp., Gemmula sculpturata n. sp., Crassispira strangulata n. sp., Paradrillia pachyspira n. sp., Conasprella paupera n. sp., Conasprella
trianginodus n. sp., Triplostephanus wilfordi n. sp., Duplicaria aequalis n. sp. and Architectonica beetsi n. sp. are established as new
species.
Organisation(s): Department of Palaeontology
External organisation(s): Universiti Brunei Darussalam (UBD), Naturhistorisches Museum Wien (NHM), Naturalis Biodiversity Center, Universidade de Lisboa
Journal: Palaeontographica. Abt. A: Palaeozoologie - Stratigraphie
Volume: 313
Pages: 1-79
No. of pages: 79
ISSN: 0375-0442
Publication date: 2018
Peer reviewed: Yes
Austrian Fields of Science 2012: 105118 Palaeontology
Portal url: https://ucrisportal.univie.ac.at/en/publications/5e90a99c-516f-4dbc-9b1c-4e66223c8bcf

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