MOLECULAR CLOCK AND PALEOBIOGEOGRAFI OF GENUS TROCHUS AND ITS RELATION WITH SEA LEVEL CHANGES AFTER 21.000 BP IN SUNDA SHELF

• Main Author: Gathot Harbowo, Danni
• Format: Theses
• Language: Indonesia
• Subjects: Geologi, hidrologi & meteorologi
• Online Access: https://digilib.itb.ac.id/gdl/view/34383
• Institution: Institut Teknologi Bandung

Global sea level rise after the last glacial maximum (21.000 BP) in Sunda Shelf is an interesting phenomenon to be understood further. There are a lot of changes in the geography of the Sunda Shelf in time, including biogeography and distribution dynamics of fauna and flora. In this study, we aim to observe several changes of the paleobiogeography that caused by global sea-level changes, post Last Glacial Maximum (LGM) from gene COI in mtDNA of genus Trochus. Data accuired from field sampling and some from collecting data in Genbank database. We combined two methods which by analyzing the phylogenetic tree from mtDNA with molecular clock method using MEGA v5.0 which combined with paleogeography maps, in process with GEBCO 0.8-grid with 30 arc-second resolution by Surfer v10.3. We used a specific group of marine animals that live in the intertidal area, i.e. genus Trochus. We gained that there are two origin of Trochus ancestral, i.e. Sunda Shelf origin (13.700 ± 1.280 BP.) and Sahul Shelf origin (8.400 ± 1.100 BP.), which diverge in four mayor of distribution pathway, i.e. (1) Java Sea Pathway when sea level -72,0 m, coincidence with Meltwater pulse 1A and Older Dryas (13.700 ± 1.280 BP); (2) Karimata Strait Pathway, coincidence with Younger Dryas and Meltwater pulse 1B (began at 11.200 ± 1.420 BP) when sea level -45,0 m; (3) Sunda Strait Pathway which coincidence with many island isolation in Sunda Shelf (8.400 ± 1.100 to 6.900 ± 1.340 BP) which sea level -21,5 m; (4) Nusa Tenggara Pathway, which coincidence with Mid-Holocene Highstand (3.800 ± 530 to 3.500 ± 490 BP) with sea level at +4,4 m. We suspect, Trochus speciation, occurs along in their distribution pathway and is more due by environmental changes such as changes in aquatic conditions and shifting in global climatic conditions at the time.