Re-evaluating Pleistocene-Holocene occupation of cave sites in north-west Thailand: New radiocarbon and luminescence dating

Established chronologies indicate a long-term 'Hoabinhian' hunter-gatherer occupation of Mainland Southeast Asia during the Terminal Pleistocene to Mid-Holocene (45 000-3000 years ago). Here, the authors re-examine the 'Hoabinhian' sequence from north-west Thailand using new radiocarbon and luminescence data from Spirit Cave, Steep Cliff Cave and Banyan Valley Cave. The results indicate that hunter-gatherers exploited this ecologically diverse region throughout the Terminal Pleistocene and the Pleistocene-Holocene transition, and into the period during which agricultural lifeways emerged in the Holocene. Hunter-gatherers did not abandon this highland region of Thailand during periods of environmental and socioeconomic change

Discovery of a silicate rock-boring organism and macrobioerosion in fresh water

Macrobioerosion is a common process in marine ecosystems. Many types of rock-boring organisms break down hard substrates, particularly carbonate rocks and calcareous structures such as dead corals and shells. In paleontology, the presence of rocks with boreholes and fossil macroboring assemblage members is one of the primary diagnostic features of shallow marine paleo-environments. Here we describe a silicate rock-boring organism and an associated community in submerged siltstone rock outcrops in Kaladan River, Myanmar. The rock-boring mussel Lignopholas fluminalis is a close relative of the marine piddocks, and its borings belong to the ichnospecies Gastrochaenolites anauchen. The neotectonic uplift of the area leading to gradual decrease of the sea level with subsequent shift from estuarine to freshwater environment was the most likely driver for the origin of this community. Our findings highlight that rocks with macroborings are not an exclusive indicator of marine paleo-ecosystems, but may also reflect freshwater habitats

Discovery of a silicate rock-boring organism and macrobioerosion in fresh water

International audienceMacrobioerosion is a common process in marine ecosystems. Many types of rock-boring organisms break down hard substrates, particularly carbonate rocks and calcareous structures such as dead corals and shells. In paleontology, the presence of rocks with boreholes and fossil macroboring assemblage members is one of the primary diagnostic features of shallow marine paleo-environments. Here we describe a silicate rock-boring organism and an associated community in submerged siltstone rock outcrops in Kaladan River, Myanmar. The rock-boring mussel Lignopholas fluminalis is a close relative of the marine piddocks, and its borings belong to the ichnospecies Gastrochaenolites anauchen. The neotectonic uplift of the area leading to gradual decrease of the sea level with subsequent shift from estuarine to freshwater environment was the most likely driver for the origin of this community. Our findings highlight that rocks with macroborings are not an exclusive indicator of marine paleo-ecosystems, but may also reflect freshwater habitats

Map of location of the field study areas.

<p>1—Kamchatka Peninsula (2012, I. Bolotov, Y. Bespalaya, I. Vikhrev, M. Gofarov), 2—Central Sakhalin (2012, same team), 3—southern Sakhalin (2011–2012, same team & Y. Kolosova, O. Aksenova), 4—Kunashir Island (2011, same team & Y. Kolosova, O. Aksenova), 5—Primorye (2012, same team), 6—Transbaikalia (2004–2011, O.K. Klishko). Data on the studied river sites are presented in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0122408#pone.0122408.s001" target="_blank">S1</a>–<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0122408#pone.0122408.s004" target="_blank">S4</a> Tables.</p

Shells of <i>Margaritifera dahurica</i> (Middendorff, 1850).

<p>A—Lectotype (ZISP: no. 7a). B—specimen from Komarovka River, Razdolnaya River basin, Primorye. Photos by I.V. Vikhrev. Scale bar—2 cm.</p

General plan of soft tissue of three Far Eastern margaritiferid species.

<p>A—<i>Margaritifera dahurica</i> (Middendorff, 1850). B—<i>M</i>. <i>laevis</i> (Haas, 1910). C—<i>M</i>. <i>middendorffi</i> (Rosén, 1926). Scale bar—1 cm.</p