Porteresia coarctata (Roxb.) Tateoka is a true halophytic perennial wild grass that grows profusely along newly formed, highly saline landmasses and mudflats in the coastal mangroves of the Indian subcontinent and acts as a pioneer species in mangrove succession. Comprehensive phytolith analyses on sixteen P. coarctata samples collected from different swampy mangrove locations of four mangrove forests (Sundarbans, Bhitarkanika, Godavari and Krishna) along the Indian east coast show the significant and exclusive presence of a new specialized RONDEL having four distinct horns with flat base (named henceforth as RONDEL FOUR HORNED). Significant numbers of this morphotype have also been recorded in the surface sediment samples collected from these swampy mangrove sites. The RONDEL FOUR HORNED is a diagnostic phytolith morphotype of P. coarctata and a useful indicator of coastal swampy or intertidal mangroves of the Indian east coast. This morphotype was then used to identify past coastal intertidal mangrove environments in a late Quaternary sedimentary profile.

Porteresia coarctata (Roxb.) Tateoka 是一种真正的多年生盐生野草，在印度次大陆沿海红树林中新形成的高盐度陆地和泥滩上大量生长，是红树林演替中的先驱物种。16 种P. coarctata 的植硅体综合分析从印度东海岸的四个红树林（Sundarbans、Bhitarkanika、Godavari 和 Krishna）的不同沼泽红树林位置收集的样本表明，一种新的专业 RONDEL 具有重要而独特的存在，它具有四个不同的平底角（此后命名为 RONDEL FOUR HORNED ）。在从这些沼泽红树林地点收集的表层沉积物样本中也记录了大量这种形态类型。RONDEL 四角是P. coarctata的诊断植硅体形态类型，也是印度东海岸沿海沼泽或潮间带红树林的有用指标。然后使用这种形态类型来识别晚第四纪沉积剖面中过去的沿海潮间带红树林环境。