Taxonomic and taphonomic signatures of mollusk shell concentrations from coastal lagoon environments in Belize, Central America
Taxonomic and taphonomic signatures of mollusk shell concentrations from coastal lagoon environments in Belize, Central America
复制标题
中美洲伯利兹沿海泻湖环境中软体动物壳浓度的分类学和埋藏学特征
DOI：
10.1007/s10347-015-0454-4
复制
发表时间：
2016
期刊：
影响因子：
1.8
通讯作者：
Oschmann
中科院分区：
文献类型：
--
作者：
Adomat;Gischler;Oschmann
动物区系组成和分布模式的软体动物组合，从20壳浓度的核心收集在沿海泻湖，红树林的潮汐入口，和边缘海洋区（浅潮下带）沿着伯利兹中部海岸显示相当大的变化，由于环境的异质性和几个环境因素的相互作用的过程中，晚全新世（约2000年）。6000 cal BP至现代）。调查的≥2 mm动物群包括2246个双壳类、789个腹足类和11个舟足类标本。共鉴定出软体动物42科53种。优势种为双壳类、楔状异重虫和蟹足类，占总区系的78%.多样性指数低浓度从泻湖和相对较高的边缘海洋和潮汐入口地区。基于聚类分析和非度量多维标度，7泻湖组合和3个边缘海洋/潮汐入口组合的定义。泻湖和边缘的海洋/潮汐入口组合之间的分离，看到在排序表示泻湖-陆上梯度。泻湖组合之间的统计分离反映了全新世海岸泻湖演化过程中的环境变化，这可能与沙坝和沙嘴的形成有关。物种分布格局的控制因素很难排除，可能是由于障壁泻湖系统的异质性和古生态和古环境因素的相互作用。在分类学分析的基础上，对1827个A. cuneimeris从沿海泻湖进行。贝壳的埋藏深度、年龄与其埋藏条件无关。大小频率分布和左右瓣比率。cuneimersuggest认为，阀没有经过长距离的运输，而是准原地沉积在它们的原始栖息地。潮汐入口和边缘海洋环境中的贝壳也主要沉积在其原始栖息地。
Faunal composition and distribution patterns of mollusk assemblages from 20 shell concentrations in cores collected in coastal lagoons, a mangrove-fringed tidal inlet, and the marginal marine area (shallow subtidal) along the central coast of Belize show considerable variation due to environmental heterogeneity and the interplay of several environmental factors in the course of the mid-late Holocene (ca. 6000 cal BP to modern). The investigated fauna ≥2 mm comprises 2246 bivalve, 789 gastropod, and 11 scaphopod specimens. Fifty-three mollusk species, belonging to 42 families, were identified. The bivalveAnomalocardia cuneimerisand cerithid gastropods are the dominant species and account for 78 % of the total fauna. Diversity indices are low in concentrations from lagoons and relatively high in the marginal marine and tidal inlet areas. Based on cluster analysis and nonmetric multidimensional scaling, seven lagoonal assemblages and three marginal marine/tidal inlet assemblages were defined. A separation between lagoonal and marginal marine/tidal inlet assemblages seen in ordination indicates a lagoon-onshore gradient. The statistical separation among lagoonal assemblages demonstrates environmental changes during the Holocene evolution of the coastal lagoons, which is probably related to the formation of barriers and spits. The controlling factors of species distribution patterns are difficult to rule out, probably due to the heterogeneity of the barrier–lagoon systems and the interaction of paleoecological and paleoenvironmental factors. In addition to the taxonomic analysis, a taphonomic analysis of 1827 valves ofA. cuneimerisfrom coastal lagoons was carried out. There is no relationship between depth and age of shells and their taphonomic condition. Size-frequency distributions and right-left valve ratios ofA. cuneimerissuggest that valves were not transported over long distances but were deposited parautochthonously in their original habitat. Shells from tidal inlet and marginal marine environments were also predominantly deposited in their original habitats.