Pérez Liseth, Lorenschat Julia, Brenner Mark, Scharf Burkhard, Schwalb Antje
Institute of Environmental Geology, University of Braunschweig, Langer Kamp 19c, 38106, Braunschweig, Germany.
Rev Biol Trop. 2010 Sep;58(3):871-95. doi: 10.15517/rbt.v58i2.5252.
Ostracode taxonomy has been of great interest because of their possible use as indicator species in climate and ecosystem changes. In Central and South America, few studies have been carried out and this study includes a contribution to the group. Eleven ostracode species were collected in Lago Petén Itzá (approximately 100km2), the second largest lowland lake in Guatemala, and from its inflow tributary, Río Ixlú in November 2005 and February 2008. Twenty-seven surface sediment samples were retrieved at water depths from the littoral zone to the lake's maximum depth (>160m). Hard and soft parts of ostracodes were analyzed, and each ostracode species was described for taxonomy, size, ecology, biology and geographic distribution. Species recorded include: Candonocypris serratomarginata?, Cypretta brevisaepta?, Cypridopsis okeechobei, Cytheridella ilosvayi, Darwinula stevensoni, Heterocypris punctata, Limnocythere opesta, Physocypria globula, Pseudocandona sp., Stenocypris major and Strandesia intrepida. Most of the species have a neotropical distribution, two are distributed world-wide (D. stevensoni and S. major), and C. okeechobei and P. globula display nearctic and neotropical distributions. We present new records of C. brevisaepta?, C. serratomarginata?, S. major, and S. intrepida in Guatemala. Physocypria globula was misidentified previously in Lago Petén Itzá as Cypria petenensis, Pseudocandona sp. was misidentified as Candona sp., and C. okeechobei was identified the past as C. vidua. Limnocythere opesta is the only endemic species of the Petén Lake District, Guatemala. The most abundant and widely distributed species in the lake are P. globula, C. okeechobei, and Pseudocandona sp. Species restricted to the littoral zones and water depths <15 m are C. brevisaepta?, D. stevensoni, H. punctata, and S. intrepida. Limnocythere opesta, C. ilosvayi, C. okeechobei, and Pseudocandona sp. are distributed from the littoral zone to a depth of 40m. Species collected only in the Ixlú tributary and in a littoral zone on the west side of the lake were C. serratomarginata? and S. major. During November, live adult L. opesta and C. okeechobei were abundant, but no C. brevisaepta? or C. serratomarginata? adults were found. Adult specimens of C. ilosvayi were more abundant in February. In general, ostracodes collected were smaller than those reported in the literature. An accurate taxonomy will improve the use of ostracode fossil assemblages in long sediment cores when reconstructing past climatic and environmental changes in the northern lowland Neotropics.
由于介形虫有可能被用作气候和生态系统变化的指示物种，其分类学一直备受关注。在中美洲和南美洲，相关研究较少，而本研究为该类群做出了贡献。2005年11月和2008年2月，在危地马拉第二大低地湖泊佩滕伊察湖（面积约100平方公里）及其流入支流伊克卢河采集到了11种介形虫。在从湖滨带到湖泊最大深度（>160米）的不同水深位置采集了27个表层沉积物样本。对介形虫的硬体和软体部分进行了分析，并对每种介形虫的分类学、大小、生态、生物学和地理分布进行了描述。记录的物种包括：锯齿缘坎多介？、短肋塞普介？、奥基乔比丽星介、伊洛瓦伊小浪花介、史蒂文森达尔文介、斑点异星介、奥佩斯塔湖花介、球形泡状介、伪坎多介属、大窄背介和无畏斯特兰介。大多数物种分布于新热带区，有两种分布在全球（史蒂文森达尔文介和大窄背介），奥基乔比丽星介和球形泡状介显示出近北区和新热带区的分布。我们给出了危地马拉短肋塞普介？、锯齿缘坎多介？、大窄背介和无畏斯特兰介的新记录。球形泡状介先前在佩滕伊察湖被误鉴定为佩滕塞普介，伪坎多介属被误鉴定为坎多介属，奥基乔比丽星介过去被鉴定为维杜丽星介。奥佩斯塔湖花介是危地马拉佩滕湖区唯一的特有物种。湖中数量最多、分布最广的物种是球形泡状介、奥基乔比丽星介和伪坎多介属。局限于湖滨带和水深<15米的物种有短肋塞普介？、史蒂文森达尔文介、斑点异星介和无畏斯特兰介。奥佩斯塔湖花介、伊洛瓦伊小浪花介、奥基乔比丽星介和伪坎多介属分布于湖滨带到40米深处。仅在伊克卢支流和湖西侧湖滨带采集到的物种是锯齿缘坎多介？和大窄背介。11月期间，成年奥佩斯塔湖花介和奥基乔比丽星介数量众多，但未发现短肋塞普介？或锯齿缘坎多介？的成虫。2月，伊洛瓦伊小浪花介的成年标本更为丰富。总体而言，采集到的介形虫比文献报道的要小。准确的分类学将有助于在重建新热带区北部低地过去的气候和环境变化时，更好地利用长沉积岩芯中的介形虫化石组合。
