Ecological implications of molluscan ontogenetic strategies - examples from aquatic ecosystems of the Cenozoic Iberian Peninsula

Molluscs from marginal marine and intra-continental basins of the Iberian Peninsula are described with special emphasis on the early ontogenetic shell formation, which reflects the embryogenesis and larval ecology. The fossils, covering a time span from the Early Oligocene to the Early Pleistocene, are compared to contemporaneous fossil faunas of the Mediterranean and Paratethys, and to extant Mediterranean faunas. Larval shells occur in bivalves and gastropods of Upper Tortonian coastal lagoons near Crevillente (Alicante), indicating marine larval stages and a connection of the adult habitat with the open sea. The euryhaline marginal marine gastropods display planktotrophic larval shells, which enable a marine distribution, but prevented generally euryhaline genera, such as Granulolabium and Terebralia (Cerithioidea, Potamididae), from colonizing continental saline ecosystems. The establishment of athalassic saline populations implies the preadaptational loss of planktotrophy. For the first time lecithotrophic larval development in an athalassic saline system is documented for Potamides gaudryi (Cerithioidea, Potamididae) from the late Middle to early Upper Miocene of the Duero Basin. With regard to the early ontogenetic development, P. gaudryi is distinguished from its possible descendant, the extant Potamides conicus (Blainville, 1829), which represents a direct developer that lacks any larval stage. In comparison to direct development, lecithotrophic larval development was advantageous in the colonization of temporary habitats, such as flood areas. Two different modes of direct development with hatching of crawling young are documented: Feeding on embryonic yolk until the hatching stage and adelphophagy. Adelphophagous embryonic development appears to be advantageous in neritids, thiarids and pulmonates that live in habitats with strong predation of juvenile fishes based on the advanced developmental stage and larger shell size of the hatchlings.     

大尺度陆地生态系统状态变化及其资源环境效应的立体化协同联网观测

环境变化和人类活动的双重驱动正在快速地改变地球生态系统状态,呈现出了众多级联的资源环境问题,生态系统的状态变化和时空演变驱动因素以及相应的资源环境效应是大尺度陆地生态系统科学研究的永恒主题。观测和评估生态系统状态变化,发现和理解生态系统响应机制,认知和描述生态系统演变规律,预测和预警生态系统演变趋势,都依赖于大陆及全球尺度的分布式协同观测研究网络。本研究以服务大陆尺度生态系统科学研究、支撑区域生态环境治理为目标,围绕生态系统状态变化及资源环境效应科学问题,综合分析了现有生态环境观测研究网络现状,明确提出了生态系统观测研究站及其网络的发展方向,进而提出了发展“多要素-多界面-多介质-多过程-多尺度-多方法”的联网协同观测体系,构建“高新技术集成化-区域分布网络化-网络管理智能化-观测实验长期化-模型模拟多功能化-数据集成和资源共享远程化”的新一代大陆尺度生态系统观测实验研究网络的设想,并进一步阐述了该研究网络的功能定位、设计理念、设计方案、建设目标和技术体系,以期为我国陆地生态系统观测研究网络的发展提供借鉴与参考。     

The technical delimitation of a modern equidistant boundary

Abstract

Delimitation of maritime boundaries represents a recent state activity. The main impetus stems from the 1958 Geneva Conventions on the Territorial Sea … and on the Continental Shelf. State practice since 1958 has shown a marked preference for the equidistance principle for maritime boundary delimitation. At first many of these limits were geometrically constructed on existing nautical charts or on specifically designed small‐to medium‐scale maps. With increasing ability to exploit marine resources and the associated need to delimit boundaries farther from the baseline, inequities have developed as a consequence of map projections utilized, differences in horizontal and vertical datums, and so on. This paper discusses the principles behind, and the development of, conventional techniques of equidistant boundary delimitation; illustrates the errors that may result; and points out means, through modern computer technology, to compute equitable, equidistant maritime boundaries at great distances from the baselines.     

A Tribunal Navigating Complex Waters: Implications of the Bay of Bengal Case

The International Tribunal on the Law of the Sea's March 2012 Judgment in the Bay of Bengal Case is a landmark decision in multiple ways. It represents the first maritime boundary to be delimitated by the Tribunal. It is the first adjudication of a maritime boundary in Asia, and it is also the first judicial delimitation of a maritime boundary for parts of the extended continental shelf located seaward of the 200-nautical-mile limit from baselines. While the Tribunal's ruling largely resolves the maritime dispute between Bangladesh and Myanmar, it also raises a number of questions and concerns that are highlighted in this article, including the Tribunal's approach to delimitation both within and beyond the 200-nautical-mile limit, the treatment of islands, the interplay between law of the sea institutions and the creation of a so-called grey area where continental shelf jurisdiction falls to one state and water column jurisdiction to the other.     

南海西北部陆架区鱼类的种类组成与群落格局

根据2006-2007年在南海西北部陆架区海域进行的4航次底拖网调查数据,对该海域鱼类的种类组成和群落格局进行分析.调查共采获鱼类262种,隶属于20目102科.以冬季出现种类数最多,为166种;夏季和秋季次之,分别为161种和155种;春季最少,为135种.运用聚类分析和非度量多维标度(NMDS)方法分析了南海西北部陆架区鱼类群落结构的空间分布.研究表明,该海域鱼类可划分为5个群落,分别为粤西沿岸群落(群落Ⅰ)、海南岛东南沿岸群落(群落Ⅱ)、海南岛东部深海群落(群落Ⅲ)、过渡群落(群落Ⅳ)和混合群落(群落Ⅴ).ANOSIM检验表明,各群落间鱼类组成的差异极为显著(R=0.847-0.939,P＜0.001).鱼类群落格局的变化与海流和水深关系密切,有较明显的沿水深梯度分布的规律.咸淡水鱼类在雷州半岛东部的冷涡区域,形成群落Ⅰ;南海暖流控制区域内的深海鱼类,形成群落Ⅲ;在南海暖流最为强劲的冬季,研究区域内大部分鱼类集结为混合性群落Ⅴ;琼东南沿岸的上升流区内形成群落Ⅱ;沿岸流强劲的夏、秋季,在沿岸流和上升流交汇处,形成过渡性群落Ⅳ.     

Multivariate analysis of phyto-climatic patterns of the Croatian part of the eastern Adriatic coast

ABSTRACT

The present study analyses the climatic patterns of that part of the eastern Adriatic coast belonging to the Republic of Croatia and the narrow zone of the inlands. This area comprises a part of the Mediterranean phytogeographic region characterised by the Mediterranean climate type, and the transitional area towards the Eurosiberian phytogeographic region influenced by the continental climate type. The analysis was performed using multivariate numerical methods, cluster analysis following by the inertia analysis, and Principal Components Analysis with partitioning, considering the principal local climatic gradients in the data set. Six main climate classes were obtained. The results are biologically more interpretable than those obtained by using either numerical indices or the Walter climate diagram system. This suggests that multivariate numerical methods could be more efficient tools for detecting biologically significant climatic patterns on a small spatial scale.     

Extreme,continuous variation in an island snail: local diversification and association of shell form with the current environment

On Rosemary Island, a small continental island (11 km²) in the Dampier Archipelago, Western Australia, snails of the genus Rhagada have extremely diverse morphologies. Their shells vary remarkably in size and shape, with the latter ranging from globose to keeled‐flat, spanning the range of variation in the entire genus. Based primarily on variation in shell morphology, five distinct species are currently recognized. However, a study of 103 populations has revealed continuity of shell form within a very closely‐related group. A phylogenetic analysis of specimens from Rosemary Island, and other islands in the Dampier Archipelago, indicates that much of the morphological variation has evolved on the island, from within a monophyletic group. Within the island, snails with distinct shell morphologies could not be distinguished based on variation in mitochondrial DNA or their reproductive anatomy. The shell variation is geographically structured over a very fine scale, with clines linking the extreme forms over distances less than 200 m. Although there is no evidence that the different forms have evolved in isolation or as a consequence of drift, there is a strong association between keeled‐flat shells and rocky habitats, suggesting that shell shape may be of adaptive significance. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 104 , 756–769.     

Origin and in situ diversification in Hemidactylus geckos of the Socotra Archipelago

The Socotra Archipelago is an ancient continental fragment of Gondwanan origin and one of the most isolated landforms on Earth and a biodiversity hot spot. Yet, the biogeography and evolutionary history of its endemic fauna still remain largely overlooked. We investigate the origin, tempo and mode of diversification in the Hemidactylus geckos of the Socotra Archipelago. Concatenated and multilocus species coalescent analyses of Hemidactylus from Arabia and North Africa indicate that the Hemidactylus from Socotra do not form a monophyletic group and branch as three independent and well-supported clades instead. Both the chronogram inferred using the gene tree approach of BEAST and the age-calibrated multilocus species tree obtained using *BEAST suggest that the origin of Hemidactylus from Socotra may have involved a first vicariance event that occurred in the Early Miocene, followed by two independent transoceanic dispersal events that occurred more recently, during the Pliocene. Within Socotra, we analysed patterns of genetic diversity, the phylogeography and the demographic history in all seven nonintroduced species of Hemidactylus. Results based on two mitochondrial and two nuclear loci from 144 individuals revealed complex patterns of within-island diversification and high levels of intra-species genetic divergence. The interplay of both historical and ecological factors seems to have a role in the speciation process of this group of geckos. Interestingly, the case of H. forbesii and H. oxyrhinus, which inhabit the island of Abd al Kuri with an area of 133 km(2), may represent one of the most extreme cases of intra-island speciation in reptiles ever reported.     

Enzymatic polymorphisms in the Argentinian hake, Merluccius hubbsi Marini, of the Argentinian continental shelf

A survey described genetically encoded enzyme variation in 197 adult Argentinian hake, Merhccius hubhsi , collected from 10 sample sites on the Argentinian continental shelf. Four of 11 muscle enzyme loci were polymorphic ( PCM *, G3PDH *, EST-1 * and EST-2 *). Genotypes showed no significant difference between males and females. Only one of 37 tests of departure from Hardy-Weinberg equilibrium showed a significant difference. The allele frequency data were tested for genetic heterogeneity among locations. The overall significance of the total samples and among those from Patagonia Central was primarily due to heterogeneity at the EST-1 * locus. The implications of these findings in a population structure context are discussed.     

Species of Macrocyprina Triebel, 1960 (Crustacea, Ostracoda,Macrocyprididae) collected by the REVIZEE Program along Brazilian coast

Six samples collected from the eastern Brazilian continental shelf, along the states of Bahia and Espírito Santo, during the REVIZEE Program were analysed. Three species of Macrocyprina were encountered in these samples. Macrocyprina maddocksae sp. nov. is described. This species is diagnosed by the following combined characteristics: carapace fairly small, its lateral surface with three or four small subcircular patches, one small, subtriangular patch at anteroventral margin, one small, elongate, patch at posteroventral margin; male appendages V strongly asymmetrical, left appendage larger than right, podomere II of left appendage subtriangular, not recurved. Hemipenis subtrapezoidal. Furthermore, M. sp. nov. 3 Brandão, in press and M. sp. are recorded.