Topic
Lepidurus
About: Lepidurus is a research topic. Over the lifetime, 36 publications have been published within this topic receiving 704 citations.
Papers
TL;DR: remains of pelagic species, but also of Lepidurus and some benthic chydorids, may be used to detect changes in fish abundance and predation pressure in the past and may be useful for detecting the impact of past climate change on top-down control by fish.
Abstract: We studied the trophic structure in the pelagial and crustacean remains in the surface 1 cm of the sediment of 13 shallow, high arctic lakes in northeast Greenland (74° N). Seven lakes were fishless, while the remaining six hosted a dwarf form of Arctic charr (Salvelinus alpinus). In fishless lakes, Daphnia pulex was abundant, while no daphnids were found in the pelagial of lakes with fish. In fish lakes, the zooplankton community was dominated numerically by cyclopoid copepods and rotifers. Both lake sampling and analysis of remains in the top 1 cm of the sediment indicated that the phyllopod, Lepidurus arcticus, occurred in all fishless lakes, but was either absent or present in low densities from lakes with fish. Adult Lepidurus are mainly predators and forage in the top layer of the sediment. An analysis of surface sediment revealed low abundance of the benthic chydorids Alona sp. and Macrothrix sp. in lakes with Lepidurus, while they were abundant in lakes with fish. The low abundance in fishless lakes could not be explained by damage of crustacean remains caused by Lepidurus feeding in the sediment, because remains of the more soft-shelled, pelagic-living Daphnia were abundant in the sediment of these lakes. No significant differences between lakes with and without fish were found in chlorophyll a, total phosphorus, total nitrogen, conductivity or temperature, suggesting that the observed link between Lepidurus arcticus and the benthic crustacean community is causal. Consequently, remains of crustaceans in high arctic lake sediments may be useful for detecting the impact of past climate change on top-down control by fish. Not only remains of pelagic species, but also of Lepidurus and some benthic chydorids, may be used to detect changes in fish abundance and predation pressure in the past.
79 citations
TL;DR: The results confirm the monophyly of both extant notostracan genera Triops and Lepidurus with good support in model based and maximum parsimony analyses and form a biogeographic hypothesis that explains distributions of extant lineages predominantly by overland dispersal routes.
65 citations
TL;DR: A molecular phylogeny of the Notostraca was constructed using model based phylogenetic methods and it was concluded that, although some present day tadpole shrimp species closely resemble fossil specimens as old as 250 mya, no molecular support was found for an ancient (pre) Mesozoic radiation.
Abstract: Tadpole shrimp (Crustacea, Notostraca) are iconic inhabitants of temporary aquatic habitats worldwide. Often cited as prime examples of evolutionary stasis, surviving representatives closely resemble fossils older than 200 mya, suggestive of an ancient origin. Despite significant interest in the group as ‘living fossils’ the taxonomy of surviving taxa is still under debate and both the phylogenetic relationships among different lineages and the timing of diversification remain unclear. We constructed a molecular phylogeny of the Notostraca using model based phylogenetic methods. Our analyses supported the monophyly of the two genera Triops and Lepidurus, although for Triops support was weak. Results also revealed high levels of cryptic diversity as well as a peculiar biogeographic link between Australia and North America presumably mediated by historic long distance dispersal. We concluded that, although some present day tadpole shrimp species closely resemble fossil specimens as old as 250 mya, no molecular support was found for an ancient (pre) Mesozoic radiation. Instead, living tadpole shrimp are most likely the result of a relatively recent radiation in the Cenozoic era and close resemblances between recent and fossil taxa are probably the result of the highly conserved general morphology in this group and of homoplasy.
65 citations
TL;DR: The results suggest at least two bouts of global radiation in Notostraca, one of them recent, so questioning the validity of the ‘living fossils’ concept in groups where cryptic speciation is widespread is questioned.
Abstract: ‘Living fossils’, a phrase first coined by Darwin, are defined as species with limited recent diversification and high morphological stasis over long periods of evolutionary time. Morphological stasis, however, can potentially lead to diversification rates being underestimated. Notostraca, or tadpole shrimps, is an ancient, globally distributed order of branchiopod crustaceans regarded as ‘living fossils’ because their rich fossil record dates back to the early Devonian and their morphology is highly conserved. Recent phylogenetic reconstructions have shown a strong biogeographic signal, suggesting diversification due to continental breakup, and widespread cryptic speciation. However, morphological conservatism makes it difficult to place fossil taxa in a phylogenetic context. Here we reveal for the first time the timing and tempo of tadpole shrimp diversification by inferring a robust multilocus phylogeny of Branchiopoda and applying Bayesian divergence dating techniques using reliable fossil calibrations external to Notostraca. Our results suggest at least two bouts of global radiation in Notostraca, one of them recent, so questioning the validity of the ‘living fossils’ concept in groups where cryptic speciation is widespread.
50 citations
1 Jan 2006
TL;DR: The comparison of the genetic distances between these samples and those found among other species of Notostraca strongly suggests that the three Triops granarius populations investigated belong to different, possibly cryptic species.
Abstract: We used three ribosomal DNA markers to investigate the genetic divergence of Triops granarius (Lucas, 1864) populations from Tunisia, Namibia and Japan. The comparison of the genetic distances between these samples and those found among other species of Notostraca (both Triops and Lepidurus) strongly suggests that the three Triops granarius populations investigated belong to different, possibly cryptic species.
35 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2021 | 1 |
| 2019 | 3 |
| 2017 | 1 |
| 2013 | 2 |
| 2012 | 3 |
| 2011 | 1 |