Specimens of a new species, Elaphoidella sanoamuangae n. sp., were collected during an investigation of cave-dwelling copepods in a tourist cave in the Phuket mountain range, South Thailand, and the ...new species is described and depicted herein. Elaphoidella sanoamuangae n. sp. fits into Elaphoidella group VII sensu Lang (1948). The new species is most similar to E. schubarti Chappuis, 1936. The differential characters for females of the two species are: (a) the free margin of the anal operculum, (b) the number of ventral spinules on the anal somite, (c) the shape of the caudal rami, (d) the shape of the inner terminal caudal seta, (e) the segmentation of Endp P1, (f) the armature formula of Endp-2 P2-P4, and (g) the size of the setae on P5.
Maraenobiotus slovenicus sp. nov. is described from subterranean waters of a very cold, temporary karstic spring in the vicinity of Velika Pasica cave, central Slovenia. A detailed examination of ...numerous specimens reveals a low level of morphological variability in this population. Morphological characters traditionally used in the genus Maraenobiotus Mrázek, 1893 would identify our population as a subspecies of the polymorphic and widely distributed M. vejdovskyi Mrázek, 1893. This species was reported from the Palearctic, with at least six accepted subspecies, some of which have been reported in sympatry or parapatry, sometimes even without any apparent niche partitioning. One of these subspecies, M. vejdovskyi truncatus Gurney, 1932, originally described from the UK and later on also reported from Italy and Japan, shares with our population the extremely reduced female principal caudal setae. However, a closer examination of the caudal armature and other characters reveals significant differences between these disjunct populations. We propose a hypothesis of distinct species within the M. vejdovskyi -complex, and critically review all recognized and some unrecognized morphotypes and subspecies. As a result, three new species names are proposed for previously reported populations from Italy and Japan: Maraenobiotus galassiae sp. nov.; M. isidai sp. nov.; and M. pescei sp. nov. Four subspecies of M. vejdovskyi are now elevated to the full specific rank: M. anglicus Gurney, 1932; M. arctica Löffler; M. tenuispina Roy; and M. truncatus Gurney, 1932. This hypothesis remains to be tested using molecular (and other) tools, but can serve as a viable alternative to the concept of polymorphic and widely distributed freshwater harpacticoids.
The number of freshwater species belonging to the genus Parastenocaris reported from ten countries of Southeast Asia is quite limited. Only two species have been reported so far from freshwater ...habitats there, compared to over 290 described species of the family Parastenocarididae worldwide. During the first study of the hyporheic zone of two small rivers in central Vietnam, two new species of the family Parastenocarididae were collected, Parastenocaris sontraensis sp. nov. and Parastencaris vugiaensis sp. nov. Both were collected from the gravel bar along the rivers (Suoi Da and Vu Gia river) using the Karaman–Chappuis method. Both the new species belong to the brevipes group of the genus Parastenocaris Kessler, 1913 sensu Lang (1948), and Reid (1995). Parastenocaris sontraensis sp. nov. is similar to P. hinumaensis Kikuchi, 1970 and Parastenocaris jane Karanovic, 2006 in the brevipes-group. Parastenocaris sontraensis sp. nov. differs from both Parastenocaris species by (i) Exp P3 with three segments in the male, (ii) caudal rami with seven setae, and (iii) caudal rami about 2.4 times as long as wide. Parastencaris vugiaensis sp. nov. can be distinguished from its congeners by the unique combination of the following characters: (i) the elliptical shape of caudal rami, (ii) apical seta (V) with bulbous base, and (iii) anal operculum extends beyond the end of anal somite. Until now, 14 stygobiotic species of Copepoda have been recorded in Vietnam (including two new species in this paper), which is relatively few compared with nearby Thailand with 25 species. Short comments on other stygobiotic Copepoda from Vietnam are added.
Integrity of freshwater surface- and groundwater ecosystems and their ecological and qualitative status greatly depends on ecological processes taking place in streambed sediments overgrown by ...biofilm, in the hyporheic zone (HZ). Little is known about the interactions and effects of multiple stressors on biologically driven processes in the HZ. In this study, machine learning (ML) tools were used to provide evidence-based information on how stressors and ecologically important environmental factors interact and drive ecological processes and microbial biomass. The ML technique of decision trees using the J48 algorithm was applied to build models from a data set of 342 samples collected over three seasons at 24 sites within the catchments of five gravel-bed rivers in north-central Slovenia. Catchment-scale land use data and reach-scale environmental features indicating the HZ morphology and physical and chemical characteristics of water were used as predictive variables, while respiration (R) and microbial respiratory electron transport system activity (ETSA) were used as response variables indicating ecological processes and total protein content (TPC) indicating microbial biomass. Separate models were built for two HZ depths: 5–15 cm and 20–40 cm. The models with R as a response variable have the highest predictive performance (67–89%) showing that R is a good indicator of complex environmental gradients. The ETSA and TPC models were less accurate (42–67%) but still provide valuable ecological information. The best model show that temperature when combined with selected water quality elements is an important predictor of R at depth of 5–15 cm. The ETSA and TPC models show the combined effects of temperature, catchment land use and selected water quality elements on both response variables. Overall, this study provides new knowledge on how ecological processes occurring in the HZ respond to catchment and reach-scale variables, and provides evidence-based information about complex interactions between temperature, catchment land use and water quality. These interactions are highly dependent on the selection of the response variable, i.e., each response variable is influenced by a specific combination of predictive environmental variables.
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•Multiple stressors effects on hyporheic zone were studied using machine learning.•Biological response in hyporheic zone was well predicted by decision tree models.•Models with respiration as response variable had the highest predictive performance.•Temperature, land use and water quality jointly defined hyporheic zone response.•Models provided new knowledge on interactions among stressors.
This bilingual scientific monograph with many illustrations presents the Velika Pasica cave, located on the outskirts of the Gornji Ig village on the Krim massif, around 20 km south of Ljubljana, ...Slovenia. The book presents ecological, taxonomical and biodiversity studies, as well as morphological and historical facts referring to the cave. The cave is small for Slovenian standards, as it is only 105 metres long. On the basis of the specimens collected in the cave, 13 new species from terrestrial and aquatic habitats have been described so far. A considerable number, even on the global scale. The cave was first renowned for the rare cave-dwelling beetles, snails as well as other species. In 2000, a rich community of aquatic animals was discovered, which were not expected to be present there. Since 2006, there have been regular measurements of ecological parameters as well as sampling of fauna from four permanent drips. Fauna was washed-out from a thin layer of dolomite, from which the cave roof consists. The measurements include water and air temperature as well as discharge, measured in one hour intervals. Furthermore, 88 analyses of drip water and an equal number of fauna sampling were conducted. The measurements in the cave were being conducted simultaneously with the measurements of the meteorological parameters on the surface, in the immediate vicinity of the cave entrance.
The time and space dynamics of phytoplankton and its driving factors were studied in Hongfeng Reservoir, southwestern China, from March 2016 to December 2019 to explore the spatiotemporal dynamics ...and driving factors of the phytoplankton community structure. The structural equation model (SEM) was used to analyze the relationship between abundance of phytoplankton and environmental factors in order to determine the main environmental factors that affect changes in phytoplankton. A total of 110 phytoplankton taxa were obtained from six sites. They were members of seven phyla and 68 genera with 12 dominant species or genera. The SEM showed that the main environmental factors that affected the cyanobacteria and diatoms were the temperature (WT), total nitrogen (TN), nitrite nitrogen, nitrate nitrogen, dissolved oxygen, and transparency (SD). Those that affected the Chlorophyta were the pH, TN, ammonia nitrogen (NH
4
+
–N), and orthophosphate phosphorus (PO
4
3−
–P). We concluded that changes in the WT, SD, and the concentration of nutrients significantly affected the abundance of phytoplankton and the dominance of Cyanobacteria and diatoms, whereas these factors had insignificant effects on green algae. The WT, SD, TN and NH
4
+
–N were found to be important environmental factors that affect the structure, growth, and reproduction of the phytoplankton community in Hongfeng Reservoir. This study should provide a scientific reference for the reservoir phytoplankton community ecology and a database on the changes in water quality.
To clarify the indication of plankton fatty acids (FAs) under the influence of the natural environmental factors that affect FA composition and transmission, the Hongfeng Reservoir was investigated ...including plankton community structure and FA composition as well as the physical and chemical indicators of water quality. Thereafter, redundancy analysis (RDA) was performed to analysis the pattern of plankton FA composition during August 2018 to July 2019. The results showed that water quality indicators, including total phosphorus (TP), total nitrogen (TN), chlorophyll
a
(Chl
a
), pH, and DO, exerted significant influence on plankton FA composition. It was also observed that Cyanophyta (
Pseudanabaena limnetica
,
Merismopedia
and
Cylindrospermopsis raciborskii
) and copepod (
Mongolodiaptomus birulai
) constituted the dominant phytoplankton and zooplankton communities, respectively. Further, Saturated fatty acids (SFAs) presented a relatively intuitive indication of the changes in the community structure of Cyanophyta. One of the MUFAs (C16:1) content reflected Bacillariophyta community structure changes. Additionally, there is a good indicational effect between C18:2ω6 and cladocerans, which exhibit a feeding phenomenon toward Cryptophyta. Rotifers obtained C20:2 through Pyrrophyta in order to get polyunsaturated fatty acids (PUFAs). EPA is indication of rotifers. The research results can provide theoretical support for understanding the mechanism of fatty acid transfer among plankton.
Aim
Climatic oscillations altered distributions through migration, extinction, adaptation or speciation. Their joint effect has been rarely studied. Here, we tested how Pleistocene climatic ...oscillations shaped the evolutionary history and distribution of a subterranean amphipod. We tested four predictions for extant populations: (i) populations of good dispersers moving along the ice‐sheet margin should have homogenous genetic structure and broad tolerance to temperatures; (ii) adaptation to local temperatures evolved in poor dispersers with spatially structured populations; (iii) Pleistocene extinctions in the range of historical glaciers should reflect founder effects and high sensitivity to low temperatures; (iv) para‐ or allopatric speciation could unfold through diverse scenarios as a response to local adaptation and constrained dispersal.
Location
North‐Western part of the Balkan Peninsula, Europe.
Taxon
Niphargus stygius, Amphipoda, Crustacea.
Methods
We used time‐calibrated multilocus phylogenies and multilocus delimitations to test independently evolving lineages. For each lineage, separately we assessed historical population dynamics and dispersal potential, modelled climatic niches and mapped them onto palaeoclimatic maps. Additionally, we conducted enzymatic and respiratory tests of thermal tolerance, and reconstructed historical distribution range using phylogeographical diffusion analyses.
Results
We identified four independently evolving tentative species, dated to the Pleistocene, with no evidence of extinction events. Three main lineages are parapatric with few pairwise syntopies and no traces of hybridization. They evolved in allopatry and possibly maintained constant effective population sizes. The lineages are phylogeographically substructured, indicating low recent dispersal. They differ in their climatic niche envelopes and physiological responses to unfavourable temperatures.
Main conclusions
We infer that periodic drops of groundwater in the Pleistocene caused two vicariant events and the onset of two allopatric speciation events, followed by phases of dispersal leading to secondary contact and occasional overlap of ranges. Speciation was seemingly fostered by eco‐physiologically differentiation due to adaptation to local climates.
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