Explore the vast range of titles available.

Abstract In spite of the important ecological roles of copepods, their phylogeny and taxonomy remain largely unexplored in China. Here, we investigated the taxonomy and diversity of some Sinocalanus species (Copepoda, Calanoida, Centropagidae) in China. We observed two morphospecies (S. tenellus and S. doerrii) from this genus in 42 of 636 Chinese waterbodies examined. Molecular phylogenies inferred from a mitochondrial (mitochondrial cytochrome c oxidase subunit I; COI) and a nuclear marker (the nuclear 18S ribosomal RNA gene; 18S) verified the identities of these species and allowed us to amend previous misidentifications. Pronounced ecological separation between the two Sinocalanus species detected was found: S. doerrii inhabited freshwaters and was widely distributed across China, whereas S. tenellus was mainly found in brackish estuaries. One clade of S. doerrii had been misidentified (based on molecular data only) as S. tenellus in previous works, with consequent mislabeling of the sequences uploaded to GenBank. Additionally, we detected a new mitochondrial lineage of S. tenellus, most frequently in Jiaozhou Bay, China, whereas its sibling lineage was distributed in estuaries along the coasts of the East China Sea. Our study contributes to understanding the taxonomy and genetic diversity of the genus Sinocalanus in Chinese freshwater and brackish-water ecosystems.

This work aims to analyze the zoogeographic distribution of Calanoida in Kazakhstan. Kazakhstan belongs to the Palaearctic region, and its territory is ascribed to the European–Siberian and Nagorno–Asian biogeographical subregions. The European–Siberian subregion includes the Volga–Ural, Irtysh, and Turkestan–Aral provinces. The Balkhash province belongs to the Nagorno–Asian subregion. Studies of the Calanoida fauna were carried out between 1997 and 2019. For this purpose, 7250 zooplankton samples were taken in 130 different water bodies. Findings of 26 species of Calanoida have been documented. The richest in species composition (20) is the Calanoida fauna of the Irtysh province. Ten Calanoida species have been recorded in the Volga–Ural province, 8 in the Turkestan–Aral province, 7 in the Balkhash province, and 5 in the Ponto–Caspian region. The distribution of the species richness of the order is determined by a complex of climatic factors, including the density of the hydrographic network, a variety of hydrochemical conditions, and accidental acclimatization of species. Far Eastern species (Sinodiaptomus sarsi, Neutrodiaptomus incongruens, Neodiaptomus schmackeri) entered the inland water bodies of Kazakhstan, most likely through the introduction of non-native fish species. The Black Sea species Acartia tonsa and Calanipeda aquaedulcis were introduced into the Caspian Sea with ballast waters. Three autochthonous species (Limnocalanus macrurus, Eurytemora grimmi, Eurytemora minor), formerly inhabiting the Caspian Sea, can now be considered extinct. Acanthodiaptomus denticornis, Arctodiaptomus (R.) salinus, Phyllodiaptomus blanci, and Eudiaptomus graciloides are widespread in the region. Endemic species (Gigantodiaptomus irtyshensis, Arctodiaptomus naurzumensis) and species are new for Kazakhstan (Diaptomus (Chaetodiaptomus) mirus, Eudiaptomus transylvanicus, Arctodiaptomus dentifer, A. (Rh.) ulomskyi were found in small waterbodies; they are known only from single occurrence sites as well as Eurytemora caspica. The last one was described from the northern part of the Caspian Sea, in the coastal zone. Further research into small water bodies that are poorly studied may expand our knowledge of the diversity of Calanoida in Kazakhstan. Calanoida fauna of Kazakhstan was closest to the fauna of countries with a continental climate and most strongly differed from countries with subtropical and Mediterranean types of climates.

Abstract—Limnocalanus macrurus Sars 1863 (Calaniformes, Centropagidae Giesbrecht 1892) is a glacial marine relict species. In the pelagic zone of Lake Onego, one of the European Great Lakes, this copepod is part of the zooplankton dominant complex all year round. Limnocalanus macrurus is a monocyclic species with one generation and winter reproduction. Based on the analysis of long-term data, the main features of the life cycle of the copepod have been studied in Petrozavodsk Bay and in the central part of Lake Onego. Thus, during the growing season the average values of abundance are two times lower in the bay compared to the central part of the lake (2700 vs. 5500 ind./m2, respectively). The same tendency was observed in relation to biomass (0.82 vs. 1.36 g/m2, respectively). A comparison of the average long-term maximal values of abundance and biomass in these parts of the lake also shows that the values of abundance are 1.6 times (5600 vs. 9000 ind./m2), while the biomass values are twotimes lower (1.41 vs. 2.83 g/m2) in Petrozavodsk Bay compared to the central part. A shift in the timing of the spring development of L. macrurus in Petrozavodsk Bay has been found; here the development begins 2–3 decades earlier due to the difference in the thermal regimes of the areas compared. Despite the climatic changes observed in recent decades, no significant changes in the abundance of L. macrurus have been detected in the lake.

Copepods are present in numerous aquatic environments, playing key roles in food webs, and are thought to be useful indicators of environmental change. Boeckella is a calanoid copepod genus distributed mainly in the Southern Hemisphere, with 14 species reported at higher southern latitudes in South America and Antarctica. We present an updated database of these 14 species of Boeckella generated from a combination of three sources: 1) new field sampling data, 2) published records, and 3) Global Biodiversity Information Facility (GBIF), to provide a comprehensive description of the geographic distribution of the genus south of latitude 40°S in southern South America and the three main terrestrial biogeographic regions of Antarctica. The database includes 380 records, 62 from field sampling, 278 from the literature and 40 from GBIF. Southern South America, including the Falkland/Malvinas Islands, had the highest species richness and number of records (14 and 297, respectively), followed by the sub-Antarctic islands (5 and 34), South Orkney Islands (2 and 14), South Shetland Islands (1 and 23), Antarctic Peninsula (1 and 10) and finally continental Antarctica (1 and 2). Boeckellapoppei Mrázek, 1901 is the only representative of the genus, and more widely the only terrestrial/freshwater invertebrate, currently reported from all three main biogeographic regions in Antarctica (sub-Antarctic islands, maritime and continental Antarctic). Future development of molecular systematic studies in this group should contribute to assessing the correspondence between morphological taxonomy and molecular evolutionary radiation.

Abstract Several independent methods: molecular-genetic, biogeographical, and morphological analyses — were applied to explain the origin of the continental calanoid fauna and the distribution of their recent genera. The theory of Continental Drift and the evolution of the Tethys Sea were also used for that purpose. The molecular-genetic-based phylogenetic tree that we constructed, as well as the largest number of genera and species in Diaptomidae, allow us to support the idea that this family of fresh- and brackishwater Copepoda arose earlier than the Temoridae and Centropagidae. The ancestors of the Diaptomidae likely invaded, and were distributed across, the supercontinent Pangaea before its division into two continental plates in the Mesozoic Era, i.e., not later than 180-200 Ma. Therefore, various genera of this family can be found almost everywhere on all continents, except Antarctica. The family Temoridae is known only from Europe, Asia and North America. These three continental plates stayed together long after separation of Pangaea into two parts: Laurasia and Gondwana (until circa 50 Ma). At approximately the same time (50 Ma), the genus Eurytemora should have been created, as its representatives are known from North America and Eurasia. The family Centropagidae seems to have invaded inland waters somewhere between Temoridae and Diaptomidae, as its representatives can be found on all continents except Africa. Also, as a possibly alternative option, this centropagid invasion could have happened independently in the northern and southern Pangaea blocks, by different marine ancestors, at the same time as Temoridae, as is shown herein in the molecular-genetic-based phylogenetic tree. Using the evolution model of the Tethys Sea proved to be very productive for explaining the modern ranges of continental calanoids, both within families and in individual genera, including the genus Eurytemora.

Freshwater calanoid copepods develop abundant populations in lentic water bodies such as lakes, reservoirs and lagoons. In this study, we examined the potential habitat value of edges in lotic systems such as creeks and rivers where waters tend to stagnate, providing lentic-like environments. We examined a total of 353 edge samples collected from 321 sites across the state of New South Wales, Australia, with latitudes in the range 28.3–37.4°S and elevations in the range 2–1834 m above sea level. Of the total samples examined, calanoid copepods were found in 94 samples, with the frequency of occurrences of species decreasing in the order: Boeckella fluvialis Henry, B. triarticulata (Thomson), Gladioferens spinosus Henry, G. pectinatus (Brady), B. major Searle, B. minuta Sars, and Calamoecia lucasi Brady. The probability of occurrence of the calanoid copepods was related negatively to both latitude (as absolute values) and elevation, based on logistic regression models. We conclude that the edges of many lotic systems provide additional habitats for some species of freshwater calanoid copepods, with constraints on their distributions along latitudinal and elevational gradients.

We present new records of Boeckella bergi at several water bodies in Argentina and Brazil. Within these records the northernmost and southernmost limits of occurrence of B. bergi in South America are included. The ample range of distribution is consistent with former studies, but it is more extensive than previously known. Observations on habitat preferences are also made. This species is tolerant to temperate climate conditions in this region of South America, with wide amplitude of temperature between summer and winter seasons, and irregular patterns of precipitation.

Copepods, present in a wide range of water bodies, are an important component of freshwater ecosystems and their biodiversity has been much studied in marine and freshwater ecosystems. However, no previous genetic data are available that allow an assessment of population-genetic diversity and differentiation of the copepod Sinocalanus tenellus from Chinese freshwaters. We analyzed DNA sequences of the mitochondrial cytochrome c oxidase subunit I (COI) gene from eleven S. tenellus populations (individual lakes) from China, ten of which exhibited a high genetic diversity. Low to high population differentiation was detected among the populations. Interestingly, substantial genetic divergence was detected between WLS (Wuliangsu, in Inner Mongolia) and other locations, indicating the presence of two lineages of S. tenellus in East Asia. Moreover, we found that two distinct clades of S. tenellus were separated by the reference “S. sinensis” clade, suggesting they were parts of a complex of cryptic species of S. tenellus. This study will contribute to an understanding of the diversity and biogeography of copepods in freshwater ecosystem in China.

The composition of the zooplankton community in a macrotidal (8 m tidal range), tropical estuarine system (Darwin Harbour, Australia; 12°28' S, 130°50' E) was studied over a 2 year period with the goal of describing biodiversity and determining the environmental factors that have the greatest impact on community structure. Most (82-84%) of the >73 μm plankton was composed of copepod nauplii and copepodites, and plankton samples taken with larger, coarser meshed (150 and 350 ìçé) nets did not contain significant numbers of larger (non-copepod) organisms. In all, 32 copepod species were recorded, with small euryhaline marine copepod species such as Parvocalanus crassirostris, Bestiolina similis and Oithona aruensis dominating the zooplankton. Plankton abundances ranged between 30,000 and 110,000 m⁻⁳, and there were significant year (2003 > 2004), season (wet > dry) and site differences (inner harbour sites > outer harbour sites), but negligible diurnal differences. Multivariate analyses identified three sample groups: (1) middle and outer harbour sites, (2) inner harbour and river sites and (3) the river site during the wet seasons. Middle and outer harbour stations were characterised by a diverse mixture of coastal copepods, whereas inner harbour and river sites were dominated by P. crassirostris and O. aruensis. During the wet season, there was a distinct copepod community within the Blackmore River, dominated by Acartia sinjiensis, Oithona nishidai and Pseudodiaptomus spp. Environmental variables (nutrients and chlorophyll a) were correlated with salinity, which had the strongest influence on community structure. There was a significant drop in species richness from harbour to river sites. Small copepods of the families Paracalanidae and Oithonidae dominate tide-dominated Australian tropical estuaries, whereas copepods belonging to the family Centropagidae (such as Gladioferens spp.) appear to be characteristic of wave-dominated estuaries in southern Australia.

Although it is commonly acknowledged that calanoid copepods inhabiting fresh water evolved from marine ancestors via the brackish water of estuaries, it is less well appreciated that a restricted number of species with freshwater affinities have conquered athalassic saline waters. The global importance of the latter habitat has been under-estimated and, with climate change and human population growth, it is expanding at the expense of fresh waters. Considering Australia, South America and the Holarctic, at least seven halobiontic calanoid species occur in athalassic saline waters (the situation in Africa is not visited). In Australian inland-water Centropagidae, there is a high degree of congruence between the ecological trend in habitat occupancy (marine through brackish and fresh to athalassic saline waters) and the assumed evolutionary trend towards reduction in the setation and segmentation of swimming legs. The validity of the inference by Adamowicz et al. (Biological Journal of the Linnean Society of London 90: 279-292, 2007a) that a hypothesis of oligomerization was not supported as the mode of evolution of South American non-marine Centropagidae is criticized for reasons of inadequate character sampling. The phylogeny, biogeography and osmo-regulatory physiology of Southern Hemisphere inland-water centropagids are reviewed in some detail. Calanoids have mastered a significant portion of the total salinity range for athalassic saline waters (3 to 300+ g l⁻¹) but, unlike brine shrimps, they have not evolved a mechanism for hypo-osmotic regulation and do not tolerate saturated or near-saturated brines.