Faunal Zones Research Articles

How morphodynamic gradients shape the distribution of meiofauna and nematodes on sandy beaches of the Amazon region?

The present study analyzed how a small-scale morphodynamic gradient, based on the level of exposure to oceanic waves, shapes the spatial distribution patterns of the local meiofauna, with a special focus on the nematodes, of tropical macrotidal beaches on the Amazon coast (northern Brazil). The study focused on three sandy beaches, first compiling their physical characteristics (waves, currents and morphodynamic state), and then sampling biological and sediment samples at five different levels across the intertidal zone. Meiofauna was composed of 11 different groups, but was dominated by Nematoda. The nematode assemblage had a total of 89 genera, of which Daptonema and Theristus (both from family Xyalidae) were the most abundant on all studied beaches, at most intertidal levels. The diversity of nematode genera increased toward the low tide mark, while nematode density peaked in either the upper (on the protected and tide-dominated beaches) or intermediate levels (on the exposed, tide-modified beach). Distinct faunal zonation patterns were identified on the three beaches, which were influenced by their level of exposure to oceanic conditions, their granulometry, and the moisture of the sediment. While the variation in the characteristics of the meiofauna can be attributed to the level of exposure of beaches, horizontal distribution patterns were also closely related to habitat heterogeneity, including morphological features and freshwater inputs.

Seasonal dynamics of freshwater gastropods in central zone of Kashmir Valley, India

The present study was carried out to study the prevalence and seasonal distribution of snail fauna in central zone of Kashmir valley. A total of 12,103 snails were collected during September 2017 to August 2018 and 10 snail species under 5 genera recorded were Physa acuta, Lymnaea lagotis f. costulata, L. stagnalis, L. brevicauda, auricularia var obliquata, L. luteola f. typica, Gyraulus ladacensis, G. pankogensis, Bithynia troscheli and Indoplanorbis exustus. Besides this, one unidentified snail was also reported. Species-wise overall prevalence was observed highest for P. acuta (18.65%), followed by L. lagotis (15.54%), L. stagnalis (13.31%), G. ladacensis (11.49%), L. brevicauda (10.19%), B. troscheli (8.00%), L. auricularia (6.94%), I. exustus (5.32%), L. luteola (5.15%), G. pankogensis (3.42%) and lowest for unidentified snail (1.94%). Prevalence of snails was found to be highest in summer (53.81%) followed by spring (29.76%), autumn (15.66%) and lowest in winter season (0.75%), the difference being statistically significant between seasons. Overall F% and RF% of snails was observed to be highest for P. acuta followed by Lymnaea spp. other than L. stagnalis, Gyraulus spp., B. troscheli, I. exustus and lowest for unidentified snail. Overall F% and RF% of snails was also observed highest in summer followed by spring, autumn and lowest in winter season. Based on RF%, all snails were found highly distributed, except for unidentified snail, which was found to be lightly distributed. The study concluded that Physa snails were found highly prevalent. Knowledge of the particular snail and cercariae released by them could be used to formulate control strategy to reduce the burden of trematode parasites in animals. Unidentified snail recorded in this study appears to be new species, which needs further detailed investigation.

Do recreational activities affect macrofauna distribution pattern in Amazonian macrotidal sandy beaches?

Recreational activities are important source of disturbance on sandy beaches and have a negative effect on benthic communities as they alter species abundance, diversity, and/or distribution. Here, we report for the first time the effects of the recreational activities on the distribution pattern of macrobenthic communities of Amazonian sandy beaches. Sampling was performed during three consecutive months with different beach use intensity in 2017 (before, during vacation, and one month after the vacation period) on two contrasting beaches regarding disturbance (Urban: Atalaia; and Protected: Corvinas) in the intertidal zone along two equidistant transects at seven equidistant sampling stations: from the high-tide water mark to the swash zone. At each sampling station, four biological and sediment samples were randomly collected. Also, in each station, the sediment compaction was determined using a manual penetrometer. Physical sediment variables remained constant over time in both beaches, whereas differences were found in sediment compaction over the periods. Sediment compaction was considered the most important factor for the differences observed in macrobenthic community structure in the study beaches, and it was related to intensity of recreational activities. Variations in density and changes in richness between periods and sampling stations were observed in Atalaia beach. On the other hand, Corvinas beach remained the same throughout the study. Overall, three faunal zones were distinguished: upper intertidal, intermediate intertidal, and low-intertidal, whereas in the vacation period, only two faunal zones were distinguished: upper-intertidal and intermediate-low intertidal.

Two new species of ektopodontid marsupial from the lower deposits of the Etadunna Formation (latest Oligocene), South Australia and a phylogenetic hypothesis for the Ektopodontidae

Molar morphologies of the latest Oligocene genera, Chunia and Ektopodon, are easy to distinguish, but species determinations are more difficult. As more specimens have been collected, more maxillary fragments with molars and/or alveoli and a portion of the rostrum preserved are available. With a suite of maxillae now known, new ektopodontid features have revealed themselves, including the shortening of the rostrum compared to other families of contemporary possums. The facial angulation represented by the flexure of the rostrum at the boundary between P3 and the molar row results in the rostrum being angled differently than the molar row. Ektopodontids have a significantly greater angulation and thus shorter faces, compared to that seen in contemporary phalangeriform possums. Two new species of the genus Chunia, from the lower Etadunna Formation, South Australia, can be distinguished from the type species, Chunia illuminata, of the Ditjimanka Local Fauna. Differences in molar morphologies and the degree of facial angulation distinguish a new species of Chunia from the lowest faunal zone and the Minkina Local Fauna (facial angulation of 52°) from C. illuminata from the next higher faunal zone (Ditjimanka Local Fauna), which has a greater facial angulation of 63°, while a second new species of Chunia, also from the Dijimanka Local Fauna, has a facial angulation of 58° and intermediate molar traits. The degree of facial shortening is a valid discriminator between species of ektopodontid marsupials as it coincides with the species level differences in dental morphology. Additionally, C. omega from the Tarkarooloo Local Fauna is placed in new genus, Ngathachunia, as it is outside of the hypodigms for both of the previously described genera, Chunia and Ektopodon. A well-supported phylogenetic hypothesis for the family indicates the species of Ektopodon form a monophyletic clade, while the species of Chunia are paraphyletic.Judd A. Case [jcase@ewu.edu], Department of Biology, Eastern Washington University, Cheney, WA 99004, USA. Case, J.A., Month, 202X. Two new species of ektopodontid marsupial from the lower deposits of the Etadunna Formation (latest Oligocene), South Australia and a phylogenetic hypothesis for the Ektopodontidae. Alcheringa XXX, X–X. ISSN 0311-5518.

Can tidal events shape the taxonomic breadth of periphytic protozoa in intertidal zone ecosystems?

To evaluate the influence of tidal events (tidal disruption) on the taxonomic breadth of periphytons in intertidal zone ecosystems, a 1-month baseline survey on protozoan periphyton fauna was studied at five sampling sites from the highest tideline to the lowest (sites A–E) in an intertidal zone of the Yellow Sea, northern China. Samples were collected using an artificial substratum (glass slides) in the sea water with the sediment taken at each sampling site after a 14-day exposure period. The protozoan fauna showed a significant variation in both taxonomic composition and taxonomic distinctness measures along five tidelines. Based on the pair-wised taxonomic distinctness measures (Δ+ and Λ+), the expectation test revealed an increasing departure of the periphyton samples from an expected taxonomic breadth from the highest to the lowest tideline. Therefore, it suggests that tidal events (tidal disruption) may significantly shape the taxonomic breadth of protozoan periphyton fauna in intertidal zones of marine ecosystems.

Biotopes of the intertidal zone in Clarence Island (south of the Strait of Magellan).

The characteristics of the Strait of Magellan promote the formation of unique environments, with diverse habitats and marine organisms. This fragmentation of the landscape generates diverse little-explored ecological associations, especially in the zone of sub-Antarctic islands of the Tierra del Fuego archipelago. One way to address this lack of knowledge is through the biotope characterization methodology, with ecological units composed of the habitat and the communities associated with these environments, obtaining data and information on the dominant and incidental taxonomic groups. This is a good research model to conduct baseline studies in coastal benthic marine environments. A data set in Darwin Core standard is presented of the species that make up the intertidal biotopes of Clarence Island (Tierra del Fuego Archipelago, south of the Strait of Magellan). This includes 50 identified species and the specific coordinates for each sampled location, with a total of 1400 georeferenced records. Mollusks were the most diverse taxon with 21 species, followed by algae (14 species). Sessile organisms such as the barnacles Elminiuskingii and Austromegabalanuspsittacus predominate in these ecosystems, followed by bivalve mollusks such as Choromytiluschorus and Mytiluschilensis, which together with Nacellamagellanica and the alga Hildenbrandia sp. make up more than 50% of the total records. The inclusion of biotope patterns in this study complements the information on benthic marine flora and fauna in the intertidal zone, including new records for the coast in the Clarence Island area, which is within the boundary of the Kawésqar National Park.

Undergraduate Internship on Yamuna River Exploration: Raising Awareness about SDG6

A semester-long internship was designed for undergraduate students at the University of Delhi, India. Teams comprising 30 students from all over the University were trained to carry out field exploration activities on the Yamuna River flowing in Delhi. The students were provided with portable kits to measure the physicochemical parameters at a selected bank of the Yamuna River. Students documented the invertebrate fauna in the riparian zone of the banks. At the same time, they noted the anthropogenic polluting activities on the bank of the Yamuna River. This internship educated students about the UN’s Sustainable Development Goals (SDGs). They all studied Ecology and Environmental Science in their undergraduate curriculum, but they all confessed that they were unaware of the 17 SDGs and the deteriorating health of the Yamuna River in the city. We educated students about the freshwater emergency recovery plan and the International Union for Conservation of Nature (IUCN) red list of ecosystems. This internship is a great example of an undergraduate-directed study or research experience that supported student constructivism and inquiry-based learning, and this research article elaborates on student reports and situational interest in freshwater biology to achieve SDG6.

Astrochronology and sedimentary noise modeling of Pliensbachian (Early Jurassic) sea-level changes, Paris Basin, France

A high-precision global time scale for the Early Jurassic is important for understanding the relationship between biotic, climatic and sea-level changes that occurred during this time interval. In this study, we present a cyclostratigraphic analysis of iron (Fe) and titanium (Ti) elemental data from the Pliensbachian marine mudstone succession of the Sancerre-Couy drill core (Paris Basin, France). Time-series analysis of the data, coupled with existing broad chronological constraints, reveals 405 kyr long-eccentricity, 133–100 kyr short-eccentricity, and 34 kyr obliquity cycles in Ti and Fe abundance. Based on astronomical tuning of the 405 kyr long eccentricity cycles, we construct an astrochronology for the Pliensbachian Stage in the Sancerre-Couy record spanning ∼7.9 Myr. Anchored in numerical time, our new Pliensbachian timescale can be correlated with the thicker, likely more complete, astronomically calibrated Pliensbachian record in the Mochras Farm (Llanbedr) borehole. This exercise suggests the presence of significant hiatuses near the base and top of the Sancerre-Couy record. The recently developed sedimentary noise model for inferring sea-level change has also been applied and compared to previous estimates of Pliensbachian sea-level change derived from the Sancerre-Couy record and elsewhere. Analysis of the sedimentary noise modeling results, previously published nannofossil abundance data and our elemental data suggests the presence of million-year scale cycles linked to long-period astronomical forcing. This work provides new constraints on the chronology of the Pliensbachian and its constituent faunal zones, and the role of long-period astronomical forcing in mediating Early Jurassic paleoclimate and sea-level.

New trilobite assemblage from the lower Cambrian (upper Stage 4) of the Lake Zone, western Mongolia

AbstractThe western Mongolian Lake Zone was a Neoproterozoic to early Paleozoic volcanic arc where tuffs, lavas, fossiliferous siliciclastics, and carbonates accumulated during the early Cambrian. An uppermost Cambrian Series 2 (upper Stage 4) trilobite assemblage is described here from the Burgasutay Formation representing a continuous lower Cambrian succession at the Seer Ridge of the Great Lake Depression. The new assemblage is dominated by dorypygids and consists of 13 trilobite genera belonging to nine families includingCatinouyia heyunensisnew species. These fossils comprise the youngest and richest lower Cambrian trilobite assemblage in Mongolia. The composition of the Lake Zone fauna suggests its biogeographic affinity with the Siberian Platform and Altay-Sayan Foldbelt, but the presence of inouyiids also implies a connection of this region with East Gondwana.UUID:http://zoobank.org/fb0ebe23-144f-46ed-9543-7df9eea85fbc

A revision of the Palaearctic species of the ant genus Cardiocondyla Emery 1869 (Hymenoptera: Formicidae).

A synopsis of the Palaearctic species of the ant genus Cardiocondyla Emery 1869 is provided. The four species groups which are of Palaearctic origin or which are restricted in their distribution to this faunal zone, the C. elegans, C. ulianini, C. batesii and C. stambuloffii group-consisting of 25 recognized species-are taxonomically revised. Further nine species belonging to species groups of Ethiopic and Oriental origin which may penetrate into and build up true outdoor populations in the southern Palaearctic are only treated in the determination key. The main working rationale of this revision is Numeric Morphology-Based Alpha-Taxonomy (NUMOBAT) with formation of species hypotheses largely based on exploratory data analyses and checking these hypotheses by discriminant analysis. NUMOBAT data of the species considered comprise 727 worker samples with 1555 individuals and 23,300 primary data. Including high-resolution photos of surface microstructures, all species are depicted by z-stack imaging in four standard visual positions. Numeric data on 19 phenotypical characters are presented in comparative tables and supplementary verbal descriptions are given. In contrast to species groups with Ethiopian, Oriental and Australasian origin, no member of the four Palaearctic species groups has developed a tramp species potential to spread globally. Four cryptic species are described as new: Cardiocondyla dalmaticoides n. sp., C. caspiense n. sp., C. verdensis n. sp. and C. rolandi n. sp. Confirmed were the synonymies of Cardiocondyla elegans santschii Forel 1905, C. provincialis Bernard 1956 and Xenometra gallica Bernard 1957 with C. elegans Emery 1869, that of C. elegans eleonorae Forel 1911 with C. bulgarica Forel 1892, that of C. elegans torretassoi Finzi 1936 with C. nigra Forel 1905, and that of C. bogdanovi Ruzsky 1905, C. montandoni Santschi 1912 and C. stambuloffii taurica Karavajev 1927 with C. stambuloffii Forel 1892. Cardiocondyla bicoronata Seifert 2003 was newly synonymized with C. nigra Forel 1905.

Description of the First Species of Polylepion (Teleostei: Labridae) from the Atlantic Ocean with Analysis of Evolutionary Relationships of the New Species

Submersible diving in the 1980/90s in the Bahamas and Cuba and 2013–2018 at Curaçao, Dominica, and Roatan resulted in the collection of a new species of Polylepion, a genus of wrasse previously known only from the Indian and Pacific Oceans. The new species, which inhabits the rariphotic reef-fish faunal zone at depths of 219–457 m, is another example of a deep-reef species belonging to a largely shallow-reef family, in this case the family Labridae. Here, we describe the new species and provide a phylogenetic placement for it by adding new sequence data from 12 genetic markers for the new species and one of its two congeners (P. cruentum from the eastern Pacific Ocean) to a previously published dataset comprising 336 species of wrasses that includes the other congener, P. russelli, from the Indian and West/Central Pacific Oceans. Our results resolve the phylogenetic history of the species of Polylepion and provide the first molecular support for the monophyly of the genus.

“A Delicate Equilibrium of the Most Complex Sort”

This article examines the intertidal ecological research of the commercial lab owner and popular science writer Edward F. Ricketts, best known as the prototype for John Steinbeck’s character “Doc” in the novel Cannery Row (1945). Ricketts’s friendship with Steinbeck and unconventional philosophical style have regrettably overshadowed his scientific work, particularly his novel faunal zonation surveys of the North American Pacific littoral in the 1930s and 1940s. These surveys resulted in a landmark handbook, Between Pacific Tides (1939), designed for novices and specialists alike. Ricketts’s work demonstrates how the place of ecological investigation (Billick and Price)—here Monterey Bay’s pounding surf, storm-tossed debris, eclectic bohemianism, and the collaborative energies at Hopkins Marine Station—“imprinted” West Coast animal ecology. At first, Ricketts adopted the physiological methods and conceptions of ecological holism he had learned at the University of Chicago under mentor Warder C. Allee in the early 1920s. Allee had conducted his investigations of intertidal organisms in the relatively placid bays and estuaries at the Woods Hole research center on Cape Cod, Massachusetts. Allee envisioned animal aggregations as higher-order societies guided by “unconscious cooperation” and evolving toward a climax state. Yet Ricketts found that physiochemical factors, such as temperature and salinity, could not explain the distribution of organisms amid the Pacific’s far more precarious rough-and-tumble surf, nor could they account for fierce competition among organisms. Rejecting Allee’s cooperative metaphors, Ricketts came to see community structure as an unintended result of tidepool invertebrates’ Darwinian struggle to occupy resource niches—a “set of sieves” that transferred nourishment from one part of the aggregation to the next, binding it together in interlocking food webs. Through dialogue with Steinbeck about the implications of modern physics during their Sea of Cortez voyage (1940), Ricketts developed a “unified field hypothesis” to conceptualize the dynamic interwovenness created by transfers of metabolic energy. Yet Steinbeck ultimately held fast to a super-organismic understanding of ecological holism—a hierarchical relationship between constituents and the whole that underlays the novelist’s idea of the human “phalanx” in Grapes of Wrath and other works. The article offers new insights about the ecological origins of Steinbeck and Ricketts’s disputes over “non-teleological” reasoning and the pair’s divergent understandings of nature, society, and progressive politics.

Fertilization alters the abundance but not the diversity of soil fauna: A meta‐analysis

AbstractAimSoil fauna, a functionally important group of soil organisms, are greatly affected by fertilization. However, it is still debated whether and how fertilization affects the soil faunal community. Here, we aimed to synthesize the global patterns of soil fauna communities in response to fertilization in terrestrial ecosystems.LocationGlobal.Time period1997–2021.Major taxa studiedSoil fauna.MethodsWe examined the effects of fertilization on the abundance, number of groups and Shannon diversity of soil fauna by synthesizing 1218 observations based on 39 published studies. We also explored the associations between fertilization‐induced changes in the soil faunal community and changes in soil and microbial properties.ResultsFertilization increased the abundance of soil fauna by 56.3%, without significantly affecting the number of groups and the Shannon index. The type of fertilizer affected the responses of soil faunal abundance, and the effects of fertilizer type were altered by climate zones, ecosystem types and soil depths. Both organic and organic–mineral fertilizer treatments significantly increased the abundance of soil fauna in most climate zones, ecosystem types and soil depths, whereas mineral fertilizer treatment had no such effect. Additionally, we found inconsistent responses of soil fauna to fertilization among different taxonomic groups, not only at the order level but also at the class level, providing evidence for the idiosyncratic nature of the effects of fertilization on soil fauna. Furthermore, our regression analysis showed that changes in food resources, including soil nutrients and microbes, were crucial controls for the response of soil faunal abundance to fertilization.Main conclusionsFertilization generally increased soil faunal abundance at the global scale by affecting food resources, and the effects of fertilization were dependent on the specific soil fauna and type of fertilizer. We suggest the use of organic or organic–mineral fertilizers, rather than mineral fertilizers, to increase the benefits on specific soil fauna.

First Description of Invertebrate Benthic Fauna in the Middle Zone of the Loa River (Chile)

Aquatic insect communities in inland waters of Chile are characterised by the presence of certain species depending on water quality, but there is little information on statistical ecology in the structure of insect communities. The aim of the present study was to apply null models to explain the structure of aquatic insects in the middle zone of the Loa River, in the Atacama Desert (Antofagasta Region, Chile; 23°S). The results of the null models of species co-occurrence showed that species associations are random, while niche sharing showed that species share ecological niches and consequently there is interspecific competition. The reported taxa are similar to communities for other North Patagonian rivers in terms of community structure.

A new ektopodontid possum (Diprotodontia, Ektopodontidae) from the Oligocene of central Australia, and its implications for phalangeroid interrelationships

ABSTRACT The Ektopodontidae are an enigmatic group of phalangeroid marsupials known from the late Oligocene to the Early Pleistocene of Australia. Although represented to date only by isolated teeth and several partial dentaries and maxillae, their highly distinctive dental morphology has allowed three genera and nine species to be distinguished. Here, we describe possibly the geologically oldest ektopodontid, Chunia pledgei sp. nov., from the Oligocene Pwerte Marnte Marnte fossil locality of central Australia. Phylogenetic analyses of Phalangeroidea, using 80 primarily dental characters framed by a molecular scaffold, support placement of the new taxon in the genus Chunia. The analyses failed to recover species of the genus Durudawiri in a monophyletic Miralinidae, indicating that they require systematic review. We also transfer the purported basal phalangerid Eocuscus sarastamppi to Miralinidae (Miralina sarastamppi comb. nov.). Additionally, the M1 specimens used to describe the Early to Middle Miocene miralinid genus Barguru, and three species therein, are re-identified as deciduous third premolars from early macropodoids. These findings imply that the Miralinidae are known only from the late Oligocene, whereas the oldest named phalangerids are from the Early Miocene. From a functional consideration of ektopodontid dental morphology, we infer support for prior suggestions of a granivorous and/or frugivorous diet for them. The relative stage-of-evolution expressed by the new taxon is comparable to those in the lower faunal zones of the Namba and Etadunna formations, which supports a late Oligocene age for the Pwerte Marnte Marnte assemblage.

A novel approach to assessing the impacts of dam construction on hydrologic and ecosystem alterations. Case study: Castril river basin, Spain

The hydrological situation of rivers, the fundamental driving force of river ecosystems, has continued to change due to the impact of human activities on water environments. Intra- and inter-annual variation also causes alterations in morphology, water quality, flora, and fauna in riparian zones. In this study, we present a novel approach to assessing the impacts of dam construction on flow river regimes and associated ecosystems in the Castril River (Spain). We compared the altered flows recorded from 2000 to 2018 with those of the natural regime of the river obtained from a previously calibrated hydrological model after the dam was put into operation in 2000. The Indicators of Hydrologic Alteration in RIverS (IAHRIS) method was used because it considers the inter- and intra-annual variabilities of Mediterranean climates. The results showed that the average differences in annual volumes between the natural and altered regimes were below 10% for normal and wet years but decreased to 20.49% in dry years. Thus, the alteration of usual values remained between excellent and good. In droughts and floods, values were from good to moderate, respectively. The flow rate control reduced flow peaks downstream from the dam, decreasing hydrological connectivity of river-riverine-flood plains. This decrease may reduce the transportation of sediment and organic resources, threatening habitat rejuvenation and floodplain biodiversity. This study provides a valuable tool to monitor the impacts of existing dams’ regulated regimens, allowing decision makers to develop flow management strategies and adaptation measures to meet ecological water requirements.

Gastropod Assemblages Associated with Habitat Heterogeneity and Hydrological Shifts in Two Shallow Waterbodies

We aimed to determine the effects of water level and habitat heterogeneity on gastropod fauna in the littoral zone, and the differentiation of functional feeding guilds (FFG) of gastropods. Two periods were analyzed: 2012 (low water level, LWL) and 2013 (high water level, HWL) in the littoral zone of two shallow waterbodies (Sutla backwater, NW Croatia). Waterbody S1, covered with Ceratophyllum demersum, was sampled in the macrophyte stands, and the littoral benthal area, while waterbody S2, without macrophytes, was sampled only in the littoral benthal area. It was observed discovered that among the macrophyte stands in S1, gastropods were significantly more abundant during LWL. The same trend was observed in the littoral benthal area of S2. In contrast, gastropod abundance was higher in the littoral benthal area of S1 during HWL. Comparing gastropods in the two waterbodies, the abundance in S1 was ten times higher than in S2. The most abundant species was Gyraulus parvus, which accounted for 51–92% of the gastropods observed among the macrophytes of S1 and 86% in the adjacent benthic zone. Among the FFG groups, grazers (particularly those feeding on gymnamoebae and rotifers) had the largest proportion, followed by shredders feeding on small pieces of macrophytes. In our research, we indicate the important role of microhabitat diversity and submerged macrophytes as a rich food source for gastropods and safe shelter from predators.

Earthworms (Oligochaeta, Lumdricidae) in the Komi Republic

The article presents information about 11 species in 8 genera of earthworms (Oligochaeta, Lumbricidae) in the Komi Republic. They belong to three morpho-ecological groups inhabiting different soil horizons (litter, litter/soil, soil). The species distribution maps have been compiled. The density of each species and their habitat affiliations in different flatland subzones and altitudinal zones of the Ural Mountains are shown. The number of species tends to decline in a regular manner from southern taiga to shrub tundra, from the Northern to Polar Urals. Boreal zone soils are inhabited by members of the genera Aporrectodea, Dendrobaena, Bimastos, Eisenia, Eiseniella, Lumbricus, Octolasion. Four species: Aporrectodea caliginosa, A. rosea, Eisenia fetida, and Octolasion lacteum, prefer meadows and farmlands. The species Bimastos rubidus and Eiseniella tetraedra inhabit meadows, willow carrs and forests in southern and middle taiga; they are absent in the extremely northern taiga and forest tundra; their habitats in the tundra zone are hydrogen sulfide springs. Three species (Dendrobaena octaedra, Eisenia nordenskioldi, Lumbricus rubellus) have been found in all natural zones and subzones. They compose the Lumbricidae fauna in the tundra zone. Northern Urals harbored the same earthworm species as the boreal zone. Two more species, Rhiphaeodrilus diplotetrathecus and Eisenia atlavinyteae, are representatives of the montane Urals Lumbricidae complex. Five species: R. diplotetrathecus, D. octaedra, E. nordenskioldi, L. rubellus, and O. lacteum, are known for the Subpolar Urals. The species D. octaedra, E. nordenskioldi, L. rubellus have been detected in the Polar Urals as in the tundra zone. The altitudinal distribution of earthworms in the Urals is characterized by the presence of ‘soil’ species in the montane forest zone and a decline in the species diversity in the subalpine and alpine tundra zones, mostly at the expense of the litter/soil group

Habitat variability and faunal zonation at the Ægir Ridge, a canyon-like structure in the deep Norwegian Sea.

The Ægir Ridge System (ARS) is an ancient extinct spreading axis in the Nordic seas extending from the upper slope east of Iceland (∼550 m depth), as part of its Exclusive Economic Zone (EEZ), to a depth of ∼3,800 m in the Norwegian basin. Geomorphologically a rift valley, the ARS has a canyon-like structure that may promote increased diversity and faunal density. The main objective of this study was to characterize benthic habitats and related macro- and megabenthic communities along the ARS, and the influence of water mass variables and depth on them. During the IceAGE3 expedition (Icelandic marine Animals: Genetics and Ecology) on RV Sonne in June 2020, benthic communities of the ARS were surveyed by means of a remotely-operated vehicle (ROV) and epibenthic sledge (EBS). For this purpose, two working areas were selected, including abyssal stations in the northeast and bathyal stations in the southwest of the ARS. Video and still images of the seabed were usedtoqualitatively describebenthic habitats based on the presence of habitat-forming taxa and the physical environment. Patterns of diversity and community composition of the soft-sediment macrofauna, retrieved from the EBS, were analyzed in a semiquantitative manner. These biological data were complemented by producing high-resolution bathymetric maps using the vessel’s multi-beam echosounder system. As suspected, we were able to identify differences in species composition and number of macro- and megafaunal communities associated with a depth gradient. A biological canyon effect became evident in dense aggregates of megafaunal filter feeders and elevated macrofaunal densities. Analysis of videos and still images from the ROV transects also led to the discovery of a number ofVulnerable Marine Ecosystems (VMEs) dominated by sponges and soft corals characteristic of the Arctic region. Directions for future research encompass a more detailed, quantitative study of the megafauna and more coherent sampling over the entire depth range in order to fully capture the diversity of the habitats and biota of the region. The presence of sensitive biogenic habitats, alongside seemingly high biodiversity and naturalness are supportive of ongoing considerations of designating part of the ARS as an “Ecologically and Biologically Significant Area” (EBSA).

Spatial Distribution of Cyclograpsus cinereus Dana 1851 on the Rocky Shores of Antofagasta (23°27′ S, Chile)

The decapod fauna in the intertidal zone of the rocky shores of Chile is highly diverse, especially along the northern and central mainland coasts, where the influence of the cold Humboldt Current results in high productivity. One of the most abundant species in these ecosystems is the decapod Cyclograpsus cinereus Dana, 1851. The aim of the present study, carried out in the spring and summer seasons between 2018 and 2020, was to determine the spatial distribution patterns of the decapod C. cinereus in different sites along the rocky shores of Antofagasta bay, northern Chile, in order to establish probabilistic models that explain its distribution at each site. Individuals were counted in random quadrants in the intertidal zone. The data thus obtained were processed by application of the variance/mean ratio to determine whether the distribution of individuals was random, aggregated or uniform, associated with Poisson, negative binomial or positive binomial distributions, respectively. The data revealed aggregated (negative binomial) distribution in 15 sampling events, and uniform (positive binomial) distribution in 4 events. The sampling sites were located on rocky shores in four sectors of an urban zone, and two in a protected zone; no significant differences were found between the densities of the sites in the two zones. The results of the interpretative probabilistic models indicated aggregated distribution patterns, agreeing with previously reported interpretative probabilistic models for the distribution of decapods on the rocky shores of central and southern Chile.