Hermit Crab Research Articles

PAGURIZED GASTROPOD SHELLS IN A NORTHEAST BRAZILIAN COASTAL LAGOON AT THE SEA-ESTUARY INTERFACE

Gastropods are known for the presence of calcareous shells, even after their death. The diversity of this resource can be reflected in the local diversity of living gastropods. These shells are used by hermit crabs as protection and against desiccation. Coastal lagoons are biodiversity hotspots and the site of recruitment of continent-sea connectivity, and their diversity is sometimes altered by connectivity events with adjacent areas. Therefore, we sought to make a list that evaluates the seasonal variation of diversity and demonstrates the pattern of shell use by hermit crab species. The samplings were standardized in six monthly repeated transects from February 2013 to January 2014, using a fishing net trawl. The shells were identified to species level and quantified. Diversity indexes were calculated, seasonally, for the assemblage of used shells. Hermit crabs used 14 species of gastropod shells, of which Vitta virginea and Phrontis vibex were the most abundant and frequent. The diversity indexes indicated a temporal variation of the shells, with April the month showing the highest difference in diversity. A reflection of the change in surface geomorphology, caused by the King Tide, it’s discharge and carrying of empty gastropod shells to the open sea. The usage patterns of these biogenic remains can reveal strategies of decreased intra/interspecific competition. Furthermore, we described the first record in the Brazilian Northeast of the hermit crab C. symmetricus, after its taxonomic resurgence.

Does microplastic exposure and sex influence shell selection and motivation in the common European hermit crab, Pagurus bernhardus?

Microplastics (<5 mm) are a threat to marine biodiversity however their effects on animal cognition and behaviour are unclear. We investigated whether microplastic exposure affects shell selection behaviour and motivation in the common European hermit crab, Pagurus bernhardus. Subjects were maintained for 5 days in tanks containing either: polyethylene microplastic spheres (n = 40), or no plastic (n = 40). They were then placed in low-quality shells and presented with an alternative high-quality shell. When they first touched the high-quality shell, the hermit crabs were startled using visual and aural stimuli. We recorded the post-startle latency to re-contact the high-quality shell, quantifying motivation to explore and acquire a better shell. Plastic-exposed females were more likely to select the high-quality shell than control females. As hypothesised, female hermit crabs had longer initial contact latencies, startle durations, and shell entry latencies than males. We also found an interaction effect on shell investigation duration: females from the control treatment spent longer investigating the high-quality shell compared to males. This was absent in the microplastic treatment with females behaving similar to males. This controlled study serves as a starting point to investigate the effects of microplastics and sex differences on behaviour when under predatory threat, and demonstrated sex dependent sensitivity to an environmental pollutant of global concern.

Profiling abundance, size, and shell utilization patterns ofCoenobita clypeatus(Fabricius, 1787) (Decapoda: Anomura: Coenobitidae) in protected and highly frequented beaches in Puerto Rico

AbstractThe coastal Caribbean is a well-known harbor for biodiversity, yet it is mainly valued for its ample resources and services. Economic interests typically supersede conservation efforts, introducing anthropogenic-related factors such as noise, chemical pollution, and geographical disturbances into the littoral zone, where ecological diversity is abundant. Although human activity is known to be detrimental to biodiversity across habitats, the effect of conservation measures that limit anthropogenic activity on coastal populations remains understudied. To measure the benefit of conservation in the littoral environment, we sampled populations of the hermit crab Coenobita clypeatus (Fabricius, 1787) of highly frequented (non-protected) and protected beaches in northern Puerto Rico. We profiled 1,119 individuals by using transects, describing their size and shell utilization patterns during winter and summer. The C. clypeatus population was larger (P &amp;lt; 0.0001 during both seasons) and more abundant (P = 0.0006 during winter, P &amp;lt; 0.0038 during summer) in the protected beach than in the non-protected beach, with no effect of season. Shell utilization patterns were more consistent in the protected beach, likely due to the greater availability of gastropod shells. These results suggest that the conservation measures implemented in the protected beach promote the survival, reproduction, and growth of hermit crabs in the location. Expansion of protected habitats through governmental and civilian efforts should enhance the conservation of the biodiversity of protected areas.

A new species of the diogenid hermit crab genus Pseudopaguristes McLaughlin, 2002 from the Northern Mariana Islands, Micronesia.

The diogenid hermit crab genus Pseudopaguristes McLaughlin, 2002 is currently represented by 15 species worldwide. In this study, we describe a new species of the genus, P. flavioculus, based on a unique male holotype from off Sarigan, Northern Mariana Islands, Micronesia, at depth of 131133 m. The new species appears similar to the type species of the genus, P. janetkae McLaughlin, 2002, but the lack of conspicuous spines on the dorsal face of the right cheliped carpus, the possession of a median row of tiny spines on the dorsal face of the left cheliped carpus, and different colour pattern of the cephalic appendages and the ambulatory legs distinguish P. flavioculus n. sp. from P. janetkae. Pseudopaguristes has been differentiated from the two allied genera, Paguristes Dana, 1851 and Areopaguristes Rahayu, 2012, by the possession of eight functional pairs of gills (versus 13 pairs in Paguristes and 12 pairs in Areopaguristes), but our examination of the new species and three other congeneric species available for study clarifies that the development of arthrobranchs on the maxillipeds 3 and chelipeds is rather variable in species currently assigned to Pseudopaguristes. Careful observation of the anterior arthrobranchs is recommended to avoid misinterpretation in the counts of gill numbers.

Distribution of Decapods in the Selected Mangrove Sites in Sta. Maria, Davao Occidental, Philippines

Aims: To identify the species of decapods and their edibility, determine the population density, abundance, dominance, and diversity indices of decapods found in the selected mangrove sites, and measure the physicochemical parameters of the area.&#x0D; Place and Duration of Study: Barangay Tanglad, Mamacao, and Basiawan of the Municipality of Sta. Maria, Davao Occidental. April 25-29, 2022.&#x0D; Methodology: A transect-plot method was used in sampling and the samples were handpicked or captured using tongs, scooped using the locally used net, dug from their burrows, and collected from wooden hides. The samples were put in a container with seawater and ice, then cleaned, photographed, and identified. The samples were presented to the fisherfolks and locals to identify local names and their edibility. The pH, temperature, and salinity of the seawater were recorded on site. The decapods’ taxonomic classification was identified. The population density, abundance, dominance, and diversity indices were computed.&#x0D; Results: There were 13 species of decapods found in the three sampling sites, namely: Triangular fiddler crab (A. triangularis), Nymph snapping shrimp (A. euphrosyne), Mud crab (B. vinosus), Forceps crab (E. dentatus), Brown land crab (C. carnifex), Hermit crab (C. rugosus), Indian prawn (F. indicus), Giant freshwater prawn (M. rosenbergii), Alamihi crab (M. thukuhar), Mudflat crab (P. pictum), Flat porcelain crab (P. cinctipes), Mangrove swimming crab (T. crenata), and Compressed fiddler crab (T. coarctata). A total of 633 individuals were gathered from the three sampling sites. 279 individuals were collected in Barangay Tanglad, 189 individuals in Barangay Mamacao, and 165 individuals in Barangay Basiawan. Triangular fiddler crab (A. triangularis), Hermit crab (C. rugosus), Indian prawn (F. indicus), Alamihi crab (M. thukuhar), Mudflat Crab (P. pictum), and Compressed fiddler crab (T. coarctata) were observed to be present among the three sites. In the three sampling sites, Mudflat crab (P. pictum) showed to have the highest population density of 199 ind./2,700 m2, highest index of the dominance of 0.291, and a relative abundance of 31.44%. Mudflat crab (P. pictum), Triangular fiddler crab (A. triangularis), and Compressed fiddler crab (T. coarctata) were the most dominant species in the area.&#x0D; Conclusion: Barangay Tanglad was found to be the most diverse site, it also had the highest index of evenness. Barangay Mamacao and Basiawan had the highest similarity index. There was no significant difference in the number of decapod species between the sampling sites. The physicochemical parameters are within the optimum level which could be a favorable condition for the abundance of the decapods.

Filling the early Eocene gap of paguroids (Decapoda, Anomura): a new highly diversified fauna from the Spanish Pyrenees (Serraduy Formation, Graus-Tremp Basin)

AbstractA highly diversified fauna of hermit crabs associated with reef environments from the Serraduy Formation (lower Eocene) in the southern Pyrenees (Huesca, Spain) is described. Other European Eocene outcrops have yielded paguroids associated with a single environment; however, the studied association represents one of the highest paguroid diversities in a single Eocene outcrop worldwide. The new material increases the diversity of known fossil paguroids, including eight species from which six are new: Clibanarius isabenaensis n. sp., Parapetrochirus serratus n. sp., Dardanus balaitus n. sp., ?Petrochirus sp., Eocalcinus veteris n. sp., ?Pagurus sp., Paguristes perlatus n. sp., and Anisopagurus primigenius n. sp. We erected a new combination for Paguristes sossanensis De Angeli and Caporiondo, 2009 and Paguristes cecconi De Angeli and Caporiondo, 2017 and transfer them to the genus Clibanarius. This association contains the oldest record of the genera Eocalcinus and Anisopagurus. Our data demonstrate that paguroids were diverse by the early Eocene in coral-reef environments and fill an important gap between the poorly known Paleocene assemblages and the more diverse mid- to late Eocene ones.UUID:http://zoobank.org/091f7a79-946c-4cd9-bdad-f727695e8503

A Laboratory Study of the Effect of Temperature on the Embryonic Diapause of the Hermit Crab Pagurus proximus Komai, 2000 (Decapoda: Paguridae) from Peter the Great Bay, Sea of Japan

A Laboratory Study of the Effect of Temperature on the Embryonic Diapause of the Hermit Crab Pagurus proximus Komai, 2000 (Decapoda: Paguridae) from Peter the Great Bay, Sea of Japan

Caution is required when considering sentience in animals: a response to the commentary by Briffa (2022) on "Hermit crabs, shells, and sentience" (Elwood 2022).

My recent review examined the complex and intimate relationship between hermit crabs and the empty gastropod shells upon which they depend for survival. Because shells come with costs as well as benefits, the crabs are highly selective about which ones they prefer to occupy. Thus, a new shell is investigated and the information that is gathered appears to be compared with their existing shell before a decision is made. This is often prolonged and complex. Crabs also fight for shells and again the information that is gathered and used to inform fight decisions is complex. In my review, I consider these and other situations with reference to the possibility of sentience (including awareness). The excellent commentary from Mark Briffa expands on aspects of sentience and invokes the use of Lloyd Morgan's Canon to avoid suggesting complex abilities when simpler explanations would suffice. I agree with this approach. However, I also suggest that when simpler explanations appear not to explain the data, then it is reasonable to consider if more complex mental abilities might be used. I also like Briffa's suggestion that the use of an apparently higher mental faculty might result in a mechanism that is simpler than a large number of apparently simple decisions used to make complex decisions.

The insecure skin‐ego: Conspiracy theories as a source of containment in a pandemic

AbstractIn analyzing the psychological reactions to the recent COVID‐19 pandemic, we have tried to show that the existing societal protective skin that gives unity to people by creating a secure containment was too thin and fragile to cope with an annihilation situation such as the pandemic. This healthy and protective societal skin acts continuously as a maternal environment, providing physical and mental security. As a modest contribution, we provide psychoanalytic, social, cultural, and political analyses of the conspiracy theories and infodemics in the mid‐COVID‐19 era. We extend Anzieu's theory of skin‐ego from a maternal‐centered conceptualization to one based on a wider range of caregivers, including politicians, health care professionals, scientists, and researchers—who act as the suppliers of containment. During the pandemic, the common protective skin showed initial flexibility as it tried to regenerate a secure common skin with the help of the health care system and other state organizations responsible for managing the COVID‐19 pandemic. However, the common protective skin is under continuous attack by various politicians around the world, like the hyper‐masculine figure of Donald Trump who attacked this common skin, increasing the insecurity and helplessness of people. Like hermit crabs, thin‐skinned people with insecure skin‐egos sought refuge inside the shell of Trump's safer and thicker skin. A shell of conspiracy theories and infodemics provided by crustacean Trump functioned as a thick, protective skin. To illustrate our ideas, we present events and reactions from the pandemic and also cite two illustrative examples—the story of Noah's Ark and the children's classic, The Three Little Pigs.

Metabarcoding of zooplankton confirms southwards dispersal of decapod crustacean species in the western Indian Ocean

Metabarcoding to determine marine zooplankton species composition is a fast-developing method, yet to be fully standardised. DNA barcode reference libraries that link species to barcode sequences remain incomplete, taxonomically imprecise, and biased towards well-studied regions. We used metabarcoding to determine the decapod crustacean species present in the marine zooplankton off eastern South Africa, a region for which reference libraries are comparatively poor. Zooplankton communities were sampled with tow nets at stations on the shelf (20- and 50-m isobaths) and at the shelf edge (100- and 200-m isobaths), and the samples were processed using high-throughput sequencing technology. The cytochrome c oxidase subunit I (COI) gene region was used for taxonomic assignment of amplicon sequence variants to species level at 95% and 99% similarity to barcode records. Detected species were cross-referenced against occurrence records from the region. Eighty- one decapod species were detected at 95% sequence similarity, but this declined to 60 species at the stricter 99% threshold. False-positive identifications were reduced by 60%. True crabs (Brachyura) were proportionally over-represented; the ratios of prawns (Dendrobranchiata), lobsters (Achelata) and burrowing shrimp (Axiidea) were consistent with occurrence records; and true shrimps (Caridea) and hermit crabs (Anomura) were under-represented. Metabarcoding identified 19 tropical western Indian Ocean (WIO) species in the samples from eastern Africa, confirming a southwards dispersal of drifting phases through the Mozambique Channel. Congruence of WIO species with the Agulhas Bioregion (shelf-edge detections) and Delagoa Biozone (shallow detections) was consistent with the dispersal of tropical species in warmer water masses. Metabarcoding of marine zooplankton communities to obtain species-level information advances high-resolution ecological research in pelagic ecosystems.

Morphology and their abundance of marine hermit crabs In Zee-Phyu-Thaung coastal areas, Mon state, Myanmar

The morphological characters of marine hermit crabs from mangrove forests and rocky and sandy shores around Zee-phyu-thaung and its adjacent coastal areas were conducted from September to November 2018. Consequently, a total of 5 species in 2 genera and 1 family were identified with their distinguished characters including Clibanarius infraspinatus (Hilgendorf, 1869), Clibanarius padavensis De Man, 1888, Clibanarius merguiensis de Man, 1888, Diogenes edwardsii (De Haan, 1849) and Diogenes alias McLaughlin & Holthuis, 2001. Among them, C. padavensis (Bosc, 1802) and D. alias McLaughlin & Holthuis, 2001 were first records for Myanmar’s hermit crabs. Moreover, C. padavensis and D. edwardsii was the most abundance species in Zee-phyu-thaung.

Size specific boldness associated with differences in resource requirements and habitat use: a cross-sectional study in hermit crabs.

Animal personality is often studied within compressed periods of observation that represent narrow windows in comparison to animal lifespans. Although much is known about the relations between repeatable personality traits and cross-situational behavioral plasticity, less is known about how such traits might differ across age classes or life history transitions. We conducted a cross-sectional study of startle response duration in 3 size classes of Pagurus bernhardus, the common European hermit crab. We defined size classes using transitions in the preferred species of gastropod shells that accompany growth, and this change in preference is in turn associated with a transition from intertidal to subtidal habitats. Compared with small- and medium-sized intertidal individuals the larger subtidal hermit crabs behaved cautiously by showing startle responses of greater duration following disturbance. Startle responses were also repeatable within all 3 size classes, confirming the presence of animal personality in intertidal hermit crabs and demonstrating that this pattern is retained within the largest size classes, which have undergone the transition from intertidal to subtidal habitat. Interestingly, there was a trend for the pattern of repeatable startle response durations to increase with size class, with the highest value for repeatability and the greatest range of startle response durations being present within the large subtidal population. The greater range of startle responses indicates that the longer startle response durations in some larger individuals are more likely due to developmental changes with age and habitat use than reflecting selection against the boldest individuals during earlier stages of life.

Movement pattern and population structure of Clibanarius antillensis Stimpson, 1859 in south Brazil

AbstractHermit crabs have soft abdomens and therefore must use empty gastropod shells as protection. Shell choices do not occur at random, and the animals often occupy shells with the best fit among the available ones. To live in intertidal and sublittoral zones, regions subjected to daily variations in abiotic factors, hermit crabs present a locomotory circadian rhythm. Clibanarius antillensis has been the object of several studies in Brazil's south-east, so this study was aimed at describing its population in the south of Brazil and its movement activity under laboratory conditions during night-time and daytime, while using two different shells. The animals were sampled from the Sepultura and Lagoinha beaches, in the state of Santa Catarina through free diving. Sex ratio was skewed for males, with ovigerous females present during the whole year but with a spring peak. Males were more abundant than females, ovigerous females and intersex individuals, being predominant in all size-classes analysed. The hermit crabs occupied mainly two gastropod shells: Cerithium atratum and Agathistoma viridulum, and ovigerous females used only the first. Clibanarius antillensis showed nocturnal activity and the animals using C. atratum shells were more active than those using A. viridulum. Cerithium atratum shells are lighter and less bulky than A. viridulum, implying that there might be a tradeoff in which the hermit crabs use lighter shells, that provide less protection in order to expend less energy and be more active.

The differences in the trophic structure of semi‐enclosed and open coastal communities under the influence of an alien top predator (red king crab in the Barents Sea)

AbstractThe impact of the introduced red king crab (RKC), Paralithodes camtschaticus, in the Barents Sea was mostly studied through its direct predation on native species. This study uses stable isotope analysis of carbon and nitrogen to characterize major trophic groups (including grazing sea urchins) and specifically looks at RKC's trophic position and niche partitioning with the native hermit and spider crab species. To achieve this, we sampled organisms from the food web of a small fjord‐like Zelenaya Inlet on the Murmansk coast in the southwestern Barents Sea and the open sea coast, just outside the inlet for comparison. There, macrophyte‐derived carbon is the major source of organic matter along with the phytoplankton. In general, the fucoid source of primary production was more prominent within the inlet food web compared to the nearby open coastal zone. Isotopic trophic niches calculated using SIBER analysis showed partition between the native hermit and spider crabs suggesting, some degree of trophic segregation between coevolved species. RKCs are clustered together in the center of native decapod species' niches. There were some distinct differences between the feeding habits of RKCs within the inlet and the open sea coastal waters. The subadult RKCs that are present in the inlet throughout the year have a narrower (in the area and specifically in δ15N dimension) niche than the adults from the open sea. The latter have a wider variety of food items due to their migration and may prey on food items from different trophic levels. Sea urchins are an important trophic link transferring the macrophyte carbon to RKC. However, P. camtschaticus may also directly consume plant residues. Despite generally similar calculated trophic levels of decapod species, our isotopic data and literature data on the food composition of Paralithodes camtschaticus in the Barents Sea do not indicate significant RKC's competition with, and predation on, native species of crabs.

Restored kelp facilitates lobster recruitment but not other mid‐trophic macroinvertebrates

Abstract The patch dynamics of foundation species profoundly affects community assembly and thus has important implications for ecosystem restoration. However, it is unclear how restored kelp patches that vary in size and density will influence the establishment of mid‐trophic level (MTL) macroinvertebrates, a key functional group in coastal ecosystems. Artificial reefs with transplants of the canopy‐forming kelp, Ecklonia radiata, were used to quantify the effect of patch size and kelp density on the densities of MTL macroinvertebrates (primarily decapod crustaceans) and on the recruitment of an ecologically important and commercially valuable lobster species. Densities of MTL macroinvertebrates, which were dominated by hermit crabs, decreased with increasing patch size but responded inconsistently to kelp density. There was, however, an overall positive relationship between MTL macroinvertebrates and the density of small epifaunal grazers (a potential food source), along with a negative association with cover of understorey foliose algae. In contrast, the total abundance and density of lobster recruits was higher on larger reefs, and reefs with kelp had up to double the number of recruits relative to reefs with no kelp. After 12 months, most of the surviving lobster recruits occurred on reefs supporting low and medium densities of kelp. These results show that patchy reef substratum is effective in supporting high densities of some MTL macroinvertebrates, irrespective of kelp presence. Although conversely, larger reefs with restored kelp at natural – or even relatively low – densities appear critical to the recruitment of lobsters, which could motivate and provide positive feedback for kelp restoration projects in some locations. Patch dynamics may be used to support restoration efforts by helping to accelerate the recovery of key species and ecosystem services; however, trade‐offs will exist through different taxa responding to patch characteristics in different ways, some positive and some negative.

Individualism versus collective movement during travel

Collective movement may emerge if coordinating one’s movement with others produces a greater benefit to oneself than can be achieved alone. Experimentally, the capacity to manoeuvre simulated groups in the wild could enable powerful tests of the impact of collective movement on individual decisions. Yet such experiments are currently lacking due to the inherent difficulty of controlling whole collectives. Here we used a novel technique of experimentally simulating the movement of collectives of social hermit crabs (Coenobita compressus) in the wild. Using large architectural arrays of shells dragged across the beach, we generated synchronous collective movement and systematically varied the simulated collective’s travel direction as well as the context (i.e., danger level). With drone video from above, we then tested whether focal individuals were biased in their movement by the collective. We found that, despite considerable engagement with the collective, individuals’ direction was not significantly biased. Instead, individuals expressed substantial variability across all stimulus directions and contexts. Notably, individuals typically achieved shorter displacements in the presence of the collective versus in the presence of the control stimulus, suggesting an impact of traffic. The absence of a directional bias in individual movement due to the collective suggests that social hermit crabs are individualists, which move with a high level of opportunistic independence, likely thanks to the personal architecture and armour they carry in the form of a protective shell. Future studies can manipulate this level of armour to test its role in autonomy of movement, including the consequences of shell architecture for social decisions. Our novel experimental approach can be used to ask many further questions about how and why collective and individual movement interact.

Two new hermit crab species of Diogenes (Crustacea: Decapoda: Diogenidae) from Atlanto-Mediterranean coasts of Iberian Peninsula: Poleward migrants or merely overlooked indigenous species?

A new hermit crab species of the genus Diogenes with reddish‐orange cheliped, Diogenes erythromanus sp. nov., is described and illustrated based on specimens from the Mediterranean coasts of the Iberian Peninsula, southern Spain. In addition, a second morphotype originating from Mauritanian waters and morphologically very close to D. erythromanus sp. nov. is described as a different species, D. arguinensis sp. nov. The new species are here compared to morphologically similar congeners, especially to those inhabiting the same geographical range. Diogenes erythromanus sp. nov. is distinguishable from other Diogenes primarily by the shape and armature of the left cheliped, with a palm slightly higher than long, with a ridge of spines running along the proximal lower margin that continues with a series of spinose rows forming a central band parallel to the upper margin of the palm. The palm in D. arguinensis sp. nov. is longer than high and shows similar proximal ridge, but without central spinose ridge. The shape of the cheliped is also different in D. arguinensis sp. nov., with long dactylus, which is also flattened and twisted. Sequences from two mitochondrial and one nuclear genes, and comparative analyses with other available sequences for the genus, are also included. Molecular phylogenetic analyses support the morphological delimitation, with D. erythromanus sp. nov. and D. arguinensis sp. nov. forming a separate group, more related to other tropical species, which raises different possible explanations for its presence in the Iberian Peninsula.

First record of crab-eating mongoose (Herpestes urva formosanus) in coastal forest and use of anvils during predation on land hermit crabs in Taiwan

First record of crab-eating mongoose (Herpestes urva formosanus) in coastal forest and use of anvils during predation on land hermit crabs in Taiwan

Geographic distance, sedimentation, and substrate shape cryptic crustose coralline algal assemblages in the world's largest subtropical intertidal algal reef.

Algal reefs, concreted by crustose coralline algae (CCA), are the main biotic reefs in temperate waters but rare in the subtropics and tropics. The world's largest known intertidal algal reef in the subtropics is the Taoyuan Algal Reef (TAR) located in the northwestern coast of Taiwan. The biodiversity and ecology of the TAR are scarcely explored, and now the reef is imperiled by industrialization. Here, we document cryptic species of CCA in Taiwan, particularly the TAR, by sequencing the psbA genes of over 1800 specimens collected across Taiwan. We also examine the ecological background of the TAR by surveying its benthic composition and measuring its environmental parameters. Our data reveal that the TAR harbours a high diversity of cryptic CCA species (27 molecular operational taxonomic units, or mOTUs), many of which are potentially new to science (18 mOTUs) and/or endemic to the TAR (9 mOTUs). Comparing the CCA species inventory of the TAR with the rest of Taiwan shows that the TAR represents a unique hotspot of CCA taxa in the waters of Taiwan. Our analyses show that variation in the CCA assemblages in the TAR is associated with geographic distance, sedimentation, and substrate type (for example, reef vs. hermit crab shell), suggesting that dispersal limitation and contemporary environmental selection shape the CCA assemblages in the TAR. The data from this study can inform the monitoring of human impacts on the health of the TAR and contribute to our understanding of the ecological processes underlying algal reef development.

About the Cover

Next article FreeAbout the CoverPDFPDF PLUSFull Text Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinked InRedditEmailQR Code SectionsMoreThe cover image depicts the symbiotic relationship between the shell-forming sea anemone Stylobates calcifer sp. nov. (Yoshikawa & Izumi, 2022) and the hermit crab Pagurodofleinia doederleini (Doflein, 1902). The image shows the living states of the paratype specimens deposited in the National Museum of Nature and Science, Tsukuba, Japan, as NSMTCo 1795, collected from the Sea of Kumano off the coast of the Kumano Region of the Kii Peninsula, Honshu, Japan.In this issue (pp. 127–152), A. Yoshikawa, T. Izumi, T. Moritaki, T. Kimura, and K. Yanagi describe S. calcifer sp. nov. as a new carcinoecium-forming (CF) anemone species from the Pacific coast of Japan. The symbiotic association between hermit crabs and sea anemones is a classic example of mutualism in the sea. However, because CF relationships occur mainly on the deep-sea floor, records of the living state of the specimens are rare and limited. In addition to the difficulty of the specimen collection and sample preservation, the very thin, flat-concave shape, depending on the host shell, has led to the difficulty of the taxonomical examination of the Stylobates group.In collaboration with the Japanese Toba Aquarium, the authors conducted behavioral observations of this new species, focusing on feeding behaviors and interaction with the specific host hermit crab. Their observations suggest that this new sea anemone may feed on suspended particulate organic matter from the water column or the food residuals produced by hermit crab feeding. Moreover, when the sea anemone transfers to the new shell after the host hermit crab’s shell is changed, the sea anemone climbs up and settles down with its oral disk facing upward (the position shown in the cover photograph). These observations may lead to a new hypothesis that the upward-facing position of S. calcifer sp. nov. is an adaptation for feeding on suspended particulate organic matter from the water column. Their study represents what is perhaps the first observation of behavioral interactions of CF mutualism in the deep sea.Credits: Photo, Akihiro Yoshikawa, Atmosphere and Ocean Research Institute, University of Tokyo. Cover design: Olivia Kinker, University of Chicago Press. Next article DetailsFiguresReferencesCited by The Biological Bulletin Volume 242, Number 2April 2022 Published in association with the Marine Biological Laboratory Article DOIhttps://doi.org/10.1086/720918 Views: 438Total views on this site © 2022 The University of Chicago. All rights reserved.PDF download Crossref reports no articles citing this article.