Hermit Crab Species Research Articles

Morphological and Molecular Evidence for the Identity of Two Land Hermit Crabs Coenobita longitarsis De Man, 1902 and C. pseudorugosus Nakasone, 1988 (Crustacea: Decapoda: Anomura: Coenobitidae).

Two species of land hermit crabs, Coenobita longitarsis De Man, 1902 and C. pseudorugosus Nakasone, 1988 were described based on female specimens from Maluku, Indonesia and specimens from Cebu, the Philippines, respectively. However, no confirmed records of either species have been reported since their original descriptions. In this study, we examined specimens with typical morphological characters of C. longitarsis from Papua New Guinea and C. pseudorugosus from the Philippines and Indonesia, further supported by the analyses of the DNA barcoding marker, cytochrome oxidase subunit I (COI). The characters of male C. longitarsis are provided for the first time, with coxae of male fifth pereiopods subequal, without sexual tubes developed. Their slender morphology is suggested to be an adaptation to utilize native terrestrial snail shells in inland forests, which may also explain its rarity. Coenobita pseudorugosus is very similar to C. rugosus H. Milne Edwards, 1837, but can be distinguished by the adult sizes, as well as the morphology of sexual tubes of male fifth pereiopods and propodus of left third pereiopod. Morphological variation and the fresh coloration of C. longitarsis and C. pseudorugosus are also provided in this study.

A new species of the genus Eutrichopagurus Komai, 2015 (Crustacea: Decapoda: Anomura: Paguridae) from a submarine cave in the Ryukyu Islands, southwestern Japan

A new hermit crab species of the family Paguridae is described on the basis of two male specimens from Hedo Dome, a submarine cave located on the north coast of Okinawa Island, Ryukyu Islands, southwestern Japan. The assignment of the new species to the genus Eutrichopagurus Komai, 2015 is based on the structure of the gills and right male sexual tube, the article 3 of the antennular peduncle with a prominent tuft of setae on the dorsodistal margin, and the posterior lateral margins of the telson each bearing a prominent tuft of setae. Among two known congeners, Eutrichopagurus crassoculus n. sp. may be closer to the type species of the genus, E. shirakawai Komai, 2015, in having greatly reduced corneas, basally bearing sparse setae, and no small corneous spines or spiniform setae on the dorsal surface of the meri of the ambulatory legs, but is distinguishable by the morphology of the ocular peduncles, ocular acicle, antennular peduncle, and chelipeds.

A new species of hermit crab of the genus Pagurus Fabricius, 1775 (Crustacea: Anomura: Paguridae) from north-western Africa

One male and two female specimens of an undescribed species of the heterogeneous hermit crab genus Pagurus Fabricius, 1775, were found during the study of the collections of the Oceanographic Institute of Cádiz, containing specimens from African and European coasts collected during the scientific cruises carried out between in years 2008-2013. The new species is named Pagurus pectinidactylus n. sp., in reference to the presence of a well-developed toothless pectinate masticatory border in the dactylus of the left cheliped, composed by a row of tightly placed bristles forming a brush-like structure. The new species is compared to morphologically similar congeners, especially those that are genetically closest. Molecular phylogenetic analyses support the morphological delimitation, with P. pectinidactylus n. sp. forming a separate clade, more closely related to a group of South African species belonging to the Pagurus anachoretus group.

Study on Shell Utilization Pattern of Two Sympatric Hermit Crab Species on the Rocky Intertidal Region of Veraval, Gujarat, India

The present study illustrates the shell utilization and resource partitioning of two sympatric hermit crab species Clibanarius rhabdodactylus and Clibanarius ransoni with reference to gastropod shell species (shell shape), shell size and shell availability. Specimens were collected from January to March 2021 and hermit crab weight and shield length were measured. The gender of occupant hermit crab was identified and categorised into male, non-ovigerous female and ovigerous female. Gastropod shells were identified and different morphological parameters like shell length, shell aperture length and width, shell volume and dry weight were measured. The population of C. rhabdodactylus and C. ransoni was female biased with male: female ratio being 1:1.93 and 1:1.25 respectively. Clibanarius rhabdodactylus and C. ransoni were occupying 29 species and 28 species of gastropod shells respectively among which > 75% occupied shells were comprised of Cerithium caeruleum, Lunella coronata, Turbo bruneus, Tenguella granulate and Pollia undosa. Both the Clibanarius species were showing a high overlap in their intertidal distribution as well as gastropod shell use pattern. Cerithium caeruleum was found to occur in high abundance as compared to other gastropod species in the study area which may also influence the shell utilization of hermit crab species. Males and non-ovigerous females of the hermit crab species utilized almost all shell species, while ovigerous females used only a few shell species. Significant relationship was observed between different morphological parameters of the occupant crab species and occupied shells. Shell partitioning was evident between hermit crab sexes as well as reproductive stages on the basis of occupied shells of different species, shapes, and sizes. The present study revealed shell occupation pattern of C. rhabdodactylus and C. ransoni is highly influenced by the diversity, morphology and availability of gastropod shells in the study area.

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.

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.

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.

Three new species of pagurid hermit crabs (Decapoda: Anomura: Paguroidea) from the Northern Mariana Islands, Micronesia.

We describe three new species of hermit crab of the pagurid genera, Catapagurus A. Milne-Edwards, 1880, Nematopagurus A. Milne-Edwards Bouvier, 1892 and Pagurixus Melin, 1939, on the basis of material collected during the scientific cruise to the Northern Mariana Islands conducted by the U.S. National Oceanographic and Atmospheric Administration (NOAA) in 2015. Catapagurus tenuilamina n. sp., referred to the C. ensifer Henderson, 1893 species group, appears close to C. granulatus Edmondson, 1951, but differs from the latter in the more slender ultimate article of the antennular peduncle, more slender dactyli of pereopods 2 and 3, and the possession of two dorsal subdistal spines in the meri of the pereopods. Nematopagurus marianicus n. sp. resembles N. gardineri Alcock, 1905 and N. lewinsohni Trkay, 1986, but is distinguished from the latter two by the characteristic dense setation on the upper part of the left cheliped carpus and by the elongate dactyli of pereopods 2 and 3 that lack a row of bristle-like setae on the dorsal margins. Pagurixus eminens n. sp. is referred to the P. boninensis Melin, 1939 species group and appears closest to P. annulus Komai Poupin, 2013, but is differentiated from the latter in the shape and ornamentation of the right coxa of pereopod 5 in the male as well as details of the colour pattern on the chelipeds and ambulatory legs. Partial sequences of the mitochondrial 16S rRNA gene from the three new species were sequenced and deposited in the GenBank database for future genetic and phylogenetic study.

Coexistence of similar species: evidence of a resource and microhabitat sharing in two intertidal hermit crab species

Coexistence of similar species: evidence of a resource and microhabitat sharing in two intertidal hermit crab species

Diogenes matabiru, a new species of hermit crab from Lombok Island, Indonesia (Crustacea, Decapoda, Anomura, Diogenidae).

A new species of hermit crab, Diogenes matabiru, is described and illustrated on the basis of the specimens collected from mangrove environment in the eastern Lombok Island, Indonesia. This new species is related to D. pallescens Whitelegge, 1897 but differs in the shape of cheliped, telson and coloration in life. A key to the species of the genus Diogenes from Indonesia is also provided.

Downscaling hermit crab-gastropod network to demographic groups unveils recurrent patterns

We studied the hermit crab–shell interaction network of rocky shores in South Brazil using both community and populational (demographic groups) approaches which evaluated both inter and intraspecific perspectives. The community was composed of six hermit crab species and 33 gastropod shell species. We found a recurrent pattern in which the network structure was characterized by a modular and specialized pattern. The specialization at the species level varies in the community species and for ontogenetic groups. The configuration of the modules changed when switching from community to populational approaches, consisting of three and four modules, respectively. Resource partitioning must be a very important feature in these systems due to both the specific and demographic needs of each group. Our results reveal a pattern in which these types of interactions are modular and specialized, with those patterns being uncommon for non-mutualistic interactions in hermit crab-gastropod networks. The analyses showed difference in the network metrics when considering intra and interspecific perspectives. The mandatory nature of these interactions and the resource dynamics of the gastropod shells when occupied by hermit crabs may partially explain the patterns found for these unique interactions.

First report of a hermit crab Clibanarius longitarsus (De Haan, 1849) (Crustacea: Anomura) from sunderbans, India

Hermit crabs play a crucial role in the mangrove ecosystem; being scavenger in nature, they help quickly remove dead materials from soil. Hermit crabs belong to the Decapoda and superfamily Paguridae of the subphylum Crustacea. In India a total of 114 species of hermit crabs have been recorded, of which 20 species are reported so far from West Bengal. During the recent survey at Sunderban Biosphere Reserve, a hermit crab Clibanarius longitarsus De Han, 1849 was recorded, which is not hitherto reported from West Bengal. Detailed characters of the species along with the list of hermit crabs reported from West Bengal are given in this work.

Local olfactory interneurons provide the basis for neurochemical regionalization of olfactory glomeruli in crustaceans.

The primary olfactory centers of metazoans as diverse as arthropods and mammals consist of an array of fields of dense synaptic neuropil, the olfactory glomeruli. However, the neurochemical structure of crustacean olfactory glomeruli is largely understudied when compared to the insects. We analyzed the glomerular architecture in selected species of hermit crabs using immunohistochemistry against presynaptic proteins, the neuropeptides orcokinin, RFamide and allatostatin, and the biogenic amine serotonin. Our study reveals an unexpected level of structural complexity, unmatched by what is found in the insect olfactory glomeruli. Peptidergic and aminergic interneurons provide the structural basis for a regionalization of the crustacean glomeruli into longitudinal and concentric compartments. Our data suggest that local olfactory interneurons take a central computational role in modulating the information transfer from olfactory sensory neurons to projection neurons within the glomeruli. Furthermore, we found yet unknown neuronal elements mediating lateral inhibitory interactions across the glomerular array that may play a central role in modulating the transfer of sensory input to the output neurons through presynaptic inhibition. Our study is another step in understanding the function of crustacean olfactory glomeruli as highly complex units of local olfactory processing.

New hermit crabs (Paguroidea, Anomura) from the Eocene of Huesca, Spain

A new genus and two new species of fossil hermit crabs (Anomura, Paguroidea) are described from the southern Pyrenean basins (Huesca, NE Spain). Parapetrochirus nov. with P. robustus n. gen., n. sp., as type species, comes from the lower Eocene (Ypresian) Roda Formation. It preserves both chelipeds exhibiting a notable heterochely, a larger left cheliped and a concavity without granulation in the inner upper portions. Eocalcinus gerardbretoni n. sp. comes from the highest levels of the Arguis Formation (Priabonian) in Yeste locality. This species is characterized by a hemispherical outline and a sinuous lower margin of the chela, which differs from the type species of the genus. The cheliped morphology of such species allows inclusion in the families Diogenidae and Calcinidae, respectively. Fossil paguroids are relatively rare in the Eocene of Spain, therefore, the description of these two new taxa increases the known diversity of this group. Parapetrochirus robustus n. gen., n. sp. inhabited siliciclastic substrates within a prodelta environment and E. gerardbretoni n. sp. was collected from the last levels of coral rudstones just below the continental influence of Yeste-Arrés Formation.

Effect of salinity on survival and emigration behaviour during the sea-to-land transition of three terrestrial hermit crab species (Decapoda: Anomura: Coenobitidae) under laboratory conditions

Effect of salinity on survival and emigration behaviour during the sea-to-land transition of three terrestrial hermit crab species (Decapoda: Anomura: Coenobitidae) under laboratory conditions

Crab diversity as support for ecotourism activities in Pejarakan Mangrove Forest, Buleleng, Bali, Indonesia

Abstract. Ginantra IK, Muksin IK, Joni M. 2021. Crab diversity as support for ecotourism activities in Pejarakan Mangrove Forest, Buleleng, Bali, Indonesia. Biodiversitas 22: 4139-4145. This research aims to determine the diversity of crabs to support ecotourism activities in the coastal mangrove forest of Pejarakan Buleleng. Sampling of crabs was carried out using the square method, as many as 23 squares were spread over three mangrove zones, namely the front zone, the middle zone, and the rear zone. The number of individual crustacean species in each square plot was counted. Crab identification is based on morphological characters (shell color, claw shape, body-color, body size). Habitat use activities are observed directly. The diversity of crabs was calculated using the Shannon-Wiener diversity index. The results showed that in the coastal mangrove area of Pejarakan Buleleng, there were 11 species of crabs (9 species of crabs and 2 species of hermit crabs). Species diversity is in the medium category (index 2.25) and evenness index is high (E = 0.93, mangrove conditions are stable). The seaward mangrove zone shows a higher diversity of crab species than the middle zone and the rear zone. The species of crabs that are quite abundant in the three zonings are Uca vocans, Chiromanthes sp., and Coenobita sp. Characteristics of crabs, activities, habitat use in mangrove zoning are attractions for ecotourism activities.

Increased potential for shell competition among hermit crabs (Pagurus beringanus and Pagurus granosimanus) in the rocky intertidal

AbstractWe examined the prevalence and shell use of two species of hermit crabs (Pagurus granosimanus and Pagurus beringanus) in exposed and protected microhabitats at five sites in the rocky temperate intertidal on San Juan Island, Washington, to compare present habitat partitioning and potential interspecific competition to that reported nearly 50 years ago. We found that, in contrast to previous findings, the two species of hermit crabs overlapped extensively at some sites, typically those with less wave action. While the hermit crabs typically inhabited certain types of shells significantly more than others, and that use was congruent across microhabitats and species of hermit crabs at the same site, the dominant domicile differed substantially across sites. We provide a more complete ranking of shell use than previous authors and note site-specific dominant shell use. We conclude that previous habitat partitioning by depth may have weakened at protected sites. We hypothesize that increasing temperatures have caused P. granosimanus to expand its range deeper into the intertidal, which may increase the degree of interspecific competition for shells at the edge of the species’ tidal height range, where they overlap. Whether the habitat shift by this hermit crab is due to recent alterations in climate (particularly elevated temperatures, ocean acidification and lower local open ocean salinity) is unknown, but warrants further study.

Social conquest of land: Sea-to-land changes in shell architecture and body morphology, with consequences for social evolution

Architecture, like nests, burrows, and other types of fortresses, may have played an important role in the evolution of social life on land. However, few studies have examined architecture in organisms that transitioned from sea to land to test how and why architectural and morphological changes might have jointly impacted social evolution. Here I contrasted the shell architecture and body morphology of two of the phylogenetically most closely-related land versus sea species of hermit crab (the terrestrial hermit crab, Coenobita compressus, and the marine hermit crab, Calcinus obscurus), as well as the original builder of their shells (the gastropod, Nerita scabricosta). In contrast to the shells of gastropods and marine hermit crabs, only the shells of terrestrial hermit crabs were architecturally remodeled, with no columella inside for the occupants to grip upon to resist eviction. The bodies of terrestrial hermit crabs were also significantly more exposed outside the enlarged openings of their remodeled shells, whereas the substantially smaller-bodied marine hermit crabs were safeguarded deep within the recesses of their unremodeled shells. Ultimately, these changes in shell architecture and body morphology likely had consequences for social evolution on land, making conspecifics not only more dependent upon one another for homes, but also potentially easier to evict. Further changes in claw shape on land (with the claws of terrestrial hermit crabs becoming shorter, wider, and thicker) may have evolved to help offset their heightened danger of social eviction, acting as a more effective door against conspecifics.

Biodiversity of hermit crabs in Odisha, east coast and their distribution in other coastal states of India

Hermit crabs are one among the least studied group of the animal kingdom. The diversity of hermit crabs of entire Odisha coast was studied for the first time. Collected primary data and secondary data were compiled to prepare an updated checklist of hermit crabs of Indian coast. A total of seven species of hermit crabs were recorded during the field surveys along Odisha coast. The compilation of secondary data with present primary data revealed occurrence of 114 species of hermit crabs belonging to 27 genera and six families along the Indian coast. Diogenidae was identified as the dominant family. The diversity of hermit crabs is high in the west coast (73 species) as compared to the east coast (65 species). Maximum species diversity is recorded in Tamil Nadu (53 species), Kerala (50 species) and in Andaman & Nicobar Islands (46 species). Twenty threes species of hermit crabs inhabit the coastal ecosystems of Odisha. The present study also reports the occurrence of Clibanarius infraspinatus for the first time from Odisha thus, extending its distributional range along the Indian coast. Among the reported 114 species, only 61 species are included in GBIF with Indian distribution whereas occurrence data is not available for 11 species and 42 species are not likely distributed along Indian coast. The findings of the present study support the occurrence of 61 species (included in Global Biodiversity Information Facility) along the Indian coast and suggest that the occurrence and distribution of remaining 53 species can be confirmed after conducting extensive field surveys.

Resource partitioning and adequacy among ontogenetic groups in a hermit crab and gastropod shell network

In ecology, interaction networks allow the investigation of how interactions among species affect community structure and functioning. The structure of interaction networks can be nested and/or modular. Ecologically, the nested structure minimizes competition and increases the number of coexisting species, creating high diversity, while the modular structure occurs when there are non-overlapping groups of highly interacting consumer-resource species. Despite the importance of gastropod shells to hermit crabs, currently, few studies explored the structure of hermit crabs communities through a resource-usage perspective. Therefore, network analyses appear as an important tool to unveil how the use of empty shell as a resource rules hermit crabs communities through competition among species and rules hermit crabs populations through competition among distinct ontogenetic groups. This study investigated the resource usage pattern of empty gastropod shells by distinct ontogenetic stages of the hermit crab Calcinus tibicen from two different locations, using a network approach and the “Shell Adequacy Index” (SAI) analysis. The present results show that the interaction network between ontogenetic groups and gastropod shells was non-nested and modular and the SAI reflected the differences between males and ovigerous females in both locations, regarding shell size adequacy. We suggest that the modular structure may be a result of resource partitioning, which, in turn, is favored in habitats with a high degree of heterogeneity. The modular network structure may indicate habitat heterogeneity and resource partitioning. Future studies including other hermit crab species from the same areas should help determine how shells are partitioned interspecifically.