Squat Lobster Research Articles

Living Along Distribution Margins: Differences in the Body and Biochemistry of Red Squat Lobster Morphotypes (Grimothea monodon) from the Humboldt Current System

Grimothea monodon, an important fishery resource in the Humboldt Current marine ecosystem (HCE), present two contrasting morphotypes (PM, pelagic morphotype; BM, benthic morphotype). The fishery management of G. monodon is focused on understanding only fishery aspects that apply to a limited area, and there are currently no studies that evaluate the nutritional status of these morphotypes. This study evaluated the biological performance of PM and BM, analyzing the body (size, CL; weight, W; condition factor, Kn) and biochemical condition (glucose, G; proteins, P; lipids, L; fatty acids, FAs). The results reveal that G. monodon showed differences in CL and W between morphotypes, with higher values in BM than PM. The Kn was different between morphotypes with a tendency of isometric growth. In turn, the G contents were higher in PM than BM, while the contents of P, L, and FAs showed an opposite tendency, with higher contents recorded in BM than PM. Our findings suggest that the Kn should be included to strengthen the biological parameters and their relationships used in fishery management models. Differences in the biochemical condition between morphotypes can be considered potentially adaptive, in response to the combined effect of environmental factors that vary in the HCE.

Integrative taxonomy reveals a new species of deep-sea squat lobster (Galatheoidea, Munidopsidae) from cold seeps in the Gulf of Mexico

The western Atlantic Ocean harbors a diverse fauna of squat lobsters, particularly in the family Munidopsidae. This study introduces Munidopsis sednasp. nov., a species only found in the Gulf of Mexico and the first species reported to be endemic to cold seeps in the western Atlantic. Our investigation incorporates morphological analyses including micro-CT scanning evidence, multilocus molecular phylogeny, and mtDNA phylogeography, as well as ecological data derived from in situ observations and geographic distribution patterns to substantiate the recognition of the new species. Shallow molecular divergences and multiple morphological differences differentiate the new species from its closest relative, M. longimanus (A. Milne-Edwards, 1880). Additionally, we explore the potential scenario for ecological speciation within this newly identified taxon and discuss its significance in the context of conservation efforts in the Gulf of Mexico.

Galatheoid squat lobsters (Crustacea: Decapoda: Anomura) from the epipelagic bottom of the Indian Exclusive Economic Zone, with descriptions of five new species

Galatheoid squat lobsters (Crustacea: Decapoda: Anomura) from the epipelagic bottom of the Indian Exclusive Economic Zone, with descriptions of five new species

Becoming a mother too early: The first record of the smallest ovigerous female of the deep-sea squat lobster Iridonida iris (A. Milne Edwards, 1880) (Decapoda: Munididae)

Becoming a mother too early: The first record of the smallest ovigerous female of the deep-sea squat lobster Iridonida iris (A. Milne Edwards, 1880) (Decapoda: Munididae)

A new species of Uroptychus Henderson, 1888 (Decapoda: Anomura: Chirostylidae) from a seamount in the South China Sea

A new species of the chirostylid squat lobster, Uroptychus ngae sp. nov. is described based on two specimens from the Zhongnan Seamount, north-central South China Sea. The new species can be distinguished from closely related species mainly by the shape of P2–4 propodi, and the spination of the P1 carpus and merus, the anterior branchial margin and the pterygostomial flap. The present paper is the first report of squat lobster from the seamounts in South China Sea. The present new species represents the first report of a squat lobster from the deep-sea seamounts in the South China Sea.

Diversity of squat lobsters on coral reefs in Guam, Mariana Islands, with the description of two new species and notes on their natural history

Diversity of squat lobsters on coral reefs in Guam, Mariana Islands, with the description of two new species and notes on their natural history

Establishment of a new subfamily for the parasitic isopod genus Pleurocryptella (Isopoda: Bopyridae), including recognition of epicaridium larval yolk sacs and description of a new genus and species of hyperparasite

Abstract External yolk sacs in free-living larvae of marine invertebrates are extremely rare, with all reported cases exhibiting yolk that is taken up through connection with the anterior alimentary canal. Herein, we confirm a novel yolk sac connected to the posterior end of the alimentary canal in the first larval stage of species in the bopyrid isopod genus PleurocryptellaBonnier, 1900, all known as ectoparasites in the branchial chambers of squat lobsters. Pleurocryptella poseidon Williams & Boyko sp. nov. infesting the munidopsid Galacantha bellis Henderson, 1885 in the Arabian Sea, is described on the basis of adults and larvae. In common with conspecifics, the new species exhibits a suite of putative “primitive” characters including the presence of oostegites on the sixth and seventh pereomeres of females and maxillipeds and articulated uropods in males. Pleurocryptella poseidon Williams & Boyko sp. nov. differs from other species of Pleurocryptella by characters of body shape, antennae, oostegite 1, pleon, and uropods of females and midventral tubercles, pleomeres, and pleopods of males. The epicaridium larvae have a large posterior, external yolk sac and segmented maxillipeds, a unique set of characters within Epicaridea. In addition to larval and adult characters, molecular data (COI) indicate that the genus is distinct from other members of Bopyridae, so we erect the new subfamily Pleurocryptellinae for it. Pleurocryptella poseidon Williams & Boyko sp. nov. bears a new genus and species of hyperparasitic isopod that is herein described based on its cryptoniscus stage. A review of epicaridium larval morphology and a key to the species of Pleurocryptella are provided.

Exoskeletal Trade-off between Claws and Carapace in Deep-sea Hydrothermal Vent Decapod Crustaceans.

Limitations on energetic resources create evolutionary trade-offs, prompting us to investigate if investment in claw strength remains consistent across crustaceans living in diverse habitats. Decapod crustaceans living in deep-sea hydrothermal vents are ideal for this study due to their extreme environment. In this study, we investigated whether decapods (blind crab Austinograea sp. and the squat lobster Munidopsis lauensis) living in deep-sea hydrothermal vents prioritize investing in strong claws compared to the carapace, like coastal decapods. We analyzed exoskeleton morphology, mechanical properties, structures, and elemental composition in both the carapace and claws of four Decapoda species (two each from Brachyura and Anomura infraorders) in vent and coastal habitats. Coastal decapods had ∼4-9 times more teeth on their claw cutting edge than the vent species. Further, only the coastal species exhibited higher firmness in their claws than in their carapaces. Each infraorder controlled exoskeletal hardness differently: Brachyura changed the stacking height of the Bouligand structure, while Anomura regulated magnesium content in the exoskeleton. The vent decapods may prioritize strengthening their carapace over developing robust claws, allocating resources to adapt to the harsh conditions of deep-sea hydrothermal vents. This choice might enhance their survival in the extreme environment, where carapace strength is crucial for protecting internal organs from environmental factors, rather than relying on the powerful claws seen in coastal decapods for a competitive advantage.

DNA barcoding and morphology revealed the existence of seven new species of squat lobsters in the family Munididae (Decapoda, Galatheoidea) in the southwestern Pacific.

Specimens of squat lobsters belonging to the family MunididaeAhyong et al., 2010, representing the genera Garymunida Macpherson & Baba, 2022, Trapezionida Macpherson & Baba, 2022 and Typhlonida Macpherson & Baba, 2022, were collected during several cruises around New Caledonia and Papua New Guinea, Southwest Pacific. The integrative study of these specimens revealed the presence of one new species in Garymunida, five in Trapezionida and one in Typhlonida. We describe and illustrate these new species, providing some new data on the taxonomy of several rare or scarcely studied species of Trapezionida. Molecular data from different markers (mitochondrial and nuclear) was also included, based on data availability, to support the taxonomic status of different species. Finally, a key to species for each genus is also provided.

Faunal community of a new hot vent field on the Amami Rift

Abstract Deep-sea hydrothermal vents host chemosynthesis-based ecosystems inhabited chiefly by specially adapted animals that do not live anywhere else, and depth has been shown to be a major driver of species composition at vents around Japan. Though the Ryukyu region in southern Japan is home to many hot vents, only two – Minami-Ensei Knoll and Yoron Hole – have been found shallower than 1000 m. Here, we report the discovery of a new vent field on the Amami Rift northwest off Amami Ōshima at 630 m deep. A total of 29 macrofaunal species were recorded from Amami Rift, including 19 vent specialists. Comparison of species composition across the three shallow Ryukyu vents revealed only three shared species, highlighting that all three display distinct community structure. Amami Rift exhibits distinct zonation patterns and is generally more similar to Minami-Ensei than Yoron Hole, but the presence of key taxa such as the sulphide worm Paralvinella and the mussel ‘Bathymodiolus’ platifrons as well as the absence of the symbiotic squat lobster Shinkaia and the limpet Lepetodrilus exemplify its difference with Minami-Ensei. Furthermore, the non-vent specific predators seen in these two sites were completely different. Overall, the Amami Rift vent field can be considered a shallow vent with a unique set of fauna, warranting future research on the mechanisms shaping disparate macrofaunal diversity between nearby shallow vents such as Amami Rift and Minami-Ensei. The unusual geological setting of Amami Rift at the converging point of Okinawa Trough and Ryukyu Arc may influence fluid chemistry to drive such differences.

Bialorastins A–F, highly oxygenated and polycyclic andrastin-type meroterpenoids with proangiogenic activity from the deep-sea cold-seep-derived fungus Penicillium bialowiezense CS-283

Six new highly oxygenated and polycyclic andrastin-type meroterpenoids, namely, bialorastins A–F (1–6), were discovered from the culture of Penicillium bialowiezense CS-283, a fungus isolated from the deep-sea cold seep squat lobster Shinkaia crosnieri. The planar structures and absolute configurations of these compounds were determined by detailed analysis of spectroscopic data, single crystal X-ray diffraction, and TDDFT-ECD calculations. Structurally, bialorastin A (1) represents a rare 17-nor-andrastin that possesses an unusual 2-oxaspiro[4.5]decane-1,4-dione moiety with a unique 6/6/6/6/5 polycyclic system, while bialorastin B (2) is also a 17-nor-andrastin featuring a gem-propane-1,2-dione moiety. Additionally, bialorastins C–E (3–5) possess a 6/6/6/6/5/5 fused hexacyclic skeleton, characterized by distinctive 3,23-acetal/lactone-bridged functionalities. All isolated compounds were evaluated for their proangiogenic activities in transgenic zebrafish. Compound 3 exhibited significant proangiogenic activity, which notably increased the number and length of intersegmental blood vessels in model zebrafish in a dose-dependent manner at concentrations of 20 and 40 μM. On a molecular scale, the tested compounds were modeled through molecular docking to have insight into the interactions with the possible target VEGFR2. Mechanistically, RT-qPCR results revealed that compound 3 could promote angiogenesis via activating VEGFR2 and subsequently activating the downstream PI3K/AKT and MAPK signaling pathways. These findings indicate that 3 could be a potential lead compound for developing angiogenesis agents.

New records of introduced species in the Mediterranean Sea (November 2023)

This collective article presents new information about 15 introduced taxa belonging to five phyla: one Rhodophyta, one Chlorophyta, one Mollusca, one Annelida, two Arthropoda, and nine Chordata (one Ascidiacea and eight Osteichthyes). The records refer to eight Mediterranean countries and extend from the Alboran Sea to the Levantine Sea as follows: Spain: first record of the African hind Cephalopholis taeniops for the Alboran Sea, and a further record of the Monrovia surgeonfish Acanthurus monroviae, extending its distribution northwards in the Western Mediterranean. Italy: an additional record of the squat lobster Scyllarus subarctus based on its nisto stage, new records of the lionfish Pterois miles in the north-western Ionian Sea, first records of the bivalve Fulvia fragilis for the Italian Adriatic coast, and a record of the amphipod Ptilohyale littoralis in the northern Adriatic Sea, also representing the first report for the Mediterranean Sea. Montenegro: first record of the non indigenous ascidian Ciona robusta. Albania: first record of the red cornetfish Fistularia petimba. Greece: first record of the cryptogenic polychaete Alitta succinea in association with ship fouling, suggesting the possibility of a non-indigenous origin of Mediterranean populations of this species, and first record of the Seychelles dragonet Synchiropus sechellensis for the Saronikos Gulf. Türkiye: first record of the red alga Womersleyella setacea, report of an abundant population of the Indian twospot cardinalfish Cheilodipterus novemstriatus in the Turkish Aegean Sea, and first record of Synodus randalli, also corresponding to the first report for the Mediterranean Sea. Syria: first record of the blenny Istiblennius cf. meleagris. Israel: report of an algal bloom of the green alga Codium parvulum, and first record of Synchiropus sechellensis.

Freshwater decapod crustaceans from the state of Minas Gerais, Brazil: species composition and distribution.

Brazil contains about 5% (~120 spp.) of the total known species of freshwater decapods. Information on the occurrence of freshwater decapod species in the state of Minas Gerais is dispersed and much of this remains unpublished. We hereby propose to present the first inventory of freshwater decapods from the state, based on data compiled from publications and scientific collections and obtained from fieldwork in the state. Eleven species of freshwater decapods were recorded in Minas Gerais, including three species of crabs (Trichodactylidae), seven of shrimps (Palaemonidae) and one species of freshwater squat lobster (Aeglidae), classified into three infraorders, three families, and four genera. The genus Macrobrachium C.S. Bate, 1868 comprised most of the decapod records. The reduced number of species in relation to coastal states is related, at least in part, to the absence of amphidromic species. Environmental degradation and the construction of dams in several watersheds may be possible causes of this absence. The records obtained from surveys carried out in national parks situated in Minas Gerais and its surroundings indicate the importance of these areas for the conservation of decapod fauna in the state.

Genetic divergence and migration patterns of a galatheoid squat lobster highlight the need for deep-sea conservation.

Information on genetic divergence and migration patterns of vent- and seep-endemic macrobenthos can help delimit biogeographical provinces and provide scientific guidelines for deep-sea conservation under the growing threats of anthropogenic disturbances. Nevertheless, related studies are still scarce, impeding the informed conservation of these hotspots of deep-sea biodiversity. To bridge this knowledge gap, we conducted a population connectivity study on the galatheoid squat lobster Shinkaia crosnieri - a deep-sea foundation species widely distributed in vent and seep ecosystems in the Northwest Pacific. With the application of an interdisciplinary methodology involving population genomics and oceanographic approaches, we unveiled two semi-isolated lineages of S. crosnieri with limited and asymmetrical gene flow potentially shaped by the geographic settings, habitat types, and ocean currents - one comprising vent populations in the Okinawa Trough, with those inhabiting the southern trough area likely serving as the source; the other being the Jiaolong (JR) seep population in the South China Sea. The latter might have recently experienced a pronounced demographic contraction and exhibited genetic introgression from the Okinawa Trough lineage, potentially mediated by the intrusion of the North Pacific Intermediate Water. We then compared the biogeographic patterns between S. crosnieri and two other representative and co-occurring vent- and seep-endemic species using published data. Based on their biogeographical subdivisions and source-sink dynamics, we highlighted the southern Okinawa Trough vents and the JR seep warrant imperative conservation efforts to sustain the deep-sea biodiversity in the Northwest Pacific.

Development ofmarine biodiversity database (BISMaL) to enable estimations past habitat conditions formarine life inthe northwestern Pacific.

Global activities involving the collection of marine biodiversity information have provided a large amount of biological observation records that cover various spatiotemporal areas. To predict biological responses or distribution changes in response to environmental changes by using these observation records, it is essential to analyze not only the current marine physicochemical environmental conditions but also the past conditions when the organisms were observed. We developed a new function to estimate the past marine environmental conditions for the observation records in our marine biodiversity database (Biological Information System for Marine Life: BISMaL) and examine whether the database can reliably estimate thermal habitats for both benthic and planktonic marine organisms. For the benthic squat lobster Shinkaia crosnieri, the estimated and observed in situ temperatures were similar to each other. For the planktonic chaetognaths Krohnitta pacifica and K. subtilis, the estimated temperatures showed clear seasonal changes specific to their distribution areas. These results indicated that BISMaL can reliably provide past habitat conditions regardless of planktonic or benthic lifestyles. BISMaL, which provides both biological observations and estimated past environmental conditions through web services, could lower the barrier to data access and use and make data-driven science available not only for data scientists but also for various marine scientists, such as taxonomists, ecologists and field scientists. Database URL: https://www.godac.jamstec.go.jp/bismal/e/.

New record of two species of munidid squat lobster (Decapoda: Anomura) from the North-West Pacific off Japan.

Two species of munidid squat lobsters are newly reported from the North-West Pacific off Japan based on material collected by the recent cruise of R/V Kaimei (KM20-10C cruise) of the Japan Agency for Marine-Earth Science and Technology, exploring seamounts in the marine protected area (MPA): Gonionida kaimei n. sp. and Trapezionida psylla (Macpherson, 1994). Gonionida kaimei n. sp. closely resembles G. tangaroa (Ahyong, 2007) and G. rubrimana (Ahyong, 2007), but morphological characters and living colouration differentiate the new species from the latter two species. Genetic analysis using two molecular markers (mitochondrial COI and 16S rRNA genes) also supports the recognition of the new species. Trapezionida psylla has been recorded from the South-West Pacific, and thus the present material greatly extends the geographic range of the species to the North-West Pacific. The identity of the present specimens is also confirmed by the genetic data, as well as the morphological evidence. This study contributes to documenting the benthic invertebrate fauna of the Japanese MPA.

On some commensal anomuran and brachyuran crabs (Crustacea: Decapoda) off Visakhapatnam, Northwestern Bay of Bengal.

Commensal anomuran and brachyuran crabs were collected from extensive exploratory surveys on rocky areas where soft corals, sea anemones and sponges are found off the Visakhapatnam coast. The present study includes nine species of commensal decapod crustaceans, comprising four porcellanid crabs (Petrolisthes lamarckii (Leach, 1820), Porcellanella triloba White, 1852, Polyonyx hendersoni Southwell, 1909 and Pisidia gordoni (Johnson, 1970)), one squat lobster (Allogalathea elegans (Adams, 1847) and four brachyuran crabs (Dorippoides facchino (Herbst, 1785), Quadrella coronata Dana, 1852, Quadrella maculosa Alcock, 1898 and Sphenomerides trapezioides (Wood-Mason & Alcock, 1891). Allogalathea elegans, Polyonyx hendersoni, Pisidia gordoni, Quadrella coronata and Quadrella maculosa are new records from off Visakhapatnam. The porcellanid crabs are associated with the sea pen Pteroeides esperi, desmosponges and black soft corals Antipathes sp. whereas the squat lobster was associated with the soft coral Dendronephthya sp. The brachyuran crabs were observed in association with Antipathes sp. Here, we provide details on the morphology, distribution, habitat and commensalism of decapod crustaceans studied.

The Red Squat Lobster Pleuroncodes monodon in the Humboldt Current System: From Their Ecology to Commercial Attributes as Marine Bioresource.

This study focused on gathering available information on Pleuroncodes monodon, a widely distributed crustacean in the Humboldt Current System. Off the Chilean coast, this species presents benthic habits and constitutes the main resource of the industrial crustacean fishery; many studies have been carried out on its life cycle during the last century. In contrast, off the coast of Peru, this species exhibits mainly pelagic habits, with latent information gaps on aspects of its life history and no commercial fishery activities, such as catching, taking or harvesting from the marine environment. P. monodon is an ecologically important species, as a source of energy for its predators, which include invertebrates, birds, marine mammals and fish of commercial interest. Thus, P. monodon seems to play a key role in this ecosystem, mainly as an intermediate link between top predators and the first links in the food chain. In addition, this species presents various adaptation strategies to the changing oceanographic parameters of the areas it inhabits, even tolerating hypoxic environments and great depths in order to avoid being predated. Likewise, from an economic viewpoint, it has a high commercial value as a marine bioresource with great potential in the pharmaceutical and food industries. Considering this, more studies must be carried out to corroborate the biological, ecological, and fishing importance of this species in order to generate efficient management measures and ensure a sustainable fishery.

Variation in epibiotic bacteria on two squat lobster species of Munidopsidae.

The relationships between epibiotic bacteria on deep-sea hosts and host lifestyle factors are of particular interest in the field of deep-sea chemoautotrophic environmental adaptations. The squat lobsters Shinkaia crosnieri and Munidopsis verrilli are both dominant species in cold-seep ecosystems, and they have different distributions and feeding behaviors. These species may have evolved to have distinct epibiotic microbiota. Here, we compared the epibiotic bacterial communities on the M. verrilli carapace (MVcarapace), S. crosnieri carapace (SCcarapace), and S. crosnieri ventral plumose setae (SCsetae). The epibiotic bacteria on SCsetae were dense and diverse and had a multi-layer configuration, while those on MVcarapace and SCcarapace were sparse and had a monolayer configuration. Chemoautotrophic bacteria had the highest relative abundance in all epibiotic bacterial communities. The relative abundance of amplicon sequence variant 3 (ASV3; unknown species in order Thiotrichales), which is associated with sulfide oxidation, was significantly higher in SCsetae than MVcarapace and SCcarapace. Thiotrichales species seemed to be specifically enriched on SCsetae, potentially due to the synthetic substrate supply, adhesion preference, and host behaviors. We hypothesize that the S. crosnieri episymbionts use chemical fluxes near cold seeps more efficiently, thereby supporting the host's nutrient strategies, resulting in a different distribution of the two species of squat lobster.

New records of the squat lobster genus Munidopsis Whiteaves, 1874 (Crustacea, Decapoda, Munidopsidae) from the deep sea off Taiwan.

Two species of the squat lobster family Munidopsidae, Munidopsisalbatrossae Pequegnat & Pequegnat, 1973 and M.pycnopoda Baba, 2005, are reported from Taiwan for the first time based on specimens collected from lower bathyal depths. The Taiwanese material of M.pycnopoda also represents the first record of the species from the Pacific Ocean and greatly extends this species' geographical range from the western Indian Ocean to western Pacific. The giant Munidopsis specimen from Taiwan is identified as M.albatrossae mainly by DNA barcoding even though M.albatrossae and M.aries (A. Milne-Edwards, 1880) are both morphologically and genetically extremely similar.