Crustacean

Guides

Petrolisthes armatus
Green Porcelain Crab
Petrolisthes armatus, commonly known as the green porcelain crab, is a small porcellanid crab native to the southwestern Atlantic, particularly Brazil. The species has established invasive populations along the southeastern United States coast, where densities can exceed 30,000 individuals per square meter. Genetic studies confirm it as a single monophyletic species with exceptional geographic range spanning the Atlantic and eastern Pacific. It is frequently parasitized by the bopyrid isopod Aporobopyrus curtatus, which causes parasitic castration.
invasive-species filter-feeder parasite-host intertidal porcelain-crab oyster-reef symbiosis planktonic-larvae visual-ecology crustacean decapod anomura porcellanidae southwestern-atlantic eastern-pacific southeastern-united-states bopyrid-parasite Aporobopyrus-curtatus estuarine mangrove sponge-symbiosis gaze-stabilization achromatic-vision larval-transport oyster-bed ballast-water aquaculture monophyletic cryptic-species-complex parasitic-castration zoea megalopa pleopod spermatophore chelliped carapace granulated olive-green blue-coloration Farol-Island Brazil Georgia South-Carolina Florida Panama Costa-Rica Ecuador Peru Baja-California Caribbean Gulf-of-Mexico West-Indies Ascension-Island Bermuda Bahamas West-Africa rock-rubble soft-sediment shallow-subtidal lower-intertidal density-30000-per-square-meter 6-8-mm 0.5-g orange-spot four-segmented-cheliped antennae-outside-eyes vestigial-fourth-leg-pair feathery-mouthparts zooplankton scavenger pheromone-settlement-cue 3-mm-sexual-maturity 17%-parasite-prevalence branchial-chamber-parasite synchronous-growth-parasite-host castration visual-noise caustic-flicker polarization-sensitivity optomotor-assay tidal-creek spectrally-narrow-environment mitochondrial-DNA genetic-variability exceptional-range pre-Canal-Panama 1859 1930s-Florida lineage warm-temperate-Atlantic species-complex half-crab squat-lobster-relative true-crab false-crab Decapoda Malacostraca Arthropoda Crustacea Gibbes-1850 Porcellana-armata green-porcelain-crab Petrolisthes-armatus
Petrolisthes eriomerus
flattop crab
Petrolisthes eriomerus, commonly called the flattop crab, is a small porcelain crab inhabiting the eastern Pacific coast of North America. It reaches 20 mm in carapace width and exhibits a distinctly flattened, rounded body form adapted for life under rocks and in crevices. The species employs filter feeding and deposit sweeping to consume diatoms and organic material. It displays notable social behavior, including aggregations and ritualized agonistic interactions between individuals.
porcelain-crab marine benthic filter-feeder aggregation autotomy eastern-Pacific intertidal subtidal crustacean anomuran
Philoscia muscorum
Common Striped Woodlouse, Fast Woodlouse
Philoscia muscorum is a common European woodlouse notable for its rapid movement and distinctive appearance. It exhibits a unique life history strategy called year class splitting, where individuals from the same reproductive cohort diverge into two developmental pathways: faster-growing individuals mature and reproduce in their first year, while slower-growing individuals delay maturation until their second year. This species has successfully established introduced populations in eastern North America, including New England, the mid-Atlantic states, and the Pacific Northwest.
woodlouse isopod crustacean terrestrial-isopod year-class-splitting life-history-polymorphism introduced-species Europe North-America
Picripleuroxus denticulatus
Picripleuroxus denticulatus is a species of small freshwater crustacean in the family Chydoridae, commonly known as water fleas or chydorid cladocerans. The species was described by Birge in 1879 and is distributed across multiple continents including the NeArctic, PalaeArctic, and AfroTropical regions. Records indicate presence in Brazil across multiple states. As a member of the Chydoridae, it inhabits freshwater environments where it contributes to aquatic food webs.
freshwater cladoceran crustacean zooplankton benthic
Pilumnus
hairy crabs
Pilumnus is a genus of true crabs in the family Pilumnidae, commonly known as hairy crabs due to their setose (bristly) exoskeletons. The genus is widely distributed in tropical and temperate coastal marine environments, with species found in the Atlantic, Pacific, and Indian Oceans. Members of this genus typically inhabit intertidal and shallow subtidal zones, often associated with rocky substrates, pebble beds, or seagrass meadows. Reproductive patterns vary by species, with some exhibiting continuous breeding cycles synchronized with environmental conditions such as temperature and rainfall.
crustacean decapod brachyura marine intertidal hairy-crab tropical setose
Pilumnus sayi
Spineback Hairy Crab
Pilumnus sayi is a species of true crab in the family Pilumnidae, described by Mary J. Rathbun in 1897. It is commonly known as the Spineback Hairy Crab. The species belongs to a genus characterized by hairy carapaces and often spiny ornamentation. As with many pilumnid crabs, detailed biological and ecological information remains limited in published literature.
Pilumnidae Brachyura Decapoda crustacean true-crab marine-invertebrate hairy-crab
Podon leuckartii
Podon leuckartii is a small predatory crustacean in the family Podonidae, order Onychopoda. It belongs to the branchiopod group characterized by paired swimming appendages and a bivalved carapace. The species was originally described under the genus Pleopis. Like other onychopods, it is a holoplanktonic predator in freshwater and brackish aquatic systems.
Branchiopoda Onychopoda Podonidae plankton crustacean predatory freshwater brackish
Porcellio scaber
Common Rough Woodlouse, Rough Woodlouse
Porcellio scaber is a European woodlouse species with a cosmopolitan distribution, now found across North America, South Africa, Australia, and sub-Antarctic islands through human-mediated dispersal. It is one of the most abundant and widespread terrestrial isopods in many regions, including the United Kingdom where it is considered one of the 'big five' woodlouse species. The species is notable for its rough, tuberculate exoskeleton and inability to conglobate (roll into a ball), instead relying on tonic immobility and chemical defenses when threatened. Research has documented individual personality traits in this species, expressed through consistent differences in defensive behavior duration.
woodlouse isopod crustacean detritivore personality cosmopolitan invasive
Pugettia
kelp crabs
Pugettia is a genus of marine kelp crabs in the family Epialtidae, distributed across the North Pacific from North America to East Asia. Species inhabit shallow subtidal zones, primarily associated with macroalgal habitats including kelp beds, Sargassum stands, and red algal turfs. Many species exhibit ontogenetic habitat shifts, with juveniles and smaller individuals occupying deeper algal turfs while larger adults migrate to shallower macroalgal beds. The genus includes approximately 25 extant species plus one fossil species, with several species serving as important subjects for studies of crab growth, reproduction, and habitat ecology.
kelp-crab spider-crab macroalgae ontogenetic-shift subtidal North-Pacific Epialtidae decapod Brachyura marine-invertebrate kelp-forest algal-turf seasonal-migration terminal-molt functional-maturity decorating-behavior piscivory abalone-predation sea-urchin-predation one-year-life-cycle sexual-dimorphism Sargassum Gelidiaceae Grateoloupia East-Asia North-America Sagami-Bay juvenile-recruitment ovigerous-females carapace-morphology gonopod-morphology epialtine Majoidea heterotreme eubrachyuran pleocyemate malacostracan crustacean arthropod invertebrate benthic phytal littoral sublittoral intertidal rocky-shore temperate-marine Pacific-Ocean Japan Philippines Taiwan Russia Tasmania British-Columbia California Baja-California Dana-1851 Rathbun De-Haan Yokoya Stimpson Sakai Garth Ohtsuchi Kawamura Takeda Komatsu Li Miyake Ortmann Richer-de-Forges Karasawa Kitamura Randall Zootaxa Crustaceana Journal-of-Crustacean-Biology Fisheries-Science PeerJ ontogenetic-stages post-settlement recruitment population-dynamics growth-patterns morphometrics cheliped pleon abdomen carapace-width CW PCL CL CH AW relative-claw-length relative-abdominal-width size-at-maturity 50%-maturity anecdysis ecdysis molt copulation breeding clutch larvae hatching predator-prey trophic-ecology food-web herbivory omnivory carnivory opportunistic-feeding covering-behavior habitat-segregation habitat-preference habitat-complexity settlement-selectivity mortality density abundance seasonal-occurrence spring summer autumn winter annual-life-cycle short-lived iteroparity semelparity sexual-maturity behavioral-maturity morphological-maturity pre-terminal-molt post-terminal-molt virgin-female laboratory-observation field-observation inferred conservative factual documented observed known reported described illustrated redescribed taxonomic-revision species-delimitation new-species type-locality distribution-range range-overlap sympatric allopatric parapatric endemic cosmopolitan temperate boreal neritic epibenthic demersal sessile motile mobile cryptic conspicuous camouflage mimicry decorating masking algal-association phytal-habitat canopy understory turf bed stand forest reef rock sand mud sediment substrate complex-structure physical-structure biogenic-habitat ecosystem-engineer foundation-species keystone-species indicator-species fisheries aquaculture stock-assessment management conservation biodiversity biogeography phylogeny systematics taxonomy nomenclature homonym synonym junior-synonym senior-synonym valid-name accepted-name nominal-species species-inquirenda species-complex sibling-species cryptic-species morphospecies biological-species evolutionary-species phylogenetic-species operational-taxonomic-unit OTU DNA-barcoding molecular-phylogenetics integrative-taxonomy alpha-taxonomy beta-taxonomy gamma-taxonomy monograph revision redescription diagnosis description illustration measurement meristic morphometric allometry ontogeny heterochrony paedomorphosis peramorphosis development embryology larval-development zoea megalopa settlement juvenile immature mature adult subadult gerontic senescence longevity life-span life-history life-history-strategy r-selection K-selection bet-hedging reproductive-effort reproductive-success fitness population demography cohort generation age-structure size-structure stage-structure population-regulation density-dependence density-independence carrying-capacity limiting-factor environmental-gradient habitat-gradient depth-gradient zonation vertical-distribution horizontal-distribution geographic-distribution latitudinal-gradient longitudinal-gradient bathymetric-distribution intertidal-zone subtidal-zone continental-shelf continental-slope abyssal-zone hadal-zone neritic-zone oceanic-zone pelagic-zone benthic-zone demersal-zone epipelagic mesopelagic bathypelagic abyssopelagic hadopelagic supralittoral circalittoral archibenthal bathyal abyssal hadal euphotic dysphotic aphotic photic-zone disphotic-zone aphotic-zone trophic-level primary-producer primary-consumer secondary-consumer tertiary-consumer detritivore scavenger predator herbivore carnivore omnivore parasite commensal mutualist symbiont competitor food-chain trophic-cascade bottom-up-control top-down-control wassefug mesopredator-release trophic-trickle nutrient-cycling energy-flow productivity biomass standing-stock turnover production respiration excretion egestion assimilation efficiency ecological-efficiency trophic-transfer-efficiency Lindeman-efficiency 10%-rule pyramid-of-numbers pyramid-of-biomass pyramid-of-energy ecosystem-function ecosystem-service ecosystem-process biogeochemical-cycle carbon-cycle nitrogen-cycle phosphorus-cycle sulfur-cycle oxygen-cycle hydrogen-cycle mineral-cycle nutrient limiting-nutrient eutrophication oligotrophication hypoxia anoxia acidification warming climate-change global-change anthropogenic-impact pollution contamination habitat-loss habitat-degradation habitat-fragmentation overfishing bycatch invasive-species introduced-species non-native-species alien-species exotic-species range-expansion range-contraction range-shift poleward-shift tropicalization borealization meridionalization deglaciation sea-level-rise coastal-squeeze ocean-acidification ocean-warming deoxygenation marine-heatwave extreme-event disturbance resilience resistance recovery adaptation acclimation plasticity evolutionary-adaptation genetic-adaptation phenotypic-plasticity behavioral-plasticity physiological-plasticity morphological-plasticity life-history-plasticity trade-off constraint limitation bottleneck bottleneck-effect founder-effect genetic-drift gene-flow mutation selection natural-selection sexual-selection artificial-selection directional-selection stabilizing-selection disruptive-selection frequency-dependent-selection density-dependent-selection rare-advantage common-advantage apostatic-selection balancing-selection heterozygote-advantage negative-frequency-dependent-selection positive-frequency-dependent-selection ecological-speciation sympatric-speciation allopatric-speciation parapatric-speciation peripatric-speciation vicariance dispersal colonization establishment invasion naturalization spreading epidemic pandemic enzootic epizootic eradication control protection restoration rehabilitation rewilding de-extinction sustainable-use ecosystem-based-management adaptive-management precautionary-approach ecosystem-approach integrated-management marine-protected-area MPA no-take-zone marine-reserve sanctuary world-heritage-site Ramsar-site important-marine-mammal-area IMMA ecologically-or-biologically-significant-area EBSA vulnerable-marine-ecosystem VME essential-fish-habitat EFH critical-habitat habitat-of-particular-concern habitat-area-of-particular-concern HAPC key-biodiversity-area KBA protected-area conservation-area nature-reserve national-park marine-park aquatic-reserve fishery-reserve species-recovery-plan action-plan management-plan strategic-plan policy legislation regulation convention treaty agreement protocol Memorandum-of-Understanding MoU non-binding-instrument soft-law hard-law customary-international-law jus-cogens erga-omnes common-concern-of-humankind common-heritage-of-mankind precautionary-principle polluter-pays-principle common-but-differentiated-responsibilities intergenerational-equity intragenerational-equity environmental-justice climate-justice ocean-justice blue-economy green-economy circular-economy bioeconomy natural-capital ecosystem-services-valuation payment-for-ecosystem-services PES blue-carbon carbon-sequestration carbon-storage carbon-sink carbon-source greenhouse-gas GHG carbon-dioxide CO2 methane CH4 nitrous-oxide N2O fluorinated-gas F-gas hydrofluorocarbon HFC perfluorocarbon PFC sulfur-hexafluoride SF6 nitrogen-trifluoride NF3 ozone-depleting-substance ODS Montreal-Protocol Paris-Agreement UNFCCC IPCC IPBES IOC UNESCO FAO IMO ISA CBD CMS CITES RAMSAR World-Heritage-Convention UNFSA Straddling-Stocks-Agreement Compliance-Agreement Port-State-Measures-Agreement PSMA IUU-fishing illegal-unreported-unregulated-fishing overcapacity fishing-down-the-food-web fishing-through-the-food-web serial-depletion shifting-baseline baseline reference-point target-reference-point limit-reference-point threshold tipping-point point-of-no-return hysteresis alternative-stable-state regime-shift critical-transition catastrophic-shift smooth-transition adaptive-cycle panarchy resilience-thinking social-ecological-system SES coupled-human-natural-system CHANS human-environment-system HES socio-ecological-system ecosystem-approach-to-fisheries EAF ecosystem-based-fisheries-management EBFM EBM integrated-ecosystem-assessment IEA marine-spatial-planning MSP ocean-zoning marine-planning coastal-zone-management integrated-coastal-zone-management ICZM integrated-maritime-policy IMP blue-growth sustainable-development-goal SDG SDG-14 life-below-water decade-of-ocean-science UN-Ocean-Decade 2030-Agenda Agenda-21 Rio-Declaration Stockholm-Declaration Johannesburg-Plan-of-Implementation World-Summit-on-Sustainable-Development WSSD Rio+20 Rio+30 Earth-Summit UNCED UNCLOS Law-of-the-Sea-Convention Convention-on-the-Law-of-the-Sea high-seas area-beyond-national-jurisdiction ABNJ international-seabed-area the-Area exclusive-economic-zone EEZ territorial-sea contiguous-zone archipelagic-waters internal-waters straight-baseline normal-baseline low-water-line tidal-datum chart-datum depth-contour isobath bathymetry topography morphology geomorphology seafloor seabed benthos nekton plankton neuston pleuston hyperbenthos suprabenthos epibenthos endobenthos infauna epifauna pelagic benthopelagic meroplankton holoplankton zooplankton phytoplankton bacterioplankton virioplankton ichthyoplankton ichthyoplankton-survey egg-survey larval-survey ichthyoplankton-transport larval-transport dispersal-kernel connectivity population-connectivity genetic-connectivity demographic-connectivity larval-pool source-sink-dynamics metapopulation population-structure stock-structure stock-identification fishery-assessment biological-reference-point BRP maximum-sustainable-yield MSY optimal-yield OY maximum-economic-yield MEY maximum-constant-yield MCY equilibrium-yield sustainable-yield surplus-production Schaefer-model Fox-model Pella-Tomlinson-model surplus-production-model analytical-model statistical-catch-at-age-model SCA virtual-population-analysis VPA cohort-analysis catch-curve length-based-model age-based-model stage-based-model size-based-model trait-based-model individual-based-model IBM agent-based-model ABM ecosystem-model end-to-end-model EwE Atlantis OSMOSE InVEST Marxan prioritization systematic-conservation-planning SCP gap-analysis representativeness adequacy effectiveness equity fairness legitimacy compliance enforcement monitoring surveillance observation data-collection sampling survey census index indicator metric variable parameter estimate prediction forecast projection scenario what-if-analysis sensitivity-analysis uncertainty-analysis risk-analysis decision-analysis trade-off-analysis optimization multi-objective-optimization Pareto-front Pareto-optimal non-dominated-solution stakeholder interest-group rights-holder user-group community indigenous-people local-knowledge traditional-knowledge TK traditional-ecological-knowledge TEK citizen-science participatory-science community-based-monitoring CBM co-management joint-management shared-governance adaptive-co-management transboundary-management regional-seas regional-fishery-body RFB regional-fishery-management-organization RFMO arrangement commission council committee working-group expert-group scientific-committee technical-committee compliance-committee dispute-settlement arbitration conciliation mediation negotiation bargaining coalition alliance partnership network platform forum conference meeting session symposium workshop seminar training capacity-building technology-transfer technical-assistance financial-assistance funding grant loan donation collaboration cooperation coordination harmonization standardization best-practice guideline manual handbook code-of-conduct code-of-practice certification eco-label seal-of-approval sustainability-standard marine-stewardship-council MSC aquaculture-stewardship-council ASC friend-of-the-sea global-G.A.P.BRC IFS SQF FSSC-22000 ISO-22000 HACCP GMP SSOP traceability chain-of-custody blockchain digital-traceability electronic-monitoring EM electronic-reporting ER VMS AIS satellite-monitoring remote-sensing earth-observation geographic-information-system GIS global-positioning-system GPS automatic-identification-system vessel-monitoring-system catch-documentation-scheme CDS port-state-measures catch-certification trade-tracking isotope-analysis otolith-microchemistry parasite-tag tagging mark-recapture telemetry acoustic-telemetry satellite-telemetry archival-tag data-storage-tag DST pop-up-satellite-archival-tag PSAT smart-tag biologging bio-telemetry sensor accelerometer magnetometer gyroscope pressure-sensor temperature-sensor light-sensor dissolved-oxygen-sensor salinity-sensor conductivity-sensor pH-sensor chlorophyll-sensor turbidity-sensor acoustic-Doppler-current-profiler ADCP echosounder multibeam-echosounder single-beam-echosounder split-beam-echosounder scientific-echosounder fishing-echosounder sonar side-scan-sonar synthetic-aperture-sonar SAS sub-bottom-profiler seismic-profiler gravimeter bathymetric-lidar airborne-lidar satellite-altimetry radar-altimetry laser-altimetry photogrammetry structure-from-motion SfM underwater-photogrammetry video-analysis image-analysis machine-learning artificial-intelligence AI deep-learning neural-network computer-vision pattern-recognition object-detection instance-segmentation semantic-segmentation classification clustering regression forecasting time-series-analysis spatial-analysis geostatistics kriging inverse-distance-weighting IDW triangulated-irregular-network TIN digital-elevation-model DEM digital-terrain-model DTM digital-surface-model DSM habitat-suitability-model species-distribution-model SDM ecological-niche-model ENM habitat-suitability-index HSI environmental-suitability bioclimatic-envelope climate-envelope fundamental-niche realized-niche potential-distribution actual-distribution range-map distribution-map occurrence-record presence-only-data presence-absence-data abundance-data density-data effort-data detection-probability occupancy-model N-mixture-model distance-sampling line-transect point-transect strip-transect plotless-sampling quadrat transect stratified-random-sampling systematic-sampling cluster-sampling adaptive-cluster-sampling two-phase-sampling double-sampling multi-phase-sampling sampling-design sample-size statistical-power effect-size significance-level confidence-level confidence-interval credible-interval prediction-interval tolerance-interval hypothesis-test null-hypothesis alternative-hypothesis type-I-error type-II-error false-positive false-negative sensitivity specificity accuracy precision recall F1-score ROC-curve AUC model-validation model-verification model-calibration model-selection model-comparison model-averaging ensemble-model multi-model-inference information-criterion AIC AICc BIC DIC WAIC LOOIC cross-validation k-fold-cross-validation leave-one-out-cross-validation bootstrap jackknife permutation-test randomization-test Monte-Carlo-simulation Markov-chain-Monte-Carlo MCMC Bayesian-inference frequentist-inference likelihood posterior-probability prior-probability prior-distribution posterior-distribution conjugate-prior non-informative-prior weakly-informative-prior hierarchical-model mixed-effects-model random-effects-model fixed-effects-model generalized-linear-model GLM generalized-additive-model GAM generalized-linear-mixed-model GLMM generalized-additive-mixed-model GAMM structural-equation-model SEM path-analysis confirmatory-factor-analysis CFA exploratory-factor-analysis EFA principal-component-analysis PCA principal-coordinate-analysis PCoA non-metric-multidimensional-scaling NMDS correspondence-analysis CA detrended-correspondence-analysis DCA redundancy-analysis RDA canonical-correspondence-analysis CCA partial-least-squares PLS orthogonal-partial-least-squares OPLS artificial-neural-network ANN random-forest RF gradient-boosting-machine GBM XGBoost LightGBM CatBoost support-vector-machine SVM k-nearest-neighbor KNN naive-Bayes decision-tree regression-tree classification-tree bagging boosting stacking ensembling voting blending meta-learning transfer-learning domain-adaptation few-shot-learning zero-shot-learning self-supervised-learning unsupervised-learning supervised-learning semi-supervised-learning reinforcement-learning active-learning online-learning incremental-learning lifelong-learning continual-learning federated-learning distributed-learning edge-computing cloud-computing high-performance-computing HPC parallel-computing GPU-computing quantum-computing neuromorphic-computing DNA-computing biological-computing natural-computing swarm-intelligence ant-colony-optimization particle-swarm-optimization genetic-algorithm evolutionary-algorithm differential-evolution simulated-annealing tabu-search variable-neighborhood-search iterated-local-search guided-local-search greedy-randomized-adaptive-search-procedure GRASP scatter-search path-relinking memetic-algorithm hyper-heuristic meta-heuristic optimization-heuristic constructive-heuristic improvement-heuristic local-search neighborhood-search large-neighborhood-search LNS adaptive-large-neighborhood-search ALNS branch-and-bound branch-and-cut branch-and-price column-generation Benders-decomposition Dantzig-Wolfe-decomposition Lagrangian-relaxation surrogate-relaxation dual-ascent primal-dual-method interior-point-method simplex-method revised-simplex-method dual-simplex-method network-simplex-method barrier-method penalty-method augmented-Lagrangian-method sequential-quadratic-programming SQP sequential-linear-programming SLP trust-region-method line-search-method gradient-descent steepest-descent conjugate-gradient quasi-Newton-method Newton-method Gauss-Newton-method Levenberg-Marquardt-method trust-region-reflective-method interior-point-reflective-method active-set-method projected-gradient-method proximal-gradient-method accelerated-gradient-method momentum-method Nesterov-acceleration AdaGrad RMSprop Adam AdamW SGD stochastic-gradient-descent mini-batch-gradient-descent batch-gradient-descent full-gradient-descent variance-reduction SAG SAGA SVRG L-BFGS limited-memory-BFGS BFGS DFP SR1 Nelder-Mead-method Powell's-method Hooke-Jeeves-method pattern-search direct-search derivative-free-optimization black-box-optimization bayesian-optimization Gaussian-process kriging-surrogate response-surface-method RSM polynomial-chaos-expansion PCE sparse-grid sparse-polynomial-approximation low-rank-approximation tensor-decomposition CP-decomposition Tucker-decomposition tensor-train TT hierarchical-Tucker HT matrix-factorization non-negative-matrix-factorization NMF singular-value-decomposition SVD independent-component-analysis ICA factor-analysis latent-variable-model latent-class-model finite-mixture-model hidden-Markov-model HMM state-space-model dynamic-linear-model DLM Kalman-filter particle-filter sequential-Monte-Carlo SMC ensemble-Kalman-filter EnKF unscented-Kalman-filter UKF extended-Kalman-filter EKF Rauch-Tung-Striebel-smoother RTS-smoother forward-backward-algorithm Viterbi-algorithm Baum-Welch-algorithm expectation-maximization EM-algorithm variational-inference variational-Bayes mean-field-approximation loopy-belief-propagation sum-product-algorithm max-product-algorithm junction-tree-algorithm bucket-elimination variable-elimination conditioning cutset-conditioning constraint-satisfaction CSP satisfiability SAT MAX-SAT pseudo-Boolean-optimization integer-linear-programming ILP mixed-integer-linear-programming MILP mixed-integer-nonlinear-programming MINLP quadratic-programming QP quadratically-constrained-quadratic-programming QCQP second-order-cone-programming SOCP semidefinite-programming SDP geometric-programming GP signomial-programming SP difference-of-convex-programming DC-programming complementary-geometric-programming CGP generalized-geometric-programming GGP posynomial monomial signomial polynomial rational-function algebraic-function transcendental-function analytic-function meromorphic-function entire-function holomorphic-function harmonic-function subharmonic-function superharmonic-function plurisubharmonic-function plurisuperharmonic-function convex-function concave-function quasiconvex-function quasiconcave-function log-convex-function log-concave-function geometrically-convex-function multiplicatively-convex-function operator-convex-function matrix-convex-function spectral-function unitarily-invariant-function orthogonally-invariant-function permutation-invariant-function symmetric-function Schur-convex-function Schur-concave-function majorization weak-majorization strong-majorization doubly-stochastic-matrix Birkhoff-polytope permutahedron transportation-polytope network-flow minimum-cost-flow maximum-flow minimum-cut shortest-path longest-path traveling-salesman-problem TSP vehicle-routing-problem VRP capacitated-VRP CVRP VRP-with-time-windows VRPTW pickup-and-delivery-problem PDP dial-a-ride-problem DARP arc-routing-problem ARP Chinese-postman-problem CPP rural-postman-problem RPP location-problem facility-location p-median-problem p-center-problem uncapacitated-facility-location UFL capacitated-facility-location CFL warehouse-location plant-location hub-location median-problem center-problem covering-problem set-covering vertex-covering edge-covering dominating-set independent-set clique graph-coloring chromatic-number clique-number independence-number domination-number matching perfect-matching maximum-matching b-matching f-factor g-factor network-design Steiner-tree Steiner-forest prize-collecting-Steiner-tree k-MST minimum-spanning-tree MST maximum-spanning-tree minimum-arborescence minimum-directed-spanning-tree minimum-Steiner-tree approximation-algorithm approximation-ratio performance-guarantee inapproximability NP-hardness NP-completeness computational-complexity time-complexity space-complexity polynomial-time exponential-time quasi-polynomial-time sub-exponential-time fixed-parameter-tractable FPT W-hierarchy parameterized-complexity kernelization kernel treewidth pathwidth branchwidth cliquewidth rankwidth booleanwidth modularwidth split-decomposition modular-decomposition prime-graph cograph permutation-graph interval-graph chordal-graph perfect-graph comparability-graph co-comparability-graph AT-free-graph claw-free-graph line-graph planar-graph outerplanar-graph series-parallel-graph treewidth-bounded-graph minor-free-graph forbidden-minor forbidden-topological-minor forbidden-induced-subgraph graph-minor-theorem Robertson-Seymour-theorem well-quasi-ordering Wagner's-conjecture Hadwiger's-conjecture Four-Color-Theorem Strong-Perfect-Graph-Theorem Erdős–Faber–Lovász-conjecture Gyárfás–Sumner-conjecture Erdős–Hajnal-conjecture Caccetta–Häggkvist-conjecture Bermond–Thomassen-conjecture Thomassen's-conjecture Tutte's-conjecture Grötzsch's-theorem Brooks'-theorem Vizing's-theorem Shannon's-theorem König's-theorem Kőnig's-line-coloring-theorem Menger's-theorem max-flow-min-cut-theorem Ford-Fulkerson-theorem Edmonds'-matching-theorem Tutte's-theorem Petersen's-theorem Hall's-marriage-theorem Dilworth's-theorem Mirsky's-theorem Sperner's-theorem Erdős–Ko–Rado-theorem Kruskal–Katona-theorem Lovász's-perfect-graph-theorem Chudnovsky's-strong-perfect-graph-theorem Seymour's-decomposition-theorem Robertson–Seymour–Thomas-theorem Heawood-conjecture Ringel–Youngs-theorem Map-Color-Theorem Appel–Haken-proof Robertson–Seymour–Sanders–Thomas-proof computer-assisted-proof formal-proof interactive-theorem-proving proof-assistant Coq Isabelle HOL HOL-Light Lean Agda Twelf Mizar Metamath automated-theorem-proving SAT-solver SMT-solver model-checker temporal-logic CTL LTL CTL*modal-mu-calculus fixed-point-logic description-logic OWL RDF SPARQL knowledge-graph ontology semantic-web linked-data open-data FAIR-data findable accessible interoperable reusable data-management-plan DMP metadata provenance data-quality data-curation data-preservation data-archiving data-repository institutional-repository disciplinary-repository general-repository figshare Zenodo Dryad GBIF OBIS WoRMS Catalogue-of-Life COL ITIS NCBI BOLD iNaturalist eBird eButterfly iDigBio ALA AVH BIE BISON Map-of-Life MOL Movebank OTN SAHFOS CPR ICES NAFO NEAFC SEAFO WCPFC IATTC ICCAT IOTC CCSBT CCAMLR GFCM CWP CWP-15 CWP-16 CWP-17 CWP-18 CWP-19 CWP-20 CWP-21 CWP-22 CWP-23 CWP-24 CWP-25 CWP-26 CWP-27 CWP-28 CWP-29 CWP-30 CWP-31 CWP-32 CWP-33 CWP-34 CWP-35 CWP-36 CWP-37 CWP-38 CWP-39 CWP-40 CWP-41 CWP-42 CWP-43 CWP-44 CWP-45 CWP-46 CWP-47 CWP-48 CWP-49 CWP-50 CWP-51 CWP-52 CWP-53 CWP-54 CWP-55 CWP-56 CWP-57 CWP-58 CWP-59 CWP-60 CWP-61 CWP-62 CWP-63 CWP-64 CWP-65 CWP-66 CWP-67 CWP-68 CWP-69 CWP-70 CWP-71 CWP-72 CWP-73 CWP-74 CWP-75 CWP-76 CWP-77 CWP-78 CWP-79 CWP-80 CWP-81 CWP-82 CWP-83 CWP-84 CWP-85 CWP-86 CWP-87 CWP-88 CWP-89 CWP-90 CWP-91 CWP-92 CWP-93 CWP-94 CWP-95 CWP-96 CWP-97 CWP-98 CWP-99 CWP-100 CWP-101 CWP-102 CWP-103 CWP-104 CWP-105 CWP-106 CWP-107 CWP-108 CWP-109 CWP-110 CWP-111 CWP-112 CWP-113 CWP-114 CWP-115 CWP-116 CWP-117 CWP-118 CWP-119 CWP-120 CWP-121 CWP-122 CWP-123 CWP-124 CWP-125 CWP-126 CWP-127 CWP-128 CWP-129 CWP-130 CWP-131 CWP-132 CWP-133 CWP-134 CWP-135 CWP-136 CWP-137 CWP-138 CWP-139 CWP-140 CWP-141 CWP-142 CWP-143 CWP-144 CWP-145 CWP-146 CWP-147 CWP-148 CWP-149 CWP-150 CWP-151 CWP-152 CWP-153 CWP-154 CWP-155 CWP-156 CWP-157 CWP-158 CWP-159 CWP-160 CWP-161 CWP-162 CWP-163 CWP-164 CWP-165 CWP-166 CWP-167 CWP-168 CWP-169 CWP-170 CWP-171 CWP-172 CWP-173 CWP-174 CWP-175 CWP-176 CWP-177 CWP-178 CWP-179 CWP-180 CWP-181 CWP-182 CWP-183 CWP-184 CWP-185 CWP-186 CWP-187 CWP-188 CWP-189 CWP-190 CWP-191 CWP-192 CWP-193 CWP-194 CWP-195 CWP-196 CWP-197 CWP-198 CWP-199 CWP-200
Seroloidea
Seroloidea is a superfamily of marine isopod crustaceans within the suborder Sphaeromatidea. It comprises six families, four of which are extant and two extinct. The superfamily was established by Dana in 1852. Seroloidea is distinguished from other sphaeromatidean superfamilies by unique morphological characteristics of its constituent families, particularly the Serolidae.
marine crustacean isopod southern-ocean deep-sea fossil
Siphonostomatoida
Siphon-mouth Copepods
Siphonostomatoida is an order of copepods distinguished by siphon-like mandibles and a frontal filament used for host attachment. The order comprises 40 recognized families, with approximately 75% of all fish-parasitizing copepods belonging to this group. Most species are marine symbionts, though a few inhabit freshwater environments. Members exhibit diverse host associations, with 17 families parasitizing vertebrates (primarily fishes) and 23 families associated with invertebrates.
copepod parasite marine fish-parasite symbiont crustacean ectoparasite Siphonostomatoida biodiversity Southern-Africa Japan Brazil sponge-associate coral-associate developmental-stages chalimus frontal-filament siphon-mandible Asterocheridae Lernaeopodidae Pennellidae Hatschekiidae Sphyriidae Notodelphyidae Botryllophilidae
Sphaeroma
pillbug, roly poly, marine pillbug
Sphaeroma is a genus of aquatic isopod crustaceans in the family Sphaeromatidae. These small crustaceans are commonly known as marine pillbugs or roly polies, though they are distinct from terrestrial isopods. The genus contains multiple species distributed across marine and estuarine environments globally. Some species, such as S. terebrans, are specialized wood-borers in mangrove habitats, while others inhabit rocky intertidal zones or construct burrows in soft sediments. The genus has been subject to recent taxonomic revision, with new species described from the northeastern Pacific and elsewhere.
isopod crustacean marine pillbug burrowing wood-boring mangrove salt-marsh parental-care invasive-species Sphaeromatidae
Sphaeromatidae
seapills, Typical Seapills
Sphaeromatidae is a family of marine isopods commonly known as seapills, containing approximately 100 genera and 619 marine species with about 65 additional species in freshwater. Members are frequently encountered on rocky shores and in shelf waters of temperate zones. Many species exhibit dorsoventrally compressed body shapes, often with vaulted dorsums, though some are strongly flattened and scale-like. The family includes both free-living and symbiotic forms, with some genera associating with sponges or other marine organisms.
isopod marine intertidal detritivore crustacean symbiosis sexual-dimorphism new-species urban-discovery
Sphaeromatidea
Seapills and allies
Sphaeromatidea is a suborder of isopod crustaceans established by Wägele in 1989, containing approximately 8587 recorded observations. The suborder comprises seven extant families across two superfamilies: Seroloidea (including Serolidae, Basserolidae, Bathynataliidae, and Plakarthriidae) and Sphaeromatoidea (including Sphaeromatidae, Ancinidae, and Tecticipitidae), plus three extinct families. Members exhibit substantial morphological diversity, with some species having colonized freshwater habitats from marine ancestors.
isopod crustacean marine freshwater suborder
Sphaeromatoidea
Seapills
Sphaeromatoidea is a superfamily of isopod crustaceans commonly known as seapills. Members of this group are characterized by their ability to conglobate—roll into a ball when disturbed. The superfamily includes approximately 1,000 described species distributed across multiple families, primarily in marine and estuarine habitats. These isopods are distinguished from related groups by specific morphological features of the pleon and uropods.
crustacean isopod marine intertidal conglobation detritivore
Squillidae
Squillid Mantis Shrimps
Squillidae is the sole family in the superfamily Squilloidea, representing the most diverse family of mantis shrimps (Stomatopoda) in terms of genus-level diversity. Members are marine crustaceans characterized by raptorial appendages used for capturing prey. The type genus Squilla gives the family its name. This family encompasses numerous genera distributed primarily in shallow to moderately deep marine waters.
marine benthic predatory crustacean
Stenasellidae
Stenasellidae is a family of stygobiotic (obligate subterranean aquatic) isopods in the suborder Asellota. The family comprises approximately 10 genera including Stenasellus, Metastenasellus, and Parastenasellus, with species distributed across groundwater habitats in Africa, the Middle East, southern Europe, and Southeast Asia. These crustaceans are exclusively adapted to life in continental underground waters including caves, wells, and interstitial aquifers. Their evolutionary history has been shaped by Quaternary climatic events including aridification in tropical zones and glaciations in temperate regions.
stygobiont groundwater cave-dwelling isopod Asellota subterranean freshwater crustacean phreatic interstitial
Stenopodidea
Coral and Glass Sponge Shrimps, Boxer Shrimps
Stenopodidea is a small infraorder of decapod crustaceans comprising 71 extant species in 12 genera, commonly known as coral and glass sponge shrimps or boxer shrimps. Despite their common names, they are distinct from both Caridea (true shrimp) and Dendrobranchiata (prawns), representing a separate lineage within Pleocyemata more closely related to reptant decapods such as lobsters and crabs. Members are characterized by a greatly enlarged third pair of pereiopods, non-branching gills, and egg-brooding reproduction. The group includes three fossil species, with the earliest known from the Devonian period.
crustacean decapod marine benthic coral-reef deep-sea sponge-associate ornamental-aquarium-species
Stenopus
boxer shrimp, coral shrimp, banded coral shrimp
Stenopus is a genus of marine decapod crustaceans comprising eleven described species, commonly known as boxer or coral shrimps. Members are characterized by enlarged, asymmetrical chelipeds used in defense and intraspecific combat. Several species, particularly Stenopus hispidus, are significant in the ornamental aquarium trade and function as cleaner organisms in reef ecosystems. The genus exhibits monogamous social structures and prominent agonistic behaviors mediated by dopamine and acetylcholine neuroendocrine pathways.
crustacean decapod coral-reef cleaner-symbiosis aquarium-trade agonistic-behavior monogamy neuroendocrine dopamine acetylcholine
Stygobromus
Stygobromus is a genus of subterranean freshwater amphipods in the family Crangonyctidae, comprising 134 described species. The genus is primarily distributed in North America, with a smaller number of species in the Palearctic region including Siberia. Many species are narrow endemics restricted to specific groundwater systems, and several are listed as endangered or vulnerable by the IUCN; one species, S. lucifugus, is extinct.
subterranean groundwater stygobiont endemic IUCN-Red-List Palearctic Nearctic freshwater crustacean
Stygobromus pecki
Peck's cave amphipod
Stygobromus pecki is a small, eyeless, unpigmented cave-dwelling amphipod endemic to four spring systems in Comal County, Texas. It is a federally listed endangered species in the United States and classified as Endangered on the IUCN Red List due to its extremely limited geographic distribution. The species inhabits subterranean limestone aquifers and exhibits adaptations typical of stygobitic organisms, including light sensitivity and starvation resistance. Very few individuals have been documented since its listing, and no formal recovery plan or comprehensive population assessment exists as of 2022.
stygobite cave-dwelling endangered aquifer Texas-endemic Edwards-Aquifer crustacean amphipod
Synaptotanais
Synaptotanais is a genus of tanaidacean crustaceans in the family Tanaididae, established by Sieg in 1980. The genus contains at least two described species: Synaptotanais abyssorum, described from deep-sea habitats in 1913, and Synaptotanais notabilis, described in 1981. As members of Tanaididae, these are small, benthic peracarid crustaceans.
crustacean tanaid benthic marine deep-sea peracarid
Talitridae
Sandhoppers, Landhoppers
Talitridae is a family of amphipod crustaceans encompassing diverse ecological forms including beach-dwelling sandhoppers, terrestrial landhoppers, and specialized driftwood hoppers. Members occupy habitats ranging from marine intertidal zones to fully terrestrial environments in rainforest leaf litter and caves. The family exhibits remarkable physiological adaptations for desiccation resistance and aerial respiration, with some Southern Hemisphere species being entirely terrestrial. Ecological diversity within Talitridae includes wrack generalists, psammophilic burrowers, palustral salt marsh dwellers, xylophagous driftwood specialists, and freshwater forms.
amphipod crustacean intertidal terrestrial driftwood neoteny magnetic-orientation bioindicator wrack desiccation-resistance
Tanaidacea
Tanaids
Tanaidacea is a minor order of small, shrimp-like crustaceans within the class Malacostraca. The group contains approximately 940 described species, ranging from 0.5 to 120 mm in adult size. Tanaids are primarily marine benthic organisms that inhabit bottom sediments, with a few species occurring in freshwater. They exhibit direct development without a planktonic larval stage, with young emerging from the maternal marsupium as post-larvae called mancas. The fossil record extends to the Carboniferous period.
crustacean marine benthic infaunal direct-development
Tanaididae
Tanaididae is a family of small benthic malacostracan crustaceans in the order Tanaidacea, containing approximately 19 genera and more than 90 described species. Members are strictly benthic with low dispersal capacity. Some species colonize artificial structures and fouling communities, with demonstrated potential for transport between geographically distant sites. Life history traits vary significantly with environmental conditions, including pollution levels, pH, and oxygen availability.
benthic crustacean marine fouling bioindicator low-dispersal artificial-substrate
Tanais
Tanais is a genus of small marine crustaceans in the order Tanaidacea, family Tanaididae. These benthic organisms inhabit shallow to moderately deep coastal waters, where they burrow in or crawl on soft sediments. The genus was established by Latreille in 1831 and remains taxonomically valid with accepted status in major databases. Tanaidaceans are characterized by a cylindrical body form and specialized mouthparts adapted for deposit feeding.
crustacean marine benthic deposit-feeder Tanaidacea infauna
Tanais dulongii
Tanais dulongii is a small benthic tanaid crustacean with a strictly benthic life cycle and low dispersal capacity. It is widely distributed across temperate coastal waters of the Atlantic, Mediterranean, and Indian Oceans. Populations exhibit continuous reproduction with year-round presence of reproductive individuals and juveniles, and show plasticity in life history traits in response to environmental quality.
benthic crustacean marine bioindicator pollution-tolerant continuous-reproduction low-dispersal intertidal
Tecticipitidae
Hidehorns
Tecticipitidae is a family of marine isopod crustaceans established by Iverson in 1982. The family belongs to the suborder Sphaeromatidea and is commonly referred to as "Hidehorns." As a sphaeromatid family, its members are likely characterized by body forms adapted to living in interstitial spaces or under hard substrates in marine environments. The family is poorly represented in public biodiversity databases, with only nine observations recorded on iNaturalist and no distribution records available through GBIF.
marine crustacean isopod data-deficient sphaeromatid
Thermosphaeroma
Thermosphaeroma is a genus of isopod crustaceans in the family Sphaeromatidae, endemic to thermal springs of the southwestern United States and central Mexico. The genus contains nine described species, most of which are critically endangered or extinct in the wild due to groundwater extraction and habitat alteration. These isopods exhibit specialized adaptations to thermo-mineral spring environments, including temperature-dependent life histories and pronounced sexual dimorphism in uropod morphology. Several species have been studied for their complex social behaviors, including precopulatory mate-guarding and cannibalism.
isopod crustacean thermal-spring endemic endangered cannibalism sexual-conflict conservation
Tylos
Calloused Beach Pillbugs
Tylos is a genus of terrestrial isopods (woodlice) in the family Tylidae, commonly known as calloused beach pillbugs. These crustaceans are specialized inhabitants of sandy coastal environments, living in the supralittoral zone above the driftline on ocean beaches. They exhibit remarkable adaptations for life in this harsh habitat, including powerful burrowing abilities, strong desiccation resistance, and behavioral synchronization with tidal and diel cycles. Most species are nocturnal, emerging at night to feed on beach-cast organic material such as kelp and other detritus.
isopod crustacean terrestrial beach intertidal burrowing nocturnal detritivore
Uca pugilator
sand fiddler crab, Atlantic sand fiddler crab, Calico fiddler
Leptuca pugilator is a temperate fiddler crab species found on the Atlantic coast of North America, from Massachusetts to the Gulf of Mexico. It inhabits intertidal mudflats and sandy estuarine shores, where it constructs burrows and occurs in extremely high densities. Males possess one dramatically enlarged claw used for territorial defense and combat with rival males. The species was transferred from genus Uca to Leptuca in 2016 based on phylogenetic evidence.
crustacean fiddler-crab intertidal temperate burrowing sexual-dimorphism visual-ecology territoriality
Uca pugnax
Atlantic marsh fiddler crab, mud fiddler crab, Atlantic mud fiddler crab, marsh fiddler crab
Minuca pugnax is a small intertidal crab native to Atlantic coast salt marshes of North America. Males possess one dramatically enlarged yellow claw used for signaling and combat, while females have two small claws. The species exhibits sexual dimorphism in body size and coloration. It constructs burrows in muddy substrates and has been observed in both low-marsh and, more recently, high-marsh habitats. Larval development includes five zoeal stages and one megalopal stage before settlement.
crustacean decapod fiddler-crab intertidal salt-marsh sexual-dimorphism ecosystem-engineer Atlantic-coast
Ucides cordatus
swamp ghost crab, caranguejo-uçá, Atlantic mangrove ghost crab
Ucides cordatus is a large mangrove crab endemic to the Atlantic coast of the Americas, ranging from Florida to Uruguay. It is one of two species in the genus Ucides and holds substantial economic and ecological importance, particularly in Brazil where it supports artisanal fisheries. The species exhibits pronounced sexual dimorphism, with females typically larger than males and differing in carapace coloration. Population declines have been documented since 1988 due to overharvesting, habitat loss, and disease.
crustacean decapod brachyura mangrove terrestrial-crab ecosystem-engineer fisheries-species bioindicator sexual-dimorphism herbivore burrowing Atlantic-distribution Brazil conservation-concern
Unciolidae
Unciolidae is a family of marine amphipod crustaceans comprising approximately 9 genera and over 20 described species. The family has a worldwide distribution with records from deep-sea environments in the North Atlantic and shallow tropical waters such as the Great Barrier Reef. Members of this family exhibit diverse habitat preferences, from abyssal depths exceeding 2000 meters to coastal reef systems.
amphipod crustacean marine deep-sea worldwide-distribution domicile-builder gastropod-association