Marine
Guides
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.
Stenopodidae
Coral Shrimps, Boxer Shrimp
Stenopodidae is a family of marine decapod crustaceans comprising approximately 6 genera and more than 30 described extant species. The family has a fossil record extending to the Devonian period. Members are commonly known as coral shrimps or boxer shrimp and are distinguished from true shrimp and prawns by morphological and phylogenetic affinities closer to reptant decapods such as lobsters and crabs. The family exhibits diverse ecological associations including fish cleaning symbioses, commensalism with deep-water corals, and obligate associations with hexactinellid sponges.
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.
Stenorhynchus seticornis
Yellowline Arrow Crab, Arrow Crab
Stenorhynchus seticornis is a marine crab commonly known as the yellowline arrow crab. It inhabits shallow subtidal zones of the western Atlantic Ocean, from North Carolina to Brazil. The species is recognized by its triangular body, elongated pointed rostrum, and long thin legs. It is nocturnal, territorial, and frequently associated with sea anemones, particularly Lebrunia danae.
Stomatopoda
Mantis Shrimps, Stomatopods
Stomatopoda is an order of marine malacostracan crustaceans comprising approximately 450 extant species. Commonly known as mantis shrimps due to their raptorial appendages resembling those of praying mantises, they represent one of the oldest crustacean lineages, having diverged from other malacostracans around 400 million years ago. The order is divided into two functional groups based on raptorial appendage morphology: "smashers" that deliver powerful blunt strikes and "spearers" that impale soft-bodied prey. Stomatopods inhabit tropical to temperate marine waters globally, with greatest diversity in tropical and subtropical regions.
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.
Taliepus nuttallii
southern kelp crab, globose kelp crab
Taliepus nuttallii, commonly known as the southern kelp crab or globose kelp crab, is a true crab species in the family Epialtidae. It inhabits kelp forest ecosystems along the East Pacific coastline. The species was originally described as Epialtus nuttallii by Randall in 1840 before being transferred to the genus Taliepus. As a member of the kelp crab group, it is adapted to life among macroalgae, though specific ecological details remain limited in available sources.
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.
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.
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.
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.
Tanytarsus
non-biting midge
Tanytarsus is a large genus of non-biting midges comprising over 480 described species. The genus belongs to the tribe Tanytarsini within the subfamily Chironominae. Larvae occur in diverse freshwater habitats, with some species inhabiting marine environments. Species-level studies reveal complex life cycles with photoperiod and temperature as key determinants of seasonal patterns.
Tarphiota fucicola
Tarphiota fucicola is a small rove beetle (Staphylinidae) in the subfamily Aleocharinae. The species is restricted to coastal marine environments in the North Pacific. It was originally described as Tachyusa fucicola by Mäklin in 1852. The specific epithet 'fucicola' refers to association with Fucus, a genus of brown algae.
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.
Telmatogeton japonicus
Telmatogeton japonicus is a marine midge species described from Japan in 1933. It has been introduced to coastal areas of North America and Europe, where it has been recorded from the Wadden Sea and Belgian marine waters. The species belongs to the subfamily Telmatogetoninae, a group of chironomid midges specialized for intertidal and marine environments.
Telmatogetoninae
Intertidal Midges
Telmatogetoninae is a subfamily of non-biting midges (Chironomidae) primarily adapted to intertidal marine and brackish water environments. The subfamily contains two genera: Telmatogeton and Thalassomya. Larvae exhibit specialized physiological adaptations for osmoregulation and desiccation resistance, enabling survival in harsh, variable saline conditions of coastal habitats. Most species inhabit rocky shores, sandy beaches, and estuarine zones, though some members occupy freshwater torrent habitats.
Thalassomya bureni
Thalassomya bureni is a species of midge in the family Chironomidae, described by Wirth in 1949. It belongs to the genus Thalassomya, a group of chironomid midges associated with marine or coastal habitats. The species is poorly documented in scientific literature, with only limited observational records available.
Thalassosmittia
Thalassosmittia is a genus of non-biting midges in the bloodworm family Chironomidae, subfamily Orthocladiinae. The genus was established by Strenzke & Remmert in 1957 and is native to Europe. Species within this genus are primarily marine shore dwellers inhabiting intertidal zones. At least one species, T. ballestai, has been described from the Tyrrhenian sub-region and functions as a biological indicator of coastal habitat quality and climate change effects.
Thambemyia
Thambemyia is a genus of long-legged flies in the family Dolichopodidae, characterized by its exclusive association with rocky intertidal habitats. The genus is distributed across the Oriental and Neotropical realms, with a single Palearctic species from Japan. Taxonomic relationships with the genus Conchopus remain unresolved, with some authors treating the latter as a synonym while others recognize it as distinct. The genus currently comprises five described species plus a new subgenus established for the Japanese species.
Thecostraca
Barnacles and Allies
Thecostraca is a class of marine crustaceans encompassing over 2,200 described species, with barnacles (subclass Cirripedia) comprising the vast majority. The group includes three major lineages: sessile suspension-feeding barnacles, parasitic ascothoracidans that infect cnidarians and echinoderms, and the enigmatic Facetotecta, known only from planktonic larvae. Members undergo distinctive larval development, typically featuring a nauplius stage followed by a cypris stage that facilitates settlement. Thecostraca exhibits remarkable life history diversity, ranging from free-living suspension feeders to endoparasites with highly derived morphologies.
Thinusa
Thinusa is a genus of small rove beetles (family Staphylinidae) inhabiting intertidal marine environments. The genus contains at least two described species: Thinusa fletcheri and T. maritima. Based on morphological characters including maxillary structure and abdominal tergite shape, Thinusa is classified in the tribe Athetini rather than Phytosini.
Thoracochaeta
Thoracochaeta is a genus of small flies in the family Sphaeroceridae, commonly known as lesser dung flies. The genus is associated with marine supralittoral habitats, particularly in coastal environments. In the Nearctic region, it has been treated as a subgenus of Leptocera (Leptocera (Thoracochaeta)), with nine species recognized. Larvae have been described for at least three species.
Thoracochaeta brachystoma
lesser dung fly
Thoracochaeta brachystoma is a small fly in the family Sphaeroceridae, commonly known as lesser dung flies. It inhabits marine supralittoral environments along sea coasts, where larvae develop in seaweed. The species occurs in both the Palearctic and Nearctic regions.
Thoracochaeta seticosta
Thoracochaeta seticosta is a species of small dung fly in the family Sphaeroceridae, originally described as Leptocera seticosta by Spuler in 1925. It belongs to the subgenus Thoracochaeta, a group associated with marine supralittoral habitats. The larvae have been formally described, distinguishing it from many related species where immature stages remain unknown. The species occurs in Europe and has been recorded in the Nearctic region.
Thoracochaeta zosterae
lesser dung fly
Thoracochaeta zosterae is a small dung fly in the family Sphaeroceridae. It inhabits coastal marine environments, where larvae develop in seaweed. The species was originally described from the Palearctic and has been recorded in the Nearctic region. It is part of a subgenus specialized for supralittoral habitats.
Trepobatinae
small waterstriders
Trepobatinae is a subfamily of small waterstriders (Gerridae) established by Matsuda in 1960. The group has undergone extensive radiation on New Guinea and surrounding archipelagos, with particularly high diversity in Melanesia. Four tribes are currently recognized: Metrobatini, Naboandelini, Stenobatini, and Trepobatini. The subfamily includes both freshwater and marine forms, with marine species concentrated in the New Guinea region.
Trophithauma rostrata
Trophithauma rostrata is a spider crab species in the family Inachidae, formerly classified under the genus Macropodia. Molecular genetic analysis (COI barcode) demonstrated that Macropodia parva should be synonymised with T. rostrata, while M. longipes was determined to be a synonym of M. tenuirostris. The species occurs in the Atlantic and Mediterranean regions. Like other inachid crabs, it exhibits epibiosis, carrying algae and other sessile organisms on its carapace.
Tylodina
Tylodina is a genus of medium-sized marine gastropods in the family Tylodinidae, order Umbraculida. Commonly known as false limpets, these sea snails have a cap-like shell resembling true limpets but are not closely related to them. The genus includes species found in the Mediterranean Sea and Eastern Atlantic Ocean, with at least four recognized species: T. perversa, T. rafinesquii, T. fungina, and T. americana. Molecular and morphological studies have clarified species boundaries within the genus, including the resurrection of T. rafinesquii as distinct from the sympatric T. perversa.
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.
Xiphosura
horseshoe crabs
Xiphosura is an order of marine chelicerate arthropods commonly known as horseshoe crabs. The group contains only four extant species, all within the family Limulidae. Xiphosurans first appeared in the fossil record approximately 480 million years ago and have retained a remarkably conserved body plan, earning them designation as living fossils. Recent phylogenomic studies have placed Xiphosura within Arachnida, often as the sister group to Ricinulei, though this classification remains under active revision. The order contains one extant suborder (Xiphosurida) and numerous extinct stem-genera.