Streblospio benedicti | |
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Annelida |
Clade: | Pleistoannelida |
Clade: | Sedentaria |
Order: | Spionida |
Family: | Spionidae |
Genus: | Streblospio |
Species: | S. benedicti |
Binomial name | |
Streblospio benedicti Webster, 1879 | |
Streblospio benedicti (also called the Ram's horn worm) is a small polychaete native to the Western Atlantic, where its distribution ranges from the Gulf of Saint Lawrence to Venezuela. [1] [2] Sexual maturity is reached at around 9 to 14 weeks and populations and individuals may vary during development. It can be found in the mudflats and soft sediments of estuaries and coastal waters. Its general habitat includes oyster reefs, mangroves, grass beds, marinas, and docks while the tidal range where S. benedicti can be found is subtidal to intertidal. Additionally, S. benedicti can tolerate a broad range of temperatures and salinities. Due to its tolerance of high organic contents, S. benedicti is a pioneer organism of new habitats that it settles in. Furthermore, despite its small size, only reaching a maximum of 20 mm (0.79 in) in length, S. benedicti plays an important role in estuarine food webs as it can reach high population densities and is a substantial grazer of phytoplankton. [3]
Streblospio benedicti is native to the Western Atlantic ranging from the Gulf of Saint Lawrence to Venezuela, but its distribution can reach as far as Japan. Streblospio benedicti was first found in San Francisco bay where it was most abundant in the soft sediments of the bay. It was then reported to be found in Elkhorn Slough, South of San Francisco Bay, and even further South in Mexico, in the Topolobampo lagoon on the Gulf of California and the Urias estuary near Mazatlan. The distribution range of Streblospio benedicti also includes the Northeast Atlantic such as Ireland, France, and Belgium. There have also been reports of Streblospio benedicti from the Caribbean and the Mediterranean Sea, and the Black and Caspian Seas. [3] [4]
Streblospio benedicti is common in estuarine habitats. They are typically found in muddy or soft-sediment areas, such as mudflats, seagrass beds, and marshes. [5] [6] The species is also adapted to rapid colonization, due to its capacity for small-scale dispersal following larval development. S. benedicti is known to flourish in physical environments where there have been random or environmental disturbances, due to lessened competition in these areas. The Ram's Horn Worm is known as an opportunistic pioneering species for this reason, as it tends to explore newly disturbed areas. [7] [6] Much of the ability to traverse these environmentally altered areas, is due to S. benedicti's tolerance for pollution. [8] [6] The species is also generally able to tolerate a broad range of salinity. However, population levels are known to decrease with the decrease of salinity levels in their environment. [9] [6] The same is true for temperature, as the species is generally able to tolerate a large range of temperatures. Though, it is speculated that cold water temperatures can limit the occurrence of S. benedicti in some habitats during winter and spring. Streblospio benedicti is also a relatively long-lived species, as individuals tend to exhibit lifespans ranging from 30 to 75 weeks.
S. benedicti is a specialist when it comes to finding resources, and is a generalist in terms of discovering habitats. However, if resources are limited, the species has proven to be a capable competitor. [10] [6] Due to its tendency to reside in sediment surfaces, Streblospio benedicti is quite vulnerable to epibenthic predators. These include organisms such as blue crabs, grass shrimp, and flounder. [11] [6]
Streblospio benedicti is a small (6–20 mm (0.24–0.79 in) in length) polychaete. It is segmented and looks like a tube or worm. It has a cone-shaped head with four eyes, feeding palps and gills. Usually rusty, red-brown color, its gills have green bands. It's morphologically very similar to S. gynobranchiata, a closely related species. Its morphology is similar to many spionidae polychaetes (a family of marine worms). Other species that Streblospio benedicti are mistaken for include Streblospio shrubsoli and Streblospio benedicti japonica. The morphology of feeding palps and cilia were found to be shared between both Streblospio benedicti and Streblospio shrubsoli. However, they did have different morphological functions of papillae. [12] [6]
Streblospio benedicti reproduces sexually and has two separate sexes. They typically experience high rates of reproduction and high growth rates. [13] [6] Females have pouches, called dorsal brood pouches, which are used to incubate the embryos during the early stages of development. [5] [6] The species is poecilogonous, which means that the females exhibit two distinct reproductive strategies during early larval development. These strategies are genetically determined and differ in their brood development. Both forms of development can also occur within the same population. [5] [6] In planktotrophic brood development, some females will produce large amounts of small eggs, which are around 60-70 μm in diameter. These developed larvae typically have long swimming setae and will live in and feed on plankton for a period of up to seven weeks. Lecithotrophic brood development occurs when the females produce fewer amounts of large eggs, which are around 100-200 μm in diameter. In contrast to the planktotrophic offspring, the lecithotrophic larvae lack the swimming setae. They are physically capable of immediate settlement but they will typically remain in the water column for a period ranging from a couple of hours to one week. [5] [6]
Streblospio benedicti is commonly used as an indicator organism for marine nutrient pollution. [14] [6]
Benthos, also known as benthon, is the community of organisms that live on, in, or near the bottom of a sea, river, lake, or stream, also known as the benthic zone. This community lives in or near marine or freshwater sedimentary environments, from tidal pools along the foreshore, out to the continental shelf, and then down to the abyssal depths.
Bioturbation is defined as the reworking of soils and sediments by animals or plants. It includes burrowing, ingestion, and defecation of sediment grains. Bioturbating activities have a profound effect on the environment and are thought to be a primary driver of biodiversity. The formal study of bioturbation began in the 1800s by Charles Darwin experimenting in his garden. The disruption of aquatic sediments and terrestrial soils through bioturbating activities provides significant ecosystem services. These include the alteration of nutrients in aquatic sediment and overlying water, shelter to other species in the form of burrows in terrestrial and water ecosystems, and soil production on land.
A veliger is the planktonic larva of many kinds of sea snails and freshwater snails, as well as most bivalve molluscs (clams) and tusk shells.
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Capitella capitata is a polychaete worm that grows up to 10 cm in length. It is often blood-red in colour. The species is sedentary and fragile, with a flexible body.
Intertidal ecology is the study of intertidal ecosystems, where organisms live between the low and high tide lines. At low tide, the intertidal is exposed whereas at high tide, the intertidal is underwater. Intertidal ecologists therefore study the interactions between intertidal organisms and their environment, as well as between different species of intertidal organisms within a particular intertidal community. The most important environmental and species interactions may vary based on the type of intertidal community being studied, the broadest of classifications being based on substrates—rocky shore and soft bottom communities.
Thorson's rule is an ecogeographical rule which states that benthic marine invertebrates at low latitudes tend to produce large numbers of eggs developing to pelagic and widely dispersing larvae, whereas at high latitudes such organisms tend to produce fewer and larger lecithotrophic (yolk-feeding) eggs and larger offspring, often by viviparity or ovoviviparity, which are often brooded.
Eunicidae is a family of marine polychaetes. The family comprises marine annelids distributed in diverse benthic habitats across Oceania, Europe, South America, North America, Asia and Africa. The Eunicid anatomy typically consists of a pair of appendages near the mouth (mandibles) and complex sets of muscular structures on the head (maxillae) in an eversible pharynx. One of the most conspicuous of the eunicids is the giant, dark-purple, iridescent "Bobbit worm", a bristle worm found at low tide under boulders on southern Australian shores. Its robust, muscular body can be as long as 2 m. Eunicidae jaws are known from as far back as Ordovician sediments. Cultural tradition surrounds Palola worm reproductive cycles in the South Pacific Islands. Eunicidae are economically valuable as bait in both recreational and commercial fishing. Commercial bait-farming of Eunicidae can have adverse ecological impacts. Bait-farming can deplete worm and associated fauna population numbers, damage local intertidal environments and introduce alien species to local aquatic ecosystems.
Marine larval ecology is the study of the factors influencing dispersing larvae, which many marine invertebrates and fishes have. Marine animals with a larva typically release many larvae into the water column, where the larvae develop before metamorphosing into adults.
Mediaster aequalis is a species of sea star in the family Goniasteridae. It is native to the west coast of North America, ranging from Alaska to California. It is found in various habitats including beaches during very low tides, and at depths down to about 500 m (1,600 ft). Also known as the vermilion sea star, it is the type species of the genus Mediaster and was first described in 1857 by the American zoologist William Stimpson.
Thalassonerita is a monotypic genus of sea snails, marine gastropod mollusks in the family Neritidae. Its sole species is Thalassonerita naticoidea. T. naticoidea is endemic to underwater cold seeps in the northern Gulf of Mexico and in the Caribbean. Originally classified as Bathynerita, the genus was reassessed in 2019 after Thalassonerita was found to be a senior synonym of Bathynerita.
Capitella teleta is a small, cosmopolitan, segmented annelid worm. It is a well-studied invertebrate, which has been cultured for use in laboratories for over 30 years. C. teleta is the first marine polychaete to have its genome sequenced.
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Ficopomatus enigmaticus, commonly known as the Australian tubeworm, is a species of serpulid tubeworms. Their true native range is unknown, but they probably originated in the Southern Hemisphere, perhaps from the Indian Ocean and the coastal waters of Australia. Today they have a cosmopolitan distribution, having been introduced to shallow waters worldwide. The Australian tubeworm is an invasive species that dominates and alters habitats, reduces water quality, depletes resources, and causes biofouling.
The term poecilogony was coined by Alfred Mathieu Giard to describe a polymorphism in larval development in marine invertebrates. To date, this life history trait is only known in a small number of polychaete taxa, as well as some sacoglossan mollusks. In some cases, the variation in larval type is a 'plastic' trait in that it is environmentally mediated. In other cases, the larval type is genetically determined - a good example is the polychaete Streblospio benedicti, where some mothers release small planktotrophic eggs and other mothers release large lecithotrophic eggs. In either case, the variation in larval type generally involves the production of larvae that differ in feeding mode and/or developmental time.
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Judith Grassle is a Professor Emeritus in the Department of Marine and Coastal Sciences at Rutgers University. Grassle is a benthic ecologist known for research on invertebrates, especially polychaete worms including the now-named Capitella teleta. Grassle became a Fellow of the American Association for the Advancement of Science in 1993.
Maldanidae is a family of more than 200 species of marine polychaetes commonly known as bamboo worms or maldanid worms. They belong to the order Capitellida, in the phylum Annelida. They are most closely related to family Arenicolidae, and together form the clade Maldanomorpha.
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Media related to Streblospio benedicti at Wikimedia Commons