Monocorophium cylindricum
(Say, 1818)
Monocorophium cylindricum is a small amphipod crustacean in the Corophiidae, first described by Thomas Say in 1818. It belongs to a characterized by simplified mouthparts and reduced gnathopods compared to other corophiid amphipods. The inhabits marine and brackish coastal environments, where it constructs tubes from sediment and detritus. It is known from Atlantic coasts of North America.
Pronunciation
How to pronounce Monocorophium cylindricum: /ˌmɒnəʊkɔːˈroʊfiəm sɪˈlɪndrɪkəm/
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Identification
Distinguished from other Monocorophium by the cylindrical body shape referenced in its specific epithet. Differs from Corophium species by having only one (rather than two) robust setae on the margin of urosomite 1. Separated from Crassicorophium by less robust gnathopods and more slender pereiopods. The urosome and reduced mouthparts are diagnostic for the .
Appearance
Small amphipod with cylindrical, somewhat slender body form. Urosome segments are . relatively short. Pereiopods ( legs) slender, adapted for tube-dwelling rather than active swimming. Gnathopods reduced in size compared to related . small, not deeply cleft. Coloration generally pale to translucent, sometimes with faint banding.
Habitat
Marine and estuarine environments, primarily in soft sediments. Constructs permanent tubes in sand, mud, or mixed substrates, often in intertidal and shallow subtidal zones. Tolerates reduced salinity in brackish waters.
Distribution
Western Atlantic Ocean, documented from eastern coasts of North America. Records indicate presence from New England southward, though precise range boundaries require verification.
Behavior
Tube-dwelling; constructs and inhabits permanent burrows in soft sediments using silk secretions combined with sediment particles and detritus. Remains within tubes, extending and mouthparts to capture suspended particles and organic matter from passing water currents. Limited active locomotion outside tubes.
Ecological Role
Contributes to benthic structure as a tube-building infaunal organism. Its burrowing activities modify sediment properties and create heterogeneity. Serves as prey for small fish and in soft-bottom .
Similar Taxa
- Monocorophium acherusicumOverlapping distribution and ; distinguished by subtle differences in urosome setation and gnathopod proportions
- Corophium volutatorSimilar tube-dwelling habit and ; differs in having two robust urosomite setae and more robust gnathopods
- Crassicorophium bonelliiShared and superficially similar form; separated by more robust body, stronger gnathopods, and different urosome structure
More Details
Taxonomic History
Originally described by Thomas Say in 1818, this has undergone several generic reassignments. The Monocorophium was established to accommodate species with reduced gnathopods and modified urosome structure compared to the type genus Corophium. The group remains taxonomically challenging due to morphological similarity among species and limited modern revisionary work.
Research Gaps
Published ecological and behavioral studies specifically targeting M. cylindricum are sparse; much information is inferred from -level characteristics or congeneric . , reproductive , and precise requirements await dedicated study.