Porcelain-crab
Guides
Euceramus
Euceramus is a genus of porcelain crabs (family Porcellanidae) described by Stimpson in 1860. At least one species, E. transversilineatus, has been documented as a commensal endosymbiont living within the mantle lobe of marine gastropods, specifically the Pacific crown conch Melongena patula in the Gulf of California. The genus belongs to the diverse anomuran crab radiation, characterized by a compressed body form adapted for inhabiting tight spaces.
Euceramus praelongus
Euceramus praelongus is a species of porcelain crab in the family Porcellanidae, described by Stimpson in 1860. It belongs to the infraorder Anomura, which includes hermit crabs and related groups. The species is known from limited records in the western Atlantic Ocean and Gulf of Mexico. Available information is sparse, with only nine observations documented on iNaturalist.
Pachycheles
porcelain crabs
Pachycheles is a genus of porcelain crabs (family Porcellanidae) comprising more than 40 described species. These anomuran decapods are distributed across tropical and temperate marine regions, with origins in the Indo-Pacific and subsequent spread to the Americas. The genus is characterized by fragmented lateral carapace walls and exhibits considerable morphological diversity. Several species are subject to parasitism by rhizocephalan barnacles and bopyrid isopods, which can significantly affect host growth and reproduction.
Pachycheles rudis
thickclaw porcelain crab, big-clawed porcelain crab
Pachycheles rudis is a porcelain crab in the family Porcellanidae, commonly known as the thickclaw porcelain crab or big-clawed porcelain crab. It inhabits the East Pacific coast from Baja California to Kodiak, Alaska. The species is a filter feeder that typically occurs in heterosexual pairs and exhibits size-assortative pairing with apparent long-term mate recognition. It is frequently found in crevices, nooks, and interstices, often occupying discarded barnacle shells lined with the bryozoan Alcyonidium.
Petrolisthes
porcelain crabs
Petrolisthes is a genus of marine porcelain crabs in the family Porcellanidae, containing approximately 50 extant species distributed across temperate and tropical coastal regions of the Pacific Rim and warm Western Atlantic. These small, flattened crabs occupy intertidal and subtidal zones, often forming dense aggregations under rocks and within crevices. Multiple species have been subject to intensive behavioral and ecological study, revealing complex patterns of intraspecific competition, thermal adaptation, and settlement behavior. Two species (P. cinctipes and P. manimaculis) have been sequenced, providing genomic resources for studying physiological responses to climate change.
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.
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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.
Polyonyx
Polyonyx is a genus of porcelain crabs (family Porcellanidae) comprising at least 42 described species. Most species are obligate commensals of chaetopterid polychaete worms, living inside the tubes of their hosts. The genus exhibits a transversally cylindrical body form adapted for lateral movement within worm tubes. Several species frequently cohabit host tubes with other symbionts, including larger porcellanids, pinnotherid crabs, and nudibranchs.
Polyonyx gibbesi
eastern tube crab
Polyonyx gibbesi, commonly known as the eastern tube crab, is a porcelain crab in the family Porcellanidae. It is an obligate commensal species that inhabits the tubes of polychaete worms, particularly Chaetopterus species. The species has been studied for its physiological ecology, showing lower thermal tolerance compared to some co-occurring commensal crabs. It occurs in the western Atlantic Ocean including the Gulf of Mexico and Lesser Antilles.