Xiphosura
Sign in to saveXiphosura (; , in reference to its sword-like telson) is an order of arthropods related to arachnids. They are more commonly known as horseshoe crabs (a name applied more specifically to the only extant family, Limulidae). They first appear in the fossil record in the Early Ordovician, around 480 million years ago. Currently, there are only four living species. Xiphosura contains one suborder, Xiphosurida, and several stem-genera.
Species
horseshoe crabs
GENUS
- KingdomAnimalia
- PhylumArthropoda
- ClassMerostomata
- OrderXiphosurida
- FamilyLimulidae
Habitatmarine
Observations0
via GBIF
Research
1,837 papers- The ontogeny of Limulus polyphemus (Xiphosura s. str., Euchelicerata) revised: looking "under the skin".Development genes and evolution · 2018
- An "ancient" complexity? Evolutionary morphology of the circulatory system in Xiphosura.Zoology (Jena, Germany) · 2015
- Diversity and evolutionary history of RNA viruses among different horseshoe crab species.Journal of virology · 2025
- Complete mitochondrial genomes of Carcinoscorpius rotundicauda and Tachypleus tridentatus (Xiphosura, Arthropoda) and implications for chelicerate phylogenetic studies.International journal of biological sciences · 2014
- Molecular phylogeny of extant horseshoe crabs (Xiphosura, Limulidae) indicates Paleogene diversification of Asian species.Molecular phylogenetics and evolution · 2012
via PubMed
Article
11 sectionsContents
- Description
- Internal anatomy
- Reproduction
- Evolutionary history
- Classification
- Taxa removed from Xiphosura
- Cladogram
- See also
- References
- Further reading
- External links
Xiphosura (; , in reference to its sword-like telson) is an order of arthropods related to arachnids. They are more commonly known as horseshoe crabs (a name applied more specifically to the only extant family, Limulidae). They first appear in the fossil record in the Early Ordovician, around 480 million years ago. Currently, there are only four living species. Xiphosura contains one suborder, Xiphosurida, and several stem-genera.
The group has hardly changed in appearance in hundreds of millions of years; the modern horseshoe crabs look almost identical to prehistoric genera and are considered to be living fossils. The most notable difference between ancient and modern forms is that the abdominal segments in present species are fused into a single unit in adults.