Xiphosura
Ancient marine arthropods unchanged for hundreds of millions of years.
Last updated
Xiphosura is an order of arthropods related to arachnids, named for its sword-like telson.[1] A semicircular carapace covers the upper part of the prosoma.[2] The body consists of two main sections: the prosoma at the front and the opisthosoma at the rear.[2]
Scientific classification
- KingdomAnimalia
- PhylumArthropoda
- SubphylumChelicerata
- OrderXiphosura
Named by Latreille, 1802
Sources: Wikipedia taxobox: Xiphosura (CC BY-SA 4.0)
Quick Facts
- Field
- Arthropod order
- Known for
- Living fossils; horseshoe crabs
- Extant species
- 4
- Adult length
- Up to 60 cm (24 in) in modern forms
- Suborder
- Xiphosurida
Facts from the source article.
Biology and range
The opisthosoma terminates in a long caudal spine called a telson.[3] Within the carapace, xiphosurans possess a maximum of four eyes.[3] On each side of the prosoma sits a compound eye, and near the front there are either one or two median ocelli.[3] Compared to other arthropods, the compound eyes exhibit a less complex structure.[3]
Pincers tip the first four leg pairs, and their inner surfaces bear spines.[4] The caudal spine possesses considerable mobility and serves to right the animal when it is flipped over.[3] A female deposits between 200 and 300 eggs into a depression, and the male subsequently fertilizes them with sperm.[3] After roughly three years of development, modern xiphosurans attain sexual maturity.[3]
What the specialist sources record
The GBIF Backbone Taxonomy lists Xiphosura Gronovius, 1764 as a genus rank synonym within class Merostomata, order Xiphosurida, family Limulidae.[5] GBIF holds 2 occurrence records for this taxon as of 15 October 2026.[5]
References
- Wikipedia, "Xiphosura" (CC BY-SA 4.0) en.wikipedia.org
- Wikipedia, "Xiphosura" (CC BY-SA 4.0), which cites: Botton, M.I. (1984) Diet and food preferences of the adult horseshoe crab Limulus polyphemus in Delaware Bay, New Jersey, USA, Marine Biology, 81, pp. 199-207; Robert D. Barnes, "Invertebrate Zoology", Holt-Saunders International, 1982, p. 590–595; Crystallographic Texture of the Arthropod Cuticle Using Synchrotron Wide Angle X-ray Diffraction; Exocuticular hyaline layer of sea scorpions and horseshoe crabs suggests cuticular fluorescence is plesiomorphic in chelicerates (we also read that source) en.wikipedia.org
- Wikipedia, "Xiphosura" (CC BY-SA 4.0), which cites: Robert D. Barnes, "Invertebrate Zoology", Holt-Saunders International, 1982, p. 590–595 (we also read that source) en.wikipedia.org
- Wikipedia, "Xiphosura" (CC BY-SA 4.0), which cites: R. C. Brusca & G. J. Brusca, "Invertebrates", Sinauer Associates, 2002; Robert D. Barnes, "Invertebrate Zoology", Holt-Saunders International, 1982, p. 590–595 (we also read that source) en.wikipedia.org
- GBIF Backbone Taxonomy and occurrence index, Xiphosura (taxon key 7098026). CC BY 4.0 (backbone); counts are facts. gbif.org
Each numbered sentence above was checked against the source it cites before publication. Sentences citing Wikipedia adapt text from the English Wikipedia article Xiphosura (contributors), used under CC BY-SA 4.0; this entry is available under the same licence. Other sources were used for facts only; no text or images are copied from them.
Also in the Codexery
More in Arachnids & Myriapods
Sources
Compiled from Wikipedia and the sources listed below. Text from Wikipedia is available under CC BY-SA 4.0; this entry is adapted from it.
- Wikipedia: Xiphosura (CC BY-SA 4.0).
- Word definitions: the , each quoted from its Wikipedia article.
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