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Fossil horseshoe crabs

Created 1 May 1997; Modified 14 February 2001

This page details the critters which I spent about four years studying formally at the University of Manchester, and what seems now to be an ongoing concern! If after reading through this information, you feel that you have something to add, or something to criticise, I'd like to hear from you.

List of Contents


Horseshoe crabs have been around in one disguise or another for quite some time now, let's just say since the Lower Silurian for arguments sake. Personally, I reckon they'll outlive that troublesome species Homo sapiens hands (or at least pincered feet) down. Why? Well, because they are good at what they do and they don't seem to have any intention of changing their mode of life or gross body morphology. This is why they are often refered to as 'Living fossils'.

H.C. Links

Yes, there are actually a few other links to these beasties. Here's some for the meantime. I'll arrange them a little better into subject headings when I get time. If you know of any links which contain, explain or even have a vague whiff of Horseshoe crab about them, please e-mail me with the details.

  • Invertebrate species of the VCR-LTER
  • Noah's Boat Supply Order Form
  • Horseshoe Crab Facts and Figures
  • Alternatives Page
  • Horseshoe crab facts
  • LAL information
  • Maryland DNR Fish Fun Facts
  • Harvesting of Horseshoe crabs
  • The Horseshoe crab or King crab
  • Population Surveys
  • Horseshoe crabs
  • The Horseshoe crab
  • A Horseshoe crab tale
  • Fossil xiphosuran publications
  • Prehistoric animals still alive
  • The origin of the horseshoe crab
  • Elvis and Matilda (dogs and crabs!)
  • Geocities Horseshoe crab page
  • Gerald S. Wassermann
  • Pennsylvania State University
  • Horseshoe Crab (Assateague Naturalists)
  • Horseshoe crab
  • Subphylum Chelicerata
  • Arthropod fossils of Kentucky
  • Daniel G. Gibson III
  • Horsshoe Crab Limulus (pencil drawing)
  • Horseshoe 'crab'(systematics)
  • The Skull Site (painted Limulus!)
  • Solnhofen fossils
  • Alternative Sources of LAL
  • for those of you more interested in eurypterids (an extinct aquatic chelicerate), here's a few for you!

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    Xiphosurans are marine aquatic arthropods which are grouped with the Chelicerates. Other more familiar Chelicerates include spiders and scorpions (arachnids), and eurypterids (extinct aquatic arthropods). As more and more sites yielding exceptionally preserved fossil arthropods turn up in rocks of Cambrian age, it seems less likely that xiphosurans and trilobites shared a common ancestor. There are far too many other better suited candidates.

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    Taphonomy of Xiphosurans

    Xiphosurans in common with other chelicerates have an unmineralised exoskeleton of chitinous cuticle. This is quite unlike the calcium carbonate armour of trilobites. Consequently, their remains behave slightly differently during fossil diagenesis. Whereas trilobites have a widespread occurrence through many different sediments representing different depositional settings, xiphosuran fossils are much more restricted in their occurrence. In fact, they are most often associated with sites of exceptional preservation, so-called Konservat-Lagerstatten.

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    This listing is modified from a recent research paper which I co-authored with my research supervisor, Dr Paul A. Selden. I have included here the classification down to species level. However, fossils just keep getting found so the list is bound to increase! The Palaeozoic Xiphosura