Carcinosomatidae

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Carcinosomatidae
Temporal range: Late Ordovician - Early Devonian, 449–412.3  Ma
Eusarcana scorpionis fossil.png
Fossil of Eusarcana
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Chelicerata
Order:† Eurypterida
Infraorder:† Diploperculata
Superfamily:† Carcinosomatoidea
Family:† Carcinosomatidae
Størmer, 1934
Type species
† Carcinosoma newlini
(Claypole, 1890)
Genera

Carcinosomatidae (the name deriving from the type genus Carcinosoma , meaning "crab body") [1] [2] is a family of eurypterids, an extinct group of aquatic arthropods. They were members of the superfamily Carcinosomatoidea, also named after Carcinosoma. Fossils of carcinosomatids have been found in North America, Europe and Asia, the family possibly having achieved a worldwide distribution, and range in age from the Late Ordovician to the Early Devonian. They were among the most marine eurypterids, known almost entirely from marine environments.

Contents

Carcinosomatids varied considerably in size, from species only a few centimetres in length to some of the largest known arthropods. The largest carcinosomatid species, Carcinosoma punctatum, reached lengths of at least 2.2 metres (7.2 ft) and rivalled the largest eurypterid of all, Jaekelopterus , in size. Morphologically, carcinosomatids were highly distinct from other eurypterids, known for their powerful and spiny set of forelimbs, a broad and rounded central body and a slender and tubular tail ending in a telson (the posteriormost division of the body) that was typically curved in some way. With these adaptations, the carcinosomatids were quite similar to scorpions, and the group may have helped contribute to the common name of eurypterids becoming 'sea scorpions'. The family contains four, possibly five, genera: Carcinosoma, Eocarcinosoma , Eusarcana , Rhinocarcinosoma and possibly the problematic genus Holmipterus .

It is unlikely that the carcinosomatids were strong and active swimmers, given their non-streamlined shape. It is more probable that they were nektobenthic (swimming near the bottom), possibly being top predators (given their size) or scavengers, digging for food or perhaps even burrowing and lying in wait as ambush predators.

Description

Reconstruction of Carcinosoma Carcinosoma newlini.png
Reconstruction of Carcinosoma

Carcinosomatid eurypterids differed considerably in size depending on the genus and species, [3] though most species were quite large. [4] The largest species was Carcinosoma punctatum at 2.2 metres (7.2 ft), one of the largest eurypterids of all, with some specimens suggesting that it may even have reached lengths of 2.5 metres (8.2 ft), rivalling Jaekelopterus , the largest eurypterid, in size. [3] [5] The smallest carcinosomatid species was Eusarcana obesus, at 4 centimetres (1.5 in) in length. [3] [lower-alpha 1]

Morphologically, the carcinosomatids were highly distinct among the eurypterids. They were swimming eurypterids (belonging to the suborder Eurypterina), with large swimming paddles, a set of powerful and spiny forelimbs, a broad and rounded preabdomen (central body) and a slender, [4] tubular abdomen, [9] which ended in a telson (the posteriormost division of the body) of variable morphology, [10] [11] often curved. [4] [10] In a sense, the carcinosomatids were rather scorpion-like in appearance, [4] [12] and may have contributed to the common name of eurypterids having become 'sea scorpions'. [4]

There was considerable variety in morphology within the group. The carapace was triangular to subtriangular in shape in all members of the group, through the exact shape could vary. [7] In Rhinocarcinosoma , there was a distinctive, shovel-shaped protrusion at the front of the carapace. [13] The preabdomen was wide in all species, but the width also differed from species to species. The widest species, relatively speaking, was Eusarcana obesus, in which the fourth segment was as wide as the first eight segments combined were long. [14] The spinosity (how many spines) and size of the forelimbs also varied from genus to genus, with the forelimbs of Eusarcana for instance being more powerful than those of Rhinocarcinosoma. [10] The telson varied considerably between genera: in Rhinocarcinosoma it was robust and flattened, curving slightly upwards, [10] in Eusarcana it was cylindrical and fashioned into a sharp, scorpion-like tail spike [6] and in Carcinosoma it was flattened, ending in an expanded and segmented structure unseen in other eurypterids. [11]

History of research

Carapaces of Rhinocarcinosoma, as figured by John Mason Clarke and Rudolf Ruedemann in 1912 The Eurypterida of New York figure 108-110.jpg
Carapaces of Rhinocarcinosoma , as figured by John Mason Clarke and Rudolf Ruedemann in 1912

The earliest carcinosomatid species to be described was Carcinosoma punctatum, first described under the name Pterygotus punctatus by John William Salter in 1859. [15] The earliest genus later seen as a carcinosomatid to be described was Eusarcus (and its type species E. scorpionis), described by August R. Grote and William Henry Pitt in 1875 based on fossils recovered from the Pridoli-age Buffalo Waterlime of New York State. The description of the genus was lacking and seemingly based only on the outline and shape of the fossil, which led Henry Woodward to refer E. scorpionis to Eurypterus on the grounds that it was similar in shape to Eurypterus punctatus (Pterygotus punctatus having been reclassified as a species of Eurypterus). Unbeknownst to Grote and Pitt, Eusarcus had already been named as a genus of extant (currently living) laniatorid harvestmen of the family Gonyleptidae, in 1833 and as such constituted a preoccupied name. The name being preoccupied went unnoticed until the 1930s. [4] Also described in the late 19th century was the genus Eurysoma, named alongside its type species, E. newlini, by Edward Waller Claypole in 1890. When Claypole discovered later in 1890 that the name was preoccupied by a genus of modern beetles, he replaced the name Eurysoma with the name Carcinosoma. [16]

In 1912, John Mason Clarke and Rudolf Ruedemann declared that the differences between Eusarcus and all related forms of eurypterids were so great that it was "entirely evident" that Eusarcus was distinct from other eurypterids. Clarke and Ruedemann referred several new species to Eusarcus, including new species that would later be seen as species of the genus Rhinocarcinosoma, and also concluded that Eusarcus was sufficiently similar to Carcinosoma to be synonymised. Because Eusarcus had been named earlier than Carcinosoma, the taxonomical laws of priority dictated that Eusarcus would be the name of the taxon. [4]

Eusarcus was finally recognised as a preoccupied name by Leif Størmer in 1934. Størmer substituted the name for the next oldest available non-preoccupied synonym, Carcinosoma. Størmer also introduced the family Carcinosomatidae, initially under the name 'Carcinosomidae', in 1934, to contain the four genera Carcinosoma, Mixopterus , Echinognathus and Megalograptus . The family was amended by Erik N. Kjellesvig-Waering in Størmer's 1955 Treatise on Invertebrate Paleontology , with the name changed to the correct Carcinosomatidae and the genera other than Carcinosoma transferred to their own families (Mixopterus to the Mixopteridae and Megalograptus and Echinognathus to the Megalograptidae). In 1942, Embrik Strand proposed another replacement name for Eusarcus, Eusarcana, despite the matter having been dealt with by Størmer eight years prior. [4] Rhinocarcinosoma was split off from Carcinosoma in 1962 by Nestor Ivanovich Novozhilov, based on its carapace being different from that of other Carcinosoma. [10]

Comparison of the sizes of the three largest species of the genera Carcinosoma, Eusarcana and Rhinocarcinosoma and a human Carcinosomatidae Scale.svg
Comparison of the sizes of the three largest species of the genera Carcinosoma , Eusarcana and Rhinocarcinosoma and a human

When revising the carcinosomatids in 1964, Kenneth Edward Caster and Erik N. Kjellesvig-Waering recognised Eusarcus and Carcinosoma to be distinct genera, determining the 1912 synonymisation to have been erroneous. Since Eusarcus was preoccupied, Caster and Kjellesvig-Waering, likely unaware of Strand's Eusarcana, coined the replacement name Paracarcinosoma for the species previously referred to Eusarcus. [4] Also in 1964, Caster and Kjellesvig-Waering named the new genus Eocarcinosoma to account for Ordovician specimens of Eusarcus/Paracarcinosoma. [17] Though most of those specimens have since been identified as pseudofossils, [18] the type specimen of Eocarcinosoma is an authentic fossil [19] and the earliest record of the family. [20] The known geographical range of the carcinosomatids was considerably extended with the discovery of Rhinocarcinosoma fossils in Vietnam in the late 20th century, [21] named as the species R. dosonensis in 2002. [10]

Though Paracarcinosoma was frequently used by later researchers, Eusarcana, named earlier, was recognised by Jason A. Dunlop and James Lamsdell in 2012 as the valid replacement name of Eusarcus, transferring the species assigned to Paracarcinosoma to that genus and designating Paracarcinosoma as a junior synonym. [4] A 2015 phylogenetic analysis by Lamsdell and colleagues recovered Holmipterus , a problematic eurypterid genus of uncertain affinities, as a basal carcinosomatid. [22] The position of Holmipterus, on account of incomplete fossil material and an apparent combination of traits from different families, [23] is far from certain within the eurypterid family tree and its fossils may even represent two different genera, mistakenly grouped together. [24]

Classification

Mixopterids, such as Mixopterus (pictured), were the closest relatives of the carcinosomatids Mixopterus BW.jpg
Mixopterids, such as Mixopterus (pictured), were the closest relatives of the carcinosomatids

The carcinosomatids are classified as part of the superfamily Carcinosomatoidea, within the infraorder Diploperculata. [20] The Carcinosomatoidea also contains the families Mixopteridae [20] and Megalograptidae. [22] Carcinosomatidae was previously, from 1989 [24] to the early 2000s, [25] grouped with the family Hughmilleriidae in the superfamily 'Hughmillerioidea', on account of the spined limbs and all limbs, with the exception of the swimming paddles, being of a consistent type. [24] The Hughmilleriidae is today regarded as basal members of the superfamily Pterygotioidea. [26]

The internal phylogeny of the Carcinosomatoidea is poorly resolved (unclear). [12] The first cladogram below follows a 2007 study by eurypterid researcher O. Erik Tetlie, which was in turn based on results from various phylogenetic analyses on eurypterids conducted between 2004 and 2007, [12] whereas the second cladogram follows a 2015 study by James Lamsdell and colleagues. [22] Both cladograms have been simplified to only display the Carcinosomatoidea. Tetlie (2007) recovered the Carcinosomatidae as a paraphyletic grouping, accounting for basal members of the Carcinosomatoidea, [12] whereas Lamsdell et al. (2015) recovered the carcinosomatids as a monophyletic group. [22]

Palaeoecology

Model of a Eusarcana on a Silurian seafloor Diorama of a Silurian seafloor - eurypterid 2 (31834971848).jpg
Model of a Eusarcana on a Silurian seafloor

Carcinosomatid eurypterids were among the most marine eurypterids, [21] known from deposits that were once reefs, some in lagoonal settings, [13] and deeper waters. [12] This is in sharp contrast to their closest relatives, the mixopterids, which are not known from deeper waters. The only other eurypterid family known from deeper waters are the pterygotids, which had a similar distribution to the carcinosomatids, albeit more successful. Based on the distribution of the pterygotids, it is possible that carcinosomatids ranged worldwide. They are, alongside the pterygotids, the only eurypterid family known from the southern continent of Gondwana in the Silurian and Devonian. [12] The only carcinosomatid genus known from non-marine deposits is Rhinocarcinosoma (though it is also known marine deposits), which has been found in fluvial (river) and lacustrine (lake) settings as well. [21]

Because of their bodies not being as streamlined as those of many other swimming eurypterids, and on account of the unique morphologies of their telsons, it is considered likely that the carcinosomatids were not very active swimmers, probably adopting a more nektobenthic (swimming near the bottom) lifestyle. [15] This lifestyle is especially exemplified in Rhinocarcinosoma, where the shovel-like protrusion at the front of its carapace may have been used for digging, or "mud-grubbing", and the swimming paddles were reduced in size compared to those of other carcinosomatids. [21] Given their size, carcinosomatids may have been top predators or scavengers, digging for food or perhaps even burrowing and lying in wait as ambush predators. They may have fed on worms, other arthropods, brachiopods and fish, using their forelimbs to push food into their mouths. [21]

See also

Notes

  1. ↑ The largest fossil specimens of the species Rhinocarcinosoma cicerops are also 4 centimetres in length, [3] but the known fossils represent juvenile specimens. [6] Eocarcinosoma batrachophthalmus was also very small, but it would have exceeded 4 centimetres in length given that its head was 2.05 centimetres (0.8 in) long. [7] It is also possible that Eusarcana obesus is a juvenile form of the species Carcinosoma scorpioides, [8] in which case Eocarcinosoma batrachophthalmus would be the smallest carcinosomatid. [3]

Related Research Articles

<span class="mw-page-title-main">Eurypterid</span> Order of arthropods (fossil)

Eurypterids, often informally called sea scorpions, are a group of extinct arthropods that form the order Eurypterida. The earliest known eurypterids date to the Darriwilian stage of the Ordovician period 467.3 million years ago. The group is likely to have appeared first either during the Early Ordovician or Late Cambrian period. With approximately 250 species, the Eurypterida is the most diverse Paleozoic chelicerate order. Following their appearance during the Ordovician, eurypterids became major components of marine faunas during the Silurian, from which the majority of eurypterid species have been described. The Silurian genus Eurypterus accounts for more than 90% of all known eurypterid specimens. Though the group continued to diversify during the subsequent Devonian period, the eurypterids were heavily affected by the Late Devonian extinction event. They declined in numbers and diversity until becoming extinct during the Permian–Triassic extinction event 251.9 million years ago.

<i>Eurypterus</i> Extinct genus of sea scorpions

Eurypterus is an extinct genus of eurypterid, a group of organisms commonly called "sea scorpions". The genus lived during the Silurian period, from around 432 to 418 million years ago. Eurypterus is by far the most well-studied and well-known eurypterid. Eurypterus fossil specimens probably represent more than 95% of all known eurypterid specimens.

<i>Pterygotus</i> Extinct genus of eurypterid

Pterygotus is a genus of giant predatory eurypterid, a group of extinct aquatic arthropods. Fossils of Pterygotus have been discovered in deposits ranging in age from Middle Silurian to Late Devonian, and have been referred to several different species. Fossils have been recovered from four continents; Australia, Europe, North America and South America, which indicates that Pterygotus might have had a nearly cosmopolitan (worldwide) distribution. The type species, P. anglicus, was described by Swiss naturalist Louis Agassiz in 1839, who gave it the name Pterygotus, meaning "winged one". Agassiz mistakenly believed the remains were of a giant fish; he would only realize the mistake five years later in 1844.

<i>Megalograptus</i> Extinct genus of arthropods

Megalograptus is a genus of eurypterid, an extinct group of aquatic arthropods. Fossils of Megalograptus have been recovered in deposits of Katian age in North America. The genus contains five species: M. alveolatus, M. ohioensis, M. shideleri, M. welchi and M. williamsae, all based on fossil material found in the United States. Fossils unassigned to any particular species have also been found in Canada. The generic name translates to "great writing" and originates from the mistaken original belief that Megalograptus was a type of graptolite, often given names ending with -graptus.

<i>Carcinosoma</i> Extinct genus of arthropods

Carcinosoma is a genus of eurypterid, an extinct group of aquatic arthropods. Fossils of Carcinosoma are restricted to deposits of late Silurian age. Classified as part of the family Carcinosomatidae, which the genus lends its name to, Carcinosoma contains seven species from North America and Great Britain.

<i>Brachyopterus</i> Extinct genus of sea scorpions

Brachyopterus is a genus of prehistoric eurypterid of the family Rhenopteridae. It is one of the earliest known eurypterids, having been recovered from Middle Ordovician deposits in Montgomeryshire, Wales. Though other species have been assigned to it in the past, Brachyopterus is today recognized as containing one valid species, B. stubblefieldi.

<i>Drepanopterus</i> Extinct genus of sea scorpions

Drepanopterus is an extinct genus of eurypterid and the only member of the family Drepanopteridae within the Mycteropoidea superfamily. There are currently three species assigned to the genus. The genus has historically included more species, with nine species having been associated with the genus Drepanopterus. Five of these have since been proven to be synonyms of pre-existing species, assigned to their own genera, or found to be based on insubstantial fossil data. The holotype of one species proved to be a lithic clast.

<i>Holmipterus</i> Extinct genus of arthropods

Holmipterus is a problematic genus of eurypterid, an extinct group of aquatic arthropods. The type and only species of Holmipterus, H. suecicus, is known from deposits of Middle Silurian age in the Sweden. The generic name honours Gerhard Holm, a renowned Swedish palaeontologist specialising in arthropods and crustaceans, and the species name suecicus is Latin for 'Swedish'.

<i>Eocarcinosoma</i> Extinct genus of arthropods

Eocarcinosoma is a genus of eurypterid, an extinct group of aquatic arthropods. The type and only species of Eocarcinosoma, E. batrachophthalmus, is known from deposits of Late Ordovician age in the United States. The generic name is derived from the related genus Carcinosoma, and the Greek eós meaning 'dawn', referring to the earlier age of the genus compared to other carcinosomatid eurypterids.

<i>Echinognathus</i> Extinct genus of arthropods

Echinognathus is a genus of eurypterid, an extinct group of aquatic arthropods. The type and only species of Echinognathus, E. clevelandi, is known from deposits of Late Ordovician age in the United States. The generic name is derived from the Neo-Latin echino- ("spiny") and the Greek gnáthos ("jaw"), in reference to a spiny endognathary appendage part of the fossil type material.

<i>Rhinocarcinosoma</i> Extinct genus of eurypterids

Rhinocarcinosoma is a genus of eurypterid, an extinct group of aquatic arthropods. Fossils of Rhinocarcinosoma have been discovered in deposits ranging of Late Silurian age in the United States, Canada and Vietnam. The genus contains three species, the American R. cicerops and R. vaningeni and the Vietnamese R. dosonensis. The generic name is derived from the related genus Carcinosoma, and the Greek ῥινός, referring to the unusual shovel-shaped protrusion on the front of the carapace of Rhinocarcinosoma, its most distinctive feature.

<i>Parahughmilleria</i> Extinct genus of arthropods

Parahughmilleria is a genus of eurypterid, an extinct group of aquatic arthropods. Fossils of Parahughmilleria have been discovered in deposits of the Devonian and Silurian age in the United States, Canada, Russia, Germany, Luxembourg and Great Britain, and have been referred to several different species. The first fossils of Parahughmilleria, discovered in the Shawangunk Mountains in 1907, were initially assigned to Eurypterus. It would not be until 54 years later when Parahughmilleria would be described.

<span class="mw-page-title-main">Pterygotioidea</span> Extinct superfamily of eurypterids

Pterygotioidea is a superfamily of eurypterids, an extinct group of aquatic arthropods. Pterygotioids were the most derived members of the infraorder Diploperculata and the sister group of the adelophthalmoid eurypterids. The group includes the basal and small hughmilleriids, the larger and specialized slimonids and the famous pterygotids which were equipped with robust and powerful cheliceral claws.

<span class="mw-page-title-main">Stylonuroidea</span> Extinct superfamily of arthropods

Stylonuroidea is an extinct superfamily of eurypterids, an extinct group of chelicerate arthropods commonly known as "sea scorpions". It is one of four superfamilies classified as part of the suborder Stylonurina.

<span class="mw-page-title-main">Adelophthalmidae</span> Family of eurypterids, an extinct group of aquatic arthropods

Adelophthalmidae is a family of eurypterids, an extinct group of aquatic arthropods. Adelophthalmidae is the only family classified as part of the superfamily Adelophthalmoidea, which in turn is classified within the infraorder Diploperculata in the suborder Eurypterina.

<span class="mw-page-title-main">Eurypterina</span> Suborder of eurypterid

Eurypterina is one of two suborders of eurypterids, an extinct group of chelicerate arthropods commonly known as "sea scorpions". Eurypterine eurypterids are sometimes informally known as "swimming eurypterids". They are known from fossil deposits worldwide, though primarily in North America and Europe.

<span class="mw-page-title-main">Mycteropoidea</span> Extinct superfamily of arthropods

Mycteropoidea is an extinct superfamily of eurypterids, an extinct group of chelicerate arthropods commonly known as "sea scorpions". It is one of four superfamilies classified as part of the suborder Stylonurina. Mycteropoids have been recovered from Europe, Russia, South America and South Africa. Mycteropoid specimens are often fragmentary, making it difficult to establish relationships between the included taxa. Only two mycteropoid taxa are known from reasonable complete remains, Hibbertopterus scouleri and H. wittebergensis.

<i>Eusarcana</i> Extinct genus of sea scorpions

Eusarcana is a genus of eurypterid, an extinct group of aquatic arthropods. Fossils of Eusarcana have been discovered in deposits ranging in age from the Early Silurian to the Early Devonian. Classified as part of the family Carcinosomatidae, the genus contains three species, E. acrocephalus, E. obesus and E. scorpionis, from the Silurian-Devonian of Scotland, the Czech Republic and the United States respectively.

<i>Ciurcopterus</i> Extinct genus of arthropods

Ciurcopterus is a genus of eurypterid, an extinct group of aquatic arthropods. Fossils of Ciurcopterus have been discovered in deposits of Late Silurian age in North America. Classified as part of the family Pterygotidae, the genus contains two species, C. sarlei from Pittsford, New York and C. ventricosus from Kokomo, Indiana. The genus is named in honor of Samuel J. Ciurca, Jr., who has contributed significantly to eurypterid research by discovering a large amount of eurypterid specimens, including the four specimens used to describe Ciurcopterus itself.

<span class="mw-page-title-main">Timeline of eurypterid research</span>

This timeline of eurypterid research is a chronologically ordered list of important fossil discoveries, controversies of interpretation, and taxonomic revisions of eurypterids, a group of extinct aquatic arthropods closely related to modern arachnids and horseshoe crabs that lived during the Paleozoic Era.

References

  1. ↑ Meaning of cancer at www.dictionary.com. Retrieved 7 September 2018.
  2. ↑ Meaning of soma at www.dictionary.com. Retrieved 7 September 2018.
  3. 1 2 3 4 5 Lamsdell, James C.; Braddy, Simon J. (2009). "Cope's rule and Romer's theory: patterns of diversity and gigantism in eurypterids and Palaeozoic vertebrates". Biology Letters . 6 (2): 265–269. doi:10.1098/rsbl.2009.0700. ISSN   1744-9561. PMC   2865068 . PMID   19828493. Supplemental material.
  4. 1 2 3 4 5 6 7 8 9 10 Dunlop, Jason A.; Lamsdell, James C. (2012). "Nomenclatural notes on the eurypterid family Carcinosomatidae". Zoosystematics and Evolution. 88 (1): 19–24. doi:10.1002/zoos.201200003. ISSN   1860-0743.
  5. ↑ Kjellesvig-Waering, Erik N. (1961). "The Silurian Eurypterida of the Welsh Borderland". Journal of Paleontology. 35 (4): 789–835. JSTOR   1301214.
  6. 1 2 Clarke, John M.; Ruedemann, Rudolf (1912). The Eurypterida of New York. University of California Libraries. ISBN   978-1125460221.
  7. 1 2 Caster, Kenneth E.; Kjellesvig-Waering, Erik N. (1964). "Upper Ordovician eurypterids of Ohio". Paleontological Research Institution. 4.
  8. ↑ James, Lamsdell (2014-05-31). "Selectivity in the evolution of Palaeozoic arthropod groups, with focus on mass extinctions and radiations: a phylogenetic approach".{{cite journal}}: Cite journal requires |journal= (help)
  9. ↑ Kjellesvig-Waering, Erik N. (1979). "Eurypterids" (PDF). In Laufeld, Sven; Skoglund, Roland (eds.). Lower Wenlock faunal and floral dynamics – Vattenfallet section, Gotland (PDF). Geological Survey of Sweden. pp. 121–136. ISBN   9171581707.
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  14. ↑ Woodward, Henry (1868). "On some New Species of Crustacea from the Upper Silurian Rocks of Lanarkshire &c.; and further observations on the Structure of Pterygotus". Quarterly Journal of the Geological Society. 24 (1–2): 289–296. doi:10.1144/GSL.JGS.1868.024.01-02.36. ISSN   0370-291X. S2CID   128874377.
  15. 1 2 Gladwell, David Jeremy (2005). "The biota of Upper Silurian submarine channel deposits, Welsh Borderland". Theses, Leicester University Dept. Of Geology.
  16. ↑ Kjellesvig-Waering, Erik N. (1958). "Some Previously Unknown Morphological Structures of Carcinosoma newlini (Claypole)". Journal of Paleontology. 32 (2): 295–303. JSTOR   1300736.
  17. ↑ Caster, Kenneth E.; Kjellesvig-Waering, Erik N. (1964). "Upper Ordovician eurypterids of Ohio". Paleontological Research Institution. 4.
  18. ↑ Tollerton, Victor P. (2003). "Summary of a revision of New York State Ordovician eurypterids: implications for eurypterid palaeoecology, diversity and evolution". Earth and Environmental Science Transactions of the Royal Society of Edinburgh. 94 (3): 235. doi:10.1017/s0263593303000154. ISSN   0263-5933.
  19. ↑ Braddy, Simon J.; Tollerton, Victor P.; Racheboeuf, Patrick R.; Schallreuter, Roger (2004). 25. Eurypterids, Phyllocarids, and Ostracodes. Columbia University Press. doi:10.7312/webb12678-026. ISBN   978-0-231-50163-7.
  20. 1 2 3 Dunlop, J. A., Penney, D. & Jekel, D. 2018. A summary list of fossil spiders and their relatives. In World Spider Catalog. Natural History Museum Bern
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  22. 1 2 3 4 Lamsdell, James C.; Briggs, Derek E. G.; Liu, Huaibao; Witzke, Brian J.; McKay, Robert M. (September 1, 2015). "The oldest described eurypterid: a giant Middle Ordovician (Darriwilian) megalograptid from the Winneshiek Lagerstätte of Iowa". BMC Evolutionary Biology . 15: 169. doi: 10.1186/s12862-015-0443-9 . PMC   4556007 . PMID   26324341.
  23. ↑ Kjellesvig-Waering, Erik N. (1979). "Eurypterids" (PDF). In Laufeld, Sven; Skoglund, Roland (eds.). Lower Wenlock faunal and floral dynamics – Vattenfallet section, Gotland (PDF). Geological Survey of Sweden. pp. 121–136. ISBN   9171581707.
  24. 1 2 3 Tollerton, Victor P. (1989). "Morphology, taxonomy, and classification of the order Eurypterida Burmeister, 1843". Journal of Paleontology. 63 (5): 642–657. doi:10.1017/S0022336000041275. ISSN   0022-3360. S2CID   46953627.
  25. ↑ Stott, Christopher A.; Tetlie, O. Erik; Braddy, Simon J.; Nowlan, Godfrey S.; Glasser, Paul M.; Devereux, Matthew G. (2005). "A new eurypterid (Chelicerata) from the Upper Ordovician of Manitoulin Island, Ontario, Canada". Journal of Paleontology. 79 (6): 1166–1174. doi:10.1666/0022-3360(2005)079[1166:ANECFT]2.0.CO;2. ISSN   0022-3360. S2CID   55014027.
  26. ↑ Tetlie, O. Erik; Briggs, Derek E. G. (2009). "The origin of pterygotid eurypterids (Chelicerata: Eurypterida)". Palaeontology. 52 (5): 1141–1148. doi: 10.1111/j.1475-4983.2009.00907.x . ISSN   1475-4983.
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