Nanahughmilleria

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Nanahughmilleria
Temporal range: Llandovery-Eifelian, 435–387.7  Ma
The Eurypterida of New York figure 38.jpg
Carapace of N. prominens
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Chelicerata
Order:† Eurypterida
Superfamily:† Adelophthalmoidea
Family:† Adelophthalmidae
Genus:† Nanahughmilleria
Kjellesvig-Waering, 1961
Type species
†Nanahughmilleria norvegica
Kiær, 1911
Species
  • †N. clarkeiKjellesvig-Waering, 1964
  • †?N. lanceolataSalter, 1856
  • †N. norvegicaKiær, 1911
  • †N. notosibiricaShpiney, 2012
  • †?N. prominensHall, 1884
  • †N. pygmaeaSalter, 1859
  • †?N. schiraensisPirozhnikov, 1957

Nanahughmilleria ("dwarf Hughmilleria ") is a genus of eurypterid, an extinct group of aquatic arthropods. Fossils of Nanahughmilleria have been discovered in deposits of Devonian and Silurian age in the United States, Norway, Russia, England and Scotland, and have been referred to several different species.

Contents

Nanahughmilleria is classified in the family Adelophthalmidae, the only clade in the superfamily Adelophthalmoidea. This clade was characterised by their small size, their parabolic (approximately U-shaped) carapaces and the presence of epimera (lateral "extensions" of the segment) on the seventh segment, among others. Nanahughmilleria was different from its relatives by the presence of more spines in its appendages (limbs) and by its genital morphology. The largest species confidently assigned to the genus was N. norvegica at 10 cm (3.9 in), making it a comparatively small eurypterid.

Description

Restoration of N. norvegica. Nanahughmilleria norvegica restoration.png
Restoration of N. norvegica.

Like the other adelophthalmid eurypterids, Nanahughmilleria was a comparatively small eurypterid. The largest species confidently assigned to the genus, N. norvegica, only reached 10 cm (3.9 in), while the smallest one, N. clarkei, did not exceed 4 cm (1.6 in). [1] Although N. lanceolata reached 16 cm (6.3 in), [1] this species is probably not an adelophthalmid, but an eurypteroid. [2] Other species such as N. notosibirica reached 9 cm (3.5 in) in length, while N. pygmaea had a total length of 8 cm (3.1 in). [1]

Nanahughmilleria had long and narrow reniform (bean-shaped) eyes placed in an intramarginal (occurring within the margin) position. The streamlined form of its body indicates that Nanahughmilleria was an active swimmer adapted to swim crosscurrent. [3] [2] It had epimera (lateral "extensions" of the segment) present in the seventh segment, separating the preadomen (body segments 1 to 7) from the postabodmen (segments 8 to 12). The genital spatulae, a long, flat piece in the genital aperture, was very short. The walking legs (first to fifth appendages) of Nanahughmilleria were probably of Hughmilleria -type, that is, with a pair of spines in each podomere (leg segment). The paddle of the swimming leg was relatively wide. [4] As in the other adelophthalmids, the telson was lanceolate and not very expanded. [5]

Nanahughmilleria is only distinguished from the more derived members of Adelophthalmidae in the shorter and smaller spatulae and in the increased spinosity in the appendages. [4]

History of research

First discoveries

Size comparison of the unequivocal Nanahughmilleria species. Nanahughmilleria Size.svg
Size comparison of the unequivocal Nanahughmilleria species.

The first species of what today is recognized as Nanahughmilleria was described in 1859 by John William Salter as " Eurypterus pygmaeus ". Although Richard Banks first mentioned this species in 1856, this act is currently considered as nomen nudum ("naked name", a name coined without an adequate or completely missing description of it). The fossils mentioned by Banks consisted of two specimens, the first of which included carapace with the first five tergites (dorsal parts of the body segments) and the 8th and 9th segments of the swimming leg and the second including another nearly complete carapace. Both were collected in Kington, Herefordshire. N. pygmaea had an elongated carapace rounded along the anterior margin which narrows gradually anteriorly. A thin rim surrounded the carapace. The eyes were narrow, reniform and intramarginal. Its ocelli (light-sensitive simple eyes) were very small and located centrally. As in most eurypterid groups, the chelae (pincers) were small. It differs from other species in the more convergent form of the carapace and in the large size of the eyes, which were furthest from the margin. [3] This species reached a length of 8 cm (3.1 in) in total. [1] Erik N. Kjellesvig-Waering classified this species as part of the subgenus Hughmilleria (Nanahughmilleria) in 1961 along many other species. [3]

In 1884, James Hall described another species of Eurypterus, E. prominens, based on a single carapace from the Clinton Group, a geological formation of the United States. This species differs from the others by the anterior position of its eyes placed in a submarginal (almost in the margin) point, unlike other species of Nanahughmilleria and Parahughmilleria . [2] In addition, the carapace of this species was long and with ocelli placed forward. [6] It has been suggested that this species could represent a separate genus. [2] In fact, notes left by Kjellesvig-Waering in museum drawers indicate that he wanted to erect a new genus for N. prominens, Clintonipterus. [7] As in N. pygmaea, this species was assigned to Nanahughmilleria in 1961. [3]

In 1911, the Norwegian paleontologist and geologist Johan Aschehoug Kiær described a new species of Eurypterus, E. norvegica. The carapace of this species was parabolic (approximately U-shaped) with small intramarginal arcuate eyes. The metastoma (a large plate that is part of the abdomen) was oval. Its operculum (a plate-like segment which contains the genital aperture) had a long, narrow spatulae (compared to most eurypterids). The telson was lanceolate, with a keel on both dorsal and ventral sides. [7] It had a pair of spines in each podomere of the fifth appendage. The paddle of the swimming leg was relatively wide. [2] It was designated the type species of Nanahughmilleria by Kjellesvig-Waering in his description of the subgenus. [3] N. norvegica was the largest species of Nanahughmilleria, measuring 10 cm (3.9 in, with the exception of N. lanceolata, which may represent a separate genus). [2]

In 1957, L. P. Pirozhnikov described two new species of eurypterids, N. schiraensis and Parahughmilleria matarakensis, and erroneously assigned them to the stylonurine genus Rhenopterus . This species is only known by a poorly preserved carapace which was semi-oval and elongated, with a narrow margin surrounding it. The posterior margin was slightly concave. There is only one preserved eye, which was reniform, large and rose slightly from the surface of the carapace. At the closest point between both eyes, the ocelli were placed. The fossils were found at the Matarak Formation in Minusinsk, Siberia. [8] Kjellesvig-Waering and Willard P. Leutze noticed that the species did not really represent a Rhenopterus and they assigned it in 1966 to its current genus. [9] It has been suggested that this species is a synonym of P. matarakensis, [2] but the Russian paleontologist Evgeniy S. Shpinev does not agree with this since the prosoma of N. schiraensis was longer and its eyes were closer to the margin than in P. matarakensis. [10]

Creation of the subgenus and further discoveries

Fossils of N. clarkei previously assigned to Hughmilleria shawangunk. Nanahughmilleria clarkei Eurypterida of New York.png
Fossils of N. clarkei previously assigned to Hughmilleria shawangunk.

In 1961, Kjellesvig-Waering separated Hughmilleria into two subgenera according to the morphology of the eyes, H. (Hughmilleria) for species with large ovoid marginal eyes and H. (Nanahughmilleria) for species with small reniform intramarginal eyes. For the latter one, H. (N.) norvegica was designated as subgenotype. He assigned a total of seven species to the subgenus, of which only four (two of them tentatively) are still in Nanahughmilleria. [3] The generic name is composed by the Latin word nana ("dwarf") and Hughmilleria. [11]

N. clarkei is based on a series of fossils described and assigned to Hughmilleria shawangunk by John Mason Clarke and Rudolf Ruedemann in 1912. They believed that the carapaces with intramarginal eyes were modified by the compression. While this could happen in a single specimen, it is impossible to be in so many. Kjellesvig-Waering realized this and erected the species N. clarkei in 1964, named after Clarke, who described the original Shawangunk eurypterid fauna. [12] This small species of only 4 cm (1.6 in) [1] had a lanceolate carapace with intramarginal eyes located anteriorly. The telson was broad and lanceolate. This species is characterized by the presence of spurs in the genal angles (a "flat" part of the carapace edge). [12]

It would not be until 2012 when another new species, N. notosibirica, was described by Shpinev. This species is known from two specimens, the holotype (PIN 1139/1) and paratype (PIN 1139/2). Its specific name, notosibirica, comes from the Greek word notos (southern) and Siberia, referring to the place where it was discovered. The carapace was parabolic and surrounded by a narrow marginal rim and with elongated eyes probably reniform. Only the fourth and fifth pair of prosomal appendages is known. These were of Hughmilleria-type and with rather small spines. The telson was small and wedge-shaped, known from fragmentary remains. The metasoma (the posterior "part" of the body) was notably narrower than the mesosoma (the "median part"). The total size of the species could be of 9 cm (3.5 in), being one of the largest species of Nanahughmilleria. This species differs from the others in the proportions of the body and position of the eyes. [10]

In addition, the species N. lanceolata is tentatively classified as part of Nanahughmilleria. This species was originally described by Salter in 1856 as another species of his new genus Himantopterus (a preoccupied name, now Erettopterus ). The swimming legs of this species were long and narrow, reaching the sixth segment of the body. The telson was lanceolate and with a keel in the middle. [13] All known specimens of N. lanceolata lack eyes, making it difficult to determine their phylogenetic position. However, the prosomal and genital appendages were not typical of the Adelophthalmoidea, but probably of the Eurypteroidea. [2]

Classification

Nanahughmilleria norvegica genital appendage.png
Pittsfordipterus phelpsae genital appendage.png
Type A genital appendages of Nanahughmilleria norvegica (top) and the closely related Pittsfordipterus phelpsae (bottom).

Nanahughmilleria is classified as part of the family Adelophthalmidae, the only family within the superfamily Adelophthalmoidea. [14] Nanahughmilleria was originally considered a subgenus of Hughmilleria, [3] but Kjellesvig-Waering and Leutze considered it sufficiently different from Hughmilleria and elevated the subgenus to the genus level. [9] It is the only polyphyletic genus (with grouped species that do not share an immediate common ancestor) of Adelophthlmidae, with the species N. prominens and N. lanceolata probably representing new and different forms. [2]

In 2004, O. Erik Tetlie erected the family Nanahughmilleridae in a thesis to contain the adelophthalmoids with no or reduced genital spatulae and the second to fifth pair of prosomal appendages of Hughmilleria-type. This family contained Nanahughmileria, Pittsfordipterus and perhaps Parahughmilleria. [7] However, the clade has almost never been used in subsequent studies and lists of eurypterids, [4] and instead, they classify the nanahughmillerids as part of Adelophthalmidae. [14] A basal clade between Bassipterus and Pittsfordipterus is better supported than the Nanahughmilleridae, while Nanahughmilleria is considered the sister taxon (closest relative) of the "derived clade" composed by Parahughmilleria and Adelophthalmus. [2] These eurypterids shared a series of characteristics such as the almost identical carapace, paddle, eye shapes and eye position. However, its short telson, thin cuticular sculpture (ornamentation consisting of small, minute, scales across the back), very small spatulae and increased spinosity in the appendages suggest a more basal position. [4] Before 2004, Nanahughmilleria was classified in the Hughmilleriidae family. [15]

The cladogram below presents the inferred phylogenetic positions of most of the genera included in the three most derived superfamilies of the Eurypterina suborder of eurypterids (Adelophthalmoidea, Pterygotioidea and the waeringopteroids), as inferred by O. Erik Tetlie and Markus Poschmann in 2008, based on the results of a 2008 analysis specifically pertaining to the Adelophthalmoidea and a preceding 2004 analysis. [2]

Diploperculata

Paleoecology

Fossils of Nanahughmilleria have been found from the Silurian deposits of the Llandovery epoch to the Devonian deposits of the Eifelian epoch in North America, Europe and Siberia. [16] It is believed that Nanahughmilleria, along with Parahughmilleria, Hughmilleria and the pterygotids, lived mainly in shallow lakes. [17] In addition, the streamlined shape of the body of Nanahughmilleria suggests that it was an active swimmer capable of swimming against currents. [3]

Nanahughmilleria can occur in an environment where eurypterids were abundant or scarce. The Silurian deposits of Ringerike, Norway, where fossils of N. norvegica have been discovered, include fossil remains of Mixopterus kiaeri , Stylonuroides dolichopteroides , Kiaeropterus ruedemanni and Erettopterus holmi, among other organisms like the malacostracan Dictyocaris slimoni or the chasmataspidid Kiaeria limuloides . [18] On the other hand, Nanahughmilleria schiraensis and Parahughmilleria matakarensis are the only animals of the Devonian deposits of Khakassia, Russia, together with land plants. [19] In addition, the English species N. pygmaea from the Silurian has been associated with Salteropterus abbreviatus , Parahughmilleria salteri, Erettopterus spatulatus and Herefordopterus banksii , as well as some indeterminate species of cephalaspidomorphs and coelolepids. [20] In the Silurian deposits of the Shawangunk Formation, Pennsylvania, N. clarkei occur together with Parahughmilleria maria, Ruedemannipterus stylonuroides , Hardieopterus myops and Hughmilleria shawangunk. Species of the gnathostomes Vernonaspis and Arthrophycus have also been found. [21] Nanahughmilleria fossils have also been found in Scotland. [22]

See also

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>Slimonia</i> Extinct genus of arthropods

Slimonia is a genus of eurypterid, an extinct group of aquatic arthropods. Fossils of Slimonia have been discovered in deposits of Silurian age in South America and Europe. Classified as part of the family Slimonidae alongside the related Salteropterus, the genus contains three valid species, S. acuminata from Lesmahagow, Scotland, S. boliviana from Cochabamba, Bolivia and S. dubia from the Pentland Hills of Scotland and one dubious species, S. stylops, from Herefordshire, England. The generic name is derived from and honors Robert Slimon, a fossil collector and surgeon from Lesmahagow.

<i>Hughmilleria</i> Genus of extinct arthropods

Hughmilleria is a genus of eurypterid, an extinct group of aquatic arthropods. Fossils of Hughmilleria have been discovered in deposits of the Silurian age in China and the United States. Classified as part of the basal family Hughmilleriidae, the genus contains three species, H. shawangunk from the eastern United States, H. socialis from Pittsford, New York, and H. wangi from Hunan, China. The genus is named in honor of the Scottish geologist Hugh Miller.

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

Bassipterus is a genus of eurypterid, an extinct group of aquatic arthropods. Bassipterus is classified as part of the family Adelophthalmidae, the only clade within the derived ("advanced") Adelophthalmoidea superfamily of eurypterids. Fossils of the single and type species, B. virgnicus, have been discovered in deposits of the Late Silurian age in West Virginia and Maryland, United States. The genus is named after Bass, where most of the fossils have been recovered.

<i>Pittsfordipterus</i> Genus of arthropods (fossil)

Pittsfordipterus is a genus of eurypterid, an extinct group of aquatic arthropods. Pittsfordipterus is classified as part of the family Adelophthalmidae, the only clade in the derived ("advanced") Adelophthalmoidea superfamily of eurypterids. Fossils of the single and type species, P. phelpsae, have been discovered in deposits of Silurian age in Pittsford, New York state. The genus is named after Pittsford, where the two only known specimens have been found.

Salteropterus is a genus of eurypterid, an extinct group of aquatic arthropods. Fossils of Salteropterus have been discovered in deposits of Late Silurian age in Britain. Classified as part of the family Slimonidae, the genus contains one known valid species, S. abbreviatus, which is known from fossils discovered in Herefordshire, England, and a dubious species, S. longilabium, with fossils discovered in Leintwardine, also in Herefordshire. The generic name honours John William Salter, who originally described S. abbreviatus as a species of Eurypterus in 1859.

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

Erettopterus is a genus of large predatory eurypterid, an extinct group of aquatic arthropods. Fossils of Erettopterus have been discovered in deposits ranging from Early Silurian to the Early Devonian, and have been referred to several different species. Fossils have been recovered from two continents; Europe and North America. The genus name is composed by the Ancient Greek words ἐρέττω (eréttō), which means "rower", and πτερόν (pterón), which means "wing", and therefore, "rower wing".

<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">Pterygotidae</span> Extinct family of eurypterids

Pterygotidae is a family of eurypterids, an extinct group of aquatic arthropods. They were members of the superfamily Pterygotioidea. Pterygotids were the largest known arthropods to have ever lived with some members of the family, such as Jaekelopterus and Acutiramus, exceeding 2 metres (6.6 ft) in length. Their fossilized remains have been recovered in deposits ranging in age from 428 to 372 million years old.

<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">Waeringopteridae</span> Extinct family of arthropods

Waeringopteridae is a family of eurypterids, an extinct group of aquatic arthropods. The Waeringopteridae is the only family classified as part of the superfamily Waeringopteroidea, which in turn is classified within the infraorder Diploperculata in the suborder Eurypterina. The earliest known member of the group, Orcanopterus, has been recovered from deposits of Katian age and the latest known surviving member, Grossopterus, has been recovered from deposits of Siegenian age. The name Waeringopteridae is derived from the type genus Waeringopterus, which is named in honor of eurypterid researcher Erik N. Kjellesvig-Waering.

<span class="mw-page-title-main">Adelophthalmidae</span> Family of eurypterids

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">Hughmilleriidae</span> Extinct family of eurypterids

Hughmilleriidae is a family of eurypterids, an extinct group of aquatic arthropods. The hughmilleriids were the most basal members of the superfamily Pterygotioidea, in contrast with the more derived families Pterygotidae and Slimonidae. Despite their classification as pterygotioids, the hughmilleriids possessed several characteristics shared with other eurypterid groups, such as the lanceolate telson.

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

Herefordopterus is a genus of eurypterid, an extinct group of aquatic arthropods. Herefordopterus is classified as part of the family Hughmilleriidae, a basal family in the highly derived Pterygotioidea superfamily of eurypterids. Fossils of the single and type species, H. banksii, have been discovered in deposits of Silurian age in Herefordshire and Shropshire, England. The genus is named after Herefordshire, where most of the Herefordopterus fossils have been found. The specific epithet honors Richard Banks, who found several well-preserved specimens, including the first Herefordopterus fossils.

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

Eysyslopterus is a genus of eurypterid, an extinct group of aquatic arthropods. Eysyslopterus is classified as part of the family Adelophthalmidae, the only clade within the derived ("advanced") Adelophthalmoidea superfamily of eurypterids. One fossil of the single and type species, E. patteni, has been discovered in deposits of the Late Silurian period in Saaremaa, Estonia. The genus is named after Eysysla, the Viking name for Saaremaa, and opterus, a traditional suffix for the eurypterid genera, meaning "wing". The species name honors William Patten, an American biologist and zoologist who discovered the only known fossil of Eysyslopterus.

<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. 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.
  2. 1 2 3 4 5 6 7 8 9 10 11 Erik Tetlie, O.; Poschmann, Markus (2008-06-01). "Phylogeny and palaeoecology of the Adelophthalmoidea (Arthropoda; Chelicerata; Eurypterida)". Journal of Systematic Palaeontology. 6 (2): 237–249. doi:10.1017/S1477201907002416. S2CID   59488956.
  3. 1 2 3 4 5 6 7 8 Kjellesvig-Waering, Erik N. (1961). "The Silurian Eurypterida of the Welsh Borderland". Journal of Paleontology. 35 (4): 789–835. JSTOR   1301214.
  4. 1 2 3 4 Tetlie, O. Erik; van Roy, P. (2006). "A reappraisal of Eurypterus dumonti Stainier, 1917 and its position within the Adelophthalmidae Tollerton, 1989" (PDF). Bulletin de l'Institut Royal des Sciences Naturelles de Belgique. 76: 79–90.
  5. ↑ O. Erik Tetlie; Paul A. Selden; Dong Ren (2007). "A new Silurian eurypterid (Arthropoda: Chelicerata) from China". Palaeontology. 50 (3): 619–625. doi:10.1111/j.1475-4983.2007.00651.x. hdl: 1808/8354 . S2CID   56066870.
  6. ↑ Clarke, J. K., Ruedemann R. (1912) "The Eurypterida of New York"
  7. 1 2 3 Tetlie, O. Erik (2004). Eurypterid phylogeny with remarks on the origin of arachnids (PhD). University of Bristol. pp. 1–344. Archived from the original on 2021-07-30. Retrieved 2018-09-06.
  8. ↑ Pirozhnikov, L. P. (1957). "Remains of Gigantostraca from the series of Matakara (Devonian of the North Minusinsk Depression)". Vsesojuzuoe Paleontologiceskoe Obchestvo Ezegodnik. 16: 207–213. ISSN   0201-9280. OCLC   229469975.
  9. 1 2 Kjellesvig-Waering, Erik N.; Leutze, Willard P. (1966). "Eurypterids from the Silurian of West Virginia". Journal of Paleontology. 40 (5): 1109–1122. JSTOR   1301985.
  10. 1 2 Shpinev, E. S. (2012). "On some eurypterids (Eurypterida, Chelicerata) from the Devonian of South Siberia". Paleontological Journal. 46 (4): 370–377. doi:10.1134/S0031030112040119. S2CID   128903698.
  11. ↑ Meaning of nanus, nani. latin-dictionary.net
  12. 1 2 Kjellesvig-Waering, Erik N. (1964). "Eurypterida: Notes on the Subgenus Hughmilleria (Nanahughmilleria) from the Silurian of New York". Journal of Paleontology. 38 (2): 410–412. JSTOR   1301566.
  13. ↑ Salter, John W. (1856). On some new Crustacea from the uppermost Silurian Rocks. Vol. 12. pp. 26–34.{{cite book}}: |work= ignored (help)
  14. 1 2 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.
  15. ↑ V. P. Tollerton (2003). "Summary of a revision of New York State Ordovician eurypterids: implications for eurypterid palaeoecology, diversity and evolution". Transactions of the Royal Society of Edinburgh: Earth Sciences . 94 (3): 235–242. doi:10.1017/S026359330000064X. S2CID   83873103.
  16. ↑ Tetlie, O. Erik (2007). "Distribution and dispersal history of Eurypterida (Chelicerata)" (PDF). Palaeogeography, Palaeoclimatology, Palaeoecology . 252 (3–4): 557–574. doi:10.1016/j.palaeo.2007.05.011. Archived from the original (PDF) on 2011-07-18.
  17. ↑ Jarzembowski, E. A. (2010). Fossil Arthropods of Great Britain. Vol. 35. Joint Nature Conservation Committee. p. 294. ISBN   978-1-86107-486-7. ISSN   0965-9994.{{cite book}}: |journal= ignored (help)
  18. ↑ "Nanahughmilleria norvegica-Ostracoderm Comm. at Rudstangen, Ringerike Dist.: Rootsikula, Norway". fossilworks.org. Retrieved 11 August 2018.
  19. ↑ "Eurypterid-Associated Biota of the Shunet Fm. at Khakassia near Lake Shunet: Lochkovian - Eifelian, Russian Federation". fossilworks.org. Retrieved 11 August 2018.
  20. ↑ "Eurypterid-Associated Biota of the Temeside Shale, Ludlow and Perton, England: Pridoli, United Kingdom". fossilworks.org. Retrieved 12 August 2018.
  21. ↑ "Delaware Water Gap Eurypterids (Silurian of the United States)". fossilworks.org. Retrieved 12 August 2018.
  22. ↑ Størmer, Leif (1935). "Dictyocaris, Salter, a large crustacean from the Upper Silurian and Downtonian" (PDF). Extract Norsk Geol. Tisskr. 15: 267–298.
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