Adelophthalmus - Knowledge

6018: 5287: 5275: 3730: 4626: 4638: 4469: 4460: 6459: 6379: 140: 9166: 2990: 3960: 3323: 1040: 3057: 1154: 9469: 115: 6365:, ventral vascular structures of the eurypterids, acted indeed as active respiratory structures during air breathing as previously suggested. This and the evidence of land incursions made by stylonurines implies that eurypterids could stay out of the water for prolongated periods. This does not change the fact that they were predominantly aquatic creatures, just as their swimming paddles (which 5946:. Van Oyen's synonymizations were based on ratios of the carapace alone, ignoring other important phylogenetic features as well as possible taphonomic effects (defects produced during fossilization) on the fossils. Subsequent research has proven the validity of some species, now defined based on clear and distinguishing characteristics, including 5382:, including the presence of an anterior triangle on the carapace (the function of which is uncertain), a central circular area of the carapace being raised, the eyes being further away from the margin of the carapace than from the ocelli, an oval metastoma, a long telson and the presence of epimera on the preabdomen. 1064:(actively swimming) eurypterids with prominent cuticle sculptures (ornamentation consisting of small, minute, scales across their backs). These scales are perhaps the most distinguishing feature of the group, though similar scales have been reported in other eurypterid groups, most notably the pterygotids, as well. 6212:

in many ways represented the last of its kind, being the final eurypterid to possess swimming appendages, it did not exist in diverse eurypterid faunas such as the ones observed with genera during the Silurian or early Devonian. Instead, the brackish of fresh water environments typically inhabited by

5321:

made it difficult to assess if the legs truly were non-spiniferous. A new genus for non-spiniferous species could be phylogenetically supported, but transferring the new genus to the Slimonidae based on the loss of a feature which seems to have been lost independently in the two groups is not in line

6431:

The juveniles appear to have developed and lived in somewhat different conditions than the adults. In beds were juveniles are more common, insect fossils are more common as well, indicating a lack of adults that were capable of devouring them, and the presence of smaller plant fossils suggest a less

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also possessed) indicate. Furthermore, it is possible that being out of the water would have been ineffective for them during their alimentation, limiting the time they stayed there. However, they may have moved from pool to pool to breed in safer locations, supported by the usual separation between

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as a whole mainly lived in environments near coastal habitats, with a preference for habitats with reduced salinity such as river deltas, estuaries or lagoons. Marine influences are often recorded from these habitats and the deposits carrying adelophthalmoid fossils, but typical marine index fossils

6249:

were small, it is most likely that it fed on small organisms, possibly in part the ostracods and branchiopods known from associated fossils. There is a noticeable lack of insects in the fossil beds with dense plant fossils, where they should be more common, and a surprising abundance in fossil beds

6008:

were described by authors who were not eurypterid specialists (since eurypterid researchers mostly concentrated their efforts on the more diverse pre-Carboniferous eurypterids) and most descriptions lack in comparisons with previously described species of the genus. As such, the differences between

4731:

being the most derived member of its family is confirmed by its swimming appendages being the thinnest of all included genera and by its eyes being the closest to the center of the carapace. In adelophthalmoids, eyes appear to get closer to the center of the carapace with every more derived genus,

6446:

live in different environments and regions than the adults. The advantage of this form of segregation is not only to allow younger individuals to live in conditions more stable from a salinity standpoint, but also to keep juveniles safe from situations in which substantial amounts of marine water

5888:

valid, group, but that it likely suffers from an under-splitting at the genus level and over-splitting at the species level. It is possible that the large amount of species form two or more distinct clades that could be split into different genera. Though most of the species included in the genus

3524:

based on two incomplete fossils and few other small fragments from Elmo in Kansas. The first specimen preserves the carapace and the first four tergites of the preabdomen, while the second preserves five preabdominal and three postabdominal tergites; this specimen represents twice the size of the

1233:

The status of the 35 names (out of which two are synonyms) listed below follow a 2018 survey by German paleontologists Jason A. Dunlop and Denise Jekel and British paleontologist David Penney and size- and temporal ranges follow a 2009 study by American paleontologists James Lamsdell and Simon J.

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Though habitats of this kind were many, widespread and ecologically stable for a time in the early Permian, they would turn out to be delicate. A changing climate during the Permian altered depositional and vegetation patterns across the northern hemisphere, which drastically affected previously

6128:

environment) together with fossils of freshwater bivalves and terrestrial organisms. It is possible that these freshwater "conquests" are related to the diversification of the genus itself and the appearance of several new species during the Carboniferous, rather than reflecting a shift in the

6289:(external gills arranged like the pages of a book), although they were probably five, as in xiphosurans. These are oriented horizontally and all of them but the ones from the sixth segment are fragmentary. There, they are oval in shape, attached near the midline of the body and consist of six 3032:

Since the preserved carapace had no indication of there ever having been any eyes present, Jordan and von Meyer assumed that the animal would have been completely eyeless in life, with the original description of the fossil citing several cases in which eyeless forms occur in arthropod groups

6428:, but smaller individuals (juveniles) are found in fossil beds containing less organic material and mostly smaller plant fragments. The large plant fragments of the adult habitat were deposited in quiet conditions, likely through leaves dropping into enclosed lagoons or standing ponds. 6436:

would thus be variable, while juveniles could live in fresher and less variable environments further away from the shoreline. It is possible that the adults mated in the streams that fed the ponds, and then returned to live in the ponds because of a richer food supply being present.

6172:

is nowhere to be found, which indicates that a shift to an environment further away from the ocean caused the extinction of these populations, which indicates that several species needed some form of connection to habitats of marginally marine nature, even if they did not live in

6265:. It is however likely that various predatory fish, amphibians and early reptiles known to have been present at the time would have preyed upon the small eurypterids. Both fish and amphibians are known from similar environments of the same age in the nearby Manzanita Mountains. 3287:, naming the species in his honor. The only known specimen is composed of six body segments and Woodward noted that naming the species may have been slightly premature. He noted that the specimen possessed markings and spikes running alongside the abdomen in a similar way to 5869:

in terms of all the species it is recognized as containing can thus not be fully confidently stated to be monophyletic, more fragmentary species need to be redescribed and more phylogenetic characters need to be confidently established before the status of the genus can be

2011:

can be distinguished from most other species by its first segment being narrower relative to the other segments of the mesosoma. The characteristic abdominal spikes were present in the last segment of the mesosoma and all the metasomal segments. Compared to other species,

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and featuring descriptions of several other arthropod taxa. The fossil was immediately recognized by Jordan as that of a eurypterid, with both the overall shape and form and the individual parts (particularly the head and the appendages) being very similar to those of

4580:

appears to have lived in environments of brackish to fresh water on a deltaic plain adjacent to a coastal plain. Climate conditions favorable for the spread and maintenance of such environments were optimal during the Late Carboniferous and Early Permian, with

3028:

which had been described in the United States in 1825, 29 years earlier. Among the differences noted between the specimens were the smaller size and later age of the Saarbrücken fossil and what Jordan and von Meyer perceived to be a complete lack of eyes.

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in Ukraine. A new expedition in 2012 carried out by Russian paleontologist Evgeniy S. Shpinev and others in the respectively Russian and Ukrainian localities of Kakichev and Lomuvatka brought a number of well-preserved, presumably juvenile, fossils of

6416:, including several adults and juveniles, allowed researchers to determine different habitat preferences for different age groups. Larger individuals (adults) are found associated with large plant fragments, including branches of 3891:

of Khakassia (hence the name) in 2014 by Filimonov, it represents the biggest species of the genus. The holotype, PM TGU 168/108, is composed of parts of the metasoma and a complete telson, with several other known paratypes. As

2578:

in possessing a median furrow (raised structure through the center of the carapace) on its prosoma and in the corners of the carapace not being expanded. Its first tergite has an almost identical morphology as that possessed by

2818:. The species can be differentiated from others in the genus by its relatively broad carapace, a short podomere 7 on the swimming legs and rows of tubercles along the posterior edges of the carapace and opisthosomal segments. 6343:

and represent a terrestrial adaptation to breathe air. They prevent the lamellae from sticking together and eliminating the space between them, which would suffocate the organism. Therefore, the presence of trabeculae in

3685:

of New Mexico. The large amount of specimens recovered, representing individuals at various stages of development and ontogeny, allowed detailed studies to be performed on the ontogeny and intraspecific variation within

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Lamsdell, James C.; Simonetto, Luca; Selden, Paul A. (2013). "First Eurypterid from Italy: A new species of Adelophthalmus (Chelicerata: Eurypterida) from the Upper Carboniferous of the Carnic Alps (Friuli, NE Italy)".

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was described in 2006 based on a fossil specimens (including the holotype, a prosoma, "head", with the specimen number PIN no. 5109/4) collected by the Krasnoyarsk Geological Expedition near Sakhapta, a village in the

1958:. It differs from all these species in a narrower mesosoma and in a wider metasoma. It had undeveloped epimera in the seventh, eleventh and twelfth segments (being in these last two segments flattened and leaf-like). 6055:

this is seen as particularly likely as it is represented by a single specimen that is also the only eurypterid specimen collected from the formation in which it was found, the Gogo Formation of Western Australia.

5392:

was recovered as more basal than other species, which fits with it also being the earliest known species in the fossil record, mainly due to the broad swimming appendage being similar to the broad appendages of

4180: 2661:

had in its second to fifth appendages a pair of ventrodistal spines on each podomere. Furthermore, it had epimera in its postabdomen and the first segment did not have any lateral reduction. This suggests that

4217:

Already widespread and represented around all major landmasses in the Late Devonian, the amalgamation of Pangaea into a global supercontinent during the Carboniferous and Permian would allow the able swimmer

6184:, from the Late Moscovian, the later Carboniferous and the Early Permian, show a larger presence in habitats with marine influence, particularly habitats of tidally influence estuarine environments. Despite 4732:

and even though eye position may reflect lifestyles and inhabited environments, they are also assumed to (particularly in this case, with a clear progression) include phylogenetically important information.

4166:

was relatively unscathed, adapting new strategies (such as sweep-feeding) to avoid competition, and came to diversify once more in the Carboniferous, the Eurypterina was rendered almost completely extinct,

4560:, despite being separated by a timespan of more than a hundred million years. The similarities are likely due to a generalized, and not a specialized, ecological niche. This morphological conservatism in 3837:"doubtful"), both based on fossils originally collected by Russian geologist Yuriy Fedorovich Pogonya-Stefanovich in 1960 in deposits 3 km southeast of the village of Kamyshta (which lent its name to 6370:

adult and juvenile eurypterids in the fossil record and by the possession of spermatophores, which could have allowed eurypterids to store sperm for months to give them time to seek a secure environment.

4564:

suggests that the genus became bradytelic, evolving at a slower rate than the standard rate among eurypterids. Typically, bradytelic organisms have a broad geographical spread, something that was seen in

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under a different species name based on the original collector of the fossil (Dr. Palisa) and without any designation of it representing a type specimen. Pruvost was also honored through the naming of

962:

had begun early, with representatives found in both Siberia and Australia during the Devonian, but it first gained its almost cosmopolitan distribution following the amalgamation of the supercontinent

1090:

at just 4 cm (1.6 in) in length. The genus as a whole does not appear to have fluctuated much in size over the course of its long evolutionary history, with "large" species occurring in the

3425:

being fragmented, owing to careless usage of hammers and diamond bores during excavation, the fossil could nevertheless be studied in detail and compared to known eurypterid species. As Stainier

1015:

is the most taxonomically diverse of all eurypterid genera, containing 33 species considered valid. This large amount of species, many named long ago, have prompted some researchers to designate

3045:("grainy" or "full of grains"), referring to the state of the fossil preservation having given some of the fossils a grainy texture. The type specimen, to this day the only specimen referred to 3365:. Woodward described very large fossil specimens, the carapace alone measuring 21 cm (8.3 in) and the seven associated body segments measuring an additional 25 cm (9.8) together. 1824:

had relatively broad proportions. With the only known specimen lacking eyes and appendages, its status as diagnostic is somewhat questionable. It is possible that the large abdominal spikes of

6412:

was a moderately elevated region with less dense vegetation and better drainage than the swamplands that occupied much of the rest of the United States. The discovery of a large assemblage of

6432:

prolific vegetation cover, the juvenile environment possibly having been lower areas on the delta plain between the ponds. Periodically, storms would drive marine water into the ponds, where

3796:

to be described from Russia and the first ever Carboniferous eurypterid known from the country. It is also one of few Carboniferous eurypterids found within the territory of the former

6009:

species are often trivial, perhaps partly resulting from that the first overview paper on the taxon was published only in 1948, at which point 26 species had already been described.

5989:

as of 2020, the largest amount of any eurypterid), is geographically widespread, named a long time ago (1854) and the nominate form of a higher taxon (lending its name to the family

4704:), 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. 3987:

in the Late Silurian, being a part of a rapid diversification of swimming eurypterids (suborder Eurypterina) throughout the Silurian. Baltica would later collide with the continents

3654:

to potentially represent a distinct genus, citing that scorpions with similar dorsal anatomies can be quite different ventrally and that the same could be true for the Carboniferous

6599: 6188:

spreading to fully freshwater environments, their conquests of these environments was apparently not as successful as that of other similar groups, for instance some Carboniferous

7934:

Kues, Barry S.; Kietzke, Kenneth K. (1981). "A Large Assemblage of a New Eurypterid from the Red Tanks Member, Madera Formation (Late Pennsylvanian-Early Permian) of New Mexico".

4203:

experienced a rapid diversification through the Carboniferous, with 23 of its 33 species having been described from the Carboniferous alone, and reached its peak diversity in the

6447:

decimated the populations in the ponds by altering the living conditions too much. In such a situation, younger populations could after some time recolonize the old habitats.

6440:

Age-based segregation of this kind between juveniles and adults of the same population is relatively normal in arthropods, for instance, juveniles of the related and modern

2173:

and has several features that are not consistent with the genus. These include a very wide carapace, very large eyes and what appears to be a median ridge on its carapace.

3849:. Despite how poorly preserved these fossils are, several features (notably the parabolic carapace and the presence of spikes along the abdomen) place both species within 3646:

in studies during the middle twentieth century, notably that of Belgian paleontologist Fredrik Herman van Oyen (1956). Though most authors assign all described species to

4327:

discovered in France is also known from this time. The Late Carboniferous would see the appearance of several more species in various places around the world. During the

6261:

have been preserved in the Madera Formation are all part of the Red Tanks Member, which does not preserve any known organisms that would have been capable of preying on

6133:

seem to form a minority, with most species being confined to paralic or lowland basins in depositional environments with close connections to marginally marine habitats.

1031:(a group sharing a common ancestor) but might most appropriately be split into different genera along distinct clades formed within the current confines of the genus. 3888: 3792:

based on their scalelike ornamentation, the position of their eyes and the shape of the carapace shortly after their excavation. The species is the first species of

3555:, MB.A. 889, was collected in the Czech Republic in 1930 or 1931 and first mentioned in a manuscript by French Carboniferous worker Pierre Pruvost, who dubbed it " 1185:

was parabolic in shape, with a narrow marginal rim (edge). The carapace was held in place with the aid of a small and hinged triangular "locking" mechanism placed

3394:

based on fossils recovered in Nebraska, USA. The species was described alongside other fossils from the associated sediments, which helped reinforce the idea as

3846: 6308: 5325:

The cladogram below displays the results of a phylogenetic analysis conducted by O. Erik Tetlie and Markus Poschmann in 2008, featuring seven species of

4527:

is known to have lived in a freshwater environment, its fossil being found in association with fossils of land plants. The youngest described species is

4295:(although this species may have occurred as early as the Famennian stage, the last stage of the Devonian). The genus also spread to modern day Scotland ( 6245:

indicates that it was a good swimmer, though it is likely that it spent most of its time crawling in the mud. As the chelicerae (frontal appendages) of

9641: 4199:, existing in far greater number than the surviving members of the Stylonurina, both in terms of the number of individuals and the number of species. 3946:, and after their study it was confirmed that even if they had a mostly aquatic lifestyle, the eurypterids could venture on to land for long periods. 3100:, but ignored the rules of taxonomical priority and used his younger name due to it being based on material that he considered to be better preserved. 993:, the apparent eyelessness of the type specimen is treated by modern researchers as a preservational artifact, and not a feature that any species of 3084:

would have had in life, this issue was not resolved immediately which made the naming of subsequently discovered species confusing and problematic.

5329:

and excluding other species on the grounds that they were too incompletely known. All characters were treated as unordered and given equal weight.

6285:

nodule on the ventral side of the animal is split in a manner in which the branchial chamber (gill tract) is visible. This uncovers four pairs of

9532: 8533: 5967:

is an ongoing area of research, perhaps the most important question that remains unanswered is the exact relationship between the type species

4692:

The cladogram below presents the inferred phylogenetic positions of most of the genera included in the three most derived superfamilies of the

1705:

is incredibly poorly known, the only known specimen lacking the eyes, the appendages and even the abdominal spines otherwise always present in

8394:"A New Eurypterid (Chelicerata: Eurypterida) from the Upper Devonian Gogo Formation of Western Australia, With A Review of the Rhenopteridae" 1787:

having a broader carapace, larger eyes, a more slender thorax and the characteristic spikes running along its abdomen pointing backwards (in

8249:

Shpinev, Evgeniy S. (2012). "New species of the genus Adelophthalmus (Eurypterida, Chelicerata) found in the Middle Devonian of Khakassia".

8165:"The Eurypterid Adelophthalmus Sievertsi (chelicerata: Eurypterida) from the Lower Devonian (emsian) Klerf Formation of Willwerath, Germany" 6017: 9656: 6620: 8503:

Tetlie, O. Erik; Poschmann, Markus (2008). "Phylogeny and palaeoecology of the Adelophthalmoidea (Arthropoda; Chelicerata; Eurypterida)".

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to the north, which resulted in the basin being located 1,300 km (810 miles) further away from the ocean. In these younger deposits,

1443:, though was noted as being significantly different in it possessing "comb organs" by British paleontologist Charles D. Waterston in 1958. 989:(head plate) completely lacking any indication of eyes. Though this has caused much subsequent confusion, including the naming of several 9671: 9636: 6348:

indicates that eurypterids were able breathe in terrestrial environments with their respiratory organs unlike xiphosurans or other basal

6293:. The number of lamellae in the other anterior segments is thought to have been higher, as indicated by some fragments and a specimen of 3681:

was described by American paleontologists Barry S. Kues and Kenneth K. Kietzke in 1981 based on 150 fossil specimens recovered from the

3559:", but he did not formally describe the specimen or taxon. Pruvost had previous experience with the genus, having described the species 3449:), he classified the new Belgian eurypterid in that genus as well. He did note that the new species was very similar to species such as 5306:

are poorly known, owing to its long history and the large amount of species assigned to the genus, many based on fragmentary remains.

5286: 5274: 3729: 6077:, which are recovered in non-marine deposits such as in environments that were once brackish or estuarine habitats. The evolution of 2901:. The only known specimen consists of six body segments. These segments possess markings and spikes alongside the abdomen similar to 1537:

specimens of the same size class. The same ratio of the length of the metasoma to length of the mesosoma was somewhat larger than in

8220:

Shpinev, Evgeniy S. (2006). "A new species of Adelophthalmus (Eurypterida) from the lower carboniferous of the Krasnoyarsk Region".

9519: 8278:

Shpinev, Evgeniy S. (2014). "New data on eurypterids (Eurypterida, Chelicerata) of the Upper Carboniferous of the Donets Basin".

7726: 3413:. The type specimen, a relatively complete fossil measuring just 3.3 centimetres (1.3 in) in length, was discovered through 8126:

Peach, Ben N. (1882). "Further Researches among the Crustacea and Arachnida of the Carboniferous Rocks of the Scottish Border".

7743: 6038:(fossils that indicate a marine environment and ecosystem) are not found associated with the eurypterid remains. The occasional 9621: 6277:

imaging, researchers have been able to observe in detail the structure of the respiratory organs of the only known specimen of

3498: 5899:

in its supposed trapezoid carapace (a feature now known to be incorrect and based on an incorrect illustration) and the large

9651: 9596: 9245: 9235: 8757: 8374: 6352:. Its trabeculae are also highly similar to those of arachnids, especially that of a specimen of an indeterminate species of 5889:

appear to form a monophyletic group, some species have been suggested to represent species of other recognized genera, with

2108:

but possessed indentations around the edges of its exoskeleton, a feature that separates it from all other known species of

3662:

of this nature would be problematic due to its classification depending on the preservational state of any given specimen.

8421:"A redescription of the Late Carboniferous eurypterids Adelophthalmus granosus von Meyer, 1853 and A. zadrai Přibyl, 1952" 917:

until its extinction during the Permian, after which the few surviving eurypterids were all walking forms of the suborder

905:, which makes it the longest lived of all known eurypterid genera, with a total temporal range of over 120 million years. 9661: 9626: 9611: 3088:, named in 1855 from Carboniferous-age deposits in Germany, shows definite eyes. The descriptor, Austrian paleontologist 1310:

by the lack of differentiation between the first three pairs and the last pair of the endognathites being less distinct.

1083:, reached a maximum length of approximately 32 cm (12.6 in). Many species were smaller, the smallest being the 4380:

stage (from 315.2 to 307 million years ago) saw the appearance of several new species, including the two German species

3033:

otherwise possessing eyes (such as in crustaceans and trilobites). This apparent eyelessness prompted the choice of name

3009:

to be discovered was excavated in 1851 by German paleontologist Hermann Jordan in a railway shaft at Jägersfreude, near

9666: 9631: 9197: 7907: 7830: 3915:, in France. Its only known specimen, GLAHM A23113, is a nearly complete body only lacking the telson and preserved in 1398:, differing only in being proportionally shorter and not possessing indentation around the edges of the exoskeleton as 7840:

Dunbar, Carl O. (1924). "Kansas Permian insects, Part 1, The geologic occurrence and the environment of the insects".

9212: 4158:. Of the 16 eurypterid families that had been alive at the beginning of the Devonian, only three persisted into the 3532:

was described by American paleontologist Carl E. Decker in 1938 based on Permian-age fossils in Oklahoma. Since the

3210:

would for a long time erroneously be considered to represent the fossil remains of a scorpion and not an eurypterid.

3080:

Though modern researchers tend to treat the assumed eyelessness as a preservational artifact and not a feature that

8099: 5914:

was suggested by Fredrik Herman van Oyen in 1956 to possibly represent a senior synonym of many species, including

9601: 9456: 9240: 9182: 8456:"A reappraisal of Eurypterus dumonti Stainier, 1917 and its position within the Adelophthalmidae Tollerton, 1989" 6477: 7918: 5317:

family of eurypterids, citing their lack of spines, however noted that the then presently available material of

4054:

from outside Europe, fossils of the three having been recovered from Khakassia in Russia. By the Late Devonian,

3757:(described earlier in 2004 based on the singular specimen BMNH In 60174 from the Late Devonian of Australia) to 9606: 9230: 9220: 9174: 7957:"Cope's Rule and Romer's theory: patterns of diversity and gigantism in eurypterids and Palaeozoic vertebrates" 4147: 3361:

from America, finding the spikes along the abdomen very similar, though noted that they were less prominent in

3050: 4428:

from Mechelen-sur-Meuse, Belgium. The very latest Carboniferous and early Permian would see the appearance of

9616: 9192: 9187: 3907:

In 2020, Lamsdell, Victoria E. McCoy, Opal A. Perron-Felle and Melanie J. Hopkins described a new species of

2855:. A poorly known species based on a single fossil consisting of a series of fragmentary segments. Similar to 1225:

from other adelophthalmid eurypterids is its elongated body and the spurs present on its abdominal segments.

6152:

in age) are from a time in which the basin was either part of, or at the very least connected to, a western

5910:

Many of the more fragmentary species could very well be synonyms of more well known species. In particular,

4711:

A close relationship between the three groups is confirmed partly due to basal members of all three groups,

3868:) was collected in the gravel bank of a small creek near the greater Bombaso creek, north of the village of 9646: 9591: 9225: 9202: 4491:

includes five species, all of which were confined to the Early Permian. The first stage of the period, the

3224: 139: 7999: 7760: 3761:

This species had previously not been assigned to the genus despite clear similarities to other species of

3228: 1541:, while the ratio of the length of the prosoma to length of the mesosoma was smaller than in the latter. 127: 3466: 9586: 3272: 6404:

and associated organisms lived in bodies of brackish to fresh water in what is assumed to have been a

1533:

in the proportions of the body. Its carapace had a length/width ratio similar to the average value of

8858: 8750: 7886: 6472: 6290: 6149: 6117: 4377: 4323:

is particularly notable as it represents the hitherto only known Carboniferous eurypterid in Russia.

3426: 2891: 2698: 2615: 2465: 2330: 2294: 2088: 1864: 1815: 1769: 1334: 1003:

was a genus of comparatively small eurypterids, with species ranging in size from 4 cm (1.6 in,

949: 6097:

are found in sections that are considerably more marginally marine than those sections inhabited by

6081:

saw a shift from brackish environments to habitats dominated by fresh water. In habitats where both

1221:(the posteriormost segment, here in the shape of a spike). The feature that primarily distinguishes 4625: 4143:, which would mean that the range of the genus included water around all then existing continents. 3916: 3089: 1783:, similar in overall shape and proportions and in the pattern of the ornamentation. They differ in 7897: 8207:

Reuss, Adolf E. (1855). "Über eine neue Krusterspecies aus der Böhmischen Steinkohlenformation".

3864:. The specimen (specimen number MFSNgp 31681, housed at the Museo Friulano di Storia Naturale in 3575:, at a point in time when the type specimen was seemingly lost. The specimen was rediscovered in 3248: 3139: 8581:

Waterston, Charles D. (1968). "Further Observations on the Scottish Carboniferous Eurypterids".

6299:

that had 45 lamellae in each of its four pairs of book gills from the second to fifth segments.

6254:

fed on insects that had fallen into the water, hindering these from being preserved as fossils.

6071:

environments inhabited during the Silurian. The earliest adelophthalmoids, such as the Devonian

4027:

lived in near-shore environments, typically a varied and unstable habitat, which indicates that

3788:. The fossils, from the Tournaisian Solomennyi Stan Formation, could confidently be assigned to 3721:

having larger eyes, a wider carapace and what could possible by a median ridge on the carapace.

9563: 9487: 9165: 7820: 3473: 3391: 3115: 9537: 7888:

Fauna Saraepontana Fossilis. Die fossilien Thiere aus der Steinkohlenformation von Saarbrücken

6316:

underwent a taphonomic deformation and that they were originally vertically-oriented as well.

3938:, threw stones that transformed into babies to repopulate the world. The good preservation of 3587:

by Norwegian paleontologist Erik N. Kjellesvig-Waering in 1948 based on fossils discovered in

3185:

was erected to include some fossils from the Carboniferous of Scotland, including the species

2266:

but has a narrower carapace, smaller eyes and a wider thorax. The spikes along the abdomen of

9558: 9550: 6274: 6001:", a taxon existing for the sole purpose of classifying organisms that do not fit elsewhere. 3842: 3422: 941: 8046:

Rivista Italiana di Paleontologia e Stratigrafia (Research in Paleontology and Stratigraphy)

7998:

Lamsdell, James C.; McCoy, Victoria E.; Perron-Feller, Opal A.; Hopkins, Melanie J. (2020).

913:

suborder of eurypterids and consisted the only known genus of swimming eurypterids from the

9472: 8743: 8664: 8623: 8534:"The ventral anatomy of the Upper Carboniferous eurypterid Anthraconectes Meek and Worthen" 8474:

Tetlie, O. Erik (2007). "Distribution and dispersal history of Eurypterida (Chelicerata)".

7870: 7849: 7774: 4637: 4020: 3749:

by Norwegian paleontologist Leif Størmer in 1969 based on fossil remains from the Devonian

3672:

by Spanish paleontologist Bermudo Meléndez in 1971 based on fossils from d'Ablana in Spain.

3409:, Carboniferous in age, was described by Belgian paleontologist Xavier Stainier in 1915 as 2928: 2872: 2834: 2783: 2721: 2687: 2641: 2596: 2557: 2488: 2454: 2417: 2367: 2319: 2283: 2236: 2186: 2135: 2069: 1985: 1918: 1889: 1853: 1804: 1758: 1671: 1631: 1589: 1554: 1500: 1458: 1415: 1361: 1323: 1273: 8700: 2810:

is, despite its early age, most similar to late Carboniferous and Permian species such as

1193:

were located between, or slightly behind (depending on the species), the larger eyes. The

952:(worldwide) distribution, one of few eurypterid genera to achieve one besides potentially 8: 6464: 6145: 4370: 3912: 3777: 3588: 3177:

in regards to specimens described after the type specimen in the belief that the type of

1122:

at 18 cm, 7 in). Most of the smaller species are known from the Carboniferous, when

8668: 8627: 7853: 7778: 6196:

family, that occurred in freshwater lakes and basins that completely lacked eurypterids.

4179: 3876:

and seven opisthosomal segments on a large block of sandstone. The name of the species,

3609:. The exact identification of these fossils is not possible, but they are identified as 8680: 8639: 8598: 8569: 8520: 8361: 8328: 8295: 8266: 8237: 8151: 8086: 8031: 7981: 7956: 7943: 7790: 6164:

in the south during the Pennsylvanian and Early Permian, drainage became routed to the

6157: 6068: 4204: 3943: 3927: 3781: 3350: 3119: 3069: 1028: 697: 134: 8455: 8357: 7727:"Eurypterid Beds of Nebraska with Notice of a New Species, "Eurypterus Nebraskaensis"" 4214:

remained the only genus of eurypterine eurypterids until the extinction of the group.

3883:

In 2018, Shpinev and Russian researcher A. N. Filimonov described a new species named

3421:, northern Belgium. Though the fossil had been slightly damaged, including the entire 2404:

is also known for its unusually long telson and generally slender and thin body plan.

9545: 9061: 8994: 8986: 8724: 8712: 8684: 8643: 8602: 8573: 8491: 8442: 8410: 8393: 8380: 8365: 8299: 8191: 8181: 8164: 8155: 8143: 8090: 8035: 8023: 7986: 7903: 7826: 7794: 7765: 6408:. The lack of large coal beds suggests that the fossil localities which have yielded 6306:

s book gills, however, were vertically oriented. This and a fossil of the xiphosuran

6165: 6034: 5998: 5994: 4846: 4753: 4701: 4656: 4071: 3263: 3165:

was coined by German paleontologist Friedrich Goldenberg (who also named the species

3018: 3001:

in 1854. The apparently eyeless carapace can be seen in the bottom-left illustration.

2998: 1210: 1020: 8524: 8332: 8270: 8241: 7744:"A New Genus of Characeae and New Merostomata from the Coal Measures of Nova Scotia" 3596:

1933 saw Ukrainian paleontologist Boris Isidorovich Chernyshev describe the species

9401: 9115: 9107: 9097: 9089: 9069: 9040: 8956: 8905: 8672: 8631: 8590: 8561: 8512: 8483: 8432: 8405: 8353: 8320: 8287: 8258: 8229: 8176: 8135: 8078: 8053: 8013: 7976: 7968: 7857: 7782: 6073: 5990: 5885: 5590: 5566: 5515: 5446: 5395: 5360: 5309:

American paleontologist Victor P. Tollerton suggested in 1989 that some species of

4965: 4941: 4908: 4679: 4667: 4661: 4652: 3919: 3682: 3521: 3017:("Of the crustaceans of the coal formation of Saarbrücken"), written by Jordan and 2533: 2497: 1173: 1050: 220: 207: 8192:"An arthropod (Merostome) ichnocoenosis from the Carboniferous of northwest Spain" 4613:) that occupied niches outside of these habitats continued to survive for a time, 4468: 4459: 2392:

are on the sternites which separates this species from all other known species of

9430: 9276: 9133: 9074: 9030: 8933: 8920: 8487: 8392:

Tetlie, O. Erik; Braddy, Simon J.; Butler, Piers D.; Briggs, Derek E. G. (2004).

8311:(Eurypterida, Chelicerata) from the Devonian of the South Minusinsk Depression". 8004: 7803: 7178: 7176: 7174: 7172: 7159: 7157: 7155: 6483: 6319:

The dorsal surface of each lamellae is covered by regularly spaced pillar-shaped

6161: 6042:

fossils found in obviously marine deposits, such as the Late Devonian Australian

5069: 4723: 4609: 4035: 3931: 3750: 3322: 990: 914: 7702: 7690: 7477: 4331:

stage (from 323.2 to 315.2 million years ago), two species appeared in Belgium,

4127:

is however represented by a single fragmentary specimen whose identification as

3765:

partly due to there previously not being any solid evidence for the presence of

3548:

by American geologist Carl Colton Branson, with the support of Decker, in 1959.

2348:, but the spikes running alongside the abdomen are noticeably less prominent in 9510: 9346: 9304: 9125: 9052: 9012: 9004: 8928: 8000:"Air Breathing in an Exceptionally Preserved 340-Million-Year-Old Sea Scorpion" 6383: 6354: 6295: 6060: 5975:, which could have major implications for the internal phylogeny of the genus. 5418: 5379: 5343: 5031: 4791: 4743: 4697: 4352: 4251: 4151: 4111: 4067: 4012: 4000: 3486: 3414: 3284: 898: 30: 8676: 8653:"Two New Species of Eurypterus from the Coal-Measures of Ilkeston, Derbyshire" 8635: 8594: 8583:

Earth and Environmental Science Transactions of the Royal Society of Edinburgh

8565: 8516: 8324: 8291: 8262: 8233: 8139: 8128:

Earth and Environmental Science Transactions of the Royal Society of Edinburgh

8082: 8071:

Earth and Environmental Science Transactions of the Royal Society of Edinburgh

8057: 8018: 7169: 7152: 6089:

are found, such as in Early Devonian fossil sites in Germany where fossils of

4131:

or even eurypterine at large is questionable, with it possibly representing a

3013:

in Germany. This specimen was described three years later in 1854 in the work

3010: 2997:, MB.A. 890, as illustrated in its original description by Hermann Jordan and 2211:

can be distinguished by its unusually wide prosoma (in other species, such as

9580: 9353: 9325: 9318: 9290: 9269: 9022: 8961: 8951: 8943: 8897: 8887: 8879: 8835: 8799: 8495: 8446: 8147: 7786: 5865:, as their character states could not be confidently taken into account, and 5467: 5370: 5182: 4860: 4685: 4292: 4227: 4159: 4155: 2252: 1840:

as in other species, but this feature may also simply be due to deformation.

967: 929: 902: 72: 34: 8209:

Denkschriften der Königlich-kaiserlichen Akademie der Wissenschaften in Wien

8110: 7861: 4617:, restricted to a rapidly disappearing type of environment, became extinct. 4388:, both from Saarbrücken. Further Moscovian-age species include a variety of 4222:

to gain an almost worldwide distribution, with Carboniferous-age fossils of

4191:

Following the extinction of all other swimming eurypterids in the Devonian,

9311: 9143: 9079: 9035: 8910: 8437: 8420: 8027: 7990: 7972: 6378: 6349: 6226: 6217:

such as the Early Permian Madera Formation in New Mexico (where fossils of

5895: 5881: 5432: 5354:

The results of the analysis showed that all the genera featured (including

5337: 5331: 5117: 5045: 4808: 4767: 4713: 4536: 4507:, Portugal and the continued survival of the Carboniferous Chinese species 4300: 4132: 3904:, it has been suggested that these three species could represent synonyms. 3810: 3797: 3613:

since there are no features showing the opposite. Another Belgian species,

2989: 2144: 250: 7523: 7521: 1071:

was, in comparison to larger apex predatory members of the group (such as

9408: 9385: 9283: 8977: 8870: 8808: 8790: 7455: 7453: 7142: 7140: 7138: 7136: 6488: 6405: 6332: 6193: 6125: 6064: 5498: 5347:, was included in the analysis as an outgroup to polarise the characters. 4891: 4693: 4673: 4597:

as well as brackish and fresh water habitats. As their habitat vanished,

4594: 4441: 4312: 4304: 4283:

The Early Carboniferous saw the appearance of a few new species, notably

4163: 3983:

The adelophthalmids likely first appeared in the waters of the continent

3741:

In 2004, the German paleontologist Markus Poschmann referred the species

2802: 2652: 1900: 1202: 918: 910: 181: 47: 8552:

Waterston, Charles D. (1958). "The Scottish Carboniferous Eurypterida".

8104:. Geological Survey of Illinois. Vol. 3: Geology and Palaeontology. 6059:

In general, post-Devonian eurypterids are rare and occur in habitats of

4519:(from 295 to 290.1 million years ago), which also saw the appearance of 4444:

of Italy, the first and hitherto only eurypterid known from the country.

3149:

type specimen in 1934, German paleontologist Paul Guthörl remarked that

3056: 1039: 114: 9524: 9374: 9360: 9339: 9332: 9297: 9138: 8826: 8817: 8766: 8384: 8376:

Treatise on Invertebrate Paleontology, Part P Arthropoda 2, Chelicerata

7947: 7518: 7217: 6495: 6320: 6153: 6113: 5314: 5165: 5141: 4585:

being widespread and numerous in these times. In most of the locations

4532: 4328: 4123:

represents the oldest known eurypterid hitherto discovered in Belgium.

4082: 4076: 3996: 3964: 3959: 3815: 3332: 3189:(designated as type, the type specimen consisting of only five tergites 3024: 2947: 2740: 1608: 1515: 1511: 1477: 1380: 1053: 954: 886: 840: 791: 765: 194: 92: 57: 7759:

Bicknell, Russell D. C.; Smith, Patrick M.; Poschmann, Markus (2020).

7645: 7596: 7450: 7133: 6723: 6721: 6719: 5903:

showing ornamentation similar to the one seen in the Hibbertopteridae.

4031:

was eurytopic (capable of surviving in a wide range of environments).

1153: 9451: 9435: 9425: 8784: 7680: 7678: 7676: 7674: 7672: 7465: 7123: 7121: 7119: 7117: 7115: 7113: 7111: 7109: 6717: 6715: 6713: 6711: 6709: 6707: 6705: 6703: 6701: 6699: 6424: 6382:

The same type of age-based segregation of individuals seen in modern

6336: 6324: 6286: 6282: 6238: 6234: 6189: 6129:

habitat preference of the genus as a whole. Indeed, these coal swamp

4603: 4516: 4344: 4336: 4210:

This diversification did not lead to the evolution of any new genera–

4196: 4094: 3992: 3972: 3935: 3618: 3564: 3201: 3073: 2770:, as well as prominent epimeras in the preabdomen unlike the latter. 2378: 2155: 1829: 1646: 1284: 1194: 1024: 890: 171: 151: 97: 41: 9481: 8652: 8611: 8341: 8066: 7533: 4365:

suggests strong evidence of freshwater deposition in the habitat of

4146:

The eurypterids were one of the groups most heavily affected by the

3709:), but this classification is questionable as the morphology of the 2508: 9504: 9394: 9367: 6433: 6230: 5374:, were (or had the potential to be) monophyletic. The monophyly of 5291: 5093: 4492: 4267: 4063: 3988: 3976: 3873: 3869: 3142:

in Illinois (the first species to be described from North America).

3131: 2845: 2197: 1937: 1837: 1642: 1566: 1186: 1178: 1167: 1091: 1075:), a genus of relatively small eurypterids. The largest species of 986: 982: 87: 82: 67: 62: 52: 7669: 7106: 6696: 6589: 6587: 6585: 6583: 6581: 6579: 6577: 4102: 3505:, referring it to the genus due to similarities with the Scottish 2521:

The fragmentary fossil specimens (consisting of only five tergites

2514:

Originally described as the type species of the synonymized genus

2441:(of similar age and stratigraphical formation in Kansas) in 1959. 2300:

Originally described as the type species of the synonymized genus

1870:

Originally described as the type species of the synonymized genus

7997: 7708: 7696: 7623: 7621: 7619: 7617: 7615: 7613: 7611: 7483: 7182: 7163: 6774: 6772: 6770: 6768: 6766: 6764: 6762: 6760: 6525: 6523: 6521: 6519: 6517: 6442: 6418: 6388: 4504: 4359: 4259: 4247: 4239: 4235: 4140: 4106: 3999:, where most of basal adelophthalmid evolution took place in the 3984: 3968: 3805: 3418: 3309: 3283:) in 1888 based on a fossil recovered by an Edward Wilson of the 3049:, is today held in the arthropod paleontology collections of the 1206: 1084: 971: 963: 102: 77: 8463:

Bulletin de l'Institut Royal des Sciences Naturelles de Belgique

7804:"New representative of Merostomata from the Lower Carboniferous" 7657: 7574: 7572: 7506: 7271: 4629:

Line drawings depicting the top and bottom sides of a fossil of

3540:

of similar age and a similar stratigraphical horizon in Kansas,

3300:

Portuguese paleontologist Pereira de Lima described the species

2532:

and shows ornamentation more similar to that seen in the family

8778: 8307:

Shpinev, Evgeniy S.; Filimonov, A. N. (2018). "A New Record of

7919:"Ueber die Crustaceen der Steinkohlenformation von Saarbrücken" 7310: 6574: 6222: 6022: 4316: 4271: 4255: 4016: 3785: 3601: 3576: 3502: 3111:("elegant" or "fine") and Ancient Greek δέρμα (ðerma, "skin"). 2794: 1302:, the spikes running alongside the abdomen being very similar. 1218: 1190: 1061: 933: 161: 8735: 7608: 7077: 7075: 6912: 6910: 6757: 6733: 6514: 3753:

in Germany, to the genus. Poschmann also referred the species

3693:

American paleontologist Roy E. Plotnick referred a species of

3497:) based on a single fossil recovered in New Campbelton in the 3138:, based on fossils recovered in Carboniferous-age deposits at 2758:, differing in a slightly longer and more rounded carapace in 7569: 7423: 7421: 7259: 7207: 7205: 7203: 7096: 7094: 7092: 7090: 7045: 7043: 7003: 7001: 6999: 6997: 6995: 6993: 6991: 6946: 6944: 6942: 6940: 6865: 6863: 6861: 6859: 6745: 6540: 6538: 6328: 4495:(from 298.9 to 295 million years ago), saw the appearance of 4299:

recovered from fossil deposits of Early Carboniferous age in

4275: 4263: 4243: 4231: 3880:, honors the collector of the type specimen, Stefano Piussi. 3865: 3861: 3429:

every known Carboniferous eurypterid to be part of the genus

3015:

Ueber die Crustaceen der Steinkohlenformation von Saarbrücken

2859:, but differing in arrangement of tubercles on the segments. 7300: 7298: 6659: 6657: 6655: 6653: 6651: 6649: 6612: 6610: 6608: 6606: 6604: 6602: 4651:

is classified as part of (and lends its name to) the family

4593:

widespread environments such as the signature Carboniferous

3480:

in 1920, based on fossils discovered in Zhaozezhuang, China.

1713:(differing in size and having a relatively longer prosoma), 1102:

at 15 cm, 6 in), the Carboniferous (the aforementioned

7633: 7584: 7557: 7545: 7072: 6978: 6976: 6963: 6961: 6959: 6907: 6822: 6820: 6818: 6803: 6674: 6672: 6647: 6645: 6643: 6641: 6639: 6637: 6635: 6633: 6631: 6629: 6340: 6323:

located between each lamellae, leaving a space filled with

6124:

fossils are recovered in strata bearing coal (indicating a

4440:

has been recovered from Late Carboniferous deposits in the

4162:. All of these were non-marine groups. Whilst the suborder 2746: