Pittsfordipterus Temporal range: Ludfordian, | |
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Restoration of the carapace of P. phelpsae | |
Scientific classification ![]() | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Subphylum: | Chelicerata |
Order: | † Eurypterida |
Superfamily: | † Adelophthalmoidea |
Family: | † Adelophthalmidae |
Genus: | † Pittsfordipterus Kjellesvig-Waering & Leutze, 1966 |
Type species | |
†Pittsfordipterus phelpsae Ruedemann, 1921 |
Pittsfordipterus ("wing from Pittsford") 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.
Pittsfordipterus was a basal ("primitive") genus that was distinguished from the more derived adelophthalmids by the specialization of its genital operculum (a plate-like segment which contains the genital aperture) and its long and narrow eyes, being Bassipterus ' closest relative. With an estimated length of 6 cm (2.4 in), Pittsfordipterus was one of the smallest adelophthalmids.
Like the other adelophthalmid eurypterids, Pittsfordipterus was a small eurypterid. The total size of the largest known specimen is estimated at only 6 cm (2.4 in), making it one of the smallest adelopththalmids and eurypterids overall. [1]
Pittsfordipterus had a broad carapace (dorsal shield of the head) with elongated and narrow eyes placed away from the head margin. [2] In the largest specimen (the paratype), the carapace was 18 mm (0.7 in) wide and 13 mm (0.5 in) long. Five parallel lines along the front margin that make up the ornamentation can be seen on the surface of the carapace. In the posterior portion, a series of small irregularly distributed tubercles (rounded protuberances) appear. In the posterior margin, there is a strip of fine triangular scales. The tergites (the dorsal part of the body segments) also present three to four parallel lines along the posterior margin, followed by five lines that end in a series of separate and lunate (crescent-shaped) scales. [3]
Its genital operculum (a plate-like segment which contains the genital aperture) is the main characteristic that distinguishes it from the rest of the derived (more "advanced") adelopththalmids, showing characteristics indicative of the more basal eurypterid Eurypterus . It possessed two opercular flaps, two protruding extensions lateral to the genital appendage. The genital appendage (which is of type A, assumed to represent females) had a great length, extending beyond the second abdominal plate. It was divided into two joints. The first was approximately hastate (with protruding lobes) and was ornamented with fine scales. It was followed by a tubular (tube-shaped) joint that lacked ornamentation. The second joint was less broad and long. The distal end (the farthest from the junction point) widens, with a pair of sharp lateral projections ("protuberances"). This gives it a termination finished in three spines similar to those that occur in the genital appendage (of type A) in Slimonia and Adelophthalmus . The American paleontologist Erik Norman Kjellesvig-Waering predicted that the genital operculum would end up being a feature of great phylogenetic importance at least at the generic level. [4]
Pittsfordipterus is only known by two well preserved specimens, the holotype and paratype (NYSM 10102 and NYSM 10103, both at the New York State Museum). [5] In 1921, the American paleontologist Rudolf Ruedemann described the species Hughmilleria phelpsae from the Vernon Formation of the New York state. Ruedemann noted several differences between his new species and H. socialis (type species of Hughmilleria ), including the size of the carapace (broader and shorter than in the latter), the position of the eyes further from the margin (as opposed to the marginal position of H. socialis) and the morphology of the genital appendage. Instead, Ruedemann suggested a relationship between H. phelpsae and the species H. shawangunk based on the size of the carapace and the position of the eyes more or less being similar, as well as the same linear ornamentation. However, while in its ventral part, H. shawangunk had the same linear ornamentation, H. phelpsae had imbricate scales similar to those of H. socialis. Even so, he suggested that H. phelpsae could probably represent a late descendant of H. shawangunk. [3]
In the description of the genus Parahughmilleria in 1961, Kjellesvig-Waering suggested that H. phelpsae should be classified under this new genus. [6] Three years later, Kjellesvig-Waering decided to assign the same species to the subgenus Nanahughmilleria . [4] In 1966, Kjellesvig-Waering, together with the American paleontologist Kenneth Edward Caster, recognized that H. (N.) phelpsae was sufficiently different from the other eurypterids and erected the genus Pittsfordipterus based on the morphology of its genital appendage. [7] The name Pittsfordipterus is translated as "wing from Pittsford", with the first word of the name referring to the type locality (the location where it was initially found) and the last word composed of the Greek word πτερόν ( pteron , wing). [8]
Pittsfordipterus is classified as part of the family Adelophthalmidae, the only clade ("group") within the superfamily Adelophthalmoidea. [9] P. phelpsae was originally described as a species of the genus Hughmilleria, but it was considered different enough to represent a new separate genus in 1966. [7]
In 2004, O. Erik Tetlie erected the family Nanahughmilleridae in an unpublished thesis to contain the adelophthalmoids with no or reduced genital spatulae (a long, flat piece in the operculum) and the second to fifth pair of prosomal (of the prosoma, "head") appendages (limbs) of Hughmilleria-type (hypothetical since the appendages of Pittsfordipterus are unknown). This family contained Nanahughmileria, Pittsfordipterus and perhaps Parahughmilleria. [5] However, the clade has almost never been used in subsequent studies and lists of eurypterids, [10] and instead, they classify the nanahughmillerids as part of Adelophthalmidae. [9] A derived clade in which Nanahughmilleria is closest to Parahughmilleria and Adelopththalmus is better supported, as well as a basal (more "primitive") group consisting of Pittsfordipterus and Bassipterus . This clade is backed by a pair of synapomorphies (shared characteristics different from that of their latest common ancestor), relatively long and narrow eyes and a complex termination of the genital appendage. Therefore, Pittsfordipterus is the sister group (closest relative) of Bassipterus. [2]
The cladogram below presents the inferred phylogenetic positions of most of the genera included in the three most derived superfamilies of the Diploperculata infraorder of eurypterids (Adelophthalmoidea, Pterygotioidea and the waeringopteroids), as inferred by Odd 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]
Pittsfordipterus fossils have been recovered from Silurian deposits of the Late Ludlow (Ludfordian) epoch of the Vernon Formation of the New York state. [1] [3] In this formation, fossils of other eurypterids have been found, such as Eurypterus pittsfordensis or Mixopterus multispinosus , as well as indeterminate species of phyllocarids, leperditiids and cephalopods. The lithology of the place consists of dark gray to black shale with abundant gypsum and dolomite slabs that reach a combined thickness of 305 m (1,000 ft). It is also possible to find green shale and very rarely, red shale. This habitat was probably lagoonal. [11] [3]
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.
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.
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.
Hibbertopterus is a genus of eurypterid, a group of extinct aquatic arthropods. Fossils of Hibbertopterus have been discovered in deposits ranging from the Devonian period in Belgium, Scotland and the United States to the Carboniferous period in Scotland, Ireland, the Czech Republic and South Africa. The type species, H. scouleri, was first named as a species of the significantly different Eurypterus by Samuel Hibbert in 1836. The generic name Hibbertopterus, coined more than a century later, combines his name and the Greek word πτερόν (pteron) meaning "wing".
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.
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.
Nanahughmilleria 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.
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.
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.
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.
Unionopterus is a genus of eurypterid, an extinct group of aquatic arthropods commonly known as "sea scorpions". Fossils have been registered from the Early Carboniferous period. The genus contains only one species, U. anastasiae, recovered from deposits of Tournaisian to Viséan stages in Kazakhstan. Known from one single specimen which was described in a publication of Russian language with poor illustrations, Unionopterus' affinities are extremely poorly known.
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.
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.
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.
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.
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.
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.
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.
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.
Pruemopterus is a genus of eurypterid, an extinct group of aquatic arthropods. The type and only species of Pruemopterus, P. salgadoi, is known only from a single fossil specimen discovered in geological deposits of Early Devonian age in Germany. The name of the genus is derived from the Prüm river and the surrounding Prüm valley, which contains the finding place of the fossil, and the Ancient Greek πτερόν, referring to the eurypterid swimming paddles, and the species name honors the Brazilian photographer and photojournalist Sebastião Salgado.