| Kirktonecta | |
|---|---|
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Subclass: | † Lepospondyli |
| Order: | † "Microsauria" |
| Genus: | † Kirktonecta Clack, 2011 |
| Species: | †K. milnerae |
| Binomial name | |
| †Kirktonecta milnerae Clack, 2011 | |
Kirktonecta is an extinct genus of microsaur known from the Carboniferous of West Lothian, Scotland. [1]
Kirktonecta is known from the holotype specimen UMZC 2002, a and b, an almost complete skeleton including the skull, and preserved evidence for soft tissues, in part (slab a) and counterpart (slab b). The holotype was collected in the East Kirkton Quarry, near Bathgate of West Lothian, from "Bed 82" East Kirkton Limestone of the Bathgate Hills Volcanic Formation, dating to the Brigantian substage, of the late Viséan stage, of the Dinantian series (Early Carboniferous), about 333–328.3 million years ago. It represents the first microsaur to be discovered in the United Kingdom and the earliest occurrence of a microsaur in the fossil record. The next oldest being Utaherpeton and an unnamed taxon from the Chesterian of Goreville, Illinois. [1]
Kirktonecta is diagnosed by the following autapomorphies: "deep tail, comprised of long, posteriorly directed, round-ended haemal spines in contact along their anterior and posterior margins distally, combined with low rounded neural spines; large pes, with tarsus breadth equivalent to the length of 3.5 or 4 presacral vertebrae." Jennifer A. Clack, who named this genus, found it to be most closely related to basal microsaurs, such as Asaphestera , Saxonerpeton , Hyloplesion and Llistrofus . [1]
Kirktonecta was first named by Jennifer A. Clack in 2011 and the type species is Kirktonecta milnerae. The generic name is derived from the name of the East Kirkton Quarry, where the holotype was found, and Greek necta, "swimmer". The specific name honours the paleontologist Angela C. Milner. [1]
West Lothian is one of the 32 council areas of Scotland, and was one of its historic counties. The county, which was known as Linlithgowshire, was bounded geographically by the Avon to the west and the Almond to the east. The modern council area occupies a larger area than the historic county. It was reshaped following local government reforms in the late 20th century: some areas in the west were transferred to Falkirk; some areas in the east were transferred to Edinburgh; and some areas that had formerly been part of in Midlothian were added.
Livingston is the largest town in West Lothian, Scotland. Designated in 1962, it is the fourth post-war new town to be built in Scotland. Taking its name from a village of the same name incorporated into the new town, it was originally developed in the then-counties of Midlothian and West Lothian. It is situated approximately fifteen miles (25 km) west of Edinburgh and thirty miles (48 km) east of Glasgow, and is close to the towns of Broxburn to the north-east and Bathgate to the north-west.
Jennifer Alice Clack, was an English palaeontologist and evolutionary biologist. She specialised in the early evolution of tetrapods, specifically studying the "fish to tetrapod" transition: the origin, evolutionary development and radiation of early tetrapods and their relatives among the lobe-finned fishes. She is best known for her book Gaining Ground: the Origin and Early Evolution of Tetrapods, published in 2002 and written with the layperson in mind.
Bathgate is a town in West Lothian, Scotland, 5 miles (8 km) west of Livingston and adjacent to the M8 motorway. Nearby towns are Armadale, Blackburn, Linlithgow, Livingston, West Calder and Whitburn. Situated 2 miles (3 km) south of the ancient Neolithic burial site at Cairnpapple Hill, Bathgate and the surrounding area show signs of habitation since about 3500 BC.
Romer's gap is an example of an apparent gap in the tetrapod fossil record used in the study of evolutionary biology. Such gaps represent periods from which excavators have not yet found relevant fossils. Romer's gap is named after paleontologist Alfred Romer, who first recognised it. Recent discoveries in Scotland are beginning to close this gap in palaeontological knowledge.
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".
Westlothiana is a genus of reptile-like tetrapod that lived about 338 million years ago during the latest part of the Visean age of the Carboniferous. Members of the genus bore a superficial resemblance to modern-day lizards. The genus is known from a single species, Westlothiana lizziae. The type specimen was discovered in the East Kirkton Limestone at the East Kirkton Quarry, West Lothian, Scotland in 1984. This specimen was nicknamed "Lizzie the lizard" by fossil hunter Stan Wood, and this name was quickly adopted by other paleontologists and the press. When the specimen was formally named in 1990, it was given the specific name "lizziae" in homage to this nickname. However, despite its similar body shape, Westlothiana is not considered a true lizard. Westlothiana's anatomy contained a mixture of both "labyrinthodont" and reptilian features, and was originally regarded as the oldest known reptile or amniote. However, updated studies have shown that this identification is not entirely accurate. Instead of being one of the first amniotes, Westlothiana was rather a close relative of Amniota. As a result, most paleontologists since the original description place the genus within the group Reptiliomorpha, among other amniote relatives such as diadectomorphs and seymouriamorphs. Later analyses usually place the genus as the earliest diverging member of Lepospondyli, a collection of unusual tetrapods which may be close to amniotes or lissamphibians, or potentially both at the same time.
Casineria is an extinct genus of tetrapod which lived about 340-334 million years ago in the Mississippian epoch of the Carboniferous period. Its generic name, Casineria, is a latinization of Cheese Bay, the site near Edinburgh, Scotland where the holotype fossil was found. When originally described in 1999, it was identified as a transitional fossil noted for its mix of basal (amphibian-like) and advanced (reptile-like) characteristics, putting it at or very near the origin of the amniotes, the group containing all mammals, birds, modern reptiles, and other descendants of their reptile-like common ancestor. However, the sole known fossil is lacking key elements such as a skull, making exact analysis difficult. As a result, the classification of Casineria has been more controversial in analyses conducted since 1999. Other proposed affinities include a placement among the lepospondyls, seymouriamorphs, "gephyrostegids", or as a synonym of Caerorhachis, another controversial tetrapod which may have been an early temnospondyl.
Eucritta is an extinct genus of stem-tetrapod from the Viséan epoch in the Carboniferous period of Scotland. The name of the type and only species, E. melanolimnetes is a homage to the 1954 horror film Creature from the Black Lagoon.
Pulmonoscorpius kirktonensis is an extinct species of scorpion that lived during the Viséan and Serpukhovian ages of the Carboniferous period, around 336.0 – 326.4 million years ago.
Balanerpeton is an extinct genus of temnospondyl amphibian from the Visean stage of the Early Carboniferous period. It reached approximately 50 cm (20 in) in length. Balanerpeton woodi was discovered by Stanley Wood and is the earliest and most common tetrapod in the East Kirkton Limestone of the East Kirkton Quarry assemblage of terrestrial amphibians in Scotland. Characteristics of Balanerpeton woodi include the presence of large external nares, large interpterygoid vacuities, and an ear with a tympanic membrane and rod-like stapes. Numerous studies and research regarding ontogeny in non extant taxa have been oriented around this taxon. The morphology of the stapes suggests that the animal was capable of hearing high-frequency sound. B. woodi does not possess lateral line sulci or an ossified branchial system. The principal method of respiration was probably buccal rather than costal, indicated by the small straight ribs.
Silvanerpeton is an extinct genus of early reptiliomorph found in East Kirkton Quarry of West Lothian, Scotland, in a sequence from the Brigantian substage of the Viséan. The find is important, as the quarry represents terrestrial deposits from Romer's gap, a period poor in fossils where the higher groups labyrinthodonts evolved. Based on a remarkably well preserved humerus and other traits, the animal is believed to have been an advanced reptiliomorphs, close to the origin of amniotes.
Acherontiscus is an extinct genus of stegocephalians that lived in the Early Carboniferous of Scotland. The type and only species is Acherontiscus caledoniae, named by paleontologist Robert Carroll in 1969. Members of this genus have an unusual combination of features which makes their placement within amphibian-grade tetrapods uncertain. They possess multi-bone vertebrae similar to those of embolomeres, but also a skull similar to lepospondyls. The only known specimen of Acherontiscus possessed an elongated body similar to that of a snake or eel. No limbs were preserved, and evidence for their presence in close relatives of Acherontiscus is dubious at best. Phylogenetic analyses created by Marcello Ruta and other paleontologists in the 2000s indicate that Acherontiscus is part of Adelospondyli, closely related to other snake-like animals such as Adelogyrinus and Dolichopareias. Adelospondyls are traditionally placed within the group Lepospondyli due to their fused vertebrae. Some analyses published since 2007 have argued that adelospondyls such as Acherontiscus may not actually be lepospondyls, instead being close relatives or members of the family Colosteidae. This would indicate that they evolved prior to the split between the tetrapod lineage that leads to reptiles (Reptiliomorpha) and the one that leads to modern amphibians (Batrachomorpha). Members of this genus were probably aquatic animals that were able to swim using snake-like movements.
Trihecaton is an extinct genus of microsaur from the Late Pennsylvanian of Colorado. Known from a single species, Trihecaton howardinus, this genus is distinctive compared to other microsaurs due to possessing a number of plesiomorphic ("primitive") features relative to the rest of the group. These include large intercentra, folded enamel, and a large coronoid process of the jaw. Its classification is controversial due to combining a long body with strong limbs, features which typically are not present at the same time in other microsaurs. Due to its distinctiveness, Trihecaton has been given its own monospecific family, Trihecatontidae.
Ossinodus is an extinct genus of stem tetrapod. Fossils have been found from the Ducabrook Formation in Queensland, Australia dating back to the middle Visean stage of the Early Carboniferous (Mississippian). It was originally placed within the family Whatcheeriidae, but the absence of an intertemporal bone as suggested by a recent reconstruction of the skull based on fragmentary material may prove it to be stemward of all whatcheeriids.
East Kirkton Quarry is a former limestone quarry in West Lothian, Scotland, now better known as a fossil site known for terrestrial fossils from the fossil-poor Romer's gap, a 15 million year period at the beginning of the Carboniferous. The rocks and fossils are of Visean age, about 335 million years old. Best known are the labyrinthodont fossils, as the period coincides with the time where the modern lineages of tetrapods are thought to have evolved.
Eldeceeon is an extinct genus of reptiliomorph from the Mississippian of Scotland. It is known from two fossil specimens found within the Viséan-age East Kirkton Quarry in West Lothian. The type and only species, E. rolfei, was named in 1994. Eldeceeon is thought to be closely related to embolomeres, but it has several distinguishing features including long limbs and a short trunk. Initially known from two crushed partial skeletons, additional specimens have been reported by Ruta & Clack (2006).
Mycteropoidea is an extinct superfamily of eurypterids, an extinct group of chelicerate arthropods commonly known as "sea scorpions". It is one of four superfamilies classified as part of the suborder Stylonurina. Mycteropoids have been recovered from Europe, Russia, South America and South Africa. Mycteropoid specimens are often fragmentary, making it difficult to establish relationships between the included taxa. Only two mycteropoid taxa are known from reasonable complete remains, Hibbertopterus scouleri and H. wittebergensis.
Eobaphetes is an extinct genus of embolomere which likely lived in the Pennsylvanian of Kansas. The genus is based on several skull and jaw fragments of a single individual. They were originally described under the species Erpetosuchus kansasensis, but this was later changed to Eobaphetes kansasensis when it was determined that Erpetosuchus was preoccupied by a Triassic reptile.
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