60-437: Slimonidae (the name deriving from the type genus Slimonia , which is named in honor of Welsh fossil collector and surgeon Robert Slimon) is a family of eurypterids , an extinct group of aquatic arthropods . Slimonids were members of the superfamily Pterygotioidea and the family most closely related to the derived pterygotid eurypterids, which are famous for their cheliceral claws and great size. Many characteristics of
120-606: A civil parish. It lies west of the M74 , and southeast of Kirkmuirhill . It is also known as Abbey Green or the Gow . The name means "Enclosure (meaning a walled area, like a monastery or fort) of St Machutus ". The saint was born in Wales and may originally have been known as "Mahagw" prior to emigrating to Brittany where he became known by the Latinised form of the name and also as "St Malo". It
180-468: A flattened telson had convergently evolved . The function of these specialized telsons has historically been controversial and disputed, and whilst study has mainly been focused on telsons within the Pterygotidae, the similarity between the telson of Slimonia and its close relatives should mean that the function would likely have been similar. The pterygotids were hypothesized to have moved by undulating
240-447: A new genus to contain the species, as several distinctive characteristics made the species considerably different from other known species of Pterygotus , among them the shape of the carapace and P. acuminata lacking the large cheliceral claws otherwise characteristic of Pterygotus . The genus was named " Slimonia " after Robert Slimon, honoring the Welsh fossil collector and surgeon who was
300-437: A possible life position. They further argued that since the telson of Slimonia also possessed a keel, this would have created significant drag on it while Slimonia was trying to laterally sweep the telson to stab its prey. Lastly, they argued that the serrations on the telson would most likely be attachment points for setae that would have aided the animal in sensing the water flow to make steering much easier. Visual acuity ,
360-602: A slightly different, tapering, body shape that tapers evenly the whole way instead of suddenly narrowing near the seventh segment as in S. acuminata . The type specimen of S. dubia is a badly preserved carapace, with fragments of various degrees of completion of the first eleven segments found associated. Despite its fragmentary nature, the quadrangular (square) shape of the carapace and the eyes placed at its corners allowed zoologist and paleontologist Malcolm Laurie to place it within Slimonia when describing it in 1899. The size of
420-534: A way similar to in Slimonia ), which suggested a close relation between this species and Slimonia . The family Slimonidae was erected as a taxon by Nestor Ivanovich Novojilov in 1962 to contain the genus Slimonia , which was considered sufficiently distinct from the genera housed in its previous family, the Hughmilleriidae. After several features had been noted that suggested a close relationship between Salteropterus and Slimonia (particularly similarities in
480-466: A weapon. The telson spine, serrated along the sides and exceeding the flattened telson in length, ends in a sharp tip and would likely have been capable of piercing prey. In pterygotids, it is likely that the cheliceral claws came to replace telson spikes as weaponry as the telson spikes of that family are relatively shorter than those of the Slimonidae. However, this theory has been proven to be erroneous as
540-681: Is also possible that the first syllable may mean "garden" rather than "monastery", although Mac an Tailleir (2003) believes the former was altered from the latter in Gaelic. The town has three Christian congregations, namely Lesmahagow Old Parish Church of the Church of Scotland and Abbeygreen Church of the Free Church of Scotland and an Evangelical congregation, (the Hope Hall) on the main street. Roman Catholic residents are served by Our Lady and St John's in
600-461: Is known only from the telson and the metastoma (a large plate part of the abdomen). Both slimonid genera preserve flattened and expanded telsons that end in elongated telson spikes. The discovery of several articulated specimens of Slimonia with the tail segments preserved in tight curves, suggesting that the tail segments were considerably more flexible than previously thought and would have been capable of considerable side-to-side movement. Unlike
660-614: Is simplified from a study by O. Erik Tetlie (2007), and showcases the position of Slimonia relative to the rest of the Eurypterina suborder of eurypterids, with the Stylonurina suborder as an outgroup . Stylonurina Megalograptoidea Eurypteroidea Carcinosomatoidea Waeringopteroidea Adelophthalmoidea Hughmilleria Herefordopterus Slimonia Pterygotidae In 2017, W. Scott Persons IV and John Acorn reported finding an S. acuminata specimen, MB.A 863, in
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#1733106942199720-549: The Patrick Burn Formation of Scotland, dated to the Telychian , around 430 million years ago. The specimen was a complete and articulated series of telsonal, postabdominal and preabdominal segments, and it showed a very strong lateral curvature in the postabdomen. Persons and Acorn admitted that it might have experienced some disarticulation postmortem or could represent a partial molt (exuviae), but concluded that since there
780-607: The Slimonidae , by a variety of characteristics. The prosoma (head) is quadrate (square-shaped) in shape and had small compound eyes on the frontal corners. The bodies were large and cordate (heart-shaped), with a narrow postabdomen and a telson with a strongly expanded anterior half. The chelicerae (frontal appendages) were small in comparison to those of the pterygotids and the walking legs had denticles, but no spines. Genital appendages were long and narrow in both males and females. The type species of Slimonia , S. acuminata ,
840-466: The holotype (BLV15, deposited at the National Museum of Natural History of France ) comprises a well-preserved telson typical of the genus, being laterally inflated and with a dagger-like terminal point. It was anteriorly covered with small scales semilunar to mucronitic ("spined") grouped into a single row of large marginal scales that form a linear serrated edge. A slight dorsal keel is present along
900-407: The pedipalps (the gracile second pair of appendages, behind the chelicerae). Lesmahagow Lesmahagow ( / l ɛ z m ə ˈ h eɪ ɡ oʊ / listen ; Scots : Lismahagie or Lesmahagae , Scottish Gaelic : Lios MoChuda ) is a small town in the historic county of Lanarkshire on the edge of moorland, near Lanark in the central belt of Scotland . Lesmahagow was also
960-410: The Hughmilleriidae, has also been interpreted as the most closely related sister-taxon to the pterygotids. The discovery of Ciurcopterus , currently the most primitive known pterygotid, allowed researchers to study its features which showed that the primitive pterygotid combined characteristics of more derived members of its own family and Slimonia . In particular, the similar appendages shared between
1020-1103: The Pentland Hills, where remains of S. dubia have been found, preserve fossils of a large amount of other eurypterids, including Drepanopterus pentlandicus , Laurieipterus elegans , Parastylonurus ornatus , Hardieopterus macrophthalmus , Carcinosoma scoticus , Stoermeropterus conicus and Pentlandopterus minor . Also preserved are fossils of orthocerids , such as Geisonoceras maclareni . Similar levels of eurypterid diversity are also observed in fossil deposits where other species of Slimonia have been found. S. acuminata has been found associated with Nanahughmilleria lanceolata , Hardieopterus lanarkensis , Eusarcana obesus , Parastylonurus sigmoidalis , Carcinosoma scorpionis and Erettopterus bilobus and S. stylops have been found associated with Nanahughmilleria pygmaea , Eusarcana salteri , Hardieopterus megalops , Erettopterus brodiei , E. gigas , Hughmilleria banksi , Eurypterus cephalaspis and Pterygotus ludensis . The living environment of
1080-468: The Persons and Acorn study claimed that the fossil didn't show any signs of disarticulation, Lamsdell, Marshall, and Briggs showed this is likely not true. They argued that both tergite 8 and 10 clearly overlapped the other tergites in an unnatural way. Furthermore, they noted that the specimen was definitely a molt rather than a carcass, and argued that this meant that the pose the fossil was in did not represent
1140-493: The Slimonidae had small and non-developed chelicerae (frontal appendages) in comparison to the Pterygotidae, which possessed well-developed and powerful cheliceral claws. The type species of Slimonia , S. acuminata , was first described as a species of Pterygotus , " Pterygotus acuminata ", by John William Salter in 1856 based on fossils that had been discovered in Lesmahagow , Scotland . That same year David Page erected
1200-451: The Slimonidae, such as their flattened and expanded telsons (the posteriormost division of their bodies), support a close relationship between the two groups. Slimonids are defined as pterygotioid eurypterids with swimming legs similar to those of the type genus, Slimonia , and the second to fifth pair of appendages being non-spiniferous. The family contains only two genera, the almost completely known Slimonia and Salteropterus , which
1260-462: The abdominal segments), Salteropterus was finally classified as a slimonid in 1989 by Victor P. Tollerton. The large and flattened telson of Slimonia (it is also flattened in Salteropterus , but not to the full extent of that of Slimonia ) is distinctive and shared only with the pterygotid eurypterids and with the derived hibbertopterid Hibbertopterus and mycteroptid Hastimima , where
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#17331069421991320-583: The appendages of both slimonid genera unites them as a group and showcases that they are more derived than the hughmilleriids, on which spines appear on four to five of their podomeres (leg segments). Hughmilleria Herefordopterus Slimonia Salteropterus Pterygotidae Slimonia 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
1380-513: The body and appendages. In some arthropods, pustules serve as attachment points of setae (bristle- or hair-like structures with sensory functions). Similar pustule rows have been discovered in the other eurypterid Drepanopterus abonensis , a sweep-feeder that used the marginal rim to search the substrate of its living environment for prey. If the pustules of S. acuminata had setae, these pustules may have functioned as tactile and sensory organs used for locating and identifying prey, together with
1440-450: The body was very stiff, and that the flattened telson would likely have served as a rudder that would have allowed the animals to be agile and capable of quick turns when chasing after prey, contradicting previous hypotheses that the telson would have served a propulsive function. Whilst the postabdomen of Slimonia was likely similarly stiff and inflexible dorsally (up and down), Persons and Acorn claimed that their specimen suggested that it
1500-417: The body would require muscular contractions, but no major apodemes (internal ridges of the exoskeleton that supports muscular attachments) or any muscle scars indicative of large opisthosomal muscles have been found. Instead, propulsion was likely generated by the sixth pair of appendages, the swimming legs used by other eurypterine eurypterids. Whilst stiff dorsally, fossil evidence suggests that Slimonia
1560-416: The carapace suggests that the species would have grown to 12 cm (5 in) in length. Another species, S. stylops , was first considered a species of Pterygotus when described by John William Salter in 1859, and the highly fragmentary nature of the known fossils make a precise identification difficult and problematic. Only one specimen, the anterior part of a carapace with the compound eyes placed on
1620-402: The clarity of vision, can be determined in arthropods by determining number of lenses in their compound eyes and the interommatidial angle (shortened as IOA and referring to the angle between the optical axes of the adjacent lenses). The IOA is especially important as it can be used to distinguish different ecological roles in arthropods, being low in modern active arthropod predators. Slimonia
1680-403: The enlarged cheliceral claws of the pterygotids and was smaller in size than the largest members of that group. Prey likely included jawless fish such as heterostracans and early osteostracans , which Slimonia would have seized with its frontal appendages. Slimonia traversed its living environment on spindly legs or through using its swimming appendages. The lungs of the genus were located on
1740-508: The entire opisthosoma (the large posterior section of the body) by moving the abdominal plates, as such undulations of the opisthosoma and telson would have acted as the propulsive method of the animal, rendering the swimming legs used by other eurypterid groups useless. Fossil evidence contradicts such an hypothesis however, as eurypterid bodies were stiff dorsally (up and down) and preserve no evidence for any sort of tapering or other mechanism that would have increased flexibility. Any flexing of
1800-459: The family Hughmilleriidae in 1951 by Erik N. Kjellesvig-Waering. Nestor Ivanovich Novojilov classified Slimonia as part of a family of its own in 1968. Slimonia is one of the most closely related genera to the pterygotid family and the Slimonidae is often interpreted as a sister-taxon to the Pterygotidae. The other Pterygotioid family, the Hughmilleriidae , has also been interpreted as
1860-495: 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. Out of
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1920-430: The feature convergently evolved). The pterygotid telson was in general slightly larger than that of Slimonia and was more slender. The telson spike of Slimonia was much longer than any seen in the Pterygotidae (constituting just over half of the total telson length) however, serrated and ending in a fine point. The largest species of Slimonia , S. acuminata , reached a maximum length of 100 cm (39 in) whilst
1980-520: The first to discover eurypterid fossils in Lesmahagow. In the late 1800s and early 1900s new specimens were discovered of a previously fragmentary species of Eurypterus , E. abbreviatus , in Herefordshire , England . One of these specimens, BGS GSM Zf-2864 (discovered in 1939), revealed a very distinct telson and features similar to Slimonia (such as the last three opisthosomal segments tapering in
2040-411: The fossil specimen in question was a molt, rather than an actual carcass, and did show apparent signs of disarticulation. The telson of Salteropterus is very distinctive and though its function remains unknown (possibly used for additional balancing), it was likely not used as a weapon in the same way the telson of Slimonia was. The flattened portion is trigonal and smaller than that of Slimonia but
2100-439: The four described species of Slimonia , three measured below or up to 20 centimetres (7.9 in) in length. Only S. acuminata was larger, with the largest specimens measuring 100 centimetres (39 in) in length. Though this is large for a predatory arthropod, Slimonia would be exceeded in length by later and more derived (more "advanced") members of the closely related pterygotid family of eurypterids, which would become
2160-432: The frontal prosoma (head) and posterior opisthosoma (abdomen). The appendages were attached to the prosoma, and were characterized in slimonids as being non-spiniferous (lacking spines). The telson (the posteriormost division of the body) was expanded and flattened (similarly to the telsons of the more derived pterygotid eurypterids) and ended in a thin and elongated telson spike. In Salteropterus , this telson spike
2220-502: The largest known arthropods to ever live. Slimonia is in many ways similar to the more derived (more "advanced") eurypterids of its superfamily, the Pterygotioidea . In particular, the expanded and flattened telson (the most posterior segment of the body) of Slimonia is similar to that of the pterygotid eurypterids and is a feature that Slimonia and the pterygotids only share with some derived hibbertopterid eurypterids (where
2280-446: The largest known species, with the largest specimens measuring up to 100 cm (39 in) in length. In 1899, an additional species, S. dubia , would be referred to the genus. This species was recovered from slightly earlier deposits (Llandovery age) in the Pentland Hills of Scotland and could be distinguished from S. acuminata by the more elongated telson (also not as broad in the parts furthest back), thinner telson spike and
2340-421: The margin, is known and though it does resemble Slimonia , it could also potentially be referred to Hughmilleria or even represent the carapace of Salteropterus abbreviatus (a closely related slimonid eurypterid known only from the telson and metastoma , a large plate part of the abdomen). The fossils were recovered from deposits of Pridoli (Late Silurian) age in Herefordshire , England and suggest that
2400-404: The most closely related sister-taxon to the pterygotids. The discovery of Ciurcopterus , the most primitive known pterygotid, and studies revealing that Ciurcopterus combines features of Slimonia (the appendages are particularly similar) and of more derived pterygotids, revealed that the Slimonidae is more closely related to the Pterygotidae than the Hughmilleriidae is. The cladogram below
2460-539: The neighbouring village of Blackwood , 3 miles (5 km) away. Lesmahagow Priory , founded by Benedictine monks in 1144, no longer stands but its foundations were excavated in 1978 and are located next to the Old Parish Church off Church Square. The Scottish branch of the International Society for Krishna Consciousness operates from Lesmahagow. Clydesdale International Twinning Association (CITA)
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2520-427: The other pterygotioid eurypterid families (Pterygotidae and Hughmilleriidae ), even though several defining traits are known of Slimonia . Many of the unique traits of Slimonia are found in the carapace (the "head"), which is not known in Salteropterus . Among these is the quadrate (square) shape of the carapace itself and the placement of the compound eyes on the frontal corners. Though they were closely related,
2580-446: The pterygotids differed from genus to genus, with some (such as Pterygotus ) being found in estuaries, while other (such as Jaekelopterus ) were found in freshwater environments; Slimonia has been found in environments which appear to have been intertidal to marine, Patrick Burn Formation for example is estimated to be non-marine or marginal marine or just marine environment. Slimonia likely preyed on smaller fish, as it lacked
2640-524: The related pterygotids, the slimonids did not possess robust and powerful cheliceral claws and as such, these telson spikes may have been the primary weaponry used by Slimonia , although this theory is considered unlikely by contemporary researchers. The telson spike of Salteropterus was likely not used as a weapon and was highly distinct and different from that of any other eurypterid. Slimonid eurypterids ranged in size from 12 centimetres (5 inches) to 100 centimetres (39 inches) in length. The largest species
2700-402: The smallest, S. dubia , grew to 12 cm (5 in) in length. Though 100 cm is large for a predatory arthropod, Slimonia would be exceeded in length by later and more derived (more "advanced") members of the closely related pterygotid family of eurypterids, which would become the largest known arthropods to ever live. Slimonia can be distinguished from other members of its family,
2760-455: The species considerably different from other known species of Pterygotus , among them the shape of the carapace and S. acuminata lacking the large cheliceral claws known from Pterygotus . The generic name is derived from and honors Robert Slimon, a fossil collector and surgeon from Lesmahagow. Slimon was the first to discover eurypterid fossils in Lesmahagow, bringing them to the attention of Roderick Murchison in 1851. S. acuminata remains
2820-523: The species grew to 12 cm (5 in) in length. Due to its problematic nature, S. stylops is seen as a nomen dubium by modern researchers. In 1973, another species of Slimonia was named by Kjellesvig-Waering based on one single fossil recovered by Eduardo Rodriguez from the Kirusillas Formation , of Ludlow - Pridoli (Late Silurian) age, in Cochabamba , Bolivia . Named S. boliviana ,
2880-560: The telson spike is far longer, forming something akin to a stem with knobs running alongside it and ending in a tri-lobed organ unseen in any other eurypterid. Slimonid eurypterids are classified as part of the Pterygotioidea superfamily, within the Diploperculata infraorder and Eurypterina suborder. The Slimonidae is often interpreted as a sister-taxon (the most closely related group) to the Pterygotidae. The other Pterygotioid family,
2940-404: The telson. There was a triangular area at the base of the telson which could have been a point of union with the muscles. S. boliviana differed from S. acuminata in having the keel much less developed, narrower and not reaching the terminal spike. The latter was wider, not as pointed and with less developed serrations. The telson itself was wider and shorter than in the type species. This species
3000-532: The two genera suggested that the Slimonidae was the most closely related group to the Pterygotidae. Hughmilleriid eurypterids are thus seen as a group more basal than both the slimonids and the pterygotids. The cladogram below is based on the conclusions drawn by O. Erik Tetlie (2004) on the phylogenetic positions of Herefordopterus , Salteropterus and the Pterygotioidea at large following his redescriptions of various eurypterids from Herefordshire , England , including Salteropterus . The partial lack of spines on
3060-457: The underside of the body in a series of folds. Like many eurypterid species, Slimonia acuminata requires a modern re-description to properly establish defining traits and characteristics. Some traits that appear to be unique to S. acuminata have been described based on specimens housed at the Doncaster Museum and Art Gallery , including rows of pustules (bulges) along the marginal rim of
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#17331069421993120-473: Was Slimonia acuminata , which was also the first slimonid to be described and is known from the Early to Middle Silurian of Lesmahagow , Scotland . Like all other chelicerates , and other arthropods in general, slimonid eurypterids possessed segmented bodies and jointed appendages (limbs) covered in a cuticle composed of proteins and chitin . The chelicerate body is divided into two tagmata (sections);
3180-410: Was even more elongated than in Slimonia and ended in a tri-lobed structure unique to the genus. Though Slimonia itself is very well known, the other genus of the family, Salteropterus , is less well known with its fossils only preserving the telson and the metastoma (a large plate part of the abdomen). As such it is difficult to establish exactly which traits distinguish the family as a whole from
3240-406: Was first described as a species of Pterygotus , " Pterygotus acuminata " ( acuminata being Latin for "sharp" or "tapering"), by John William Salter in 1856, based on fossils recovered from deposits of Llandovery - Wenlock (Early to Middle Silurian) age in Lesmahagow , Scotland . That same year David Page erected a new genus to contain the species, as several distinctive characteristics made
3300-423: Was highly flexible laterally (side to side). As such, they theorised that the tail may have been used as a weapon. The telson spine, serrated along the sides and exceeding the flattened telson in length, ends in a sharp tip, and they proposed that it could have been capable of piercing prey. However, the Persons and Acorn theory was challenged in 2018 by James Lamsdell, David Marshall, and Derek Briggs. Even though
3360-435: Was no apparent disarticulation in the metasoma, it was likely that the articulation seen in the postabdominal segments (which is also seen in some other eurypterid fossils, such as of Eurypterus and Alkenopterus ) would have been possible in life. Biomechanical studies on the telsons and postabdominal segments of eurypterids closely related to Slimonia , particularly those of the family Pterygotidae , had revealed that
3420-497: Was set up in 1975 to promote the benefits of twinning to all sections of the local community. This organisation mainly focuses on the larger towns in the old Clydesdale council area. The Highland Games are held annually in June with Pipe Bands competing in Grades 1 through 4. There are also events for Highland dancing, weight over the bar, tossing the caber and archery. The first Highland Games
3480-517: Was the third Silurian eurypterid in the Southern Hemisphere to be described, the other two coming from Australia . The fossil suggest a total body length of 20 centimetres (7.9 in). Slimonia is classified as part of the eurypterid family Slimonidae , within the superfamily Pterygotioidea . Historically Slimonia was first considered a member of the Pterygotidae, until it was reclassified alongside Hughmilleria and other genera to
3540-425: Was very flexible laterally (side to side). A specimen of Slimonia acuminata from the Patrick Burn Formation of Scotland preserves a complete and articulated series of telsonal, postabdominal and preabdominal segments. In the specimen, the "tail" is bent to a considerable degree previously unseen in any eurypterid. Capable of bending its tail from side to side, it has been theorised that the tail may have been used as
3600-543: Was very similar to the basal pterygotid Erettopterus in terms of visual acuity, with the number of lenses being comparable to those of Pterygotus and Jaekelopterus and possessing an IOA between 2 and 3 (which is higher than the IOA of Pterygotus and Jaekelopterus , suggesting that the visual acuity of Slimonia was good, but not as good as in the derived pterygotids). Fossils of Slimonia have been recovered in deposits home to diverse eurypterid faunas. Telychian deposits in
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