1. Stylonurus powriensis 2. Brontoscorpio anglicus 3. Pulmonoscorpius kriktonensis
Brontoscorpio anglicus ("English thunder scorpion") was a 1-metre long aquatic scorpion that lived during the Silurian period. When alive, B. anglicus would have resembled an oversized scorpion, albeit with relatively large (for a scorpion) compound eyes; it was an important predator of its time, given that the arthropods were among the largest animals on Earth during the Silurian.
All post-Paleozoic scorpions are terrestrial, while during the Silurian many of the known taxa made the transition from aquatic to terrestrial environments. It has been inferred that Brontoscorpio was capable of leaving the water and entering land, whether to evade other predators, such as large nautiloids, eurypterids, or even other aquatic scorpions; or pursue prey, such as other, smaller terrestrial scorpions. However, given its great size, B. anglicus had to return to the water when it tired of supporting its own weight, or at the very least whenever it moulted its exoskeleton (on land, it would risk being crushed by its own mass). Marine scorpions such as B. anglicus captured, stung, and ate small sea animals such as fish like acanthodians, heterostracans, smaller scorpions and trilobites.
As with other arachnids, such as modern scorpions, Brontoscorpio respired through gas exchange via pores in its exoskeleton and the inner linings of its book lungs. Its tail was tipped with a large, venomous stinger that was, according to Walking with Monsters, the size of a light bulb.
Pulmonoscorpius kirktonensis (literally breathing scorpion) is a giant species of extinct scorpion that lived during the Viséan epoch of the Carboniferous. Its fossils were found at East Kirkton, West Lothian in Scotland. In life, this species grew to 70 centimetres (28 in) and even over a 1meter (40 in) in length.
Like the giant Meganeura, Pulmonoscorpius is thought to have achieved its large size from the higher oxygen content of the air of the Carboniferous period. The superficial morphology of Pulmonoscorpius is that of a larger version to today’s scorpions, although its proportionally larger eyes have led to the suggestion that it may have been a more visually orientated hunter.
It is impossible to say how toxic the venom of Pulmonoscorpius would have been, but a good rule of thumb is that the smaller the pincers are in relation to the thickness of the tail, the more potent the venom, with the thicker tails holding larger amounts.This holds true to today’s scorpions with those that have small pincers and fat tails being more feared by people who have become accustomed to their presence.
It is also hard to say with certainty what the diet of Pulmonoscorpius would have been, although as a scorpion it would almost certainly have been carnivorous. It may have focused its attentions upon other large arthropods, and maybe even the smaller amphibians and early reptiles. One clue may be the relatively small size of the pincers, indicating either a focus on prey smaller than itself, or a greater reliance on its venom to take down larger prey which was then manipulated with the pincers when dead.
Note!!! In modern pop culture and nightmares of men is full of giant spiders.For many people they come from prehistoric times,when everything was greater than now.The truth is that the biggest spiders now live alongside us.The biggest prehistoric spider was Mongolarachne. Female total body length estimated at 24.6 millimeters long, with forwards length 56.5 millimetres long. Male total body length 16.54 millimetres long. For comparison the largest species of arachnid by length is probably the giant huntsman spider (Heteropoda maxima) of Laos, which in 2008 replaced the Goliath birdeater (Theraphosa blondi) of northern South America as the largest known spider by leg-span.However the most massive arachnids, of comparable dimensions and possibly even greater mass, are the Chaco golden knee, Grammostola pulchripes, and the Brazilian salmon pink, Lasiodora parahybana. The huntsman spider may span up to 29 cm (11 in) across the legs, while in the New World "tarantulas" like Theraphosa can range up to 26 cm (10 in).In Grammostola, Theraphosa and Lasiodora, the weight is projected to be up to at least 150 g (5.3 oz) and body length is up to 10 cm (3.9 in).
Mongolarachne jurassica is an extinct spider placed in the monotypic family Mongolarachnidae.The species was originally described as Nephila jurassica and placed in the living genus Nephila which contains the golden silk orb-weavers.Subsequently it was determined to be stem-orbicularian, i.e. a relative of the group Orbiculariae, which contains the family Nephilidae, but also several other families, such as Theridiidae, Theridiosomatidae or Uloboridae.The species is known only from the Middle Jurassic Jiulongshan Formation, part of the Daohugou Beds, near the village of Daohugou in Ningcheng County, northeastern China.
Mongolarachne was originally described in 2011 as Nephila jurassica, a prehistoric species of the Nephila genus of orb weaving spiders that we know today. Nephila jurassica made headlines at the time because it was the largest known spider in the fossil record, though comparable in size to modern golden orb weaver spiders that are alive today. It was also credited as being the oldest known species of the Nephila genus, extended the temporal range of the genus back one hundred and thirty million years.
The holotype female is fossilized with her underside facing up. Portions of all but two of the legs are missing from the fossil. The carapace of the holotype is 9.31 by 6.83 millimetres (0.367 by 0.269 in) and the opisthosoma is 15.36 by 9.5 millimetres (0.605 by 0.374 in). The total body length is approximately 24.6 millimetres (0.97 in) while the front legs reach about 56.5 millimetres (2.22 in) in length. This puts M. jurassica females in the same size range as modern females of Nephila, and makes M. jurassica the largest described fossil spider.The tibia of the third leg features tufts of setae called gaiters, which are also found on the other three tibia. The feature of a gaitor on the third tibia is only found in modern Nephila and, according to the original authors of description of M. jurassica, its presence along with the large size indicated the species was part of the genus.
The allotopotype male has a body length of 16.54 millimetres (0.651 in) with elongated pedipalps.