Scourge Scorpions

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Scourge Scorpions
Typopeltis sp.

Typopeltis sp.

Systematics
without rank: Primordial mouths (protostomia)
Over trunk : Molting animals (Ecdysozoa)
Trunk : Arthropod (arthropoda)
Sub-stem : Jawbearers (Chelicerata)
Class : Arachnids (arachnida)
Order : Scourge Scorpions
Scientific name
Uropygi
Thorell , 1883
Submissions

The scourge scorpions (Uropygi) are an order of the arachnids (Arachnida) and thus belong to the jaw-claw carriers (Chelicerata). Around 180 species are known worldwide , which can be assigned to two very different sub-orders. The dwarf scourge scorpions (Schizomida) reach body lengths of a maximum of 18 mm, in contrast, the representatives of the Thelyphonida are up to 75 mm long (without a tail). The animals inhabit the tropics and subtropics.

Construction of the scourge scorpions

The body structure of the scourge scorpions is reminiscent of that of the scorpions , the tail-like end part of the abdomen consists of only three segments and ends in a segmented tail appendage ( flagellum ). As with the scorpions, the pedipalps have been transformed into mighty fangs and provided with scissors. The first pair of legs is conspicuous, which, like the flagellum spiders , is laid out as long tactile organs with an increased number of leg links. Accordingly, the animals walk on only 3 pairs of legs like the six-footed . The jaw claws ( chelicerae ) are two-part and are used to tear up prey.

Large defensive glands open out on both sides of the flagellum, with which the animals can spray a defensive secretion . Due to the mobility of the abdomen, it comes out as a targeted beam. The giant scourge scorpion ( Mastigoproctus giganteus ) consists of 84% acetic acid , 5% caprylic acid and 11% water. These animals can inject the secretion up to 80 cm and it stings in the eyes and on the mucous membranes if you are hit by it.

Reproduction and development

As with the scorpions, the female is pulled by the male over a previously deposited sperm packet ( spermatophore ). In doing so, however, the female grabs either the abdomen (in the thelyphonidae) or the button-like thickened flagellum (in the schizomidae) of the male and can be pulled over the sperm packet. The males of the thelyphonida often help with their specially redesigned pedipalps by literally stuffing the sperm packet into the female sexual opening and then tearing it open.

In an underground brood chamber, the female lays the eggs in a specially constructed brood sac that she carries around her abdomen. The Pränymphen keep after hatching with release tab on the legs on the abdomen of the nut, then they let go. Four more moults follow until the animals are sexually mature (in Mastigoproctus two to four years). Each molt takes place in a specially dug cave in which the animals stay for several months.

Systematics of the scourge scorpions

The scourge scorpions are divided into two morphologically very different suborders, which are referred to as thelyphonida and schizomida (also dwarf scourge scorpions ).

Thelyphonida

In the thelyphonida, an undivided blanket covers the entire front body. Compared to the representatives of the schizomida, these animals are very large with a maximum body length of 75 mm. The pedipalps are extremely large and armed with thorns and large scissors. The flagellum is long and multi-limbed. The representatives of this group live mainly in the rainforests of the Indo-Pacific region and American region, one species lives in Africa . The giant scourge scorpion ( Mastigoproctus giganteus ) lives mainly in the southern states of the USA .

Dwarf Scorpion Scorpions (Schizomida)

These animals are very small with a maximum body length of 18 mm. They live mainly in the litter or in caves . There are about 350 recent species in the two families Protoschizomidae and Hubbardiinae, the former only including the two genera Protoschizomus and Agastoschizomus . The remaining 63 genera belong to the two subfamilies of the Hubbardiidae family: Hubbardiinae (62 genera) and Megaschizominae (1 genus). Like all Chelicerata, schizomids have six pairs of extremities on the prosoma: One pair each of Chelicerae, Pedipalps, and 4 pairs of legs, whereby the foremost pair is usually significantly elongated. This is used less for locomotion than for feeling the environment, since today all but four schizomids are eyeless. However, there are many types with light-sensitive spots around the eyes. The prosoma is divided into several back plates: the propeltidium, which covers about 70-80% of the prosoma, and, followed by a pair of very small plates that are clearly separated from each other, the mesopeltidia. Behind it lies a pair of somewhat larger plates (metapeltidia), which, depending on the genus, are either clearly separated from one another, separated by a thin, visible suture or not separated at all. The pedipalps are slender and without scissors. In some species, sexual dimorphism occurs within a species or depending on gender, with the pedipalps being greatly elongated, but less powerful. The chelicerae have a movable and a fixed element. The opisthosoma consists of twelve segments and is protected both dorsally and ventrally by stable sternites or tergites. The flagellum (which attaches to the last segment of the opisthosoma) is the most important diagnostic feature for differentiating the sex of schizomids. In female animals it is narrow and stem-shaped, from one to a maximum of five annuli. In males, the flagellum is thickened and can have various shapes, e.g. B. plate-shaped, spade-shaped, shovel-like, etc. Another important distinguishing feature of the schizomids is a thorn-like outgrowth on the coxa of the second pair of legs. To determine the genus or species, the number and arrangement of the setae on the chelicerae, pedipalps, at the base of the propeltidium, on the propeltidium, on the sternites, on the opisthosoma and on the flagellum are mainly used today. The pygmy scourge scorpions are native to all tropical regions of the world, with particularly high diversity being documented for Australia (54), Cuba (49) and Mexico (46). Some species have been regularly detected in heated greenhouses in Europe since the 19th century.

Fossil evidence of this group is rare because of its size and poor fossilization potential. Fossils have been described from the Pliocene of Arizona (Petrunkevitch 1945, Pierce 1950), the Miocene of Dominican amber (Krüger and Dunlop 2010) and the Oligocene of China (Lin et al. 1988). A male schizomid ( Mesozomus groehni ) from the Upper Cretaceous Period ( Birmit ) has also been known since 2019 .

Individual evidence

  1. Stanislav Korenko, Mark Harvey, Stano Pekár (2010): Stenochrus portoricensis new to the Czech Republic. Arachnological Notes 38: 1-3. ( Online ; PDF; 193 kB)
  2. ^ Sandro P. Müller, Jason A. Dunlop, Ulrich Kotthoff, Jörg U. Hammel, Danilo Harms (2020): The oldest short-tailed whipscorpion (Schizomida): a new genus and species from the Upper Cretaceous amber of northern Myanmar. Cretaceous Research 106. Article 104227. doi : 10.1016 / j.cretres.2019.104227

Web links

Commons : Scourge Scorpions  - Collection of images, videos and audio files