Cyphon coarctatus
| Cyphon coarctatus | ||||||||||||
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Cyphon coarctatus , female |
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| Scientific name | ||||||||||||
| Cyphon coarctatus | ||||||||||||
| Paykull , 1799 |
Cyphon coarctatus is a beetle in the Scirtidae family (formerly Helodidae). The genus Cyphon is represented in Europe with 33 species . In Central Europe 13 types are distinguished. The Encyclopedia of Life names over 230 species. Worldwide, however, over 500 species are suspected to be in collections, most of which have not yet been identified or have been identified incorrectly. The genus is most likely not monophyletic . A later split is likely, a distinction is already made between " Cyphon in the narrower sense" and " Cyphon in the broader sense". Cyphon coarctatus is the type of the genus Cyphon .
The differences in the external characteristics between the species are not very clear, so that a genital examination must be carried out for a reliable determination . In males, the dorsal and ventral plates of the aedeagus are examined and the shape of the ninth sternite is used. In the female one examines the prehensor, an organ used to grasp the spermatophore .
Notes on the name
The genus Cyphon was established by Paykull in 1799 in the 2nd volume of his Fauna Svecica (Fauna of Sweden) and classified between the genera Atopa (today Dascillus ) and Cistela Fabricius (today dissolved). The species Cyphon coarctatus has been described in the same place . The ten-word short Latin description of the species contains the phrase Thorace antice coarctato (with a narrowed front edge of the chest). This explains the species name coarctatus (Latin coarctātus, narrowed). Paykull gave no explanation for the name of the genus Cyphon , according to Schenkling it is from Altgr. κύφων kyphon, yoke, Krummholz, derived and also relates to the shape of the pronotum (Fig. 4).
  
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| Fig. 1 different views | |
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| Fig. 2: Outline of pronotum | Fig. 3: Puncturing head |
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| Fig. 4: Hind tarsus | |
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Fig. 6: Prehensor of the female , left pocket without central part (similar to the closure of a safety pin), right central part (plate) dissected out; (Microscope image, transmitted light, both parts on the same scale) |
| Fig. 5: Aedeagus, spatial image (1912) c: hook (lat. Camur) ej: ejactulatory duct, mo: median orifice |
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Description of the beetle
The beetle reaches a length of 3.5 to four millimeters. The color varies from uniformly reddish brown to black, or the elytra are darker or occasionally lighter than the head and pronotum. The body is oval to elongated. The top is disordered and dotted about equally densely . The puncture is on the wing covers coarsest, on the head and almost as roughly the pronotum fine something.
The head (Fig. 3) is carried lowered. The head shield is set off in a line from the forehead. The eyes are large and lateral. The eleven-part antennae are turned in front of the eyes, the pits are closer together than the eyes. The antennae are thread-like, the first three links yellow, the following ones darker and increasingly hairy. The first antenna segment is significantly thicker in the female than the following. The third antennae is significantly shorter in both sexes and, especially in the male, narrower than the second and fourth. From the fourth member onwards, the feeler members are fairly uniform. The head is clearly grained. The upper lip is large and wider than it is long. The upper jaws are asymmetrical, the right one sickle-shaped, the left one bears a central tooth. The jaw probes are four-parted with a small base part, the remaining parts are about the same length and the end part is long, egg-shaped and pointed at an angle. The small three-part lip buttons show an unusual construction. The second link is open in the shape of a bowl and clearly bristled at the tip. The end link is pivoted in front of the tip of the second link at an angle to the longitudinal axis of the same.
The pronotum (Fig. 2) is about three times as wide as it is long at the front, and about a quarter of the width at the base. The obtuse front angles of the pronotum protrude only a little, in between the front edge is set back and bulges forward in the middle. The pronotum base is curved slightly inward, in addition to the clear posterior angles. It is fine, but particularly clearly dotted on the sides.
The elytra in the male are more extensive and more roughly punctured than the pronotum. In the female they are slightly indented behind the label and in this area the dots are more dense than usual. In addition, the hair there is finer and sloping inwards. Three to four longitudinal ribs are more or less clearly pronounced.
The front and mid-chest are each elongated backwards (prosternal and mesosternal process). The mid-breast has an indentation on the front in the middle to accommodate the prosternal process. The legs are typical walking legs that allow rapid movement. Legs and rails are unreinforced. All tarsi are five-part. The fourth link is bilobed. The claw link of the hind tarsi is significantly shorter than the first four tarsal links together (Fig. 4).
A drawing of the male reproductive organ of the species was published as early as 1912 on the occasion of a lecture in which the anatomy of the male reproductive tract was compared in different beetles. Part of the genital tract is shown in three dimensions (Fig. 5). Today, however, it is customary to depict the ventral plate of the aedeagus and the dorsal roof-shaped piece of chitin that delimits the opening of the genital tract in a top view. The ventral plate ends in two large, claw-like hooks that open at the bottom. The dorsal chitin clasp, through the slit of which the spermatophore emerges (labeled mo in Fig. 5) , is roughly triangular with two broad thighs with bristles and a plate similar to the shoulder blade at the tip. In addition to the dorsal and ventral plates, the ninth sternite and occasionally the 8th and 9th tergite are used to identify the males. The female has an organ for recording the spermatophore, the prehensor. Its sclerotized parts form a pocket that closely resembles the closure of a safety pin (Fig. 6 left). In this pocket there is a plate roughened by small pins (Fig. 6 right).
biology
The larvae develop in the water. The adults can be found on the edges of standing water, in damp forests and on damp forest edges, on swampy meadows or in floodplains. Strongly acidic moor waters are avoided. In the Netherlands were Imagines observed from March to October, eggs bearing females in June, very rare even in May.
distribution
The species is distributed from Spain and Italy to Norway , Sweden and Finland , but is absent in Portugal and Greece . In the west it reaches France , England and Ireland , to the southeast the occurrence is limited, for example no finds from Slovenia , Hungary and Bulgaria are known. But it occurs in Romania, European Russia , north to Karelia, and in the Caucasus region.
literature
- Heinz Joy, Karl Wilhelm Harde, Gustav Adolf Lohse: The beetles of Central Europe . tape 6 : Diversicornia . Spectrum, Heidelberg 1979, ISBN 3-87263-027-X . P. 259
- Klaus Koch : The Beetles of Central Europe Ecology . 1st edition. tape 2 . Goecke & Evers, Krefeld 1989, ISBN 3-87263-040-7 . P. 113
Individual evidence
- ↑ a b Cyphon coarctatus in Fauna Europaea. Retrieved July 18, 2014
- ^ Cyphon at Fauna Europaea. Retrieved July 18, 2014
- ↑ Genus Cyphon in Coleo-net [1]
- ↑ Encyclopedia of Life [2]
- ^ Bernhard Klausnitzer: Insecta: Coleoptera: Scirtidae Spektrum Akademischer Verlag Heidelberg 2009, ISBN 978-3-8274-1074-0 Preview in the Google book search, Typus von Cyphon p. 241
- ↑ Gustav Paykull: Fauna Svecica Upsala 1797–1800 p. 117 (Tomus II) Species description p.114 (2nd volume) Description of the genus
- ↑ Sigmund Schenkling: Explanation of the scientific beetle names (species)
- ↑ Sigmund Schenkling: Explanation of the scientific beetle names (genus) in detail in the 2nd edition 1922 .
- ↑ a b D. Sharp, F.Muir: The comparitive anatomy of the male genital tube in Coleoptera in Transactions of the Entomological Society of London for the year 1912 London 1912 - 1913 p. 544.Description on page 544 Figure panel LXXI, Fig. 188
- ↑ a b Dorsal and ventral plate of the Aedoeagus, images from coleo-net as drawings and photos
- ↑ JT Wiebes & A. Wiebes-Rijks (1964): De Nederlandse soorten van het genus Cyphon Paykull (Coleoptera, Helodidae). Zoological Bijdragen 7: 3-16.
- ^ Bernhard Klausnitzer: On the knowledge of the Scirtidae (Coleoptera) of Greece (91st contribution on the knowledge of the Scirtidae). In: Stapfia. Volume 55. Linz 1998, pp. 567-576, PDF on ZOBODAT
- ↑ U. Hannappel & HF Paulus (1997): Knowledge of larvae and distribution of the Scirtidae in the western Palearctic with a key to identify European larvae of the genus Elodes LATREILLE, 1796. Koleopterologische Rundschau 67: 225-251.
