Nemonychidae

Doydirhynchus austriacus

The Nemonychidae are a family of weevils ( in the broader sense, the superfamily Curculionoidea ). Almost all of the oldest fossil found weevils from the Jura belong to this family. The extant species form a species-poor relict group, they are considered the most primitive surviving weevils. The family includes 75 living ( extant ) species in 25 genera and at least 56 known fossil species. In Central Europe, three species.

Features

The family includes quite small, inconspicuous, yellow-brown to black colored beetle with relatively uniform body shape. It is usually around elongated animals with parallel-sided elytra, a laterally weakly rounded pronotum slightly narrower than the elytra and an outstretched head with hemispherical head contour from the above compound eyes. The animals are delicately built as compared to other Curculionoidea and weakly sclerotized. Almost all types carry a dense, fine hair which is often colored white. Shed or shed hairs that are characteristic of many Weevils families do not occur. The eponymous for the weevil snout (or rostrum ) is modified very diverse, there are species with a very short, others long and thin, curved trunk before, sometimes the trunk is towards the tip slightly widened ( expanded ). Also the sensors may be turned in to the base, in the middle or near the top of the spout. As a major exception within the weevil (outside of bark beetles in the broader sense ) is in the family without even a kind of trunk before: Brarus Mystus from Brazil, which can thereby confused at first glance with a beetle.

The Nemonychidae belong to the primitive grouping of the weevil with straight, not geknieten sensors ( " Orthoceri " ), the eleven-membered sensors have only a weak remote, loosely structured tripartite sensor leg on. The family also has other numerous ancient plesiomorphic features that make them within the weevil. Thus, the labrum is not fused with the clypeus, but freely designed. The Maxillarpalpen are mehrgliedrig and mobile. In contrast to most other lines of weevils (only together with the Belidae and some Attelabidae ) have the elytra or elytra inside no second edge; therefore it is not possible for them as the representatives of the other lines rigidly couple the elytra to the abdomen and to take such a well-protected, armored protection form. The abdomen is divided accordingly loose, the ventral sclerites are not fused together for better protection. The most important autapomorphy is the shape of the ninth Tergits on the abdomen of the male. This is converted to a unsklerotisierten, but heavily pigmented band which rests the ninth sternite.

Larvae

The larvae of Nemonychidae are small, less than ten millimeters long and lean animals. Just as the imagos have the larvae lots of original, plesiomorphic features compared to the other lines of the weevil characterize the family. Thus only in the genus Nemonyx still larvae with three - or four-membered legs with a claw at the end, before, during typical weevil larvae are legless. The larva has a single functional larval eye ( Stemma or Ocularium ) and malfunctioning rudiments of two or three more.

Peculiar features ( autapomorphies ) of Nemonychidenlarven are: At the head capsule, the suture between clypeus and frons is gone, the frons is extended forward and forms a so-called Pseudoclypeus from. In addition, a characteristic his gum line is at the basal part of mandibles, in the area of the occlusal surface or Mola available. A striking feature of the larvae of the subfamily Rhinorhynchinae is that they do not crawl on a flat surface with the ventral side, but with the back side facing down.

Way of life

Nemonychidae are - linked to Conifer - with two exceptions. The larvae are specialized pollen eaters, they live in the strobili, the male, peg-like " catkins " that produce for the wind-pollinated conifers typical, large amounts of pollen. The female lays usually be egg on the pollen sacs (or microsporangia ) in the strobili, as they begin to open, but the pollen grains are still immature. The ovipositor of the female is soft and unsklerotisiert and unable to pierce hard tissue. The larvae eat the pollen grains, they are very mobile and migrate, if necessary, between various male kitten back and forth. Due to the highly nutritious feed the larval development is extremely rapid, all larval stages are typically ( often in two or three weeks) go through in ten days. The mature larva can fall to the ground, burrows just under the leaf litter, a little doll chamber.

The further development is complex in many ways. Part of the larvae can pupate and then hatch immediately pupa after about three weeks. These Imagines hibernate and are eight months and more active. You must ingest food during this time. To the extent known, the imagines all kinds of either pollen or plant juices of sweet feed. A Befressen of leaves or needles of their host species was not observed in any case. Another part of the larvae remain in the chamber and overwintered pupae in the soil. They come after one, in some cases, partially only after two years into the open if and only if the immediately transformed imagos hatch. This behavior is interpreted as insurance against unfavorable, food poor years.

Almost all Nemonychidae are very host specific to a conifer genus, very often only one kind, the species of the front on the northern hemisphere ( Palearctic and Nearctic ) widespread subfamily Cimberidinae live on pine plants, all Central European ( Western Palaearctic ) species on pines ( genus Pinus ). Living in South America and in Western Australia and New Guinea Rhinorhynchinae occur at Araukariengewächsen ( Araucaria and kauri trees, not to Wollemia ) and podocarps, the genus Atopomacer that occurs in Central and North America, is probably secondary, transferred to Pinus.

As an exception, in the family, there are two kinship groups that live on angiosperms. All species of the subfamily Nemonychinae are specialists in the field larkspurs ( genus Consolida ), a kind of larkspurs ( Delphinium ), both of which belong to the Ranunculaceae. The two related genera Rhynchitomacer and Stenomacer live on sham Book ( genus Nothofagus, fagales ); but only in South America, although the genus in Australia and the surrounding islands occurs and here is even richer in species. All species are monophagous on a single Nothofagus species, although usually more of this occur together in a forest. Both the book -like as well as the Ranunculus belong to the basal lines of angiosperms.

Taxonomy and systematics

The taxonomy of the family is confused. The name formerly often used Rhinomaceridae is invalid because the name of the type genus had been awarded multiple times for two unspecified related genera. In his later importance he goes back to Fabricius. The type species of its genus Rhinomacer however, has been described with a different generic name earlier. The later entomologists aggravated with their interpretations of this situation, the chaos and created several non- legitimate alternative name. The actual opposite the name of " Cimberididae " younger Nemonychidae name is the International Commission on Zoological Nomenclature has been submitted in the interest of nomenclatural stability as a preservative to name.

The majority of scientists sees the family Anthribidae (or Breitrüssler ) as the sister group of the Nemonychidae. From earlier entomologists they were even temporarily considered as subfamily of Anthribidae. It seems still possible that the Nemonychidae are to settle within the Anthribidae, so this against them would be paraphyletic. Another possibility would be that the Nemonychidae isolated and a sister group of the remaining weevils were put together. An important difference between Nemonychidae and Anthribidae is the training of the legs. These contribute to Nemonychidae to the rails ( tibiae ) spurs that are missing the Anthribidae.

The recent Nemonychidae are usually divided into three subfamilies:

• Subfamily Nemonychinae. The only genus Nemonyx. Four species in the Western Palearctic, east to Kazakhstan, south to North Africa ( north of the Sahara ). In Central Europe, a kind of Nemonyx lepturoides

• Doydirhynchus austriacus
• Cimberis attelaboides (synonym: Rhinomacer attelaboides )

Fossils and Evolution

The oldest fossil Nemonychidae date from the Jurassic, they are among the oldest fossil weevils at all. Most of the fossil deposit Karatau ( today's spelling Qaratau ) were found in Kazakhstan. Other finds are from the Santana formation in Brazil and the Jehol Biota of China .. While they were still present in the chalk in some finds, until recently, from the Tertiary no longer Fund was known until 2010 but at least one type in Baltic amber has been described.

The assignment of numerous fossil weevil is still controversial. As the family Nemonychidae is mainly characterized by plesiomorphic features and the few autapomorphies can be obtained fossil hardly the assignment is so speculative, the older the fossils. It is quite likely that the superfamily of forms derived that may have seen the recent Nemonychidae extremely similar. Particularly controversial is as Eobelinae (or Eobelidae ) designated forms or kinship group. This is considered by many researchers as a subfamily of Nemonychidae, others see them as separate therefrom family who are close to the recent Belidae.

One argument for the antiquity of Nemonychidae is also their binding to conifers as host plants. Since the angiosperms are probably not much older than the Lower Cretaceous, the family Nemonychidae is probably older than this. It is believed that, it is a relict group that has survived from the root set today weevil. Your successful relatives who went over to angiosperms, would therefore can form thousands of new species, while they remained almost unchanged ..