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Raphidioptera

(Order)

Overview

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Snakeflies are a group of insects in the order Raphidioptera, consisting of about 210 extant species.1] Together with the Megaloptera they were formerly placed within the Neuroptera, but now these two are generally regarded as separate orders.

Snakeflies are predatory, both as adults and larvae. They can be quite common throughout temperate Europe and Asia, but in North America occur exclusively in the Western United States, namely in the Rocky Mountains and westward, including the southwestern deserts.

Anatomy and life cycle

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Adult snakeflies are characterized by having an elongate prothorax but no modification of the forelegs (as in Mantispidae). They have strong and relatively unspecialised mouthparts, and large compound eyes. Some species also have ocelli. The females typically have a long ovipositor, which the y use to deposit their eggs into crevices in bark or rotting wood. The wings are similar in size, with a primitive venation pattern, and a thickened costal margin (or "pterostigma").[2]

The larvae have large heads with projecting mandibles. The head and the first segment of the thorax are sclerotised, but the rest of the body is soft and fleshy. They have three pairs of true legs, but no prolegs. However, they do possess an adhesive organ on the abdomen, with which they can fasten themselves to vertical surfaces.[2]

The final larval instar creates a cell in which the insect pupates. However, they do not create a cocoon, and the pupa is fully capable of movement, and often leaves its cell for another location before the adult emerges. The larvae can take up to two years to develop.[2]

Systematics

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Distinguishing taxonomic features

The morphological characteristics which distinguish the order Raphidioptera from other insect orders are as follows :[3]

Taxonomy

The Megaloptera, Neuroptera (in the modern sense) and Raphidioptera are very closely related, forming the group Neuropterida. This is either placed at superorder rank, with the Endopterygota - of which they are part - becoming an unranked clade above it, or the Endopterygota are maintained as a superorder, with an unranked Neuropterida being a part of them. Within the endopterygotes, the closest living relatives of Neuropterida are the beetles.

The two extant families of snakeflies are the Raphidiidae and Inocelliidae. In addition, there are four extinct families known only from fossils.[4] Almost all known snakeflies belong to the suborder Raphidiomorpha.[4] The exception being the Jurassic family Priscaenigmatidae, placed in suborder Priscaenigmatomorpha.[4]

Extinct snakeflies are known from fossils dating from the Lower Jurassic to the Miocene.[4]

Raphidioptera as grouped according to Engel 2002:[4]

Order Raphidioptera

Footnotes

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  1. ^ Jepson, J.E.; Jarzembowski, E.A. (2008). "Two new species of snakefly (Insecta:Raphidioptera) from the Lower Cretaceous of England and Spain with a review of other fossil raphidiopterans from the Jurassic/Cretaceous transition". Alavesia 2: 193?201. http://fossilinsects.net/pdfs/Jepson_Jarzembowski_2008_Alavesia_SnakeflyLowerCretaceousEnglandSpain.pdf. 
  2. ^ a b c Hoell, H.V., Doyen, J.T. & Purcell, A.H. (1998). Introduction to Insect Biology and Diversity, 2nd ed.. Oxford University Press. pp. 445?446. ISBN 0-19-510033-6. 
  3. ^ Gillot, C. (1995). "Raphiodioptera". Entomology (2 ed.). pp. 293?295. ISBN 9780306449673. http://books.google.co.in/books?id=DrTKxvZq_IcC&lpg=PR1&pg=PA293#v=onepage&q&f=false. Retrieved 14 November 2010. 
  4. ^ a b c d e Engel, M.S. (2002). "The Smallest Snakefly(Raphidioptera: Mesoraphidiidae): A New Species in Cretaceous Amber from Myanmar, with a Catalog of Fossil Snakeflies". American Museum Novitates 3363: 1?22. hdl:2246/2852. 
>Snakeflies are a group of insects in the order Raphidioptera, consisting of about 210 extant species.1] Together with the Megaloptera they were formerly placed within the Neuroptera, but now these two are generally regarded as separate orders.

Snakeflies are predatory, both as adults and larvae. They can be quite common throughout temperate Europe and Asia, but in North America occur exclusively in the Western United States, namely in the Rocky Mountains and westward, including the southwestern deserts.

Anatomy and life cycle

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Adult snakeflies are characterized by having an elongate prothorax but no modification of the forelegs (as in Mantispidae). They have strong and relatively unspecialised mouthparts, and large compound eyes. Some species also have ocelli. The females typically have a long ovipositor, which they use to deposit their eggs into crevices in bark or rotting wood. The wings are similar in size, with a primitive venation pattern, and a thickened costal margin (or "pterostigma").[2]

The larvae have large heads with projecting mandibles. The head and the first segment of the thorax are sclerotised, but the rest of the body is soft and fleshy. They have three pairs of true legs, but no prolegs. However, they do possess an adhesive organ on the abdomen, with which they can fasten themselves to vertical surfaces.[2]

The final larval instar creates a cell in which the insect pupates. However, they do not create a cocoon, and the pupa is fully capable of movement, and often leaves its cell for another location before the adult emerges. The larvae can take up to two years to develop.[2]

Systematics

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Distinguishing taxonomic features

The morphological characteristics which distinguish the order Raphidioptera from other insect orders are as follows :[3]

Taxonomy

The Megaloptera, Neuroptera (in the modern sense) and Raphidioptera are very closely related, forming the group Neuropterida. This is either placed at superorder rank, with the Endopterygota - of which they are part - becoming an unranked clade above it, or the Endopterygota are maintained as a superorder, with an unranked Neuropterida being a part of them. Within the endopterygotes, the closest living relatives of Neuropterida are the beetles.

The two extant families of snakeflies are the Raphidiidae and Inocelliidae. In addition, there are four extinct families known only from fossils.[4] Almost all known snakeflies belong to the suborder Raphidiomorpha.[4] The exception being the Jurassic family Priscaenigmatidae, placed in suborder Priscaenigmatomorpha.[4]

Extinct snakeflies are known from fossils dating from the Lower Jurassic to the Miocene.[4]

Raphidioptera as grouped according to Engel 2002:[4]

Order Raphidioptera

Footnotes

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  1. ^ Jepson, J.E.; Jarzembowski, E.A. (2008). "Two new species of snakefly (Insecta:Raphidioptera) from the Lower Cretaceous of England and Spain with a review of other fossil raphidiopterans from the Jurassic/Cretaceous transition". Alavesia 2: 193?201. http://fossilinsects.net/pdfs/Jepson_Jarzembowski_2008_Alavesia_SnakeflyLowerCretaceousEnglandSpain.pdf. 
  2. ^ a b c Hoell, H.V., Doyen, J.T. & Purcell, A.H. (1998). Introduction to Insect Biology and Diversity, 2nd ed.. Oxford University Press. pp. 445?446. ISBN 0-19-510033-6. 
  3. ^ Gillot, C. (1995). "Raphiodioptera". Entomology (2 ed.). pp. 293?295. ISBN 9780306449673. http://books.google.co.in/books?id=DrTKxvZq_IcC&lpg=PR1&pg=PA293#v=onepage&q&f=false. Retrieved 14 November 2010. 
  4. ^ a b c d e Engel, M.S. (2002). "The Smallest Snakefly(Raphidioptera: Mesoraphidiidae): A New Species in Cretaceous Amber from Myanmar, with a Catalog of Fossil Snakeflies". American Museum Novitates 3363: 1?22. hdl:2246/2852. 

References

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Taxonomy

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The Order Raphidioptera is further organized into finer groupings including:

Families

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Alloraphidiidae

[more]

Baissopteridae

[more]

Inocelliidae

Inocelliidae is a small family of snakeflies containing 8 genera of which one is known only from fossils. They are commonly known as inocelliid snakeflies. The largest known species is Fibla carpenteri known from fossils found in baltic amber. [more]

Mesoraphidiidae

[more]

Priscaenigmatidae

[more]

Raphidiidae

[more]

At least 216 species and subspecies belong to the Family Raphidiidae.

More info about the Family Raphidiidae may be found here.

References

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Footnotes

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  1. ^ a b c Hoell, H.V., Doyen, J.T. & Purcell, A.H. (1998). Introduction to Insect Biology and Diversity, 2nd ed.. Oxford University Press. pp. 445-446. ISBN 0-19-510033-6. 
  2. ^ Also called "Neuropteroidea", though the ending "-oidea" is normally used for superfamilies. See references in Haaramo (2008).
  3. ^ a b See references in Haaramo (2008)

Sources

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Last Revised: August 24, 2012
2012/08/24 13:14:27