Protura

Protura
Protura
Acerentomon doderoi
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Hexapoda
Class: Entognatha
Order: Protura
Silvestri, 1907
Families [1]

Acerentomata

  • Hesperentomidae
  • Protentomidae
  • Acerentomidae

Eosentomata

  • Antelientomidae
  • Eosentomidae

Sinentomata

  • Fujientomidae
  • Sinentomidae

The Protura, or proturans, and sometimes nicknamed coneheads[2][3] are an order of hexapods previously regarded as insects, and sometimes treated as a class in their own right.[4] There is some evidence that the Protura are basal to all other hexapods,[5] although hexapods are increasingly thought to be polyphyletic.[6] They are very small (<2 mm long) soil-dwelling animals and are unique among hexapods for showing anamorphic development, whereby body segments are added during moults.[7] Szeptycki (2007) lists a total of 731 described species worldwide, in seven families, nearly 300 of which are contained in a single genus, Eosentomon.[1]

Contents

Morphology

Acerentomon species under stereo microscope

Proturans have no eyes, wings or antennae and lack pigmentation: they are usually white or pale brown. The sensory function of the antennae is fulfilled by the first of three pairs of five-segmented legs, which are held pointing forwards and have many tarsal sensilla and sensory hairs.[8] The head is conical, and bears two pseudoculi with unknown function. The body is elongate and cylindrical,[9] with a post-anal telson at the end. The mouthparts are entognathous (enclosed within the head capsule) and consist of thin mandibles and maxillae.[7] There are no cerci at the end of the abdomen, which gives the group their name, from the Greek proto- (meaning "first", in this case implying primitive), and ura, meaning "tail".[10] The first three abdominal segments bear limb-like appendages[8] called "styli".[10] The genitalia are internal and the genital opening lies between the eleventh segment and the telson of the adult.[8] Members of Eosentomoidea possess spiracles and a simple tracheal system while those in the Acerentomoidea lack these structures and perform gas exchange by diffusion.[8]

Ecology

Proturans live chiefly in soil, moss and leaf litter[7] of moist temperate forests[10] which are not too acidic,[11] but have also been found beneath rocks or under the bark of trees,[9] as well as in animal burrows.[8] They are generally restricted to the uppermost 10 centimetres (3.9 in),[11] but have been found as deep as 10 inches (250 mm).[12] Although they are sometimes considered uncommon,[10] they are probably often overlooked because of their small size,[9] and densities of over 90,000 individuals per square metre have been measured.[13]

The diet of proturans is uncertain, but they feed on mycorrhizal fungi, dead Acari, and mushroom powder in culture,[8] and are thought to feed on decaying vegetable matter and fungi in the wild.[10][9] The styliform mouthparts suggest that Protura are fluid feeders and there is evidence that some species suck out the contents of fungal hyphae.[11]

Proturans which live near the soil surface generally have one generation per year and have longer legs while those that live deeper have shorter legs and reproduce less seasonally, although there are also migratory species which move to deeper layers for the winter and shallower layers for the summer.[11]

Development

The larva has nine abdominal segments, but the number increases through moulting until the full adult number of twelve is reached. Further moults may occur, but do not involve any additional body segments,[10] and it is not known whether the adults continue to moult throughout their lives.[8] Eggs have only been observed in a few species.[8] Five developmental stages follow: the prelarva hatches from the egg and has only weakly developed mouthparts and nine abdominal segments; larva I follows and has fully developed mouthparts; larva II has ten adbominal segments; maturus junior has twelve abdominal segments and is followed by the adult.[8] The family Acerentomidae differs in having an extra pre-imago stage, with partially developed genitalia, between the maturus junior and the adult.[8]

History

Proturans were first discovered in the early twentieth century, when Filippo Silvestri and Antonio Berlese discovered the animals independently.[11] The first species to be described was Acerentomon doderoi, published in 1907 by Silvestri,[8] based on material from near Syracuse, New York.[10]

References

  1. ^ a b Andrzej Szeptycki (2007). "Catalogue of the World Protura". http://www.isez.pan.krakow.pl/journals/azc_i/pdf/50B(1)/01.pdf. 
  2. ^ "Proturans / Coneheads". North Carolina State University College of Agriculture and Life Sciences. http://www.cals.ncsu.edu/course/ent425/compendium/protura.html. Retrieved July 30, 2008. 
  3. ^ "Order Protura - Coneheads". http://bugguide.net bugguide.net, hosted by Iowa State University Department of Entomology. http://bugguide.net/node/view/99913/bgpage. Retrieved July 30, 2008. 
  4. ^ Charles S. Henry (2005). "Insect phylogeny". University of Connecticut. http://www.eeb.uconn.edu/Courses/Eeb477/. 
  5. ^ Ryuichiro Machida (2006). "Evidence from embryology for reconstructing the relationships of hexapod basal clades". http://globiz.sachsen.de/snsd/publikationen/ArthropodSystematicsPhylogeny/ASP_64_1/ASP_64_1_Machida_95-104.pdf. 
  6. ^ Charles E Cook, Qiaoyun Yue & Michael Akam (2005). "Mitochondrial genomes suggest that hexapods and crustaceans are mutually paraphyletic". Proceedings of the Royal Society B 272 (1569): 1295–1304. doi:10.1098/rspb.2004.3042. PMC 1564108. PMID 16024395. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1564108. 
  7. ^ a b c P. J. Gullan & P. S. Cranston (1994). The insects: an outline of entomology. Chapman and Hall. ISBN 0-412-49360-8. 
  8. ^ a b c d e f g h i j k Christopher Tipping (2004). "Proturans". University of Florida. http://entomology.ifas.ufl.edu/creatures/misc/proturans.htm. 
  9. ^ a b c d "Protura". CSIRO. http://www.ento.csiro.au/education/hexapods/protura.html. 
  10. ^ a b c d e f g John R. Meyer (March 5, 2005). "Protura". North Carolina State University. http://www.cals.ncsu.edu/course/ent425/compendium/protura.html. 
  11. ^ a b c d e "Gordon's Protura Page". November 11, 2005. http://www.earthlife.net/insects/protura.html. 
  12. ^ "Protura". Tree of Life Web Project. January 1, 2002. http://tolweb.org/Protura/8203/2002.01.01. 
  13. ^ J. Krauß & W. Funke (1999). "Extraordinary high density of Protura in a windfall area of young spruce plants". Pedobiologia 43: 44–46. 

External links

Cercophonius squama.jpg Arthropods portal

Wikimedia Foundation. 2010.

Игры ⚽ Поможем написать реферат

Look at other dictionaries:

  • Protura — Saltar a navegación, búsqueda ? Protura Acerentomon …   Wikipedia Español

  • protură — PROTÚRĂ, proture, s.f. (La pl.) Ordin de insecte inferioare, fără aripi, antene şi ochi, cu rudimente de picioare şi cu armătură bucală pentru supt şi mestecat; (şi la sg.) insectă din acest ordin. – Din fr. protoures. Trimis de oprocopiuc, 23.04 …   Dicționar Român

  • Protura — Protura, Beintastler, Unterklasse der ⇒ Apterygota; 0,5–2 mm lang; Bodenbewohner; ohne Antennen und Augen; tasterartiges erstes Beinpaar …   Deutsch wörterbuch der biologie

  • Protura — Protura …   Wikipédia en Français

  • Protura — Beintastler Beintastler (Protura) Systematik Überstamm: Häutungstiere (Ecdysozoa) Stamm …   Deutsch Wikipedia

  • Protura — Eosentomidae Sinentomidae Acerentomidae Protentomidae Los proturos (latín Protura) son pequeños animales artrópodos que forman una clase dentro de la superclase hexápodos (Hexapoda), lo que les sitúa muy próximos a los insectos verdaderos (clase… …   Enciclopedia Universal

  • Protura — noun minute wingless arthropods: telsontails • Syn: ↑order Protura • Hypernyms: ↑animal order • Member Holonyms: ↑Insecta, ↑class Insecta, ↑Hexapoda, ↑class Hexapoda …   Useful english dictionary

  • Protura — …   Википедия

  • protura — pro·tu·ra …   English syllables

  • Отряд Бессяжковые (Protura) —          Эти удивительные мелкие членистоногие, распространенные в странах и с умеренным, и с тропическим климатом, были открыты совсем недавно только 50 лет тому назад знаменитым итальянским зоологом Ф. Сильвестри. Может возникнуть вопрос:… …   Биологическая энциклопедия

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”