Woodlice
Temporal range: ca.Carboniferouspresent, 300–0 Ma
Collage of woodlice.
Clockwise from top right: Ligia oceanica, Hemilepistus reaumuri, Platyarthrus hoffmannseggii and Schizidium tiberianum
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Malacostraca
Order: Isopoda
Suborder: Oniscidea
Latreille 1802[1]
Sections

A woodlouse (plural woodlice) is a crustacean from the monophyletic[2] suborder Oniscidea within the isopods. The first woodlice were marine isopods which are presumed to have colonised land in the Carboniferous.[3] They have many common names and although often referred to as 'terrestrial Isopods' some species live semiterrestrialy or have recolonised aquatic environments. Woodlice in the families Armadillidae, Armadillidiidae, Eubelidae, Tylidae and some other genera can roll up into an almost perfect sphere as a defensive mechanism, others have partial rolling ability but most cannot conglobate at all.

Woodlice have a basic morphology of a segmented, dorso-ventrally flattened body with 7 pairs of jointed legs, specialised appendages for respiration and like other peracarids, females carry fertilised eggs in their marsupium, through which they provide developing embryos with water, oxygen and nutrients. The immature young hatch as mancae and receive further maternal care in some species. Juveniles then go through a series of moults before reaching maturity.

While the broader phylogeny of the Oniscideans has not been settled, five Infraorders/Sections are agreed on with 3637 species validated in scientific literature in 2004[4] and 3710 species in 2014 out of an estimated total of 5000-7000 species extant worldwide.[5] Key adaptations to terrestrial life has led to a highly diverse set of animals; from the marine littoral zone and subterranean lakes to arid deserts and mountain slopes 4,725m above sea-level, woodlice have established themselves in most terrestrial biomes and represent the full range of transitional forms and behaviours for living on land.

Woodlice are widely studied in the contexts of evolutionary biology, behavioural ecology and nutrient cycling. They are popular as terrarium pets because of their varied colour and texture forms, conglobating ability and ease of care.

Anatomy

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The exoskeletons of woodlice are permeable as they lack the waxy coating found on other terrestrial arthropods, such as the insects. Marine isopods

Tagmata

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The bodies of woodlice are divided into three sections or tagma: Cephalon, Pereon and Pleon. The segments of the pereon and pleon are collectively called somites (body segments). Their dorsal plates are called tergites and their ventral plates are called sternites.

The appendages of woodlice may be biramous (branched) or uniramous (unbranched). The ramus (branch) which is furthest away from the woodlouse's central line of symmetry is termed the exopodite (external branch), while the ramus (branch) which closest to the woodlouse's centre is termed the endopodite (internal branch). Any part of the biramous appendage to which the exopodite and endopodite are attached to is termed the propodite.

Cephalon

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The cephalon, or head, is the anterior-most part of the body. It is derived from the five cephalic and first thoracic metameres of the ancestral Eumalacostraca.

When referring to Onicideans in the context of other crustaceans the term cephalothorax is used, as what would have been the first thoracic segment in other Isopods has fused to the head in woodlice.

It has the following pairs of appendages:

  • antennules (primary antennae) these are greatly reduced in all woodlice. They are tipped with aesthetascs and are used for olfaction. Their reduction in size is thought to make the harder to damage, in an encounter with a predator for example, thus acting as a reliable means of detecting moisture.[6]
  • antennae (secondary antennae) these consist of peduncle formed of five articles and end in a flagellum. The length and shape of the antennae are useful in identification as the flagellum, especially, varies considerably even between closely related species. These appendages a woodlouse's primary sensory organs, able to discern tactile and sensory cues. It has been shown that woodlice adapted to more terrestrial habitats have shorter and simpler flagella. The antennae of the supralittoral Ligia oceanica for example are two-thirds its body length while those of the fully terrestrial Helleria brevicornis are short and stubby.[6] Some woodlice, like P scaber use their antennae to right themselves if they are turned upside down.
  • mandibles
  • maxillules
  • maxillae
  • maxillipeds, are derived from 'leg' appendages of the erstwhile first thoracic metamere.

Woodlice also have either a pair of compound eyes, with a varied number of ommatidae and in various arrangements, or a set of ocelli arranged symmetrically on both sides of the cephalon. Some woodlice, like the Platyarthus species which live as commensals in ant nests and some troglobitic species have lost sight altogether.

Pereon

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The pereon (thorax) consists of seven pereonites (pereonal somites), each of which has a pair of uniramous (pereonal appendages). The pereopods are the woodlous's walking legs and consist of seven articles -

Manca are born with only six pairs of pereopods, the seventh pair only form after the first moult. In male, paired ventral copulatory papillae (occasionally a single cone) on ventral surface (sternite) of last (seventh) pereon segment (pereonite); transfers sperm to gonopods.
gonopore: In female reproductive system, opening of each oviduct to exterior; located on ventral surface (sternite) of fifth pereon segment (pereonite). epimera

Pleon

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The pleon (abdomen) consists of five pleonites (pleonal somites). The posterior-most segment is called the telson. Morphologically this segment was formed by the fusion of the erstwhile sixth pleonal somite with the telson, thus it is referred to as the pleotelson in context of other crustaceans.

Each pleonite has a pair of pleopods (pleonal appendages), which are biramous and flattened parallel to the ventral surface of the pleon... psuedotrachea, respiration.[7]

The telson also has a pair of appendages called the uropods. The size and shape of the uropods is varied but they are generally biramous, with distinct protopodite, exopodite and endopodite.

psuedotrachea
haemolymph
Male glands, hepatopancreas
tricorn, aesthetascs,

Book: S. Sutton (Auth.)- Woodlice - Pergamon Press (1972)

https://commons.wikimedia.org/wiki/File:FMIB_47699_Sturcture_of_the_Breathing_Organs_of_Porcellio_scaber.jpeg

https://commons.wikimedia.org/wiki/Category:The_British_Woodlice_(1906)

http://lanwebs.lander.edu/faculty/rsfox/invertebrates/armadillidium.html

http://lanwebs.lander.edu/faculty/rsfox/invertebrates/ligia.html

http://lanwebs.lander.edu/faculty/rsfox/invertebrates/armadillidium.html

https://research.nhm.org/glossary/all.html

http://www.gutenberg.org/files/43928/43928-h/43928-h.htm

https://archive.org/stream/britishwoodliceb00webb

https://archive.org/stream/bulletinunitedst541905unit

https://www.flickr.com/photos/internetarchivebookimages/14758874206/

https://www.flickr.com/photos/odonataman/10057865136

https://commons.wikimedia.org/wiki/File:Armadillo_officinalis_-_-_Print_-_Iconographia_Zoologica_-_Special_Collections_University_of_Amsterdam_-_UBAINV0274_006_03_0042.tif

http://nzslaters.massey.ac.nz/morphology.php

http://www.sylvanusservices.com/resources/Woodlice_Info.pdf

https://commons.wikimedia.org/wiki/File:Porcellio_olivieri_-_-_Print_-_Iconographia_Zoologica_-_Special_Collections_University_of_Amsterdam_-_UBAINV0274_098_08_0032.tif

Lifecycle

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wolbachia sex change

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DOI 10.1163/187498308X414724

Ecology

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soil formation, nutrient recycling

Diversity

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Woodlouse species diversity:

  • mainly terrestrial in damp habitats with cosmopolitan species well adapted to land such as A. vulgare, Oniscus asellus and Porcellio scaber
  • supralittoral species: ligia (sea slaters/rock lice) & tylos (https://www.sciencedirect.com/science/article/pii/S0065288108600620?via%3Dihub),
  • freshwater: macedonthens stankoi,
  • saltwater:Haloniscus searlei https://www.sciencedirect.com/science/article/pii/0010406X69900322,
  • high altitude: Protracheoniscus nivalis, up to 4725m in Ladakh (https://www.biodiversitylibrary.org/part/201022),
  • semi-arid Hemilepistus reaumuri, well known because of its highly developed social behavior. It occurs along the northern edge of the Sahara from Algeria to southern Israel, western Jordan, and the Syrian Desert. However, if we look for its closest relatives, we find them in western and central Asia. This means that Hemilepistus reaumuri came from the east and that the colonization of North Africa was a secondary event after the species had colonized the central Near East.
  • Helmut Schmalfuss (1998) THE TERRESTRIAL ISOPOD FAUNA OF THE CENTRAL NEAR EAST: COMPOSITION AND BIOGEOGRAPHY, Israel Journal of Zoology, 44:3-4, 263-271
  • Shachak, M. & Yair, Y. (1984) Population dynamics and the role of Hemilepistus reaumurii (Audouin & Savigny) in a desert ecosystem. Symposia of the Zoological Society of London, 53, 295–314
  • arid P. albinus is found far into real desert, i.e. Saharan sand seas; linsenmair 2007(DOI:10.1093/acprof:oso/9780195179927.003.0016),
  • cave dwelling: various Trichoniscidae species such as Titanethes albus & Haplophthalmus danicus. Also the only two species in section Microcheta, Mesoniscus alpicolus and Mesoniscus graniger.
  • commensalists in ant nests Plathyarthrus spp.,
  • mainly detritivores but tylos latreillei is active carnivore [citation needed],
  • size smallest?,
  • size largest upto 55 mm Tylos granulatus
  • Geographical distribution from Taiga (https://zookeys.pensoft.net/articles.php?id=2538) to sub-Antarctic (https://doi.org/10.1007/s00300-002-0420-9)
  • Mediterranean coastal regions have most recorded diversity (because of European research and ), coastal regions in general have more diversity

Feeding

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Predation

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Other Behaviour

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conglobation

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  • the following families are rollers: Armadillidae, Eubelidae, Armadillidiidae, Sphaeroniscidae, and Tylidae (hornburg review)
  • avoid predation, prevent water loss

Origins and taxonomy

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According to Schmallfuss(http://www.oniscidea-catalog.naturkundemuseum-bw.de/Cat_terr_isop.pdf) these five taxa below are widely recognised but their phylogeny is still debated, so I think it's best to avoid phylogenetic trees or mentions of other uncertain taxa like Holoverticata, Tylomorpha, Orthogonopoda, Ligiamorpha etc.

Diplocheta (1 family - Ligiidae)
Tylida (1 family - Tylidae)
Microcheta (1 family - Mesoniscidae)
Synocheta (5 families - Schoebliidae, Styloniscidae, Titanidae, Trichoniscidae, Tunanoniscidae)
Crinocheta (26 families- Agnaridae, Alloniscidae, Armadillidae, Armadillidiidae, Balloniscidae, Bathytropidae, Berytoniscidae, Bisilvestriidae, Cylisticidae, Delatorreidae, Detonidae, Dubioniscidae, Eubelidae, Halophilosciidae, Hekelidae, IIrmaosidae, Olibrinidae, Oniscidae, Philosciidae, Platyarthridae, Porcellionidae, Pudeoniscidae, Pudeoniscidae, Rhyscotidae, Scleropactidae, Scyphacidae, Spelaeoniscidae, Sphaeroniscidae, Stenoniscidae, Tendosphaeridae, Trachelipodidae) He lists 31 families though

The earliest woodlice fossils date to the cretaceaous but common ancestor in Carboniferous... woddlice don't fossilise well

common names/cultural/ human interactions

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Woodlice neither eat live wood/dead wood(but eat rotting wood) nor are parasitic...

  • Common names

Common names for woodlice vary throughout the English-speaking world. A number of local names make reference to conglobation, others make comparisons to a pig, others relate to coastal habitat of family ligiidae. Ligiidae names: rock lice, sea slaters, wharf roaches, sea roaches, rock slaters, quay louse

Local names for common cosmopolitian species include: From existing article

  • As medicine:

Early mentions of hoglice(confused distintction between pill millipedes and pill woodlice) as medicine

Latreille's mention of woodlice as medicine: Vol 1 p 361 On ordonne souvent la poudre de cloporte dans l'asthme, dans l'esquinancie(angina), l'hydropisie, dans les maladies où il faut fondre et résoudre les humeurs, purifier le sang, etc.

  • taxonomy:

First taxonomic reference: linnaeus oniscus https://www.biodiversitylibrary.org/item/10277#page/658/mode/1up

First use of oniscidea: Latreille Histoire naturelle, générale et particulière des crustacés et des insectes Vol 3 p 42 oniscides

Key taxonomic milestone: Budde-lunds first oniscidea catalog

RESEARCH ON THE BIOLOGY OF TERRESTRIAL ISOPODS: A HISTORICAL SURVEY by Helmut Schmalfuss (http://actazool.nhmus.hu/64/3/ActaZH_2018_Vol_64_3_193.pdf)

References

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  1. ^ "WoRMS - World Register of Marine Species - Oniscidea". www.marinespecies.org.
  2. ^ Schmidt, Christian (5 December 2008). "Phylogeny of the Terrestrial Isopoda (Oniscidea): a Review" (PDF). Arthropod Systematics & Phylogeny. 66 (2). Museum für Tierkunde Dresden: 191–226. eISSN 1864-8312 – via Naturmuseum Senckenberg.
  3. ^ Broly, Pierre; Deville, Pascal; Maillet, Sébastien (2012-12-23). "The origin of terrestrial isopods (Crustacea: Isopoda: Oniscidea)". Evolutionary Ecology. 27 (3): 461–476. doi:10.1007/s10682-012-9625-8. ISSN 0269-7653.
  4. ^ Helmut Schmalfuss (2003). "World catalog of terrestrial isopods (Isopoda: Oniscidea) — revised and updated version" (PDF). Stuttgarter Beiträge zur Naturkunde, Serie A. 654: 341 pp.
  5. ^ Sfendourakis, Spyros; Taiti, Stefano (2015-07-30). "Patterns of taxonomic diversity among terrestrial isopods". ZooKeys. 515: 13–25. doi:10.3897/zookeys.515.9332. ISSN 1313-2970.{{cite journal}}: CS1 maint: unflagged free DOI (link)
  6. ^ a b Helmut, Schmalfuss, (1998-01-01). "EVOLUTIONARY STRATEGIES OF THE ANTENNAE IN TERRESTRIAL ISOPODS". Journal of Crustacean Biology. 18 (1): 10–24. doi:10.1163/193724098X00025. ISSN 0278-0372.{{cite journal}}: CS1 maint: extra punctuation (link) CS1 maint: multiple names: authors list (link)
  7. ^ Schmidt, Christian; Wägele, Johann Wolfgang (2001-09). "Morphology and evolution of respiratory structures in the pleopod exopodites of terrestrial Isopoda (Crustacea, Isopoda, Oniscidea)". Acta Zoologica. 82 (4): 315–330. doi:10.1046/j.1463-6395.2001.00092.x. ISSN 0001-7272. {{cite journal}}: Check date values in: |date= (help)

General reference list

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In very, very rough order of importance. Many sources are paywalled, use Sci-hub and Libgen

References Dump

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-=-=-=-Notes-=-=-=-=-

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  • ? Article title should be changed to Oniscidea/Woodlouse should redirect to Oniscidea.?
  • Pillbug currently redirects to Armadillidiidae. Pillbugs should go to disambiguation like roly poly or doodle bug as pill millipedes are also called pillbugs
  • ?Pill millipedes and pill woodice section to merge into ...
  • Remove section https://en.wikipedia.org/wiki/Woodlouse#British_Isles --> List of woodlice of the british isles to go to See also section
  • List of woodlice of france can be created from vandel 1960
  • List of woodlice of US and Canada can be created from https://decapoda.nhm.org/pdfs/4571/4571.pdf