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Phylum Arthropods: Myriapods

IF

Izyan Fatin

Transcript

WAN NURIZYAN FATIN BINTI AZMI

D2018183292

SBB3023

Biodiversity and Evolution of Protista and Animalia

PHYLUM ARTHROPODS

sub-phylum

Myriapoda

Overview

Myriapoda is a sub phylum of terrestrial arthropods, characterized by an elongated body with many segments, typically many legs, a single pair of antennae, and simple eyes. The name myriapoda suggests these invertebrates have myriad (10,000) legs, but they range from less than ten legs to up to 750 legs.

Prominent members include the centipedes, comprising the class Chilopoda, and millipedes, comprising the class Diplopoda. Two other extant classes are Pauropoda and Symphyla.

Evolution and Phylogeny

The fossil record of myriapods reaches back into the late Silurian, although molecular evidence suggests a diversification in the Cambrian Period (Friedrich and Tautz 2002), and Cambrian fossils exist which resemble myriapods (Waggoner 1996). Centipedes fossils have been found from the Devonian (Waggoner 1996).

  • Under the Mandibulata hypothesis, Myriapoda is the sister taxon to Pancrustacea, a group comprising the Crustacea and Hexapoda.
  • Under the Atelocerata hypothesis, Hexapoda is the closest, whereas under the Paradoxopoda hypothesis, Chelicerata is the closest.

This last hypothesis, although supported by few, if any, morphological characters, is supported by a number of molecular studies (Hassanin 2006)

The main characteristic

Characteristics

They have many pair of legs

The leg

They have two body section

Body Section

Trunk

  • Most or all segments have paired uniramous appendages

Head

  • One pair of antennae
  • One pair of mandibles (lower jaws) for feeding
  • One or two pairs of maxillae (upper jaws)

Respiratory exchange occurring through a tracheal system

Respiratory System

The tracheal system consists of many small internal tubes called tracheae that branch throughout the insect body. The tracheae open to the outside through holes called spiracles

Reproduce sexually

Reproduction

The sperm from the male is deposited inside the body of the female to fertilize her eggs. Depending on the species, mating can take up to two days. Myriapods do not undergo metamorphosis.

Classification

Classification

There are four classes of extant Myriapods, Chilopoda (centipedes), Diplopoda (Millipedes), Pauropoda and Symphyla

  • While each of these groups of myriapods is believed to be monophyletic, relationships among them are less certain (Regiera et al. 2005).

There also is an extinct class of myriapods, Arthropleuridea.

Facts about Centipedes

Class Chilopoda

(Centipedes)

1

They have long, flattened bodies with many segments, and with one pair of jointed appendages on each segment except the last two

2

Have venomous claws with poison glands

  • Kill their prey with poison claws – (modified legs on first segment)

3

Centipedes mothers protects its eggs until the babies grow.

  • If she feels threatened - she can abandon her eggs or even can eat them

4

The different between male and female centipedes

5

Centipedes are quick predators,

  • can eat any small animals they can catch.

Facts about millipedes

Class Diplopoda

(Millipedes)

1

  • Millipedes usually have round bodies, and have two pairs of legs on each body segment.
  • They move slowly and often tunnel into soil and dead leaves.
  • Nearly all millipede species are decomposers : they eat dead leaves, fungi, and detritus

2

Millipedes do not fight but they defend themselves -

because the exoskeleton can protect them

If another animal threatens them, they may curl up, and some give off smelly toxic chemicals(poison) to protect themselves.

  • people who are allergic to millipedes can have serious reactions: that can cause your skin to burn (it can even release hydrogen cyanide gas )

3

Millipedes make a little nest to lay their eggs

  • millipedes can live up to around 7 years old depends on their species.

4

The difference between a male and female millipede.

  • we can assume a millipedes gender by the 7th segments

Pauruspus huyxleyi, a pauropodan

Class Pauropoda

Pauropoda is another small group of small myriapods. They are typically 0.5 to 2.0 millimeters (0.2-0.8 inches) long and live in the soil on all continents except Antarctica (ALR 2009; Chapman 2005).(3) Over 700 species have been described (Chapman 2005).

Scutigerella immaculata, a symphylan

Class Symphyla

About 200 species of symphylans are known worldwide (Chapman 2005). They resemble centipedes but are smaller and translucent. Many spend their lives as soil infauna, but some live arboreally. Juveniles have six pairs of legs, but, over a lifetime of several years, add an additional pair at each molt so that the adult instar has 12 pairs of legs (OSU).

Characteristic that contributes to the success of Arthropods in term of their survival

Extra

References

References

Shear W.A. (1998) The fossil record and evolution of the Myriapoda. In: Fortey R.A., Thomas R.H. (eds) Arthropod Relationships. The Systematics Association Special Volume Series, vol 55. Springer, Dordrecht. https:/doi.org/10.1007/978-94-011-4904-4_16

Chitty, J. R. (2006). Myriapods (centipedes and millipedes). Invertebrate medicine, 195-203

https://www.newworldencyclopedia.org/entry/Myriapoda

https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/myriapoda