User:Animalparty/milliipede classification

The living members of the Diplopoda are divided into sixteen orders in two subclasses. The basal subclass Penicillata contains small species whose exoskeleton is not calcified, and which are covered in setae or bristles. All other millipedes belong to the subclass Chilognatha, consisting of two infraclasses: the infraclass Pentazonia containing the short-bodied pill millipedes, and the infraclass Helminthomorpha (worm-like millipedes) containing the great majority of the species.

The classification of millipedes from 1758 as new discoveries and methods of analysis.

History

The formal science of millipede biology and taxonomy is called diplopodology, the study of diplopods. The history of scientific millipede classification started with Carl Linnaeus, who in his 10th edition of Systema Naturae, 1758, named seven species of Julus as "Insecta Aptera" (wingless insects). In 1802, the French zoologist Pierre André Latreille proposed the name Chilognatha as the first group of what are now the Diplopoda, and in 1840 the German naturalist Johann Friedrich von Brandt produced the first detailed classification. The name Diplopoda itself was coined in 1844 by Henri Marie Ducrotay de Blainville. In the following decades, millipede taxonomy was driven by relatively few researchers at any given time, with major contributions by Carl Attems, Karl Verhoeff and Ralph V. Chamberlin, who each described over 1,000 species, as well as Orator F. Cook, Filippo Silvestri, R. I. Pocock, and Henry W. Brölemann. The 50-year period from 1890 to 1940, when the seven researchers above were working, was a period when the science of diplopodology flourished: rates of species descriptions during this period was on average the highest in history, sometimes exceeding 300 per year.

In 1971, Dutch biologist C. A. W. Jeekel published a comprehensive listing of all known millipede genera and families described between 1758 and 1957 in his Nomenclator Generum et Familiarum Diplopodorum, a work credited as launching the "modern era" of millipede taxonomy. In 1980, American biologist Richard L. Hoffman published a classification of millipedes which recognized the the Penicillata, Pentazonia, and Helminthomorpha,, and the first phylogenetic analysis of millipede orders using modern cladistic methods was published in 1984 by Henrik Enghoff of Denmark. A 2003 classification by American myriapodologist Rowland Shelley is similar to classification originally proposed by Verhoeff, and remains the currently accepted classification scheme (shown below), despite more recent molecular studies which propose a number of conflicting relationships. A 2011 summary of millipede family diversity by William A. Shear placed the order Siphoniulida within the larger group Nematomorpha.

Diplopoda	Penicillata Polyxenida Chilognatha Pentazonia Limacomorpha Glomeridesmida Oniscomorpha Glomerida Sphaerotheriida Helminthomorpha Colobognatha Platydesmida Siphonocryptida Polyzoniida Siphonophorida Eugnatha Nematophora Chordeumatida Callipodida Stemmiulida Merochaeta Polydesmida Juliformia Julida Spirobolida Spirostreptida Siphoniulida

Classification

The living members of the class (biology) Diplopoda are divided into sixteen biology|orders in two subclasses. There are also nine extinct orders. The basal subclass Penicillata contains a single order of small species whose exoskeleton is not calcified, and which are covered in setae or bristles. All other millipedes belong to the subclass Chilognatha.

The subclass Chilognatha is divided into two infraclasses.

Polyxenus lagurus, a species of the order Polyxenida

Glomeris marginata, a pill millipede of the order Glomerida

Octoglena sierra, a species of the order Polyzoniida

Anadenobolus monilicornis, a species of the order Spirobolida

Harpaphe haydeniana, a species of the order Polydesmida

The infraclass Pentazonia contains the short-bodied pill millipedes, which are capable of rolling themselves into a ball ("volvation"). The infraclass Helminthomorpha (worm-like contains the great majority of millipede species.

The higher-level classification of millipedes is presented below, based on Shear, 2011, and Shear & Edgecombe, 2010 (extinct groups). Recent cladistic and molecular studies have challenged traditional classification schemes (see Phylogeny, below), and in particular the position of the orders Siphoniulida and Polyzoniida is not yet well established. The placement and positions of extinct groups (†) known only from fossils is tentative and not fully resolved.

Class Diplopoda de Blainville in Gervais, 1844

• Subclass Penicillata Latrielle, 1831
  • Order Polyxenida Verhoeff, 1934
• Subclass †Arthropleuridea (placed in Penicillata by some authors)
  • Order †Arthropleurida
  • Order †Eoarthropleurida
  • Order †Microdecemplicida
• Subclass Chilognatha Latrielle, 1802
  • Order †Zosterogrammida Wilson, 2005 (Chilognatha incertae sedis)
  • Infraclass Pentazonia Brandt, 1833
    • Order †Amynilyspedida Hoffman, 1969
    • Superorder Limacomorpha Pocock, 1894
      
      • Order Glomeridesmida Cook, 1895
    • Superorder Oniscomorpha Pocock, 1887
      • Order Glomerida Brandt, 1833
      • Order Sphaerotheriida Brandt, 1833
  • Infraclass Helminthomorpha Pocock, 1887
    • Order †Pleurojulida Schneider & Werneburg, 1998 (possibly sister to Colobognatha)
    • Superorder †Archipolypoda Scudder, 1882
      • Order †Archidesmida
      • Order †Cowiedesmida
      • Order †Euphoberiida
      • Order †Palaeosomatida
    • Subterclass Colobognatha Brandt, 1834
      • Order Platydesmida Cook, 1895
      • Order Polyzoniida Cook, 1895
      • Order Siphonocryptida Cook, 1895
      • Order Siphonophorida Newport, 1844
    • Subterclass Eugnatha Attems, 1898
      • Superorder Juliformia Attems, 1926
        • Order Julida Brandt, 1833
        • Order Spirobolida Cook, 1895
        • Order Spirostreptida Brandt, 1833
        • Superfamily †Xyloiuloidea Cook, 1895 (Sometimes aligned with Spirobolida)
      • Superorder Nematophora Verhoeff, 1913
        • Order Callipodida Pocock, 1894
        • Order Chordeumatida Pocock 1894
        • Order Stemmiulida Cook, 1895
        • Order Siphoniulida Cook, 1895
      • Superorder Merochaeta Cook, 1895
        • Order Polydesmida Pocock, 1887

Hoffman 1980

	Penicillata Polyxenida Pentazonia Oniscomorpha Glomerida Sphaerotheriida Limacomorpha Glomeridesmida Helminthomorpha Typhlogena Platydesmida Siphonophorida Ommatophora Polyzoniida Siphoniulida Monocheta Stemmiulida Coelocheta Chordeumatida Callipodida Merocheta Polydesmida Anocheta Spirobolida Diplocheta Spirostreptida Julida

Shelley 2003

	Penicillata Polyxenida Pentazonia Glomeridesmida Glomerida Sphaerotheriida Helminthomorpha Colobognatha Platydesmida Siphonocryptida Polyzoniida Siphonophorida Eugnatha Nematophora Chordeumatida Callipodida Stemmiulida Merochaeta Polydesmida Juliformia Julida Spirobolida Spirostreptida Siphoniulida

2003 Phylogeny inferred through morphology

While most millipede orders are considered monophyletic, the relationship of the orders to each other (the so-called higher level phylogeny), has still not been unambiguously resolved, and different phylogenetic hypotheses have been proposed. Common findings include a basal Penicillata, and a monophyletic Helminthomporpha and Pentazonia. The composition of other groups is equivocal.

The cladogram below shows a phylogeny inferred from morphological traits in 2003, supplemented with extinct groups (†) from two recent reviews The tentative placement of extinct groups (†) is indicated by dotted lines. The orders Siphoniulida, Siphonocryptida, †Pleurojulida, and †Zosterogrammida are not shown.

Californiulus chamberlini, a species of the order Julida

	Peniciillata Polyxenida Chilognatha †Arthropleuridea Pentazonia Oniscomorpha Glomerida Sphaerotheriida Glomeridesmida †Amynilyspedida Helminthomorpha Colobognatha Platydesmida Polyzoniida Siphonophorida Eugnatha Nematophora Chordeumatida Callipodida Stemmiulida Merochaeta Polydesmida Juliformia Julida Spirobolida Spirostreptida †Xyloiuloidea †Archipolypoda

2007 DNA and morphology

The cladogram below shows millipede phylogeny inferred from a total-evidence analysis of morphological traits and molecular data published in 2007. The relative placement of several orders differs from previous studies, but the authors caution that it is premature to propose classification changes based on this study alone.

Penicillata	Polyxenida
Chilognatha	Pentazonia Glomerida Glomeridesmida Sphaerotheriida Helminthomorpha Siphoniulida Stemmiulida Polydesmida Polyzoniida Siphonophorida Siphonocryptida Platydesmida Chordeumatida Callipoda Juliformia Spirobolida Spirostreptida Julida

Fossil record

In addition to the 16 living orders, there are 9 extinct orders and one superfamily known only from fossils. The relationship of these to living groups and to each other is controversial. The extinct Arthropleuridea was long considered a distinct myriapod class, although work in the early 21st century established the group as a subclass of millipedes. Several living orders also appear in the fossil record. Below are two proposed arrangements of fossil millipede groups. Extinct groups are indicated with a dagger (†). The extinct order Zosterogrammida, a chilognath of uncertain position, is not shown.

Penicillata †Arthropleuridea †Arthropleurida †Eoarthropleurida Polyxenida †Microdecemplicida Chilognatha

Alternate hypothesis of fossil relationships

Diplopoda	Penicillata Polyxenida Chilognatha †Arthropleuridea †Arthropleurida †Eoarthropleurida †Microdecemplicida †Amynilyspedida Helminthomorpha †Archipolypoda †Archidesmida †Cowiedesmida †Euphoberiida †Palaeosomatida †Pleurojulida Colobognatha Eugnatha Nematophora Polydesmida Juliformia Julida Spirobolida Spirostreptida †Xyloiuloidea