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Making sense of ‘lower’ and ‘upper’stem-group Euarthropoda, with comments on the strict use of the name Arthropoda von Siebold, 1848

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The ever-increasing number of studies that address the origin and evolution of Euarthropoda – whose extant
representatives include chelicerates, myriapods, crustaceans and hexapods – are gradually reaching a consensus with
regard to the overall phylogenetic relationships of some of the earliest representatives of this phylum. The stem-lineage of Euarthropoda includes numerous forms that reflect the major morphological transition from a lobopodian-type to a completely arthrodized body organization. Several methods of classification that aim to reflect such a complex evolutionary history have been proposed as a consequence of this taxonomic diversity. Unfortunately, this has also led to a saturation of nomenclatural schemes, often in conflict with each other, some of which are incompatible with cladistic-based methodologies. Here, I review the convoluted terminology associated with the classification of stem-group Euarthropoda, and propose a synapomorphy-based distinction that allows ‘lower stem-Euarthropoda’ (e.g.lobopodians, radiodontans) to be separated from ‘upper stem-Euarthropoda’ (e.g. fuxianhuiids, Cambrian bivalved forms) in terms of the structural organization of the head region and other aspects of overall body architecture. The step-wise acquisition of morphological features associated with the origins of the crown-group indicate that the node
defining upper stem-Euarthropoda is phylogenetically stable, and supported by numerous synapomorphic characters;
these include the presence of a deutocerebral first appendage pair, multisegmented head region with one or more
pairs of post-ocular differentiated limbs, complete body arthrodization, posterior-facing mouth associated with the
hypostome/labrum complex, and post-oral biramous arthropodized appendages. The name ‘Deuteropoda’ nov. is
proposed for the scion (monophyletic group including the crown-group and an extension of the stem-group) that
comprises upper stem-Euarthropoda and Euarthropoda. A brief account of common terminological inaccuracies in
recent palaeontological studies evinces the utility of Deuteropoda nov. as a reference point for discussing aspects of early euarthropod phylogeny.

Key words: Euarthropoda, Panarthropoda, Tardigrada, Onychophora, Deuteropoda nov., phylogeny, crown-group,
lobopodian, arthrodization, Aiolopoda.

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Ketersediaan

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Informasi Detail

Judul Seri

Biol. Rev.

No. Panggil

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Penerbit

: Cambridge Philosophical Society., 2016

Deskripsi Fisik

Biol. Rev. (2016), 91, pp. 255–273.

Bahasa

English

ISBN/ISSN

doi: 10.1111/brv.121

Klasifikasi

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Tipe Isi

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Tipe Media

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Tipe Pembawa

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Edisi

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Subjek

BIOLOGI

Info Detail Spesifik

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Pernyataan Tanggungjawab

Wati/Agus

Versi lain/terkait

Lampiran Berkas

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