SPB Academic Publishing bv, The Hague Morphological data, extant Myriapoda, and the myriapod stem-group

The status ofMyriapoda (whether mono-, para- or polyphyletic) and position of myriapods in the Arthropoda are controversial, an impediment to evaluating fossils that may be members of the myriapod stem-group. Parsimony analysis of319 characters for extant arthropods provides a basis for defending myriapod monophyly and identifying those morphological characters that are necessary to assign a fossil taxon to the Myriapoda. The allianceofhexapods and crustaceans need not relegate myriapods to the arthropod stem-group; the Mandibulatahypothesis accom-modates Myriapoda and Tetraconata as sister taxa. No known pre-Silurianfossils have characters that convincingly place them in the Myriapoda or the myriapod stem-group. Because the strongest apomorphies ofMyriapoda are details ofthe mandible and tentorial endoskeleton,exceptional fossil preservation seem