measured more than in diameter. Fossils frequently show boreholes of insect larvae, possibly beetles similar to members of the modern family Ptinidae. Taxonomy Araucarioxylon arizonicum has alternatively been called Agathoxylon arizonicum due to Araucarioxylon being a junior synonym of Agathoxylon. They were first described in 1889 by the American paleobotanist Frank Hall Knowlton. The validity of the name Araucarioxylon arizonicum has been questioned. A. arizonicum may actually be composed of several different genera and species. A 2007 study on the syntypes used by Knowlton in describing the species has revealed that they belonged to three species. They were tentatively reclassified as Pullisilvaxylon arizonicum, Pullisilvaxylon daughertii, and Chinleoxylon knowltonii. The genus Araucarioxylon may thus be superfluous and illegitimate; and the petrified logs of Petrified Forest National Park may be composed of a greater diversity than initially believed. See also Paleobotany Araucaria Araucaria mirabilis Araucarites sanctaecrucis Nothofagus Paleobiota of the Chinle Formation References Triassic plants Flora of Arizona Flora of New Mexico Fossils of the United States Natural history of Arizona Triassic Arizona Triassic life of North America Araucariaceae Mesozoic trees Prehistoric plants of North America