Possible Boundaries between Pseudoalbaillella and Follicucullus (Follicucullidae, Albaillellaria, Radiolaria): An Example of Morphological Information from Fossils and Its Use in Taxonomy

Tsuyoshi Ito^1,2*, Qinglai Feng¹ and Atsushi Matsuoka³

¹State Key Laboratory of Geological processes and Mineral Resources, China University of Geosciences, Wuhan 430074, China
²Institute of Geology and Geoinformation, Geological Survey of Japan, AIST, AIST Tsukuba Central 7, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8567, Japan
³Department of Geology, Faculty of Science, Niigata University, Niigata 950-2181, Japan
*E-mail address: ito-t@aist.go.jp

(Received July 25, 2015; Accepted April 14, 2016)

Abstract. Recently, a middle Permian radiolarian species was reassigned from Follicucullus monacanthus Ishiga et Imoto to Pseudoalbaillella monacantha on the basis of the diagnoses of the genera Pseudoalbaillella Ormiston et Babcock and Follicucullus Holdsworth et Jones. This revision results in redrawing of the boundary between the genera; however, different boundaries could be drawn using different perspectives. As an example of fossil morphological information and its use in taxonomy, this article discusses possible boundaries from the traditional, diagnostic, phylogenetic and evolutionary perspectives. We advocate using the diagnostic boundary (between Ps. monacantha and F. porrectus Rudenko) to avoid taxonomic confusion and inconvenience.

Keywords: Morphology, Taxonomy, Radiolaria, Generic Boundary, Permian