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

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.

Verifiability of genus-level classification under quantification and parsimony theories: a case study of follicucullid radiolarians

“…However, Wang et al (2012) noticed that it is better to place Pa. monacantha in Pseudoalbaillella because of the evolutionary transitions, as mentioned earlier, and this opinion was confirmed by Ito et al (2015). Ito et al (2016) also drew a direct evolutionary connection from Parafollicucullus to Follicucullus , but this was not supported by our analyses, in which we identify a relationship between Longtanella and Follicucullus (Fig. 4).…”

New timing and geochemical constraints on the Capitanian (Middle Permian) extinction and environmental changes in deep-water settings: evidence from the Lower Yangtze region of South China

“…Pseudoalbaillella, a long-lived genus that diversified and dominated in the Late Carboniferous to Middle Permian, became relatively smaller in body size and less abundant in the Follicucullus monacanthus zone (Isozaki, 2009b), and then experienced global extinction before the G-LB (Wang and Yang, 2011). Follicucullus, a dominant genus that appeared in the Capitanian (Isozaki, 2009b;Wang and Yang, 2011;Ito et al, 2016;Xiao et al, 2018), also became less dominant at the end of the Capitanian but survived into the Lopingian (Isozaki, 2009b). In west Texas (USA), these Middle Permian radiolarians all disappeared before the end Capitanian (e.g., Nestell and Nestell, 2010).…”