A standardized terminology of spines in the order Siluriformes

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Gustavo A. Ballen & Mario C. C. De Pinna. 2021. A standardized terminology of spines in the order Siluriformes (Actinopterygii: Ostariophysi). Zoological Journal of the Linnean Society, Published March 27, 2021 (Not yet assigned to a volume):25 pages.

Abstract
A standardized terminology for the anatomy of pectoral- and dorsal-fin spines in the order Siluriformes is proposed based on an extensive literature review and direct examination of representatives of the order. The adult anatomy of the spines is described in detail. Terminology of various spine parts are reviewed and standardized, each term provided with a synonymic list organizing previous usage. Most of the structures treated have been recorded and named in the literature, but some are herein named for the first time. A quantitative approach is proposed for orienting decisions on name usage, aiming at minimizing differences between the terminology proposed and the vast amount of pre-existing literature, herein called the cost function. It is expected that this system will aid efforts in organizing the chaotic anatomical nomenclature of the appendicular skeleton in Siluriformes, and provide a solid basis for advances in comparative anatomy and nomenclature. The proposed terminology system has potential application on a number of fields that utilize information from catfish spines, ranging from taxonomy to phylogenetic systematics to paleontology and archaeology.

https://academic.oup.com/zoolinnean/adv ... m=fulltext

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Final citation: Ballen, G.A. & M.C.C De Pinna. (2022). A standardized terminology of spines in the order Siluriformes (Actinopterygii: Ostariophysi), Zoological Journal of the Linnean Society, 194(2), 601–625.

https://doi.org/10.1093/zoolinnean/zlab008.
https://academic.oup.com/zoolinnean/art ... 1/6191677/

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Kubicek, K. M., Britz, R., & Conway, K. W. (2023). Comment on ‘A standardized terminology of spines in the order Siluriformes (Actinopterygii: Ostariophysi)’by Ballen and de Pinna (2021). Zoological Journal of the Linnean Society, zlad159.
https://doi.org/10.1093/zoolinnean/zlad159
https://academic.oup.com/zoolinnean/adv ... 59/7379315

Abstract
Homology is the foundation of any comparative evolutionary study, and as structures previously considered homologous are found to be convergent, and vice versa, terminology needs to be changed to reflect homology. The dorsal- and pectoral fin-spines of catfishes (order Siluriformes) are morphologically diverse and ornamentations adorning the anterior and posterior edges of the spines have regularly been used in systematic studies of the group. Building on Vanscoy et al. (2015), Kubicek et al. (2019) showed that some of the ornamentations of siluriform fin-spines previously considered homologous result from two different developmental pathways, and presented a terminology based on the homology of these structures. In their recent paper, Ballen and de Pinna (2021) proposed a new terminology for various catfish fin-spine structures, including fin-spine ornamentation. However, homology was not considered and, instead, their terminology is based on the general shape of the ornamentation to allow for ‘unambiguous use’ in various applications, including the placement of fossil fin-spines into well-defined clades of catfishes. We show that the terminology proposed by Ballen and de Pinna (2021) is problematic as it confuses non-homologous conditions into the same state and thus undermines the usefulness of fin-spine ornamentation as a character in comparative evolutionary studies of siluriforms.

Key words: anatomy, morphology, skeleton, homology, otophysi

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Ballen, G.A. & M.C. de Pinna. (2024). A reply to a comment on Ballen and de Pinna (2021) by Kubicek, Britz, and Conway. Zoological Journal of the Linnean Society, p.zlae038.
https://doi.org/10.1093/zoolinnean/zlae038
https://academic.oup.com/zoolinnean/adv ... m=fulltext

Extract
Appendicular anatomy has proven to be useful in the study of catfishes (Siluriformes), a group with nearly 4000 species of mainly freshwater fishes (with major marine representation in families Ariidae and Plotosidae, and minor in Aspredinidae, Auchenipteridae, and Pangasiidae) found currently in all continents. Studies on this order trace back to Linnaeus and Arctaedius, and comprise a massive literature in which multiple authors have noted the usefulness of characters associated with fin spines for subjects ranging from taxonomy to the study of the fossil record and toxicology (Ballen and de Pinna 2021).

Recently, Kubicek et al. (2023) published a paper offering disagreements with some specific aspects of our previous work, for which we are providing a reply herein. The main goal of our work was to ‘propose a general standard for the descriptive anatomy of catfish spines, with a general overview of the subject and a revised synoptic list of terms’ (Ballen and de Pinna 2021). We did this by reviewing the massive amount of terms already used in the literature, of which spine shaft ornament terms are but a small subset of 126 terms accounting for the morphology of both dorsal and pectoral spines (77 for the pectoral spine and 49 for the dorsal spine). Most of the terms were not proposed for the first time in our paper, but instead previously published elsewhere, with just 14 original ones, including three for the shaft ornaments. The entire critique of Kubicek, Britz, and Conway rests on those three ornament terms.