DOI: 10.3897/asp.83.e146637

Authors: Danilo César Ament, Eduardo A.B. Almeida

Abstract: Abstract We address an old but still controversial question of morphological phylogenetics: whether additive (or ordered) coding is beneficial to properly extracting phylogenetic information from phenotypical variation. To empirically evaluate the value of the additive coding, we compared the impact of multistate additive, non-additive, and binary codings for 14 quantitative characters in a phylogenetic analysis of a genus of phorid flies (Diptera). First, we compared which of these morphological codings were most effective for the morphological matrix to approximate the results of a molecular data set. We then compared which morphological coding strategies yielded the best Bayesian posterior probabilities when concatenated to molecular data. We also calculated consistency and retention indices for each binary element of the additive characters and contrasted these results to a measure of phylogenetic signal. Overall, these indices were lower for additive characters than for the others but still indicate reasonable accommodation in the tree. Additive coding outperformed the multistate non-additive coding by recovering higher Bayesian posterior probabilities in the concatenated dataset. Additive coding was also among the best coding strategies for the morphological matrix to approximate the phylogenetic signal from an independent source of evidence—i.e., molecular results. Therefore, quantitative information coded as additive had reasonable phylogenetic congruence with other data and improved the phylogenetic results of morphological data in most cases. These results support the use of additive coding for phylogenetic analysis and encourage other similar empirical evaluations aiming to explore the generality of the benefits of this coding method.

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DOI: 10.3897/asp.80.e86582

Authors: Mario Schädel, Margarita Yavorskaya, Rolf Beutel

Abstract: The earliest known fossil beetle †Coleopsis archaica is re-examined using Reflectance Transformation Imaging (RTI). The morphological observations are evaluated with respect to phylogenetic implications and the early evolution of Coleoptera. †Coleopsis archaica belongs to an early Permian branch of beetles, outside a monophyletic unit comprising Coleoptera (in the widest sense) excluding †Tshekardocoleidae. This clade is mainly characterized by a complex of apomorphic features: elytra with epipleura and with a close fit with the posterior body, thus forming a tightly sealed subelytral space. In contrast to this, the elytra of †C. archaica and †Tshekardocoleidae cover the metathorax and abdomen in a loose tent-like manner and posteriorly distinctly surpass the abdominal apex. So far, no synapomorphies of the two taxa from the first half of the Permian have been identified. The very short and transverse pronotum is likely an autapomorphy of †C. archaica. A thorough documentation of the structural features of early beetle fossils should have high priority. RTI is a very promising tool to obtain new and well-founded morphological data, which will allow a thorough phylogenetic evaluation of Permian beetles in future studies. We extended the conventional RTI workflow by focus merging and panoramic stitching, in order to overcome previous limitations. Taxonomic re-arrangements of stem group beetles including †C. archaica were suggested in recent studies by A.G. Kirejtshuk and co-workers. As they are not based on shared derived features they are irrelevant in a phylogenetic and evolutionary context.

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