A new morphological phylogeny of Malacostraca comparing the application of character dependencies and implied weighting.

Abstract

Using a new character matrix composed of revised matrices of previous analyses and new morphological findings, the phylogeny of Malacostraca (Pancrustacea) is analysed anew with 207 characters for 35 terminal taxa across all recognized orders. Particular emphasis was placed on methodological versatility, including different degrees of implied weighting and one of the first applications of methods recently developed in TNT (with the xl inks-command) for considering character dependencies. With >67% of ontological dependencies our character matrix offers a perfect opportunity for putting this new methodology to the test. In particular, we can demonstrate the significant impact of character dependencies and conclusively argue the usefulness of "xlinks" (or the consideration of character dependencies in general). Furthermore, the multimethod framework also enables a comparative evaluation of established and new approaches, and the resulting cladograms thereof. Although our various results leave many questions about the phylogeny of Malacostraca unanswered, clear support is emerging for some monophyla, whereas some surprising findings give reason for methodological reflection. Also, the necessity for an increased attention in terms of taxon sampling and additional character examinations in certain groups becomes obvious. We herein provide (i) an R-function for automatically translating the character dependency syntax proposed by Grams and Richter (Cladistics, 2023, 39, 437) into xlinks-commands for TNT; and (ii) a TNT-script for analysing a character matrix successively under various k-values for implied weighting.