Datasets associated with the manuscript entitled "Pyrumthecina Infraorder Nov.: Revisiting the morphological diversity and identifying the phylogenetic home of Argynnia within Arcellinida (Tubulinea:Amoebozoa)"

Arcellinida is a diverse lineage of testate amoebae within Amoebozoa, whose evolutionary history has been clarified through phylogenomics. These efforts have led to a stable classification of the group into suborders and infraorders. However, several taxa, such as the genus <i>Argynnia</i>, remain unplaced due to ambiguous morphology and unresolved positions in single-gene phylogenies. In this study, we explore the diversity of <i>Argynnia</i> by presenting new records of species sampled across Brazil. To address its longstanding taxonomic uncertainty, we performed a phylogenomic analysis incorporating transcriptomic data from the Protist 10,000 Genomes isolate P10K-MW-000941 (P10K941). Through single-gene phylogenies, this isolate was shown to be closely related to <i>Argynnia</i>, which previously lacked genomic-level data. Here, we further confirm this relationship and present a 227-gene phylogenomic reconstruction that identifies the placement of P10K941 within Arcellinida, thereby resolving the phylogenetic placement of <i>Argynnia</i>. We obtained a curated, contaminant-free phylogenomic dataset for Arcellinida, including the P10K941, through the PhyloFisher workflow. Our analysis recovers P10K941 as a well-supported long-branch, sister to the infraorder Longithecina. Given this phylogenomic placement, along with Argynnia’s characteristic morphology and the consistent results of single-marker analyses placing it outside existing infraorders, we propose the Pyrumthecina infraorder novum and the family Argynniidae family novum to accommodate the P10K941 isolate and all <i>Argynnia</i> species. These findings resolve the phylogenetic position of <i>Argynnia</i> and allow for interpreting shell evolution and deep diversification patterns within Arcellinida. The recognition of Pyrumthecina also highlights the likely existence of deeply branching lineages among arcellinid taxa currently classified as <i>incertae</i><i> sedis</i>.

盘变形目（Arcellinida）是变形虫门（Amoebozoa）内一类多样的有壳变形虫（testate amoebae）类群，其演化历史已通过系统发育基因组学（phylogenomics）研究得到厘清。相关研究已将该类群稳定划分为亚目与下目级分类单元。然而，包括阿金虫属（Argynnia）在内的多个类群仍因形态特征模糊、单基因系统发育树拓扑结构尚未解析，暂未被纳入上述分类框架。本研究通过采集自巴西各地的新记录物种，探究了阿金虫属的物种多样性。为解决该类群长期存在的分类学不确定性，我们整合了原生生物10000基因组计划（Protist 10,000 Genomes）分离株P10K-MW-000941（简称P10K941）的转录组数据，开展了系统发育基因组学分析。此前的单基因系统发育分析显示，该分离株与阿金虫属亲缘关系紧密，但彼时阿金虫属尚无基因组级别的数据。本研究进一步验证了这一亲缘关系，并通过包含227个基因的系统发育基因组重建，明确了P10K941在盘变形目中的系统发育位置，由此解决了阿金虫属的分类定位难题。我们通过PhyloFisher分析流程，构建了经过质控、无污染物的盘变形目系统发育基因组数据集，其中包含P10K941分离株。分析结果显示，P10K941为一支支持度较高的长支类群，与长壳下目（Longithecina）互为姐妹群。结合这一系统发育基因组定位结果、阿金虫属的典型形态特征，以及单标记分析一致显示其位于现有下目之外的结果，我们提议建立Pyrumthecina新下目与阿金虫科（Argynniidae）新科，以容纳P10K941分离株及所有阿金虫属物种。本研究明确了阿金虫属的系统发育位置，为解析盘变形目的壳体演化与深层多样化模式提供了依据。新界定的Pyrumthecina新下目也提示，当前被归类为地位未定（incertae sedis）的盘变形虫类群中，可能存在大量深层分支的演化支系。