Data from: Phylogenomics resolves a spider backbone phylogeny and rejects a prevailing paradigm for orb web evolution

Spiders represent an ancient predatory lineage known for their
extraordinary biomaterials, including venoms and silks. These adaptations
make spiders key arthropod predators in most terrestrial ecosystems.
Despite ecological, biomedical, and biomaterial importance, relationships
among major spider lineages remain unresolved or poorly supported. Current
working hypotheses for a spider “backbone” phylogeny are largely based on
morphological evidence, as most molecular markers currently employed are
generally inadequate for resolving deeper-level relationships. We present
here a phylogenomic analysis of spiders including taxa representing all
major spider lineages. Our robust phylogenetic hypothesis recovers some
fundamental and uncontroversial spider clades, but rejects the prevailing
paradigm of a monophyletic Orbiculariae, the most diverse lineage,
containing orb-weaving spiders. Based on our results, the orb web either
evolved much earlier than previously hypothesized and is ancestral for a
majority of spiders or else it has multiple independent origins, as
hypothesized by precladistic authors. Cribellate deinopoid orb weavers
that use mechanically adhesive silk are more closely related to a diverse
clade of mostly webless spiders than to the araneoid orb-weaving spiders
that use adhesive droplet silks. The fundamental shift in our
understanding of spider phylogeny proposed here has broad implications for
interpreting the evolution of spiders, their remarkable biomaterials, and
a key extended phenotype—the spider web.

蜘蛛是一类古老的捕食性演化支，以其独特的生物材料（biomaterials）——包括毒液与蛛丝——闻名于世。这类适应性特征使得蜘蛛成为绝大多数陆地生态系统中的核心节肢动物捕食者。尽管蜘蛛在生态、生物医学及生物材料领域均具有重要价值，但主要蜘蛛演化支之间的系统发育关系仍未明确，或支持度不足。当前主流的蜘蛛“主干”系统发育假说大多基于形态学证据，因为目前常用的多数分子标记（molecular markers）通常难以有效解析深层演化关系。本研究针对涵盖所有主要蜘蛛演化支的类群开展了系统发育基因组学分析。我们得到的稳健系统发育假说恢复了数个基础且无争议的蜘蛛演化支，但否定了当前主流的单系圆蛛类（Orbiculariae）范式——该类群是包含结圆网蜘蛛的物种多样性最高的演化支。基于本研究结果，圆网要么比此前假说中起源的时间早得多，是多数蜘蛛的祖先性状；要么如分支分类学前的研究者所提出的那样，经历了多次独立起源。使用机械粘附蛛丝的具筛器恐蛛类圆网蜘蛛（cribellate deinopoid orb weavers），与一个主要由无结网蜘蛛组成的多样演化支亲缘关系更近，而非使用粘性液滴蛛丝的类圆蛛类（araneoid）结圆网蜘蛛。本研究提出的蜘蛛系统发育认知的根本性转变，对于阐释蜘蛛的演化历程、其卓越的生物材料，以及关键的延伸表型——蛛网（spider web）——均具有广泛的启示意义。