Data from: A three-dimensionally preserved lobopodian from the Herefordshire (Silurian) Lagerstätte, UK

The Herefordshire (Silurian) Lagerstätte (c. 430 MYr BP) has yielded,
amongst many exceptionally preserved invertebrates, a wide range of new
genera belonging to crown-group Panarthropoda. Here we increase this
panarthropod diversity with the lobopodian Thanahita distos, a new
total-group panarthropod genus and species. This new lobopodian preserves
at least nine paired, long, slender appendages, the anterior two in the
head region and the posterior seven representing trunk lobopods. The body
ends in a short post-appendicular extension. Some of the trunk lobopods
bear two claws, others a single claw. The body is covered by paired,
tuft-like papillae. T. distos joins only seven other known
three-dimensionally preserved lobopodian or onychophoran (velvet worm)
fossil specimens and is the first lobopodian to be formally described from
the Silurian. Phylogenetic analysis recovered it, together with all
described Hallucigenia species, in a sister-clade to crown-group
panarthropods. Its placement in a redefined Hallucigeniidae, an iconic
Cambrian clade, indicates the survival of this clade to Silurian times.

赫里福德郡（志留纪）特异埋藏化石库（Lagerstätte，约4.3亿年前）产出了大量保存极为完好的无脊椎动物化石，其中涵盖了众多隶属于冠群泛节肢动物（Panarthropoda）的新属类群。本研究报道了一种新的总群泛节肢动物属种——叶足动物（lobopodian）*Thanahita distos*，进一步扩充了该类群的多样性。该新发现的叶足动物至少保留有9对修长纤细的附肢：头部区域的前两对附肢，以及躯干后方的7对躯干叶足。其躯体末端带有一处短小的附肢后延伸结构。部分躯干叶足具2枚爪，其余则仅具1枚爪。躯体表面覆盖有成对的簇状乳突。目前已知的三维保存的叶足动物或有爪动物（Onychophora，天鹅绒蠕虫）化石标本仅7份，*T. distos*为新增的第8份，同时它也是首个在志留纪地层中被正式描述的叶足动物化石。系统发育分析结果显示，该物种与所有已正式发表的怪诞虫（*Hallucigenia*）类群共同构成冠群泛节肢动物的姊妹支系。将其归入重新定义的怪诞虫科（Hallucigeniidae，一个典型的寒武纪支系），表明该支系的存续时间可延续至志留纪。