Data from: Parallel evolution of jugal structures in Devonian athyridide brachiopods

Here, we describe Sinathyris crassa gen. et sp. nov., a new early Emsian (Early Devonian) athyridide brachiopod with a double spiralium from the Guangxi Province of southern China. Unlike the majority of genera of the subfamily Helenathyridinae, which possess accessory spiral lamellae developed directly from the jugal branches, the form described here shows these lamellae arising from a distally bifurcating jugal stem. These differences suggest that the double spiralium in S. crassa might have appeared independently from the double spiralium of the helenathyridins. To test the subfamily assignment of Sinathyris gen. nov., we carried out phylogenetic analyses, which indicate that the new genus is more appropriately referred to the Didymothyridinae. The cladistic analyses of the athyridides indicate that double spiralia have developed independently among these brachiopods at least five times during their evolutionary history.

本文记述产自中国南方广西壮族自治区早埃姆斯期（早泥盆世）的阿特兰贝目（athyridide）腕足动物新属新种——厚中华贝（Sinathyris crassa gen. et sp. nov.），该类群具有双腕螺结构。
与多数海伦贝亚科（Helenathyridinae）类群直接从腕锁支发出副螺旋板的特征不同，本次记述的新类群的副螺旋板源自远端分叉的腕锁茎。
上述差异表明，厚中华贝的双腕螺结构可能独立起源于海伦贝亚科类群的双腕螺结构。
为验证新属（Sinathyris gen. nov.）的亚科归属问题，本文开展了系统发育分析，结果显示该新属更适宜归入双褶贝亚科（Didymothyridinae）。
针对阿特兰贝目的分支系统学分析表明，该类腕足动物的双腕螺结构在其演化历史中至少独立起源过五次。