2026年8月26日，中国科学院南京地质古生物研究所蔡晨阳等科学家在《自然》发表研究，报道了距今约3.24亿年的昆虫新物种Chosha praecursor，为昆虫早期演化及陆地殖民化提供了关键化石证据。

分子钟分析、保存异常完好的两栖类干多足动物化石以及海蝎子化石，近期挑战了关于动物陆地殖民化时间线的经典假设，表明陆地生态系统可能早在寒武纪就已存在。然而，最成功的动物类群——昆虫的早期演化历史至今仍难以捉摸，因为其早期多样化时期受时间分化估算的约束，恰好落在化石记录中臭名昭著的“六足动物空白期”内。在此，研究人员描述了来自美国德克萨斯州Tesnus组石炭纪（晚密西西比世，约3.24亿年前）的Chosha praecursor新属新种。交叉偏振光成像显示，C. praecursor具有昆虫的独有衍征，包括产卵器和末端丝状物，但与冠群昆虫有所不同，最显著的区别在于其具有分节且带有桨状修饰的腹部附肢。系统发育重建将C. praecursor恢复为六足动物，并强烈支持将其置于昆虫的早期分化位置。对另外三个难以归类的六足动物化石——泥盆纪的Leverhulmia以及来自Mazon Creek化石库的两个尚未描述的石炭纪化石——的重新研究，揭示了古生代无翅昆虫多样化的身体构型。这些干群化石共同代表了最早的无争议昆虫，并在一定程度上调和了分子钟估算与化石记录之间的不一致。Chosha不寻常的鳃状腹部附肢表明，至少部分干昆虫具有半水生生活方式，这修正了人们对昆虫形态构型演化的认识。

附：英文原文

Title: Amphibious stem-insect sheds light on colonization of land

Author: Tihelka, Erik, Vsquez, Carlos, Engel, Michael S., Schram, Frederick R., Lozano-Fernandez, Jesus, Cai, Chenyang

Issue&Volume: 2026-08-26

Abstract: Molecular clock analyses1 trace fossils exceptionally preserved amphibious stem-myriapods and sea scorpions have recently challenged classical assumptions about the timeline of the animal colonization of land, suggesting that terrestrial ecosystems may date back as far as the Cambrian period. However, the early evolutionary history of the most successful clade of animals, the insects, has remained elusive, as the period of their early diversification constrained by time divergence estimates falls within the notorious ‘hexapod gap’ in the fossil record. Here we describe Chosha praecursor gen. et sp. nov. from the Carboniferous period (Late Mississippian epoch, approximately 324 million years ago) Tesnus Formation in Texas. Cross-polarized light imaging reveals that C. praecursor possesses insect apomorphies including an ovipositor and a terminal filament but differs from crown-group insects, most notably with respect to the presence of multisegmented abdominal legs with paddle-like modifications. Our phylogenetic reconstruction recovers C. praecursor as a hexapod, strongly favouring its placement as an early-diverging insect. A revision of three other enigmatic hexapod fossils, the Devonian period Leverhulmia and two undescribed Carboniferous fossils from the Mazon Creek Lagersttte, demonstrates diverse body organization in Palaeozoic wingless insects. Together, these stem-group fossils represent the earliest uncontested insects and partly reconcile the incongruence between molecular clock estimates and the fossil record. The unusual abdominal gill-like appendages of Chosha suggest a semiaquatic mode of life in at least some stem-insects and revise our understanding of the assembly of insect morphological organization.

DOI: 10.1038/s41586-026-10961-2

Source: https://www.nature.com/articles/s41586-026-10961-2