Centre de Recherche en Paléontologie -Paris (CR2P), MNHN, CNRS, Sorbonne Université, Paris, France.
Biogéosciences, CNRS, Université Bourgogne, Dijon, France.
PeerJ. 2024 Feb 26;12:e16894. doi: 10.7717/peerj.16894. eCollection 2024.
The fossil record of gladius-bearing coleoids is scarce and based only on a few localities with geological horizons particularly favourable to their preservation (the so-called Konservat-Lagerstätten), which naturally leads to strongly limited data on geographical distributions. This emphasizes the importance of every new locality providing gladius-bearing coleoids. Here, we assess for the first time the gladius-bearing coleoid taxonomic diversity within the lower Toarcian "Schistes Cartons" of the Causses Basin (southeastern France). The material includes two fragmentary gladii, identified as and ?a sp. indet. Just with these two specimens, two (Prototeuthina and Loligosepiina) of the three (Prototeuthina, Loligosepiina and Teudopseina) suborders of Mesozoic gladius-bearing coleoids are represented. Thus, our results hint at a rich early Toarcian gladius-bearing coleoid diversity in the Causses Basin and point out the need for further field investigations in the lower Toarcian "Schistes Cartons" in this area. This new record of is only the second one in Europe and the third in the world (western Canada, Germany and now France). Based on these occurrences, we tentatively suggest that . originated in the Mediterranean domain and moved to the Arctic realm through the Viking Corridor to eventually move even farther to North America.
带剑鞘的箭石类化石记录稀缺，仅基于少数几个特别有利于其保存的地质层位（即所谓的保存完好的化石产地），这自然导致地理分布的数据非常有限。这强调了每个提供带剑鞘的箭石类新地点的重要性。在这里，我们首次评估了法国东南部考塞斯盆地下托阿尔阶“Cartons 页岩”中带剑鞘的箭石类的分类多样性。该材料包括两个不完整的剑鞘，鉴定为 和?a sp. indet. 仅这两个标本就代表了中生代带剑鞘的箭石类的三个亚目中的两个（Prototeuthina 和 Loligosepiina）。因此，我们的结果暗示考塞斯盆地早托阿尔阶带剑鞘的箭石类具有丰富的多样性，并指出需要在该地区进一步调查下托阿尔阶“Cartons 页岩”中的化石。这种新的 记录仅在欧洲是第二次，在世界范围内是第三次（加拿大西部、德国和现在的法国）。基于这些发现，我们推测 起源于地中海领域，并通过维京走廊进入北极领域，最终甚至进一步迁移到北美洲。
