Muséum national d'Histoire naturelle, UMR7205 ISYEB MNHN-CNRS-UPMC-EPHE, Département Systématique et Évolution, CP 51, 57 rue Cuvier, 75231 Paris Cedex 05, France.
Zootaxa. 2021 Apr 19;4963(2):zootaxa.4963.2.1. doi: 10.11646/zootaxa.4963.2.1.
Detailed studies of the middle Ilerdian (lower Ypresian) blue marls of the Gulf of Languedoc (Corbières, Aude, France), belonging to the north Pyrenean foreland basin, have revealed a more abundant and diverse crinoid fauna than previously documented from the Lower Eocene. Here we describe five species of stalked crinoids in the family Rhizocrinidae (Cherbonniericrinus requiensis n. sp., ?Democrinus elongatus, Globulocrinus amphoraformis n. gen., n. sp., Pseudoconocrinus doncieuxi and P. lavadensis n. sp.), one barnacle-like species in the stalkless family Holopodidae (Holopus plaziati n. sp.) and a single feather star in the family Conometridae (Amphorometra atacica). Several sites have yielded brachials and rhizoids in addition to abundant aboral cups and columnals indicating in situ fossilisation of the dissociated skeletal elements. P. lavadensis n. sp. and ?D. elongatus have been collected only from outcrops located in the upper part of the middle blue marls, while P. doncieuxi predominates, with a wide range of morphological variation, in the lower blue marls. The fossil assemblage at the locality of Réqui near Montlaur differs from the others in the smaller size of most individuals and the presence of H. plaziati n. sp., C. requiensis n. sp., G. amphoraformis n. gen., n. sp., and P. doncieuxi suboblongus n. subsp. This particular association with high juvenile mortality corresponds to an unstable environment with mixed substrates (muddy and rocky). The crinoid fauna of the Corbières appears to be the most diverse of Early Eocene age known to date. With the fauna of the London Clay, a boreal formation of the same age, it shares the presence of the genera Democrinus and Amphorometra in an open-sea environment. A comparison with extant faunas allows the depth of deposition at the Ypresian sites in the Gulf of Languedoc to be estimated between from 100 and 140 meters.
对属于北比利牛斯山前盆地的朗格多克湾（奥德省科比埃地区）中伊勒迪恩中期（下伊利里亚期）蓝泥灰岩的详细研究显示，这里的有孔虫动物群比以前记录的下始新统更为丰富多样。本文描述了 5 种腕足动物，隶属于 Rhizocrinidae 科（Cherbonniericrinus requiensis n. sp.、Democrinus elongatus、Globulocrinus amphoraformis n. gen., n. sp.、Pseudoconocrinus doncieuxi 和 P. lavadensis n. sp.），1 种无腕足动物的 Holopodidae 科（Holopus plaziati n. sp.）和 1 种羽星科（Conometridae）（Amphorometra atacica）。除了大量的背壳杯和柱状体外，几个地点还发现了腕骨和根骨，表明这些分离的骨骼元素是原地化石。P. lavadensis n. sp.和？D. elongatus 仅从位于中蓝泥灰岩上部的露头中采集到，而 P. doncieuxi 则在下部蓝泥灰岩中占主导地位，具有广泛的形态变异。位于蒙劳尔附近的雷基地点的化石组合与其他地点的不同之处在于大多数个体的体型较小，并且存在 H. plaziati n. sp.、C. requiensis n. sp.、G. amphoraformis n. gen., n. sp.和 P. doncieuxi suboblongus n. subsp. 这种与高幼体死亡率相关的特殊组合对应于一个不稳定的环境，具有混合基质（泥质和石质）。科比埃地区的有孔虫动物群似乎是迄今为止已知的始新世最具多样性的动物群。与同一时代的北海陆相伦敦黏土动物群相比，它们共同拥有生活在开阔海域的 Democrinus 和 Amphorometra 属。与现生动物群的比较可以估计朗格多克湾伊勒迪恩期遗址的沉积深度在 100 到 140 米之间。
