Racheliella, a new mathildoid gastropod genus (Gastropoda, lower Heterobranchia) from the Late Triassic St. Cassian Formation (N Italy)
Racheliella, a new mathildoid gastropod genus (Gastropoda, lower Heterobranchia) from the Late Triassic St. Cassian Formation (N Italy)
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Racheliella，来自晚三叠世圣卡西安组（意大利北部）的一个新的腹足类腹足动物属（腹足纲，下异鳃纲）
DOI：
10.1127/njgpa/2018/0713
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发表时间：
2018
影响因子：
0.8
通讯作者：
Nützel
中科院分区：
文献类型：
--
作者：
Nützel
在晚三叠世（卡尼期）圣卡西安组（北意大利）的腹足类Loxonema mersai中发现了一个保存完好的原海螺，表明该物种的幼虫壳具有同轴异旋性。本种不代表古生代的Loxonema属（具有志留纪的模式种），而是一个新属-Racheliella-属于低异枝总科Mathildoidea。这个新属的存在增加了高多样性和差异较低的heterobranchs，包括Mathildoidea在圣卡西安组，并表明，这组是更多样化的晚三叠世比在最近的海洋。为梅尔赛刺线虫指定了一个选择型。
The discovery of a preserved protoconch in the Late Triassic (Carnian) gastropod species Loxonema mersai from the Late Triassic St. Cassian Formation (N Italy) shows that this species has a larval shell displaying coaxial heterostrophy. This species does not represent the Palaeozoic genus Loxonema (with Silurian type species) but a new genus-Racheliella-belonging to the lower heterobranch superfamily Mathildoidea. The presence of this new genus adds to the high diversity and disparity of lower heterobranchs including Mathildoidea in the St. Cassian Formation and suggests that this group was much more diversified in the Late Triassic than in Recent seas. A lectotype is designated for Loxonema mersai.