The Langenberg Quarry near Bad Harzburg has yielded the first Jurassic stem therian mammal of Germany, recovered from Kimmeridgian (Late Jurassic) near shore deposits of a palaeo-island within the Lower Saxony Basin of the European archipelago. The new stem therian is represented by one lower and three upper molars. Hercynodon germanicus gen. et sp. nov. is attributed to the Dryolestidae, a group of pretribosphenic crown mammals that was common in western Laurasia from the Middle Jurassic to the Early Cretaceous. The new taxon is characterised by small size, a reduced cusp pattern in the upper molars lacking a metacone, and enhancement of the shearing crests paracrista and metacrista. Phylogenetic analysis identified Hercynodon gen. nov. as sister taxon of Crusafontia from the Lower Cretaceous (Barremian) of Spain. Both taxa belong to an endemic European clade of dryolestids, including also Achyrodon and Phascolestes from the earliest Cretaceous (Berriasian) of England. Despite its greater geological age, Hercynodon gen. nov. is the most derived representative of that clade, indicated by the complete reduction of the metacone. The discrepancy between derived morphology and geological age may be explained by an increased rate of character evolution in insular isolation. Other insular phenomena have earlier been observed in vertebrates from the Langenberg Quarry, such as dwarfism in the small sauropod Europasaurus, and possible gigantism in the morganucodontan mammaliaform Storchodon and the pinheirodontid multituberculate mammal Teutonodon which grew unusually large.

巴特哈尔茨堡附近的朗伯格采石场生产了德国的第一个侏罗纪茎部兽类哺乳动物，从欧洲群岛下萨克森盆地古岛海岸沉积物附近的基米迪吉安（侏罗纪晚期）恢复。新的茎therian以一个较低的和三个较高的臼齿为代表。赫尔希诺顿gen。等 十一月 这归因于Dryolestidae，这是一组从前侏罗纪到白垩纪早期在劳拉西亚西部普遍存在的tribosphenic冠类哺乳动物。新的分类单元的特点是体积小，上臼齿缺乏麦角锥的减少的尖瓣模式，以及剪牙冠旁cri和后cri的增强。系统发育分析确定了Hercynodon gen。十一月 作为Crusafontia的姊妹分类单元来自西班牙的下白垩统（巴雷米亚）。这两个类群都属于欧洲地方的类固醇类，其中也包括英格兰最早的白垩纪（贝里亚斯族）的Achyrodon和Phascolestes。尽管其地质年龄较长，但赫尔希诺顿（Hercynodon gen）十一月 是该进化枝的最派生代表，由元圆锥的完全还原表示。导出的形态与地质年龄之间的差异可以用岛状隔离中性状进化的速率增加来解释。早在Langenberg采石场的脊椎动物中就观察到了其他岛状现象，例如小型蜥脚类欧洲龙的侏儒症，以及摩根科顿滩哺乳动物形式的Storchodon的巨型现象。以及长得异常大的长鼻类多结节哺乳动物Teutonodon。