Abstract

A new monosulcate species, Shanbeipollenites lagarcitensis sp. nov. is described from the Lower Cretaceous Lagarcito Formation, Sierras de Guayaguas (north-western San Luis Basin), Argentina. Shanbeipollenites lagarcitensis shares with other species of this genus a broadly ellipsoidal outline and a diagonally disposed distal sulcus. However, the new species differs from the psilate type species Shanbeipollenites quadrangulatus and from S. quadratus by the presence of sculptural elements distributed at the equatorial region, close to the opposite ends of the sulcus. The thicker wall, exine separation, much more strongly diagonal offset of the sulcus and the rugulate-verrucate sculpture with an equatorial distribution close to the opposite ends of the sulcus, distinguish this new species and expands the concept of the genus Shanbeipollenites. The presence of two separate exine layers supports its gymnosperm affinity. Furthermore, the occurrence of Shanbeipollenites lagarcitensis in the Albian Lagarcito Formation from mid–latitudes, central–western Argentina constitutes the youngest record of the genus worldwide. This new record expands the biostratigraphical range of the taxon into the Albian.

摘要

一个新的单槽物种，山北花粉。十一月 来自阿根廷的 Sierras de Guayaguas（圣路易斯盆地西北部）的下白垩统 Lagarcito 组。Shanbeipollenites lagarcitensis与该属的其他物种共享一个宽椭圆形轮廓和一个对角布置的远端沟。然而，该新种不同于甲藻型种山北花粉和方斑花粉。通过分布在赤道地区的雕塑元素，靠近沟的两端。较厚的壁、外壁分离、沟的更强烈的对角偏移以及靠近沟两端的赤道分布的皱纹-疣状雕刻，区分了这个新物种并扩展了山北花粉属的概念。两个独立的外壁层的存在支持其裸子植物亲和力。此外，阿根廷中西部中纬度Albian Lagarcito组中山北花粉的出现构成了世界上最年轻的该属记录。这一新记录将分类群的生物地层范围扩展到阿尔比斯。