The genus Aulacoseira is cosmopolitan and often abundant in fresh waters. In Costa Rica, freshwater diatom surveys have been restricted to flowing waters, aside from our own explorations. Among sediment samples from some 90 lakes we have encountered an undescribed species which we herein propose to name Aulacoseira umanai Haberyan sp. nov. In this species, the face of larger valves often bears ridges and tubercles (knobs); separation spines are short (<2.3 µm) and longer spines are absent. The ringleiste is thick, solid, and very wide. This, in combination with its short collum, distinguishes A. umanai from many other species of the genus. Aulacoseira umanai is abundant in the surficial sediments of multiple glacial lakes that are over 3450 m in elevation on Cerro Chirripó; it is also abundant in glacial-age deposits in La Chonta bog (2310 m a.s.l.). It seems to have evolved from an ancestor that resembled A. alpigena; the locality of this event is unknown but was likely to have been a high-altitude lake in the Central American isthmus.

中文翻译：

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在哥斯达黎加高原发现一种未描述的 Aulacoseira 物种

Aulacoseira属是世界性的，通常在淡水中丰富。在哥斯达黎加，除了我们自己的探索之外，淡水硅藻调查仅限于流动水域。在来自大约 90 个湖泊的沉积物样本中，我们遇到了一种未描述的物种，我们在此建议将其命名为 Aulacoseira umanai Haberyan sp。十一月 在这个物种中，较大的瓣膜通常带有脊和结节（节）；分离刺很短 (<2.3 µm)，没有更长的刺。Ringleiste 很厚，很结实，而且很宽。这与它的短颈相结合，将 A. umanai 与该属的许多其他物种区分开来。Aulacoseira umanai 在 Cerro Chirripó 海拔超过 3450 m 的多个冰川湖的表层沉积物中含量丰富；在 La Chonta 沼泽 (2310 m a. sl)。它似乎是从类似于 A. alpigena 的祖先进化而来的；这次事件的地点未知，但很可能是中美洲地峡的一个高海拔湖泊。