Geragnostella, Geratrinodus, Neptunagnostella Geragnostus is a genus of very small agnostid trilobites whose fossils are found Ordovician-aged marine strata from Eurasia, North America and Argentina.

[4] Unidentified species in the genus Geragnostus have among others been found in Colombia (Guaviare River, Meta).

[7] Like all Agnostida, Geragnostus is diminutive, with the headshield (or cephalon) and tailshield (or pygidium) of approximately the same size (or isopygous) and outline.

The glabella is about 2⁄3 times the length of the cephalon, and its sides are very gently tapered forward, with a broadly rounded front, and is well defined by shallow furrows and an abrupt change in exoskeletal slope.

The border is moderately wide, gently convex, defined by a shallow furrow, and widest at the rear corners which carry a pair of strong, backwardly directed spines.