Fig. 2 (11)
Diagnosis: Paries exteriorly with protuberances.
Etymology: Morphological, alluding to protuberances (nod in Latin) of the paries;
Occurrence: Pauvrelay (Paulmy commune), Indre-et-Loire, France; faluns of Middle Miocene age.
Material: Holotype: MNHN A 25755 right lateral plate.
Measurements: Holotype, MNHN A 25755: height of the middle of the plate 1.8 mm.
Description: Colour ivory. Paries exteriorly with small protuberances on growth ridges. Parietal tubes in single row. Longitudinal septa of parietal inner lamina with lateral denticles. Sheath with lateral margin not extended. Radius solid with very oblique upper edge, sutural edge with smooth teeth, inner face without longitudinal abutment. Ala with secondary alar increment, summit oblique, sutural edge septed.
Affinities: Among the Balanoidea, barnacles with calcareous projections were restricted to the Acastinae Kolbasov, 1993 and the Megabalaninae Newman, 1979. Balanus nodulus sp. nov. is the first Balaninae, found with this pattern.