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| Microcorona girodi Gale & Jagt, 2026 |
A tiny, sessile brachylepadid barnacle, Microcorona girodi gen. et sp. nov., is described from lower and upper Campanian chalks of the Hannover area (northern Germany) and upper Maastrichtian biocalcarenites of southern Limburg (the Netherlands). The new taxon possesses a fused wall, comprising a rostrum, a carina, paired marginal plates and surrounding imbricating plates; an upper latus is absent. Cladistic analysis supports the interpretation that the new taxon is a sister group to all post-Mesozoic balanomorph barnacles (Neobalanomorpha). In the Hannover area, the new brachylepadid encrusted brachiopod shells, echinoid tests and serpulid tubes in a deep water (>200 m) habitat. The single specimen from the upper Maastrichtian of the southern Netherlands was bioimmured by an exogyrine oyster in a shallow-water (<50 m) setting, thus demonstrating that early balanomorphs were able to occupy a wide range of habitats.
Key words: Cirripedia; Balanomorpha; Chalks; Biocalcarenites; Germany; The Netherlands.
Order Balanomorpha Pilsbry, 1916
Family Brachylepadidae Woodward, 1901
Microcorona gen. nov.
Type species: Microcorona girodi gen. et sp. nov.
DIAGNOSIS: Tiny (R-C < 2 mm), low, oval-subrhombic shell made up of fused carina, two marginal plates and rostrum. The carina overlaps the marginal plates, which in turn overlap the rostrum. Two or three tiers of triangular-rectangular imbricating plates, fused to wall. Scutum triangular, elongated, tergum short, equilaterally triangular. Upper latus absent.
DERIVATION OF NAME: Latin micro-, meaning tiny, and corona meaning crown, in allusion to the size and shape of the shell.
REMARKS: Microcorona girodi gen. et sp. nov. possibly evolved from Epibrachylepas or a closely related genus by the development of imbricate articulations between the marginals, carina and rostrum, and fusion of these plates, plus the surrounding imbricating plates. In the opercular valves, the upper latus was lost.
Microcorona girodi gen. et sp. nov.
Derivation of name: Named after Dr. Peter Girod (Berlin), who collected the holotype and presented this to the Museum für Naturkunde (Leibniz Institut, Berlin).
Andrew Scott GALE, and John W.M. JAGT. 2026. A new basal balanomorph cirripede (Thoracica, Brachylepadidae) from the Upper Cretaceous and its bearing on the evolutionary origins of the group. Acta Geologica Polonica. 76(1), e68. DOI: doi.org/10.24425/agp.2026.158182
































