Genus Luminocanthus n. gen. urn:lsid:zoobank.org:act: 872DDF1A-35F0-4369-9812-7B1D5A0DF8F7 TYPE SPECIES. — Luminocanthus plenilutetiensis n. sp. DERIVATIO NOMINIS. — Refers to the bright outer rim of these fairly thick circular coccoliths (luminus = light, canthus = ‘rim of the wheel’), when viewed in cross-polarized light. DIAGNOSIS. — This new genus is erected to include circular coccoliths consisting of a non-perforated, practically closed, central disk and a much smaller outer rim with many slightly bent elements (n> 30). The outer rim is always highly birefringent in cross-polarized light, the central disk sometimes (e.g. in the type species). DISCUSSION Four species are currently included in this genus (in stratigraphical order): L. eolutetiensis n. gen., n. sp. from the lowermost Lutetian of the Belgian Basin (see below), L. plenilutetiensis n. gen., n. sp. from the lower middle Lutetian of the Belgian Basin and the Paris Basin (see below), L. hirsitus (Müller, 1970) n. comb. from the lower middle Oligocene of Belgium and Germany (Müller 1970; Steurbaut 1986) and L. hoerstgensis (Müller, 1970) n. comb from the upper middle Oligocene of Northern Germany (Müller 1970). Both Oligocene species have been synonymized with the upper Eocene species Cribrocentrum reticulatum (Gartner & Smith, 1967) (cf. Nannotax 3, http://www.mikrotax.org/Nannotax3/index. html), although erroneously, as these taxa are fundamentally different (e.g. in construction of distal shield and number of elements in the shields).

Published as part of Steurbaut, Etienne & Nolf, Dirk, 2021, The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP, pp. 311-363 in Geodiversitas 43 (11) on page 344, DOI: 10.5252/geodiversitas2021v43a11, http://zenodo.org/record/4891107