Microporella bicollaris sp. nov. from the Ionian Sea A, B, F Gulf of Taranto, Porto Cesareo MPA, sample PCE 10 Holotype, PMC. B29a. 20.11.2020 C, D SE Sicily, Plemmirio MPA, Mazzere cave, Paratype PMC. B29b2. 20.11.2020 E, G Gulf of Taranto, Porto Cesareo MPA, sample PCI 10, Paratype, PMC. B29b1. 20.11.2020 A two colonies nearly completely covering subsequent segments of the green alga Halimeda tuna B peripheral colony portion, showing the transition from the older autozooids (ovicellate, bottom right) to younger autozooids (non-ovicellate, top left) C group of autozooids, one with six oral spine bases (centre left) D close-up of two ovicellate zooids with the typical personate ovicell forming a collar bridge between the orifice and the ascopore E close-up of the orifice with five spine bases and smooth hinge-line with two rectangular condyles at corners F unbleached group of ovicellate autozooids with well-developed collars and avicularian mandibles G group of bleached autozooids, some ovicellate, fouled by algae. Note the collar developing from converging lateral lappets, the vizor-like band of gymnocystal calcification leaving visible the proximalmost pair of oral spines. Scale bars: 1 mm (A); 500 µm (B, C, F); 200 µm (D, G); 100 µm (E).