Tricephalopora Lang, 1916

Martino, Emanuela Di & Rosso, Antonietta, 2015, Revision of the bryozoan genus Gephyrotes Norman, 1903 (Cheilostomata, Cribrilinidae) with the description of two new taxa, Zootaxa 3941 (2), pp. 261-283 : 274-275

Genus Tricephalopora Lang, 1916

Revised diagnosis. Zooids with typically paired adventitious avicularia lateral to orifice, these often extending across its margin at a variable position and contributing to the formation of the peristomial rim, or projecting into the secondary orifice and affecting its shape. Frontal shield visible only medially as peripheral area surrounded and covered by thick skeletal calcification associated with interzoooidal kenozooids; costae lacking intercostal bridge and separated by a single, large, intercostal pore; raised peristomial rim formed by a band of calcification seemingly partially derived from kenozooids.

Type species. Cribrilina triceps Marsson, 1887 .

Remarks. The genus Tricephalopora shows affinities with Gephyrotes in general aspect, particularly in the raised, collar-like peristomial structure and the highly developed kenozooidal network. However, the peristomial constructions are formed differently in the two genera—they result from kenozooidal secondary calcification in Tricephalopora but from the bifurcation of the distalmost pair of costae in Gephyrotes . Further differences are seen also in the degree of kenozooidal development. In Tricephalopora , kenozooids are responsible for a massive spread of secondary calcification, lacking frontal openings, that covers much of the zooidal frontal shield, leaving only a reduced window exposed, whereas kenozooids in Gephyrotes are strictly interzooidal, and narrow and tubular with numerous openings. Their overall general similarity caused the inclusion in Gephyrotes of several species that better conform to Tricephalopora . Taylor & McKinney (2006) first transferred Gephyrotes lamellaria Canu & Bassler, 1926 to Tricephalopora , and further species are here assigned to this genus.

Distribution. Coniacian–Thanetian of Europe and North America ( Fig. 1 ).

Figures

FIGURE 1. Map showing the spatial and temporal distribution of all the studied species. 1, Gephyrotes nitidopunctatus (Smitt, 1868); 2, Gephyrotes fortunensis Pouyet, 2000; 3, Gephyrotes moissettei n. sp.; 4, Gephyrotes spectabilis Canu & Bassler, 1920; 5, Gephyrotes quadriserialis Canu & Bassler, 1920; 6, Gephyrotes convexus Canu & Bassler, 1920; 7, Tricephalopora saillans (Canu & Bassler, 1920); 8, Tricephalopora levigata (Canu & Bassler, 1920); 9, Spiniflabellum spinosum Canu & Bassler, 1928. Open circles, Recent; solid circles, Miocene; diamond, Oligocene; stars, Eocene; triangles, Danian.