Tretosina, Canu & Bassler, 1927

Sonar, Mohan A., Pawar, Ravi V. & Wayal, Dnyaneshwar V., 2022, Newly discovered species of cheilostomatid Bryozoa from the Miocene of western Kachchh, Gujarat, India, European Journal of Taxonomy 821, pp. 16-39 : 31

? Tretosina gen. et sp. indet.

Fig. 10 ; Table 9

Material examined

INDIA • 11 specs; yellow limestone of the south of Walaram Tirth Dham near Murachbann , Aquitanian, lower Miocene, Kharinadi Formation; 23°39′15″ N, 68°58′02″ E; Jan.–Feb. 2012; Pawar leg.; GIS/B 0522 to 0532 .

Description

Colony erect with six zooidal series. Zooids hexagonal, arranged quincuncially in alternating longitudinal rows, bordered by thin raised, smooth mural rim ( Fig. 10A ). Opesia oval, less than ½ length of the zooid. Cryptocyst tuberculated, descending into the opesia narrowing proximally. Distal arch smooth, thin and raised ( Fig. 10B ). Spines, avicularia and ooecia not observed.

Remarks

In these Kachchh specimens, the median cryptocystal process and ooecium typical of Tretosina were not observed making even genus-level attribution difficult. So, the genus is left in open nomenclature until better preserved material is available.

Figures

Fig. 10.?Tretosina gen. et sp. indet. (GIS/B 0522). A. General view of the colony showing hexagonal autozooid arranged in longitudinal rows. B. Close-up of a single autozooid showing oval opesia and tuberculated cryptocysts.