Thalamoporella arabiensis Guha & Gopikrishna, 2004

Sonar, Mohan A., Pawar, Ravi V. & Wayal, Dyaneshwar V., 2022, Fossil Thalamoporellidae (Bryozoa) from Paleogene-Neogene sediments of western Kachchh, Gujarat, India, Zootaxa 5104 (2), pp. 251-274 : 258-259

Thalamoporella arabiensis Guha & Gopikrishna, 2004

( Fig. 7 , Table 4)

Thalamoporella arabiensis Guha & Gopikrishna, 2004: 18 , fig. 13. Non Thalamoporella arabiensis Amui & Kaselowsky, 2006: 12 , figs 10–14.

Material examined. GIS/B 0153–0182. Yellowish limestone at cliff section of Lakdi Nadi near Tera village , Chhasra Formation , late lower Miocene (Burdigalian), 23°23’19’’ N, 68°58’10’’ E, elevation 52–56 m, 15 January 2011, DST project, New Delhi .

Description. Colony encrusting, unilaminar. Autozooids long, slender, somewhat vasiform, being broader in middle with convex lateral margins, tapering proximally and distally ( Fig. 7A ). Autozooids arranged quincuncially in longitudinal series, each with distinct raised granular autozooidal margin. Orifices small, D-shaped, much raised distally with thick arched rim and straight or weakly concave proximal margin. Two small adoral tubercles present on each side of aperture. Opesiules small, oval, equal in size, placed near proximal edge of orifice away from lateral margins. Cryptocystal shelf well developed, shallow, densely perforated with moderately large pores. Avicularia present at bifurcation of rows, torqued towards distal zooid ( Fig. 7B ); avicularium almost 70% of autozooid length, with long acute rostrum tapering distally, rounded proximally, proximal part of cystid with wide, granular cryptocyst. Kenozooids also developed in colony, similar to autozooids in length and width ( Fig. 7C ). Ovicells not observed.

Remarks. Thalamoporella arabiensis Amui & Kaselowsky, 2006 from the Gulf of Aden is a junior homonym and needs a new name. It differs from the Kachchh species in having bilaminar branches and no avicularia or adoral tubercles; orifices are nearly circular with small condyles.

Figures

FIGURE 7. Thalamoporella arabiensis Guha & Gopikrishna, 2004 (GIS/B 0153). A. General view of autozooids, orifices and an avicularium. B. Detail of autozooids, orifices and avicularia. C. The portion of a colony showing kenozooids. Scale bars: A, 500 µm; B, 200 µm; C, 500 µm.