Thalamoporella bhujensis, Sonar & Pawar & Wayal, 2022

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 : 256-257

Thalamoporella bhujensis n. sp.

( Fig. 6 , Table 3 )

Material examined. Holotype: GIS/B 0131 ; Paratypes: GIS/B 0132–0152. Yellowish limestone west of Haripar, Kharinadi Formation , lower Miocene (Aquitanian), 23°22’08’’ N, 68°49’40’’ E, elevation 20 m, 12 January 2011, DST project, New Delhi .

Etymology. The species is named after the ‘Bhuj’ district of Kachchh region, Gujarat.

Diagnosis. Colony erect,cylindrical with dichotomously branching stems.Autozooids rectangular,in longitudinal series, bordered by thick raised autozooidal boundaries. Orifices subcircular. Adoral tubercles present. Opesiules subrounded, equal in size. Cryptocyst granular, perforated. Avicularia asymmetrical with subacute rostrum directed distolaterally. Ovicells not observed.

Description. Colony erect, cylindrical, stems dichotomously branching, circular in cross-section. Autozooids generally elongate-rectangular, arranged quincuncially in longitudinal series, with parallel or slightly convex lateral margins, bordered by distinct, thick, raised, smooth-rimmed autozooidal boundaries, fused with those of adjacent autozooids ( Fig. 6A ). Orifices subcircular, longer than wide, with raised rim, distal border arcuate, proximal margin concave. Adoral tubercles large, raised, on opposite sides of orifice. Two subrounded, equal opesiules adjacent to lateral walls of autozooids away from proximal lip of orifice. Cryptocyst sunken below level of autozooidal rim, granular with coarse perforation. Avicularia asymmetrical, c. 60% of autozooid length, rostrum subacute with blunt tip, directed distolaterally away from sibling zooid; opesia elongate-oval, c. 50% of avicularian length; cryptocyst granular, developed around opesia laterally and proximally ( Fig. 6B ). Ovicells not observed.

Remarks. This species has distinctive asymmetrical avicularia directed away from the sibling zooid. It differs from related Thalamoporella falcifera (Hincks, 1880) , which has strongly curved avicularia with an acute tip (see Soule et al. 1999, p. 8, fig. 6).

Figures

FIGURE 6. Thalamoporella bhujensis n. sp. (Holotype GIS/B 0131). A. General view of colony showing autozooids. B. Detail of the autozooids, orifices and an avicularium. Scale bars: A, 500 µm; B, 100 µm.