Canutrypa, BASSLER, 1952

Ernst, Andrej, Tolokonnikova, Zoya & Yarahmadzahi, Hamed, 2012, Upper Devonian (Frasnian) Bryozoa from the Shishtu 1 Formation of Niaz area (eastern Tabas, central Iran), Revue de Paléobiologie 31 (1), pp. 1-14 : 3

Canutrypa hemispheroidea (YANG, 1954)

Pl. I, figs. 1-12; Table 1

1954. Fistulipora hemispheroidea YANG, p. 210, pl. 1, figs 4a-b.

1962. Fistulipora hemispheroidea YANG, 1954. – YANG & LU, p. 11-12, pl. 2, figs 1a-c.

1991. Canutrypa francqana BASSLER, 1952. – BIGEY, p. 27, pl. 1, figs 12-13 [non figs 1-8],

1991. Fistuliporid. – BIGEY, p. 27, pl. 1, figs 9-11.

Material: Seventeen thin sections of five colonies SMF 21.081- SMF 21.099.

Description: Encrusting multilayered and solid subramose colonies. Single sheets 0.55-1.80 mm thick. Encrusting multilayered colonies up to 35 mm thick, subramose colonies 25-50 mm in diameter and 45- 110 mm in height. Autozooecia tubular, having circular to oval apertures; in subramose colonies long, growing parallel to branch axis, curving gently in exozone; in encrusting colonies and secondary overgrowths long to short, originating from a thick epitheca, curving gently to the colony surface. Autozooecial diaphragms few to abundant throughout the colony, thin, straight or inclined. Lunaria indistinct, triangular to horseshoe shaped, occurring only in uppermost parts of autozooecia. Vesicles polygonal in cross section; wide, high and irregularly shaped in endozones and maculae, becoming narrow and flat at colony surface, sealed by granular skeleton at colony surface, 9-17 surrounding each autozooecial aperture. Hemicylindrical cystlike structures in many autozooecia in exozone, positioned directly on autozooecial walls, usually at distal parts of autozooecial chambers in exozone, rare to absent in endozones, 0.22-0.30 mm wide. Cyst wall consisting of prismatic calcite crystals oriented with their axes perpendicular to the wall plane, 0.03-0.04 mm thick. Incomplete cysts often occurring. In some cysts small pores in apical parts observed, 0.025 -0.040 mm in diameter. Autozooecial walls granular-prismatic, 0.010 - 0.015 mm thick in endozones; granular, 0.03-0.04 mm thick in exozones. Colony surface covered with thick layer of granular skeleton. Maculae consisting of elevated central cluster of large and irregularly shaped vesicles surrounded by larger autozooecia, 1.0- 2.3 mm in diameter regularly spaced 4.0- 5.8 mm from centre to centre.

Remarks: Canutrypa hemispheroidea (YANG, 1954) differs from C. francqana BASSLER, 1952 in possessing larger autozooecial apertures (average aperture width 0.33 mm vs. 0.21 mm in C. francqana) and larger distance between aperture centres (average distance between aperture centres 0.42 mm vs. 0.31 mm in C. francqana). Measurements for C. francqana BASSLER, 1952 are from ERNST (2008).

Occurrence: Wutsun Shale, Middle Devonian; Kwangsi, China. Devonian; Qilianshan, China. Hajigak Formation, Upper Devonian (Frasnian); Hajigak, central Afghanistan. Shishtu 1 Formation, Upper Devonian (Frasnian); Niaz section, eastern Tabas, central Iran.