Dybowskiella hupehensiformis, Ernst, 2016

Ernst, Andrej, 2016, Bryozoan fauna from the Permian (Artinskian-Kungurian) Zhongba Formation of southwestern Tibet, Palaeontologia Electronica (1946) 51 (9), pp. 1-59 : 7-9

Dybowskiella hupehensiformis n. sp.

Figure 4.3-7 ; Table 4

zoobank.org/ 4DE81E30-ACFA-4160-91CF-A7E59260D862

1983 Dybowskiella hupehensis Yang, 1956 ; Yang and Lu, p. 266, pl. 9, figs. 1-4.

Etymology. The species is named after the species Dybowskiella hupehensis Yang, 1956 because of its close similarity.

Holotype. SMF 23.030 .

Paratypes. SMF 23.031 – SMF 23.035 .

Type locality. Zhongba area of southwestern Tibet (E 84.31536, N 29.74233) .

Type stratum. Zhongba Formation, Permian (upper Cisuralian–Guadalupian).

Diagnosis. Encrusting colony; diaphragms few to absent; lunaria well-developed, horseshoe-shaped; apertures separated by 1–2 rows of vesicles; 11–15 vesicles surrounding each aperture; maculae consisting of vesicular skeleton.

Description. Encrusting, partly multilayered colony, separate sheets 1.15–1.75 mm thick. Autozooecia growing from thin epitheca, bending in the early exozone to the colony surface. Autozooecial diaphragms few to absent. Autozooecial apertures circular to oval. Lunaria well-developed, horseshoe-shaped, directed towards the next macula, disappearing in deeper sections; ends of lunaria indenting into autozooecia. Vesicles small to medium in size, high, separating autozooecia in 1– 2 rows, 11–15 surrounding each autozooecia aperture, with rounded to flat roofs, polygonal in tangential section. Autozooecial walls granular prismatic, 0.005 –0.015 mm thick. Maculae consisting of vesicular skeleton, 0.9–1.3 mm in diameter.

Remarks. Dybowskiella hupehensiformis n. sp. resembles the species described as Dybowskiella hupehensis Yang, 1956 by Yang and Lu (1983) from the Lower Permian Baliqliq Group of Kalpin in Western Xinjang, China. However, D. hupehensis Yang, 1956 , originally described from the Chihsia Formation (Lower Permian, Artinskian–Kungurian) of Hupei, China, has significantly larger autozooecial apertures than the species described by Yang and Lu (1983) (aperture width 0.34–0.42 mm vs. 0.26–0.36 mm in the material of Yang and Lu). Dybowskiella hupehensiformis differs insignificantly from the material of D. hupehensis Yang, 1956 described by Yang and Lu (1983): aperture width 0.26–0.33 mm vs. 0.26–0.36 mm, and aperture spacing 0.45–0.67 mm vs. 0.35–0.50 mm.

Dybowskiella hupehensiformis n. sp. is similar to the species Dybowskiella sp. described by Yang and Lu (1983) from the Baliqliq Group of Kalpin in Western Xinjang, China (aperture width 0.26–0.33 mm vs. 0.30–0.33 mm in Dybowskiella sp. ; aperture spacing 0.45–0.67 mm vs. 0.38–0.64 mm in Dybowskiella sp. ). Furthermore, D. hupehensiformis differs from D. crescens ( Crockford, 1944) from the Lower Permian (Artinskian) of Western Australia in smaller autozooecial apertures (aperture width 0.26–0.33 mm vs. 0.29–0.43 mm in D. crescens ).

Occurrence. Baliqliq Group, Lower Permian ; Kalpin, Western Xinjiang, China . Zhongba Formation, Permian ( upper Cisuralian –Guadalupian); Zhongba area of southwestern Tibet .

Figures

FIGURE 4. Thin section photographs of Fistulipora sakagamii n. sp., holotype SMF 23.028 (1 and 2); Dybowskiella hupehensiformis n. sp., holotype SMF 23.030 and paratype SMF 23.032 (3–7); and Fistuliramus xianzaensis Liu and Wang, 1987, SMF 23.037 (8). 1, 2, 5–7, tangential section showing autozooecial apertures and vesicles; 3 and 4, longitudinal section showing autozooecial chambers and vesicular skeleton; and 8, branch transverse section.

FIGURE 5. Thin section photographs of Fistuliramus xianzaensis Liu and Wang, 1987, SMF 23.042 (1) and SMF 23.038 (2 and 3); and Eridopora uncata Yang and Lu, 1983, SMF 23.052 (4 and 6) and SMF 23.051 (5). 1, longitudinal section; and 2–6, tangential section showing autozooecial apertures and vesicles.

FIGURE 6. Thin section photographs of Eridopora uncata Yang and Lu, 1983, SMF 23.052 (1–3); Cyclotrypa alexanderi Sakagami, 1963 SMF 23.056 (4–5), SMF 23.061 (6), and SMF 23.056 (7); and Hexagonella kobayashii Sakagami, 1968, SMF 23.069 (8–9) and SMF 23.070 (10 and 11). 1–3, tangential section showing autozooecial apertures with lunarial ends indenting into the aperture (arrow); 7, tangential section showing autozooecia and macrozooecia (arrow); 8 and 9, branch transverse section showing autozooecial chambers and vesicular skeleton; and 10 and 11, longitudinal section showing autozooecial chambers and vesicular skeleton.

FIGURE 7. Thin section photographs of Hexagonella kobayashii Sakagami, 1968, SMF 23.067 (1–3) and SMF 23.072 (4); and Goniocladia aff. indica Waagen and Pichl, 1885, SMF 23.266 (5), SMF 23.077 (6), and SMF 23.073 (7). 1–3 and 6, tangential section; 7, mid-tangential section showing autozooecial chamber; 4, transverse section showing mesotheca with median tubules (arrow); and 5, external view of the colony form the reverse side.