Acdalopora sokolovi Bondarenko, 1958

Cui, Yu-Nong & Wang, Guang-Xu, 2023, Early Katian, Late Ordovician, heliolitine corals from southern Kuruktag in northeastern Tarim Basin of China, Acta Palaeontologica Polonica 68 (2), pp. 273-295 : 286-290

publication ID	https://doi.org/ 10.4202/app.01023.2022
persistent identifier	https://treatment.plazi.org/id/03F35C14-FF80-FFB0-885B-FA3680574579
treatment provided by	Felipe
scientific name	Acdalopora sokolovi Bondarenko, 1958
status

Treatment

Figs. 11 View Fig , 12 View Fig .

1958 Acdalopora sokolovi sp nov.; Bondarenko 1958: 216, pl. 5: 1–3. 1964 Acdalopora sokolovi Bondareko 1958 ; Kovalevsky 1964: 41, pl.

2: 2.

non 1975 Acdalopora sokolovi Bondareko 1958 ; Leleshus 1975: 11, 12, pl. 4: 1, 2.

non 1978 Acdalopora sokolovi Bondareko 1958 ; Kim and Apekin 1978: 62, 63, pl. 6: 1.

1986 Acdalopora sokolovi Bondarenko, 1958 ; Lin and Wang 1986: 49, pl. 7: 4a, 4b.

?1986 Acdalopora junggarensis sp nov.; Lin and Wang 1986: 48, pl. 6: 1a, 1b.

2012b Acdalopora sokolovi Bondarenko, 1958 ; Ospanova 2012b: 33, pl. 7.

Material.—Eight sectioned specimens, NIGP 201005–201012 from the Yuanbaoshan Formation (lower Katian) of southern Kuruktag, Tarim Basin, China.

Emended diagnosis.—Species of Acdalopora with TaDs 0.62–1.59 mm. Corallite walls wavy. Septa long; mostly laminate, with spines developed near the axial ends. Tabulae complete, horizontal.

Description.—Five complete coralla are measured, of low domical or columnar form, with the largest 123.61 mm wide and 35.42 mm high, and the smallest 44.88 mm wide and 13.08 mm. Corallites slightly stellate, TaDs 1.18–1.59 mm (average 1.34 mm). Corallite walls complete, moderately crenulated, 0.06–0.12 mm thick (average 0.08 mm). Each corallite having 12 long septa. Septa 0.15–0.36 mm long (average 0.27 mm), tapering toward the axis; mostly laminate, with spines developed near the axis. Tabulae complete, sub-horizontal or slightly convex, Ta5 14–16. Spacing of corallites variable, often in contract or slightly separated, with their centers 1.57–2.33 mm apart (average 1.91 mm). Coenenchyme consisting of overlapping small domed dissepiments. The width of the smaller and larger dissepiments 0.10–0.21 mm (average 0.13 mm), and 0.23–0.36 mm (average 0.27 mm), respectively. Dissepiments 20–22 per 5 mm.

Remarks.—These specimens are most likely conspecific with the type material of Acdalopora sokolovi Bondarenko, 1958 , from the Upper Ordovician Dulankara Formation of the Chu-Ili Terrane in southern Kazakhstan, differing only in having slightly smaller corallite size (0.62–1.35 mm) of the latter. This type material was refigured by Ospanova (2012a).

The material described by Lin and Wang (1986) as Acdalopora sokolovi is from the Upper Ordovician Bulongor Formation of Hobuksar in northwestern Xinjiang. It is essentially identical to the holotype of A. sokolovi , except only in its denser tabulae (20–24 per 5 mm). Acdalopora junggarensis Lin and Wang, 1986 , recorded from the same locality and horizon is a probable synonym of A. sokolovi , which differs only in having a slightly larger corallite size 1.2–1.7 mm in diameter), and more convex tabulae.

Specimens identified as A. sokolovi are also known from the Upper Ordovician of Zeravshan Ridge, Tajikistan Leleshus 1975), and the Archalyk Member (upper Katian) of the Shakhriomon area in Uzbekistan ( Kim and Apekin 1978). They have smooth and incomplete corallite walls and inconsistent septal number, and were referred to Acdalina asiatica by Ospanova (2012b), which is followed in this study.

The diagnosis of A. sokolovi is revised herein based on all the material now assigned to this species, with major revisions including an extension of the range of corallite size (0.62–1.59 mm), and major revisions including an addition of the development of septal spines. Its comparison with similar species is shown in Table 4 and discussed below. A. mira Chekhovich, 1977 , from the Upper Ordovician Hondell Bed of western Tuva strongly resembles A. sokolovi in corallite size and septal development. The main differences lie in less developed septal plates and better developed coenenchyme of the former. Acdalopora qiakuertensis Lin and Wang, 1985 , from the Upper Ordovician Gabosar Formation of Gabosar in northern East Junggar, Xinjiang, also show similarities to A. sokolovi in many aspects, but is distinguished by having shorter septal plates, as well as complete and slightly concave tabulae. Acdalopora breviana Yu, 1960 , from the Upper Ordovician (probably Sanqushan Formation of late Katian age) of Jiangxi, southeastern China, has similarly well-developed septal spines. It differs from the present material in having slightly larger corallite size (1.5–1.75 mm in diameter), shorter septa and more convex tabulae.

Stratigraphic and geographic range.—The Yuanbaoshan Formation (lower Katian) of southern Kuruktag, northeastern Tarim, China; the Dulankara Formation (lower Katian) of the Chu-Ili Terrane, southern Kazakhstan; the Bulongor Formation (Katian) of Hobuksar, northwestern Xinjiang, China; the Upper Ordovician of Chingiz Range, Kazakhstan.

Family Pseudoplasmoporidae Bondarenko, 1963

Genus Navoites Leleshus and Ospanova, 1979

Type species: Navoites simmetricus Leleshus and Ospanova, 1979 , Upper Ordovician , Zeravshan-Gissarskiy mountain, Tajikistan .

Remarks.—The revised concept of Navoites proposed by Wang et al. (2020) is accepted herein.

Navoites irregularis ( Lin and Chow, 1977) Figs. 13 View Fig , 14 View Fig .

1977 Heliolites sinensis irregularis sp nov.; Lin and Chow 1977: 181, 182, pl. 52: 7a, 7b, not pl. 52: 5a, 5b.

2015 Heliolites sinensis irregularis Lin and Chow, 1977 ; Dai et al. 2015: 52, pls. 47, 48: 7E, 8E.

?2017 Heliolites sinensis irregularis Lin and Chow, 1977 ; Han et al. 2017: pl. 15: 6.

Material.—Three sectioned specimens, NIGP 201013–201015 from the Yuanbaoshan Formation (lower Katian) of southern Kuruktag, Tarim Basin, China.

Emended diagnosis.— Navoites with TaDs 0.73–1.15 mm. Corallite walls thin. Septa short. Tabulae complete, sub-horizonal or slightly convex, Ta5 14–16. Corallites commonly separated by 2–4 rows of tubules. Tubular walls incomplete. Diaphragms complete, flat, slightly sagging or convex, 22– 24 per 5 mm.

Description.—Three almost complete coralla are measured, of low domical form, with the largest 50.46 mm wide and 21.92 mm high, and the smallest 27.21 mm wide and 21.92 mm. Corallites rounded or sub-rounded, TaDs 0.82– 0.96 mm (average 0.92 mm). Walls complete, slightly faceted, WT 0.03–0.09 mm (average 0.05 mm). Septa numbering 12, short, extending one-ninth the TaD. The width of septa 0.11–0.16 mm (average 0.14 mm). Tabulae complete, slightly convex, Ta5 15–16. Corallites commonly separated by 2–4 rows of tubules, with centers 1.13–1.86 mm apart (average 1.54 mm). Tubules having 5 or 6 sides, 0.32 –0.37 mm in diameter, with 12 surrounding each corallite. Tubular walls incomplete, commonly 0.04–0.05 mm thick. Diaphragms generally complete, flat, slightly sagging or convex, mostly 24 per 5 mm.

Remarks.—Specimens clearly conspecific with the present material were identified by Lin and Chow (1977) as Heliolites sinensis irregularis , from the middle Sanqushan Formation (upper Katian) of Jiangxi, southeastern China. Their major difference lies in the slightly larger corallites (1.00– 1.15 mm in diameter) of the former, and we therefore assign our material to this species. The original generic assignment of H. sinensis irregularis was based on its tubular coenenchyme. We assign this species to Navoites because of the consistent presence of 12 coenenchymal tubules ( Dixon and Jell 2012; Zhen et al. 2017; Wang et al. 2020).

The material described by Dai et al. (2015) as H. sinensis irregularis is from the upper Xiazhen Formation (upper Katian) of Jiangxi, Southeast China. It is essentially identical to the holotype of Navoites irregularis , except in its smaller corallite size (0.73–0.81 mm in diameter), and we therefore treat them as conspecific. Han et al. (2017) identified H. sinensis irregularis from the lower Katian “Yingan Formation” of the Kalpin area, northwestern Xinjiang. Their material was poorly illustrated, and its attribution to N. irregularis needs confirmation.

The present revised diagnosis of N. irregularis is based on all the material now assigned to this species, and the major revision is an extension of the range of corallite size (0.73–1.15 mm). Its comparison with similar species is shown in Table 5 and discussed below. Navoites simmetricus Leleshus and Ospanova, 1979 , documented from the Upper Ordovician Archalyk Member of the Shakhriomon area, western Zeravshan Ridge, Tajikistan, differs from N. irregularis in having smaller corallite size (around 0.6 mm in diamter) and more complete tubular walls. The material described by Wang et al. (2020) as Navoites cargoensis Hill, 1957 ) from the upper Katian Malachis Hill Formation of New South Wales differs in having smaller corallite size 0.67–0.76 mm in diameter), less developed septal plates, and more complete tubular walls.

Two further species with 12 coenenchymal tubules are transferred herein to Navoites , also exhibiting similarities to N. irregularis . They include Stelliporella breviseptata Lin and Chow, 1977 , from the middle Sanqushan Formation (upper Katian) of Jiangxi, southeastern China, and Heliolites crassimuralis Lin and Huang, 1986 , from the lower Katian Beiguoshan Formation of Ningxia, northwestern China. Navoites breviseptata differs from N. irregularis in the development of smaller corallites (0.7–0.85 mm in diameter), denser tabulae and shorter septa, and Navoites crassimuralis is distinguished by having less developed septa, more concave tabulae, and more complete diaphragms.

Stratigraphic and geographic range.—The Yuanbaoshan Formation (lower Katian) of southern Kuruktag, northeastern Tarim, China; the middle Sanqushan Formation (upper Katian) of Jiangxi, Southeast China; the upper Xiazhen Formation (upper Katian) of Jiangxi, Southeast China; the “Yingan Formation” (lower Katian) of Kalpin, northwestern Tarim, China.