Tylothyris laminosa ( M’Coy, 1841 )

Sun, Yuanlin & Baliński, Andrzej, 2011, Silicified Mississippian brachiopods from Muhua, southern China: Rhynchonellides, athyridides, spiriferides, spiriferinides, and terebratulides, Acta Palaeontologica Polonica 56 (4), pp. 793-842 : 833

Tylothyris laminosa ( M’Coy, 1841)

Figs. 7C , 31 .

1841 Spirifera laminosa M’Coy ; M’Coy 1841: 26. 1844 Cyrtia laminosa (M’Coy) ; M’Coy 1844: 137, pl. 21: 4. 1969 Tylothyris laminosus (Mc’Coy); Litvinovich et al. 1969: 280, pl.

69: 4, 5. 1979 Tylothyris laminosa ( M’Coy, 1844) ; Nalivkin 1979: 131, pl. 49:

15. 1984 Tylothyris laminosa (M’Coy) ; Brunton 1984: 77–83, figs. 108–119. 2006 Tylothyris laminosa laminosa ( M’Coy, 1841) ; Bassett and Bryant

2006: 518–520, pl. 12: 1–8, pl. 14: 1–18, pl. 15: 1–19, pl. 16: 1–6. 2006 Tylothyris laminosa (M’Coy) ; Liao and Zhang 2006: pl. 5: 1–6. 2010 Tylothyris laminosa ( M’Coy, 1841) ; Mottequin 2010: 270–271,

pl. 6: 4–26; fig. 13.

Material.—About 90 single valves, most of them well preserved. All specimens from sample MH1 apart a few fragments found in sample Mu−42

Description.—This species has been described in great detail and abundantly illustrated by North (1920), Brunton (1984), and Bassett and Bryant (2006).

Remarks.—This is one of the most characteristic spiriferoid brachiopods in the Muhua fauna. Its shell shape, ornamentation and details of the internal structures are very similar to Tylothyris laminosa from the Tournaisian and Viséan of the British Isles (see Brunton 1984; Bassett and Bryant 2006). The only difference observed between the specimens from Europe and China is the occasionally developed weak costation on the dorsal fold of the valves here studied.

The specimens from Muhua have greater number of costae than Tylothyris clarksvillensis (Winchell, 1865) described by Rodriguez and Gutschick (1967) from the early Mississippian of Western Montana, and Tylothyris missouriensis ( Weller, 1914) from the early Mississippian of Illinois (see Carter 1988). The specimens described here are much less transversally expanded than Tylothyris transversa Roberts, 1971 described from the Tournaisian of Northwestern Australia (see Roberts 1971).

Stratigraphic and geographic range.—The species is known from the late Tournaisian and Viséan of western Europe, the Middle East, the Urals, Kazakhstan, Australia, Japan, and China (see Litvinovich et al. 1969; Nalivkin 1979; Brunton 1984; Tazawa et al. 1984; Liao and Zhang 2006; Mottequin 2010; and herein). Related forms were described as Tylothyris sp. aff. laminosa from the Tournaisian of Morocco ( Brice et al. 2005) and as Tylothyris (?) cf. laminosa from the lower Carboniferous of Rudny Altai, Russia ( Bublichenko 1976).

Figures

Fig. 7. Shell encrustation in silicified brachiopods from the Tornaisian Muhua Formation, southern China. A. Chonetoid shell encrsuted by strophalosiidine Muhuarina haeretica Baliński and Sun, 2005, PKUM02−0080, (new photograph of specimens illustrated by Baliński and Sun 2008: fig. 1E and Sun and Baliński 2008: fig. 18C). B. Interior of dorsal valve of spiriferinide Spiriferellina cf. insculpta Phillips, 1836, PKUM02−0388, in general (B1) and enlarged (B2) views showing infestation by endobiont Haplorygma dorsalis Baliński and Sun, 2010b (see also Baliński and Sun 2010b: fig. 1A; new photographs). C. SEM micrographs of dorsal valve of spiriferide Tylothyris laminosa (M’Coy, 1841), PKUM02−0389, showing infestation by H. dorsalis in general (C1) and enlarged (C2) views (see also Baliński and Sun 2010b: fig. 1B; new photographs). Samples GB (A, B) and MH1 (C).

Fig. 31. Delthyridoid brachiopod Tylothyris laminosa (M’Coy, 1841) from the Tornaisian Muhua Formation, southern China. A, B. Exterior of ventral (A) and dorsal (B) valves, PKUM02−0557 (A) and PKUM02−0558 (B). C. Ventral valve, PKUM02−0559, in exterior (C1), interior (C2), and lateral (C3) views. D. Detail of external shell micro−ornamentation, PKUM02−0560. E, F. Interior of two dorsal valves, PKUM02−0561 (E) and PKUM02−0562 (F), in general (E1, F1) and enlarged (E2, F2) views. G. Dorsal valve, PKUM02−0563, in exterior (G1) and interior (G2) views. H. Exterior of dorsal valve, PKUM02−0564. I. Slightly damaged ventral valve, PKUM02−0565, in anterior (I1) and enlarged (I2) views; SEM micrographs. J. Juvenile ventral valve, PKUM02−0566, in exterior (J1) and interior (J2) views. K. Exterior of juvenile ventral valve, PKUM02−0567. L. Incomplete dorsal valve, PKUM02−0568, with well preserved lamellose ornamentation, in general (L1) and detailed (L2) views. All from sample MH1.