Dictyoclostus Muir-Wood, 1930
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publication ID |
https://doi.org/ 10.4202/app.00972.2022 |
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persistent identifier |
https://treatment.plazi.org/id/41708783-FFCE-FFA3-8C7E-CE42FB1DFB7F |
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treatment provided by |
Felipe |
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scientific name |
Dictyoclostus Muir-Wood, 1930 |
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Genus Dictyoclostus Muir-Wood, 1930 View in CoL
Type species: Conchyliolithus Anomites ( semireticulatus ) Martin, 1809, from the Visean of Great Britain and Ireland.
Remarks.— Dictyoclostus differs from Pugilis in its less elongated shell outline, stronger reticulation on the visceral disc and ribbing on the trail, and different ventral spine arrangement.
Dictyoclostus pinguis ( Muir-Wood, 1928) Fig. 11G–H View Fig .
1928 Productus pinguis ; Muir-Wood 1928: 104, pl. 5: 1, 2a–d, 3; pl. 6: 1; text-fig. 20.
1952 Dictyoclostus pinguis ( Muir-Wood, 1928) ; Sarycheva and Sokolskaya 1952: 142, pl. 38: 191.
1991 Dictyoclostus pinguis ( Muir-Wood, 1928) ; Brunton and Tilsley 1991: 291.
2000 Dictyoclostus pinguis ( Muir-Wood, 1928) ; Brunton et al. 2000: fig. 331: e.
2016 Dictyoclostus pinguis ( Muir-Wood, 1928) ; Tazawa et al. 2016: 53, fig. 5.3. (cum syn.)
Material.—One ventral valve: MPUM 11950 ( RCC 54-11). Two dorsal valves: MPUM 11951 ( RCK 15-63a); MPUM 11952 RCC 2-23a). Two fragments: MPUM 11953 ( RCC 1-10; RCC 1B-23). All from mud mound complex of Ricklow Quarry, Monyash, Derbyshire, UK, Monsal Dale Limestone Formation, Brigantian, upper Visean.
Description.—Large-sized, concavo-convex shell with transversely subrectangular outline; cardinal margin wide, almost corresponding to the maximum width. Anterior commissure rectimarginate. Ventral geniculation angle 90°. Visceral disc flattened medianly. Trail long, convex. Dorsal visceral disc flat posteriorly, gently concave anteriorly. Geniculation angle 70°. Low rounded fold starting at disc mid-length, becoming obsolete on trail.
Ornamentation consists of low, rounded ribs with narrow interspaces posteriorly, wide anteriorly. Ribs increase in number anteriorly by bifurcation on the ventral valve, by intercalation on the dorsal one. Ribs number 10–12 per 10.0 mm, 25.0 mm from the umbo. Ventral and dorsal visceral discs bearing low, rounded rugae, densely packed posteriorly (four per 5.0 mm length), lower and wider anteriorly (5–6 per 5.0 mm length). Intersection between ribs and rugae results in reticulate ornamentation.
Long and robust dorsal median septum, 1.0 mm wide, extending at least to one-third of visceral disc length.
Remarks.—The specimens are similar to the specimens of Dictyoclostus pinguis figured by Muir-Wood (1928) and Brunton et al. (2000). They differ from D. semireticulatus ( Martin, 1809) in having a geniculated dorsal valve and finer ribbing.
Stratigraphic and geographic range.— Dictyoclostus pinguis is recorded in the Brigantian, uppermost Visean, of England and Scotland (e.g., Muir-Wood 1928; Mitchell 1971; this study), in the lower Visean of Tianshan–northern Junggar, north-western China (e.g., Shen et al. 2017) and the Serpukhovian of the Moscow Basin ( Sarycheva and Sokolskaya 1952).
Genus Pugilis Sarycheva, 1949
Type species: Producta pugilis Phillips, 1836 , from the Brigantian , uppermost Visean, of Yorkshire, England .
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.
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Dictyoclostus Muir-Wood, 1930
| Carniti, Alessandro P., Porta, Giovanna Della, Banks, Vanessa J., Stephenson, Michael H. & Angiolini, Lucia 2022 |
Dictyoclostus pinguis ( Muir-Wood, 1928 )
| Tazawa, J. & Ibaraki, Y. & Nishikawa, I. 2016: 53 |
Dictyoclostus pinguis ( Muir-Wood, 1928 )
| Brunton, C. H. C. & Tilsley J. W. 1991: 291 |
Dictyoclostus pinguis ( Muir-Wood, 1928 )
| Sarycheva, T. G. & Sokolskaya, A. N. 1952: 142 |
Productus pinguis
| Muir-Wood, H. M. 1928: 104 |