Species: Holtedahlina sulcata (de Verneuil, 1848)
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Formerly: Strophomena sulcata
Formerly: Strophomena sulcata
Map point data provided by iDigBio.
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- C5 Sequence (Lower Whitewater, Liberty, Waynesville)
Identification in Hand Sample
- Medium sized
- Gently biconvex
- Deep sulcus in the ventral valve with corresponding fold in the dorsal valve
- Coarser striations than any Strophomena in the Richmond
Holtedahlina sulcata from Whitewater Formation of Unknown County, (OUIP 1935)
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- Articulate brachiopod. Differs from similar forms by the deep sulcus in the pedicle valve. Waynesville to Elkhorn.
- Furcitella and Holtedahlina are most clearly separated by the presence of a promenent fold in adult valves of Holtedahlina. Heretofore, Furcitella has been distinguished principally by bifurcation of the medial ridge of the dorsal valve, but this character also occurs in immature specimens of H.sulcata (de Verneuil), type species of Holtedahlina. The bifid ends of the medial ridge of adult specimens of H.sulcata are enlarged to form rounded lobes (pl. 7, figs. 11-12). The dorsal trans-muscle ridges of H.suolcata (pl. 7, fig. 12) are more pronounced than those of Furcitella; the adsence of well-defined trans-muscle ridges in the specimen of H.sulcata illustrated by Cooper (1956, pl. 299, B, fig. 8; repeated by Williams, 1965, p. H386, fig. 247-1b) is anomalous.
Richards & Bambach (1975):
- One life assemblage of Holtedahlina sulcata is a nest of individuals several layers deep, with later generations apparently settling and growing on top of earlier ones (Richards, 1972). In this case, settling was continuous, or at least recurrent. In the case of Holtedahlina sulcata most of the specimens were still in their vertical life position in a shaley matrix with the beaks down and the closed shells filled with sparry calcite. Holtedahlina sulcata is the only strophomenid for which reliable population data could be obtained.
- Holtedahlina sulcata is unlike the other Richmondian strophomenids in morphology and ecology. It is a medium sized, gently biconvex, parvicostellate form with a broad sinus and fold. A pseudodeltidium leaves a small pedical opening at the beak. H. sulcata occurs as a common fossil in the Whitewater Formation, and is found in some abundance at restricted horizons in the Tanner’s Creek Formation. In-formation about the life habits of H. sulcata was derived from the study of a life assemblage found at Richmond, Indiana.
- Shell biconvex with fold on the brachial (dorsal) and sinus on the pedicle (ventral) valve, semi-circular, with hinge line about equal to greatest width of the shell. Muscular area of the pedical valve about three-tenths of the width of the valve, bounded posteriorly and laterally by a sharply elevated border which disappears anteriorly. Width, 18-23 mm, length 0.8 width. Striae about three in 2 mm.
- S. sulcata has a vertical range from the Clarksville Member (of Waynesville Formation) to the top of the Whitewater Formation. In the Liberty-Whitewater it is represented in Kentucky as far south as Madison and Marion counties. In the Waynesville it is known from the Clarksville in Lewis County.
- Shell small; coarser striations than any other Strophomena in the Richmond. Median part of the pedicle (ventral) valve depressed into a broad sinus anteriorly, corresponding part of brachial (dorsal) valve raised into a low, median fold.
- Locality and Horizon: Richmond formation from Clarksville division of the Waynesville to the top of the Whitewater in Kentucky. Its southernmost range known is Dismukes, Sumner County, Tennessee, in the Waynesville. At Stonington, Michigan, in the Waynesville; in Canada, but only in the Meaford, on Manitoulin island, at Kagawong, and at several localities south of Little Current. In the lower, Lorraine-like phase of the Waynesville at Streetsville. Related forms occur at Vars, and on Snake island.