Kinnella cf. kielanae ( Temple, 1965 )
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publication ID |
https://doi.org/ 10.4202/app.2013.0010 |
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persistent identifier |
https://treatment.plazi.org/id/81298792-FFF1-A25A-FFDC-F9C7FDC7D0A6 |
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treatment provided by |
Felipe |
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scientific name |
Kinnella cf. kielanae ( Temple, 1965 ) |
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Kinnella cf. kielanae ( Temple, 1965)
Fig. 13A, C View Fig .
Material.— Two specimens. Porkuni Regional Stage , Kuldiga Formation , Hirnantian ( Upper Ordovician ); western Latvia. Drill core and depth (in meters) of brachiopod samples. Collection GIT 542 View Materials : Aispute-41, 1001.15; Riekstini-15 ,
858.6–?860.85.
Description. —Small biconvex shells up to 4.7 mm wide, ventral interarea high, catacline to slightly procline, weakly concave below the beak. Shell transversely oval with round- ed cardinal angles. Anterior commissure sulcate, may have a slight indention in the anterior part. Delthyrium is open, twice as high as wide. Dorsal valve is weakly convex in posterior part, anteriorly flattened; sulcus developed between the median primary costae; interarea is low, anacline with open notothyrium. Radial ornament is fascicostellate with medial costa on the ventral valve. Sixteen costae appear at umbo of the ventral valve, which increase in number by bifurcation up to 35 along the shell commissure; at 5 mm from umbo, 6 costae per 2 mm.
Remarks.—The position of the ventral interarea suggests that the Baltic specimens are most similar to those described from South China ( Rong 1979: pl. 1: 7, 1984: fig. 3). However, that feature is very variable ( Lespérance and Sheehan 1976; Stott and Jin 2007) and cannot be used as diagnostic. The Baltic specimens differ from the type species K. kielanae ( Temple 1965: 403) by less convex dorsal valve, more transverse outline and more robust ornament. The pre-Hirnantian Kinnella laurentiana Stott and Jin, 2007 from Canada (Manitoulin Island) differs from the Baltic specimens in having more convex valves, apsacline ventral area and arrangement of ribs with median costa on the dorsal valve instead of “a strong axial interspace in brachial valve…” on K. kielanae ( Temple 1965: 403) and the Baltic specimens.
In the East Baltic, Kinnella was probably present already in the upper Katian, in the Vormsi Stage ( Hints et al. 2007). Kinnella sp. ( Fig. 13D View Fig ) from that stage differs in the more variable size of costae and costellae and by an almost catacline ventral area.Another specimen ( Fig. 13B View Fig ) from the Pirgu Regional Stage in the Blidne-5 core probably belonging to Kinnella , differs from the others in the less transverse outline of the shell and by more robust ornament.
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