Promyalina schamarae (Bittner 1899)
- Dataset
- A silicified Early Triassic marine assemblage from Svalbard
- Rank
- SPECIES
Classification
- kingdom
- Animalia
- phylum
- Mollusca
- class
- Bivalvia
- order
- Myalinida
- family
- Myalinidae
- genus
- Promyalina
- species
- Promyalina schamarae
description
(Fig. 2 C – G) 1899 Myalina schamarae Bittner 19, pl. 4, figs 20 – 25. 2009 Promyalina schamarae (Bittner); Kumagae & Nakazawa: 157, fig. 144, 4 – 5.
description
Description. Shell is small, mytiliform, inequilateral, prosocline, higher than long, and moderately inflated. Umbo is small, terminal and prosogyrate. Posterior dorsal margin is straight. Posterior margin is slightly convex, forming a rounded posteroventral margin. Anterior margin is long, nearly straight or weakly acute and partly depressed near the umbo.
discussion
Remarks. The internal characters of the shells cannot be observed because all the specimens are articulated. Externally, the shells resemble Promyalina schamarae from the Griesbachian Lazurnaya Bay Formation, Russia (Shigeta et al. 2009), and are therefore assigned to this species. These specimens differ from P. groenlandica (Newell, 1955), as the beak does not project beyond the dorsal margin, and from P. spathi in having a more convex anterior margin. Mode of life. Surficial, stationary, attached, suspension feeder (Stanley 1972).
materials_examined
Material. Three specimens from LD- 04 (NHMUK PE PEI 5484; NHMUK PI MB 1202; NHMUK PI MB 1205) and seven specimens from LD- 05 (NHMUK PI MB 1188; NHMUK PI MB 1203 – 1204; NHMUK PE PEI 5475 – 5476; NHMUK PE PEI 5500; NHMUK PE PEI 5503).
Name
- Homonyms
- Promyalina schamarae (Bittner 1899)