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Rhipidomena

Strophomenata - Strophomenida - Rafinesquinidae

Taxonomy
Rhipidomena was named by Cooper (1956) [Sepkoski's age data: O Llde O Cara-l Sepkoski's reference number: 1,397]. It is not extant. Its type is Strophomena tennesseensis.

It was assigned to Strophomenidae by Cooper (1956); to Rafinesquininae by Williams et al. (2000); and to Strophomenida by Sepkoski (2002).

Synonymy list
YearName and author
1956Rhipidomena Cooper pp. 866 - 867
2000Rhipidomena Williams et al. p. 241
2002Rhipidomena Sepkoski, Jr.

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RankNameAuthor
kingdomAnimalia()
Triploblastica
Eutriploblastica
Neotriploblastica
Eucoelomata
superphylumLophotrochozoa
Lophophorata
phylumBrachiopodaCuvier 1805
RankNameAuthor
subphylumRhynchonelliformeaWilliams et al. 1996
classStrophomenataWilliams et al 1996
orderStrophomenidaOpik 1934
superfamilyStrophomenoideaKing 1846
familyRafinesquinidaeSchuchert 1893
subfamilyRafinesquininaeSchuchert 1893
genusRhipidomena

If no rank is listed, the taxon is considered an unranked clade in modern classifications. Ranks may be repeated or presented in the wrong order because authors working on different parts of the classification may disagree about how to rank taxa.

Diagnosis
ReferenceDiagnosis
G. A. Cooper 1956Shells generally large, attaining a length of about 2 inches and a width of nearly 2.5 inches ; generally wider than long, usually somewhat parallel sided cardinal extremities subrectangular to subauriculate ; convexi-concave in the adult but concavo-convex when young; anterior commissure rectimarginate. Surface finely costellate, strong and fine costellae alternate and appear in several generations; entire surface covered by fine concentric fila. Pseudopunctae finely and densely matted.

Pedicle valve with minute pedicle foramen, pseudodeltidium of moderate size and convexity; teeth small, surface smooth or roughened, supported by callus thickening ; muscle area large, occupying about half the valve area ; diductor scars broad and flabellate ; adductor scars small, located at about the middle of the muscle field on 2 low, subparallel ridges that extend anteriorly to about the valve middle where the diductors end. Posterior of delthyrial cavity filled by adventitious shell. Anterior and lateral margins with thickened inner rim.

Brachial interior with thickened notothyrial platform bearing 2 stout lobes of the cardinal process having short shafts and flat myophore surfaces. Brachiophores visible as short, flat blades on the inner side of the sockets and nearly buried by adventitious shell material. Median ridge short and low ; adductor field marked by 4 short radiating ridges, 2 on each side of the median ridge ; moderately thickened rim just inside margins, but not so prominent as that of the pedicle valve.