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Leptaena (Leptaena) ordovicica
Taxonomy
Leptaena ordovicica was named by Cooper (1956) [= Leptaena tenuistriata Sowerby var. Bassler, Cambrian and Ordovician: Maryland Geol. Surv., p. 260, pi. 49, fig. 2, 1919.
= Leptaena rhomboidalis (Wilckens) var. Reed 1917, p. 871 pars, non pl. xii, fig. 32. (see Williams 1962).]. Its type specimen is USNM 117669a and is a 3D body fossil. Its type locality is 0.6 mile northwest of Linville Station, which is in a Turinian marginal marine sandstone in the Oranda Formation of Virginia.
It was recombined as Leptaena (Leptaena) ordovicica by Candela and Harper (2014).
It was recombined as Leptaena (Leptaena) ordovicica by Candela and Harper (2014).
Sister species lacking formal opinion data
Synonymy list
| Year | Name and author |
|---|---|
| 1956 | Leptaena ordovicica Cooper pp. 820 - 821 figs. Plate 208, B, figures 19-21 ; plate 212, C, figure 32; plate 228, B, figures 8-18 |
| 1962 | Leptaena ordovicica Williams p. 198 figs. Pl. XIX, figs. 8, 9 |
| 1970 | Leptaena ordovicica Ross p. 66 figs. Plate 9, figure 6 |
| 2014 | Leptaena (Leptaena) ordovicica Candela and Harper pp. Supplement 1 |
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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.
†Leptaena (Leptaena) ordovicica Cooper 1956
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Diagnosis
| Reference | Diagnosis | |
|---|---|---|
| G. A. Cooper 1956 | Shell of about medium size for the genus, hinge forming the greatest width, the cardinal extremities angular and alate. Length equal to about three-fourths the width at the middle. Lateral margins excavate just anterior to the cardinal extremities, narrowly rounded at the anterolateral extremities and broadly rounded at the front margin. Surface unequally costellate, i to 2 of the smaller costellae alternating with the stronger ones. At the front margin 18 costellae occupy a space of 5 mm. Body with thin concentric undulations.
Pedicle valve with visceral region or body depressed below (brachiad) the rim marking place of geniculation ; umbonal region swollen, the swelling continued anteriorly as a low fold nearly to the rim of geniculation. Areas surrounding swollen fold and in front of it concave with gentle slopes from the umbo. Geniculated rim strong, located 12 mm. anterior to the beak, narrowly rounded in section, sharply bent at the anterolateral extremities of the body and extending with a broad curve convex outward to the anterior side of the ear. Angle of geniculation about 90°. Geniculated part nearly flat in profile, descending steeply to the anterior margin but less steeply around the sides to the ears. Interarea short, delthyriimi wide, partially covered by a short pseudodeltidium. Brachial valve closely fitting the pedicle valve ; umbo concave with concavity extended nearly to middle ; between concave area and point of geniculation valve is gently convex ; geniculated area marked by a deep groove. Interarea short. Interior of pedicle valve with subcircular to subflabellate muscle field ; diductor scars large, semiflabellate ; teeth strong, dental plates thick and flaring; pedicle callist small, apical. Entire visceral region tuberculate. Interior of brachial valve with short, low, median ridge, somewhat thickened adductor field and tuberculate surface. | |
| A. Williams 1962 | Thin-shelled, auriculate and subrectangular Leptaena with a disc, about 11 mm. long, defined by a sharp, dorsally directed geniculation; radial ornamentation consisting of differentially thickened costellae, about 6 per millimetre antero-medianly, disc with impersistently concentric rugae; sockets crenulated, median ridge of dorsal interior short, flanked laterally by two pairs of short divergent septa and anteriorly by a long median septum and a pair of lateral curved septa; ventral interior unknown. |