R.H. Schweers Thesis Plates and Plates Explanation

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Title

R.H. Schweers Thesis Plates and Plates Explanation

Subject

Nautiloidea, Fossil

Creator

?Schweers, Richard Henry

Date

circa 1933

Rights

CC BY-NC 3.0

Format

image/jpeg
text/pdf

Language

en

Type

StillImage
Text

Coverage

Missouri

Transcription

PLATE 1

Figs. 1-5 Thoracoceras newelli n. sp.
1. Dorso-lateral view of the holotype. Slightly over X 2.
Winterset limestone, Locality 2.
Holotype. Indiana University Paleontological Collection, no. 3539
2. Same specimen natural size.
3. Septal view of the same specimen. x 5.5.
4. Dorso-ventral polished section of the holotype showing the structure of the siphuncle (connecting rings restored). x12.
5. Thin-section of a specimen from the Farley limestone, De Soto, Kansas, showing the orthochoanitic structure of the siphuncle. x 8. After Newell.
Fig. 6. Thoracoceras sp.
View of a fragmentary and crushed specimen from Texas. x 5.5.
Figure specimen. Author's collection, no. 279.
Shale just below Ranger limestone (Canyon series), locality
Figs. 7-11. Knightoceras biforme n. sp.
7. Ventral view of an immature specimen, with much of the shell intact. x 1.

PLATE 1 CONTINUED

Winterset limestone, locality 2.
Holotype. Indiana University Paleontological Collection, no. 3589.
8. Lateral view of the same specimen showing the umbilical perforation and the apical portion of the conch with its distinctive ornamentation. x 1.
9-11. Ventral, lateral and apertural views respectively of a portion of the penultimate whorl of another specimen. x 1.
Winterset limestone, locality 2.
Paratype. Indiana University Paleontological Collection, no. 3590.

PLATE 2

Figs. 1-9. Knightoceras biforme n. sp.
1. Apertural view of the first volution of the holotype showing the distinctive ornamentation of the nepionic or apical portion of the shell, ventral sulcus and asymmetrical position of the siphuncle. x 2.3.
Winterset limestone, locality 2.
Holotype. Indiana University Paleontological Collection, no. 3589.
2. Lateral view of the same specimen showing the shape of the umbilical perforation, the cytoceran, gyroceran and tarphyceran elements of the first volution, and the nature of the shell ornamentation, with the lateral carina, revolving ridges and transverse annuli. The revolving ridges may be seen to extend for nearly the complete volution on the umbilical zones before becoming obsolete. Growth lines of the shell only are faintly represented on the adoral portion of the specimen. x 2.3.
3. Ventral view of the same specimen showing that the ventral sulcus and revolving ridges become obsolete at about one-half a volution, although the ridges nearer the lateral

PLATE 2 CONTINUED

angles are retained progressively longer. x 2.3.
4. View of the apical portion of the same specimen, commencing after the first camera and showing the outline of the whorl near the end of the first one-half volution. By the latter stage a dorsal furrow is well developed and the asymmetrical position of the siphuncle noticeably established. x 2.3.
5,6. Lateral and ventral views of the same apical portion particularly showing the nature of the ornamentation of the nepionic portion of the conch. x2.3.
7. Same as figure 6, more highly enlarged to show the shell ornamentation. x 4.5.
8. A dorso-central polished section of another specimen from the same locality showing the structure of the siphuncle. x 3.5.
Winterset limestone, locality 2.
Paratype. Indiana University Paleontological Collection, no. 3591.
9. Ventral view of the living chamber of probably a gerontic specimen from the same locality, showing the hyponomic sinus and growth lines of the shell. x 5/8.
Paratype. Indiana University Paleontological Collection, no. 3592.

PLATE 3

Figs. 1,2. Knightoceras biforme n.sp Lateral and apertural views of the internal mold of a complete probably mature specimen

Citation

?Schweers, Richard Henry, “R.H. Schweers Thesis Plates and Plates Explanation,” IU Paleontology Collection, accessed April 23, 2024, https://ngwennie.omeka.net/items/show/57.

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