Glycymeris andersoni, DICKERSON, 1917

Hickman, Carole S., 2023, Paleogene marine bivalves of the deep-water Keasey Formation in Oregon, Part II: The pteriomorphs, PaleoBios 40 (5), pp. 1-51 : 15

publication ID

https://doi.org/ 10.5070/P940561331

publication LSID

lsid:zoobank.org:pub:1756B24A-813B-423F-896F-91B21FF58A79

DOI

https://doi.org/10.5281/zenodo.11505103

persistent identifier

https://treatment.plazi.org/id/C23987DD-FFE8-292D-FC04-FD07EFE5B858

treatment provided by

Felipe

scientific name

Glycymeris andersoni
status

 

GLYCYMERIS ANDERSONI DICKERSON, 1917

FIGS. 8A–E View Figure 8 , 9A, B View Figure 9

Glycymeris andersoni Dickerson (1917) . pp. 166–167; pl. 27, figs. 3a–c.

Glycymeris andersoni Dickerson, Effinger (1938) . p. 366.

Glycymeris andersoni Dickerson, Weaver (1943) . p. 59; pl. 10, figs. 5, 11.

Discussion — Glycymeris andersoni is easily recognized by its ovate, moderately inflated, nearly equilateral shell with broad flat-topped radial ribs and narrow interspaces accentuated by chalky preservation ( Fig. 8B, D View Figure 8 ). The commissural margin is strongly crenulate ( Fig. 8D View Figure 8 ) and the interlocking of the valves is further reinforced by interior crenulation ( Fig. 8A, C View Figure 8 ). Maximum shell size is large (length and height> 25 mm) relative to species in the older tropical Eocene faunas of the Pacific Northwest and California. It is abundant in the Gries Ranch Formation and represented by both juvenile and adult specimens of equal linear dimension, consistent with isometric growth. The dorsal slope angle does not differ between large and small shells ( Fig. 9A, B View Figure 9 ), indicating isometric growth.

A second Gries Ranch glycymeridid species, described subsequently by Effinger (1938), is treated below, and figured for comparison.

Material examined — 39 specimens from Loc. UCMP IP2289 View Materials .

Type information —Figured hypotypes, all from Loc. UCMP IP2289 View Materials : UCMP 110729 View Materials , length 19.5 mm, height 19.2 mm; UCMP 110730 View Materials , length 22.1 mm, height 21.6 mm; UCMP 110731 View Materials , length 29.0 mm, height 27.7 mm; UCMP 110732 View Materials , length 19.0 mm, height 17.1 mm; UCMP 110733 View Materials , length 8.2 mm, height 7.6 mm.

Stratigraphic occurrence —This species is known only from the Gries Ranch Formation. It is not present in the tropical Eocene fauna of the underlying Cowlitz Formation or in the recovery fauna of the overlying Pittsburg Bluff and Eugene Formations.

UCMP

University of California Museum of Paleontology

Kingdom

Animalia

Phylum

Mollusca

Class

Bivalvia

SubClass

Pteriomorphia

Order

Arcida

Family

Glycymerididae

Genus

Glycymeris

Loc

Glycymeris andersoni

Hickman, Carole S. 2023
2023
Loc

Glycymeris andersoni

Dickerson, Weaver 1943
1943
Loc

Glycymeris andersoni

Dickerson, Weaver 1943
1943
Loc

Glycymeris andersoni

Dickerson, Effinger 1938
1938
Loc

Glycymeris andersoni Dickerson (1917)

DICKERSON 1917
1917
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