Orbitestella palaiopacifica Squires & Goedert, 1996

Chernyshev, Alexei V. & Goedert, James L., 2021, New species of latest Eocene / earliest Oligocene microgastropods (Heterobranchia Orbitestellidae and Omalogyridae) from the Gries Ranch Formation, Lewis County, Washington State, USA, Zootaxa 4981 (3), pp. 469-480 : 471

publication ID

https://doi.org/ 10.11646/zootaxa.4981.3.3

publication LSID

lsid:zoobank.org:pub:CB36C384-5538-494A-8802-4F821C7E25FE

DOI

https://doi.org/10.5281/zenodo.5109761

persistent identifier

https://treatment.plazi.org/id/038287AE-C140-1749-FF7F-5E7F0B69082C

treatment provided by

Plazi

scientific name

Orbitestella palaiopacifica Squires & Goedert, 1996
status

 

Orbitestella palaiopacifica Squires & Goedert, 1996 View in CoL

Figure 1A–C View FIGURE 1

Orbitestella palaiopacifica Squires & Goedert, 1996, p. 233 View in CoL , figs. 22–26.

Examined material. MIMB 41133 View Materials (lot of 6 specimens) , SBMNH 467055 About SBMNH (lot of 2 specimens), from the type locality .

Type material. Holotype: LACMIP 11365 ; Paratypes, LACMIP 11366–11367 .

Type locality. LACMIP loc. 16655, Larch Mountain , Black Hills , Washington State, USA; Crescent Formation, middle early Eocene .

Diagnosis. “An Orbitestella with an upper whorl surface crossed by narrow axial ribs, a keel-like carina on the shoulder, axial ribs in the interspace between the carina on the basal margin and the carina on the edge of the umbilicus, and a wide but deep umbilicus showing overlapping whorls in its interior.” (Squires & Goedert 1996).

Remarks. Shells of O. palaiopacifica were reported to be up to 0.3 mm high with a diameter of 0.53 mm by Squires & Goedert (1996); a new specimen (MIMB 41133–2; Fig. 1B View FIGURE 1 ) is now the largest known specimen with a diameter of 0.9 mm. New specimens of O. palaiopacifica show that the axial ribs cross the prominent keel-like carina on the shoulder, and spiral threads are present on most surfaces, including the apical and basal carinae. Squires & Goedert (1996) stated that the protoconch of O. palaiopacifica was apparently smooth, but we think this is due to poor preservation of the protoconch. The protoconch surface of the newly available specimens appears also to be corroded. Orbitestella palaiopacifica is still known only from two localities of the Crescent Formation in the Black Hills southwest of Olympia, Washington.

Kingdom

Animalia

Phylum

Mollusca

Class

Gastropoda

Order

Heterostropha

Family

Orbitestellidae

Genus

Orbitestella

Loc

Orbitestella palaiopacifica Squires & Goedert, 1996

Chernyshev, Alexei V. & Goedert, James L. 2021
2021
Loc

Orbitestella palaiopacifica

Squires & Goedert 1996: 233
1996
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