UC Berkeley PaleoBios Title Checklist of California Paleogene–Neogene marine Mollusca since Keen and Bentson (1944) Permalink https://escholarship.org/uc/item/7t50309r Journal PaleoBios, 38(1) ISSN 0031-0298 Authors Groves, Lindsey T. Squires, Richard L. Publication Date 2021 DOI 10.5070/P9381052082 License https://creativecommons.org/licenses/by-nc-sa/4.0/ 4.0 Peer reviewed eScholarship.org Powered by the California Digital Library University of California PaleoBios 38:1–360, February 6, 2021 PaleoBios OFFICIAL PUBLICATION OF THE UNIVERSITY OF CALIFORNIA MUSEUM OF PALEONTOLOGY LINDSEY T. GROVES & RICHARD L. SQUIRES (2021). Checklist of California Paleogene–Neogene marine Mollusca since Keen and Bentson (1944). "Body fossils are obviously amongst the most powerful environmental indicators to be found in sedimen- tary rocks, and should be observed and identified with care." Andrew P. Miall (1984: p. 41) in Principles of sedimentary basin analysis, Springer-Verlag, New York. Cover: A representative of each class of Cenozoic California mollusks. A) bivalve Patinopecten healeyi (Arnold, 1906). B) gas- tropod Turritella infragranulata Gabb (1864). C) chiton Mopalia muscosa (Gould, 1846). D) scaphopod Dentalium neohex- agonum Sharp and Pilsbry in Pilsbry and Sharp (1897). E) nautiloid Aturia myrlae M.A. Hanna (1927). Scale bars=10 mm. Citation: Groves, L.T. and R.L. Squires. 2021. Checklist of California Paleogene–Neogene marine Mollusca since Keen and Bentson (1944). PaleoBios, 38. ucmp_paleobios_52082. Checklist of California Paleogene–Neogene marine Mollusca since Keen and Bentson (1944) LINDSEY T. GROVES1* and RICHARD L. SQUIRES2, 3 1Natural History Museum of Los Angeles County, Malacology Department, Los Angeles, CA 90007; [email protected] 2Professor Emeritus, California State University, Northridge, Department of Geological Sciences, CA 3Research Associate, Natural History Museum of Los Angeles County, Invertebrate Paleontology Department, Los Angeles, California, 90007; [email protected] This checklist is a sequel to the one published by A. Myra Keen and Herdis Bentson in 1944 and is an alphabet- ical listing of California marine Paleogene–Neogene mollusk species in the published literature spanning the interval of 1944 through 2020. The original data are given for each species and subspecies of bivalves, gastropods, chitons (polyplacophorans),or subspecies scaphopods, described and and/or cephalopods. figured Where detected, formation names, ages, taxonomy, systematics, and specimen disposition were corrected. A total of 559 genera and 1,698 species/subspecies were tabulated, with the bivalves and gastropods being the most abundant taxa. Bivalve and gastropod diversity steadily built up during the Paleocene, nearly doubled during the Eocene warm time, declined greatly during the cool time of the Oligocene, rebounded to its high- est peak in the Miocene and then declined slightly during the Pliocene. The other classes represented only minor faunal components. Chitons were only reported from the Pliocene, and cephalopods had their highest diversity during the Paleocene and Eocene. Bivalve genera having the highest diversity are: Glycymeris, Ma- coma, Mactromeris, Nuculana, and Tellina. Gastropod genera having the highest diversity are Cancellaria and Turritella. It is very likely that the Turritella overnamed. The high point of research productivity of published reports on California Paleogene-Neogene mollusks was in 1990–1994, and a species/subspecies complex has been significantly Menlo Park USGS Paleontology and Stratigraphy facility. An overall decline in productivity has continued, with noticeable upticks in 2003 and insignificant recent years. decline occurred in 1995–1996, following the closure of the Keywords: Bivalves, gastropods, chitons, scaphopods, cephalopods, taxonomy, biodiversity, fossil DEDICATION Springs, Colorado on May 23, 1905. She attended grad- This work is dedicated to Drs. Angeline Myra Keen uate school at Stanford University (M.S. degree in 1931) (1905–1986) (Fig. 1A) and Herdis Bentson (1914–2006) and then attended the University of California at Berke- (Fig. 1B), authors of ley (Ph.D. in 1934), with a dissertation in psychology. Tertiary Marine Mollusca.” Much has been written about Soon thereafter, she became interested in geology and Myra Keen and her lifethe summarized first “Check in list a memorialof California by paleontology Ellen Moore (USGS Menlo Park) (1988a). This memorial Department at Stanford, where she taught geology and contains a selected bibliography, as well as a selected paleontology courses.and became Eventually, affiliated she alsowith became the Geology inter- biography, about her. However, since very little has ested in malacology of the west coast of North America, been written about Herdis Bentson, her legacy has been and several of her graduate students at Stanford Univer- obscured. Thanks to her son Dr. Bentson H. McFarland sity became prominent malacologists and paleontologists (of Seattle, Washington) and to several online referenc- including Carole S. Hickman, James H. McLean, Judy T. es, we are able to provide her with some long overdue Smith, and Eugene V. Coan. She passed away at the age recognition. of 80 on January 4, 1986 in Santa Rosa, California. Myra Keen Herdis Bentson She was a world-renowned American malacologist Herdis Bentson was an American invertebrate pale- and molluscan paleontologist, who was born in Colorado ontologist, who later became interested in petroleum geology. She was born October 24, 1914 in Alameda, *author for correspondence California to Olaf R. and Agatha E. Bentson immigrants Citation: Groves, L.T. and R.L. Squires. 2021. Checklist of California Paleogene–Neogene marine Mollusca since Keen and Bentson (1944). PaleoBios, 38. ucmp_paleobios_52082. Permalink: https://escholarship.org/uc/item/7t50309r Copyright: Published under Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC-BY-NC-SA) license. 2 PALEOBIOS, VOLUME 38, FEBRUARY 2021 from the Eocene Capay shale of California,” a specimen they referred to as Eutrephoceras sp. (hypotype UCMP 11412). Herdis married William H. McFarland in 1948 and they had one child, son Bentson H. McFarland. In retirement, Bentson was active in conservation organi- zations in California, maintained contact with numerous relatives in Denmark as well as in the United States, and compiled a history focusing on her family’s migration to and their experiences in the Western Hemisphere. She passed away at the age of 92 on September 8, 2006. BIBLIOGRAPHY OF HERDIS BENTSON Bentson, H., 1940. A systematic study of the fossil gas- tropod Exilia. University of California Publications Bulletin of the Department of Geological Sciences 25(5):199–238, pls. 1–3. Bentson, H. 1943. Eocene (Capay) corals from Califor- nia. Journal of Paleontology 17(3):289–297, pls. 50–51. Keen, A.M. and H. Bentson. 1944. Check list of Cali- Figure 1. Images of Dr. Angeline Myra Keen (A, photo taken and provided by the late Dr. James H. McLean), and Dr. Herdis Bent- fornia Tertiary marine Mollusca. Geological Society of son (B, photo provided by Bentson McFarland). America Special Papers - 56: vii + 1–280, figs. 1–4. from Denmark. After attending public schools in Alam- lection types at the University of California. Journal of PaleontologyPeck, J.H. Jr. 28(3):297–309, and H.B. McFarland. pl. 29 .1954. Whitfield col family to do so, at the University of California, Berkeley whereeda, Herdis she completed entered college, her education as one of (B.A. the first1935, in M.A. her TAXA DESCRIBED BY HERDIS BENTSON paleontology 1937, Ph.D. paleontology 1941). She was elected an associate member of the American Museum of Gastropoda Exilia clarki of Paleontology at the University of California, Berkeley 8, 12, 15, 17, 19, 20. Type Locality: CASG 183, Cowlitz (UCMP),Natural History and was in the1936, second worked woman briefly to for earn the aMuseum PhD in Fm., Eocene, westBentson, bank Cowlitz 1940:215–216, River, Lewis pl. 2, Co., figs. Wash 2, 3,- paleontology from UCMP. Her doctoral thesis was on ington. Type Material: the stratigraphy and fauna of the Capay Eocene of Sac- ramento Valley, northern California. Holotype CAS 326 (pl. 2, figs. 2, Bentson started working in 1940 for the Standard Oil 20),3), paratype locality UCMPCAS 326-A 7161; [=CASG paratype 70883] UCMP (pl. 12141 2, fig. (pl. 12), 2, Company of California (now Chevron) then located in San locality CAS 183; paratype UCMP 12137 (pl. 2, figs. 19, Oiler” company magazine, which included a photograph Exilia llajasensis figs. 8, 15, 17), locality UCMPUCMP A3042,7161. Llajas Fm., Eocene, ofFrancisco. her giving She awas presentation featured in summarizingthe April 1945 her “Standard thesis. Type Locality: Simi Valley, Ventura Bentson,Co., California 1940:212, (as Lospl. 1, Angeles fig. 28, pl. Co., 2, She became an executive with Standard Oil, where she fig. 16. focused on petroleum exploration and retired in 1974, California in UCMP online database). Type Material: Holotype UCMP 12144 (pl. 2 UCMP and at Standard Oil, Herdis described four species UCMP 3296 [as Aliso Can- , fig. 16); paratype UCMP ofwith fossil the gastropodstitle of “lead-compilation” of the genus Exilia geologist. and six While species at yon (=Devil Canyon), Los Angeles Co., California UCMP 12140 (pl. 1, fig. 28), locality of fossil corals. Five species of fossils were named in her in online database]. honor: three gastropods; a scaphopod; and a radiolarian Exilia potreroensis