Litosphaeridiumtoo: Two new dinoflagellate cyst species from the cretaceous of California

Abstract

Occasionally (and fortunately), circumstances and timing combine to allow an individual, almost singlehandedly, to generate a paradigm shift in his or her chosen field of inquiry. William R. ('Bill') Evitt (1923À2009) was such a person. During his career as a palaeontologist, Bill Evitt made lasting and profound contributions to the study of both dinoflagellates and trilobites. He had a distinguished, long and varied career, researching first trilobites and techniques in palaeontology before moving on to marine palynomorphs. Bill is undoubtedly best known for his work on dinoflagellates, especially their resting cysts. He worked at three major US universities and spent a highly significant period in the oil industry. Bill's early profound interest in the natural sciences was actively encouraged both by his parents and at school. His alma mater was Johns Hopkins University where, commencing in 1940, he studied chemistry and geology as an undergraduate. He quickly developed a strong vocation in the earth sciences, and became fascinated by the fossiliferous Lower Palaeozoic strata of the northwestern United States. Bill commenced a PhD project on silicified Middle Ordovician trilobites from Virginia in 1943. His doctoral research was interrupted by military service during World War II; Bill served as an aerial photograph interpreter in China in 1944 and 1945, and received the Bronze Star for his excellent work. Upon demobilisation from the US Army Air Force, he resumed work on his PhD and was given significant teaching duties at Johns Hopkins, which he thoroughly enjoyed. He accepted his first professional position, as an instructor in sedimentary geology, at the University of Rochester in late 1948. Here Bill supervised his first two graduate students, and shared a great cameraderie with a highly motivated student body which largely comprised World War II veterans. At Rochester, Bill continued his trilobite research, and was the editor of the Journal of Paleontology between 1953 and. Seeking a new challenge, he joined the Carter Oil Company in Tulsa, Oklahoma, during 1956. This brought about an irrevocable realignment of his research interests from trilobites to marine palynology. He undertook basic research on aquatic palynomorphs in a very well-resourced laboratory under the direction of one of his most influential mentors, William S. 'Bill' Hoffmeister. Bill Evitt visited the influential European palynologists Georges Deflandre and Alfred Eisenack during late 1959 and, while in Tulsa, first developed several groundbreaking hypotheses. He soon realised that the distinctive morphology of certain fossil dinoflagellates, notably the archaeopyle, meant that they represent the resting cyst stage of the life cycle. The archaeopyle clearly allows the excystment of the cell contents, and comprises one or more plate areas. Bill also concluded that spine-bearing palynomorphs, then called hystrichospheres, could be divided into two groups. The largely Palaeozoic spine-bearing palynomorphs are of uncertain biological affin...

Detrital zircon U–Pb reconnaissance of the Franciscan subduction complex in northwestern California

“…ages is generally quite incomplete (e.g. Evitt and Pierce 1975;Blake et al 1988;Murchey and Blake 1993;McLaughlin et al 1994McLaughlin et al , 2000Lucas-Clark 2007). The oceanic basalts in the Franciscan cannot be dated using current isotopic methods.…”

“…Focusing near our study area, roughly 12 samples from probable mélange matrix have yielded microfossils with essentially Cretaceous ages (145-65 Ma), with a possible clustering in the Albian (112-98 Ma; Gucwa 1974Gucwa , 1975O'Day 1974;Lucas-Clark 1986, 2007Larue 1986;McLaughlin et al 2000). However, essentially all megafossils in the mélange are Tithonian to Valanginian (151-137 Ma;Suppe 1969Suppe , 1973Irwin et al 1974;Blake and Jones 1974;Lehman 1974;Jordan 1978).…”

“…Fossil localities farther south in the San Francisco Bay region are not included. Fossil sources: Alvarez et al (1980);Berkland (1972Berkland ( , 1973Berkland ( , 1978; Blake and Jones (1974); Clark (1940); Evitt and Pierce (1975); Gucwa (1974Gucwa ( , 1975; Hagstrum and Murchey (1993); Irwin et al (1974); Jayko (1984); Jayko et al (1989); Jordan (1978); Kaplan (1983Kaplan ( , 1984; Koski et al (1993); Larue (1986); Lehman (1974); Lucas-Clark (1986, 2007; Mankinen et al (1991); McLaughlin and Pessagno (1978); McLaughlin and Ohlin (1984); McLaughlin et al (2000); O'Day (1974); Murchey and Blake (1993); Ohlin et al (2010); Orchard (1979); Sliter (1984); Suppe (1969Suppe ( , 1973; Tarduno et al (1986Tarduno et al ( , 1990. Note that the extensive fossil compilation table in Jayko et al (1989) contains numerous errors, which we have corrected from original sources as shown in Table DR7.…”

“…Experience has shown that, by focusing on favourable lithologies such as carbonate concretions, limestone blocks, and radiolarian cherts, roughly 50% of samples may be useful (e.g. Evitt and Pierce 1975;Murchey and Jones 1984;Sliter 1984;Lucas-Clark 1986, 2007McLaughlin et al 2000). Nevertheless, the number of published microfossil localities in the area of Figure 2 is only about 50, and many samples (especially mudstones) yield only imprecise age calls (e.g.…”

“…It also appears that genuine potential exists for future dinoflagellate work. In two areas, Lucas-Clark (1986, 2007 was able to determine late Albian ages within a tight 4-million-year range, using samples from lenses of carbonate nodules and limestone, where preservation is generally better. Larue (1986) reported relatively imprecise age calls (e.g.…”