The oldest mysticete in the Northern Hemisphere.

Extant baleen whales (Mysticeti) uniquely use keratinous baleen for filter-feeding and lack dentition, but the fossil record clearly shows that "toothed" baleen whales first appeared in the Late Eocene.1 Globally, only two Eocene mysticetes have been found, and both are from the Southern Hemisphere: Mystacodon selenensis from Peru, 36.4 mega-annum (Ma) ago1,2 and Llanocetus denticrenatus from Antarctica, 34.2 Ma ago.3,4 Based on a partial skull from the lower part of the Lincoln Creek Formation in Washington State, USA, we describe the Northern Hemisphere's geochronologically earliest mysticete, Fucaia humilis sp. nov. Geology, biostratigraphy, and magnetostratigraphy places Fucaia humilis sp. nov. in the latest Eocene (ca. 34.5 Ma ago, near the Eocene/Oligocene transition at 33.9 Ma ago), approximately coeval with the oldest record of fossil kelps, also in the northeastern Pacific.5 This observation leads to our hypothesis that the origin and development of a relatively stable, nutrient-rich kelp ecosystem5,6 in the latest Eocene may have fostered the radiation of small-sized toothed mysticetes (Family Aetiocetidae) in the North Pacific basin, a stark contrast to the larger Llanocetidae (whether Mystacodon belongs to llanocetids or another independent clade remains unresolved) with the latest Eocene onset of the Antarctic Circumpolar Current in the Southern Hemisphere.7,8,9 Our discovery suggests that disparate mechanisms and ecological scenarios may have nurtured contrasting early mysticete evolutionary histories in the Northern and Southern hemispheres.

Early Oligocene kelp holdfasts and stepwise evolution of the kelp ecosystem in the North Pacific.

Kelp forests are highly productive and economically important ecosystems worldwide, especially in the North Pacific Ocean. However, current hypotheses for their evolutionary origins are reliant on a scant fossil record. Here, we report fossil hapteral kelp holdfasts from western Washington State, USA, indicating that kelp has existed in the northeastern Pacific Ocean since the earliest Oligocene. This is consistent with the proposed North Pacific origin of kelp associated with global cooling around the Eocene-Oligocene transition. These fossils also support the hypotheses that a hapteral holdfast, rather than a discoid holdfast, is the ancestral state in complex kelps and suggest that early kelps likely had a flexible rather than a stiff stipe. Early kelps were possibly grazed upon by mammals like desmostylians, but fossil evidence of the complex ecological interactions known from extant kelp forests is lacking. The fossil record further indicates that the present-day, multi-story kelp forest had developed at latest after the mid-Miocene climate optimum. In summary, the fossils signify a stepwise evolution of the kelp ecosystem in the North Pacific, likely enabled by changes in the ocean-climate system.

New species of latest Eocene/earliest Oligocene microgastropods (Heterobranchia: Orbitestellidae and Omalogyridae) from the Gries Ranch Formation, Lewis County, Washington State, USA.

Continued sampling of the latest Eocene to earliest Oligocene Gries Ranch Formation in Lewis County, Washington State, has yielded new heterobranch microgastropod species. Orbitestella kieli sp. nov., is the third fossil species of this genus and family Orbitestellidae from western North America. Two new species of Ammonicera, A. rolani sp. nov. and A. danieli sp. nov., are together only the second fossil record of this genus and the family Omalogyridae from the northeastern Pacific Ocean. New specimens of two previously recorded species, O. palaiopacifica Squires Goedert and A. benhami Squires Goedert, from early Eocene rocks of the Crescent Formation provide new data regarding shell morphology. The fossil record of both Ammonicera and Orbitestella in western North America is restricted to early Eocene to earliest Oligocene age rocks in Washington State.

Paleogene and Late Cretaceous Pteropoda (Mollusca, Gastropoda, Heterobranchia) from North America.

A comprehensive discussion and survey is made of all North American Paleogene and Late Cretaceous pteropods, and their systematics reviewed. From the West Coast of North America pteropod fossils have been collected from 23 localities in Washington State, and from the Gulf Coastal Plain they have been found in 40 localities. We also review earlier published specimens from boreholes in the Atlantic Coastal Plain. As a result, six new species are introduced from the Gulf Coast (Currylimacina asperita Garvie sp. nov., Heliconoides hodgkinsoni Garvie sp. nov., Limacina texanopsis Garvie sp. nov., Limacina parvabrazensis Garvie Janssen sp. nov., Limacina pseudopygmaea Garvie Janssen sp. nov., Cheilospicata cedrus Garvie sp. nov.) and one from Washington State (Clio gailae Goedert Janssen sp. nov.). The geographical distribution and/or stratigraphic ranges of several species has been extended, for example, Limacina canadaensis Hodgkinson, 1992, is reported for the first time from western North America. Some species originally described from elsewhere, Altaspiratella multispira (Curry, 1982), Heliconoides bartonensis (Curry, 1965), L. karasawai Ando, 2011, L. aff. valvatina (Reuss, 1867), Creseis spina (Reuss, 1867) and Clio chadumica Korobkov, 1966, are reported for the first time from the Americas. New specimens of several poorly known species yielded additional information on morphology or biostratigraphy. It is shown that some species have longer temporal ranges in America, occurring in, or continuing into younger deposits than those in Europe. In addition to the only Cretaceous pteropod from Washington State known so far, several enigmatic species possibly representing Pteropoda are described from the Late Cretaceous (Maastrichtian) and Danian of Texas, which allows a salient discussion on the early history of Pteropoda. An enigmatic specimen from the Eocene of Texas might represent a very early form of Gymnosomata. This analysis shows that there may be more pteropod species represented during the Late Cretaceous and Paleocene than previously suspected.

Scissurella nesbittae, new species, from the Gries Ranch Formation, Lewis County, Washington State (Gastropoda: Vetigastropoda: Scissurellidae).

Recent and fossil global scissurellids were monographed by Geiger (2012) and additional species were recently described from Brazil (Pimenta Geiger 2015). Here, we describe an additional fossil species from shallow water strata of the late Eocene Gries Ranch Formation in Lewis County, Washington State, USA.

Osedax borings in fossil marine bird bones.

The bone-eating marine annelid Osedax consumes mainly whale bones on the deep-sea floor, but recent colonization experiments with cow bones and molecular age estimates suggesting a possible Cretaceous origin of Osedax indicate that this worm might be able grow on a wider range of substrates. The suggested Cretaceous origin was thought to imply that Osedax could colonize marine reptile or fish bones, but there is currently no evidence that Osedax consumes bones other than those of mammals. We provide the first evidence that Osedax was, and most likely still is, able to consume non-mammalian bones, namely bird bones. Borings resembling those produced by living Osedax were found in bones of early Oligocene marine flightless diving birds (family Plotopteridae). The species that produced these boreholes had a branching filiform root that grew to a length of at least 3 mm, and lived in densities of up to 40 individuals per square centimeter. The inclusion of bird bones into the diet of Osedax has interesting implications for the recent suggestion of a Cretaceous origin of this worm because marine birds have existed continuously since the Cretaceous. Bird bones could have enabled this worm to survive times in the Earth's history when large marine vertebrates other than fish were rare, specifically after the disappearance of large marine reptiles at the end-Cretaceous mass extinction event and before the rise of whales in the Eocene.

Fossil traces of the bone-eating worm Osedax in early Oligocene whale bones.

Osedax is a recently discovered group of siboglinid annelids that consume bones on the seafloor and whose evolutionary origins have been linked with Cretaceous marine reptiles or to the post-Cretaceous rise of whales. Here we present whale bones from early Oligocene bathyal sediments exposed in Washington State, which show traces similar to those made by Osedax today. The geologic age of these trace fossils ( approximately 30 million years) coincides with the first major radiation of whales, consistent with the hypothesis of an evolutionary link between Osedax and its main food source, although older fossils should certainly be studied. Osedax has been destroying bones for most of the evolutionary history of whales and the possible significance of this "Osedax effect" in relation to the quality and quantity of their fossils is only now recognized.

Deep-sea food bonanzas: early Cenozoic whale-fall communities resemble wood-fall rather than seep communities.

The evolutionary history of invertebrate communities utilizing whale carcasses and sunken wood in the deep-sea is explored using fossil evidence. Compared to modern whale-fall communities, the Eo-Oligocene examples lack those vent-type taxa that most heavily rely on sulphide produced by anaerobic breakdown of bone lipids, but are very similar in their trophic structure to contemporaneous wood-falls. This sheds doubt on the hypothesis that whale-falls were evolutionary stepping stones for taxa that now inhabit hydrothermal vents and seeps. We suggest that the whale-fall communities reported here represent a new ecologic stage among whale-falls, which we have coined the 'chemosymbiotic opportunist stage' and that the 'sulphophilic stage' of modern whale-falls developed during the Early Miocene, resulting from a significant increase in both body size and/or oil content of bones among cetaceans during this time.