Thyasirid bivalves from Cretaceous and Paleogene cold seeps KRZYSZTOF HRYNIEWICZ, KAZUTAKA AMANO, ROBERT G. JENKINS, and STEFFEN KIEL Hryniewicz, K., Amano, K., Jenkins, R.G., and Kiel, S. 2017. Thyasirid bivalves from Cretaceous and Paleogene cold seeps. Acta Palaeontologica Polonica 62 (4): 705–728. We present a systematic study of thyasirid bivalves from Cretaceous to Oligocene seep carbonates worldwide. Eleven species of thyasirid bivalves are identified belonging to three genera: Conchocele, Maorithyas, and Thyasira. Two spe- cies are new: Maorithyas humptulipsensis sp. nov. from middle Eocene seep carbonates in the Humptulips Formation, Washington State, USA, and Conchocele kiritachiensis sp. nov. from the late Eocene seep deposit at Kiritachi, Hokkaido, Japan. Two new combinations are provided: Conchocele townsendi (White, 1890) from Maastrichtian strata of the James Ross Basin, Antarctica, and Maorithyas folgeri (Wagner and Schilling, 1923) from Oligocene rocks from California, USA. Three species are left in open nomenclature. We show that thyasirids have Mesozoic origins and appear at seeps be- fore appearing in “normal” marine environments. These data are interpreted as a record of seep origination of thyasirids, and their subsequent dispersal to non-seep environments. We discuss the age of origination of thyasirids in the context of the origin of the modern deep sea fauna and conclude that thyasirids could have deep sea origins. This hypothesis is supported by the observed lack of influence of the Cretaceous and Paleogene Oceanic Anoxic Events on the main evolutionary lineages of the thyasirids, as seen in several other members of the deep sea fauna. Key words: Bivalvia, Thyasiridae, cold seeps, deep sea, ecology, evolution, Cretaceous, Paleogene. Krzysztof Hryniewicz [[email protected]], Institute of Paleobiology, Polish Academy of Sciences, ul. Twarda 51/55, 00-818 Warszawa, Poland. Kazutaka Amano [[email protected]], Department of Geoscience, Joetsu University of Education, 1Yamayashiki Joetsu City, Niigata 943-8512, Japan. Robert G. Jenkins [[email protected]], School of Natural System, College of Science and Engineering, Kanazawa University, Kanazawa City, Ishikawa 920-1192, Japan. Steffen Kiel [[email protected]], Swedish Museum of Natural History, Department of Palaeobiology, Box 500 07, 104 05 Stockholm, Sweden. Received 23 may 2017, accepted 2 August 2017, available online 31 October 2017. Copyright © 2017 K. Hryniewicz et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License (for details please see http://creativecommons.org/licenses/by/4.0/), which permits unre- stricted use, distribution, and reproduction in any medium, provided the original author and source are credited. lucinid and thyasirid bivalves, have received less attention, Introduction although often being dominant in some Recent cold seeps Marine chemosynthesis-based ecosystems comprise hydro- (Kharlamenko et al. 2016). Fossil lucinid bivalves are rela- thermal vents (e.g., Van Dover 2000), hydrocarbon seeps tively well known, commonly comprising the main faunal (e.g., Sibuet and Olu 1998; Levin 2005) and wood and nek- element of Cretaceous and Paleogene seeps (Kiel 2013). ton falls (Smith and Baco 2003; Bernardino et al. 2010). The focus of this study are the less well known fos- Hydrocarbon seeps are submarine edifices where low-tem- sil thyasirid seep faunas. Many species are known from perature fluids are released to the water column (Judd Cretaceous to Pleistocene seep deposits worldwide (e.g., and Hovland 2007). These environments are populated by Van Winkle 1919; Yabe and Nomura 1925; Kauffman 1967; faunas dominated by macroinvertebrate species living in Squires and Gring 1996; Goedert et al. 2003; Kiel et al. symbiosis with chemoautotrophic bacteria (Levin 2005), 2008; Amano et al. 2013). Although thyasirids are rarely among which the most iconic are epifaunal and semi-in- common in ancient seep settings, the genus Cretaxinus faunal groups like vestimentiferan tubeworms (Bright and Hryniewicz, Little, and Nakrem, 2014, was reported to be Lallier 2010), vesicomyid clams and bathymodiolin mussels restricted to ancient seep environments, and it is possible (Taylor and Glover 2010) and large abyssochrysoid gas- that one more thyasirid genus occurs at fossil seeps only tropods (Sasaki et al. 2010). Infaunal groups, among them (Nobuhara et al. 2008). Despite a growing volume of data Acta Palaeontol. Pol. 62 (4): 705–728, 2017 https://doi.org/10.4202/app.00390.2017 706 ACTA PALAEONTOLOGICA POLONICA 62 (4), 2017 A 1 u B sh Hon Kumamoto u ok 4 hik 5 u S 6 sh yu 3 East China Sea K 2 Maeshima Bungo Channel 100 km C Maeshima D Mak i Is Bullman land Creek East Twin River d n la Is ra u o h os G Canyon River West Fork 7 of Grays River 2000 m 100 km Fig. 1. A. Map showing some of the fossil seep localities bearing thyasirids examined in this study. Detailed maps of Amakusa area, Kyushu, Japan (B, C), Washington State, USA (D). 1, Colesbukta area, Spitsbergen, Svalbard; 2, Maeshima, Amakusa area, Kyushu, Japan; 3, Tanami, Honshu, Japan; 4, Hokkaido, Japan; 5, Washington State, USA; 6, Montrose, Nebraska, USA; 7, James Ross Basin, Seymour Island, Antarctica. After Campbell 2006 (A) and Goedert and Benham 1999 (D). For detailed list of localities discussed, the reader is refered the Material section, and references therein. on fossil seeps, the taxonomy of thyasirids in these habitats University of California Museum of Paleontology, Berkeley, remains poorly understood. The purpose of this paper is to USA; UMUT, University Museum, University of Tokyo, improve the current knowledge of fossil seep-inhabiting Tokyo, Japan; USNM, United States National Museum thyasirids using newly collected material and museum col- of Natural History, Washington, USA; ZPAL, Institute of lections. Due to an overwhelming number of Neogene seep Paleo biology, Polish Academy of Sciences, Warsaw, Poland. deposits, especially in Japan and the Russian Far East, the current study is restricted to more manageable Cretaceous and Paleogene occurrences. Material Institutional abbreviations.—CSUN, California State This study is based on a collection of specimens from University at Northridge, USA; GPIBo, Steinmann-Institut Cretaceous–Oligocene localities worldwide (Figs. 1, 2). The für Geologie, Mineralogie und Paläontologie, Universität majority of these localities have already been described; Bonn, Germany; JUE, Joetsu University of Education, therefore we only briefly outline the localities and provide Japan; LACMIP, Natural History Museum of Los Angeles references to more detailed descriptions. The localities are County, Los Angeles, USA; MMH; Natural History Mu- listed below in an alphabetical order. seum of Denmark, Geological Museum, Copenhagen, Den- Bear River, southwestern Washington State, USA.— mark; NRM, Swedish Museum of Natural History (Natur- Large seep deposit in an abandoned quarry on the south side historiska riksmuseet), Stockholm, Sweden; PMO, Natural of Bear River in Pacific County, western Washington State, History Museum, University of Oslo, Norway; UCMP, embedded in upper Eocene strata of “Siltstone of Cliff Point” HRYNIEWICZ ET AL.—CRETACEOUS AND PALEOGENE THYASIRID BIVALVES 707 Ma 23.0 Oligocene 33.9 Creek Creek East Twin River R Yayoi Murdock Tappu Eocene Kami-Atsunai S 4, Satsop River Tanami Bullman Kiritachi Paleogene Canyon River Bear River loc. 16504, Canyon River River 56.0 Colesbukta Whiskey Creek Paleocene LACMIP James Ross Basin 66.0 Humptulips Maastrichtian 72.1 Montrose West Fork of Grays River Campanian Maeshima 83.6 Santonian Coniacian 89.8 Late Cretaceous Turonian 93.9 Cenomanian 100.5 Western Kyushu Honshu AntarcticaSvalbard Hokkaido WashingtonState Interior Seaway Fig. 2. Geological ages of the fossil seep localities bearing thyasirids examined in this study. (LACMIP loc. 5802). It contains a diverse fauna dominated occurrences later identified as seep deposits and wood-rich by Bathymodiolus willapaensis; the thyasirids reported sediments (Hryniewicz et al. 2016). The fauna is dominated herein are quite rare (Goedert and Squires 1990; Squires and by C. conradii associated with diverse background species, Goedert 1991; Goedert and Benham 2003; Kiel 2010). chiefly mollusks. Bullman Creek, northwestern Washington State, USA.— East Twin River, northwestern Washington State, USA.— Cold seep limestone found as float on beach terrace approxi- Block of cold-seep limestone found as float along base of mately 1 km east of the mouth of Bullman Creek in Clallam bluff approximately 110 m north and 490 m west of the south- County, northwestern Washington State, derived from the east corner of Section 24, T. 31 N., R. 10 W according to US lower Oligocene Jansen Creek Member of the Makah For- public land description system, approx. 1.6 km east of East ma tion; coordinates: 48°20.798’ N, 124°31.223’ W. Twin River, Clallam County, Washington State. The block Canyon River, western Washington State, USA.—Large comes from the upper part of the Pysht Formation and is of cold seep carbonate block with large thyasirid bivalves ex- late Oligocene age (Nesbitt et al. 2013). posed by natural etching. Found as float on gravel bar, east Humptulips Formation, western Washington State, bank of Canyon River, approximately 100 m upstream from USA.—Our material comes from two distinct localities bridge, coordinates: 47°18.166’ N, 123°30.567’ W; SE ¼ of from the middle Eocene Humptulips Formation in