Cetorhinuscf.C. maximus(Gunnerus) (Lamniformes: Cetorhinidae), A Basking Shark from the Late Miocene Empire Formation, Coos Bay, Oregon

Abstract

The family Cetorhinidae Gill includes one extant genus, Cetorhinus Blainville, and a single living species, the basking shark, C. maximus (Gunnerus). Basking sharks are coastal pelagic to oceanic with circumglobal distribution in boreal to warm-temperate waters of the continental and insular shelves. Second only in size to the whale shark, Rhincodon typus, basking sharks attain a maximum total length of 12 to 15 m (although generally not exceeding 9.8 m), and are planktivorous, feeding by filtering copepods, barnacles, decapod larvae and fish eggs from the water. The first Tertiary records of undisputed cetorhinids are from the middle Eocene of Antarctica, possibly the middle Eocene of Russia, and the late Eocene of Oregon. Eocene cetorhinids are referred to Keasius taylori, and Oligocene through early Miocene basking sharks are traditionally assigned to Keasius parvus. The earliest occurrence of Cetorhinus in the northeastern Pacific is early Miocene, and fossils attributed to this genus are relatively common in middle Miocene through Pleistocene marine sediments of Oregon, California, and Baja California, Mexico. Late Miocene and younger Cetorhinus are conventionally placed in the extant species, C. maximus. Late Miocene fossils of a basking shark from the Coos Conglomerate Member of the Empire Formation, Oregon, were collected in 1972 by students from the University of California, Berkeley. Associated vertebrae and gill rakers compare favorably in size and overall morphology with those of adult Recent C. maximus. Based on correlations of vertebral and gill raker dimensions with the total length for Recent C. maximus, the Empire basking shark is estimated to have been between 4.5 and 5.75+ m in total length. Although gill rakers and vertebrae from the Empire Formation compare favorably with those of C. maximus, a definitive identification requires dentition. The occurrence of Cetorhinus cf. C. maximus in the late Miocene of Oregon is consistent with other late Miocene records of this species in California and Chile. C. maximus may range no earlier than late Miocene in the eastern North Pacific.

Heterodonty and ontogenetic shift dynamics in the dentition of the tiger shark Galeocerdo cuvier (Chondrichthyes, Galeocerdidae)

“…Gomes and dos Reis ( 1990 ) even found a reversed tooth file in an embryonic sand tiger shark Carcharias taurus . Other shark species with documented reversed tooth files include the whitetip reef shark Triaenodon obesus (Rüppell, 1837 ), and the leopard shark Triakis semifasciata Girard, 1855 (Reif, 1980 ), the night shark Carcharhinus signatus (Poey, 1868 ) (Raschi et al, 1982 ), the gulper shark Centrophorus granulosus (Bloch & Schneider, 1801 ) (Smith et al, 2013 ), the basking shark Cetorhinus maximus (Gunnerus, 1765 ) (Welton, 2013 ), the nursehound Scyliorhinus stellaris (Berio, 2021 ), the sharptooth lemon shark Negaprion acutidens (Rüppell, 1837 ) (R. Kindlimann, pers. obs.…”

A Review of the Paleobiology of Some Neogene Sharks and the Fossil Records of Extant Shark Species

“…Cetorhinus maximus (Gunnerus) Fossil record: Following Hovestadt & Hovestadt-Euler [62], this extant species first appeared in the Middle Miocene, whereas Welton [108] cited the Late Miocene as the earliest occurrence. Material has been referred to this taxon from the Early to Middle Miocene: Japan (Saitama) [109]; Middle Miocene: Czech Republic (Kienberg) [110]; Late Miocene: USA (Oregon) (as "cf.")…”

“…Material has been referred to this taxon from the Early to Middle Miocene: Japan (Saitama) [109]; Middle Miocene: Czech Republic (Kienberg) [110]; Late Miocene: USA (Oregon) (as "cf.") [108], USA (California) [111]; Late Miocene: Germany (Sylt, Lower Saxony [112,113]; Late Miocene to Early Pliocene: Chile (El Rincón) [114], Netherlands (Winterswijk-Almelo) [115]; Early Pliocene: Belgium (Kallo) [116], France (Le-Puget-sur-Argens, Anvers) [84,117]; Late Pliocene: Italy (Tuscany) [85].…”

A Review of the Palaeobiology of Some Neogene Sharks and the Fossil Record of Extant Shark Species

“…Dalatiidae Gray, 1851 Dalatias licha (Bonnaterre, 1788) Fossil record: Miocene: Italy (Sardinia) (Comaschi Caria 1973); Early to Middle Miocene: France (Vaucluse, Southern France) (Ledoux 1972;Cappetta 1975;Brisswalter 2009), Colombia (Guajira Peninsula) (Carrillo-Briceño et al 2016b;2019, both as "cf. "); Middle Miocene: South Korea (Yun 2021), Early Miocene to early Pliocene: Japan (Itoigawa et al 1985;Yabe & Hirayama 1998;Tanaka 2001;Suzuki 2005) Lamniformes Berg, 1958Cetorhinidae Gill, 1862 Cetorhinus maximus (Gunnerus, 1765) Fossil record: Following Hovestadt & Hovestadt-Euler (2010) this extant species first occurs in the Middle Miocene, whereas Welton (2013b) cited Late Miocene as the earliest occurrence.…”

“…Fossil record: Early to Middle Miocene: Japan (Saitama) (Uyeno et al 1983); Middle Miocene: Czech Republic (Kienberg) (Schultz et al 2010); Late Miocene: USA (Oregon) (Welton 2013b, as "cf"), USA (California) (Powell et al 2019); Late Miocene: ?Germany (Sylt, Lower Saxony) (Lienau 1987;Menzel et al 1994); Late Miocene to Early Pliocene: Chile (El Rincón) (Long 1993), Netherlands (Winterswijk-Almelo) ( Van den Bosch et al 1975); Early Pliocene: Belgium (Kallo) (Herman 1979), France (Le-Puget-sur-Argens, Anvers) (Leriche 1908;Cappetta & Nolf 1991) (Suárez et al 2006); Middle Miocene-Pliocene: Chile (Northern Chile) (Hoffmeister & Villafaña 2023); Late Miocene-Early Pliocene: Venezuela (Aguilera & de Aguilera 2001); Early Pliocene: USA (North Carolina) (Purdy et al 2001); Late Pliocene: Italy (Tuscany) (Cigala Fulgosi 2009).…”