A Gigantic Shark from the Lower Cretaceous Duck Creek Formation of Texas

Author Contributions Conceived and designed the experiments: JAF SNS JAD-F. Analyzed the data: JAF SNS. Wrote the paper: JAF SNS. Site data for OMNH V1727 are available by request from the department of vert. paleontology at the (SN)OMNH.Three large lamniform shark vertebrae are described from the Lower Cretaceous of Texas. We interpret these fossils as belonging to a single individual with a calculated total body length of 6.3 m. This large individual compares favorably to another shark specimen from the roughly contemporaneous Kiowa Shale of Kansas. Neither specimen was recovered with associated teeth, making confident identification of the species impossible. However, both formations share a similar shark fauna, with Leptostyrax macrorhiza being the largest of the common lamniform sharks. Regardless of its actual identification, this new specimen provides further evidence that large-bodied lamniform sharks had evolved prior to the Late Cretaceous.Ye

Campanian (Late Cretaceous) ammonites from the upper part of the Anacacho limestone in South-Central Texas

The ammonite assemblage from the upper part of the Anacacho Limestone in Medina County in south-central Texas consists of Pachydiscus (Pachydiscus) travisi (ADKINS, 1929), Pachydiscus (P.) sp., Pachydiscus (P.) streckeri (ADKINS, 1928), Hoplitoplacenticeras (H.) marroti (COQUAND, 1859), Eubostrychoceras reevesi (YOUNG, 1963), Bostrychoceras polyplocum (ROEMER, 1841), Lewyites clinensis (ADKINS, 1929), Baculites taylorensis ADKINS, 1929, and Trachyscaphites spiniger porchi (ADKINS, 1929). Several of these species are also found in the Pecan Gap Chalk in central and northeastern Texas and in the basal part of the Demopolis Formation in Mississippi and Alabama. The fauna is probably contemporaneous with the Baculites asperiformis zone in the U.S. Western Interior, which lies in the lower part of the middle Campanian in the sense of the Western Interior threefold division of the Campanian. In terms of the European twofold division of the Campanian, the fauna lies in the lower part of the upper Campanian

Campanian ammonites from the Annona Chalk near Yancy, Arkansas

Ammonites are abundant in the phosphatic base of the Annona Chalk (Campanian) near Yancy in Hempstead County, Arkansas. Twelve species are described. The diverse Nostoceras association is typical of Gulf Coast upper Campanian rocks but Didymoceratoides is a Western Interior upper middle Campanian genus. Nostoceras (N.) monotuberculatum n.sp., however, is known from a single specimen from the basal upper Campanian Didymoceras stevensoni zone in Colorado. -from Author

Upper campanian (upper cretaceous) ammonites from the Marshalltown Formation-Mount laurel boundary beds in Delaware

New collections from the Marshalltown Formation and basal Mount Laurel Sand along the Chesapeake and Delaware Canal in Delaware clarify the ammonite dating of the interval. The Marshalltown Formation yields Pachydiscus (Pachydiscus) sp., Menuites portlocki (Sharpe, 1855) complexus (Hall and Meek, 1856), a subspecies restricted to the Baculites gregoryensis and Baculites scotti zones in the Western Interior of the United States, and Didymoceras binodosum (Kennedy and Cobban, 1993a) known only from the B. scotti zone of the Western Interior and correlatives in Arkansas and Texas. The basal part of the Mount Laurel Sand contains a complex assemblage preserved as phosphatic molds: Nostoceras (Nostoceras) monotuberculatum Kennedy and Cobban, 1993a, Nostoceras (N.) sp., Didymoceras platycostatum (Kennedy and Cobban, 1993b), D. stevensoni (Whitfield, 1877) (previously thought to be from the Marshalltown) and Exiteloceras jenneyi (Whitfield, 1877). The last two are index species of their eponymous zones in the Western Interior. This sequence is compatible with ammonites from the Wenonah Formation, which lies between the Marshalltown and Mount Laurel to the north and contains ammonites indicative of the Baculites scotti zone, and the fauna from higher in the Mount Laurel Sand, which includes elements of the Didymoceras cheyennense and Baculites compressus zones of the Western Interior sequence

Upper Cretaceous ammonites from the Coon Creek Tongue of the Ripley Formation at its type locality in McNairy County, Tennessee

The ammonite fauna of the Coon Creek Tongue of the Ripley Formation at its type locality in McNairy County, Tennessee, is described. This fauna has generally been placed in the lower Maastrichtian, but it is here attributed to the upper Campanian, inasmuch as two of the characteristic species present, N.(N.) hyatti and J. nodosus, are confined to the upper Campanian in western Europe. A younger ammonite fauna of early Maastrichtian age is present, however, in the Coon Creek Tongue of Mississippi, Alabama, and Georgia. -from Author

The Upper Cretaceous dimorphic pachydiscid ammonite Menuites in the Western Interior of the United States

Highly dimorphic pachydiscid ammonites are fairly abundant in Montana, South Dakota, Wyoming, and Colorado, and a few specimens are known from Utah and New Mexico. Two chronologic species are recognized, each represented by small adults (microconchs) and large adults (macroconchs). Microconchs have been assigned to Menuites Spath, 1922, whereas macroconchs have usually been assigned to Anapachydiscus Yabe and Shimizu, 1926. Both forms are considered Menuites in the present report. -from Author

New records of the ammonite subfamily Texanitinae in Campanian (Upper Cretaceous) rocks in the Western Interior of the United States

All known members of the stratigraphically important and cosmopolitan ammonite subfamily Texanitinae are documented from the Campanian rocks of the Western Interior of the United States for the first time. Submortoniceras tequesquitense Young, 1963, occurs in the upper part of the Mancos Shale in Santa Fe County in north-central New Mexico; Menabites (Delawarella) vanuxemi (Morton, 1830) occurs in the Mancos Shale at Sandoval County, New Mexico; and Menabites (Delawarella) danei Young, 1963, occurs at the top of the Apache Creek Sandstone Member of the Pierre Shale in Pueblo County, Colorado. -Author

Upper Cretaceous (Maastrichtian) ammonites from the Nostoceras alternatum zone in southwestern Arkansas

Calcareous concretions in the Nacatoch Sand in Hempstead County, Arkansas, yield abundant fossils of the lower Maastrichtian Nostoceras alternatum zone, previously recognized in Mississippi, Alabama, and Georgia. The fossils include Inoceramus regularis d'Orbigny, 1842, Pseudophyllites indra (Forbes, 1846), Brahmaites sp., Sphenodiscus sp., Nostoceras (Nostoceras) alternatum (Tuomey, 1854), Solenoceras nitidum Cobban, 1974, Baculites claviformis Stephenson, 1941, and Jeletzkytes sp. A and sp. B. The N. alternatum zone may correlate with the Baculites clinolobatus zone in the Western Interior. -Author

Maastrichtian ammonites from the Hornerstown Formation in New Jersey

The base of the Paleocene Hornerstown Formation at the Inversand pit and certain other localities in New Jersey yields a diverse phosphatised fauna of Maastrichtian age, including the ammonites Pachydsicus (Neodesmoceras) mokotibensis Collignon, 1952, Sphenodiscus lobatus (Tuomey, 1854), Baculites spp., and Eubaculites carinatus (Morton, 1834). S. lobatus is known from the older Red Bank Sand and Tinton Sand in New Jersey; the other species are known only from the basal Hornerstown. Occurrences at the Inversand pit are regarded as either reworked or remainie, although details of Cretaceous/Paleocene boundary events have been destroyed by pervasive burrowing that pipes the Hornerstown down into the underlying Navesink Formation