Campanian rudists (Hippuritida, Bivalvia) from Costa Rica (Central America)

Abstract

The Campanian rudist fauna identified from the localities Playa Panamá, Santa Rosa National Park, Colorado de Abangares, and Bolsón in Guanacaste Province, Costa Rica, is composed of the antillocaprinidsAntillocaprinasp. aff.A. suboccidentalisChubb, 1967,Antillocaprinasp. and Antillocaprinidae indet.; the multiple-fold hippuritidsBarrettia moniliferaWoodward, 1862,Parastroma trechmanniChubb, 1967, and cf.Whitfieldiella gigas(Chubb, 1955); the plagioptychidsPlagioptychus trechmanniChubb, 1956,Plagioptychussp. cf.P. zansiChubb, 1956,Mitrocaprina costaricaensisnew species,Mitrocaprina multicanaliculataChubb, 1956, and Plagioptychidae indet.; and the radiolitidsRadiolitessp. aff.R. multicostata(Adkins, 1930),Alencasteritesnew genusmooretownensis(Trechmann, 1924),Bournonia?tetrahedron(Chubb, 1967),Chiapasellasp.,Guanacastea costaricaensisnew genus new species, cf.Potositessp. aff.P. tristantorresiAlencáster and Pons in Pons et al., 2010, and aff.Thyrastylonsp. Although some differences in rudist diversity and sedimentary setting were observed among localities, most species indicate the same age for all occurrences, which correspond to the Campanian, probably mid-Campanian. Radiolitid specimens appear better preserved than those of other taxa and are thus discussed more in detail. Both the number of radiolitid genera exclusively known from the New World, and reasonable doubts about the correct attribution of some New World species to Old World genera, indicate important differences between rudist faunas at both sides of the Atlantic (Mediterranean and American Tethys, respectively) during the Late Cretaceous.

Rapid vertical motions and formation of volcanic arc gaps: Plateau collision recorded in the forearc geological evolution (Costa Rica margin)

“…Here, the oldest overlap lithologies correspond to the middle Campanian, shallow-water El Viejo Fm. (Denyer et al, 2014b;Pons et al, 2016; Figure 3a), the age of which provides a solid constraint on the accretion timing of the Nicoya Complex (Figures 7c and 8b). These considerations discard the possibility that significant parts of the plateau lithologies of the Nicoya Peninsula were accreted after the Campanian.…”

“…In the NW Nicoya Peninsula, plateau basalts dated at 110 Ma are surrounded by rocks dated at 92-83 Ma . (Denyer et al, 2014b;Pons et al, 2016;Figure 3a), the age of which provides a solid constraint on the accretion timing of the Nicoya Complex (Figures 7c and 8b). 2.…”

“…Figure3) present one unique, middle Campanian faunal assemblage(Pons et al, 2016), advocating a middle Campanian final assembly of the terranes. The rudist-bearing deposits were also reworked in mass flows the matrix of which contains Campanian planktonic Foraminifera such as Globotruncanita elevata (Santa Ana Fm.…”

“…The composite range of each species was obtained by stacking partial ranges from the literature (Data S2). ; Schmidt-Effing, 1974;Seyfried & Sprechmann, 1985;Baumgartner-Mora & Denyer, 2002;Denyer et al, 2014a;Pons, Vicens, & Schmidt-Effing, 2016); (2) cross-stratified arenites and conglomerates (Quebrada Pavas Fm. (b) Scanning electron microscopy images of radiolarians recovered from the Loma Chumico Formation.…”

“…In places, uplift caused the subaerial exposure of the forearc basements (Manzanillo Terrane for the Tempisque Forearc Basin, Santa Elena arc for the Sandino Forearc Basin). The rudist-rich deposits overlying the three terranes(Nicoya, Manzanillo, Santa Elena; Figure 3) present one unique, middle Campanian faunal assemblage(Pons et al, 2016), advocating a middle Campanian final assembly of the terranes. These deposits consisted of trough cross-stratified, shallow-shelf arenites and conglomerates (Quebrada Pavas Fm.)…”