Equinoideos del Cretácico Tardío del Norte de Coahuila, México

Abstract

ResumenEn el presente trabajo se describen diez especies de equinodermos fósiles que han sido colectados en varios afloramientos de la Formación Austin (Cretácico Superior) localizados en los arroyos El Freno y El Tecolote, dentro del municipio de Jiménez, norte de Coahuila. La presencia de los ammonites Scaphites hippocrepis y Delawarella delawarensis en las secciones estudiadas permite asignar a estas capas una edad de Campaniano inferior. Algunos taxa aquí reportados como Cidaris texanus Clark, Salenia mexicana Schluter, Holectypus sp., Heteraster texanus Röemer y Diplodetus sp. son conocidos en varias localidades de México. Por otra parte, Cidaris splendens Morton, Diplopodia hilli Clark, Orthopsis casanovai Cooke, Micraster uddeni Cooke, Mecaster batnensis (Coquand), y Diplodetus sp. se reportan por primera vez para México en este trabajo, por lo que se amplía su rango de distribución en la parte oeste del Océano Proto-Atlántico. Por otra parte, la presencia de las especies Cidaris texanus, Cidaris splendens, Selenia mexicana y Heteraster texanus en capas de la Formación Austin amplía el rango de distribución temporal de estas especies dentro del Campaniano inferior en México, lo que podría contribuir en futuras interpretaciones bioestratigráficas de todo el Sistema Cretácico basadas en equinoideos.Palabras clave: Cretácico Superior, Campaniano inferior, Grupo Austin, equinoideos fósiles, noreste de México. Abstract Ten species of fossil echinoids are herein described from different outcrops of the Austin Formation (Upper Cretaceous) in the El

New Echinoid (Spatangoida: Toxasterinidae) from the Campanian of Coahuila, Northeastern Mexico

“…In a previous work carried out by Vega et al (2013) at Austin Formation, in the vicinity of the study area, he reported the presence of the ostreids Phrysaea (Gryphaea) aucella and Exogyra laeviscula, the ammonoid Parapuzosia boisei and two species of the genus Menabites as well as the crustacean (Decapoda) species Enoploclytia tepeyacensis. According to Silva-Martínez et al (2014) the presence of the ammonite Delawarella delawarensis (Morton, 1841) along the studied section supports the assignment of a Lower Campanian age for this unit.…”

“…The description of three echinoids specimens of the genus Diplodetus reported by Silva-Martínez et al (2014) Continental shelf environments, the presence of soft seafloor, and organic matter in the sediment, which represent a food source for endobenthonic organisms, are the main features that define a scenario that contribute to the developement of detritivore organism, such as D. brisenoi in the Austin Formation of northeastern Mexico.…”

“…It has been described in Paleocene rocks of Madagascar, Ukraine and Western Europe (Cotteau, 1877). The presence of D. brisenoi in northeastern Mexico, represent the only known record for the genus in Mexico (Silva-Martínez et al, 2014) and the second one in America, and it is also the most austral record for this continent (Figure 7). Paleoecology and paleobiology of the genus Diplodetus: In the Northeastern of Mexico, the Austin Formation has been widely described by different authors at different localities (Shumard, 1860;Reeside, 1927;Adkins, 1930;Young, 1963;Carrasco, 1963Carrasco, , 1969Taff, 1892;Santamaría-Zabala, 1991;Sohl et al, 1991;Eguiluz de Antuñano, 2001;Escalante et al, 2002;Romo-Ramírez et al, 2002;Santiago et al, 2003;Stinnesbeck et al, 2005;Myers, 2010;Silva-Martínez et al, 2014).…”

“…It was deposited under conditions of an inner/medium continental shelf environment. The stratigraphic age for this unit was ranked from Coniacian to Lower Campanian (Silva-Martínez et al, 2014). The Early Campanian was a time of transgressions that influenced the Northeastern of Mexico, it carried a major influx of terrigenous sediment into the Gulf of Sabinas (Sohl et al, 1991).…”

“…This genus is also known in Upper Cretaceous rocks from Belgium (Jagt, 2000), Germany (Newman et al, 2000), Netherlands (Jagt, 2000), Spain (Rehfeld and Ernest, 1998) and it is less common from the Paleocene of Madagascar, Ukraine and Western Europe (Cotteau, 1877). In Mexico, the only known record for this genus was reported by Silva-Martínez et al (2014) in outcrops of the Austin Formation (Lower Campanian: Upper Cretaceous), at the localities of Arroyo El Freno and Arroyo El Tecolote, in the municipality of Jiménez, Coahuila. The present work provides a more detailed description of the specimens reported by Silva-Martínez (2014) in order to raise Diplodetus brisenoi as a new echinoid fossil species from Lower Campanian of Coahuila, Northeast of Mexico, and to give a short comment concerning its paleoecological significance within the Austin Formation at the study area.…”