Review and additions to the Maastrichtian (Late Cretaceous) crustacea from Chiapas, Mexico

Re-evaluation of the taxonomic status of Vegaranina (Crustacea: Raninidae) from the Late Cretaceous of Cuba, with description of a new species

“…in America and Europe during the late Cretaceous support the hypothesis that the genus originated in the Tethys region (Feldmann et al 1996, Schweitzer et al 2007. It also indicates that the genus was widely dispersed, with at least 3 species living throughout the Tethys (Van Bakel et al 2012, Vega et al 2018.…”

“…The differences observed between the specimens from Cuba and Mexico cannot be explained by ontogenetic changes because the characters that distinguish the species are stable in individuals of distinct size in each taxon (Feldmann et al 1996, Vega et al 2018; also, the size of the paratypes of the Cuban species overlap with the size of V. precocia. Although the sex of the specimens from both species has not been determined, it seems unlikely that the seven fossil specimens of V. precocia reported by Vega et al (2018) represent one sex and the three Cuban specimens the other. We consider that with the exception of the differences in spine size, sexual dimorphism fails to be the cause of the difference between other characters.…”

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“…The wide distribution of the Icriocarcininae during the latest Cretaceous is confirmed by the occurrence of Icriobranchiocarcinus rodas. Other records for this extinct subfamily at the K/ Pg event includes: Branchiocarcinus cornatus Feldmann and Vega in Vega et al (1995) in the lower Maastrichtian Cárdenas Formation of San Luis Potosí, Mexico; B. flectus (Rathbun, 1923) in the Maastrichtian of Mississippi and New Jersey, USA (Phillips et al, 2013;Landman et al, 2007); B. pacificus Nyborg, Ossó and Vega, 2014, from the latest Maastrichtian of California (USA) (Nyborg et al, 2014); Icriocarcinus xestos Bishop, 1988, in the lower Maastrichtian El Rosario (Baja California, Mexico), the lower Maastrichtian of Baja California (Mexico) and the Point Loma Formation, California; and Icriobranchiocarcinus tzutzu from the lower Maastrichtian of Chiapas (Vega et al, 2018). This suggests that the Icriocarcininae (possibly derived from the Lithophilacinae during the Cenomanian of Europe), had a major radiation at the end of the Cretaceous Period, reaching an extensive distribution and a wide diversity of shapes, sizes, and morphological details that suggest a high ende-mism of the genera and species of this family, especially during Maastrichtian times in North America (Figure 6) and possibly in Europe, too.…”

“…Genera included.-IcriocarcinusBishop, 1988; Branchiocarcinus Feldmann and Vega, in Vega et al (1995); Icriobranchiocarcinus Vega, 2018 inVega et al (2018), and possibly CancrixanthoVan Straelen, 1934. Genus Icriobranchiocarcinus Vega, 2018 inVega et al, 2018 Type species.-Icriobranchiocarcinus tzutzuVega, 2018(in Vega et al, 2018, fig. 10.1-10.7, by monotypy).…”

Biostratigraphy and paleoenvironment of Maastrichtian foraminiferal assemblages from a succession located NW of Tuxtla Gutiérrez, Chiapas (SE Mexico)

“…Macrofossils from the area are abundant and diverse: rudist bivalves have been reported from both formations (Müllerried, 1931(Müllerried, , 1934Chubb, 1959;Alencáster, 1971;Alencáster and Pons, 1992;Pons et al, 2016Pons et al, , 2019; inoceramid bivalves and/or ammonites from the Ocozocoautla Formation (Michaud, 1984;Bolaños and Buitrón, 1984;Alencáster and Omaña, 2006;Pons et al 2016); bivalves and gastropods (Buitrón et al, 1995); corals (Filkorn et al, 2005;Löser, 2012), crustaceans (Vega et al, 2001(Vega et al, , 2018Hyžný et al, 2013), and vertebrate remains (Carbot-Chanona and Rivera-Sylva, 2011;Carbot-Chanona and Than-Marchese, 2013). Larger foraminifera are abundant in both the Ocozocoautla and Angostura formations (Ayala-Castañares, 1963;Michaud, 1987;Rosales-Domínguez et al, 1997;Omaña and Pons, 2003;Vicedo et al, 2013).…”