A new genus and species of sphaeromatid (Crustacea: Isopoda) from the Lower Cretaceous (Aptian) Sierra Madre Formation, Chiapas, Mexico. (March 2022)

• Record Type: Journal Article
• Authors: Vega, Francisco J.; Bruce, Niel L.; Serrano-Sánchez, María de Lourdes; Coutiño, Marco A.
• Is Part Of: Journal of South American earth sciences. Volume 114(2022)
• Publication Date: 2022-03
• Subjects: Crustacea sphaeromatidae -- Isopoda -- new genus -- Lower Cretaceous -- Chiapas -- Mexico; Geology -- Latin America -- Periodicals; Earth sciences -- Latin America -- Periodicals; Geology -- Antarctica -- Periodicals; Earth sciences -- Antarctica -- Periodicals; Geology -- Caribbean Area -- Periodicals; Earth sciences -- Caribbean Area -- Periodicals; Géologie -- Amérique latine -- Périodiques; Sciences de la terre -- Amérique latine -- Périodiques; Géologie -- Antarctique -- Périodiques; Sciences de la terre -- Antarctique -- Périodiques; Géologie -- Caraïbes (Région) -- Périodiques; Sciences de la terre -- Caraïbes (Région) -- Périodiques; Earth sciences; Geology; Antarctica; Caribbean Area; Latin America; Periodicals; 550.5
• DOI: 10.1016/j.jsames.2022.103720
• Languages: English
• ISSNs: 0895-9811

Abstract

Abstract: Chiapasphaera cretacea Vega and Bruce gen. et sp. nov. is described from the dolomitic laminar plattenkalk deposits of the Aptian Sierra Madre Formation at El Espinal quarries, Chiapas, Mexico. The new isopod is represented by more than 50 specimens of diverse size, but with a mean length of about 10 mm and 0.4 mm width. Isopods are preserved as corpses in dorsal and ventral views, as well as a moults and rolled individuals, The morphology resembles that of the extant genus Gnorimosphaeroma, but differs principally in having five visible pleonites, warranting the erection of a new genus and new species. Poor preservation of appendages prevents a more detailed description, but details of pereon, pleon, pleotelson and uropods are clear enough to offer important taxonomic features. This is the sixth isopod species reported from the El Espinal quarries. Highlights: New genus and species of Cretaceous isopod from Mexico. Detailed morphology due to unique preservation. Numerous specimens preserved in different positions. The most diverse and abundant fossil peracarid locality in the world. Discussion on the paleoenvironment.