Taphonomy and ontogeny of the brachyuran crab Exucarcinus gonzagai, from the Lower Cretaceous (Aptian) Romualdo Formation, Araripe Basin, NE Brazil

Author(s)

Matos, Suzana Aparecida ^[1] ; Castilho, Antonio Leao ^[1] ; Cadeira do Prado, Ludmila Alves ^[2] ; Bondioli, Joao Guedes ^[3] ; Varejao, Filipe Giovanini ^[4] ; Custodio, Michele Andriolli ^[5] ; Fuersich, Franz Theodor ^[6] ; Assine, Mario Luis ^[7] ; Simoes, Marcello Guimaraes ^[1]

Affiliation

^[1] Univ Estadual Paulista, Inst Biociencias, BR-18618970 Botucatu, SP - Brazil

^[2] Univ Fed Pemarnbuco, Ctr Tecnol & Geociencias, Dept Geol, BR-50740533 Recife, PE - Brazil

^[3] Univ Sao Paulo, Inst Geociencias, BR-05508080 Sao Paulo, SP - Brazil

^[4] Univ Fed Ouro Preto, Dept Geol, Escola Minas, BR-35400000 Ouro Preto, MG - Brazil

^[5] Univ Fed Amazonas, Inst Ciencias Exatas, Dept Geociencias, BR-69077000 Manaus, Amazonas - Brazil

^[6] Friedrich Alexander Univ Erlangen Nurnberg, FG Palaoumwelt, GeoZentrum Nordbayern, Loewenichstr 28, D-91054 Erlangen - Germany

^[7] Univ Estadual Paulista, Inst Geociencias & Ciencias Exatas, Dept Geol, Campus Rio Claro, BR-13506900 Rio Claro, SP - Brazil

• Document type: Journal article
• Source: Journal of South American Earth Sciences; v. 111, NOV 2021.
• Web of Science Citations: 0

Abstract

Brachyurans played important ecological and evolutionary roles in the marine benthic communities of the past and were the components of the Mesozoic Decapod Revolution. Therefore, the search for their fossil remains is fundamental to understanding the composition, diversity, and ecological structure of Mesozoic marine benthic communities. Brachyuran remains are uncommon in the decapod record of the Aptian Romualdo Formation in the Araripe Basin. In this context, we recorded and described new occurrences of Exucarcinus gonzagai, preserved in shales from the middle portion of the Romualdo Formation, near the city of Jardim in the State of Cear ` a. Comparisons between these new specimens and former specimens from the Exu locality, State of Pernambuco, including the type material, allowed us to recognize, for the first time, three distinct ontogenetic stages (i.e., informally referred as I, II, and III). Throughout ontogenetic development, the carapace becomes wider and spinier. Stage III carapaces exhibit a large number of grooves, although the grooves are poorly impressed, and some are pitted. Growth also resulted in better-developed orbital lobes and fissures. In addition, the preservation of some anatomical structures is highly influenced by the carapace fossilization process (i.e., molds or cuticles), including the tubercles, grooves, and spines. Unfortunately, those characters that can vary according to onto genetic development or fossilization are commonly used in the systematic and phylogenetic decisions of the group. Hence, it is advisable to consider these changes whenever possible to avoid the erection of taphotaxons and mistaken phylogenetic decisions. (AU)

• FAPESP's process: 14/00519-9 - Centralities of night-time leisure in the city of São Carlos-SP and the interface relations
• Grantee: Tiago Ferreira Lopes Machado
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• FAPESP's process: 17/20803-1 - Stratigraphic and Paleoenvironmental Context of the Macroinvertebrate Assemblages of the Romualdo Formation, Cretaceous, Araripe Basin, and its Paleogeographic Implications
• Grantee: Suzana Aparecida Matos da Silva
• Support Opportunities: Scholarships in Brazil - Post-Doctoral