RESUMO
ABSTRACT Clupeomorphs are found in many assemblages of the northeastern Brazil, whose ages range from the Neocomian to Paleogene. Ten species were described. Among them †Scutatuspinosus itapagipensis, a torpedo-like fish found in shales of the Marfim Formation from Bahia, remains poorly known. At first it was positioned within †Scutatuspinosinae and indicated as closely related to †Diplomystus. Diagnoses for the subfamily and genus were based on certain characters masking relationships. Recently it was placed in †Ellimmichthyiformes, but its systematic position remains controversial. We furnish additional data and restorations together with a parsimony analysis with TNT program, using 60 unordered and unweighted characters from selected species of 13 genera. Our analysis produced 12 trees with 158 steps, a consistency index (CI) of 0.44 and retention index (RI) of 0.52. Low support indices still indicate insufficient data for many taxa and uncertain status for clades. According to the majority rule consensus, †Scutatuspinosus itapagipensis is placed within a "†paraclupeine" group with †Ezkutuberezi carmenae, †Ellimma branneri, †Ellimmichthys longicostatus, and †Paraclupea chetunguensis. Its minimum age and position among †paraclupeids indicate an early history of the group older than it was thought to be, supporting a biogeographical hypothesis based on generalized track from China to northeastern Brazil during the Lower Cretaceous.
Assuntos
Animais , Torpedo/anatomia & histologia , Filogenia , Osso e Ossos/anatomia & histologia , Brasil , Torpedo/classificação , Tamanho Corporal , Filogeografia , Fósseis/anatomia & histologiaRESUMO
Clupeomorphs are found in many assemblages of the northeastern Brazil, whose ages range from the Neocomian to Paleogene. Ten species were described. Among them Scutatuspinosus itapagipensis, a torpedo-like fish found in shales of the Marfim Formation from Bahia, remains poorly known. At first it was positioned within Scutatuspinosinae and indicated as closely related to Diplomystus. Diagnoses for the subfamily and genus were based on certain characters masking relationships. Recently it was placed in Ellimmichthyiformes, but its systematic position remains controversial. We furnish additional data and restorations together with a parsimony analysis with TNT program, using 60 unordered and unweighted characters from selected species of 13 genera. Our analysis produced 12 trees with 158 steps, a consistency index (CI) of 0.44 and retention index (RI) of 0.52. Low support indices still indicate insufficient data for many taxa and uncertain status for clades. According to the majority rule consensus, Scutatuspinosus itapagipensis is placed within a "paraclupeine" group with Ezkutuberezi carmenae, Ellimma branneri, Ellimmichthys longicostatus, and Paraclupea chetunguensis. Its minimum age and position among paraclupeids indicate an early history of the group older than it was thought to be, supporting a biogeographical hypothesis based on generalized track from China to northeastern Brazil during the Lower Cretaceous.
Assuntos
Peixes/classificação , Fósseis/anatomia & histologia , Animais , Tamanho Corporal , Osso e Ossos/anatomia & histologia , Brasil , Peixes/anatomia & histologia , Filogenia , FilogeografiaRESUMO
Codoichthys carnavalii is a clupeomorph fish only found in calcareous concretions of Codó Formation, State of Maranhão. It is known based on three specimens housed in the paleontological collection of the Museu de Ciências da Terra of Departamento Nacional da Produção Mineral, Rio de Janeiro. It was omitted in most of recent cladistic analyses about clupeomorphs. We revisited its anatomy furnishing new data and additional restorations. Furthermore we explored the relationships of Codoichthys with the computer program TNT based on a matrix with 30 taxa and 60 unordered and unweight characters. Elops was used to root the tree. The strict consensus was obtained from three shortest trees (L=181; CI=0.387; RI=0.632). The monophyly of Ellimmichthyiformes is supported by a sigmoid cleithrum and an uniquely derived predorsal scute series. Most of subgroups showed low support indices. Sorbinichthyidae and Horseshoeichthys appear in the most basal position, and not closely related to Armigatus or Diplomystus. A Diplomystus clade is more advanced than Armigatus and sister-group of remaining ellimmichthyiforms. Within Paraclupeidae, Codoichthys is sister-group of remaining paraclupeids (including thorectichthyines and paraclupeines). Within Paraclupeinae, Triplomystini includes a Triplomystus clade, a sister group of Rhombichthys plus Tycheroichthys, and Paraclupeini with S. itapagipensis and all other ellimmichthyiform taxa.