Distributional patterns of Aptian-Albian paleoichthyofauna of Brazil and Africa based on Track Analysis.

The Aptian-Albian paleoichthyofauna in Brazil and Africa is quite diverse, yet their geographic patterns still require accounts. This work consists of a panbiogeographical analysis of paleoichthyofauna from Aptian-Albian through track analysis. Geographic coordinates were obtained and converted into paleocoordinates. Individual Tracks (ITs) and Generalized Tracks (GTs) were built with the aid of ArcView GIS v3.2 program using Trazos2004 extension. As a result, four GTs and tree Biogeographic Nodes (A, B and C) had been identified. GTs 1 and 2 shows two different faunas. GT3 indicates similarity between Brazil and Africa paleoichthyofauna suggesting the break-up of Gondwana as the event that separated it. GT4 represents a probable local seaway produced by transgressions. In the Node A a unique fauna was found indicating the presence of a third biota with its own characteristics. Node B is associated with the break-up of the supercontinent Gondwana. Node C was related to fauna exchange promoted by marine ingression and epicontinental seas that occurred during Aptian-Albian. We concluded that there is a relationship between the distributional patterns of biota and events such as the break-up of Gondwana, the formation of Atlantic Ocean and eustatic movements that affected South America and Africa.

Reassessment and Relationships of Scutatuspinosus itapagipensis (Teleostei, Clupeomorpha, Ellimmichthyiformes) from the Neocomian of Recôncavo Basin, Northeastern Brazil

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.

Reassessment and Relationships of †Scutatuspinosus itapagipensis (Teleostei, Clupeomorpha, †Ellimmichthyiformes) from the Neocomian of Recôncavo Basin, Northeastern Brazil.

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.

Relationships of †Codoichthys carnavalii Santos, 1994 (Teleostei, Clupeomorpha, †Ellimmichthyiformes) from the Late Aptian of São Luís-Grajaú Basin, NE Brazil.

†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.