Paulo M. Brito

A New Cryptic Species of South American Freshwater Pufferfish of the Genus Colomesus (Tetraodontidae), Based on Both Morphology and DNA Data

The Tetraodontidae are an Acantomorpha fish family with circumglobal distribution composed of 189 species grouped in 19 genera, occurring in seas, estuaries, and rivers between the tropical and temperate regions. Of these, the genus Colomesus is confined to South America, with what have been up to now considered only two species. C. asellus is spread over the entire Amazon, Tocantins-Araguaia drainages, and coastal environments from the Amazon mouth to Venezuela, and is the only freshwater puffers on that continent. C. psittacus is found in coastal marine and brackish water environments from Cuba to the northern coast of South America as far south as to Sergipe in Brazil. In the present contribution we used morphological data along with molecular systematics techniques to investigate the phylogeny and phylogeography of the freshwater pufferfishes of the genus Colomesus. The molecular part is based on a cytochrome C oxidase subunit I dataset constructed from both previously published and newly determined sequences, obtained from specimens collected from three distinct localities in South America. Our results from both molecular and morphological approaches enable us to identify and describe a new Colomesus species from the Tocantins River. We also discuss aspects of the historical biogeography and phylogeography of the South American freshwater pufferfishes, suggesting that it could be more recent than previously expected.

New amiid fish (Halecomorphi: Amiiformes) from the Lower Cretaceous Crato Formation, Araripe Basin, Northeast Brazil

Abstract A new species of Amiidae, †Cratoamia gondwanica gen. et sp. nov., is here described from the Early Cretaceous Crato Formation of the Araripe Basin, northeast Brazil. The new species, based on complete and nearly complete articulated specimens, includes synapomorphies of the subfamily †Vidalamiinae and the tribe †Vidalamiini. The presence of †Cratoamia in Brazil increases the geographical distribution of the tribe †Vidalamiini into the Southern Hemisphere.

A NEW SPECIES OF LEPIDOTES (NEOPTERYGII: SEMIONOTIFORMES: SEMIONOTIDAE) FROM THE SANTANA FORMATION, LOWER CRETACEOUS OF NORTHEASTERN BRAZIL

Abstract A new species of Lepidotes is described on the basis of two nearly complete specimens from the ?Albian Romualdo Member of the Santana Formation, in the Araripe Basin, northeast Brazil. The new species differs from the other species of Lepidotes previously recorded in western Gondwanaland by the apomorphic presence of an axe-shaped hyomandibula, and by a unique combination of other characters. This is the first record of an articulated Lepidotes from the Santana Formation of the Araripe Basin.

A new species of Placidichthys (Halecomorphi: Ionoscopiformes) from the Lower Cretaceous Marizal Formation, northeastern Brazil, with a review of the biogeographical distribution of the Ophiopsidae

Abstract A new halecomorph fish is described from the Early Cretaceous Marizal Formation of Tucano Basin. This new material is identified as a new species of Placidichthys, P. tucanensis sp. nov. based on the absence of an anal fin, the lower number of flank scales in the caudal region, the slender shape of the body, and body proportions. Placidichthys tucanensis sp. nov. increases the distribution and diversity of ophiopsids in the western part of the Tethys Sea, being distributed along the epicontinental seas of Gondwana. Placidichthys is considered the sister-taxon of the exclusively Cretaceous taxa Teoichthys+Macrepistius from the western Tethys. These groups show a discernible geographical distribution pattern with Placidichthys known only from the Southern margin of the Tethys region (South America), whilst Teoichthys and Macrepistius are known only from North America and possibly Europe.

A new Chanidae (Ostariophysii: Gonorynchiformes) from the Cretaceous of Brazil with affinities to Laurasian gonorynchiforms from Spain.

Based on specimens originally referred to as “Dastilbe minor”, a nomem-nudum, we describe a new genus of Chanidae †Nanaichthys longipinnus nov. gen. and sp. which exhibits several diagnostic characters such as the absence of orbitosphenoid and basisphenoid, anteriorly displaced quadrate-mandibular articulation, laterally expanded supraneurals, an acute angle between the preopercular limbs, expansion at the angle between the preopercular limbs, and a curved maxillary articular process. Its occurrence and supposed relationship within the Chanidae reinforce the influence of the Mediterranean Tethys over the Gondwanan main rift system prior to the Aptian/Albian highstands.

Late Cretaceous Belonostomus (Pisces, Actinopterygii, Aspidorhynchidae) from Algarrobo, Chile, with comments on aspidorhynchid paleodistribution in South America

Se describen los restos de un aspidorhinchido recolectado en estratos de la Formacion Quiriquina, Cretacico Superior. Las caracteristicas de tales restos son suficientes para permitir su identificacion como Belonostomus longirostris Lambe. Este es el primer registro confirmado de este genero en Chile. B. longirostris Lambe tuvo un modelo de distribucion marginal en el Pacifico de America del Sur mostrando mas afinidad con la fauna de America del Norte que con la fauna atlantica de America del Sur.

The new genus Potiguara (Actinopterygii: Pycnodontiformes) from the Upper Cretaceous of northeast Brazil

Abstract Pycnodonts are a well-known group of neopterygian fossil fishes with an age range from the Late Triassic to the Eocene. In the present work a new genus, Potiguara, is described to acommodate the species from the Potiguar Basin (northeast Brazil) originally described as Coelodus rosadoi and provisonally placed in the genus Ocloedus. Potiguara clearly belongs to the family Pycnodontidae and can be distinguished from Ocloedus by the absence of spines on the dorsal scales, the number of hypochordal elements in the caudal skeleton, and the number of radials in the dorsal and anal fins. The cladistic analysis supports the exclusion of this species from the genus Ocloedus and consequently the creation of the new genus Potiguara.

The morphology and histology of the scales of Aspidorhynchidae (Actinopterygii, Halecostomi)

Abstract The scales of the three genera of aspidorhynchids (Aspidorhynchus, Belonostomus, and Vinctifer) are studied to bring out some characters useful to understand the systematic position of aspidorhinchids within the neopterygians. The scales of the nine species studied are of lepidosteoid type with a ganoine layer overlaying a basal plate made of lamellar bone with canalicules of Williamson. Some species of Aspidorhynchus are devoid of ganoin, whereas others show only a thin ganoine layer. None of the characters found in the scales of aspidorhynchids can be considered as a familial synapomorphy able to place the clade within the teleosts, a situation that does not imply the exclusion of this family from this major group.

A new halecomorph with two dorsal fins, Placidichthys bidorsalis n. g., n. sp. (Actinopterygii: Halecomorphi) from the Lower Cretaceous of the Araripe Basin, northeast Brazil

Abstract A halecomorph fish is described for the first time from the Lower Cretaceous of the Araripe Basin, northeast Brazil. This new material is identified as a new genus and a new species, Placidichthys bidorsalis. This taxon shares a number of synapomorphies with the Ionoscopiformes, but its position within this clade is still uncertain.

Teoichthys brevipina, sp. nov., A New Ophiopsid Fish (Halecomorphi, Ionoscopiformes) from the Lower Cretaceous Tlayúa Formation, Central Mexico

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