Araripe Basin DUPLICATE - REPLACE (Cretaceous of Brazil)

Where: Ceará, Brazil (7.2° S, 40.0° W: paleocoordinates 7.9° S, 7.8° W)

• coordinate based on nearby landmark

• basin-level geographic resolution

When: Nova Olinda Member (Crato Formation), Aptian (125.0 - 113.0 Ma)

• Nova Olinda Member of the Crato Formation, Araripe Basin, a fossil Lagerstatte famous for the exceptional preservation of diverse Early Cretaceous (Aptian) biota

Environment/lithology: terrestrial; lithified limestone

• The Crato Formation comprises a diverse suite of sedimentary rocks including oil shales, variegated clays, sandstones and limestones (Martill 1988, 1993). Some marginal environments include quartzite pebble conglomerates and brecciated laminites. The Crato Formation rests conformably on a variety of

•sedimentary rocks due to previous environmental diversity prior to the development of the Crato lagoon (Martill and Wilby 1993). Salinity levels fluctuated, but were probably elevated during deposition of the Nova Olinda Member.

•The Nova Olinda Member comprises a 6–8m thick sequence of laminated limestones, pisolites and occasionally stromatolites. This basal member of the Crato Formation is mined in the region of Nova Olinda-Santana do Cariri and Tatajuba, and also at Crato. Most of the fossils are obtained by the miners and sold to local dealers.

•The majority of this unit is made up of millimetrically laminated limestones with shale partings in the basal metre.

Size class: macrofossils

• One specimen of Axelrodichthys measuring 70mm in total length

Collection methods: Specimens kept at Universidade Regional do Cariri in Ceara State, Brazil (reference 45772)and University Museum of Zoology, Cambridge, England (UMZC) (reference 45533).

•Reference:45533 - Specimens were examined by light microscopy and scanning electron microscopy. Some fossils required matrix removal before examination to reveal diagnostic features. This was achieved by usingmounted entomological needles in concert with a fine paint brush to remove thin layers of limestone. In addition, two were coated on one side with polyvinyl butyrol, and the matrix removed by immersion in 10 per cent. acetic acid to reveal the unweathered side. Specimens were then examined using a Wild microscope with attached Zeiss Camera lucida drawing arm.

Primary reference: P. M. Brito and D. M. Martill. 1999. Discovery of a juvenile coelacanth in the Lower Cretaceous, Crato Formation, Northeastern Brazil. Cybium 23(3):311-314 [M. Bell/M. Bell]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 140951: authorized by Mark Bell, entered by Mark Bell on 19.03.2013

Creative Commons license: CC BY (attribution)

Taxonomic list