Saraiva et al. –First fossil Luciferidae shrimp from the Araripe Basin, Brazil
the formation, we found marl intervals with ichthyoliths and carbonate concretions preserving three-dimensional fossils and common fishes, as well as fossil imprints among the blade-like shale fragments and marls (Saraiva et al., 2007). Above the gypsum pack of the Ipubi Formation is an erosional disconformity, which is considered the boundary between Ipubi and Romualdo formations (Neumann et al., 2003). A sequence
of shale with fossil impressions, mainly shrimps and some fishes, begins just above this disconformity. Unlike the three- dimensional shrimp fossils found in carbonate concretions, which do not preserve the ends of the body, impressions occurring in the shale are generally complete. The shrimp impressions in this level can be found throughout the southern part of the Araripe Basin in a layer ~80cm thick. About 30m above this facies, the shrimps Paleomattea deliciosa, Kellnerius jamacaruensis Santana et al., 2013, and Araripenaeus timidus Pinheiro, Saraiva, and Santana, 2014, and the crab Araripecarcinus ferreirai Martins-Neto, 1987, have been found. At the same level, the fossil imprint of Sume marcosi n. gen. n. sp. was found in calcareous shales with several specimens of Araripenaeus timidus and Paleomattea deliciosa in carbonate concretions of the Romualdo Formation (Fig. 1).
Materials and methods
The material studied here was collected in a mining site (Mineradora Serra Suposta), municipality of Trindade, Per- nambuco State, 07°43'37.4''S, 040°32'26.8''W (Fig. 2). Descriptions, drawings, and photographs were made using a stereomicroscope Nikon SMZ 745T equipped with camera lucida and a Leica EZ4 W, both with digital camera attached. The software ISCapture 3.6.1 was used to take the measure- ments, all in millimeters (mm). The specimen of Belzebub faxoni (Borradaile, 1915) used in the comparisons was stained with rose Bengal (Fig. 3).
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Repository and institutional abbreviation.—The holotype material studied, described, and illustrated here is deposited in the Laboratório de Paleontologia da Universidade Regional do Cariri (LPU).
Systematic paleontology Order Decapoda Latreille, 1802
Suborder Dendrobranchiata Bate, 1888 Superfamily Sergestoidea Dana, 1852 Family Luciferidae De Haan, 1849
Genus Sume new genus Type species.—Sume marcosi n. gen. n. sp.
Diagnosis.—Eyestalks of moderate length, not reaching the end of scaphocerite; pleonal pleura overlapping protopods of pleopods, forming a rounded projection medially on somites two to four.
Etymology.—Sumé, from the Tupi mythology, is a god that disappeared in the Atlantic Ocean. Gender masculine.
Remarks.—Sume n. gen. presents several diagnostic characters of Luciferidae, including a carapace laterally compressed and anteriorly elongate, with the buccal frame widely separated fromantennae and eyes; reduced thoracic appendages; and fourth and fifth pereopods absent. Among the Luciferidae, Sume n. gen. resembles Belzebub in its moderately long eyestalks that do not reach the end of the scaphocerites, while Lucifer has elongated eyestalks. Sume n. gen. can be differentiated from Belzebub based on the pleonal pleura overlapping the protopods of the pleopods, forming a rounded pro- jection medially on somites two to four (pleonal pleura do not overlap the protopods of the pleopods, nor do they form a rounded projection medially on somites two to four in Belzebub).
Figure 2. Geographic position of the sampling site Trindade in the Araripe Basin, northeast Brazil. Colors indicate the different sequences of the Araripe Basin.
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