Saraiva et al. –First fossil Luciferidae shrimp from the Araripe Basin, Brazil


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Figure 4. Sume marcosi n. gen. n. sp. (LPU 1250A) from the Romualdo Formation, Cretaceous (Albian), Araripe Basin: (1) detail of the anterior region of the carapace showing the antennal flagelum; (2) detail of the carapace including eyes and maxillipeds (black arrow indicates the constriction near the buccal field); (3) detail of somites 1 to 4 of the pleon and pleopods; (4) detail of somites five and six of the pleon, pleopods of the fifth somite, telson and uropods. Scale bars: 1mm. Specimen dry, uncoated. Photos by C. Schweitzer.


town of Trindade, Pernambuco State. The age is Early Creta- ceous (Aptian/Albian).


Description.—Fossil preserved in lateral view. Total length from anterior margin of carapace to the posterior margin of telson 12.20mm; carapace from anterior to posterior margins 3.56mm; abdomen 8.64mm from anterior margin of the first somite to posterior margin of the sixth somite. Carapace length ~3.5 times longer than its maximum height, with a constriction near the buccal field, tapering distally, laterally compressed, with ventral and dorsal margins smooth; posterior margin rounded ventrally. Rostrum not discernible. Antenna and antennule protopodites incompletely preserved, indiscernible, apparently without ornamentation, adjacent to ocular peduncle; with long incompletely preserved flagellum. Eye stalks and eyes apparent, cornea distinct. Second and third maxillipeds discernible, incompletely preserved, segmentation not percep- tible, except for the right third maxilliped with one distin- guishable segment. Pereiopods almost not preserved, except for one-third pereiopod with protopodite and two segments,


very slender, other third and one second pereiopod with proto- podite preserved, without ornamentation. Pleon with six somites, apparently without ornamentation;


pleura overlapping protopods of pleopods, forming a rounded projection medially on somites two to four. First pleonal somite 1.3 times higher than long. Second pleonal somite 1.9 times higher than long. Third pleonal somite length ½ of its maximum height. Fourth pleonal somite length ⅓ of its maximum height. Fifth pleonal somite as long as its maximum height. Sixth pleonal somite elongated, 2.5 times longer than its maximum height, smooth in ventral margin, without ventral processes. Telson small, without visible ornamentation, with acute


distal end. Pleopods well developed, well preserved, first pair longer, slightly decreasing in size to the fifth pair, with long protopodite; exopod or endopod preserved in at least one pleopod of each segment, without visible segmentation and ornamentarion. Petasma not discernible. Uropods incompletely preserved, endo and exopod indiscernible, apparently without ornamentation.


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