Priorhyncha feitosai, Alencar & Pinheiro & Saraiva & Oliveira & Santana, 2018

Alencar, Damares Ribeiro, Pinheiro, Allysson Pontes, Saraiva, Antônio Álamo Feitosa, Oliveira, Gustavo Ribeiro De & Santana, William, 2018, A new genus and species of Solenoceridae (Crustacea, Decapoda, Dendrobranchiata) from the Cretaceous (Aptian / Albian) of the Araripe Sedimentary Basin, Brazil, Zootaxa 4527 (4), pp. 494-500 : 496-498

Priorhyncha feitosai n. gen. n. sp.

( Figure 3 A–E)

Holotype: MPSC 2 489.

Diagnosis: Same as for the genus.

Occurrence: The sole specimen was collected in the town of Trindade, Pernambuco State; Romualdo Formation, Santana Group of the Araripe Sedimentary basin, age Early Cretaceous (Aptian/Albian).

Description: Fossil in lateral view. Total length from tip of rostrum to posterior margin of telson 13.5 mm, carapace length including rostrum 5.2 mm. Carapace laterally compressed, ventral margin smooth; dorsal margin of carapace almost straight, posterior margin rounded ventrally, margins without spines; antennal spine present, other spines not discernible. Cervical groove of carapace well-marked, otherwise smooth. Rostrum short, robust, slightly longer then eye, dentate, with 10 short spines dorsally, ventral margin smooth; rostrum slightly arched downward. Eyestalk short, eye preserved almost reaching tip of rostrum. Antennal protopodite preserved, scaphocerite faintly preserved, apparently longer than eye; antennular peduncle preserved, longer than scaphocerite. Third maxillipeds not preserved. Pereiopods scarcely preserved, with few delicate meri discernible. Pleon with six somites, all apparently without ornamentation, pleura well developed, ventrally rounded on first to fifth somites; first to third and fifth somites of about same size, fourth slightly longer, sixth somite strong, 1.5 times as long as second. Telson only preserved proximally, missing distal end. Pleopods of first to third somites poorly preserved, other pleopods and uropods not preserved.

Etymology: The specific epithet is an homage to the priest Neri Feitosa, who was one of the first to study and collect fossils in the Araripe Basin a long time ago.

Remarks: The shape of the rostrum, with 10 dorsal spines, and the marked cervical groove can easily separate Priorhyncha feitosai n. gen. n. sp. from the other fossil species known to occur in the Araripe Sedimentary basin (i.e., Beurlenia araripensis Martins-Neto & Mezzalira, 1991 ; Kellnerius jamacaruensis Santana, Pinheiro, Silva & Saraiva, 2013 ; Paleomattea deliciosa Maisey & Carvalho, 1995 ; and Sume marcosi Saraiva, Pinheiro & Santana, 2018). Also, when compared to Araripenaeus timidus Pinheiro, Saraiva & Santana, 2014 , of which a full carapace is unknown, Priorhyncha feitosai n. gen n. sp. has a smooth sixth pleonal somite (with a distinct sinuous carina in A. timidus ).

The presence of several shrimp species in the Romualdo Formation reinforces the marine characteristics of the environment and may be indicative of mortality events associated with strong marine incursions, such as tsunamis, that brought this species to the paleolagoon Araripe, and initiating the fossilization process.

Figures

FIGURE 3. Prioryncha feitosai n. gen. n. sp. (MPSC 2489). A, Lateral view of the holotype. B, Scanning Electron Microscopy (SEM) of the anterior region of the cephalothorax. White arrow indicates the cervical groove; black arrow the antennal spine; and red arrow the dorsal serration of the rostrum. Scale bars 1 mm. Specimen dry, uncoated. Photos by W. Santana and A. Pinheiro.