Sergestidae Dana, 1852

Alencar, Damares Ribeiro, Oliveira, Gustavo Ribeiro De, Pinheiro, Allysson Pontes & Saraiva, Antônio Álamo Feitosa, 2020, New findings on Dendrobranchiata fossils of the Romualdo Formation, Araripe Basin, Northeast of Brazil, Zootaxa 4731 (1), pp. 63-74 : 65-67

publication ID	https://doi.org/ 10.11646/zootaxa.4731.1.4
publication LSID	lsid:zoobank.org:pub:9F2E241B-8161-40B9-B806-F76BAB608A40
persistent identifier	https://treatment.plazi.org/id/03DCF21B-6266-FFF8-15EB-6EEE635085BE
treatment provided by	Plazi
scientific name	Sergestidae Dana, 1852
status

Treatment

Family Sergestidae Dana, 1852 View in CoL

Genus Paleomattea Maisey & Carvalho, 1995

Paleomattea deliciosa Maisey & Carvalho, 1995

( Figure 2 View FIGURE 2 A–B, 3 A–F and 4 A–F)

Holotype: AMNH 44 About AMNH 985.

Type Locality: Romualdo Formation, Santana Group, Chapada do Araripe, Ceará, Brazil.

Stratigraphic Unit: Romualdo Formation, Santana Group, Araripe Basin.

Type Species: Paleomattea deliciosa , by original designation.

Emended Diagnosis: Well-developed ocular peduncles, in terms of height and width equal to one time the total length of the scaphocerite. Reduced and short rostrum reaching to no more than the base of the ocular peduncle and the most distal scaphocerite region, with the rostrum presenting three small rostral teeth; carapace devoid of furrows and keels. Well-developed sixth pleonal somite roughly 3 times longer than it is wide. First three pairs of pereopods well-developed without chelas or pincers, with reduced fourth and fifth.

Description: Small adult shrimps, approximately 10 to 20 mm in total length. Cephalothorax longer than wide, corresponding to roughly 2 times its height ( Fig. 2 A View FIGURE 2 ); Laterally compressed carapace devoid of grooves, keels or tubercules with a sub-triangular shape. Short rostrum ending in three dorsal teeth, not exceeding the ocular peduncle and distal scaphocerite region. Pointed and oblique rostral teeth relative to the midline of the body ( Fig. 3 A View FIGURE 3 ). Hepatic ( Fig. 3 C View FIGURE 3 ) and supraorbital ( Fig. 3 B View FIGURE 3 ) spines present.Absent epigastric, orbital, postorbital, branchiostergal and pterygostomial spines; Slightly convex posterior and ventral cephalothorax margin; Absence of teeth in the ventral region of the cephalothorax; moderately rounded posterior and brachiostegal regions. Longer than broad ocular peduncle, roughly 3 times their width, well-developed relative to the rostrum, without lobes and average sizes of roughly 0. 90 mm to 0.98 mm, ending in lightly pigmented corneas ( Fig. 3 D View FIGURE 3 ).

Moderately preserved corneas, wider than the ocular peduncle, with globular to ovoid shapes. Laminar scaphocerite, roughly a fifth of the length of the ocular peduncle, positioned under the antennular article, slender keel formed in anterior and distal portion, and flattenned dorsoventrally ( Fig. 3 D View FIGURE 3 ). Partially preserved antenna with an antennal flagellum protopod; Segmented antennular flagellum with few visible articles and discernible antennal peduncle ( Fig. 3 D View FIGURE 3 ). Antennule roughly 3 times the ocular peduncle height, broad, and slightly elongated with a present bi-flagellated antenular peduncle, some observable and discernible dorsal and ventral flagella ( Fig. 3 E View FIGURE 3 ). Third maxilliped pair longer and wider than the second pair, with the first pair being undiscernible, unobserved exo- pods and basal spines, the average third maxilliped size is approximately equal to the length of the ocular peduncle without the cornea, with the second pair being 1.5 times smaller than the first pair ( Fig. 3 F View FIGURE 3 ). Smooth, slender pleon roughly 3 times the length of the cephalothorax, smooth pleonal somites without ridges or keels, somites 1 to 5 are as wide as they are long; sixth somite roughly 3 times the length of the first. No pleural overlap, with a slightly rounded base and slight angulation, with slightly planar tergite and slightly concave at its dorsal portion ( Fig. 4 C View FIGURE 4 ). Pereiopods well developed; P1, P2 and P3 without chelipeds, reduced fourth and fifth ( Fig. 4 D View FIGURE 4 ). Pereiopods with present propodus, carpus, merus, however indistinct in the specimens. Missing bristles lacking or protuberances in all appendices. Discernible and well-developed pleopods ( Fig. 4 B View FIGURE 4 ). Telson smaller than uropods, moderately pointed, thornless ( Fig. 4 F View FIGURE 4 ). Partially preserved uropods, slightly larger than telson, equivalent to about half the length of the sixth pleonal somite.

Examined material in mm: LPU 1303 A: Total length: 14.99; Cephalothorax length: 4.28; Pleon length: 10.27; Ocular peduncle length: 0.70 ( Fig.2 A View FIGURE 2 ); LPU 1323: Total length: 12.91; Cephalothorax length: 4.05. ( Fig.3 A View FIGURE 3 ); LPU 1303 A: Total length: 14.99; Cephalothorax length: 4.28; Pleon length: 10.27; Ocular peduncle length: 0.70 ( Fig.3 B View FIGURE 3 ); LPU 1317 Total length: 13.48; Cephalothorax length: 3.87; Ocular peduncle length: 0.50 ( Fig. 3 C View FIGURE 3 ); LPU 1323: Total length: 12.91; Cephalothorax length: 4.05. ( Fig.3 D View FIGURE 3 ); LPU 1268: Total length: 12.47; Cephalothorax length: 4.08; Antennule length: 1.5 Ocular peduncle lenght: 0.84 ( Fig. 2 F View FIGURE 2 ); LPU 1245: Total length: 18.58; Cephalothorax length: 5.18; Ocular peduncle lenght: 0.86. ( Fig. 3 F View FIGURE 3 ). LPU 1363: Total length: 10.63; Pleon length: 7.61; Pleopods: 1.50 ( Fig.4 A View FIGURE 4 ); LPU 1300 B: Total length: 15.87; Pleon length: 12.37; Pleopods: 1.60; Telson total length: 1.81 ( Fig. 4 B View FIGURE 4 ); LPU 1278: Total length: 18.63; Pleon length: 6.81; Pleopods: 1.50 ( Fig.4 A View FIGURE 4 ); LPU 1336: Total length: 19.96; Pleon length: 12.64; Pleopods: 1.10; Telson: 1.30. Uropods: 1.36. Ocular peduncle length: 1.30. ( Fig. 4 D View FIGURE 4 ); LPU 1295 A: Total length: 18.36; Pleon length: 6.60; Pleopods: 1.57; Telson total length: 1.24 ( Fig.4 E View FIGURE 4 ); LPU 1399: Sixth abdominal somite length: 3.01; Telson total length: 1.02 ( Fig.4 F View FIGURE 4 ).

Kingdom	Animalia
Phylum	Arthropoda
Class	Malacostraca
Order	Decapoda
Family	Sergestidae