Microceratina retangularis, Tomé & Araripe & Oliveira & Barreto & Prado & Pedrosa & Pereira & Nascimento & Ng, 2022

Tomé, Maria Emilia, Araripe, Rilda, Oliveira, David, Barreto, Alcina, Prado, Ludmila, Pedrosa, Flavia, Pereira, Priscilla, Nascimento, Luiz Ricardo & Ng, Christiano, 2022, Early Cretaceous Ostracoda (Crustacea) from south-centralAraripe Basin, Brazil with descriptions of seven new species, Zootaxa 5159 (4), pp. 535-557 : 549

Microceratina retangularis sp. nov.

Fig. 5J–L

2022 Microceratina sp. —Araripe et al., p 7, fig. 5 (5a–b).

Etymology: Retangularis (lat.) in reference to the carapace outline.

Holotype: Adult carapace, Nº. DGEO-CTG-UFPE-1525 ( Fig. 5J–L ).

Type locality: Brazil, State of Pernambuco, Municipality of Exu, Santo Antônio section. Coordinates 7° 30’ 06” S and 39° 32’ 36” W .

Type horizon: Santo Antônio section, Araripe Basin. Calcarenite (F-Sl) corresponds to the Romualdo Formation, depth 3.10 m, dated as upper Aptian.

Dimension. Nº. DGEO-CTG-UFPE-1525 ( Fig. 5J–L ); L= (LV) 0.353 / ( RV) 0.335 mm, H= 0.223 mm, and W= 0.191 mm.

Diagnosis: Carapace small and rectangular. It has reticular ornamentation and a ventral posterolateral projection.

Description: Carapace very small. Rectangular outline in the lateral view. Ventral margin rectilinear and parallel. Dorsal margin rectilinear, descends slightly towards the posterior. Anterior margin sub-rectangular. Posterior margin rounded, truncated at ventral margin by small winged process, greater mid-length. Greatest height along the anterior margin. Left valve slightly overlaps right valve in the posterodorsal margin. In the dorsal view, valves are narrow, with the posterior margin subtly wider, ends sharp and short. Surface ornamented with smooth primary reticulations. Winged process at the posteroventral margin.

Observations. Small species, easy to recognize as it presents a rectangular shape. The main difference with the genus Perissocytheridea studied in the present work is the non-occurrence of a caudal process.

Occurrence and associated fauna. It was recorded in the Santo Antonio section, at the following depths (from base to top): 2.65 and 3.4 m. Microceratina retangularis n. sp. does not occur with Alicenula cf. leguminella , Theriosynoecum cf. quadrinodosum and Dicrorygma ( Orthorygma ?) dimorpha.

Stratigraphic distribution. Brazil, Araripe Basin, Romualdo Formation, upper Aptian.

Figures

FIGURE 5. (A–C) Perissocytheridea florisdorsalis sp. nov., nº DGEO-CTG-UFPE-1521, depth 4.05m, (A) right side view, (B) left side view, (C) dorsal view. (D–F) Dicrorygma cf. minuta (Kaye, 1963); (D and E) nº DGEO-CTG-UFPE-1522, depth 3.1m, (D) right side view, (E) left side view; (F) nº DGEO-CTG-UFPE-1523, depth 0.3m, dorsal view. (G–I) Dicrorygma (Orthorygma?) dimorpha Michael Weiss 1996, nº DGEO-CTG-UFPE-1524, depth 5.65m; (G) vista dorsal, (H) right side view, (I) left side view. (J–L) Microceratina retangularis sp. nov., nº DGEO-CTG-UFPE-1525, depth 3.10m; (J) right side view, (K) left side view, (L) dorsal view. (M–O) Alicenula cf. leguminella (Forbes in Lyell 1855), depth 0.3m; (M) dorsal view; (N) left side view; (O) nº DGEO-CTG-UFPE-1526, right side view. (P–R) Theriosynoecum cf. quadrinodosum Krömmelbein & Weber, 1971; nº DGEO-CTG-UFPE-1528, depth 3.1m; (P) dorsal view; (Q) right side view, (R) left side view. The depth reference is from the bottom to the top. Scale bars are equivalent to 100µm.