Perissocytheridea florisdorsalis, 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 : 547-548

Perissocytheridea florisdorsalis sp. nov.

Fig. 5A–C

2022 Perissocytheridea sp.3 —Araripe et al., p 7, fig. 4 (3a–b).

Etymology: Floris (lat.) due to the design of a flower in the ornamentation of the carapace and dorsalis (lat.) marks the region and view in which the said design is observed.

Holotype: Adult C, Nº. DGEO-CTG-UFPE-1521 ( Fig. 5A–C ).

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

Type horizon: Santo Antônio section, Araripe Basin. Shale (F1) corresponding to Romualdo Formation, depth 4.05 m, dated as upper Aptian.

Dimension. Nº. DGEO-CTG-UFPE-1521 ( Fig. 5A–C ); L= (LV) 0.373 / ( RV) 0.356 mm, H= 0.189 mm, and W= 0.171 mm.

Diagnosis: Carapace very small, reticulated surface and a subtle caudal process at the dorsal margin. Additionally with a flower design in the dorsal view.

Description: Carapace very small. Sub-rectangular outline in lateral view. Ventral margin rectilinear on both valves. Dorsal margin straight descends to the posterior end. Anterior margin sub-rounded, beginning dorsally rectilinear and rounding up to ventral margin. Posterior margin sub-rectangular tapering to the caudal processes, which coincides with greatest length. Greatest height at anterior margin. Left valve slightly overlaps right valve. In the dorsal view the caudal process is evident, giving the posterior end a sharp appearance. Anterior margin also presents a sharp appearance. Surface with primary reticulations. Winged process discrete in the postero-ventral margin. Presents a lateral sulcus, where a flower-like design is seen in the dorsal view. Discrete ocular tubercle blending with ornamentation.

Observations. This species differs from others species to the genus described in this paper by the presence of a flower-shaped ornamentation in the dorsal view. However, a further detailed study with a larger population is needed to differentiate the male and others ontogenetic stages.

Occurrence and associated fauna. It was recorded in the Santo Antônio section, at the following depths (from base to top): 0.3; 2.25; 2.65; 3.1; 4.05; 3.55 and 5.45 m. Perissocytheridea florisdorsalis sp. nov. does not occur with 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.