Cyprideis reticulopunctata ( Purper, 1979 )

Gross, Martin, Ramos, Maria Ines F. & Piller, Werner E., 2014, On the Miocene Cyprideis species flock (Ostracoda; Crustacea) of Western Amazonia (Solimões Formation): Refining taxonomy on species level, Zootaxa 3899 (1), pp. 1-69 : 26

Cyprideis reticulopunctata ( Purper, 1979)

Pl. 7, Figs. 21–31

1977 Cytheridea sp.nov. B—Purper: 361; Pl. 2, Figs. 7 –13.

* 1979 Cytheridea reticulopunctata Purper , sp. nov. —Purper: 227–228; Pl. 2, Figs. 1–10 .

Material. 101 valves; sample AM 10/3.

Dimensions (total range over all samples). R ♀ l = 0.87–0.93 (0.89), h = 0.48–0.52 (0.49; n = 5); L ♀ l = 0.89–0.93 (0.91), h = 0.49–0.54 (0.52; n = 4); R ♂ l = 0.96–1.00 (0.99), h = 0.51–0.53 (0.52; n = 3); L ♂ l = 0.95–1.06 (1.00), h = 0.48–0.56 (0.52; n = 5);?Lj(A-1) l = 0.70–0.79 (0.75), h = 0.38–0.49 (0.44; n = 2).

Remarks. This subovate–subrectangular species is characterised by its ornamentation with a low, internally punctated reticulum (“compose puncture forming broad reticulum”; Purper 1979: 227). Along the entire anterior margin, little marginal spines are developed. One prominent posteroventral spine is developed in right and left valves. Right valves carry 3–4 additional denticles above this main spine ( Purper 1979).

The current specimens perfectly coincide with the description of Purper (1979), which, however, remains the only evidence of that species up to now. In core 1AS-10-AM, it occurs only in the uppermost productive sample (AM10/3). Here we apply the generic concept of Whatley et al. (1998) and transfer this species to the genus Cyprideis .

C. reticulopunctata is extremely similar to the slightly smaller C. graciosa , which has a pitted ornament with the tendency to become reduced anteroventrally and anterocentrally. C. aff. graciosa (material herein, see above) additionally lacks posteroventral spines in left valves and has more prominent anteromarginal spines.

C. longispina is very close to C. reticulopunctata but the former is more elongated, typically with a very extended flange posteroventrally (right valves), and with an overall finer (punctate) ornament. Anterior spines are restricted to the lower half of the anterior margin and posteroventral spines are never developed in left valves ( Purper 1979; Muñoz-Torres et al. 1998; Gross et al. 2013).

Occurrence. Western Amazonia ( Brazil), latest Middle to early Late Miocene ( C. obliquosulcata – C. cyrtoma zone; this study; chronostratigraphic correlation after Wesselingh & Ramos 2010). Up to now only known from core CPCAN-III-São Paulo de Olivença (depth: 31.52–32.62 m, altitude: ~ 21 m; Purper 1979).

Figures

FIGURE 1. Location of the study area in western Amazonia. a: Isopatches [m] of the thickness of the Solimões Formation in the Acre and Solimões Basins (after Maia et al. 1977; Latrubesse et al. 2010); b: Coal-prospection area with isopatches [m] of the Solimões Fm. and position of exploration wells (after Maia et al. 1977; star = herein investigated core 1AS-10-AM; additional boreholes marked with numbers are mentioned in this study; location of CPCAN-I–III after Nuttall 1990).

FIGURE 2. Section of well 1AS-10-AM (γ-log, lithology, samples, macrofossil content and core intervals; based on unpublished CPRM report and own observations).

FIGURE 3. Western Amazonian Cyprideis species groups. a: Phylogenetic model of Muñoz-Torres et al. (2006; Whatley et al. 1998); chronology and phylogenetic relations (stippled lines) redrawn form Muñoz-Torres et al. (2006); taxonomic rearrangements in group allocations in grey (C = Cyprideis, s. MT = sensu Muñoz-Torres et al. (1998), syn. = synonymous); b: herein proposed grouping, based exclusively on morphologic similarities (species without photographs = revision pending).

FIGURE 4. “Smooth” Cyprideis species of core 1AS-10-AM (except Figs. j–k = core 1AS-32-AM) photographed in transmitted light (external view) and focus stacked (scale bar = 200 µm; L/R = left/right valve; ♀/♂ = female/male; l/h = length/height [mm], specimen code = sample number_specimen number). a–c: C. amazonica, a: L♂ (0.84/0.46; AM10-39_44), b: R♀ (0.85/0.46; AM10-7_94), c: R♀ (0.74/0.42; AM10-39_42); d–f: C. machadoi, d: L♀ (1.09/0.58; AM10-23_66), e: L♀ (1.06/0.53; AM10-27_74), f: R♂ (1.08/0.51; AM10-27_73); g–k: C. kotzianae, g: R♂ (0.83/0.38; AM10-27_75), h: L♀ (1.00/ 0.46; AM10-30_36), i: R♂? (0.95/0.43; AM10-30_117), j: L♀ (0.87/0.41; AM32-5_26), k: R♀ (0.86/0.40; AM32-5_39); l–m: C. olivencai, l: L♀ (0.73/0.38; AM10-7_97), m: R♀ (0.75/0.38; AM10-7_96); n: C. kroemmelbeini, L♀ (0.83/0.41; AM10- 7_100); o: C. paralela, R♀ (0.61/0.30; AM10-30_100); p–r: C. multiradiata, p: L♀ (0.78/0.37; AM10-30_116), q: L♂ (0.89/ 0.38; AM10-30_114), r: R♂ (0.89/0.37; AM10-30_113).

FIGURE 5. Variation in length of right female valves (Rf) in core 1AS-10-AM of some more frequent Cyprideis species (min = minimum, max = maximum, max range/sa = maximum range within one sample; aside the box plots the number of measured specimens per sample is indicated).

FIGURE 6. “Ornate” Cyprideis species of core 1AS-10-AM photographed in transmitted light (external view) and focus stacked (scale bar = 200 µm; for abbreviations, see Fig. 4). a–b: C. cyrtoma, a: R♀ (0.73/0.37; AM10-27_15), b: R♀ (0.79/ 0.41; AM10-30_51); c: C. schedogymnos, R♀ (0.77/0.39; AM10-42_20); d: C. aff. graciosa, R♂ (0.95/0.48; AM10-30_68); e: C. minipunctata, R♀ (0.80/0.44; AM10-42_26); f: C. curucae, R♀ (0.80/0.42; AM10-23_06); g: C. pebasae, L♀ (0.67/0.36; AM10-27_79); h–i: C. munoztorresi, h: L♀ (0.74/0.39; AM10-15_23), i: R♀ (0.75/0.38; AM10-15_25); j–k: C. ituiae, j: L♀ (0.64/0.33; AM10-23_105), k: R♀ (0.68/0.35; AM10-30_118); l–m: C. matorae, l: L♀ (0.80/0.43; AM10-30_121), m: R♂ (0.81/0.39; AM10-30_120); n: C. inversa, L♂ (0.58/0.32; AM10-30_122); o: C. sulcosigmoidalis, R♀ (1.01/0.59; AM10- 7_47).

FIGURE 7. Variation of some traits in C. sulcosigmoidalis (for ornamentation and selvage position specimens were assigned to classes (1–3; ESM 2); if more than one class occur in one sample, the arithmetic mean is also displayed; the number of studied specimens per sample is indicated next to the bars; min = minimum, max = maximum, max range/sa = maximum range within one sample, Rf = right female valves).

FIGURE 8. Ostracod based biozonation of Muñoz-Torres et al. (2006) and remarks (correlations of biozones and chronostratigraphy after Wesselingh et al. 2006b; Wesselingh & Ramos 2010; FAD = first appearance datum and LAD = last appearance datum sensu Muñoz-Torres et al. (2006); s. MT = sensu Muñoz-Torres et al. (1998), s. P = sensu Purper (1979), syn. = synonymous).

FIGURE 9. Stratigraphic range of herein treated Cyprideis species mainly based on Muñoz-Torres et al. (2006; for details see chapters 4.5. and 4.6.; correlations of biozones and chronostratigraphy after Wesselingh et al. 2006b; Wesselingh & Ramos 2010; arrows: probably further extending into the Late Miocene, see Gross et al. 2013).

FIGURE 10. Distribution of Cyprideis species in core 1AS-10-AM and ostracod biozonation (barren samples AM10/45–47 as well as the single valve in AM10/48 not displayed; asterisk at samples AM10/6–7: more (~four times) material available but not counted; for legend of the lithology, see Fig. 1).