Cyprideis amazonica 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 : 13-16

publication ID	https://doi.org/ 10.11646/zootaxa.3899.1.1
publication LSID	lsid:zoobank.org:pub:D78F2010-08E1-45C0-86FF-7F2D3601070D
persistent identifier	https://treatment.plazi.org/id/017587FE-FFA0-FFC8-71F4-DED6FD4AFD7A
treatment provided by	Felipe
scientific name	Cyprideis amazonica Purper, 1979
status

Treatment

Cyprideis amazonica Purper, 1979 View in CoL

Figs. 4a–c View FIGURE 4 ; Pl. 1, Figs. 1 View FIGURE 1 –26

1977 Cyprideis sp. nov. B—Purper: 363; Pl. 3, Figs. 11–16.

* 1979 Cyprideis amazonica Purper , sp. nov. —Purper: 231–232; Pl. 4, Figs. 1 View FIGURE 1 –11.

1998 Cyprideis amazonica Purper, 1979 View in CoL —Muñoz-Torres et al.: 94; Pl. 2, Figs. 4–6 View FIGURE 4 View FIGURE 5 View FIGURE 6 .

1998 Cyprideis amazonica Purper, 1979 View in CoL —Whatley et al.: 234; Text-fig. 2; Pl. 1, Figs. 1–5 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 .

non 1998 Cyprideis amazonica Purper View in CoL —Swain: 3; Pl. 2, Fig. 7 View FIGURE 7 .

2010 Cyprideis amazonica Purper, 1979 View in CoL —Wesselingh & Ramos: 308, 315; Figs. 18.5k–l.

2011 Cyprideis amazonica View in CoL —Linhares et al.: 95, 98; Figs. 3 View FIGURE 3 /1–2.

Material. 1,083 valves; samples AM 10/4, 6, 7, 39, 40 (in AM 10/6 and 7 about four times more material available but not counted).

Dimensions (total range over all samples). R ♀ l = 0.72–0.90 (0.82), h = 0.40–0.47 (0.44; n = 14); L ♀ l = 0.76–0.89 (0.83), h = 0.44–0.51 (0.47; n = 13); R ♂ l = 0.85–0.96 (0.91), h = 0.43–0.47 (0.45; n = 8); L ♂ l = 0.84–0.96 (0.91), h = 0.46–0.50 (0.48; n = 7); Rj(A-1) l = 0.59–0.69 (0.65), h = 0.35–0.38 (0.37; n = 11); Lj(A-1) l = 0.56–0.70 (0.65), h = 0.35–0.40 (0.38; n = 9); Lj(A-2) l = 0.53, h = 0.33 (n = 1) .

Remarks. C. amazonica is an asulcate species with a smooth surface except well-spaced, roundish puncta, which correspond to normal pore canal openings. Right valves have a “well developed posterior rim” (Muñoz- Torres et al. 1998: 234 = “postero-lateral concavity” in Purper 1979: 232). Both valves develop a narrow anterior vestibulum ( Figs. 4a–c View FIGURE 4 ). Marginal pore canals are simple or—more frequently—bifurcating.

C. amazonica occurs in core 1AS-10-AM only in the lower (AM10/40–39) and in the upper part (AM10/7–6, 4). Especially, AM10/39 and 10/7 contained rich material, about 147 m apart from each other.

The material from samples AM10/7–6 matches well with the given synonyms (Pl. 1, Figs. 1–8 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 6 View FIGURE 7 View FIGURE 8 ). Valves from sample AM10/40–39 are slightly smaller, somewhat more roundish in outline and the extension of the flange at the lower half of the posterior margin is reduced (Pl. 1, Figs. 9 View FIGURE 9 –16). Here, we consider these differences as intraspecific variation of C. amazonica .

C. amazonica figured by Swain (1998) diverges considerably in outline and clearly belongs to another Cyprideis species.

In addition to the descriptions of Purper (1979), Muñoz-Torres et al. (1998) and Whatley et al. (1998), we observed in well-preserved right valves some (up to six) short posteroventral denticles (Pl. 1, Fig. 25b). Interestingly, in larvae—which have never been described or figured so far—these posteroventral denticles are more clearly visible (Pl. 1, Fig. 26b) and become almost fused with the flange in the adult stadium.

Moreover, juvenile valves from AM10/39 exhibit numerous anteroventral denticles (Pl. 1, Fig. 26a), which are incorporated in the selvage–flange zone in adult valves where only traces in form of marginal ripplets are left over (Pl. 1, Fig. 25a). Anteroventral marginal spines are missing in juvenile valves from the upper part of the core (Pl. 1, Fig. 20). Very faint crenulations of the flange could be a reminiscence of them, observable in some valves of AM10/7.

At first glance, the anteroventral denticles resemble the dentate margin of juveniles of Cyprideis caraionae Purper & Pinto, 1985 , which is in its adult stage similar in outline and ornament to C. amazonica ( Whatley et al. 1998) . However, larvae of C. caraionae from topotypic material (1AS-33-AM; sample depth 290.1 m) display another kind of anterior denticle development. They have fewer, longer and more widely spaced denticles, in which further in-between denticles develop in the adult stadium in order to become the characteristic downward-turned, coalescent spines of C. caraionae (pers. observ., M.G.). Further investigations are obviously needed. Here, we just want to highlight the importance of the study of the ontogeny that may help determine relationships among different taxa.

Occurrence. Western Amazonia ( Brazil, Colombia, Peru), early Middle to early Late Miocene ( C. aulakos – C. cyrtoma zone; Muñoz-Torres et al. 2006; chronostratigraphic correlation after Wesselingh & Ramos 2010).

4.5.2. machadoi subgroup

Species. C. machadoi and C. kotzianae ; possibly C. truncata but re-examination pending.

Characters. Elongated-subtrapezoidal, with or without anterior “ Chlamydotheca ”-like extension; medium to large sized; smooth, asulcate; no marginal spines (in adults); very wide inner lamella with well-developed anterior vestibulum; anterior simple, bi- or polyfurcated marginal pore canals; hinge with moderately long antero- and long posteromedian element, sometimes inverse.