Darwinula stevensoni ( Brady & Robertson, 1870 )

Rausch, Lea & Stoica, Marius, 2019, AN EARLY PLEISTOCENE ANOMALOHALINE WATER OSTRACOD FAUNA FROM LAKE DEPOSITS OF THE HOMO ERECTUS-BEARING KOCABAŞ LOCALITY (SW TURKEY), Acta Palaeontologica Romaniae 15 (2), pp. 41-69 : 2

Darwinula stevensoni ( Brady & Robertson, 1870)

1870 Policheles steven- - Brady & Robertson,

soni nov. sp. p. 25, pl. 7, figs. 1-7,

pl. 10, figs. 4-14.

1962 Darwinula ste- - Morkhoven, p. 29-

vensoni (Brady & 31, figs. 35-38.

Robertson)

1995 Darwinula ste- - Olteanu, pl.VIII; fig. vensoni (Brady & 10.

Robertson)

2000 Darwinula ste- - Meisch, p. 49, figs.

vensoni (Brady & 16 A-E.

Robertson)

2012 Darwinula ste- - Fuhrmmann, p. 14, vensoni (Brady & pl. 1, figs. 1 a-f.

Robertson)

2015 Darwinula ste- Van Baak, fig. 7, 16- vensoni (Brady & 19.

Robertson)

Description. The carapace is elongated and subcylindrical in shape. From the side view both edges are rounded, whereas the RV overlaps the LV. The dorsal margin is slightly arched, whereas the ventral margin possesses a very slight concavity. The transition onto the anterior-and posterior end is smooth. The posterior is somewhat sharply rounded, unlike the anterior that appears more bluntly-rounded. The ornamentation is smooth and the carapace in general appears to be very thin and fragile. The muscle scar is typical for the genus, arranged in form of a rosette and the hinge is adont. Dimension: l = 0,59 – 0,64 mm, h = 0,24 – 0,28 mm, b = 0,22 mm.

Ecology. The cosmopolitan Darwinula stevensoni lives mostly in freshwater environments and has been described from recent oligohaline waters of SW Florida. Less common are occurrences in mesohaline environments with salinities up to 15 g /l ( Van Morkhoven, 1962; Keyser, 1977; Martens et al., 1997). Living representatives are usually to be found in littoral environments, for example along the Paraná river in southern Brazil ( Higuti et al., 2009). The species is also inhabiting ponds, lakes and low energy streams. In the fossil record it has been described from Late Holocene sediments of the Black Sea ( Briceag et al., 2012).