Loxoconchissa reticulata var. rugosa, Rausch & Stoica, 2019

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 : 61-5

Loxoconchissa (Loxocaspia) aff. reticulata Faranda, Gliozzi and Ligios , var. rugosa n. subsp.

Description. The carapace with a rhomboidal shape in lateral view is covered in a coarse to fine reticulation pattern, that consists of a greater part of longitudinally elongated meshes that become less pronounced towards the posterior end and finer in the anterior part. The degree of the ornamentation varies and, in some specimens, occurs notably coarser, also including larger pore-conuli. The species shows remarkable sexual dimorphism. The male carapace is more elongated and the most prominent feature is the presence of a single large-size tubercle in the posterior-central part of the valve that is especially impressive from the dorsal view. The tubercle appears to be more pronounced in comparison to the Loxoconchissa (Loxocaspia) aff. reticulata one and in some cases is covered by the above-mentioned reticulation pattern. A distinguishable eye-spot is present at the anterodorsal corner. The dorsal margin is straight and is smoothly and broadly rounding onto the anterior and posterior ends. The ventral margin runs parallel to the dorsal one and is slightly depressed around mid-valve. The preservation of this species in most cases is poor and a layer of secondary calcite has been observed regularly. Dimension: Male: l = 0, 57- 0, 59 mm, h = 0, 30- 0, 33 mm; Female: l = 0, 52 – 0, 54 mm, h = 0, 30 – 0, 32 mm b = 0, 16 mm.

Ecology. The ecological preference of L. rugosa is unknown but the genus is generally known to inhabit mainly brackish and shallow marine environments ( Moore, 1961; Van Morkhoven, 1962). The variability regarding the ornamentation is thought to be of genetic origin rather than environmentally driven, since the variation can be observed within a single sample. We therefore assume the presence of a strongly ornated morphotype, that can be related to the alkalinity of the lake.