New Protocytheridae and Mandocytheridae Ostracods from the Aptian of the Crimean Mountains
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ew Protocytheridae and Mandocytheridae Ostracods from the Aptian of the Crimean Mountains M. S. Karpuk* Geological Institute of Russian Academy of Sciences, Moscow, 119017 Russia *e-mail: [email protected] Received August 23, 2019; revised September 26, 2019; accepted September 26, 2019
Abstract—Two new Ostracoda species are described from Aptian sediments of the Crimean Mountains, Protocythere whatleyi Karpuk, sp. nov. (Protocytheridae Lyubimova, 1955) and Homocythere spinasphaerica Karpuk, sp. nov. (Mandocytheridae Gründel, 1969). Keywords: ostracods, Protocytheridae, Mandocytheridae, Aptian, Crimea DOI: 10.1134/S0031030120070059
INTRODUCTION The history of the study of early Cretaceous ostracods of Crimea was described in detail by Karpuk et al. (2019). Crimean ostracods are known for high levels of endemism, and therefore, new species descriptions are required. This paper continues a cycle of publications with such descriptions (Karpuk and Tesakova, 2013; Karpuk and Tesakova, 2014; Karpuk, 2016; Karpuk et al., 2019). Two new species of late Aptian ostracods from the Crimean Mountains are described in this paper. Ostracods of these species were collected from six sections, Verkhorechie, Krasnaya Gorka, Kirpichnoe, Maryino, Kurskoe, and Zavodskaya Balka. The age of the sections was determined using ostracods, planktonic foraminifera and calcareous nannofossils (Karpuk, 2016; Brovina, 2017; Brovina et al., 2017; Karpuk et al., 2018). The new species Protocythere whatleyi Karpuk, sp. nov. (family Protocytheridae Lyubimova, 1955) and Homocythere spinasphaerica Karpuk, sp. nov. (family Mandocytheridae Gründel, 1969), are similar in having a triplicate carapace of triangularovate shape, and three large longitudinal ribs. A triplicate carapace is a feature of several species, of varying systematic position depending on which feature is considered to be the most important—hinge or carapace shape. If the hinge is treated as the main feature (Nikolaeva, 1999), then the genera Protocythere, Costacythere Gründel, 1966, Hehticythere Gründel, 1974, Reticythere Gründel, 1978, Pseudoprotocythere Oertli, 1966, and Valendocythere Gründel, 1969 will be combined in one family, Protocytheridae Lyubimova, 1955, as all of them have an antimerodont hinge crenulated in marginal parts. They differ in carapace shape: rectangular-ovate (e.g. Costa-
cythere, Hehticythere, Reticythere) or triangular-ovate (e.g. Protocythere), with a differing longitudinal rib joint. Species with similar carapace shape (Protocythere, Posteroprotocythere Mandelstam, 1958, Homocythere Kaye, 1963, Cytherettinella Andreev and Mandelstam, 1964, and Veenia Butler and Jones, 1957) are placed in different families, and the similarity may be explained as convergence in different phyletic lines. If the carapace shape and the ribs joints are considered to be more important than the hinge, following Mandelstam (Andreev and Mandelstam, 1964), the following phyletic lineage may be considered: from Protocythere with a merodont type hinge in the Late Jurassic-Early C
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