Inoceramid bivalves from the Maastrichtian of the Western Fore-Balkan Mts (Bulgaria)

Abstract

Taxonomic descriptions of newly recorded inoceramid species from the Maastrichtian of the Western Fore-Balkan Mountains (Bulgaria) are presented. The following taxa have been determined: Cataceramus subcircularis (Meek, 1876); Cataceramus palliseri (Douglas, 1942); Cataceramus barabini (Morton, 1834); Cataceramus? glendivensis Walaszczyk, Cobban and Harries, 2001; Cataceramus? cf. bebahoensis (Sornay, 1973); Cataceramus aff. goldfussianus (d’Orbigny, 1847); Trochoceramus tenuiplicatus (Tzankov, 1981); Endocostea typica Whitfield, 1880; Endocostea jolkicevi Walaszczyk, Odin and Dhondt, 2002; Endocostea sp. aff. E. coxi (Reyment, 1955); and “Inoceramus” howletti Walaszczyk, Kennedy and Klinger, 2009. The present record allowed two lower Maastrichtian inoceramid zones, namely the Endocostea typica and Trochoceramus radiosus zones, to be indicated. The material allows for correlation with the Northwestern and Boreal areas of Europe and elsewhere.

Review of the ammonite genus Pseudokossmaticeras Spath, 1922 from the uppermost Campanian–lower Maastrichtian in Bulgaria

“…Tzankov, 1964, p. 146), of which one, identified as "Inoceramus impressus d'Orbigny", is a typical example of Endocostea typica Whitfield, 1880. The latter taxon is the index species for the eponymous inoceramid zone of the lower Maastrichtian (Walaszczyk et al, 2001(Walaszczyk et al, , 2002, which has also been documented in Bulgaria (Dochev et al, 2018;Dochev and Metodiev, 2020;Pavlishina et al, 2020). Thus, P. brandti is again excluded as a record from Kladorub.…”

“…The total chronostratigraphic extent of these units has been determined as upper Campanian (pars. )lower Maastrichtian (e.g., Jolkičev, 1986Jolkičev, , 1989Sinnyovsky and Vangelov, 2007;Dochev, 2012;Dochev and Metodiev, 2020;Pavlishina et al, 2020). From the Darmantsi Formation, the overall record of Pseudokossmaticeras exclusively refers to P. brandti.…”