Some stratigraphically im­por­tant Larger Benthic Foraminifera from the Lower Jurassic and Sievoides blumenthali sp. nov., Beyaz Aladag Unit, Eastern Taurides, S Türkiye

Abstract

The Lower Jurassic suc­ces­sion in the Beyaz Aladağ Unit (Eastern Taurides) in­cludes Het­tan­gian-Pliensbachian shal­low-ma­rine carbonates. The stud­ied Sinemurian-Pliensbachian stra­ta, char­ac­ter­ized by abun­dant oncoids and mega­lo­dontid bivalve shells, con­tain a di­ver­si­fied benthic forami­niferal assemblage in­clud­ing orbitopsellids, hauraniids, biokovinids, cyclamminids, and sipho­val­vu­linids taxa. This paper focuses on the morphological analysis of the key biostratigraphic mark­er species Lituo­­septa recoarensis Cati, 1959, Lituolipora termieri (Hottinger, 1967), Bosniella oenensis Gušić, 1977, and in­tro­duces a new Larger Benthic Foraminifera, Sievoides blumenthali sp. nov. Some poor­ly known morphological char­ac­ter­is­tics of these index species have been il­lus­trat­ed, and some po­ten­tial discrepancies have been im­proved. The se­lect­ed taxa have been documented here for the first time from the Beyaz Aladağ Unit, Eastern Taurides. The new species, probably re­strict­ed to the Pliens­bachian Orbitopsella Zone, is char­ac­ter­ized by a coarse agglutinated wall with an irregular, sub­epi­dermal polygonal net­work, a de­vel­oped spi­ral stage fol­lowed by a long uniserial cylin­dri­cal stage, and a sim­ple aper­ture. It dif­fers from the type species Sievoides kocyigiti Farinacci & Ekmekçi (2004) by a de­vel­oped spi­ral stage and stratigraphic po­si­tion (Pliensbachian). This new species is dis­trib­uted in the peri-Mediterranean plat­forms (Taurides, Apennines, Dinarides). The dis­cov­ery of Sievoides blumenthali in the Lower Jurassic con­firms the ear­li­er ap­pear­ance of the larg­er Foraminifera hav­ing a wall with a sub­epidermal net­work, which is known to be com­mon in the Mid-Late Jurassic.