Multiple Orbitoides d’Orbigny lineages in the Maastrichtian? Data from the Central Sakarya Basin (Turkey) and Arabian Platform successions (Southeastern Turkey and Oman)

The standard reconstruction of species of Orbitoides d'Orbigny into a single lineage during the late Santonian to the end of the Maastrichtian is based upon morphometric data from Western Europe. An irreversible increase in the size of the embryonic apparatus, and the formation of a greater number of epi-embryonic chamberlets (EPC) with time, is regarded as the main evolutionary trends used in species discrimination. However, data from Maastrichtian Orbitoides assemblages from Central Turkey and the Arabian Platform margin (Southeastern Turkey and Oman) are not consistent with this record. The Maastrichtian Besni Formation of the Arabian Platform margin in Southeastern Turkey yields invariably biconvex specimens, with small, tri- to quadrilocular embryons and a small number of EPC, comparable to late Campanian Orbitoides medius (d'Archiac). The upper Maastrichtian Tarakli Formation from the Sakarya Basin of Central Turkey contains two distinct, yet closely associated forms of Orbitoides, easily differentiated by both external and internal features. Flat to biconcave specimens possess a small, tri- to quadrilocular embryonic apparatus of Orbitoides medius-type and a small number of EPC, whereas biconvex specimens possess a large, predominantly bilocular embryonic apparatus, and were assigned to Orbitoides ex. interc. gruenbachensis Papp-apiculatus Schlumberger based on morphometry. The flat to biconcave specimens belong to a long overlooked species Orbitoides pamiri Meric, originally described from the late Maastrichtian of the Tauride Mountains in SW Turkey. This species is herein interpreted to be an offshoot from the main Orbitoides lineage during the Maastrichtian, as are forms that we term Orbitoides 'medius', since they recall this species, yet are younger than normal occurrence with the accepted morphometrically defined lineage. The consistent correlation between the external and internal test features in O. pamiri implies that the shape of the test is not an ecophenotypic variation, but appears to be biologically controlled. We, therefore, postulate that more than one lineage of Orbitoides exists during the Maastrichtian, with a lineage that includes O. 'medius' and O. pamiri displaying retrograde evolutionary features

A Palaeontological Geosite Example: Hasanağa Stream, Akçadağ, Malatya

Güncel veya eski bir jeolojik süreci, olayı veya özelliği ifade eden kayaç, mineral, fosil topluluğu, yapı, istif, yer şekli ya da arazi parçası jeosit olarak tanımlanır. Doğu Anadolu Bölgesinde, Malatya ili, Akçadağ ilçesinin kuzeybatısında yer alan Hasanağa Deresi boyunca yüzeyleyen bazı jeolojik birimlerde bulunan fosil topluluğunun, bu tanıma iyi bir örnek oluşturduğu görülür. Hasanağa Deresi boyunca izlenen jeolojik birimlerin yaşları Mesozoyik'ten Kuvaterner'e kadar değişmektedir. Hasanağa Deresi boyunca Tersiyer yaşlı tortul birim çeşitliliği, Eosen yaşlı Darende Formasyonu'nun Korgantepe, Yenice ve Asartepe üyeleri, Oligosen yaşlı Muratlı Formasyonu ve Erken Miyosen yaşlı Alibonca Formasyonu ile ifade olmaktadır. Hasanağa Deresi'nde Lütesiyen'den Oligosen'e kadar uzanan düzenli istifi oluşturan birimlerde bolca bulunan ve Nummulites, Alveolina ve Discocyclina'larla temsil edilen iri bentik foraminiferler'in jeolojik miras kapsamında değerlendirilmesi bu çalışmanın konusunu oluşturmaktadır.Hasanağa Deresi boyunca, vadinin her iki tarafında değişik boyutlu, bazılarının içinde yaşam izleri gözlenmiş olan çok sayıda mağara da bulunmaktadır. Sahip olduğu iri bentik foraminifer çeşitliliği ve bolluğu ile karstik oluşumlar ve bunlara kolay ulaşılabilirlik, bölgenin bilimsel önemini arttırmaktadır.Rock, mineral, fossil associations, structure, geological section, landforms or a part of land which they represent current or former geological process, event or a specialty is defined geosite. Some geologic units containing fossil associations and outcropping along Hasanağa Stream located in the northwest of AkÇadağ which is a settlement of Malatya city in Eastern Anatolia Region, is seen as a good example to this definition. The age of the geological units that outcrop along Hasanağa Stream ranges from Mesozoic to Quaternary. Diversity of Tertiary sedimentary units along Hasanağa Stream is represented by Korgantepe, Yenice and Asartepe members of Eocene Darende Formation, Oligocene Muratlı Formation and Lower Miocene Alibonca Formation. The geological units constitute a regular sequence range from Lutetian to Oligocene in Hasanağa Stream. Their abundant larger benthic foraminifera such as Nummulites, Alveolina and Discocyclina are the subject of this study and they have been evaluated within the scope of geological heritage. Along the Hasanağa stream also, there are many caves having traces of life in some of them, on both sides of the valley, in different sizes. Diversity of larger benthic foraminifera and karstic formations increases the scientific importance of the district