Comment on “Does specialization imply rare fossil records of some benthic foraminifera: Late Palaeocene examples from the eastern Neo-Tethys (Meghalaya, NE India)” by Suman Sarkar [Palaeogeography, Palaeoclimatology, Palaeoecology 514 (2019) 124–134.]

Sarkar (2019: Does specialization imply rare fossil records of some benthic foraminifera: Late Palaeocene examples from the eastern Neo-Tethys (Meghalaya, NE India) Palaeogeogr., Palaeoclimatol., Palaeoecol. 514, 124–134) uses the “first occurrences” of two large benthic foraminifera (LBF), namely Haymanella paleocenica Sirel and Keramosphaera iranica Rahaghi, in the upper lower Paleogene (Thanetian) Lakadong Limestone of NE India for far-reaching speculations on autecology and specialization as well as paleobiogeography and migration patterns in the central and eastern Neotethyan realm. [Note: The authors requested post-submission that all instances of “paleocenica” made in the Abstract and Introduction be altered to “elongata”.] We believe that the true occurrences of such taxa in Late Paleocene shallow-water carbonates from NE India are not only speculative but irrelevant because they are based on incorrect identifications. On the basis of such documentation, Sar19 claimed that the sparse occurrences of both species can be correlated to their specialist behavior. Sar19 also added a more specific interpretation of the paleoecology of H. elongata and K. iranica relating them to the upper and lower parts of the upper photic zone, respectively. This conclusion is, in our point of view, not supported by the data and also conflicts with a bulk of publications supporting the opinion that the autecology of LBF must be interpreted by means of comparative anatomy with recent counterparts along with taphonomy and a comprehensive facies analysis of the host carbonates. We will show that the taxon identified by Sar19 as Keramosphaera iranica instead is assigned to the Orduella spherica Sirel, whereas the identification of Haymanella paleocenica (elongata) from NE India remains unverified. We will also show how, contrary to what is claimed by Sar19, the paleoecological model proposed is not substantiated by data. Finally, we will argue that, in the Paleocene and lower Eocene of central and eastern Neo-Tethys, the identification of a biogeographic region must be regarded with a focus on the faunal exchanges established within the so-called ‘Lockhartia Sea’.