Open Journal of Geology, 2011, 1, 51-55 doi:10.4236/ojg.2011.13006 Published Online October 2011 (http://www.SciRP.org/journal/ojg) Copyright © 2011 SciRes. OJG Subterraniphyllum thomasii Elliott, Fossil Calcareous Alga the Evolutionary Link between Geniculate and Nongeniculate Coralline Algae: A Hypothesis Shyam N. Mude 1* , P. Kundal 2 1 Department of Geology, Fergusson College, Pune, India 2 Postgraduate Department of Geology, RTM Nagpur University, Law College Square, Nagpur, India E-mail: * shyammude25@yahoo.co.in Received June 12, 2011; revised July 27, 2011; accepted September 3, 2011 Abstract The Neogene sediments exposed in the Saurashtra region along the southwest coast India, consists of well preserved diversified coralline algae [1-5].The Subterraniphyllum thomasii Elliott, a fossil Calcareous alga has been reported from the Dwarka Formation (Lower to Middle Miocene) from Porbandar area, Saurashtara, Indian subcontinent. This is the first report of Subterraniphyllum thomasii Elliott from Lower-Middle Mio- cene sediments from the Indian subcontinent; however it has been documented earlier from Late Lutetian sediments of Kachchh Basin, India. There is a controversy regarding the generic placement of the extinct species Subterraniphyllum thomasii Elliott as distinct genus of the geniculate coralline algae or not i.e. non- geniculate coralline algae [6,7]. However, the present specimens of Subterraniphyllum thomasii Elliott ex- hibit pinpointing features of both geniculate and nongeniculate coralline algae. Finally on the basis of our observations, we hypothesize that Subterraniphyllum thomasii Elliott may be transitional species and evolu- tionary link between geniculate and nongeniculate coralline algae. Keywords: Subterraniphyllum thomasii Elliott, Evolutionary Link, India 1. Introduction The Cenozoic sediments of the Porbandar area are clas- sified as Gaj Formation (Lower Miocene), Dwarka For- mation (Lower-Middle Miocene), Miliolite Formation (Early Middle-Late Pleistocene) and Chaya Formation (Late Pleistocene-Late Holocene) [8] (Figure 1). Coral- line algae are the dominant constituents of shallow water sedimentary rocks throughout the Cenozoic Era [9] and they have also a potential as paleo-environmental and paleo-bathymetrical indicators, which are deduced by comparison of fossil algal assemblage with environ- mental and geographical distribution of modern algal associations [10,11]. The paper incorporates the observa- tions made during the present study; the discussion on the placement of Subterraniphyllum thomasii Elliott and proposal of a hypothesis which would throw some light on the anatomy of this species and possibly help to find the placement of this species within Corallinales. 2. Methodology The thin sections of algae bearing rock sample have been prepared and examined under Lieca-Make Binocular Pe- trological Microscope. Seventeen sample of Subterrani- phyllum thomasii Elliott have been observed and analyzed. 3. Classification and Taxonomy Division: Rhodophyta Wittstein, 1901 Class: Rhodophyceae Rabenhorst, 1863 Order: Corallinales Silva and Johansen, 1986 Family: Corallinaceae Verheij, 1993 Subfamily: Corallinoideae ? Genus: Subterraniphyllum Elliott Species: Subterraniphyllum thomasii Elliott 4. Systematic Description The segments consist of cylindrical intergenicula with