Mohd Shafi Bhat
@uct.ac.za
Postdoctoral fellow
University of Cape Town
Scopus Publications
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Scopus Publications
Mohd Shafi Bhat, Anusuya Chinsamy, and John Parkington
The Royal Society
Here we examine the tibial microstructure of modern and fossil angulate tortoises to assess the histology and growth from the late Miocene–early Pliocene, Pleistocene through to modern forms. The cross-sections of all the tibiae sampled revealed highly vascularized, uninterrupted, fibrolamellar bone tissue during early ontogeny, which suggests that early growth was fast. However, later in ontogeny, growth was slower, as indicated by the deposition of parallel-fibred bone tissue in the outer cortex, and even ceased periodically, as indicated by lines of arrested growth. Comparative analyses of the growth rates of the tortoises from different time periods showed that the tortoises from the late Miocene–early Pliocene Langebaanweg locality and from Diepkloof Rock Shelter had relatively slower growth rates under less optimal growth conditions. Additionally, these prehistoric specimens show extensive remodelling, and several generations of secondary osteons further suggest functional and/or metabolic stresses on the skeleton. Palaeoenvironmental reconstructions suggest that it was mostly cooler and drier with seasonal fluctuations in late Miocene–early Pliocene, and it is likely that Chersina responded to these conditions by having a lower rate of growth as compared with their modern counterparts, which thrive in the current prevailing more favourable Mediterranean type of climate.
Mohd Shafi Bhat, Debajit Datta, Sanghamitra Ray, and P. M. Datta
Informa UK Limited
Mohd Shafi Bhat, Christen D. Shelton, and Anusuya Chinsamy
Wiley
Mohd Shafi Bhat, Christen D. Shelton, and Anusuya Chinsamy
PeerJ
Despite its abundance in the Permian fossil record of South Africa, little is known about the life history of Anteosaurus. Here we examine the bone microstructure of multiple skeletal elements of Anteosaurus from the Tapinocephalus Assemblage Zone of the Karoo Basin. The bone histology of Anteosaurus magnificus reveals that the cortex is composed of highly vascularized, uninterrupted fibrolamellar bone tissue surrounding the inner spongy medullary region. However, the histology of two ribs and a previously described femur of another Anteosaurus taxon revealed an interrupted growth pattern with lines of arrested growth and peripheral rest lines occurring in the compacta, indicating periodic pauses in growth possibly linked to the slowing down of growth during maturity. Given that the fibula of the same individual has well-vascularised fibrolamellar bone tissue without any growth marks in the cortex; this suggests variation in skeletal growth. Based on our histological results, three growth dynamic stages are deduced for the genus Anteosaurus: (i) the earliest growth stage is represented by the predominance of highly vascularized, uninterrupted fibrolamellar bone tissue in the inner cortex, which suggests rapid periosteal bone deposition during early ontogeny; (ii) the next stage of growth shows periodic interruptions in the bone deposition as indicated by the deposition of lines of arrested growth; (iii) the third stage shows the development of lamellar bone tissue with rest lines in the peripheral part of the cortex suggesting a slowing down of growth prior to death. Most of the skeletal elements are characterized by thick bone walls, extensive secondary reconstruction and the complete infilling of the medullary cavity. However, the radius and a previously studied femur have open medullary cavities with struts of bony trabeculae. Based on histologic structures and comparisons with extant taxa, it is likely that Anteosaurus may have been more terrestrial as its osteology point towards terrestriality, but it may have occasionally inhabited ephemeral pools like modern semi-aquatic Hippopotamus.
Mohd Shafi Bhat, Anusuya Chinsamy, and John Parkington
Wiley
Mohd Shafi Bhat, Sanghamitra Ray, and P. M. Datta
Cambridge University Press (CUP)
AbstractThe Upper Triassic Tiki Formation of India has yielded several new cynodont taxa, which are described on the basis of multiple isolated teeth and a jaw fragment. A new species of dromatheriid, Rewaconodon indicus, is defined by a tri- and tetracuspid asymmetric crown, long anterior edge of the major cusp a, cingular cusps d and f, and marked constriction at the crown-root junction. Another new dromatheriid, Inditherium floris n. gen. n. sp., is characterized by a broad, flower-shaped pentacuspid crown, multiple cingular cusps, and a weak lingual cingulum is also described from the same horizon. In addition, a new mammaliamorph taxon, Tikiodon cromptoni n. gen. n. sp., is established on a tooth specimen, which has a shovel-shaped crown, three closely spaced main cusps, a pronounced lingual cingulum with multiple cingular cusps, and a root of incomplete root bifurcation. Such a tooth morphology occupies an intermediate position between the non-mammalian cynodonts and the early mammals, as is evident from the co-occurrence of various cynodont dental morphotypes in the Tiki Formation. Moreover, Late Triassic cynodonts occurred along narrow belts demarcated by paleolatitudes, though the Indian fauna shows both Laurasian and Gondwanan affinities.UUID: http://zoobank.org/c2c575ad-ee23-4f33-8a30-661c548a5b17
Mohd Shafi Bhat, Christen Shelton, and Anusuya Chinsamy
Polska Akademia Nauk Instytut Paleobiologii (Institute of Paleobiology, Polish Academy of Sciences)
Sanghamitra Ray, Mohd Shafi Bhat, and P. M. Datta
Informa UK Limited
ABSTRACT A new rich and varied assemblage of archosauriform teeth is reported from the Upper Triassic Tiki Formation of India. Twelve morphotypes are identified based on their distinctive morphology, crown proportions, nature of serrations/denticles and serration density. Morphotypes I and II show similarity with that of Galtonia and Protecovasaurus, respectively, whereas morphotypes III–VI have low, subtriangular or leaf-shaped, asymmetrical, labiolingually compressed crowns with lenticular-subcircular bases and are diagnosed as belonging to different indeterminate archosauriforms. Morphotype VII shows similarity with aetosaur teeth, whereas morphotypes VIII–XII are ziphodont teeth having high, cylindrical, recurved crown with labiolingual compression, serrated carinae and subrectangular serrations, and are theropod-like. Variation in dental histology is noted between these morphotypes based on extent of pulp cavity, dentinal tubules and von Ebner lines of incremental growth. In multivariate analyses, there is considerable overlapping of convex hull polygons with morphospaces of other known archosauriforms such as Protecovasaurus, Crosbysaurus and Tecovasaurus known from the lower Tecovas Formation of the Chinle Group, USA. Such similarity correlates the two horizons despite wide geographic separation, suggesting that the age of the Tiki Formation may be younger than that previously suggested. Based on the known fossil flora and fauna, a mid-late Carnian age is proposed for the Tiki Formation.
Mohd Shafi Bhat and Sanghamitra Ray
Informa UK Limited
ABSTRACT Numerous tooth plates of different types were recovered from the Upper Triassic Tiki Formation of India. Sharp crested tooth plates with five acute ridges, tubercles on the crests, robust and deep furrows, wide spaces between successive ridges and reticulate ornamentation on the occlusal surfaces are assigned to a new species of the dipnoan genus Ptychoceratodus. Another tooth plate, characterized by four ridges with conical and cusplet-like denticles is identified as a Gnathorhiza. This is the first record of gnathorhizid fishes from the Upper Triassic sediments around the world. The Tiki aquatic realm was inhabited by different types of fishes including freshwater sharks, omnivorous/carnivorous dipnoans and other bony fishes. Palaeobiogeographic distribution of the dipnoans suggests that these were restricted to a high palaeolatitude in the southern hemisphere, where co-occurrences of several genera are seen in India.
Mohd Shafi Bhat, Anusuya Chinsamy, and John Parkington
Wiley
The current study deduced the growth pattern and lifestyle habits of Chersina angulata based on bone histology and cross‐sectional geometry of limb bones. Femora, humeri, and tibiae of seven different‐sized individuals representing different ontogenetic stages were assessed to determine the interelement and intraskeletal histological variation within and among the tortoises. The bone histology of adult propodials consists of a highly vascularized, uninterrupted fibrolamellar bone tissue with a woven texture in the perimedullary and midcortical regions suggesting overall fast early growth. However, later in ontogeny, growth was slow and even ceased periodically as suggested by slowly formed parallel‐fibered bone tissue and several growth marks in the pericortical region. In juvenile individuals, fibrolamellar bone tissue is restricted to the perimedullary regions of propodials as remnants of bone formed during the earliest stages of ontogeny. The epipodials are characterized by having parallel‐fibered bone tissue present in their cortices; however, periodic arrests in growth are recorded at various times. Remnants of fibrolamellar bone tissue formed during early ontogeny occur in the epipodials of only a few individuals. Interelement variation is evident, in terms of variation in the orientation of vascular canals between individuals and within the same diaphyseal cross‐sections. Different elements show varying cross‐sectional geometry, which appear to be correlated with the fossorial behavior of the species. Our results show that of all the long bones, the tibia is least remodeled during ontogeny and it is therefore the best element for skeletochronology.
Nibedita Rakshit, Mohd Shafi Bhat, Debarati Mukherjee, and Sanghamitra Ray
Wiley
Mohd Shafi Bhat, Sanghamitra Ray, and P.M. Datta
Elsevier BV
Nibedita Rakshit, Mohd Shafi Bhat, Sanghamitra Ray, and P.M. Datta
Elsevier BV
Mohd Shafi Bhat, Sanghamitra Ray, and P. M. Datta
Cambridge University Press (CUP)
AbstractA new lonchidiid genus,Pristrisodus, from the Upper Triassic Tiki Formation of India is described based on multiple, well-preserved, isolated teeth. Comparative analysis resulted in synonymizingParvodus tikiensisandLissodus duffini,which are known from the same horizon and resulted in a new taxon,Pristrisodus tikiensisn. comb. These teeth are elongated with mesiodistal length greater than or equal to twice the labiolingual width and have a high principal cusp, lateral cusplets, a distinct ridge near the crown-root junction labially and higher up on the crown lingually, weak ornamentation, and linear depression along the crown-root junction. Five morphotypes based on overall shape, robustness and crown height are determined. The teeth show a gradual monognathic heterodonty. The anterolateral teeth (morphotypes I−II) have high, pyramidal principal cusp with two or three small but pointed cusplets, and triangular labial and lingual protuberance. The posterolateral teeth (morphotypes III−IV) have four incipient cusplets, relatively low principal cusp, bilobed/rounded, hanging labial and incipient lingual protuberances. Morphotype V comprises anterior teeth that are broad, triangular and robust, and have rounded/blunt principal cusp, one cusplet, and low, hanging labial peg. Multivariate analyses corroborate the qualitative assessment of the Indian hybodonts. Dental histology ofPristrisodusn. gen., shows that it is distinctly different from other lonchidiid genera. The assemblage of freshwater sharks, along with other vertebrate microfossils of the Tiki Formation, shows similarity with that of the lower Tecovas Formation of the Chinle Group, USA. The euryhaline nature resulted in the adaptation of the hybodonts to freshwater systems in India during the Carnian.
Mohd Shafi Bhat
Springer Science and Business Media LLC
Vertebrate microfossils are valuable entities for the reconstruction of ancient ecosystems but difficult to find without using microscopes, resulting in a collection bias towards the macrofossils, which are easily visible to the naked eyes. The current study gives a comprehensive description of the protocols applied for systematic exploration and extraction of vertebrate microfossils. Initial assessment of the microsites for fossil-richness is carried out by spot sampling using coning and quartering, which is a technique applied for the first time. Subsequently, lithologs are prepared to ascertain the microfossil-bearing stratum, bulk samples are collected, screened by wet and dry sieving methods and residues examined under a microscope for extraction of vertebrate microfossils. These well-designed procedures are systematically applied for collection of vertebrate microfossils from the Upper Triassic Tiki Formation of the Rewa basin. More than 8000 kg of Tiki mudrocks collected as bulk samples, have yielded a rich and diverse array of vertebrate microfossils. The fauna incorporates different types of fresh water sharks, bony fishes, small temnospondyls, and varied r eptiles such as the archosauriforms, lepidosauromorphs, and cynodonts. These findings highlight the efficiency of the proposed methodology.