Journal of Iberian Geology

, Volume 45, Issue 2, pp 317–340 | Cite as

Taxonomy, morphometry and morphospace of cranial bones of Panthasaurus gen. nov. maleriensis from the Late Triassic of India

  • Sanjukta ChakravortiEmail author
  • Dhurjati Prasad Sengupta
Research Paper


Metoposaurids are an important Late Triassic temnospondyl family known from nonmarine sediments of Europe, North-America, North Africa and India. Indian taxon Metoposaurus maleriensis became Buettneria maleriensis. “Metoposaurus” was thereafter restricted to encompass only M. diagnosticus from Germany and M. bakeri from North America, whose lacrimals are excluded from the orbital margin. However, some specimens of M. diagnosticus also exhibit lacrimals contributing to the orbital margins, as in Buettneria. Also, the generic name Buettneria was preoccupied, and Koskinonodon represents the senior synonym. Hence, the taxonomic status of the Indian metoposaurids became questionable. Metoposaurids being extremely conservative in nature, no single character could be assigned to distinguish them at the species level and there is no alpha level taxonomy available. Assigning a taxonomic status of the Indian taxon along with alpha taxonomy of all the other metoposaurids viewed through the lights of morphometry and morphospace is the main purpose of this paper. All genera were studied first hand from different museums of the world. Detailed measurements of skull bones and morphological properties are critically appraised. Biometric studies were done to analyse the variation between different taxa. Morphospace of different bones are constructed after conducting elliptical Fourier analysis and PCA using R. Cladogram using TNT and comparison of the cranial morphology is provided. Fourteen parsimonious trees, 50% majority rule consensus, Bremer support value and bootstrap resampling all reveals that Indian taxon occupies a distinct position somewhere between the European Metoposaurus and North American Koskinonodon. This fact corroborates with the morphospace analysis. There is also a strong bio geographic correlation in the fact that the Indian taxon was widely separated from the main cluster of the European and the North American taxa. Panthasaurus gen. nov. maleriensis is erected for the Indian taxon of metoposaurids. Biometry and morphospace studies supports Indian Metoposaurus to be a separate taxon.


Metoposauridae India Morphometry Morphospace Taxonomy 


Los metoposáuridos son una importante familia de temnospóndilos del Triásico Superior conocida de sedimentos no marinos de Europa, Norte América, Norte de África e India. El taxón Indio Metoposaurus maleriensis se convirtió en Buettneria maleriensis. “Metoposaurus” fue posteriormente restringido para englobar solamente M. diagnosticus de Alemania y M.bakeri de Norte América, cuyos lacrimales están excluidos del margen orbital. Sin embargo, algunos especímenes de M. diagnosticus también exhiben lacrimales que contribuyen a los márgenes orbitales, como en Buettneria. Además, el nombre genérico Buettneria era presentaba problemas, dado que Koskinonodon es el sinónimo juvenil. Por lo tanto, el estatus taxonómico de los metoposáuridos indios se convirtió en cuestionable. Los metoposáuridos, siendo de naturaleza extremadamente conservadora, no presentan un solo carácter que pueda ser asignado para distinguirlos a nivel de especie y no se dispone de una taxonomía alfa para este grupo. Asignar un estatus taxonómico al taxón Indio junto con una taxonomía alfa del resto de metoposáuridos vista a través de la luz de la morfometría y morfoespacio son los principales propósitos de este artículo. Los géneros, procedentes de diferentes museos de todo el mundo, fueron estudiados por primera vez. Las medidas de detalle de los huesos craneales y propiedades, morfológicas han sido evaluadas críticamente. Los estudios biométricos fueron también realizados para analizar la variación entre diferentes taxones. El morfoespacio de diferentes huesos fue construido después de realizar análisis elípticos de Fourier y PCA usando R. Se presentan cladogramas usando TNT y comparación de la morfología craneal. Catorce arboles parsimoniosos, regla del cincuenta por ciento del consenso de la mayoría, valores de Bremer Support y remuestreo por bootstrap revelan en todos los casos que el taxón Indio ocupa una posición distinta en algún lugar entre el taxón europeo Metoposaurus y el taxón norteamericanos Koskinonodon. Este hecho se corrobora con los análisis de morfoespacio. Existe también una fuerte correlación biogeográfica en el hecho que el taxón Indio está ampliamente separado del clúster principal de los taxones europeos y norteamericanos. Panthasaurus gen. nov. maleriensis se erige como el taxón Indio de metoposáuridos. Estudios biométricos y de morfoespacio soportan que los metoposáuridos Indios correspondan a un taxón separado.

Palabras clave

Metoposauridae India Morfometría Morfoespacio Taxonomía 



One of the authors (SC) acknowledges the authorities of MNHN, Paris including Dr. Damien Germain for allowing us to study their collection. SC thanks Dr. Josep Fortuny for sharing his images with us thereby enriching our data. SC also thanks Dr. Brussate and Dr. Sulej for sharing their images. SC acknowledges Dr. Julien Claude for his help in R and for other useful advice. She also thanks Thomas Arbez for all his support during her stay. The authors thank the organisers of the special seminar on “Early tetrapods awaken—New insights into the evolution of temnospondyls” as a part of the European Association of Vertebrate Paleontologists annual meeting at Harlem, 2016. The authors also thank the reviewers Josep Fortuny, Bryan G and a third reviewer whose critical comments enriched the manuscript. They also thank the authorities of the Indian Statistical Institute for funding and for providing infrastructural support. DPS wants to acknowledge the late Prof. T. K. Roychowdhury of Indian Statistical Institute for introducing him to the world of the metoposaurid amphibians.

Supplementary material

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Supplementary material 1 (DOCX 5035 kb)


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© Springer Nature Switzerland AG 2018

Authors and Affiliations

  1. 1.Indian Statistical InstituteKolkataIndia

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