naa a22 4500 510756646 CHVBK 20180411083125.0 cr unu---uuuuu 180411e20131001xx s 000 0 eng 10.1007/s12594-013-0160-1 doi (NATIONALLICENCE)springer-10.1007/s12594-013-0160-1 Systematics, biometry of the species Opsidiscus from the Middle Cambrian succession of the Spiti basin, India [Elektronische Daten] [Shivani Pandey, Suraj Parcha] The Middle Cambrian succession of the Parahio Valley in general and Debsakhad section in particular is dominated by trilobites. Genus Opsidiscus, along with other trilobite forms dominates the lower Middle Cambrian succession. In the present study two new species of Opsidiscus, Opsidiscus wadiai and Opsidiscus srikantiai are reported from the lower Middle Cambrian succession of Debsakhad section. The species were differentiated on their morphological features and their multivariate analysis. The multivariate analysis applied here is used as a supplement method to qualitative analysis in order to differentiate between the cranidial characters of Opsidiscus. The qualitative study of each species studied individually shows more or less close affiliation as is observed by different quantitative methods. The presence of Opsidiscus has a great stratigraphic significance in this region, as they first appear from informal Stage 5 of Series 3 and goes up to the Drumian Stage of Series 3 of the Cambrian System in the Debsakhad section, which helps to correlate this section with other well known sections of the Middle Cambrian. Geological Society of India, 2013 Spiti nationallicence Opsidiscus nationallicence Middle Cambrian nationallicence multivariate analysis nationallicence Pandey Shivani Wadia Institute of Himalayan Geology, Gen. Mahadeo Singh Road, 248 001, Dehra Dun, India aut Parcha Suraj Wadia Institute of Himalayan Geology, Gen. Mahadeo Singh Road, 248 001, Dehra Dun, India aut Journal of the Geological Society of India Springer India 82/4(2013-10-01), 330-338 0016-7622 82:4<330 2013 82 12594 https://doi.org/10.1007/s12594-013-0160-1 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s12594-013-0160-1 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Pandey Shivani Wadia Institute of Himalayan Geology, Gen. Mahadeo Singh Road, 248 001, Dehra Dun, India aut NATIONALLICENCE 700 1- Parcha Suraj Wadia Institute of Himalayan Geology, Gen. Mahadeo Singh Road, 248 001, Dehra Dun, India aut NATIONALLICENCE 773 0- Journal of the Geological Society of India Springer India 82/4(2013-10-01), 330-338 0016-7622 82:4<330 2013 82 12594 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer