Cambrian trilobite Ovatoryctocara granulata Tchernysheva,1962 and its biostratigraphic significance

Cambrian trilobite Ovatoryctocara granulata Tchernysheva,1962 and its biostratigraphic

significance

Jinliang Yuan;Yuanlong Zhao;Jin Peng;Xuejian Zhu;Jih-pai Lin

【期刊名称】《自然科学进展（英文版）》 【年(卷),期】2009(019)002

【摘要】The genus Ovatoryctocara Tchernysheva, 1962, and its key species Ovatoryctocara granulata Tchernysheva, 1962, are revised. Ovatoryctocara granulata occurs near the base of the Ovatoryctocara Zone and ranges up into the lower portion of the Kounamkites Zone in the Siberian Platform. O. Granulata also appears in southeastern Guizhou, South China, but O. Granulata in northern Greenland may represent an indefinite species. Specimens of Ovatoryctocara from Newfoundland cannot be identified to species level. Specimens include-ing two cranidia and three pygidia from the lower part of the Aoxi Formation at Yaxi Village, Shizhu Town, eastern Tongren, north-eastern Guizhou, were previously assigned to O. Granulata, which is now reassigned as a new species O. Yaxiensis sp. Nov. It bears the following main features: glabella club-shaped, slightly expanded medially, with four pairs of lateral furrows, of which S1-S3 are trian-gular pits, S4 is shallow, connecting with axial furrow; shorter palpebral lobe situated a little anterior to the midway of facial suture across the fixigenae, longer