Quantitative Study On The Morphology Of Conotubus

The late Ediacaran Gaojiashan biota, located in the Ningqiang-Mianxian area (southern Shaanxi Province, South China), sheds important paleobiological insights into our understanding of the evolutionary history of early life at the Precambrian-Cambrian boundary. The genus Conotubus is only known from the Gaojiashan biota and is of great paleobiological importance for metazoan origination.Previous study has led to morphological, systematic, and taphonomic documentations of Conotubus. However, morphological reconstruction of Conotubus remains poorly understood, largely limited by analytic means (e.g., statistic measurements). This would lead to an indefinite phylogenetic assessment of Conotubus.On the basis of quantitative paleobiological documentation of Conotubus, we suggest that 1) the tube has a constant morphology at the middle part; 2) connective tissues existed at the boundary between the middle and posterior parts of the tube; 3) morphology of anatomy outside the aperture is reconstructed; 4) the tube has roughly constant length and diameter ratios that can be expressed by a function line of W=2/3L; 5) the "tentacles" are more reasonably re-interpreted; 6) a more precise morphological reconstruction is provided; 7) plot diagram shows that the length and diameter ratios of the posterior part of the tube are restricted to a area defined by function lines W=0.4L and W=0.12L and are concentrated on around W=0.18L; 8) Conotubus are possibly colonial, sessile organisms.