Reinterpretation of a Conulariid-Like Fossil From the Vendian of Russia

Abstract

Vendoconularia triradiata Ivantsov and Fedonkin, recently described from Vendian (latest Proterozoic) strata of Russia, has been interpreted as a six-sided conulariid cnidarian. However, comparison of published illustrations of V. triradiata with Palaeozoic conulariids suggests that certain key features of the anatomy of V. triradiata should be reinterpreted. Specifically, features previously homologized with the corners of conulariid thecae may actually be homologous to the conulariid midlines.Under this new interpretation, the corners of the Vendoconularia theca were sulcate, and the midline of each face was non-sulcate and flanked by a pair of low internal carinae. This alternative set of hypotheses of homology makes the argument for a conulariid affinity for Vendoconularia stronger.

Cladistic Analysis of the Suborder Conulariina Miller and Gurley, 1896 (Cnidaria, Scyphozoa; Vendian–triassic)

“…These include all conulariid‐like small shelly fossils ( Arthrochites , Carinachites , Emeiconularia and Hexaconularia ; Conway Morris and Chen 1992; Qian Yi et al . 1997; Van Iten et al. 2005) and all genera of circonulariids ( Australoconularia, Circonularia and Garraconularia ; Bischoff 1978; Van Iten 1992 a ).…”

“…Since the publication of the TIP, circonulariids (Silurian–Devonian), which differ from pyramidal conulariids in having a conical skeleton (Bischoff 1978; Van Iten 1992 a ), and certain pyramidal small shelly fossils from the Lower Cambrian (Conway Morris and Chen Menge 1992), have also been classified as conulariids. Most recently, Van Iten et al. (2005) proposed a possible rationale, based on cladistic principles, for the inclusion of conulariids, circonulariids and conulariid‐like small shelly fossils in a single, putatively monophyletic group that excludes all other taxa.…”

Darwin's dilemma: the realities of the Cambrian ‘explosion’

“…Nevertheless, there are candidate cnidarians. Perhaps the most convincing are in the form of conulariids (van Iten et al 2005), as well as some of the frond-like forms that also occur as Ediacaran 'survivors' in the Cambrian (Conway Morris 1993). Another apparently reliable metazoan is the quasi-mollusc Kimberella, which is associated with tracks and apparent feeding traces in the form of scratch arrays (e.g.…”

Armoured test of Early Devonian Mesoconularia (Conulariida) from the Prague Basin (Czech Republic): probable adaptation to increased predation pressure

“…They are generally classified as scyphozoans most closely related to extant coronates or staurozoans (e.g. Kiderlen 1937;Werner 1966aWerner , b, 1967Werner , 1970Van Iten 1991;Jerre 1994;Hughes et al 2000;Van Iten et al 2006a-c, 2008, 2014bLeme et al 2008a) although other interpretations have been proposed (Termier & Termier 1953, Kozłowski 1968, Bischoff 1973, Babcock & Feldmann 1986a, Feldmann & Babcock 1986, Babcock 1991. The microstructure and growth of the conulariid test have been investigated by a number of authors in recent years (e.g.…”

“…The microstructure and growth of the conulariid test have been investigated by a number of authors in recent years (e.g. , 2006aJohn et al 2010;Ford 2011;Robson & Young 2013;Ford et al 2016), but the first studies are of a much earlier date. Bouček & Ulrich (1929) presented the first study of the microstructure of conulariid tests.…”