Araneograptusgen. nov. and its two species from the late Tremadocian (Lancefieldian, La2) of Victoria

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Abstract
The middle Lancefieldian (late Tremadocian) dissepimentous siculate graptolites Dictyonema macgillivrayi T. S. Hall 1897 and D. pulchellum T. S. Hall 1899 possess a biradially symmetrical proximal end development which appears to be fully homologous with Clonograptus. For this reason and because of the apparent absence of bithecae and/or basal attachment structures, these species have to be removed from either Dictyonema or Rhabdinopora. The new genus Araneograptus is introduced for such dissepiment-bearing clonograptids. The mature development of fully cone-shaped rhabdosomes of A. pulchellus is contrasted with the mostly horizontal development of A. macgillivrayi. Possible relations with other late Tremadocian (or early Arenigian) ‘heavy-meshed’ species, such as ‘Dictyonema’ murrayi J. Hall, 1865 are discussed.