The plant Leclercqia (Lycopsida) in Gondwana: implications for reconstructing Middle Devonian palaeogeography

Abstract

Abundant and well-preserved material of the ligulate lycopsid genus Leclercqia is reported from a new Middle Devonian locality in northeastern Queensland (Australia). The plants occur in a chert horizon in the Storm Hill Sandstone of the Dosey-Craigie Platform. Lithological data and conodont analyses combined with information from in situ spores provide an age for the plant levels ranging from Eifelian, possibly Middle Eifelian, to Early Givetian. Plant taxonomic identification is based on vegetative and fertile stems that display both external morphology and anatomy. This material represents the best documented occurrence of Leclercqia outside Laurussia and possibly the earliest in Gondwana; it provides evidence that colonization of Gondwana by the species L. complexa was contemporaneous to that of Siberia and Kazakhstan. Analysis of the distribution patterns of L. complexa suggests that it was adapted to a wide range of environments, but within certain limits which we hypothesize to be those of a climatic belt. Such considerations support previous studies using other biological data, such as faunas and palynomorphs, for reconstructing Devonian palaeogeography. They favour a close proximity of Laurussia and Gondwana rather than the occurrence of a wide ocean separating the two palaeocontinents in Middle Devonian times.

Middle Devonian herbaceous lycopsid Haplostigma from the Paraná Basin, Brazil: Taxonomy, biostratigraphy and Phytogeography

“…Paleobotanical data from the Early to Late Devonian of South America (Edwards and Benedetto, 1985;Berry et al, 2000;Gerrienne et al, 2001;Di Pasquo et al, 2009;2013;Matsumura et al, 2013;, South Africa (Seward, 1932;Plumstead, 1967;Anderson and Anderson, 1985), Antarctica (Mildenhall and Schopf, 1980;McLoughlin and Long, 1994) and Australia (McLoughlin and Long, 1994;Meyer-Berthaud et al, 2003) support the hypothesis of the existence of a distinct phytogeographic domain, named the Gondwanan Realm by Edwards (1990a) (Wnuk, 1996).…”

The Middle Devonian plant assemblage from Dechra Aït Abdallah (Central Morocco) revisited

“…The stratigraphic record of this species ranges from the late Emsian to the late Givetian. Remains of L. complexa are reported from the paleoregions Laurussia (USA, Canada, Europe) (Gensel and Albright, 2006), Kazakhstan (including Xinjiang; Xu and Wang, 2008;Xu et al, 2011), Gondwana (Berry, 1994;Meyer-Berthaud et al, 2003) and probably Siberia (Berry, 1996). 5.2.2.2.…”

A new Late Devonian isoetalean lycopsid from New South Wales, Australia: Cymastrobus irvingii gen. et sp. nov

“…Hill et al (1999) report a diversification in systematics paralleled by one in growth habit in floras of late Early to early Late Devonian age (late Emsian to Frasnian). The herbaceous lycopsids of this time interval are assigned to Leclercqia complexa (Fairon-Demaret, 1974;Meyer-Berthaud et al, 2003). Those identified in the Eifelian locality of Storm Hill in the Broken River area of north-eastern Queensland, are a good example.…”