Araucariaceae (Pinopsida): Aspects in Palaeobiogeography and Palaeobiodiversity in the Mesozoic$ Lutz Kunzmannã
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ARTICLE IN PRESS Zoologischer Anzeiger 246 (2007) 257–277 www.elsevier.de/jcz Araucariaceae (Pinopsida): Aspects in palaeobiogeography and palaeobiodiversity in the Mesozoic$ Lutz Kunzmannà Museum fu¨r Mineralogie und Geologie, Staatliche Naturhistorische Sammlungen Dresden, Ko¨nigsbru¨cker Landstrasse 159, D-01109 Dresden, Germany Received 25 January 2007; received in revised form 13 August 2007; accepted 17 August 2007 Corresponding editor: U. Fritz Abstract The paper examines recent information on the history of the ‘southern hemisphere’ conifer family Araucariaceae and gives supplementary notes to previously published monographs. Important data from the Mesozoic fossil record are presented and summarized to describe the ancient diversity and distribution of Araucariaceae. Information on the origin of the family and oldest fossil records of the present-day genera are assembled. Existing models on phylogenetic relationships within the family inferred from molecular data are compared with relationships between the genera determined from morphological data. Reasons for disappearance of representatives of this conifer family in the latest Cretaceous in North America and Europe are briefly discussed. r 2007 Elsevier GmbH. All rights reserved. Keywords: Araucariaceae; Palaeobiodiversity; Palaeobiogeography; Fossil conifers; Fossil record; Mesozoic 1. Introduction heterophylla (Salisbury, 1807) Franco, 1952. Discovery of the very rare species Wollemia nobilis Jones, Hill and Araucariaceae Henkel and Hochstetter, 1865 have Allen, 1995 in the Wollemi National Park in the Blue long fascinated both botanists and palaeobotanists. Mountains, SE Australia, typify Araucariaceae again as Araucarian trees often express an unusual canopy a very distinctive and phylogenetically old family of architecture which characterizes them as ‘‘living fossils’’ conifers. Due to their today’s distribution, Araucaria- among conifers (Fig. 1). These visually striking trees are ceae are considered as a southern hemisphere family important as plantation trees in some countries and also with a typical Gondwanan relict area (e.g., Page 1990; interesting for gardening. Several species are common Enright and Hill 1995). ornamental trees all over the world, e.g., Araucaria Petrified seed cones and petrified trunks of araucarian araucana (Molina, 1782)K.Koch, 1873 and Araucaria trees are among the most beautifully preserved and most attractive plant fossils (Fig. 2). But, fossil remains of Araucariaceae are sparse and rare in the fossil record in $ Modified version of a lecture presented at the 48th Phylogenetic most parts of the world (Kershaw and Wagstaff 2001). Symposium on Historical Biogeography, Dresden, November 24–26, 2006. It is because: (1) Araucariaceae might not often have ÃTel.: +49 351 8926 406; fax: +49 351 8926 404. dominated forest vegetation in the past, (2) fossilisation E-mail address: [email protected]. of their critical organs usually needs special conditions, 0044-5231/$ - see front matter r 2007 Elsevier GmbH. All rights reserved. doi:10.1016/j.jcz.2007.08.001 ARTICLE IN PRESS 258 L. Kunzmann / Zoologischer Anzeiger 246 (2007) 257–277 Fig. 1. Araucaria araucana (Molina, 1782)K.Koch, 1873 in Andean Araucaria-Nothofagus forest, 1.200 m above sea level, near Paso Tromen, Villarrica National Park, Chile. Fig. 2. Araucaria alvarezii Dernbach and Jung, 2002 [nom. non rite publ.], petrified seed cone, Early Cretaceous, province and (3) fossil remains of Araucariaceae were recognized Chubut, Patagonia, Argentina, Palaeobotanical collection up to now generally sparse in the sediments. Palaeobo- Museum of Mineralogie and Geologie Dresden, Germany tanical studies have assigned Araucariaceae as the most (MMG PB SAK 53:1). ‘basal’ among the extant conifer families. They appear to have been distinctive since at least the Late Triassic (Stockey 1994) nested within the Voltziales. In the 2. Extant representatives and their distribution Mesozoic, they show a bi-hemisphere distributional areas pattern with records in Gondwana and Laurasia. Fossil evidence suggests that from the Cretaceous-Palaeogene Araucariaceae form a distinctive family of conifers boundary to present, the family has gradually declined without very close affinities to other living families in number of taxa and geographic distribution (Taylor (Page 1990). Phylogenetically, Araucariaceae are sister and Taylor 1993). Araucariaceae disappeared in the to Podocarpaceae (including Phyllocladaceae); both latest Cretaceous from the palaeovegetation in most forming the sister group of Cupressaceae s. l., Taxaceae, parts of the northern hemisphere. Cephalotaxaceae and Sciadopityaceae (Stefanovic´et al. Much of the former work on fossil Araucariaceae 1998). This is also clearly indicated by different seed was summarized by Stockey (1982, 1994). Enright and cone morphologies (Farjon 2001, 2005). Araucariaceae Hill (1995) and Kershaw and Wagstaff (2001) have and Podocarpaceae as typical ‘southern hemisphere’ focused on southern hemisphere records in their families share a common ancestry from many points of comprehensive treatises. An annotated compendium view (Miller 1988). on published records is edited by Dijkstra et al. (1999). Living Araucariaceae consist of the three well- The present paper gives an updated state of the art with established genera Agathis Salisbury, 1807, Araucaria special consideration of European fossil data from the Jussieu, 1789 and Wollemia Jones, Hill and Allen, 1995, Mesozoic. numbering 41 species and one variety (Farjon 2001). ARTICLE IN PRESS L. Kunzmann / Zoologischer Anzeiger 246 (2007) 257–277 259 Fig. 3. Recent distribution of Agathis Salisbury, 1807 (compiled from Farjon 2001; Enright and Hill 1995). Agathis is mostly distributed in the ecozones of free part of the ovuliferous scale, and free seeds with two Indomalaya and Australasia (Fig. 3) with two relatively marginal asymmetrically developed wings. Cone scales diverse regions in Borneo (5 spp., 4 endemic) and in and seeds are shed separately at maturity. Cuticular New Caledonia (5 spp., all endemic). In all other regions micromorphology of Agathis leaves is characterized by not more than two species occur (Farjon 2001). Much of stomata with Florin rings (Stockey 1993). Species of its distribution area covers the Malesian botanical Agathis are monoecious. province (Malay Peninsula, Sumatra, Borneo, Philip- In contrast, Araucaria has a disjunct distribution with pines, New Guinea) which straddles the boundary most species occurring in the Australasian ecozone between Indomalaya and Australasia. Agathis may be (Australia, New Guinea, New Caledonia, Norfolk called the ‘most tropical’ among present-day conifer Island) too, but two species are distributed in South genera concentrated in montane tropical to subtropical America (Fig. 4). This disjunction is a characteristic rainforests. Only Agathis australis occurs in warm- feature of Gondwanan relict elements. New Caledonia is temperate humid rainforest in northern New Zealand. the most diverse region with 13 Araucaria species of the Agathis shows relatively small interspecific differences 19 known species. All 13 are endemic to the islands amongst the extant 21 species. A subdivision into (Farjon 2001) and belong to the section Eutacta. Most sections, like in Araucaria, is far from being settled. of these species are adapted to ultramafic rocks and their Most of the species occur as scattered trees or as small derived soils (Jaffre´1995). Therefore it is suggested that groves within dense rainforests, usually as canopy there was a remarkable differentiation of new species emergents (Page 1990). In New Caledonia species nested in section Eutacta after the emplacement of the are limited mostly to maquis on ultramafic soils ultramafic rocks in the late Eocene (40–45 myr, Jaffre´ (Farjon 2001). The individual ecological and social 1995). In all other regions Araucaria has only one or two status of all Agathis species has been discussed in species (Farjon 2001). Ecological amplitude of Araucar- Whitmore and Page (1980) and in Enright and Hill ia is clearly wider than in Agathis. Araucaria occurs in (1995). Agathis is distinguished by petiolate leaves montane tropical to subtropical rainforests in Malesia, without a conspicuous midrib in opposite to suboppo- in maquis in New Caledonia and in temperate to cool site arrangement, wedge-shaped cone scales without any temperate mixed conifer–angiosperm forests up to the ARTICLE IN PRESS 260 L. Kunzmann / Zoologischer Anzeiger 246 (2007) 257–277 Fig. 4. Recent distribution of Araucaria Jussieu, 1789 (compiled from Farjon 2001; Enright and Hill 1995). timber line in the Andes in South America (Enright and Hill 1995). Araucaria shows relatively large interspecific differences amongst its extant 19 species. A subdivision into the four sections Araucaria, Bunya Wilde and Eames, 1952, Eutacta Endlicher, 1842 and Intermedia White, 1947 has been accepted widely. Most of the species occur as small groves or as local pure popula- tions in more mesic temperate habitats on tropical mountain flanks. They are usually canopy emergents (Page 1990). The individual ecological and social status of all Araucaria species has been discussed in Enright and Hill (1995). Araucaria is distinguished by non-petiolate spirally arranged leaves, cone scales with free ovuliferous tips Fig. 5. Recent distribution of Wollemia Jones et al., 1995. (ligulae) and large adnate seeds which are fused to the scale. Cone scales and seeds are shed as a complex