Agathis (Araucariaceae) is a genus of broadleaved conifers that today inhabits lowland to upper montane rainforests of Australasia and Southeast Asia. A previous report showed that the earliest known fossils of the genus, from the early Paleogene and possibly latest Cretaceous of Patagonian Argentina, host diverse assemblages of insect and fungal associations, including distinctive leaf mines. Here, we provide complete documentation of the fossilized Agathis herbivore communities from Cretaceous to Recent, describing and comparing insect and fungal damage on Agathis across four latest Cretaceous to early Paleogene time slices in Patagonia with that on 15 extant species. Notable fossil associations include various types of external foliage feeding, leaf mines, galls, and a rust fungus. In addition, enigmatic structures, possibly armored scale insect (Diaspididae) covers or galls, occur on Agathis over a 16-million-year period in the early Paleogene. The extant Agathis species, throughout the range of the genus, are associated with a diverse array of mostly undescribed damage similar to the fossils, demonstrating the importance of Agathis as a host of diverse insect herbivores and pathogens and their little-known evolutionary history.
Keywords
Araucariaceae, Gondwana, herbivory, plant-insect associations
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Persistent biotic interactions of a Gondwanan conifer from Cretaceous Patagonia to modern Malesia
Many plant genera in the tropical West Pacific are survivors from the paleo-rainforests of Gondwana. For example, the oldest fossils of the Malesian and Australasian conifer
- Award ID(s):
- 1925755
- NSF-PAR ID:
- 10360618
- Publisher / Repository:
- Nature Publishing Group
- Date Published:
- Journal Name:
- Communications Biology
- Volume:
- 3
- Issue:
- 1
- ISSN:
- 2399-3642
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Agathis (Araucariaceae) is a genus of broadleaved conifers that today inhabits lowland to upper montane rainforests of Australasia and Southeast Asia. A previous report showed that the earliest known fossils of the genus, from the early Paleogene and possibly latest Cretaceous of Patagonian Argentina, host diverse assemblages of insect and fungal associations, including distinctive leaf mines. Here, we provide complete documentation of the fossilized Agathis herbivore communities from Cretaceous to Recent, describing and comparing insect and fungal damage on Agathis across four latest Cretaceous to early Paleogene time slices in Patagonia with that on 15 extant species. Notable fossil associations include various types of external foliage feeding, leaf mines, galls, and a rust fungus. In addition, enigmatic structures, possibly armored scale insect (Diaspididae) covers or galls, occur on Agathis over a 16-million-year period in the early Paleogene. The extant Agathis species, throughout the range of the genus, are associated with a diverse array of mostly undescribed damage similar to the fossils, demonstrating the importance of Agathis as a host of diverse insect herbivores and pathogens and their little-known evolutionary history.more » « less
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Abstract Chalcidoidea are mostly parasitoid wasps that include as many as 500 000 estimated species. Capturing phylogenetic signal from such a massive radiation can be daunting. Chalcidoidea is an excellent example of a hyperdiverse group that has remained recalcitrant to phylogenetic resolution. We combined 1007 exons obtained with Anchored Hybrid Enrichment with 1048 ultra‐conserved elements (UCEs) for 433 taxa including all extant families, >95% of all subfamilies, and 356 genera chosen to represent the vast diversity of the superfamily. Going back and forth between the molecular results and our collective knowledge of morphology and biology, we detected bias in the analyses that was driven by the saturation of nucleotide data. Our final results are based on a concatenated analysis of the least saturated exons and UCE datasets (2054 loci, 284 106 sites). Our analyses support an expected sister relationship with Mymarommatoidea. Seven previously recognized families were not monophyletic, so support for a new classification is discussed. Natural history in some cases would appear to be more informative than morphology, as illustrated by the elucidation of a clade of plant gall associates and a clade of taxa with planidial first‐instar larvae. The phylogeny suggests a transition from smaller soft‐bodied wasps to larger and more heavily sclerotized wasps, with egg parasitism as potentially ancestral for the entire superfamily. Deep divergences in Chalcidoidea coincide with an increase in insect families in the fossil record, and an early shift to phytophagy corresponds with the beginning of the “Angiosperm Terrestrial Revolution”. Our dating analyses suggest a middle Jurassic origin of 174 Ma (167.3–180.5 Ma) and a crown age of 162.2 Ma (153.9–169.8 Ma) for Chalcidoidea. During the Cretaceous, Chalcidoidea may have undergone a rapid radiation in southern Gondwana with subsequent dispersals to the Northern Hemisphere. This scenario is discussed with regard to knowledge about the host taxa of chalcid wasps, their fossil record and Earth's palaeogeographic history.
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Abstract Background The Chloranthaceae comprise four extant genera (Hedyosmum, Ascarina, Chloranthus and Sarcandra), all with simple flowers. Molecular phylogenetics indicates that the Chloranthaceae diverged very early in angiosperm evolution, although how they are related to eudicots, magnoliids, monocots and Ceratophyllum is uncertain. Fossil pollen similar to that of Ascarina and Hedyosmum has long been recognized in the Early Cretaceous, but over the last four decades evidence of extinct Chloranthaceae based on other types of fossils has expanded dramatically and contributes significantly to understanding the evolution of the family.
Scope Studies of fossils from the Cretaceous, especially mesofossils of Early Cretaceous age from Portugal and eastern North America, recognized diverse flowers, fruits, seeds, staminate inflorescences and stamens of extinct chloranthoids. These early chloranthoids include forms related to extant Hedyosmum and also to the Ascarina, Chloranthus and Sarcandra clade. In the Late Cretaceous there are several occurrences of distinctive fossil androecia related to extant Chloranthus. The rich and still expanding Cretaceous record of Chloranthaceae contrasts with a very sparse Cenozoic record, emphasizing that the four extant genera are likely to be relictual, although speciation within the genera might have occurred in relatively recent times. In this study, we describe three new genera of Early Cretaceous chloranthoids and summarize current knowledge on the extinct diversity of the group.
Conclusions The evolutionary lineage that includes extant Chloranthaceae is diverse and abundantly represented in Early Cretaceous mesofossil floras that provide some of the earliest evidence of angiosperm reproductive structures. Extinct chloranthoids, some of which are clearly in the Chloranthaceae crown group, fill some of the morphological gaps that currently separate the extant genera, help to illuminate how some of the unusual features of extant Chloranthaceae evolved and suggest that Chloranthaceae are of disproportionate importance for a more refined understanding of ecology and phylogeny of early angiosperm diversification.
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Fossil evidence from South America for the diversification of Cunoniaceae by the earliest Palaeocenenull (Ed.)Abstract Background and Aims Cunoniaceae are woody plants with a distribution that suggests a complex history of Gondwanan vicariance, long-distance dispersal, diversification and extinction. Only four out of ~27 genera in Cunoniaceae are native to South America today, but the discovery of extinct species from Argentine Patagonia is providing new information about the history of this family in South America. Methods We describe fossil flowers collected from early Danian (early Palaeocene, ~64 Mya) deposits of the Salamanca Formation. We compare them with similar flowers from extant and extinct species using published literature and herbarium specimens. We used simultaneous analysis of morphology and available chloroplast DNA sequences (trnL–F, rbcL, matK, trnH–psbA) to determine the probable relationship of these fossils to living Cunoniaceae and the co-occurring fossil species Lacinipetalum spectabilum. Key Results Cunoniantha bicarpellata gen. et sp. nov. is the second species of Cunoniaceae to be recognized among the flowers preserved in the Salamanca Formation. Cunoniantha flowers are pentamerous and complete, the anthers contain in situ pollen, and the gynoecium is bicarpellate and syncarpous with two free styles. Phylogenetic analysis indicates that Cunoniantha belongs to crown-group Cunoniaceae among the core Cunoniaceae clade, although it does not have obvious affinity with any tribe. Lacinipetalum spectabilum, also from the Salamanca Formation, belongs to the Cunoniaceae crown group as well, but close to tribe Schizomerieae. Conclusions Our findings highlight the importance of West Gondwana in the evolution of Cunoniaceae during the early Palaeogene. The co-occurrence of C. bicarpellata and L. spectabilum, belonging to different clades within Cunoniaceae, indicates that the diversification of crown-group Cunoniaceae was under way by 64 Mya.more » « less
