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Evolution and loss of long-fringed petals: A case study using a dated phylogeny of the snake gourds, Trichosanthes (Cucurbitaceae)
Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Systematic Biology. (Ethnobotany)
Harvard University, Department of Organismic and Evolutionary Biology.
Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Systematic Biology.
University of Munich (LMU), Systematic Botany and Mycology.
2012 (English)In: BMC Evolutionary Biology, ISSN 1471-2148, Vol. 12, 108- p.Article in journal (Refereed) Published
Abstract [en]


The Cucurbitaceae genus Trichosanthes comprises 90–100 species that occur from India to Japan and southeast to Australia and Fiji. Most species have large white or pale yellow petals with conspicuously fringed margins, the fringes sometimes several cm long. Pollination is usually by hawkmoths. Previous molecular data for a small number of species suggested that a monophyletic Trichosanthes might include the Asian genera Gymnopetalum (four species, lacking long petal fringes) and Hodgsonia (two species with petals fringed). Here we test these groups’ relationships using a species sampling of c. 60% and 4759 nucleotides of nuclear and plastid DNA. To infer the time and direction of the geographic expansion of the Trichosanthes clade we employ molecular clock dating and statistical biogeographic reconstruction, and we also address the gain or loss of petal fringes.


Trichosanthes is monophyletic as long as it includes Gymnopetalum, which itself is polyphyletic. The closest relative of Trichosanthes appears to be the sponge gourds, Luffa, while Hodgsonia is more distantly related. Of six morphology-based sections in Trichosanthes with more than one species, three are supported by the molecular results; two new sections appear warranted. Molecular dating and biogeographic analyses suggest an Oligocene origin of Trichosanthes in Eurasia or East Asia, followed by diversification and spread throughout the Malesian biogeographic region and into the Australian continent.


Long-fringed corollas evolved independently in Hodgsonia and Trichosanthes, followed by two losses in the latter coincident with shifts to other pollinators but not with long-distance dispersal events. Together with the Caribbean Linnaeosicyos, the Madagascan Ampelosicyos and the tropical African Telfairia, these cucurbit lineages represent an ideal system for more detailed studies of the evolution and function of petal fringes in plant-pollinator mutualisms.

Place, publisher, year, edition, pages
2012. Vol. 12, 108- p.
National Category
Biological Systematics
Research subject
Biology with specialization in Systematics
URN: urn:nbn:se:uu:diva-167012DOI: 10.1186/1471-2148-12-108ISI: 000312133600001OAI: diva2:499657
Available from: 2012-02-13 Created: 2012-01-19 Last updated: 2013-06-12Bibliographically approved
In thesis
1. Snake Gourds, Parasites and Mother Roasting: Medicinal plants, plant repellents, and Trichosanthes (Cucurbitaceae) in Lao PDR
Open this publication in new window or tab >>Snake Gourds, Parasites and Mother Roasting: Medicinal plants, plant repellents, and Trichosanthes (Cucurbitaceae) in Lao PDR
2012 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Background. Traditional plant use was studied in Lao PDR. Research focused on medicinal plant use by the Brou, Saek and Kry ethnic groups, traditional plant repellents against parasitic arthropods and leeches, and the phylogeny and biogeography of the medicinally-important snake gourd genus (Trichosanthes, Cucurbitaceae).  Methods. The ethnobiology research used a combination of structured interviews, village surveys, botanical collecting, hydro-distillation, GC-MS analysis, literature studies, and laboratory experiments. The plant systematics research used a combination of morphological studies, molecular biology laboratory work, and phylogenetic, dating and biogeographical analysis.  Results. Informants reported the use of close to 100 species to repel arthropods and leeches, many of which have constituents with documented efficacy.  Brou, Saek and Kry informants use over 75 plant species for women’s healthcare, mainly during the postpartum period for steam sauna, steam bath, hotbed, mother roasting, medicinal decoctions and infusions, and postpartum diet.  A molecular phylogeny of Trichosanthes and Gymnopetalum using a broad sampling of ~60% of their species and 4756 nucleotides of nuclear and plastid DNA shows that Gymnopetalum is nested within Trichosanthes. Fossil-calibrated Bayesian molecular dating of the Trichosanthes phylogeny reveals an early Oligocene origin of the genus, and many of the extant sections originating and diversifying during the Miocene. Biogeographical analysis shows a likely East or South Asian origin of Trichosanthes, with lineages diversifying and spreading throughout Australasia from the early Pliocene to the Pleistocene.  Discussion. Traditional plant use in Lao PDR is common and widespread. The presence among the repellent species of economical alternatives to costly synthetic repellents is tenable, and the subject of ongoing studies.  Postpartum traditions and medicinal plant use are essential parts of childbirth and postpartum recovery in these ethnic groups, and many other groups in Lao PDR. Efforts to improve maternal healthcare and reduce maternal and infant mortality need to integrate these traditions with modern notions of healthcare to achieve wider adoption. Documenting all possible uses of commonly used medicinal plant species shows that similarity in use between these ethnic groups is relatively low considering that they share, and have shared for many generations, the same environment and resources. A lack of effective cures leads to a process of continuous innovation, where effective cures are shared between cultures, but remedies of only cultural importance, or those under evaluation are culture-specific.  The Trichosanthes phylogeny implies the merging of Gymnopetalum into Trichosanthes, and this is done using available names or new combinations. A synopsis of Trichosanthes, the new combinations, and a revision of the species in Australia, are made and presented.  Conclusions. Traditional plant use is widespread in Lao PDR, and of significance to many people as a source of primary healthcare and inexpensive repellents. The important medicinal plant genus Trichosanthes includes Gymnopetalum, and has a complex biogeographic history with multiple colonization events of Australasia.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2012. 59 p.
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 901
Trichosanthes, Ethnobotany, Similarity of Knowledge, Biogeography, Molecular Dating, Brou, Saek, Kry, Mother roasting, Postpartum healthcare, Parturition, Childbirth, Traditional Medicine, Plant repellents, Fermented fish
National Category
Biological Sciences
Research subject
Biology with specialization in Systematics
urn:nbn:se:uu:diva-168536 (URN)978-91-554-8281-7 (ISBN)
Public defence
2012-03-30, Lindahlsalen, Norbyvägen 18, Uppsala, 13:00 (English)
Available from: 2012-03-02 Created: 2012-02-13 Last updated: 2012-03-29Bibliographically approved

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