Markus Ruhsam1, Alexandra Clark2, Aline Finger2, Adrien S Wulff3, Robert R Mill2, Philip I Thomas2, Martin F Gardner2, Myriam Gaudeul4, Richard A Ennos5, Peter M Hollingsworth2. 1. Royal Botanic Garden Edinburgh, 20A Inverleith Row, Edinburgh, EH3 5LR, UK m.ruhsam@rbge.ac.uk. 2. Royal Botanic Garden Edinburgh, 20A Inverleith Row, Edinburgh, EH3 5LR, UK. 3. SoREco-NC, 57 Route de l'Anse Vata 98800 Nouméa, New Caledonia Institut Agronomique néo-Calédonien (IAC), Axe II "Diversités biologique et fonctionnelle des écosystèmes, BP 73 98890 Païta, New Caledonia. 4. Institut de Systématique, Évolution, Biodiversité (ISYEB), UMR 7205 CNRS MNHN UPMC EPHE, Muséum national d'Histoire naturelle, Sorbonne Universités, 57 rue Cuvier, CP39, F-75005 Paris, France. 5. University of Edinburgh, Institute of Evolutionary Biology, West Mains Road, Edinburgh, EH3 9JT, UK.
Abstract
PREMISE OF THE STUDY: Cryptic species represent a conservation challenge, because distributions and threats cannot be accurately assessed until species are recognized and defined. Cryptic species are common in diminutive and morphologically simple organisms, but are rare in charismatic and/or highly visible groups such as conifers. New Caledonia, a small island in the southern Pacific is a hotspot of diversity for the emblematic conifer genus Araucaria (Araucariaceae, Monkey Puzzle trees) where 13 of the 19 recognized species are endemic. METHODS: We sampled across the entire geographical distribution of two closely related species (Araucaria rulei and A. muelleri) and screened them for genetic variation at 12 nuclear and 14 plastid microsatellites and one plastid minisatellite; a subset of the samples was also examined using leaf morphometrics. KEY RESULTS: The genetic data show that populations of the endangered A. muelleri fall into two clearly distinct genetic groups: one corresponding to montane populations, the other corresponding to trees from lower elevation populations from around the Goro plateau. These Goro plateau populations are more closely related to A. rulei, but are sufficiently genetically and morphological distinct to warrant recognition as a new species. CONCLUSIONS: Our study shows the presence of a previously unrecognized species in this flagship group, and that A. muelleri has 30% fewer individuals than previously thought. Combined, this clarification of species diversity and distributions provides important information to aid conservation planning for New Caledonian Araucaria.
PREMISE OF THE STUDY: Cryptic species represent a conservation challenge, because distributions and threats cannot be accurately assessed until species are recognized and defined. Cryptic species are common in diminutive and morphologically simple organisms, but are rare in charismatic and/or highly visible groups such as conifers. New Caledonia, a small island in the southern Pacific is a hotspot of diversity for the emblematic conifer genus Araucaria (Araucariaceae, Monkey Puzzle trees) where 13 of the 19 recognized species are endemic. METHODS: We sampled across the entire geographical distribution of two closely related species (Araucaria rulei and A. muelleri) and screened them for genetic variation at 12 nuclear and 14 plastid microsatellites and one plastid minisatellite; a subset of the samples was also examined using leaf morphometrics. KEY RESULTS: The genetic data show that populations of the endangered A. muelleri fall into two clearly distinct genetic groups: one corresponding to montane populations, the other corresponding to trees from lower elevation populations from around the Goro plateau. These Goro plateau populations are more closely related to A. rulei, but are sufficiently genetically and morphological distinct to warrant recognition as a new species. CONCLUSIONS: Our study shows the presence of a previously unrecognized species in this flagship group, and that A. muelleri has 30% fewer individuals than previously thought. Combined, this clarification of species diversity and distributions provides important information to aid conservation planning for New Caledonian Araucaria.
Authors: Ya-Dan Yan; Xin-Yu Li; James R P Worth; Xue-Ying Lin; Markus Ruhsam; Lu Chen; Xing-Tong Wu; Min-Qiu Wang; Philip I Thomas; Ya-Feng Wen Journal: Appl Plant Sci Date: 2019-07-17 Impact factor: 1.936