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[A] Capurodendron naciriae, C. andrafiamenae, [H-J] C. sakarivorum L.Gaut & Boluda, in Boluda, Christe, Naciri & Gautier, 2022. |
Abstract
The Malagasy genus Capurodendron currently accommodates 26 described species and is the largest genus of the family Sapotaceae in Madagascar. These species are frequently logged because of their valued hardwood, which potentially puts them at risk of extinction. Species-level identifications are often problematic, and this hinders both an accurate assessment of their conservation status and the development of effective protection measures. We sorted all the material (ca. 860 collections) available in the herbaria with significant collections for Madagascar into 47 putative species based on morphology. On 41 of these, for which we were able to retrieve suitable DNA, we conducted a phylogenetic reconstruction based on molecular sequences of 638 loci from 108 Capurodendron specimens, performing a target capture approach combined with next-generation sequencing. Maximum likelihood (RAxML), pseudocoalescence (ASTRAL), and coalescence (STACEY) analyses showed that Capurodendron comprises two deeply divergent lineages. One, which includes a single species, is here newly described as C. subg. Reflexisepala based on its distinctive morphology. The second lineage contains all remaining species, which seem to have resulted from a rapid radiation event. The phylogenetic tree provides good support for most of the species hypothesized based on morphology, with the exception of two species-groups that we have named the Arid Complex and the Eastern Complex. As many as 20 species-level lineages genetically distinct from any of the currently recognized species were identified, 17 of which were morphologically well-characterized, representing strong candidates for new species. This would suggest that Capurodendron is the most species-rich endemic genus of plants in Madagascar. While 14 of these 20 clades are still under study, we here describe six species new to science: Capurodendron andrafiamenae (provisionally assessed as CR), C. aubrevillei (VU), C. birkinshawii (CR), C. naciriae (EN), C. randrianaivoi (CR), and C. sakarivorum (EN). Capurodendron oblongifolium comb. nov. (EN), previously regarded as a variety of C. perrieri, represents a distinct lineage that is here recognized at the species level. The newly described species are illustrated by line drawings and photographs from the field, and a preliminary threat assessment is provided. We discuss the evolutionary history of Capurodendron and also explore the question of node age estimates and their methodological limitations.
Keywords: Capurodendron, Madagascar, NGS, new species, node age estimation, phylogenomics, Sapotaceae, target capture
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| Capurodendron andrafiamenae: A, Flower fascicles (Gautier 5395); B, Flower detail (Burivalova 138). C. aubrevillei: C, Twig showing Aubréville's branching pattern and thickened apices (Gautier 5544); D, Detail of the stipules among the petioles (Randriarisoa 125); E, Young leaves (Randriarisoa 125); F, Bark with a slash showing some latex and the external wood color (Gautier 6024). — Photos: A, C & F by Laurent Gautier; B by Zuzana Burivalova; D & E by Carlos G. Boluda. |
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| Capurodendron andrafiamenae. A, Flowering branch; B, Leaf (upper surface); C, Leaf (lower surface); D, Flower; E, Flower in longitudinal section; F, Outer side of a detached corolla spread and opened, with a lobe folded down showing a stamen; G, Inner side of a detached corolla spread and opened; H, Fruit; I, Lateral view of a seed; J, Ventral view of a seed. — Drawing: Gabriela Loza. |
Capurodendron Aubrév. in Adansonia, sér. 2, 2: 92. 1962.
Capurodendron subg. Reflexisepala Boluda & L.Gaut., subg. nov.
– Type: Capurodendron madagascariense (Lecomte) Aubrév.
(≡ Sideroxylon madagascariense Lecomte).
Capurodendron Aubrév. subg. Capurodendron
Capurodendron andrafiamenae L.Gaut & Boluda, sp. nov.
Diagnosis: Capurodendron andrafiamenae differs from the vegetatively most similar species C. greveanum by the young shoots and petioles covered by rusty trichomes (vs. green and glabrous in C. greveanum), the longer pedicels (7–11 vs. 5 mm), the longer sepals (4.5 vs. 3.5 mm), the longer corolla lobes (5.4 vs. 3 mm), and the glabrous (vs. pubescent) ovary.
Etymology: The specific epithet refers to the Andrafiamena forest, where the new species was found, now part of the Andrafiamena-Andavakoera protected area, managed by the NGO Fanamby.
Distribution, ecology and phenology: Capurodendron andrafiamenae is only known from the type locality in the north of Madagascar, in dense humid semi-deciduous forest on sandstone from 360 to 540 m asl (Fig. 7). The two collections have flowers and were collected in November and December, the earlier one also bearing fruit from the previous season's flowering.
Capurodendron aubrevillei L.Gaut & Boluda, sp. nov.
Diagnosis: Capurodendron aubrevillei differs from other Capurodendron species with marked Aubréville growth pattern and brachyblasts by its oblanceolate, almost glabrous and flat leaves (vs. pubescent and more or less bullate or with markedly raised secondaries on the lower surface in C. antongiliense, C. birkinshawii, C. schatzii, and C. nodosum).
Etymology: This species is dedicated to André Aubréville, professor at the Muséum National d'Histoire Naturelle in Paris, a famous and sagacious taxonomist of Sapotaceae, and author of the corresponding volume of the Flore de Madagascar et des Comores (Aubréville, 1974). The Aubréville growth pattern, dominant in the Sapotaceae family and particularly evident in this species, was also named in his honor (Hallé & al., 1978).
Distribution, ecology and phenology: Capurodendron aubrevillei is found in lowland moist evergreen forests, from the Masoala Peninsula southwards to Foulpointe, from ca. 80 to 400 m elevation (Fig. 7). This very distinctive species has been collected from November to February so far, but never in fertile condition.
Capurodendron birkinshawii L.Gaut & Boluda, sp. nov.
Diagnosis: Capurodendron birkinshawii resembles C. nodosum by the arrangement of its leaves at the apex of short brachyblasts, but differs by its glabrous ovary, the villous stamen filaments, larger stipules, its broadly rounded to subcordate leaf base (vs. obtuse), its bullate leaf lamina, and the higher number of secondary veins (12–14 vs. 8–12).
Etymology: This species honors Chris Birkinshaw, of the Missouri Botanical Garden's Madagascar Program, who collected the type specimen, in recognition of his dedication to the conservation of the Malagasy flora and the training of national botanists.
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| Capurodendron naciriae: A, Flower; B, Leaf; C, Fruit (Gautier 6036). C. oblongifolium: D, Branch with fruits (Randrianaivo 3349); E, Corolla being expulsed by the calyx contraction (Frank Rakotonasolo, not collected). C. randrianaivoi: F, Underside of a leaf with remains of a flower (Randriarisoa 25); G, Twig with mature and growing leaves (Randriarisoa 50). C. sakarivorum: H, Flowering branch (Nusbaumer 1510); I, Flower clusters (Ranirison 1095), J, Immature fruits (Nusbaumer 1902). — Photos: A–C by Laurent Gautier; D by Richard Randrianaivo; E by Frank Rakotonasolo; F & G by Aina Randriarisoa; H–J by Louis Nusbaumer. |
Capurodendron naciriae L.Gaut & Boluda, sp. nov.
Diagnosis: Capurodendron naciriae resembles C. ludiifolium in its vegetative characters, especially the size and venation pattern of its leaves. It differs however by its smaller fruits (15–18 × 9–11 vs. 28–38 × 15–21 mm) that are ovoid (vs. elliptic), its larger calyx lobes, at least at fruiting stage, and its distinctly petiolate leaves (vs. subsessile).
Etymology: This species is dedicated to our colleague and friend Yamama Naciri of the Conservatoire et Jardin botaniques de la Ville de Genève, who was part of the collecting team and is deeply involved in our present efforts to resolve Malagasy Sapotaceae taxonomy and systematics by providing invaluable knowledge in population genetics and molecular phylogeny.
Distribution, ecology and phenology: Capurodendron naciriae is only known from northern Madagascar from: the littoral dry forest on sand at Analabe, near Lac Sahaka; the dry deciduous forest of Bobankora and Bekaraoka, 20 km inland; and forest remnants a few kilometers northwest of Vohémar (Fig. 7). Flowers were observed from October to January, and fruit in November.
Capurodendron randrianaivoi L.Gaut & Boluda, sp. nov.
Diagnosis: Capurodendron randrianaivoi is vegetatively similar to C. sakarivorum, but differs by its leaf blade length/petiole length ratio of 7–14 (vs. 2–5), its secondary and tertiary veins that have the same green color as the lamina in living specimens (vs. pale green), its usually lower number of secondaries (5–11 vs. 9–13), its staminodes that are glabrous in the central part of their outer side (vs. pubescent), and its beaked fruit with ridges (vs. non-beaked and without ridges).
Etymology: It is a pleasure to dedicate this species to our colleague and friend Richard Randrianaivo, of the Missouri Botanical Garden's Madagascar Program, who was the first to collect the species in flower, in recognition of his extensive knowledge of Sapotaceae, and in appreciation of the many fine moments we shared while collecting Sapotaceae in the field.
Distribution, ecology and phenology: Capurodendron randrianaivoi is only known from the extreme north of Madagascar, in dry deciduous forest, including in littoral sites (Fig. 7). It flowers from December to February, and the only specimen in fruit was collected in December.
Capurodendron sakarivorum L.Gaut & Boluda, sp. nov.
Diagnosis: Capurodendron sakarivorum is vegetatively similar to C. ankaranense Aubrév., especially in leaf blade shape, dimension and venation, but differs by its stipules, which are lacking or scale-like, inconspicuous and pubescent (vs. linear, 2 mm long, and glabrescent), its shorter petiole (ratio leaf blade length/petiole length of 4.2–8 vs. 2–5), its villous sepals and pedicels (vs. glabrous or with rare scattered trichomes), and its staminodes with the outer side densely villous (vs. glabrous toward the middle).
Etymology: This species is named after the Malagasy word “sakarivo”, which means “blood brother” to honor Patrick Ranirison and Louis Nusbaumer, two former Ph.D. students at Antananarivo and Geneva Universities, respectively, who have both collected this new species. They worked hand in hand for three consecutive seasons in the forest fragments around the municipality of Daraina. They contributed greatly to our knowledge of the flora and vegetation of this area, and to the official recognition of the entire region as the Loky Manambato protected area. At the end of their field work together, they decided to sacralize their friendship through the traditional ceremony of becoming blood brothers.
Distribution, ecology and phenology: Capurodendron sakarivorum is only known from northern Madagascar, in the deciduous forests of the Loky-Manambato protected area (previously Daraina), on laterite or sands (Fig. 7). Flowering recorded from January to February, fruiting starting in January.
Capurodendron oblongifolium (Lecomte) L.Gaut. & Boluda, comb. & stat. nov.
Carlos G. Boluda, Camille Christe, Yamama Naciri and Laurent Gautier. 2022. A 638-gene Phylogeny supports the Recognition of Twice as many Species in the Malagasy Endemic Genus Capurodendron (Sapotaceae). TAXON. DOI: 10.1002/tax.12676
