Research Article |
Corresponding author: Tao Deng ( dengtao@mail.kib.ac.cn ) Corresponding author: Hang Sun ( hsun@mail.kib.ac.cn ) Academic editor: Stephen Boatwright
© 2020 Jun-Tong Chen, Dai-Gui Zhang, Zhen-Yu Lv, Xian-Han Huang, Peng-Ju Liu, Jia-Ning Yang, Jing-Yuan Yang, Komiljon Tojibaev, Tao Deng, Hang Sun.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Chen J-T, Zhang D-G, Lv Z-Y, Huang X-H, Liu P-J, Yang J-N, Yang J-Y, Tojibaev K, Deng T, Sun H (2020) Oxytropis shennongjiaensis (Fabaceae), a new species from Hubei, Central China. PhytoKeys 149: 117-128. https://doi.org/10.3897/phytokeys.149.49533
|
Here we describe Oxytropis shennongjiaensis, a new species of Fabaceae from Central China (Hubei Province). Morphologically, O. shennongjiaensis is closely similar to O. sitaipaiensis, O. melanocalyx and O. kansuensis, but differs in stem characters, with less conspicuous internodes; persistent herbaceous stipules; pale yellow to white corolla; and stipitate legumes, 3–5 mm with a long beak. Phylogenetic analysis, based on the internal transcribed spacers (ITS) and two chloroplast markers (trnL–F and psbA–trnH), also identified O. shennongjiaensis as a new species, which is consistent with our morphological analyses. Considering the morphological data and phylogenetic data presented here, we believe that this evidence satisfies the required diagnostic criteria to identify O. shennongjiaensis as a new species.
Shennongjia National Park, phylogeny, new species, Oxytropis shennongjiaensis
About 310 species of Oxytropis DC. have been described, mainly distributed in East and Central Asia, as well as Europe, Africa and North America (
China has a vast territory with a wide range of complex and diverse topographies and soils and covering several climate zones, which contribute to the wealth of Chinese botanical diversity (
After three years of observations of wild living plants, herbarium specimens and laboratory studies, we determined that the morphological characters of this entity were stable and did not match with any other species of Oxytropis known to us. Accordingly, combined with a molecular phylogenetic analysis, based on the internal transcribed spacers (ITS) and two chloroplast markers trnL–F and psbA–trnH, we determined that this entity was indeed a species new to science and, therefore, we describe it below as O. shennongjiaensis D.G. Zhang, J.T. Chen, T. Deng & H. Sun, sp. nov. As Oxytropis was first discovered in the mountains of Central China (Hubei Province), this new species is particularly valuable for further study of the origins, dispersal and current geographical distribution of the genus.
The specimens of Oxytropis shennongjiaensis were collected from Shennongjia National Park in Hubei Province. Morphological characters, recorded for the new species, were based on fresh flowering and fruiting material. Morphological comparisons of O. shennongjiaensis, with related taxa O. sitaipaiensis T. P. Wang ex C. W. Chang, O. melanocalyx Bunge and O. kansuensis Bunge, are provided in Table
Morphological comparisons of Oxytropis shennongjiaensis with related species.
Characters | O. shennongjiaensis | O. sitaipaiensis | O. melanocalyx | O. kansuensis |
Plant height | 10–15 cm tall | 10–13 cm tall | 5–17 cm tall | 12–40(–60) cm tall |
Branches | Stems with less conspicuous internodes, 3–15 cm long. | Stems with 2 or more conspicuous internodes. | Stems with (0 or)1–4 conspicuous internodes. | Stems with (3 or)4 or 5 conspicuous internodes. |
Stipules | Stipules ovate, 7–10 mm long, herbaceous and margin scarious. | Stipules narrowly triangular, 3–5 mm long, membranous. | Stipules ovate-triangular, herbaceous. | Stipules narrowly triangular, 5 mm long, herbaceous. |
Leaves | Leaves with sparsely subappressed white trichomes. | Leaves with sparsely white trichomes. | Leaves with sparse yellow, white and black long trichomes. | Leaves with glabrescent or sparsely spreading white villous. |
Racemes | Racemes rather lax, 3–6-flowered; peduncle 2.5–4.5 cm long. | Racemes rather lax, 3–5-flowered; peduncle 5–6 cm long. | Racemes compact, 3–10(–15)-flowered; peduncle 5.5–14 cm long. | Racemes compact, 3–15-flowered; peduncle 7–21(–30) cm long. |
Bracts | Bracts ovate, 6–8 mm long, membranous. | Bracts subulate, ca. 2 mm long, membranous. | Bracts longer than pedicels, membranous. | Bracts triangular, 6–7 mm long, membranous. |
Calyx | Calyx 9–11 × 2–4 mm; lobes subulate, 4–5 mm long. | Calyx ca. 4 × 3 mm; lobes linear, 2–3 mm long. | Calyx ca. 4–9 × 2–3.5 mm; lobes lanceolate-linear, 2.5–4.7 mm long. | Calyx 6.5–11.5 × 2–4 mm, lobes subulate, 2–8 mm long. |
Flowers | Corolla pale yellow to white; standard 16–18 mm long, lamina broadly ovate, 12–13 × 10–11 mm, apex emarginate to 2-lobed, margin lightly undulately entire or with irregular repand teeth; wings 12–15 mm long, lamina obovate; keel 15 mm long, beak 3 mm long. | Corolla purplish; standard ca. 11 × 3 mm, lamina elliptic; wings ca. 10 mm long, lamina oblong; keel ca. 9.5 mm long, beak ca. 1.5 mm long. | Corolla blue; standard 10 × 14 mm, lamina broadly ovate, apex rounded to 2-lobed; wings 7–11 mm long, apex rounded to emarginate; keel ca. 7–11 mm long, beak ca. 0.2–1.1 mm long. | Corolla yellow or pale yellow; standard 10–17 mm long, lamina ovate, apex emarginate; wings 8–15 mm long, lamina obovate; keel 8–13 mm long, beak 0.2–1 mm long. |
Legume | Legume stipitate; stipe 5–7 mm long; body 20–25 × 5–7 mm, erect, inflated and slightly flattened, sparsely white trichomes; beak 3–5 mm long. | Legume stipitate; stipe ca. 7 mm; body ca. 23 × 4 mm, inflated and slightly flattened, with dense white short trichomes; beak 3 mm long. | Legume sessile or with a stipe; body 15–20 × 7–12 mm, pendulous, inflated, with long trichomes. |
Legume shortly stipitate; stipe 1–1.5 mm; body 8–12 × 3–10.5 mm, inflated. |
Distribution | Hubei (Shennongjia National Park) | Shaanxi | Gansu, Qinghai, Shaanxi, Sichuan, Xinjiang, Xizang, Yunnan. | Gansu, Qinghai, Sichuan, Xizang |
Molecular analysis was performed, based on 35 samples from 34 species (incorporating one variety) belonging to 11 sections of Oxytropis and, as such, represents the most comprehensive phylogeny of Chinese Oxytropis undertaken to date. Astragalus daenensis daenensisBoissier and A. penetratus Maassoumi were chosen as outgroups, following
Phylogenetic relationships were assessed using Bayesian Inference (BI) analyses, maximum parsimony (MP) and maximum likelihood (ML). A MP phylogenetic tree was constructed using PAUP* version 4.0a (
China. Hubei: Shennongjia National Park, 31°26'39.96"N, 110°16'00.34"E, 2880 m elev., 9 June 2019, D.G. Zhang & Q. Liu 19060901 (holo: KUN barcode 1347953!; iso: JIU!).
Compared with the published species of Oxytropis in China, O. shennongjiaensis appears to be closely similar to O. sitaipaiensis, from which it can be distinguished by its stems with less conspicuous internodes and 5–15 mm internodes (stems with two or more conspicuous internodes in O. sitaipaiensis); stipules ovate, 7–10 mm long, herbaceous (stipules narrowly triangular, 3–5 mm long, membranous in O. sitaipaiensis); bracts ovate, 6–8 mm long (bracts subulate, ca. 2 mm long in O. sitaipaiensis); calyx 9–11 × 2–4 mm (calyx ca. 4 × 3 mm in O. sitaipaiensis); pale yellow to white corolla; beak 3 mm long (purplish corolla; beak ca. 1.5 mm long in O. sitaipaiensis). Table
Perennial herbs, 10–15 cm tall. Yellowish-brown, cylindrical roots, up to 25 cm long, with lateral roots. Caulescent from a multi-headed caudex, slightly subterranean sometimes rhizomatous. Stems sprawling, 3–15 cm long, basally with persistent stipules; nodes of stems slightly swollen; internodes 5–15 mm long, invested with sparse, white trichomes. Leaves (4–) 6–9 (–11) cm long, 13–17 (–19)-foliolate; leaflets ovate, 5–11 × 2–4 mm, apex acuminate, with sparse, subappressed white trichomes, abaxially mid-vein slightly raised (obvious after drying), with denser trichomes along vein; dark purplish-red or green rachis, with sparse white trichomes; stipules ovate, 7–10 × 3–4 mm, herbaceous, basally connate, apex acuminate, abaxially sparsely hairy with white trichomes, adaxially glabrous, margins scarious, ciliate with black and white trichomes. Racemes rather lax, 3–6-flowered; peduncles 2.5–4.5 cm long, erect, villous, with white trichomes, sparsely intermixed with black trichomes below, with densely black trichomes above. Bracts ovate, 6–8 × 2–3 mm, membranous, with sparse, dark brown trichomes intermixed with white trichomes abaxially. Calyx campanulate, 9–11 × 2–4 mm, with dark brown trichomes sparsely intermixed with white trichomes outside; lobes subulate, 4–5 mm long, as long as or sometimes slightly shorter than tube. Pale yellow to white corolla; standard 16–18 mm long, lamina broadly ovate, 12–13 × 10–11 mm, apex emarginate to 2-lobed, margins slightly undulated entire or with irregular repand teeth; wings 12–15 mm, lamina obovate, 7 × 4 mm long, apex obtuse, claw 4–5 mm long; keel 15 mm long, beak 3 mm long. Ovary linear, with dense white trichomes. Legumes stipitate (stipe 5–7 mm long), oblong-ellipsoid, 20–25 × 5–7 mm, erect, inflated and slightly flattened, with sparsely white trichomes, beak 3–5 mm long.
Flowering from May–June and fruiting from July–August.
The specific epithet refers to the Shennongjia National Park to which the species is endemic. The Chinese name is 神农架棘豆, shén nóng jià jí dòu in Chinese phonetic transcription.
The new species is currently known only from the Shennongjia National Park (Figure
The new species was only discovered in Jinsiyanya, Shennongjia National Park, from our expeditions during the past few years. About 300 individuals were observed and the extent of occurrence is ca. 50,000 m2. The precise conservation status of the population(s) has not been determined, so further explorations are needed to assess its conservation status. Based on available data, the new species is assigned to the category ‘Data Deficient’ (DD) of International Union for Conservation of Nature (IUCN 2019).
Based on the combined datasets (ITS, trnL–F and psbA–trnH), BI, MP and ML trees were reconstructed and their topologies are quite similar. The ML tree is presented in Figure
Maximum likelihood consensus tree of Oxytropis shennongjiaensis and related taxa. Numbers above branches indicate Bayesian posterior probability [PP], numbers below branches represent maximum likelihood bootstrap support [ML/BS] and maximum parsimony bootstrap support [MP/BS] values. Only bootstrap values > 50% are shown. The new species is shown in bold.
These above-detailed characters indicate that, according to
Phylogenetic analyses, based on 35 samples from 34 species (incorporating one variety), show that their topologies of the BI, MP and ML trees were quite similar and were consistent with previous studies (
Considering the morphological data and phylogenetic results, we believe that this evidence satisfies the required diagnostic criteria to identify O. shennongjiaensis as a new species.
We are grateful to Ms. Song Min-Shu for her valuable experimental guidance, to Dr. Bruce Maslin and Dr. Zhang Jian-Wen for revising the manuscript. This study was supported by grants from the Major Program on Technology Innovation of Hubei Province (2018ACA132), Hubei Key Laboratory of Shennongjia Snub-nosed Monkey Conservation Fund (2018SNJ0009), National Natural Science Foundation of China (31670206), National Natural Science Foundation of China-Yunnan joint fund to support key projects (U1802232), the Strategic Priority Research Program of Chinese Academy of Sciences (XDA20050203), National Key R & D Program of China (2017YFC0505200), Major Program of the National Natural Science Foundation of China (31590823), National Natural Science Foundation of China (31700165), Youth Innovation Promotion Association of the Chinese Academy of Sciences (2019382), Young Academic and Technical Leader Raising Foundation of Yunnan Province (2019HB039) and the Chinese Academy of Sciences “Light of West China” Program. We thank TopEdit (www.topeditsci.com) for its linguistic assistance during the preparation of this manuscript.
List of taxa used in the phylogenetic analysis of GenBank accession numbers (ITS / trnL–F / psbA–trnH).
Species | ITS | trnL–F | psbA–trnH |
Oxytropis shennongjiaensis | MT326210 | MT325864 | MT325865 |
Oxytropis aciphylla | GQ422810 | JX878501 | KF011559 |
Oxytropis ambigua | – | LN898539 | LN898577 |
Oxytropis anertii | EF685971 | – | – |
Oxytropis avisoides | LC213314 | – | – |
Oxytropis bicolor | HQ199317 | – | – |
Oxytropis caerulea | HQ199316 | – | GU396771 |
Oxytropis chionobia | LC213335 | LC213480 | – |
Oxytropis ciliata | HQ199323 | KC936889 | KF011560 |
Oxytropis densa | LC213347 | LC213486 | – |
Oxytropis falcata | KJ143722 | – | – |
Oxytropis filiformis | HQ199321 | LN898596 | LN898483 |
Oxytropis giraldii | LC213352 | LC213491 | – |
Oxytropis glabra | LC213354 | LC213492 | LT856572 |
Oxytropis glabra var. tenuis | GQ422805 | KC936891 | KF011569 |
Oxytropis grandiflora | HQ199315 | – | – |
Oxytropis hirta | LC213363 | LC213496 | – |
Oxytropis immersa | LC213366 | – | – |
Oxytropis inschanica | HQ199322 | JX893502 | KF011571 |
Oxytropis kansuensis | KJ143724 | – | – |
Oxytropis lapponica | LC213388 | – | – |
Oxytropis latibracteata | LC213389 | – | – |
Oxytropis leptophylla | – | JX893503 | KF011572 |
Oxytropis melanocalyx | LC213397 | LC213519 | – |
Oxytropis merkensis | LC213398 | LC213520 | – |
Oxytropis microphylla | KP338205 | – | KP338460 |
Oxytropis ochrantha | GQ422819 | JX893489 | KF011574 |
Oxytropis ochrocephala | LC213409 | – | – |
Oxytropis pilosa | KM053396 | LN898607 | LN898495 |
Oxytropis racemosa | HQ199320 | JX893508 | GU396818 |
Oxytropis sericopetala | KJ143725 | – | – |
Oxytropis squammulosa | HQ199318 | JX893509 | KF011579 |
Oxytropis verticillaris | GQ422815 | JX893514 | KF011581 |
Astragalus daenensis | AB051963 | – | – |
Astragalus penetratus | AB231100 | – | – |