REINWARDTIA Vol. 21. No. 1. pp: 35‒40 DOI: 10.55981/reinwardtia.v21i1.4374 35 A NEW SPECIES OF MUKIA (CUCURBITACEAE) FROM SUMBA ISLAND, INDONESIA Received January 28, 2021; accepted June 6, 2022 MENTARI PUTRI PRATAMI Plant Biology Graduate Program, Department of Biology, Faculty of Mathematics and Natural Sciences, IPB University, Bogor 16680 Indonesia. (now in Department of Biology, Universitas Pertahanan Indonesia. Kampus Universitas Pertahanan, Sentul, Bogor 16810, Indonesia. Email: mentari.pratami@idu.ac.id TATIK CHIKMAWATI Department of Biology, Faculty of Mathematics and Natural Sciences, IPB University, Bogor 16680, Indonesia. Email: tchikmawati@yahoo.com RUGAYAH Herbarium Bogoriense, Research Center for Biosystematics and Evolution, National Research and Innovation Agency/Badan Riset dan Inovasi Nasional (BRIN), Cibinong Science Center, Jln. Raya Jakarta Bogor Km. 46, Cibinong 16911, Bogor, Indonesia. Email: titikrugayah@yahoo.com ABSTRACT PRATAMI, M. P., CHIKMAWATI, T. & RUGAYAH. 2022. A new species of Mukia (Cucurbitaceae) from Sumba Island, Indonesia. Reinwardtia 21(1): 35‒40. — Mukia sumbensis Pratami is described and illustrated as well as compared with its closely related species M. maderaspatana (L.) M.Roem. and M. leiosperma (Wight & Arn.) Wight. It differs in its tendril size, stem diameter, petiole hairiness, midrib indumentum on upper leaf surface, as well as in shape, margin, and surface of seed. Anatomically the leaf of the new species has two palisade layers, unlike the other two species which have only one layer. Key words: Cucur bitaceae, M uk ia, new species, Sumba. ABSTRAK PRATAMI, M. P., CHIKMAWATI, T. & RUGAYAH. 2022. Jenis baru Mukia (Cucurbitaceae) dari Pulau Sumba, Indonesia. Reinwardtia 21(1): 35‒40. — Mukia sumbensis Pratami dipertelakan dan dibuat ilustrasinya. Jenis tersebut berkerabat dekat dengan M. maderaspatana (L.) M.Roem. dan M. leiosperma (Wight & Arn.) Wight tetapi berbeda pada ukuran sulur, diameter batang, rambut pada tangkai daun, dan juga pada ibu tulang daun, serta bentuk, ukuran, tepi, dan permukaan biji. Secara anatomi jenis baru ini memiliki dua lapisan palisade, tidak seperti dua jenis lainnya yang hanya memiliki satu lapis. Kata kunci: Cucur bitaceae, jenis bar u, M uk ia, Su mba. INTRODUCTION Mukia Arn. is a cucurbitaceous genus of nine species distributed in Africa, South Asia, South- East Asia, and Australia (de Wilde & Duyfjes, 2010). The genus was firstly published by Arnott (1840), with one species M. scabrella (L.) Arn. as type species (now M. maderaspatana (L.) M.Roem.). In Australia, Telford (1982), enumerated six species, two of them M. maderaspatana (L.) M.Roem and M. micrantha (F.Muell.) F.Muell [now, A ustrobryonia micrantha (F.Muell.) I. Telford] were widespread and polymorphic, while the other species were not validly published (Schaefer et al., 2008). As many as six species have been recorded in Asia by de Wilde & Duyfjes (2006), namely Mukia gracilis (Kurz) W.J.de Wilde & Duyfjes, M. rumphiana (Scheff.) W.J.de Wilde & Duyfjes, M. ritchiei (C.B.Clarke) W.J.de Wilde & Duyfjes, M. javanica (Miq.) C.Jeffrey, M. leiosperma (Wight & Arn.) Wight, and M. maderaspatana (L.) M.Roem. Based on molecular data, the Asian species were found to be nested within the Cucumis (Schaefer, 2007; Renner et al., 2007; Ghebretinsae et al., 2007a; Telford et al., 2011). Therefore, they transferred all of them to Cucumis (Ghebretinsae et al., 2007b). Nevertheless, in revising the Malesian Cucurbitaceae, de Wilde & Duyfjes (2010) continued to recognize Mukia as distinct from Cucumis. Pratami et al. (2019) found further seven seed characters (colour, shape, size, surface pattern, seed edge, transverse section at seed neck, and the markings of the inner seed coat surfaces), it supported de Wilde & Duyfjes in separating Mukia from Cucumis. Further molecular analysis on this group by Pratami et al. (2020) showed that, ISSR http://dx.doi.org/10.14203/reinwardtia.v19i1.3850 REINWARDTIA 36 [VOL.21 markers can be used to distinguish Cucumis and Mukia as separate genera. In working out all specimens of Mukia deposited in Herbarium Bogoriense (BO), there is one specimen Iboet 497 from Sumba which has different characteristics from the other species of Mukia. Previously, de Wilde & Duyfjes have already noted on the specimen sheet that it has hairy petiole and different seed edges, which differ from M. maderaspatana. Therefore, we decided to do further observations on this specimen as well as on M. leiosperma. MATERIALS AND METHODS Morphological observations were carried out on all specimens of Mukia – in all numbering 285 sheets – deposited in Herbarium Bogoriense (BO) and in National Herbarium of the Netherlands (virtual herbarium). Leaf anatomical preparations of Iboet 497 herbarium specimen, has been made at the Laboratory of Ecology and Plant Resources, Department of Biology, IPB University, by making paradermal and transversal sections using Sass methods (1951). For the M. maderaspatana we used specimens MPP 24, MPP 25, and MPP 55, while for M. leiosperma specimens Sauliere 68 and Sauliere 142 were used. RESULTS AND DISCUSSION The results of our morphological observations on Iboet 497, showed that if it compared with M. maderaspatana it has bigger stem diameter, thicker tendril, retrorse indumentum on petiole, bigger indumentum on midrib, and pitted surface of its seed. Comparison with M. leiosperma showed that Iboet 497 has similar shape, size, and colour of fruit characters, but it has thinner tendril, smaller seeds which have smooth surface (Table 1). Table 1 as well as the accompanying Fig. 2 and Fig. 3 also summarises the results of our anatomical observations of the three species. It shows that the transversal leaf section has two layers of palisade tissue of Iboet 497. Mukia sumbensis Pr atami spec. nov. — TYPE: INDONESIA, Sumba, Taimanga, Kenangar, 15 Mei 1925, Iboet 497 (holotype BO!, isotype L [photo!]). Figs. 1–3. Morphologically the new species is closely related to M. maderaspatana but it has bigger stem Table 1. Characters differences of M. maderaspatana, M. sumbensis, and M. leiosperma No Character states M. maderaspatana M. sumbensis M. leiosperma 1 Stem diameter 0.4–1.4 mm 1.8–1.9 mm 0.8–1.2 mm 2 Tendril Thin (0.1 mm) Thick (0.2 mm) Thin (0.1 mm) 3 Indumentum types of petiole Scabrous and hispid Retrorse Villous 4 Midrib indumentum size on upper leaf surface Uniform Not uniform Uniform 5 Indumentum colour Whitish, not shiny Whitish, not shiny Golden, shiny 6 Seed shape Broadly ovate Ovate Ovate 7 Average seed size 4.27 × 3.16 mm 4.31 × 2.96 mm 5.50 × 3.40 mm 8 Seed surface Convex and irregularly papillate Convex and pitted or nearby smooth Flat and smooth 9 Stomata in adaxial surface Present Absent Absent 10 Size of stomata 19.70 × 11.31 μm 61.86 × 42.17 μm 21.92 × 14.21 μm 11 Size of epidermal cells 31.89 × 21.41 μm 159.15 × 105.40 μm 56.60 μm × 31.14 μm 12 Palisade layer One Two One PRATAMI et al.: A new species of Mukia (Cucurbitaceae) 2022] 37 Fig. 1. Mukia sumbensis Pratami spec. nov. A. Habit, climbing stem. B. Petiole. C. Leaves adaxial. D–E. Leaves abaxial. F. Fruit. G. Seed. H. Seed edge. Scale bar = 1 mm. From Iboet 497. Drawn by W. A. Mustaqim. REINWARDTIA 38 [VOL.21 B2 B1 A1 A2 C1 C2 Fig. 2. Leaf anatomy (paradermal section) of Mukia spp. A. Mukia maderaspatana*. B. M. sumbensis. C. M. leiosperma. 1. adaxial surface. 2. abaxial surface. Scale bar = 20 µm. *Photo taken from Pratami et al. (2019). A B C Fig. 3. Leaf anatomy (transverse section) of Mukia spp. A. Mukia maderaspatana*. B. M. sumbensis. C. M. leiosperma. Scale bar = 50 µm. *Photo taken from Pratami et al. (2019). PRATAMI et al.: A new species of Mukia (Cucurbitaceae) 2022] 39 diameter, thicker tendril, retrorse indumentum on petiole, bigger indumentum on midrib, and pitted surface of its seed. Compared to M. leiosperma however, it has thinner of tendril, smaller size of seeds which have smooth surface. Climbing herbs, monoecious. Stem scabrous or stiffly­hairy, 1.8–1.9 mm diameter. Probract absent. Tendrils simple and thick (0.2 mm). Leaves: petiole 1.7–2.3 cm long, 0.7–0.9 mm diameter, hispid with short to long, downwardly curved hairs (retrorse); blade subentire or 3–5- lobed, broadly ovate, subcircular or broadly hastate in outline, 10–29 cm diam., base shallowly to deeply cordate, apex acuminate, margin variously up to 5 mm dentate, upper leaf surface hispid or scabrous-hairy, lower leaf surface hirsute hairy, bigger on midrib, indumentum color withish not shiny. Male flowers in fascicles of 2–20; pedicel 1–2 (–10) mm long. Female flowers solitary or in group up to 8; pedicel 1–2 mm long; calix and corolla not seen. Fruit 1–2 in axillary clusters, pedicel 0.2–0.5 cm, green and pale green, ripening red, darker striped or not, globose, 0.5–1.5 cm diam., with few coarse hairs; coarsely wrinkled when dry. Seeds numerous, whitish or pale brown, seeds not shining, ovate, 4.31 mm by 2.96 mm, margin narrow, faces convex, pitted or nearly smooth, groove along the edges of the seed. Paradermal leaf section showed that anatomically the anomocytic stomata are confined to the abaxial surface, scattered among the irregularly shaped epidermal cells which are somewhat elongated, bumpy or lobed. From the leaf transversal section, characteristically it has two layers of palisade tissue. Distribution. So far only known fr om Sumba. Habitat & Ecology. Highland for est. Etymology. The specific epithet r efer s to the name of the Island. Conservation status. The status of this species is unknown according to the criteria of IUCN Red List. However, it can be categorized as an endangered new species, because so far it was only found once in one location. Rarity note. Admittedly, the char acter ization of M. sumbensis is only based on a single herbarium specimen collected almost a century ago from a semi arid area in the Lesser Sunda Islands group. Nevertheless, we believe that the publication of this new species belonging to a problematical genus is fully justified especially to draw special attention to the need to do further explorations to recollect and to ascertain its very existence in relation to the present precarious situation due to the threat of extreme climate changes now taking place. ACKNOWLEDGEMENTS Thanks are due to the Ministry of Research, Technology, and Higher Education (DIKTI) for funding this research through the PMDSU scholarship programme, to the Keeper of Herbarium Bogoriense, BRIN, Cibinong for facilitating the authors to observe the specimens of Mukia, and also to Prof. Mien A. Rifai, Ph.D for his advice, suggestion and assistance in pre­ paring this paper. REFERENCES ARNOTT, G. A. W. 1840. 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