Lithocarpus tapanuliensis
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Ordo: Fagales
Familia: Fagaceae
Genus: Lithocarpus
Name
Lithocarpus tapanuliensis Harapan, W.H.Tan, Nurainas & Strijk sp. nov. – Wikispecies link – Pensoft Profile
Type material
Holotype. Indonesia, North Sumatra Province, South Tapanuli Regency, Sipirok District, Bulu Mario Village, Pilar Forest (Fig. 2). 1°34'53.9"N, 099°11'38.2"E, elevation 894 m, 23 February 2023, Holotype: ANDA [ANDA00000051794]; Isotypes: ANDA [ANDA00000051793].
Diagnosis
Lithocarpus tapanuliensis distinguishes itself from similar species through its presence and placement of unique bullate protuberances covering the cupule and the distinct presence of a narrow ring of small denticulated plates around the rim. It differs from L. elegans (Blume) Hatus. ex Soepadmo with tiny, pointed scale-like appendages, L. confragosus (King ex Hook.f.) A.Camus with close-set warts, L. corneus (Lour.) Rehder with the diamond-like pattern and L. pulcher (King) Markgr. with tuberculate cupules. The cupule of L. tapanuliensis covers almost 3/5 of the nut (in contrast with L. pulcher and L. confragosus, whose cupule encloses almost the entire nut). The surface of the cupule is slightly tomentose and dark brown with distinct protuberances (whereas L. confragosus, L. corneus and L. pulcher lack such because of the absence of lamellae) (Table 1).
| Characters | Lithocarpus tapanuliensis Harapan, W.H. Tan, Nurainas & Strijk | L. confragosus (King ex Hook.f.) A.Camus | L. corneus (Lour.) Rehder | L. luteus Soepadmo | L. elegans (Blume) Hatus. ex Soepadmo | L. pulcher (King) Markgr. |
|---|---|---|---|---|---|---|
| 1. Cupule surface | Up to ⅘ covered with bullate protuberances; upper ⅕ with narrow ring of small denticulated plates. The surface of the cupule is slightly tomentose | Outside irregularly set with rounded to pointed short tubercles. | Outside with triangular to rhomboid bracts, the centre and margin ridged or fused with cupule and ± united into concentric rings. | Woody, tomentose, lamellate; thick, hairy, enclosing up to half of the acorn; lamellae obscure or slightly distinct, edge denticulate, set in 8–10 regular lines. | Adpressed tomentose, scale-like appendages distinct, appressed, woody imbricate, set in regular lines. | Woody, tomentose, covered in distinct sturdy tuberculate, irregularly and densely set on the upper part of cupule, spreading out towards the base. |
| 2. Nut scar | Concave. | Flat to concave, basal only. | Scar covering ½ to most of nut, convex. | Flat. | Flat to concave, basal only. | Scar covering ¾ of the nut, deeply convex. |
| 3. Size of acorns (l × w) | 1.9–2.9 cm long, 2.6–3.4 cm in diam. | 1.5–2.5 cm long, 2–4 cm in diam. | 2.5–3.4 cm long, 3.3–4.9 cm in diam. | 1–1.5 cm long, 2–2.5 cm in diam. | 1.5–2.5 cm in length, 1.5–3 cm in diam. | 2–4 cm long, 4–5 cm in diam. |
| 4. Acorn position | Sessile, solitary along the rachis and spaced. | Sessile or with stalk up to 1 cm. | Sessile, singular or in 2s, 3s or 4s. | Sessile, solitary or more common in clusters. | Sessile or with stalk up to 0.5 cm, solitary. | Sessile, solitary along the rachis. |
| 5. Nut surface | Sparsely tomentose. | Glabrous, smooth. | Tomentose around the apex. | Densely fulvous to greyish-tomentose. | Glabrous, smooth. | Sparsely tomentose, brown. |
| 6. Wall; nut covering extent of the cupule. | Free from the cupule; up to half of the nut covered. | For the greater part free from the cupule; enclosing greater part of the nut,except for opening. | Free from the cupule; enclosing ca.½ of the nut. | Free from the cupule; enclosing ca. ⅓ of the nut. | Free from the cupule; enclosing ca. ½ nut. | Mostly adnate to the cupule; enclosing greater part of the nut except for opening. |
| 7. Nut shape | Obovoid (more flat at the apex) | Depressed, ovoid-globose, top rounded and depressed umbonate at the centre, base truncate | Subglobose to turbinate, apex rounded, flat, or slightly concave | Ovoid to sub hemispherical | Ovoid or depressed ovoid to subglobose, apex rounded | Obconical- hemispherical. Top flat or convex. Base deeply convex |
| 8. Leaf shape; size (l × w) | Elliptic to oblong, (14) 16–17(20) × (4.7)6–7(8.5) cm, margin entire, apex cuspidate, base attenuate. | Elliptic to oblong, to broadly elliptic, (10–)12–18(–27) × (3.5–)5–7(–10) cm, broadest around the middle line. | Elliptic to oblong, (5–)10–15 × 2–4.5 cm. Base cuneate to subrounded and symmetric or oblique, margin dentate, shallowly undulate, or rarely entire, apex acuminate to acute. | Elliptic to obovate, (7–)9–12 (–15) × (2.5 –) 3.5–5 (–6) cm, broadest at or slightly below the middle, base acute to cuneate, top acute to 1 cm acuminate. | Narrowly to broadly obovate or elliptic, (9–)12–17(–21) × 3–6(–8) cm base acute or cuneate, margin revolute, apex bluntly acute or acuminate. | Broadly elliptic to oblong, (10–) 15–20(–30) × (4–) 6–8(–12.5) cm, base acute to cuneate, margin revolute, apex acute to acuminate. |
Description
A large tree without buttresses, up to 35 m tall. Bark rough, lightly fissured, greyish-green with whitish lenticel. Inner bark is dark red forming longitudinal slits. Twigs diameter 0.2–0.4 cm, smooth, striate, bud imbricate 0.5 mm. Branches dark brown. Leaves simple, underneath tomentose, dark green above and fawn green below when fresh; above, dull greyish-brown, lightly brown when dry. Blade elliptic-oblong, 16.5–20 (L) × 6–8.5 (W) cm; margin entire; apex cuspidate tip; bases attenuate. Petiole: striate, glabrous, 1.3–1.5 cm in length. Venation mid-rib wide, raised on both sides; pinnately veined, secondary venation eucamptodromous. Pairs of secondary nerves 10–11 pairs, raised on the underside. Tertiary veins sub-scalariform. Male and female inflorescences not seen. Peduncles up to 2–4 cm long and between 0.3 and 0.5 cm in diameter. Infructescence rachis diameter 0.4–0.5 cm. Acorn solitary along the rachis and spaced both in immature and mature stages. Cupule solitary and sessile, greenish-brown when fresh, mature cupules cup-shaped covering half of the nut, diameter 2.8–3.4 cm, cupule thickness 2.4–2.8 cm. thick-walled woody, cupule surface irregular, with a narrow ring of small denticulated plates around the rim, rest of cupule covered in distinct bullate protuberance gradually fusing into large tumour-like masses towards the base. Protuberances, specifically the rim, have resin burn marks with blackish shiny colour when dried. Immature cupules thin, cup-shaped covering 80% of the nut, covered in small protuberances ranging from relatively flat lines to bullate. Nut obovoid, length 1.9–2.3 cm, diameter 2.2–2.6 cm, sparsely tomentose around the basal scar, fawn-green when ripe, brownish-grey when dried, basal scar depressed, nut scar diameter 1.6–1.7 cm, thickness 0.3–0.4 cm. Resin leaking on the nuts. Apex flattened obtuse.
Phenology
Fruiting was observed in February 2023 with fresh fruits recovered from the tree and from the ground.
Distribution, habitat and ecology
During our fieldwork in Pilar Forest, a primary forest near the Bulu Mario District, we recorded two individuals of Lithocarpus tapanuliensis. The lower-montane forest is characterised by the abundance of meranti gunung (Shorea platyclados Slooten ex Endert). Additional Fagaceae species were recorded, namely Lithocarpus javensis Blume, Quercus oidocarpa Korth. and Castanopsis tungurrut (Blume) A.DC. Interactions with Tapanuli orangutans were observed with a nest and remnants of consumed fruits were recorded near the tree (Fig. 3). Sipirok Regency precipitation typically varies during different sections of the year. Maximum monthly precipitation is 296.5 mm and the minimum monthly precipitation is 67 mm, with an average temperature around 28 °C (Badan Pusat Statistik 2023).
Vernacular name
Hoteng (Tapanuli language).
Etymology
The epithet is derived from its type locality, Tapanuli, South Tapanuli District, Sipirok Regency, North Sumatra Province, Indonesia.
Conservation status
Using the guidelines established by the IUCN Red List (IUCN Standards and Petitions Committee 2022[4]), we provide an initial conservation assessment of the species as Critically Endangered (B1ab(iii) + B2ab(iii), D), based on only two recorded individuals within Pilar Forest, its limited range and extensive habitat alteration and forest clearance in the immediate vicinity of the forest and throughout Sumatra. Pilar Forest does not have any legal protection or governance, but is immediately adjacent to Dolok Sibual-buali Nature Reserve. Both are part of the wider Batang Toru ecosystem landscape (150,000 ha; Fredriksson and Usher (2017)[5]). Under this programme, the area is targeted for protection, ecosystem restoration and sustainable tourism development through a combination of NGOs and the State. More information and images are available on the species webpage (www.asianfagaceae.com/lithocarpus_tapanuliensis/) and GBIF.
Original Description
- Harapan, T; Tan, W; Febriamansyah, T; Nurainas, ; Syamsuardi, ; Strijk, J; 2023: Lithocarpus tapanuliensis (Fagaceae), a new stone oak from northern Sumatra and its role as an important resource for critically endangered orangutans PhytoKeys, 234: 167-179. doi
Images
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![Figure 2. Distribution map of Lithocarpus tapanuliensis sp. nov. in South Tapanuli, North Sumatra. The inset map shows the location of the sampling region on Sumatra Island, Indonesia. Elevation was obtained from SRTM (2023)[6]. Map by T.S. Harapan.](/wiki/File:Phytokeys-234-167_article-106015_-g002.jpg)
Other References
- ↑ Cockburn P (1972) Fagaceae. In: Whitmore T (Ed.) Tree Flora Malaya (Vol.1). Longman Malaysia, Kuala Lumpur, 196–232.
- ↑ Soepadmo E (2000) Fagaceae. In: Soepadmo E Saw L (Eds) Tree Flora of Sabah and Sarawak (Vol.3). Sabah Forestry Department, Forest Research Institute Malaysia (FRIM), Sarawak Forestry Department, 119–180. https://doi.org/10.26525/TFSS3001
- ↑ Phengklai C (2008) Fagaceae (Vol.9 (3)). In: Santisuk T, Larsen K, Nielsen I, Chayamarit K, Phengkhlai C, Pedersen H, Parnell J, Middleton D, Newman M, Simpson DA, van Welzen PC, Hul S, Kato M (Eds) Flora of Thailand. The Forest Herbarium, National Parks, Wildlife and Conservation Department, Bangkok.
- ↑ IUCN Standards and Petitions Committee (2022) Guidelines for using the IUCN red list categories and criteria. Version 15.1. Prepared by the Standards and Petitions Committee. https://www.iucnredlist.org/documents/RedListGuidelines.pdf [Accessed August 24, 2023]
- ↑ Fredriksson G, Usher G (2017) Towards Sustainable Management of the Batang Toru Ecosystem (translated from Edisi III dari “Menuju Pengelolaan Lestari Ekosistem Batang Toru). Yayasan Ekosistem Lestari, Medan.
- ↑ SRTM (2023) SRTM 90m Digital Elevation Database. http://www.srtm.csi.cgiar.org [Accessed May 18, 2023]
