Timonius kinabaluensis J.Chen, 2014

Chen, Junhao, Wong, Khoon Meng, Ent, Antony Van Der & Tan, Hugh T. W., 2014, Nine new species of Timonius (Rubiaceae) from Kinabalu Park, Borneo, Phytotaxa 181 (3), pp. 138-150 : 144-145

Timonius kinabaluensis J.Chen , sp. nov. ( Fig. 3A )

Similar to Timonius ophioliticus J.Chen ( Fig. 3B ), from which it differs by larger fruits (11–14 mm vs. 5–8 mm in diam.) and fewer secondary veins (3–5 vs. 5 or 6).

Type: — BORNEO. Sabah: Kinabalu Park, 4 km from Kampung Melangkap Tomis , 7 July 1996 (♀ plant), Lorence 2444 (holotype K; isotype SNP) .

Timonius cf. mutabilis in Beaman & Anderson (2004: 348), pro parte, quoad Amin SAN 115990.

Timonius sp. 2 in Beaman & Anderson (2004: 349), pro parte, quoad Lorence 387, 2444.

Tree to 9 m tall; trunk to 30 cm dbh; bark unknown. Stipules triangular, with two lateral ridges converging at the apex, imbricate. Leaves opposite; petioles 1–1.5 cm long, 1.5–2 mm in diam.; blades elliptic, 6.7–10.3 × 3.4–4.8 cm, base cuneate, apex cuspidate, margins plane, coriaceous, lower surface glabrous, upper surface plane (not bullate); secondary veins 3–5 on each side of the midrib, 12–18 mm apart from each other; tertiary veins not prominent on lower surface. Inflorescences: female plants with a solitary flower per inflorescence, peduncle length unknown, peduncular bracts whisker-like, 1.5–2 × ca. 0.5 mm; male plants unknown. Calyx lobes in female flowers 5 or 6, shape, length and pubescence unknown; in male flowers unknown. Corolla unknown. Fruits globose, 11–14 mm in diam., glabrous; peduncles 1.1–1.8 cm long, glabrous; persistent calyx lobes shallow-triangular, ca. 0.5 mm long.

Etymology: —The specific epithet refers to Mount Kinabalu.

Distribution: —Only known from Kinabalu Park.

Habitat: —Hill forest to low altitude montane forest.

Proposed conservation status: —This species is here classified as Data Deficient ( IUCN 2001) because there is insufficient information about its population size and geographic range. Known only from three specimens, this species is very poorly represented in herbaria and its status will need further assessment when more documentation will become available.

Additional specimens examined (paratypes): — BORNEO. Sabah: Kinabalu Park, Bukit Ampuan, 19 July 1986 (♀ plant), Amin SAN 115990 (L, SAN) ; Kampung Melangkap Tomis , 24 May 1995 (♀ plant), Lorence 387 (K, SAN) .

Notes: —This species is similar to T. ophioliticus , but differs by having distinctly larger fruits. Fruit diameter in the Kinabalu Timonius species is very uniform within species, typically varying only ca. 3 mm between the largest and smallest fruit observed. This narrow range in fruit diameter is not an artefact of small sample size as it is also observed in species with a large number of fruiting specimens including T. abanii (7–10 mm), T. borneensis (10–12 mm), and T. ophioliticus (5–8 mm). This taxon is recognised as a distinct species (instead of a variety of T. ophioliticus ) as it is separated from the most similar species by a morphological gap, which constitutes an indirect assessment of reproductive isolation, according to the BSC employed in this study.

Figures

FIGURE 3. A. Solitary fruit of Timonius kinabaluensis, Amin SAN 115990 (SAN). B. Solitary fruits of T. ophioliticus, Leopold SAN 81740 (L). C. Male inflorescences of T. ophioliticus, Muin SAN 31658 (SING). D. Strongly recurved leaf margins of T. tambuyukonensis, Van der Ent et al. SNP 24479 (SNP). E. Solitary female flowers of T. tambuyukonensis, Van der Ent et al. SNP 24479 (SNP). F. Stipules and female inflorescence of T. clementis, Wong & Kambira WKM 2410 (L). G. Solitary fruit of T. tambuyukonensis, Van der Ent et al. SNP 24479 (SNP). H. Solitary fruit of T. stenolobus, Clemens & Clemens 40171 (L). Scale bars: 1 cm. [Photos:A and C, J. Chen; B, F, and H, K.M. Wong; D, E, and G, A. van der Ent]