Four new orchid species from the Lengguru fold belt, West Papua, Indonesia

Abstract Bulbophyllum leucoglossum, Dendrobium centrosepalum, Dendrobium taeniocaule, and Taeniophyllum pyriforme are here described as new species, based on herbarium specimens collected from the Lengguru fold-and-thrust belt in the West Papua Bird’s neck, Indonesian New Guinea. All four novelties were found growing in submontane forest (elevation > 1000 m a.s.l.) on limestone karst. Information concerning the distribution and habitat for these taxa is provided along with diagnostic features, line drawings, high resolution photographs, and a map of collecting localities. More field studies are required to find additional populations of these new species, in order to better characterize their habitat, ecology and conservation status.


Introduction
Indonesia has been classifi ed as a megadiverse country (Mittermeier et al. 1997), and is estimated to house approximately 10% (30,000 species) of the botanical diversity of the world (World Resources Institute et al. 2005). Th e country is composed of over thirteen thousand islands lining the equator. Th e largest island, New Guinea, is also known to harbour one of the richest orchid fl oras in the world, only surpassed by Colombia, Ecuador, and Peru (Schuiteman and de Vogel 2007). Ormerod (2014) recorded c. 2870 species of orchids from New Guinea, 11% of the world's orchid fl ora, of which about 95 percent are endemic to the island (Schuiteman et al. 2001(Schuiteman et al. -2010. Considering that large parts of New Guinea still have low collecting densities, it is likely, as also suggested by Ormerod, that many species still await discovery here. Th e island has a complex geological history, related to the tectonics of the Indo-Australian and Pacifi c plates. Th e Lengguru fold-and-thrust belt (Bailly et al. 2009) was formed by the collision of the Australian and Pacifi c plates, and is characterized by a series of parallel and oblique folds separated by deep valleys, which link the high mountains of the Central Range of western Papua to the moderately high mountains of the Bird's neck. According to Vollering et al. (2016), the orchid species diversity in this part of New Guinea, which at present has a very low collecting density, is predicted to be relatively low, compared to the high diversity of the Eastern Highlands and Chimbu provinces of Papua New Guinea. Th is prediction was based on species distribution modelling using occurrence records of 532 species and spatial environmental data. It will be interesting to see if the prediction holds up once the area is better known botanically.
In October-November 2014, the fi rst and the last authors took part in the Lengguru 2014 scientifi c expedition (www.lengguru.org). One of the main objectives of this multidisciplinary research programme was to make a rapid but wide-ranging assessment of the botanical diversity in a major Papuan karst region. Th e ultimate goals are to generate species plant checklists for this poorly sampled area, and to incorporate these data into a regional database to further analyse plant distribution patterns at diff erent scales. During the Lengguru expedition, we sampled 26 diff erent sites in the limestone karst landscape (primarily swamp forest, mature lowland forest, alluvial forest, and submontane forest) from the sea shore to the top of the anticlines at around 1500 m elevation, in three main localities: Lobo village, Triton Bay; Urisa village, Arguni Bay; and Nusa Ulan, Kumawa Forest Reserve (Fig. 1). We gathered 72 fertile/fl owering orchid specimens and associated material (pictures, silica-gel samples). We also collected living orchid specimens, which are now being cultivated in the Kebun Raya, Bogor (West Java) and in the Wamena Biological Gardens (Papua). Detailed examinations and comparisons with nomenclatural types of related species present in New Guinea, allowed us to identify four new species in the genera Bulbophyllum Th ouars, Dendrobium Sw., and Taeniophyllum Blume. Th ese novelties are described in the present paper, complemented with line drawings, photos, and information on habitats and distribution. As far as we now know, all four new species are endemic to the submontane forests of the Lengguru fold belt, at elevations above 1000 m.

Materials and methods
Most orchid collections from the Lengguru expedition were preserved in Copenhagen mix (ethanol 70% and 5% glycerol). Specimens are deposited mainly in BO, with some duplicates in MAN, K, P and L (herbarium acronyms according to Th iers, continuously updated). Measurement and drawing of vegetative and reproductive parts were made on liquid preserved specimens, using a Wild Heerbrugg Switzerland Type 308700 stereo microscope. Additional data such as colour, habitat or ecology are mainly derived from fi eld notes and high resolution pictures taken during the expedition. Description. Epiphytic herb. Rhizome short, creeping; roots wiry, branching, 0.5 mm diam. Pseudobulbs closely spaced, light green, narrowly ovoid, 2.0-2.4 × 0.7-0.8 cm, with c. 10 longitudinal grooves, 1-leaved. Leaf deeper green, linear-elliptic, gradually narrowed towards the base, 8.8-10.3 × 1.3-1.4 cm, thin-coriaceous, apex acute. Infl orescences arising from the base of the pseudobulb, becoming fascicled, erect, 1-fl owered. Peduncle wiry, erect-patent, 1-fl owered, 7-9 cm long, glabrous, with two tubular, 4 mm long peduncle-scales. Floral bract tubular, strongly oblique, 4.5 mm long, apex acuminate. Pedicel-with-ovary terete, very slender, weakly 6-ribbed, almost straight or curved, c. 2.5 cm long, glabrous. Flowers opening widely, the sepals patent to refl exed; sepals and petals maroon; lip white, at base wine-red, basal part of the keels sulphur-yellow; column cream-colour tinged maroon, swollen basal part and foot light green; anther pale greenish. Dorsal sepal linear-oblong, 14.3 × 2.8 mm, 3-veined, apex acute. Lateral sepals free, obliquely linear-oblong, 13.4 × 3.3 mm, 3-veined, apex acute. Petals linear-oblong, slightly widened towards the base, glabrous, 2.6 × 0.8 mm, apex obtuse. Lip clawed, slightly mobile, attached to the column-foot by a 0.3 mm long, 0.4 mm wide ligament; claw in the basal half almost quadrangular, tapering towards the blade, 2.4 × 1.5 mm, glabrous, with erect, hemi-elliptic, lobe-like margins in the basal half; blade narrowly oblong, slightly tapering towards the apex, cucullate, strongly convex above, 9.7 × 2.3 mm, margins defl exed, fi nely lacerate-fi mbriate; blade adaxially with one median keel and two lateral keels on each side, the keels fi nely lacerate-fi mbriate; on the concave abaxial side with two lacerate-fi mbriate lamellae; apex obtuse. Column 2.3 mm long, curved, strongly swollen at the base, with a short but distinct, thick, 1 mm long column-foot; apical column-wings each with two short obtuse teeth, the wings 0.4 mm wide; stigma in lateral view with protruding lower margin; anther helmet-shaped, 0.6 mm long, very slightly papillose; pollinia not seen.

Taxonomic novelties
Distribution and habitat. Bulbophyllum leucoglossum is only known from the Lengguru fold belt in West Papua. It is currently recorded from a single location in the Kumawa Forest Reserve, near the village of Nusa Ulan (Fig. 1). Th e only population seen so far was found in submontane forest at 1005 m elevation, the plants growing epiphytically about 1.5 m from the ground on a slender, moss-grown, overhanging tree trunk in medium-sloping terrain. More than ten individuals were observed in the collecting locality, but only one was fl owering at the time of our fi eldwork (November).
Etymology. From the Greek leuco-, white, and glossum, tongue, referring to the largely pure white lip.
Notes. A distinctive species because of the fi ve laciniate-fi mbriate keels on the lip, which give it a hairy appearance. Th e only other known species in the large section Codonosiphon with a distinctly hairy-looking lip is B. pyroglossum Schuit. & de Vogel from Papua New Guinea, which is similar in plant habit and in the size of the fl ower. See the diagnosis for the main diff erences between the two species.
Dendrobium (section Calyptrochilus Schltr.) centrosepalum Schuit., Juswara & Droissart, sp. nov. urn:lsid:ipni.org:names:77153387-1 Figs 2B, 3E-H Diagnosis. Th e short and dense infl orescences with small, purple fl owers and greentipped, long-apiculate sepals resemble those of Dendrobium purpureum Roxb., a lowland species from Maluku and Sulawesi. However, the plant habit of the latter is completely diff erent, as D. purpureum has robust, many-leaved, cane-like, tufted stems up to more than 50 cm long. Vegetatively, D. centrosepalum is more similar to D. aurantiroseum P.Royen ex T.M.Reeve from New Guinea, which also has unifoliate pseudobulbs on a creeping rhizome. However, the latter is a species from high elevations (2100-3350 m) with pink fl owers that are about twice as large, while the sepals are not apiculate; in addition, the cross-ridge on the lip is situated below the middle in D. aurantiroseum and above the middle in D. centrosepalum.
Distribution and habitat. Dendrobium centrosepalum is only known from the Lengguru fold belt in West Papua. It is currently known from a single locality in the Triton Bay area, near the village of Lobo (Fig. 1). Th e only population seen so far was found in submontane forest at 1114 m elevation, the plants growing epiphytically on a thick, vertical, moss-and-lichen-covered trunk of a tree.
Etymology. From the Greek centron, a sharp point, referring to the apiculate sepals. Notes. Th e small, bright purple fl owers in short and dense infl orescences superficially resemble those of such species as D. dichaeoides Schltr. and D. limpidum Schuit. & de Vogel, but these are quite diff erent vegetatively, having elongate, leafy stems; in addition, in these two species the sepals are not sharply apiculate. See the diagnosis for additional comparisons.  the relatively much broader dorsal sepal, in the lip being wider than long (versus longer than wide), and especially in the much wider (8.5 versus 3.2 mm), bilobulate (versus entire) mid-lobe of the lip.
Distribution and habitat. Dendrobium taeniocaule is only known from the Lengguru fold belt in West Papua. It is currently recorded from a single locality in the Triton Bay area, near the village of Lobo (Fig. 1). Th e only population seen so far was found in submontane forest at 1114 m elevation, the plants growing epiphytically on a vertical, lichen-covered trunk of a tree.
Etymology. From the Greek taenia, a band or strap, and caulon, stem; referring to the fl attened, band-shaped pseudobulbs.
Notes. Th is species has only one obvious close relative, which is the widespread D. viridifl orum. Uniquely in section Brevisaccata, these two species share fl attened stems and abbreviated infl orescences that produce up to 3, 1-fl owered branches in succession over a longer period. Th e other species in the section have terete stems and fl owers produced simultaneously on elongate racemes. In addition to clear morphological diff erences, as indicated in the diagnosis, the two fi rst-mentioned species also have diff erent ecologies. While D. viridifl orum is exclusively found in mangroves and coastal forest below 200 m, D. taeniocaule occurs in submontane forest above 1000 m. Description. Leafl ess epiphytic herb. Stem very short; roots spreading, green, fl attened, not branching, up to at least 35 cm long, 1.5-3 mm wide; some of the roots closely appressed to the bark of the phorophyte, others free hanging. Infl orescences c. 3 producing fl owers at the same time, suberect, 5-6 cm long; peduncle fi liform, 0.5 mm diam., rather sparsely muricate with c. 0.3 mm long projections; near the middle with a very small peduncle-scale; rachis distichous, glabrous, up to c. 16-fl owered, with the fl owers opening in succession, one or two at a time, gradually elongating, up to 11-14 mm long. Floral bracts cupular, in lateral view triangular, subacute, 1.2 mm long; successive bracts on the same side of the rachis 1.8 mm apart. Flowers apparently non-resupinate (always?), c. 5 mm high including the spur, glabrous, pale brownish yellow. Dorsal sepal ovate, 3.3 × 1.5 mm, obtuse, 3-veined. Lateral sepals somewhat obliquely ovate, 2.6 × 1.3 mm, obtuse; 3-veined; abaxially at the apex with a short lamella along the midvein. Petals obliquely ovate, 3.2 × 1.5 mm, obtuse, 3-veined. Lip spurred, 3-lobed, ecallose, margins erect to incurved, when fl attened 2.7 × 3.2 mm; lateral lobes semi-oblong, rounded, 2.0 mm long from base of lip to base of mid-lobe, at the base with an erect, narrowly triangularuncinate lobule; mid-lobe reniform, 0.7 × 1.2 mm, emarginate. Column short, cylindrical, 1.1 long, 1.0 mm wide, with a short, bidentate rostellum; stigma shallowly concave; anther cucullate, 0.9 cm long, 0.6 cm wide, apex rostrate, recurved; pollinia not seen.

Taeniophyllum (section
Distribution and habitat. Taeniophyllum pyriforme is only known from Papua. It is recorded from a single locality near the village of Lobo in the Triton Bay (Fig. 1). Th e only population seen so far was found in submontane forest at 1114 m elevation, the plants growing epiphytically on a sparsely moss-covered tree trunk at 1.5 m above the ground.
Etymology. From the Latin pyriforme, pear-shaped, referring to the shape of the spur. Notes. Th is inconspicuous but distinctive species would seem to fi t best in section Loboglossum, on account of the clearly lobed lip, elongate infl orescence, distichous rachis, and glabrous ovary. However, a muricate infl orescence has not been reported for this section before (although the otherwise very diff erent Taeniophyllum toranum J.J.Sm. is described as having a furfuraceous-punctate peduncle and rachis, while the no less distinct T. pulvinatum is said to have a minutely glandulose peduncle). Th e basal, hook-like lobules on the lip are also unique.
It is likely that a large number of species of Taeniophyllum still await discovery in New Guinea. We believe this to be the case because most of the species are easily overlooked; the fl owers often last only a day or less; and many of the known species are only recorded from the type. New Guinea is clearly the centre of diversity for this genus, with 130 species currently recorded.

Conclusions
Th e four new species described here demonstrate that, most likely, many new species still await discovery in poorly explored parts of New Guinea. Among our collections from the Lengguru area, 1 out of 8 species of Bulbophyllum, 2 of 22 Dendrobium species, and 1 of 2 Taeniophyllum species proved to be new to science, and 3 of these novelties were collected on the same day near Lobo village. Th is only represents species found in fl ower during our expedition, which is certainly a minority of the total orchid fl ora of the area.
Th e new species of Bulbophyllum and Dendrobium described here, while distinctive, do not present striking new features for these genera; they are easily classifi ed among the known species. Th e new Taeniophyllum, on the other hand, appears to be without any obvious close relatives. Th is genus in particular warrants much more attention from scientifi c collectors and taxonomists; the diversity and phylogenetics of this genus are still poorly understood.