Saturday, August 17, 2013

[Botany • 2013] Winitia gen. nov. • Integrative systematics supports the establishment of Winitia, a new genus of Annonaceae (Malmeoideae, Miliuseae), allied to Stelechocarpus and Sageraea, from Thai - Malaysia peninsula

Winitia expansa Chaowasku
photo: Nonn Panitvong

The generic circumscriptions of Stelechocarpus and Sageraea (Annonaceae) are assessed using molecular phylogenetic, macromorphological, and pollen morphological evidence. For molecular phylogenetic analysis the combined seven plastid markers: rbcL exon, trnL intron, trnL-F spacer, matK exon, ndhF exon, psbA-trnH spacer, and ycf1 exon constituting c. 7 kb are used. The results corroborate the recognition of a maximally supported clade as a new genus, Winitia. It is weakly to moderately supported as sister to Stelechocarpus burahol, the type and only species of Stelechocarpus. A clade consisting of Winitia and Stelechocarpus is strongly supported as sister to Sageraea, which is monophyletic with strong support. Winitia consists of two species, one of which (W. expansa) is proposed as a new species endemic to Thailand, whereas one new combination (W. cauliflora) is made. The new genus is primarily characterized by (1) multicolumellar stigmas (≥ 5 columns per stigma) and (2) pollen grains with a very thin tectum, a more or less columellate/coarsely granular infratectum, and a very distinct basal layer. The macromorphology and pollen morphology of the three genera (Stelechocarpus, Winitia, and Sageraea) are highlighted.

Key words: Annonaceae, Miliuseae, molecular phylogenetics, morphology, nomenclature, palynology, Sageraea , Stelechocarpus , taxonomy, Winitia

งำเงาะ Winitia cauliflora (syn.: Stelechocarpus cauliflorus)

Winitia Chaowasku, gen. nov.
Type Species: Winitia expansa Chaowasku, sp. nov.
Etymology: The genus name is to honour Phraya Winit Wanandorn, who has been praised as the ‘father’ of Thai Botany.
Distribution: Two species occurring in Vietnam, southern Thailand through Peninsular Malaysia, Sumatra?, and Borneo.

Key to the species of Winitia
1a. Flowers mostly clustered on the swollen base of the trunk, pedicels 12.0–22.0 mm long, inner petals moderately spreading at maturity, adaxial side of both inner and outer petals glaucous, each stigma with 7–9(–10) columns……………… W. expansa sp. nov.
1b. Flowers usually clustered (on knobs) along the trunk, pedicels usually ≥ 30.0 mm long, inner petals connivent at maturity, no glaucous appearance observed on adaxial side of either petal whorl, each stigma with 5–7 columns…………… W. cauliflora comb. nov.

Winitia expansa Chaowasku, sp. nov.
Etymology: The epithet refers to the moderately spreading inner petals at maturity.
Distribution: peninsular Thailand

Winitia cauliflora (Scheff.) Chaowasku, comb. nov. 
 syn.: Stelechocarpus cauliflorus (Scheff.) J. Sinclair 
Distribution: Thailand, Peninsular Malaysia, Sumatra and Borneo
(Sarawak, West- and East-Kalimantan).

Tanawat Chaowasku & Raymond W.J.M. Van Der Ham. 2013. Integrative systematics supports the establishment of Winitia, a new genus of Annonaceae (Malmeoideae, Miliuseae) allied to Stelechocarpus and Sageraea. Systematics and Biodiversity. 11 (2), 195-207. 

 สกุล Winitia สกุลใหม่ล่าสุด พรรณไม้วงศ์กระดังงา (Annonaceae) |