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| Goniothalamus obovatus Chaowasku & Damth., in Damthongdee, Narintarangkul Na Ayutthaya, Chanthamrong, Ruangritthidech, Wiya et Chaowasku, 2025. |
Abstract
Goniothalamus obovatus Chaowasku & Damth., a new species of Annonaceae from southern Thailand is described and illustrated. It is morphologically most similar to G. banii endemic to Vietnam, but can be distinguished from it by possessing terete (vs ± angular) branches, a subcordate to cordate (vs rounded) leaf base, shorter inner petals, an inner petal apex that is ± acute (vs long-acuminate), a lower ratio of inner petal to outer petal length, fewer stamens per flower, a staminal connective apex that is ± apiculate (vs rounded), fewer carpels per flower and densely hairy (vs glabrous) ovaries. The conservation status of the new species is provisionally assessed as Data Deficient.
Keyword: Annoninae, Goniothalamus, Goniothalamus banii, new species, Satun, taxonomy, Thailand
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| Flowers and floral organs of Goniothalamus obovatus sp. nov. A. Flowers. B. Flower with one outer petal removed. C. Adaxial side of outer petal. D. Adaxial side of inner petal. E. Flower with petals removed. F. Flower with petals, stamens and carpels removed. G. Abaxial side of stamen. H. Carpel. All from the holotype (B–H from material in spirit). |
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| Holotype of Goniothalamus obovatus sp. nov. at CMUB. |
Goniothalamus obovatus Chaowasku & Damth., sp. nov.
Diagnosis: The new species morphologically most similar to G. banii B.H.Quang, R.K.Choudhary & V.T.Chinh endemic to Vietnam (Quang et al., 2016) mainly in leaf, sepal and outer petal shape, as well as number of ovules per ovary, but distinguishable from it by having terete (vs ± angular) branches, a subcordate to cordate (vs rounded) leaf base, shorter inner petals, an inner petal apex that is ± acute (vs long-acuminate), a lower ratio of inner petal to outer petal length, fewer stamens per flower, a staminal connective apex that is ± apiculate (vs rounded), fewer carpels per flower and densely hairy (vs glabrous) ovaries (Table 1).
Etymology: The specific epithet refers to the obovate
leaves of this species.
Anissara Damthongdee, Pimjan Narintarangkul Na Ayutthaya, Kithisak Chanthamrong, Setthikij Ruangritthidech, Chattida Wiya and Tanawat Chaowasku. 2025. Goniothalamus obovatus (Annonaceae), A New Species from southern Thailand. Taiwania. 70(4); 631-634. DOI: 10.6165/tai.2025.70.631 [04 September 2025]
