To date, 26 species of Theloderma have been described and all are distributed throughout Southeast Asia from Assam in northeastern India to Myanmar, Indochina, the Malay Peninsula, and the islands of the Greater Sundas: Sumatra and Borneo (Frost 2019). The tadpoles of only 12 species have been described and published: T. asperum (Boulenger); T. auratum Poyarkov, Kropachev, Gogoleva Orlov; T. bicolor (Bourret); T. corticale (Boulenger); T. gordoni Taylor; T. horridum (Boulenger); T. leave (Smith); T. moloch (Annandale); T. nebulosum Rowley, Le, Hoang, Dau Cao; T. palliatum Rowley, Le, Hoang, Dau Cao; T. stellatum Taylor; T. vietnamense Poyarkov, Orlov, Moiseeva, Pawangkhanant, Ruangsuwan, Vassilieva, Galoyan, Nguyen Gogoleva (Boulenger 1903; Annandale 1912; Wassersug et al. 1981; Inger et al. 1999; Leong Lim 2003; Inthara et al. 2005; Rowley et al. 2011; Gawor et al. 2012; Orlov et al. 2012; Poyarkov et al. 2015; Kropachev et al. 2018).
To date, 20 species of Kurixalus Ye, Fei, and Dubois have been described, and all of these species are distributed throughout South and Southeast Asia, from eastern India, throughout Myanmar and the mountainous regions of southern China, to Indochina, western and northern peninsular Thailand, Malaysia, Sumatra, Borneo, and the Philippines (Frost 2021). Descriptions of the tadpoles of only 6 species have been published: K. berylliniris and K. wangi Wu, Huang, Tsai, Li, Jhang, Wu (Wu et al. 2016); K. eiffingeri (Boettger) (Kuramoto Wang 1987); K. idiootocus (Kuramoto Wang) (Kuramoto Wang 1987); K. cf. verrucosus (Boulenger) (Ziegler Vences 2002), and Kurixalus yangi Yu, Hui, Rao, Yang (Humtsoe et al. 2020). A description of the tadpoles of K. baliogaster (Inger, Orlov, Darevsky) is also given in the species description (Inger et al. 1999), but described larvae are assigned tentatively to this species in the published text. Additional studies on the identification of the conspecificity of the described tadpoles with K. baliogaster have not been conducted. Based on the much larger size of the tadpole body (TL up to 40.3 mm), as well as the labial tooth row formula 6(26)/5(1) given by Inger et al. (1999), we concluded that these described tadpoles cannot be larval K. baliogaster and most likely belong to some other species of rhacophorid frogs.
Molecular phylogenetic analyses of the sister species Sphenomorphus stellatus and S. praesignis based on the mitochondrial genes 12S and 16S rRNA recover the former as paraphyletic with respect to the latter in that a specimen of S. stellatus from the type locality in Peninsular Malaysia is more closely related to S. praesignis than to Indochinese populations of S. stellatus. Furthermore, the phylogeny indicates that the Indochinese populations represent two species, thus resulting in four major lineages within this clade. These relationships are consistent with multivariate and univariate analyses of morphological and discrete color pattern data which statistically define and diagnose the four lineages and together with the molecular data, provide the foundation for robust, testable, species-level hypotheses. As such, S. stellatus is herein restricted to Peninsular Malaysia; S. annamiticus is resurrected for the circum-continental populations ranging through southeastern Thailand, southern Cambodia, and southern Vietnam; a new species-S. preylangensis sp. nov.-is described from an isolated mountain, Phnom Chi, from the Prey Lang Wildlife Sanctuary in central Cambodia; and the taxonomy of S. praesignis remains unchanged. The description of S. preylangensis sp. nov. underscores the necessity to conserve this remnant of lowland evergreen rainforest in the Prey Lang Wildlife Sanctuary.