The agamaensis group (Fig. 6) is composed of at least 10 nominal, generally allopatric species (Figs 3, 7) formerly known in part as the ‘swamp clade’ (Grismer et al. 2012b:fig. 4). Species in this group are distributed across the Thai-Malay Peninsula south of the Isthmus of Kra to Sumatra, and the Riau Archipelago of Indonesia (Grismer and Davis 2018:fig. 5). Phylogenetic relationships in the group support multiple historical interchanges of lineages between the Thai-Malay Peninsula and Sumatra, as well as adjacent island chains (Grismer and Davis 2018; O’Connell et al. 2019). The group has four potentially undescribed putative species from Sumatra—cf. agamensis MH248907, sp. Sumatra GU550728, sp. Sumatra MH248914, and sp. Sumatra KR921711—that are currently being examined in an integrative taxonomic framework. Ongoing molecular analyses will likely reveal additional species belonging to this group (O’Connell et al. in prep.).

Another species, Cyrtodactylus camortensis from the central islands of Camorta, Katchall, and Nancowry in the Nicobar Archipelago, may belong to this group. Samples were absent from the ND2 phylogeny but it is deeply nested within this group in the nuclear phylogeny (Fig. 4). However, the agamensis group in the nuclear phylogeny is paraphyletic so additional ND2 data are necessary to confirm its species group placement. Prior to its revision by Chandramouli (2020), this specimen was recognized as C. adleri in Agarwal et al. (2014).

Figure 6. 

Examples of the Cyrtodactylus agamensis group. A. C. psarops from Sumatra, Indonesia. Photo by Eric N. Smith. B. C. metropolis from Selangor state, Peninsular Malaysia. Photo by L. Lee Grismer. С. C. tiomanensis from Tioman Island, Pahang State, Peninsular Malaysia. Photo by L. Lee Grismer. D. C. rosichonarieforum from Natuna Besar Island, Indonesia. Photo by L. Lee Grismer.

Figure 7. 

Distribution of the darmandvillei, malayanus, and agamensis species groups of Cyrtodactylus as delimited here.

Until recently, the angularis group (Fig. 8) contained only one species C. angularis (Smith 1921). It now encompasses a large radiation (Fig. 3) of mostly allopatric (Fig. 9), karst-adapted species from central Vietnam, central and northern Laos, eastern and cenrtal Thailand, and possibly southernmost China (Nazarov et al. 2014, 2018; Luu et al. 2014, 2016; Sitthivong et al. 2019:figs. 6, 7). All bear a characteristic banding pattern of well-defined hour glass-shaped dorsal bands. The only exception is C. nigriocularis, which occurs much farther south in Ba Den Mountain in Tay Ninh Province, southern Vietnam, and inhabits granite boulder caves (Fig. 8B). The angularis group includes at least 21 nominal species, of which 17 are analyzed herein along with three other potentially new species (Fig. 3). Over 80% of the group’s diversity was described within the last 15 years. In previous studies, this species group was referred to as the C. phongnhakebangensis group (as defined by Luu et al. 2016; see also Nazarov et al. 2018). Species not included in this analysis—C. khammouanensis (Nazarov et al. 2014), C. muangfuangensis (Sitthivong et al. 2019), C. rufford (Luu et al. 2016), and C. thathomensis (Nazarov et al. 2018) were demonstrated to belong to the C. angularis group in earlier integrative analyses using morphology and the mitochondrial gene CO1. The recently reported “C. zhaoi” from Yunnan Province of China (Zhu and Rao 2020) cannot be confidently assigned to any species group, but from the overall external morphology it resembles the species of the angularis group. However, it does not meet the ICZN requirements (Article 16.4.1; ICZN 2000) for being a validly described species in that there is no information on name-bearing type material given in the original publication.

Figure 8. 

Examples of the Cyrtodactylus angularis group. A. C. sommerladi from Khammouan Province, Laos. Photo by Vinh Quang Luu. B. C. nigriocularis from Tay Ninh Province, Vietnam. Photo by Nikolay A. Poyarkov. С. C. soudthichaki from Khammouan Province, Laos. Photo by Vinh Quang Luu. D. C. phongnhakebangensis (juvenile) from Quang Binh Province, Vietnam. Photo by Thomas Ziegler.

Figure 9. 

Distribution of the angularis, brevipalmatus, chauquangensis, condorensis, irregularis, and philippinicus species groups of Cyrtodactylus as delimited here and C. badenensis.

Phylogenetic relationships at the deep nodes within this group were well-resolved with the ND2 data unlike those recovered by CO1 (e.g., Sitthivong et al. 2019) and suggest C. nigriocularis is the sister species to all other members of this group (Fig. 3). The remaining angularis group species are clustered in three major subclades, one of which joins three species from eastern Thailand and northern Laos (C. angularis, C. chanhomeae, and C. pageli), the second joins species from the central Annamite karst area of eastern Laos and central Vietnam (C. roesleri, C. sommerladi, C. bansocensis, C. lomyenensis, C. jaegeri and C. soudthichaki), and the third consists of a widespread radiation of karst-adapted species from eastern Thailand (C. jarujini), Laos (C. multiporus, C. teyniei, C. hinnamnoensis, C. darevskii, and C. calamei), and Vietnam (C. phongnhakebangensis). Our analysis additionally revealed three potentially undescribed species from the latter clade (HLM 0349, HLM 0324, and HLM 0353); all from Khammouan Province, Laos. Their taxonomic assessments are currently being assessed (Poyarkov et al. in prep). Given that the karstic habitats of Laos and central Vietnam belong to one of the world’s largest limestone areas—many parts of which still remain unexplored—additional field surveys coupled with integrative taxonomic studies will likely reveal new species of narrow-range endemics belonging to this group in need of protection.

The brevipalmatus group is composed of three nominal arboreal species (Figs 3, 10) that range from central Laos through Thailand to southern Peninsular Malaysia (Smith 1930; Ulber 1993; Grismer 2008; Nazarov et al. 2018:fig. 7) (Fig. 9). Potentially new species (Fig. 3) have been reported from Langkawi Island (С. cf. brevipalmatus USMHC 2555) in northern Peninsular Malaysia (Grismer et al. 2015) and central Laos (С. cf. interdigitalis JQ889181). A new species from southwestern Thailand (sp. Suan Phueng HLM 0372) that is sister to C. interdigitalis is currently being described (Grismer et al. in prep).

Figure 10. 

Examples of the Cyrtodactylus brevipalmatus group. A. C. elok from Negeri Sembilan State, Peninsular Malaysia. Photo by L. Lee Grismer. B. C. interdigitalis from Petchabun Province, Thailand. Photo by Montri Sumonta. С. С. cf. brevipalmatus from Langkawi Island, Kedah State, Peninsular Malaysia. Photo by Evan S. H. Quah. D. C. interdigitalis from Petchabun Province, Thailand. Photo by Nikolay A. Poyarkov.

The chauquangensis group is composed of species endemic to limestone massifs in northern Indochina, ranging from northern Thailand and Laos, to northeastern Vietnam, and to Yunnan Province in southern China (Fig. 9). This group was previously referred to as the C. wayakonei species group (Nguyen et al. 2015b; Luu et al. 2016; Brennan et al. 2017; Pham et al. 2019; Schneider et al. 2020), and composed of generally karst-adapted species with characteristic yellowish spots and reticulations on dorsal surface of the head and body (Fig. 11). Until recently, no Cyrtodactylus species were known from the highland areas of the northwestern Vietnam and northern Laos (Ngo and Chan 2011) and the first species of this group, C. chauquangensis, was discovered only 13 years ago (Quang et al. 2007). In the phylogeny (Fig. 3), the group is composed of 17 nominal species, plus a putative new species (HLM 0357) from northern Thailand, the description of which is in progress (Grismer et al. in prep).

Figure 11. 

Examples of the Cyrtodactylus chauquangensis group. A. C. soni from Ninh Binh Province, Vietnam. Photo by Minh Duc Le. B. C. dumnuii from Chiang Mai Province, Thailand. Photo by Montri Sumontha. С. C. puhuensis from Thanh Hoa Province, Vietnam. Photo by Sang Ngoc Nguyen. D. C. cucphuongensis from Ninh Binh Province, Vietnam. Photo by Vinh Quang Luu.

Phylogenetic relationships within the chauquangensis group have remained stable in many analyses, but the topology recovered by this study differs from those reported by Brennan et al. (2017), Pham et al. (2019), and Schneider et al. (2020). The previous studies, based solely on CO1 and limited species coverage (Pham et al. 2019 and Schneider et al. 2020), recovered unresolved relationships at the deep nodes. In this study, the two species from northwestern Vietnam C. bichnganae and C. taybacensis form a clade that composes the sister lineage to the remainder of the group (Fig. 3). The remaining species are clustered in several clades, with the clade joining the species from northwestern Thailand (C. erythrops, C. doisuthep, and Cyrtodactylus sp. HLM 0357) forming a sister lineage to clades joining species from northern Thailand (C. auribalteatus, C. dumnuii), northern Laos (C. spelaeus, C. vilaphongi, C. wayakonei) and northwestern Vietnam (C. sonlaensis, C. huongsonensis, C. soni, C. chauquangensis, C. cucphuongensis, C. puhuensis, C. bobrovi, and C. otai). At least four species, C. auribalteatus, C. doisuthep, C. dumnuii, and C. erythrops are placed in the phylogeny here for the first time. Even though not included in our analyses, C. martini from southeastern Yunnan and C. houaphanensis and C. ngoiensis from northeastern Laos, also belong to the chauquangensis group based on their phylogenetic relationships and morphological similarity to C. wayakonei from northern Laos (Nazarov et al. 2014; Pham et al. 2019; Schneider et al. 2020). Two formally undescribed Cyrtodactylus species were recently reported from other parts of Yunnan Province, “C. caii” and “C. xiaoheijiangensis” (Zhu and Rao 2020). However, their descriptions not meet the ICZN requirements (Article 16.4.1; ICZN 2000) for being a validly described species in that there is no information on name-bearing type material given in the original publication. Further herpetological surveys in karstic areas of southern China and northern Indochina will likely result in discovery of numerous new populations of narrow-range endemics of the C. chauquangensis species group in need of protection.

The condorensis group (Fig. 12) is composed of four nominal species (Fig. 3) that range from the Mekong Delta of Vietnam eastward to the Con Dao Islands and southward across several islands in the Gulf of Thailand to Tenggol and Kra islands of Peninsular Malaysia and Thailand, respectively (Chan and Norhayati 2010; Grismer and Grismer 2017; Nurngsomsri et al. 2019:fig. 7) (Fig. 9). Grismer and Grismer (2017) demonstrated this group is composed of two ecomorphologically specialized granite cave dwellers (C. eisenmanae, and C. grismeri) and two general scansorial granite forest species (C. condorensis and C. leegrismeri). The monophyly of the group is strongly supported (100/1.00) with the exclusion of its putative sister species C. badenensis (Fig. 3).

Figure 12. 

Examples of the Cyrtodactylus condorensis group. A. C. condorensis from Hong Chong Island, Kien Giang Province, Vietnam. Photo by L. Lee Grismer. B. C. eisenmanae from Hon Son Island, Kien Giang Province, Vietnam. Photo by Ngo Van Tri. С. C. leegrismeri from Hon Chuoi Island, Ca Mau Province, Vietnam. Photo by L. Lee Grismer. D. C. grismeri from An Giang Province, Vietnam. Photo by L. Lee Grismer.

The darmandvillei group is composed of seven nominal species and at least six potentially new species (Fig. 3). Species in this group vary greatly in size (45–85mm SVL) and ecology (terrestrial to arboreal), but tend to have quite prominent and densely arranged enlarged tubercles across the body (Fig. 13) in addition to usually having contiguous femoral and precloacal pores. Based on distribution and morphology, it is likely that at least four additional species for which sequence data are unavailable also belong to this group: C. celatus, C. tambora, C. tanahjampea, and C. wetarensis. This group has one of the widest geographic distributions of any of the other species groups (Fig. 7). Its diversity is centered in Wallacea (Bali in the west, Sulawesi to the north, and the Kai Islands to the east), but geographically outlying species occur on islands off the east and west coasts of Peninsular Malaysia (C. seribuatensis and C. batucolus, respectively), Java (C. petani), Christmas Island (C. sadleiri), and Western Australia (C. kimberleyensis). This strikingly insular distribution indicates multiple overwater dispersals onto small islands, even though the lineage is conspicuously absent or unrecorded from some of the nearby mainland areas (especially Peninsular Malaysia and New Guinea). Based on this observation, it has been hypothesized that this is an insular/disturbance specialist lineage that is good at dispersing, but struggles to persist in ‘mainland’ tropical rainforest environments (Oliver et al. 2018).

Figure 13. 

Examples of the Cyrtodactylus darmandvillei group. A. C. seribuatensis from Seribuat Island, Johor State, Peninsular Malaysia. Photo by L. Lee Grismer. B. C. batucolus from Besar Island, Johor State, Peninsular Malaysia. Photo by L. Lee Grismer. С. C. darmandvillei from Nusa Penida Island, Indonesia. Photo by Ruchira Somaweera. D. C. petani from Java, Indonesia. Photo by Awal Riyanto.

The fasciolatus group is composed of a single nominal species and at least one undescribed species (Figs 3, 14). This group is restricted to the Western Himalayas in India, bordering Nepal to the east (Fig. 15). It is possible this clade extends farther east into Nepal, though all sampled Cyrtodactylus to the west of the range of the fasciolatus group are members of the lawderanus group. Wood et al. (2012) and Agarwal et al. (2014) recovered the fasciolatus group as nested within a peguensis + khasiensis clade.

Figure 14. 

Examples of the Cyrtodactylus fasciolatus group. A. C. fasciolatus from Himachal Pradesh state, India. B. C. fasciolatus from Himachal Pradesh state, India. С. C. fasciolatus from Himachal Pradesh state, India. D. С. cf. fasciolatus from Uttarakhand state, India. Photos by Ishan Agarwal.

Figure 15. 

Distribution of the fasciolatus, khasiensis, lawderanus, and triedrus species groups of Cyrtodactylus as delimited here.

The intermedius group is composed of at least 10 generally allopatric and ecologically diverse nominal species (Fig. 3) that range across hilly terrain from eastern Thailand to southeastern Vietnam, including Koh Rong Island of Cambodia and Phu Quoc and Hon Tre islands of Vietnam (Murdoch et al. 2019; Grismer et al. 2020b; Fig. 16). The group’s taxonomic and ecological diversity is centered in the Cardamom Mountains of southern Cambodia and is represented by terrestrial species (C. thylacodactylus), granite cave species (C. hontreensis), karst-adapted species (C. laangensis), and habitat generalists (e.g. C. kohrongensis) (Fig. 17). The group was previously considered a single species, C. intermedius, until integrative taxonomic analyses demonstrated it is composed of at least 10 species (Murdoch et al. 2019; Grismer et al. 2020b). There are potentially six undescribed species—sp. HLM 0360 from Chanthaburi, Thailand, cf. thylacodactylus KT013138 from O’Lakemas, Cambodia, cf. intermedius HLM 0362 from Khao Yai, Thailand, cf. intermedius GU550710 from Sakaerat, Thailand, cf. intermedius KT013117 from Sa Kaeo, Thailand, and sp. incertae sedis 2 KT013114 from Kirirom, Cambodia (Fig. 3). An additional population from the isolated mountainous region of Phnom Kulen National Park, Cambodia reported as C. intermedius (Geissler et al. 2019) is also a candidate for being a new species. All of these populations are currently being examined by various combinations of authors. Murdoch et al. (2019) and Grismer et al. (2020b) did not consider C. hontreensis from Hon Tre Island, Vietnam as part of the intermedius group but only as a distantly related and strongly supported sister species. It is included as part of the intermedius group here.

Figure 16. 

Distribution of the intermedius, oldhami, and pulchellus species groups of Cyrtodactylus as delimited here and C. tigroides.

Figure 17. 

Examples of the Cyrtodactylus intermedius group. A. C. auralensis from Kampong Speu Province, Cambodia. Photo by L. Lee Grismer. B. C. laangensis from Kampot Province, Cambodia. Photo by Jeremy Holden. С. C. kohrongensis from Koh Rong Island, Koh Kong Province, Cambodia. Photo by L. Lee Grismer. D. C. hontreensis from Hon Tre Island, Kien Giang Province, Vietnam. Photo by L. Lee Grismer.

The irregularis group (Fig. 18) is the largest species group that includes at least 22 nominal, generally allopatric species, of which 20 are included in the present study, along with 11 unnamed lineages (Fig. 3). The group’s distribution is centered in central and southern Vietnam and extends to adjacent regions in easternmost Cambodia and southeast Laos (Nazarov et al. 2012; Nguyen et al. 2013; Neang et al. 2020; Ostrowski et al. 2020; Fig. 9). The group was previously considered to be a single species, C. irregularis (Smith 1921), until a number of studies demonstrated its unprecedented diversity with 20 new species described within the last 14 years (Nguyen et al. 2013; Neang et al. 2020; Ostrowski et al. 2020). This analysis reveals at least 11 more lineages corresponding to potentially undescribed species and taxonomic investigations on these lineages are currently underway by various authors. Cyrtodactylus irregularis was described by Smith (1921) from Cam Ly River’s valley near Da Lat (Lam Dong Province, Vietnam). After its description, the name of C. irregularis was applied to all populations of Cyrtodactylus from the Annamites for nearly a century. There is still some uncertainty as to which lineage among the recently reported populations of the C. irregularis group in the Langbian Plateau corresponds to true C. irregularis. Nazarov et al. (2012) argued that specimens of Cyrtodactylus from Rung Tong Da Lat (Lac Xuan Commune) and Nui Chua Mount (environs of Da Lat) are morphologically most similar to and located in the vicinity of the true C. irregularis s. str. based on Smith (1921)—an issue which is still being investigated. Thus, the use of С. cf. irregularis is applied here. This species is strongly supported (100/1.00) as the sister species of C. bidoupimontis in Nazarov et al. (2012) and here.

Figure 18. 

Examples of the Cyrtodactylus irregularis group. A. C. cryptus from Quang Binh Province, Vietnam. Photo by Thomas Ziegler. B. C. sangi from Ninh Thuan Province, Vietnam. Photo by Sang Ngoc Nguyen. С. C. phnomchiensis from Kampong Thong, Cambodia. Photo by Thy Neang. D. C. takouensis from Binh Thuan Province, Vietnam. Photo by L. Lee Grismer.

The absence of the enlarged subcaudals is considered to be characteristic for all irregularis group members except C. caovansungi, C. kingsadai, and C. takouensis (Orlov et al. 2007, Ngo and Bauer 2008, Ziegler et al. 2013). This diverse group occupies a wide range of habitats. Some are forest-dwelling habitat generalists typically found on the trunks of large trees, branches, tree logs, while others occur on granite boulders (C. culaochamensis, C. cucdongensis, C. kingsadai, C. phuocbinhensis, C. takouensis, and C. yangbayensis). Most irregularis group members inhabit montane forests of the Kon Tum–Gia Lai and Langbian Plateaus in the central and southern portions of the Annamites, also known as the Truong Son Range. A few species are distributed in lowland dipterocarp forests (e.g., C. cattienensis, C. dati, C. huynhi, and C. phnomchiensis). Cyrtodactylus cryptus inhabits limestone evergreen forests in Quang Binh Province in central Vietnam and Khammouane Province in central Laos and C. culaochamensis occurs on a small offshore island in central Vietnam (Ngo et al. 2020). However, C. gialaiensis occurs in the highly modified landscape of a coffee plantation in the Central Highlands of Vietnam (Luu et al. 2017), illustrating the broad range of habitats utilized by members of this group.

The monophyly of the irregularis group has been corroborated in previous phylogenetic analyses, although nodal support values based on CO1 are generally low (Nguyen et al. 2013; Luu et al. 2016; Ostrowski et al. 2020). A previous study using a combination of CO1 and ND2 did not provide strong nodal support for its monophyly (Brennan et al. 2017), while analyses based on ND2 alone gave mixed signals (Brennan et al. 2017; Ngo et al. 2020). In this study, the monophyly of the species group is strongly supported in both analyses (1.00/100) likely due to increased species sampling. In addition, phylogenetic relationships within the group based on CO1 were largely unresolved (Nguyen et al. 2017a; Ostrowski et al. 2020), likely due to the limited read length of this barcoding gene. In contrast, the phylogeny here based on the longer reads of ND2, is well-resolved with nearly all nodes being strongly supported by both analyses (Fig. 3).

The irregularis group is composed of two reciprocally monophyletic subgroups (Fig. 3) corresponding to two main centers of the group’s diversity. Only the northern subgroup, however, is strongly supported in both analyses. The southern subgroup is supported only in the ML analysis (97) and encompasses species occurring on the Langbian Plateau, its foothills, and surrounding lowland dipterocarp forests in southern Vietnam and eastern Cambodia. Only two species of this subgroup (C. gialaiensis and cf. irregularis) are found in the highlands of Gia Lai Province in central Vietnam and Champasak, Laos, respectively. The northern subgroup is strongly supported in both analyses (98/1.00) and primarily composed of species inhabiting Kon Tum–Gia Lai Plateau of the central Annamites, with the exception of C. kingsadai from Phu Yen Province of southern Vietnam, which together with C. cryptus, forms a lineage sister to all other members of the subgroup. Though the recently described C. phumyensis was not included in our analysis, it can be confidently assigned to the irregularis group as it was supported as a sister taxon of C. cucdongensis in Ostrowski et al. (2020). The phylogenetic placement of C. buchardi (David et al. 2004) from southern Laos has not been determined, but based on the absence of enlarged subcaudal scales and its color pattern, it has been hypothesized to belong in the irregularis group (Nazarov et al. 2018). This hypothesis is strengthened by the finding that the irregularis group is the only species group in proximity to the range of C. buchardi in southern Laos (Fig. 9).

According to these data, species diversity within the irregularis group remains underestimated. Most species are narrow-range endemics and a number of cryptic lineages have been revealed within the wide-ranging species such as C. cattienensis (Geissler et al. 2009; Pauwels et al. 2018), the C. ziegleri – C. bugiamapensis complex (Nazarov et al. 2008, 2012; Neang et al. 2020), and C. pseudoquadrivirgatus (Nguyen et al. 2017a) that require further integrative taxonomic assessment. Five unnamed populations representing putative new species are reported here from the highlands of central Vietnam in Gia Lai (HLM 0316, HLM 0365, and HLM 0366), Kon Tum (HLM 0354) and Quang Nam (ZMMU NAP-08781) provinces; two of them (HLM 0316 and HLM 0365) are sympatric in Kon Ka Kinh National Park. This study also revealed two unnamed mitochondrial lineages from Lam Dong Province of southern Vietnam (HLM 0367 and HLM 0368). Additional undescribed species of the irregularis group were reported in a number of recent studies (e.g., Nguyen et al. 2013, 2017a; Pauwels et al. 2018; Neang et al. 2020). All of these populations are currently being examined by various combinations of authors.

Several taxonomic issues within the group warrant clarifications. The status of Cyrtodactylus thuongae (Phung et al. 2014) is in need of verification, as it was regarded as a junior synonym of C. dati by Ngo et al. (2017). The phylogenetic position of C. badenensis is still unclear. It was supported as a member of the group in previous studies (Brennan et al. 2017; Nguyen et al. 2017a; Ostrowski et al. 2020) using CO1. In this study, however, it is recovered as the sister species to the condorensis group in the ML analysis (99) but was not recovered as such in the BEAST analysis. Finally, C. grismeri was assigned to both C. irregularis and C. condorensis groups in the bar-coding tree of Brennan et al. (2017) but was placed in the C. condorensis group by Grismer and Grismer (2017) and here with strong support (100/1.00).

The khasiensis group is composed of 16 nominal species and at least four undescribed species (Fig. 3) that collectively range from northeastern India and Bangladesh eastward to the western edge of the Salween Basin in Myanmar (Fig. 15). Most are morphologically generalized species (Fig. 19) with the exception of C. brevidactylus which is highly terrestrial. The monophyly of the group is strongly supported in both analyses (100/1.00) and the phylogeny indicates it is composed of four sublineages—two each in Arunachal Pradesh/Myanmar and northeast India/Myanmar (Fig. 3). The undescribed species Cyrtodactylus sp. KM255193 from eastern Arunachal Pradesh forms one lineage; C. mombergi from Myanmar and Cyrtodactylus sp. KM255192 from eastern Arunachal Pradesh comprise the other Arunachal Pradesh/Myanmar lineage; C. ayeyarwadyensis, C. guwahatiensis, C. kazirangaensis, C. khasiensis, C. septentrionalis, C. tripuraensis, and C. urbanus constitute the first northeast India/Myanmar clade, with its distribution chiefly in India; and C. aunglini, C. brevidactylus, C. chrysopylos, C. gansi, C. jaintiaensis, C. montanus, C. myaleiktaung, and C. nagalandensis form the second northeast India/Myanmar clade, which includes the majority of the Myanmar species in the C. khasiensis group. The two northeast India/Myanmar clades are well supported sister clades (100/0.96) and are largely distributed south of the Brahmaputra River in northeast India and west of the Salween Basin in Myanmar. Based on the average elevations at which the constituent species are distributed, Agarwal et al. (2014) referred to the predominantly Indian clade as the lowland clade and the other as the mountain clade.

Figure 19. 

Examples of the Cyrtodactylus khasiensis group. A. C. chrysopylos from Shan State, Myanmar. Photo by L. Lee Grismer. B. C. montanus from Tripura state, India. Photo by Ishan Agarwal. С. C. nagalandensis from Nagaland state, India. Photo by Ishan Agarwal. D. C. mombergi from Kachin State, Myanmar. Photo by L. Lee Grismer.

The lateralis group is a small clade with two species—C. durio from Peninsular Malaysia and C. lateralis from Sumatra. (Figs 3, 20). Cyrtodactylus rubidus from the Andaman Islands was recovered as the sister species of this group, but this relationship was only well-supported in the ML analysis (92/0.86), and thus it was excluded although it is likely the relationship is correct. Cyrtodactylus durio and C. lateralis are highly arboreal (Grismer et al. 2010, Harvey et al. 2016) and bear morphological adaptations for arboreality such as a prehensile tail carried coiled (Fig. 21) in an elevated position. Cyrtodactylus rubidus also appears to have a prehensile tail which is often carried in the same manner.

Figure 20. 

Distribution of the lateralis and sworderi species groups of Cyrtodactylus and C. rubidus as delimited here.

Figure 21. 

Examples of the Cyrtodactylus lateralis group. A. C. durio from Kedah State, Peninsular Malaysia. Photo by L. Lee Grismer. B. C. lateralis from Sumatra, Indonesia. Photo by Eric N. Smith.

The lawderanus group (Fig. 22) comprises five nominal species (Fig. 3) that collectively extend from the Western Himalayas in Pakistan eastward through India up to at least the border of Nepal, with a least one species disjunctly distributed on the Tibetan Plateau (Figs 15). The monophyly of the group is strongly supported (99/1.00) in both ND2 analyses with a basal split separating C. tibetanus on the Tibetan Plateau from a strongly supported (100/1.00) western Himalayan clade which includes C. battalensis, C. chamba, C. himalayanus, and C. lawderanus. Cyrtodactylus lawderanus is likely to range into western Nepal. Some of the unsampled species here from the Tibetan Plateau (e.g. C. zhaoermi) are allied to C. tibetanus (Che et al. 2020). In data sets with relatively limited species coverage (Wood et al. 2012, 70 species; Bauer et al. 2013, eight species; Agarwal et al. 2014, 58 species) using essentially the same sequence data (492 base pairs of ND2 and 382 base pairs of RAG1), C. tibetanus was recovered—with varying degrees of nodal support—as the sister species to all other Cyrtodactylus. However, when just the nuclear data (RAG1) of Wood et al. (2012) was re-run in Grismer et al. (2020a), Cyrtodactylus was recovered as paraphyletic as it does in the nuclear tree here—even with the additional species coverage. The monophyly of Cyrtodactylus in the multigene data sets of Wood et al. (2012), Bauer et al. (2013), and Agarwal et al. (2014) is the result of ND2 not the nuclear data and this result remains so even with the vastly expanded species coverage (310 species) here that continues to recover Cyrtodactylus as monophyletic but places C. tibetanus within the lawderanus group. The fluctuating phylogenetic placement of C. tibetanus is likely due to the uninformative nature of the short gene reads along with the lack of sequence data from other Himalayan species. In a separate mito-nuclear analysis using ND2, RAG1, and PDC and 68 species including C. zhaoermi and a potentially undescribed species (C. tibetanus 1), Jing (2020) demonstrated that the latter two and C. tibetanus formed a monophyletic group that is the sister group to all other Cyrtodactylus. That hypothesis is being tested further with an expanded data set composed of 346 species (Grismer et al. in prep.) and if supported, will require the construction of an additional species group—the tibetanus group.

Figure 22. 

Examples of the Cyrtodactylus lawderanus group. A. C. tibetanus from Tibet, China. Photo by Kai Wang. B. C. chamba from Himachal Pradesh state, India. Photo by Ishan Agarwal. С. C. lawderanus from Uttarakhand state, India. Photo by Ishan Agarwal. D. C. zhaoermi from Nyemo, Tibet, China. Photo by Baolin Zhang.

Khan (2003) erected the genus Siwaligekko to accommodate western Himalayan taxa bearing intermediate morphology between Cyrtodactylus and Palearctic naked-toed geckos (see Bauer et al. 2013). Its type species, C. battalensis, makes that name available for this morphologically distinctive clade if subgenera or new genera are ever proposed.

The linnwayensis group is composed of four relatively large (adult SVL > 100 mm), robust, tuberculate, allopatric, karst-adapted species (Figs 3, 23) endemic to the western section of the Shan Plateau of the Mandalay Division and Shan State, Myanmar (Grismer et al. 2018a,b, 2019; Fig. 24). Relationships within this group have remained stable in all previous phylogenetic analyses. Given the extensive amount of unexplored karstic habitat across the vast Shan Plateau and the geographic distance between some of these species in this group (~ 90 km), we believe the species composition of the linnwayensis group is considerably underestimated. We have seen pictures of undescribed species of Cyrtodactylus from various caves throughout the Shan Plateau that resemble linnwayensis group species and expeditions are planned to survey these areas.

Figure 23. 

Examples of the Cyrtodactylus linnwayensis group. A. C. linnwayensis from Shan State, Myanmar. B. C. pinlaungensis from Shan State, Myanmar. C. C. ywanganensis from Shan State, Myanmar. D. C. shwetaungorum from Mandalay Region, Myanmar. Photos by L. Lee Grismer.

Figure 24. 

Distribution of the linnwayensis, peguensis, sadansinensis, sinyineensis, and yathepyanensis species groups of Cyrtodactylus as delimited here.

The malayanus group maybe endemic to Borneo (see below) and composed of at least three nominal species and at least one potentially new species (Figs 3, 7). Although its monophyly is well-supported (100/1.00), its relationships to other species groups are not. In a previous analysis (Davis et al. 2019, 2020), some species of the malayanus group as constituted herein were nested within what is considered here as the well-supported (100/1.00) philippinicus group. However, the taxonomy of those phylogenies had a number of species (C. pubisulcus, C. cavernicolus, C. yoshii, C. malayanus, and C. consobrinus) occurring in multiple places throughout the tree rendering them polyphyletic and making comparisons with this tree not possible. Current research (Grismer et al. in progress) indicates that one of the species, C. consobrinus which also ranges throughout Peninsular Malaysia (Grismer 2011) is a species complex (Fig. 25) and members of this complex belong in both the malayanus and philippinicus groups.

Figure 25. 

Examples of the Cyrtodactylus malayanus group. A. C. malayanus from Sabah State, East Malaysia. Photo by Ruchira Somaweera. B. С. cf. consobrinus from Johor State, Peninsular Malaysia. Photo by L. Lee Grismer. С. C. consobrinus from the type locality in Sarawak State, East Malaysia. Photo by L. Lee Grismer. D. С. cf. consobrinus from Sarawak State, East Malaysia. Photo by Nikolay A. Poyarkov. E. С. cf. consobrinus from Pahang State, Peninsular Malaysia. Photo by L. Lee Grismer. F. С. cf. consobrinus from Perak State, Peninsular Malaysia. Photo by Evan S. H. Quah.

The marmoratus group (Fig. 26) is composed of at least three nominal species (two of which are analyzed here) and six potentially undescribed species (O’Connell et al. 2019; Riyanto et al. 2015) that range from New Guinea westward across the Lesser Sundas and Java, to parts of southern and western Sumatra (Figs 3, 27). The group contains several undescribed species from Java and Sumatra (KR921697, KR921699, KR921689, KR921720, and HLM 0371) and ongoing research is describing many of these (Riyanto in prep). However, it is certain that additional species remain undiscovered across the myriad islands between Java and New Guinea.

Figure 26. 

Examples of the Cyrtodactylus marmoratus group. A. C. papuensis from the Western Province, Papua New Guinea. Photo by Stephen Richards. B. C. marmoratus from Java. Photo by Eric M. Smith. С. C. papuensis from the Timika Province, Papua New Guinea. Photo by Stephen Richards. D. С. cf. papuensis from Papua Province. Indonesia. Photo by Stephen Richards.

Figure 27. 

Distribution of the marmoratus species group of Cyrtodactylus as delimited here.

The oldhami group contains seven nominal species and three potentially new species represented here (Fig. 3, 28). It is essentially endemic to the Thai-Malay Peninsula of southern Thailand and Myanmar with only C. saiyok reaching Sai Yok, Kanchanaburi Province just north of the Peninsula (Panitvong et al. 2014; Fig. 16). The taxonomy of C. oldhami is problematic in that this species is polyphyletic in the tree and preliminary investigations of a large series show considerable variation in color pattern throughout its range, including a number of islands off the west coast of Thailand. This species was previously only known from south of the Isthmus of Kra but a specimen in this analysis (С. cf. oldhami HLM 0307) comes from considerably farther north at Suan Phueng, Ratchaburi Province at the northern end of the Thai-Malay Peninsula. Similarly, the taxonomy of C. zebraicus is also in a state of flux and current investigations from populations throughout its range south of the Isthmus of Kra and adjacent east coast islands have revealed considerable morphological variation (Grismer et al. in prep.). Reports of C. zebraicus from northern Peninsular Malaysia remain unconfirmed (see Grismer 2011).

Figure 28. 

Examples of the Cyrtodactylus oldhami group. A. C. oldhami from Phuket Island, Thailand. Photo by L. Lee Grismer. B. C. zebraicus from Krabi Province, Thailand. Photo by Parinya Pawangkhahant. С. C. sanook from Chumphon Province, Thailand. Photo by Montri Sumontha. D. C. thirakhupti from Surat Thani Province, Thailand. Photo by L. Lee Grismer.

The peguensis group (Fig. 29) is composed of 11 nominal species and at least one undescribed species (Fig. 3) and extends from the eastern Himalayas of India bordering Bhutan and Nepal, eastward to Myanmar across the Ayeyarwady Basin to the western edge of the Shan Plateau (Fig. 24). Although the monophyly of the group was recovered in both analyses, only in the ML analysis was it strongly supported (97/0.73), and as such deviates from the criteria used to construct the other species groups except the sermowaineis species group (see below). The other option would have been to combine the fasciolatus, peguensis, and khasiensis groups into one group (Fig. 3) but we elected to emphasize the independence of these three clades. The group is composed of two Burmese lineages and one Indian lineage. Cyrtodactylus russelli and C. slowinskii compose the northern Burmese lineage and C. annandalei, C. pyadalinensis, C. meersi, C. nyinyikyawi, C. myintkyawthurai, C. pyinyaungensis, and C. peguensis compose the southern Ayeyarwady Basin lineage. Cyrtodactylus bhupathyi, C. gubernatoris and an undescribed species from western Arunachal Pradesh form the Indian or Eastern Himalayan lineage and compose the sister lineage to the southern Burmese lineage (Fig. 3).

Figure 29. 

Examples of the Cyrtodactylus peguensis group. A. C. bhupathyi from West Bengal state, India. Photo by Ishan Agarwal. B. C. pyinyaungensis from Mandalay region, Myanmar. Photo by L. Lee Grismer. С. C. russelli from Kachin State, Myanmar. Photo by L. Lee Grismer. D. C. peguensis from Bago Region, Myanmar. Photo by L. Lee Grismer.

The philippinicus group is composed of at least 17 nominal species (13 included here) and at least five undescribed species (Fig. 3) that are predominantly distributed across the Philippine Archipelago (nine species) and Borneo (six species), with an additional species occurring on the Thai-Malay Peninsula, and another on Pulau Aur off the southeast coast of Peninsular Malaysia (Fig. 7). Of the 17 recognized species comprising this group, the majority are single island (or geological platform) endemics—the exceptions being C. consobrinus (Borneo, Thai-Malay Peninsula, and Singapore), and three Philippine species (C. annulatus, C. jambangan, and C. philippinicus) that are widely distributed across various insular components of that archipelago (Siler etal. 2010, Welton et al. 2009, 2010). To date, none of these species are known to occur in sympatry, and species occurring on the same island (e.g. Borneo or Mindanao) are endemic to single mountains (C. baluensis on Mt. Kinabalu, Borneo Island) or unique geological components of aggregate islands (C. agusanensis on eastern Mindanao Island). While it remains a possibility that widespread species in this group are indeed just that, additional survey efforts and closer examination of allopatric populations of such species continue to document previously unrealized taxonomic diversity. Indeed, a number of populations currently ascribed to C. philippinicus are currently under investigation, and likely warrant specific designation (Wood and Welton, in prep; R. Brown pers. comm.). Similarly, the widespread C. consobrinus is currently being scrutinized for novel taxonomic diversity across its range (Grismer et al. in prep).

Phylogenetically, the philippinicus group comprises three major well-supported mitochondrial lineages, the combination of which is inferred as sister to the basally divergent Cyrtodactylus pubisulcus (Fig. 3). These three clades correspond to 1) a Bornean radiation (C. baluensis, C. ingeri, and C. yoshii) sister to at least three southern Philippine taxa (C. annulatus, C. jambangan, and C. tautbatorum); 2) a single Philippine taxon (C. redimiculus) sister to at least three Sundaic species (C. consobrinus, C. aurensis, and C. muluensis); and 3) an exclusively Philippine clade (C. agusanensis, C. gubaot, C. mamanwa (not in this study), C. philippinicus, and C. sumuroi). Worth noting, is that the topology inferred here differs from those recovered in previous studies that included multiple members of the group (Brennan et al. 2017; Davis et al. 2020; Nielsen and Oliver 2017; Siler et al. 2010; Welton et al. 2010a,b; Wood et al. 2012), likely due to increased taxon sampling and the loci utilized. Though the relationships between Philippine and Sundaic taxa is unsurprising, the topology inferred from mitochondrial data indicates multiple dispersal events between the two faunal regions, yielding the Philippine assemblage of species paraphyletic. The topological patterns recovered here highlight the importance of Palawan Island (Philippines) in the biogeographical history of the philippinicus group. Both major lineages comprising Philippine and Sundaic taxa include one of the two species of Cyrtodactylus that are endemic to Palawan (C. redimiculus or C. tautbatorum). In combination with the geographical position of Palawan being nestled between Borneo and the remainder of the Philippine Archipelago, it is perhaps unsurprising that this island would serve as a stepping-stone in the evolution and historical biogeography of this group.

Phenotypically, the philippinicus group might be considered relatively unremarkable, with the majority of species exhibiting cryptic coloration consisting of brown and tan earth tones—some species exhibit dark transverse bands on the trunk while others have spots or longitudinal stripes overlain on a lighter ground color (Fig. 30). Exceptional species in this group include C. consobrinus, which often exhibits a nearly black ground color overlain with well-defined, thin yellow-gold transverse bands and C. jambangan, which has yellow-gold supraocular scales and canthal stripes.

Figure 30. 

Examples of the Cyrtodactylus philippinicus group. A. C. annulatus from Samar Island, Philippines. Photo by Cameron D. Siler. B. Cyrtodactylus sp. nov. from Lubang Island, Philippines. Photo by Cameron D. Siler. С. C. aurensis from Aur Island, Johor State, Peninsular Malaysia. Photo by L. Lee Grismer. D. C. baluensis from Sabah, East Malaysia. Photo by Steve Wilson.

Taxonomic work on this group has predominantly been focused in the Philippine Archipelago, where more than half of the recognized species have been described since the turn of the century. These works have been the result of a combination of renewed scrutiny of supposed widespread species, coupled with more comprehensive sampling across a number of species’ ranges stemming from contemporary field surveys. As noted above, it is without doubt that additional species from this group will be described in the coming years, serving to increase our knowledge about the evolution and diversification of not only Cyrtodactylus, but the faunal communities to which these species belong.

The pulchellus group is endemic to the southern one-half of the Thai-Malay Peninsula of Thailand and Peninsular Malaysia, ranging from the Isthmus of Kra to southern Peninsular Malaysia (Fig. 16). The group was previously considered a single species, C. pulchellus, until integrative taxonomic analyses demonstrated that it is a monophyletic lineage composed at least 17 nominal species (Grismer et al. 2012a, 2014a; Sumontha et al. 2012; Quah et al. 2019; Wood et al. 2020a) of which 16 are presented here (Figs 3, 31). The phylogenetic relationships of C. phuketensis from Phuket Island, Thailand have not been determined but it has been hypothesized based on morphology and color pattern, that it is closest to C. macrotuberculatus (Sumontha et al. 2012) if not synonymous. In Grismer et al. (2012a, 2014a, 2016b), Quah et al. (2019), and Wood et al. (2020a), the karst clade—most recently composed of C. astrum, C. dayangbuntingensis, C. langkawiensis, and C. lekaguli—was recovered as the sister lineage to a clade containing the remaining species. In this analysis, the karst clade is nested within the group but with poor support (61/0.49). Additionally, C. sharkari from a lowland karstic region does not appear to be genetically distinct from C. trilatofasciatus from an upland granite habitat. A genomic data set for this group is currently being constructed (Wood et al. in prep.). As new populations from unexplored karstic regions are discovered, the number of species in this group will increase substantially (Wood et al. in prep).

Figure 31. 

Examples of the Cyrtodactylus pulchellus group. A. C. dayangbuntingensis from Tuba Island, Kedah State, Peninsular Malaysia. Photo by Evan S. H. Quah. B. C. trilatofasciatus from Pahang State, Peninsular Malaysia. Photo by L. Lee Grismer. С. C. evanquahi from Kedah State, Peninsular Malaysia. Photo by Evan S. H. Quah. D. C. bintangrendah from Perak State, Peninsular Malaysia. Photo by Evan S. H. Quah.

The sadansinensis group is composed of three nominal allopatric karst-adapted species endemic to small limestone hills in the Salween Basin of southern Myanmar (Grismer et al. 2018b; Fig. 32). This group is the strongly supported (100/1.00) sister lineage to a large clade composed of the yathepyanensis, oldhami, sinyineensis, chauquangensis groups, and C. tigroides that collectively range from western Myanmar, through southern China, Thailand, Laos, and northeastern Vietnam (Figs 3, 24). More species are expected to be discovered in this group when the vast number of small, isolated, karstic hills in the Salween Basin are surveyed.

Figure 32. 

Examples of the Cyrtodactylus sadansinensis group. A. C. sanpelensis from Mon State, Myanmar. B. C. pharbaungensis from Mon State, Myanmar. С. C. sadansinensis from Mon State, Myanmar. Photos by L. Lee Grismer.

The sinyineensis group (sec. Grismer et al. 2018b) ranges from the uplands of northwestern Thailand to the lowland karstic archipelagos of the Salween Basin in southeastern Myanmar (Grismer et al. 2018b, 2020c) and is composed of 12 nominal species (Figs 3, 24, 33). The group is divisible into two strongly supported clades (Chomdej et al. 2020; Fig. 3). Clade 1 (100/1.00) is composed of three species (C. sinyineensis, C. taungwineensis, and C. welpyanensis) from the Salween Basin and two species (C. inthanon and C. maelanoi) from upland regions of the Thanon Thong Chai mountain range in northwestern Thailand (Grismer et al. 2020c). Clade 2 (98/1.00) is composed of five species (C. bayinnyiensis, C. dattkyaikensis, C. naungkayaingensis, C. chaunghanakwaensis, and C. dammathetensis) from the Salween Basin and two species from upland regions fringing the northern (C. aequalis) and western (C. amphipetraeus) margins of the Salween Basin (Figs 3, 24). All species in this group are narrow-range endemics (Grismer et al. 2018b, 2020d; Chomdej et al. 2020) and more species belonging to this group are expected to be discovered when the vast number of small, isolated, karstic hills in the Salween Basin and the many unsurveyed mountain tops in western Thailand are explored.

Figure 33. 

Examples of the Cyrtodactylus sinyineensis group. A. C. aequalis from Mon State, Myanmar. Photo by L. Lee Grismer. B. C. naungkayaingensis from Kayin State, Myanmar. Photo by L. Lee Grismer. С. C. taungwineensis from Kayin State, Myanmar. Photo by L. Lee Grismer. D. C. amphipetraeus from Tak Province, Thailand. Photo by Nikolay A. Poyarkov.

The sworderi group is composed of five species endemic to the Thai-Malay Peninsula south of the Isthmus of Kra of southern Thailand (Figs 3, 20). One species, C. quadrivirgatus is a habitat generalist that ranges as far north as the Isthmus of Kra and as far south as Singapore and Sumatra (Grismer 2011). The remaining four species (Fig. 34) are endemic to Peninsular Malaysia. Cyrtodactylus guakanthanensis and C. gunungsenyumensis are karst-adapted species (Grismer et al. 2014b, 2016a), C. tebuensis is an upland habitat generalist (Grismer et al. 2013) and C. sworderi is restricted to lowland swampy areas (Grismer 2011).

Figure 34. 

Examples of the Cyrtodactylus sworderi group. A. C. guakanthanensis from Perak State, Peninsular. B. C. sworderi from Johor State, Peninsular Malaysia. С. C. tebuensis from Terengganu State, Peninsular Malaysia. D. C. quadrivirgatus from Pahang State, Peninsular Malaysia. Photos by L. Lee Grismer.

The triedrus group is composed of 17 nominal species of which 14 are presented here, along with eight undescribed species (Figs 3, 35). This group is endemic to India and Sri Lanka (Fig. 15) and composed of two major clades (Fig. 3). The well-supported (100/1.00) fraenatus clade is endemic to Sri Lanka, and currently hypothesized to contain six nominal species (de Silva and Ukuwela 2020). The first revision of this clade was done by Batuwita and Bahir (2005) where they split the single, widely distributed C. fraenatus (Günther 1864) into six species including five new species, showing that they comprise an endemic radiation of several morphologically differentiated species. Based on morphology, color pattern, and distribution, we hypothesize that the Sri Lankan endemics C. cracens, C. edwardtaylori, and C. subsolanus will also belong to this group. However, the genetic similarity between C. ramboda and C. fraenatus suggests further revision of these species may be necessary even though Batuwita and Bahir (2005) presented morphological differences separating them. Previously, the distribution of Cyrtodactylus in Sri Lanka was restricted to the wet zone, but recently two undescribed species were found near the northern and eastern borders in the dry zone (DWC 2008, see Karunarathna et al. 2019). The fraenatus clade species are large (adult SVL 100–125 mm) scansorial species found on the bark of large tall trees, on large granite boulders, within granite caves, and on abandoned wattle and daub houses (Somaweera and Somaweera 2009).

Figure 35. 

Examples of the Cyrtodactylus triedrus group. A. C. jeyporensis from Andhra Pradesh state, India. Photo by Ishan Agarwal. B. C. triedrus from Central Province, Sri Lanka. Photo by Ishan Agarwal. С. С. cf. speciosus from Tamil Nadu state, India. Photo by Ishan Agarwal. D. C. fraenatus from Central Province, Sri Lanka. Photo by Suranjan Karunarathna. E. C. srilekhae from Karnataka state, India. Photo by Ishan Agarwal. F. C. deccanensis from Maharashtra state, India. Photo by Ishan Agarwal.

The triedrus clade is composed of the remaining 11 nominal species and at least eight undescribed species, and is endemic to peninsular India and Sri Lanka (Agarwal and Karanth 2015). The group is recovered as monophyletic in the ML analysis with strong support (96), while the BEAST analysis recovers a Sri Lankan lineage composed of C. triedrus and two С. cf. triedrus as sister to the C. fraenatus clade with low/moderate support (0.86). Cyrtodactylus triedrus and two closely related undescribed species are endemic to Sri Lanka, while the Indian radiation of the triedrus clade includes the northern Western Ghats C. albofasciatus and C. deccanensis lineages that include two undescribed species, the northern Eastern Ghats C. jeyporensis and the C. nebulosus lineages that includes three undescribed species, and the largely south Indian C. collegalensis lineage that includes C. collegalensis, C. rishivalleyensis, C. speciosus, C. srilekhae, C. varadgirii, the Sri Lankan C. yakhuna, and one undescribed species. Historical records of C. collegalensis from Sri Lanka likely represent additional unnamed lineages of the C. collegalensis lineage. All members of the triedrus clade are largely ground-dwelling in habit and range in size from 50–80 mm SVL; while members of the fraenatus clade are scansorial and are 100–125 mm SVL. Members of the Indian species lack precloacal pores which occur in males of C. triedrus and species in the fraenatus clade (Batuwita and Bahir 2005; SK pers. obs.). Precloacal and femoral pores are also absent from Sri Lankan С. cf. collegalensis and C. yakhuna. The name Geckoella (type species C. triedrus) has been applied to the ground-dwelling members of the triedrus group (e.g. Kluge 1993; Agarwal and Karanth 2015), though the monophyly of Geckoella is recovered only in the ML analyses.

The yathepyanensis group is composed of three nominal, narrow-range, allopatric, karst-adapted species (Fig. 36) found on small limestone hills in the northern Salween Basin of southern Myanmar (Grismer et al. 2018b; Figs 3, 24). All three species are moderately sized (SVL 60—78 mm) gracile species with irregularly shaped dorsal bands (Grismer et al. 2018b). More species belonging to this group are expected to be discovered when the vast number of small, isolated, karstic hills in the Salween Basin are surveyed.

Figure 36. 

Examples of the Cyrtodactylus yathepyanensis group. A. C. linnoensis from Kayin State, Myamar. B. C. sadanensis from Kayin State, Myanmar. С. C. yathepyanensis from Kayin State, Myanmar. Photos by L. Lee Grismer.

The arcanus group is composed of two recently recognized and poorly known species from hill and lower-montane forests along the Central Cordillera in Papua New Guinea (Figs 3, 37). Cyrtodactylus arcanus and C. manos are known, respectively, from two male and one female voucher specimens but appear to share small-to-moderate size and a complex dorsal pattern of numerous (6–11) transverse blotches or bands (Oliver et al. 2012, 2019). Cyrtodactylus manos (Fig. 38) is only known from lower-montane forests on the karst basement in Southern Highlands Province, on the southern versant of New Guinea. Cyrtodactylus arcanus is known from at least two sites on the northern versant in New Guinea in Madang and Jiwaka Provinces. At both sites, however, specimens were brought in by locals; thus, as far as we are aware, this species has never been seen or captured in situ by herpetologists (Oliver et al. 2012, Oliver and Switak 2019). This species group provides an example of a divergent lineage of Cyrtodactylus that is composed entirely of species described in the last ten years.

Figure 37. 

Distribution of the arcanus and novaeguineae species groups of Cyrtodactylus as delimited here.

Figure 38. 

Example of the Cyrtodactylus arcanus group: C. manos from Southern Highlands Province, Papua New Guinea. Photo by Stephen Richards.

The capreoloides group comprises three species occurring in hill and lower-montane forests on the southern versant of the Central Cordillera extending from Gulf Province into West Papua (C. capreoloides, C. medioclivus and C. tanim), one species from the Huon Peninsula (C. minor), and one species from the northern coastal ranges of Papua New Guinea and West Papua (C. boreoclivus) (Fig. 39). Species in this group are morphologically heterogenous in size, coloration and tail scalation (Fig. 40), although males always appear to have a tripartite pore arrangement (Oliver et al. 2012; Oliver and Richards 2012; Nielsen and Oliver 2017). Cyrtodactylus tanim is currently the only known Cyrtodactylus from New Guinea that shows evidence of morphological specializations associated with living in karst microhabitats (Nielsen and Oliver 2017). Tallowin et al. (2018) placed C. minor in a monophyletic species group on the basis of its biogeographic and phylogenetic divergence from other members of the capreoloides species group. Contrary to this, it is placed here within an expanded capreoloides group based on the increasing support for the node subtending C. minor and other members of the capreoloides group and to minimize the number of recognized orphaned species. This species group provides another example of a divergent lineage of Cyrtodactylus composed largely of species recently documented. The nominate taxon was described in 2007 (Rösler et al. 2007), with three additional species described only in the ensuing decade. A small number of specimens that are also likely members of this species group from the Central Cordillera in West Papua (e.g., around Wamena) are held in museums (P. Oliver, pers. obs.); however, the taxonomic affiliations of these specimens have not yet been properly investigated.