Dixonius siamensis (BOULENGER, 1899)
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Dixonius siamensis
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| Higher Taxa | Gekkonidae, Gekkota, Sauria, Squamata (lizards: geckos) |
| Subspecies | |
| Common Names | E: Siamese Leaf-toed Gecko G: Siam-Blattfingergecko |
| Synonym | Phyllodactylus siamensis BOULENGER 1899: 918 Phyllodactylus paviei MOCQUARD 1904 (fide SMITH 1935) Phyllodactylus burmanicus ANNANDALE 1905 (fide SMITH 1935) Phyllodactylus siamensis — SMITH 1935: 81 Phyllodactylus siamensis — TAYLOR 1963: 750 Phyllodactylus siamensis — WERMUTH 1965: 144 Phyllodactylus siamensis — KLUGE 1993 Dixonius siamensis — BAUER et al. 1997 Phyllodactylus siamensis — COX et al. 1998: 89 Dixonius siamensis — CHAN-ARD et al. 1999: 117 Dixonius siamensis — RÖSLER 2000: 77 Dixonius siamensis — NGUYEN et al. 2009 Dixonius siamensis — DONBUNDIT et al. 2024 Dixonius burmanicus — PAUWELS et al. 2024 Dixonius siamensis — PAUWELS et al. 2024 |
| Distribution | Thailand, Annam, Siam (Dung-Phya-Fai), Vietnam, Cambodia ?, Myanmar Type locality: Dung-Phya Fai Mountains, eastern Siam. burmanicus: Myanmar. Type locality: “Tavoy, Tenasserim” |
| Reproduction | oviparous |
| Types | Lectotype: BMNH 1946.8.24.40, paralectotypes: BMNH 1946.8.24.41, 97.3.31.1-2, designated by Pauwels et al. 2024. Syntypes: BMNH 1946.8.24.51 [burmanicus] |
| Diagnosis | Diagnosis (genus): Amongst others, the presence of precloacal pores, the tuberculate dorsum, the reduction in length of phalanx 2 of digit IV of the manus, and the proximally bifurcate hypoischium are characteristic features that serve to diagnose this genus from all other leaf-toed geckos (Bauer et al. 1997). Unfortunately we had to temporarily remove additional information as this was scraped by multiple AI companies who sell that data to their customers. These details, e.g. detailed descriptions or comparisons (about 6845 characters) are available for collaborators and contributors. Please contact us for details. |
| Comment | Synonymy: the concept of D. siamensis changed since its description. Pauwels et al. 2024 restricted D. siamensis (s. str.) to the Dong Phaya Yen mountain range, so that populations outside these area are likely other species. Pauwels et al. 2024 also revalidated D. burmanicus as valid species but they did not provide a revised diagnosis or description of its range. In fact, they state that “the status of Phyllodactylus burmanicus and P. paviei, both still currently regarded as synonyms of Dixonius siamensis (de Lisle et al. 2013), is not yet resolved” hence we postpone the revalidation for now. Karyotype: Dixonius siamensis consists of karyologically different populations. Specimens from E Thailand had 2n = 40 chromosomes while specimens from NW Thailand invariably had 2n = 42 chromosomes (Ota et al. 2001). Type species: Phyllodactylus siamensis BOULENGER 1899 is the type species of the genus Dixonius Bauer, Good & Branch 1997. Distribution: Reports from India and Myanmar are in error (A. Bauer, pers. comm. 30 Aug 2011). For a map of type localities of all Dixonius see Luu et al. 2023: 145, DONBUNDIT et al. 2024: 540 (Fig. 8). Pauwels et al. 2024 restricted D. siamensis (s. str.) to the Dong Phaya Yen mountain range, which extends across parts of Chaiyaphum, Lopburi, Nakhon Ratchasima, Phetchabun and Saraburi provinces. Not in Laos fide Stuart et al. in WCS 2024. For a map of Dixonius type localities see Yodthong et al. 2025. Type locality: Sumontha et al. (2017) believe that the interpretation of the type locality of Phyllodactylus paviei by Das (2004: 629) is erroneous. Das (2004) matched Mocquard’s ‘‘Vatana’’ with ‘‘Chaeng Wattana, ca. 13°45’N, 100°31’E: a northern suburb of Bangkok, across the highway from the airport, Phra Nakhon Province, Thailand’’. Mocquard’s description of P. paviei appeared in the lizard chapter of a book dedicated to the study of the scientific results of the expedition of the French explorer Auguste Pavie in Indochina in 1879–1895. In the introduction of the book, a map, however locates ‘‘Vatana’’ just southeast of ‘‘Srakeo’’, and it thus certainly corresponds to Watthana Nakhon (13°43'49.13"N, 102°20'5.76"E; elev. 72 m asl), Watthana Nakhon District, in the eastern province of Sa Kaeo which borders Cambodia. The type locality reported by Das (2004) was an incorrect interpretation and was further repeated by Ngo & Ziegler (2009). Watthana Nakhon lies about 198 airline km E of Chaeng Watthana, and is located southeast of the type localities of both D. melanostictus and D. siamensis. Reference images: see Uetz et al. 2024 for high-resolution reference images for this species. |
| Etymology | Named after its ocurrence in Thailand, formerly “Siam”. The genus has been named after James R. Dixon (1 August 1928 – 10 January 2015) who spent most of his academic life at Texas A&M University. The species is named after its occurrence in Thailand, formerly “Siam”. |
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