You are here » home advanced search search results Oligodon saiyok

Oligodon saiyok SUMONTHA, KUNYA, DANGSRI & PAUWELS, 2017

Can you confirm these amateur observations of Oligodon saiyok?

Add your own observation of
Oligodon saiyok »

Find more photos by Google images search: Google images

Higher TaxaColubridae, Colubrinae, Colubroidea, Caenophidia, Alethinophidia, Serpentes, Squamata (snakes) 
Subspecies 
Common NamesThai: Ngu Ngod Sai Yok
English: Sai Yok Kukri Snake
French: Oligodon de Saï Yok
German: Sai Yok Kukrinatter 
SynonymOligodon saiyok SUMONTHA, KUNYA, DANGSRI & PAUWELS 2017 
DistributionW Thailand (Kanchanaburi)

Type locality: Wat Tham Benjarat Nakhon (= Benjarat Nakhon Cave Temple), Sai Yok District, Kanchanaburi Province, western Thailand  
Reproductionoviparous 
TypesHolotype: QSMI 1506 (field number MS 469); adult male; collected by K. Kunya, M. Sumontha and S. Dangsri on 7 October 2009 at 18.00. Paratype. QSMI 1507 (field number MS 470), adult female, same locality and collector as holotype. It was found two hours later than the holotype. 
DiagnosisDiagnosis. Oligodon saiyok sp. nov. can be distinguished from all other congeneric species by its maximal known SVL of 626.1 mm, 8 SL, 17-17-15 DSR, 181–187 VEN, single anal, 38–43 SC, 13 MT, a dorsal pattern with 21 or 22 large blotches or rings, and venter with a dense network of subrectangular dark blotches.

Comparisons: The hemipenial structure, as well as the scalation, the dorsal color pattern and the number of maxillary teeth, were used as main criteria to gather Oligodon species of the Indochinese Peninsula and Thailand into several informal groups (Smith 1943; Wagner 1975; David et al. 2008b; Green 2010; Green et al. 2010; Orlov et al. 2010; Jiang et al. 2012; Neang et al. 2012; Neang & Hun 2013; Vassilieva 2015). Because the hemipenes of the holotype of Oligodon saiyok sp. nov. were not everted during its preservation, the hemipenial structure, except its length in situ, are unknown to us. Hemipenial characters are unavailable for a number of other Oligodon species. We consequently provide a comparison of our new species with all Oligodon species found in Thailand, Myanmar, Laos, Cambodia and Vietnam, using morphological and chromatical characters except the hemipenes structure.
Compared to the informal ‘‘Oligodon cinereus group’’, the new species is distinguished from O. albocinctus (Cantor, 1839) by its 17 MSR (vs. 19 or rarely 21), generally lower SC number (38–43 vs. 42–69), 13 (vs. 10–12) MT (O. saiyok sp. nov. also differs from O. amabilis (Günther, 1868), described from the ‘‘Arrakan Hills’’ and regarded by some authors as a synonym of O. albocinctus, by its 17 [vs. 19] MSR, much lower SC number [38–43 vs. 75] and much lower number of dorsal rings [22 vs. 41], cf. the original description by Günther 1868); from O. cinereus cinereus (Günther, 1864) by its blotched or ringed (vs. uniform or reticulate) dorsal pattern, its higher VEN number (181–187 vs. 156–178) and longer hemipenes, reaching the 18th (vs the 14th at most) in situ; from O. cinereus pallidocinctus Bourret, 1934 by its 13 (vs. 11–12) MT, its higher VEN number (181–187 vs. 164–176), its longer hemipenes, reaching the 18th SC (vs the 12th at most) in situ, its 21 or 22 dorsal blotches or rings (vs. 27–34 rings), presence of a chevron in adults (vs. only in young individuals), and its heavily maculated venter (vs. unspotted); from O. cinereus tamdaoensis (Bourret, 1935) by its 13 (vs. 11–12) MT, more SC in males (43 vs. 30– 42) and in females (38 vs. 30–36, cf. David et al. 2011) and longer hemipenes, reaching the 18th SC (vs the 11th at most) in situ; from O. inornatus (Boulenger, 1914) by its ASR and MSR of 17 (vs. 15), higher VEN number (181–187 vs. 169–174), 13 (vs. 11–12) MT, presence (vs. absence) of a chevron, and blotched or ringed pattern (vs. no pattern or with reticulations); from O. joynsoni (Smith, 1917) by its 13 (vs. 11 or 12) MT, one (vs. 2, exceptionally one) anterior temporal, lower VEN number in females (181 vs. 193–200, see Jiang et al. 2012), its blotched or ringed (vs. reticulate) dorsal pattern, and its longer hemipenes, reaching the 18th SC (vs the 14th at most) in situ (we agree with David et al. 2011 in the re-identification as O. joynsoni of the Thai records of O. cinereus multifasciatus Jan and O. cinereus swinhonis Günther, 1864 by Taylor 1965); from O. macrurus (Angel, 1927) by its 13 (vs. 14 or 15) MT, much higher VEN number (181–187 vs. 139–162), lower SC number (38–43 vs. 45–94), and much shorter hemipenes, reaching the 18th SC at most (vs. 28th) in situ; from O. nagao David, Nguyen, Nguyen, Jiang, Chen, Teynié & Ziegler, 2012 by its 13 (vs. 9 or 10) MT with last 2 (vs. 3) enlarged, and 21 or 22 blotches or rings on dorsum (vs. 27–37 blotches); from O. purpurascens by its 17 (vs. 19 or 21) MSR, 13 (vs. 9 or 10) MT, one (vs. 2) anterior temporals, and 21 or 22 rings or blotches on dorsum (vs. 10–18 blotches); and from O. splendidus (Günther, 1875) by its 13 (vs. 10 or 11) MT, 17 (vs. 21) MSR, and 21 or 22 blotches or rings on dorsum (vs. 14–17 blotches). Based on its dorsal color pattern and its scalation, we suggest that Oligodon saiyok sp. nov. is a member of the ‘‘O. cinereus group’’, possibly more closely related to O. nagao with which it shares a similar dorsal pattern (at least for the males known in both species) and karst-dwelling habits.
Within the ‘‘Oligodon cyclurus group’’, O. saiyok sp. nov. is distinguished from O. cattienensis Vassilieva, Geissler, Galoyan, Poyarkov, Wayne Van Devender & Böhme, 2013 by its higher number of VEN (181–187 vs. 167–178) and SC (38–43 vs. 31–35), 13 (vs. 8–10) MT whose last 2 (vs. 3) are enlarged, and 21 or 22 rings or blotches on dorsum (vs. 24–35 blotches); from O. chinensis (Günther, 1888) by its lower SC number (38–43 vs. 47–64), 13 (vs. 9 or 10) MT, and longer hemipenes, reaching the 18th SC (vs. 12–13th) in situ; from O. condaoensis Nguyen, Nguyen, Le & Murphy, 2016, endemic to Hon Ba Island in southern Vietnam, by its higher number of VEN (181–187 vs. 168–176) and SC (38–43 vs. 33–37), longer hemipenes, reaching the 18th SC (vs. 13–14th) in situ, and presence (vs. absence) of dorsal rings or blotches; from O. cyclurus (Cantor, 1839) by its 13 (vs. 9 or 10) MT, ASR and MSR of 17 (vs. 19), and higher VEN number (181–187 vs. 160–173); from O. fasciolatus (Günther, 1864) by its 17 ASR (vs. 21 or 23), 17 MSR (vs. 21) and 15 PSR (vs. 17); from O. formosanus (Günther, 1872) by its 13 MT (vs. 10 or 11), 17 ASR and MSR (vs. 19), and the absence (vs. presence) of dorsal stripes (see also patterns of live individuals illustrated by Huang et al. 2011); from O. kampucheaensis Neang, Grismer & Daltry, 2012 by its 17 ASR and MSR (vs. 15), higher VEN number (181–187 vs. 164), 13 MT (vs. 11), much longer hemipenes, reaching the 18th SC (vs. 11th) in situ, and 21 or 22 rings or blotches on dorsum (vs. 17 rings); from O. ocellatus (Morice, 1875) by its 17 ASR and MSR (vs. 19), higher VEN number (181–187 vs. 152–180), and 13 (vs. 9–11) MT; from O. saintgironsi David, Vogel & Pauwels, 2008 by its ASR of 17 (vs. 19), 13 (vs. 10–12) MT with last 2 (vs. 3) enlarged, lower SC number (38–43 vs. 53–59), and much shorter hemipenes, reaching in situ at most the 18th (vs. 28th) SC.
Compared with species of the ‘‘Oligodon taeniatus group’’, largely present in Thailand, O. saiyok sp. nov. differs from O. barroni (Smith, 1916) by its much larger size (maximum TL 718.3 vs. 401 mm), much higher VEN number (181–187 vs. 136–160), and longer hemipenes, reaching the 18th SC (vs. 10–12th) in situ; from O. deuvei David, Vogel & van Rooijen, 2008 by its larger size (maximum TL 718.3 vs. 530 mm), much higher VEN number (181–187 vs. 140–155), longer hemipenes, reaching the 18th SC (vs. 12th) in situ, and absence (vs. presence) of dorsal stripes; from O. moricei David, Vogel & van Rooijen, 2008 by its much larger size (maximum TL 718.3 vs. 442 mm), higher VEN number (181–187 vs. 175), and absence (vs. presence) of dorsal stripes; from O. mouhoti (Boulenger, 1914) by its much larger size (maximum TL 718.3 vs. 339 mm), much higher VEN number (181–187 vs. 145–163), 13 MT (14–16) and absence (vs. presence) of dorsal stripes; from O. pseudotaeniatus David, Vogel & van Rooijen, 2008 by its much larger size (maximum TL 718.3 vs. 320 mm), much higher VEN number (181– 187 vs. 137–156), longer hemipenes, reaching the 18th SC (vs. 14–16th) in situ, 13 (vs. 15) MT, and absence (vs. presence) of dorsal stripes; and from O. taeniatus (Günther, 1861) by its much larger size (maximum TL 718.3 vs. 447 mm), higher VEN number (181–187 vs. 142–165), 17 ASR and MSR (vs. 19), longer hemipenes, reaching the 18th SC (vs. 14–16th) in situ, 13 (vs. 14–18) MT, and absence (vs. presence) of dorsal stripes. Oligodon saiyok sp. nov. is distinguished from O. arenarius Vassilieva, 2015 by its much larger size (maximum TL 718.3 vs. 389 mm), much higher VEN number (181–187 vs. 131–144), 13 (vs. 6–8) MT, presence (vs. absence) of blotches or rings on dorsum, and heavily maculated (vs. immaculate) belly.
Oligodon saiyok sp. nov. differs from the ‘‘O. cruentatus-planiceps-theobaldi-torquatus group’’: from O. cruentatus (Günther, 1868) by its higher VEN number (181–187 vs. 148–173), single (vs. divided) anal plate, 13 (vs. 14–16) MT and absence (vs. presence) of dorsal stripes; from O. planiceps (Boulenger, 1888) by its 17 (vs. 13) MSR, 8 (vs. 5) SL, much higher VEN number (181–187 vs. 132–145), higher SC number (38–43 vs. 22–27), single (vs. divided) anal, and 13 (vs. 10) MT; from O. theobaldi (Günther, 1868) by its 13 (vs. 15 or 16) MT, single (vs. divided) anal, and a blotched or ringed (vs. reticulated) dorsum; and from O. torquatus (Boulenger, 1888) by its higher number of VEN (181–187 vs. 144–169) and SC (38–43 vs. 25–34), 17 (vs. 15) MSR, single (vs. divided) anal, 13 (vs. 15 or 16) MT, a blotched or ringed (vs. reticulated) dorsum and the absence (vs. presence) of dorsal stripes.
The new species differs from Oligodon annamensis Leviton, 1953 by the presence (vs. absence) of a LOR, two (vs. one) PosOc, 8 (vs. 6) SL, more VEN (181–187 vs. 159–170), and 17 (vs. 13) MSR; from O. catenatus (Blyth, 1854) by the presence (vs. absence) of a LOR and internasals, 8 (vs. 6) SL, 17 (vs. 13) MSR, single (vs. divided) anal, and absence (vs. presence) of dorsal stripes; from O. dorsalis (Gray, 1835) by its 17 (vs. 15) MSR, single (vs. divided) anal, and absence (vs. presence) of dorsal stripes; from O. eberhardti Pellegrin, 1910 by its 8 (vs. 6) SL, 17 (vs. 13) MSR, single (vs. divided) anal, and 13 (vs. 7) MT; from O. hamptoni Boulenger, 1918 by its 17 (vs. 15) MSR, 8 (vs. 5) SL, single (vs. divided) anal, higher number of VEN (181–187 vs. 160–175) and of SC (38–43 vs. 30–32), and the absence (vs. presence) of dorsal stripes; from O. jintakunei Pauwels, Wallach, David & Chanhome, 2002, still known only by its holotype from Krabi Province, by its distinct (vs. fused) internasals and prefrontals, 17 (vs. 15) MSR, lower number of VEN (181–187 vs. 189) and SC (38–43 vs. 46), single (vs. divided) anal, 13 (vs. 6) MT, and heavily maculated (vs. immaculate) belly; from O. lacroixi Angel & Bourret, 1933 by the presence (vs. absence) of a LOR and internasals, 8 (vs. 5) SL, 17 (vs. 15) MSR, higher number of VEN (181–187 vs. 162–178) and SC (38–43 vs. 25–33), single (vs. divided) anal, 13 (vs. 8–12) MT, and the absence (vs. presence) of dorsal stripes; and from O. mcdougalli Wall, 1905 by the presence (vs. absence) of a LOR, 17 (vs. 13) MSR, lower VEN number (181–187 vs. 199), anal single (vs. divided), and the absence (vs. presence) of dorsal stripes.
Oligodon saiyok sp. nov. increases the already exceptionally high number of squamates endemic to Sai Yok District, still unexplained to date: Cnemaspis huaseesom Grismer, Sumontha, Cota, Grismer, Wood, Pauwels & Kunya, 2010, Cyrtodactylus saiyok Panitvong, Sumontha, Tunprasert & Pauwels, 2014 and C. tigroides Bauer, Sumontha & Pauwels, 2003, Dixonius hangseesom Bauer, Sumontha, Grossmann, Pauwels & Vogel, 2004, Gekko nutaphandi Bauer, Sumontha & Pauwels, 2008, and Trimeresurus kanburiensis Smith, 1943 (see David et al. 2004). Apiwathnasorn et al. (2011: 1406) indicated that Wat Benjarat Cave is a popular touristic attraction. Like a number of other Thai endemic reptiles living in cave or their direct surroundings, Oligodon saiyok sp. nov. has to cope with a high degree of human disturbance (Pauwels et al. 2016), in this case due to religious activities and tourism. We have never encountered Oligodon saiyok sp. nov. in the pet trade, and we do not believe that it is currently under any specific conservation threat besides its habitat’s degradation. 
CommentSyntopy: Cyrtodactylus cf. peguensis, C. tigroides, Dixonius hangseesom, Gekko gecko, G. nutaphandi, Trimeresurus kanburiensis. 
EtymologyThe specific epithet is an invariable noun in honor of the administrative district where the type- locality lies. 
References
  • SUMONTHA, MONTRI; KIRATI KUNYA, SIRIWAT DANGSRI & OLIVIER S. G. PAUWELS 2017. Oligodon saiyok, a new limestone-dwelling kukri snake (Serpentes: Colubridae) from Kanchanaburi Province, western Thailand Zootaxa 4294 (3): 316–328 - get paper here
 
External links  
Is it interesting? Share with others:

As link to this species use URL address:

http://reptile-database.reptarium.cz/species?genus=Oligodon&species=saiyok

without field 'search_param'. Field 'search_param' is used for browsing search result.



Please submit feedback about this entry to the curator