Bioacoustics of Trimeresurus kuiburi

Etymology. The specific epithet is a noun in apposition, invariable, in reference to the administrative district Kui Buri in which the type-locality lies. We suggest the following common names: งูหางแห้มกุย ( Ngu Hang Ham Kui , Thai), Kui Buri Pitviper (English), Trimérésure de Kui Buri (French), and Kui Buri Bambusotter (German). Comparison to other species. The possession of a long papillose hemipenis and a partially fused first supralabial and nasal scale makes of Trimeresurus kuiburi sp. nov. a member of the Trimeresurus group sensu stricto ( Cryptelytrops group sensu Malhotra & Thorpe 2004a ), which currently includes the following 20 species: Trimeresurus albolabris (Gray) , T. andersonii Theobald , T. cantori (Blyth) , T. cardamomensis Malhotra, Thorpe, Mrinalini & Stuart , T. caudornatus Chen, Ding, Vogel & Shi , T. davidi Chandramouli, Campbell & Vogel , T. erythrurus (Cantor) , T. fasciatus (Boulenger) , T. guoi Chen, Shi, Vogel & Ding , T. honsonensis (Grismer, Ngo & Grismer) , T. insularis Kramer , T. kanburiensis Smith , T. labialis Fitzinger in Steindachner, T. macrops Kramer , T. mutabilis Stoliczka , T. purpureomaculatus (Gray) , T. rubeus Malhotra, Thorpe, Mrinalini & Stuart , T. salazar Mirza, Bhosale, Phansalkar, Sawant, Gowande & Patel , T. septentrionalis Kramer and T. venustus Vogel ( David & Vogel 2015 ; Chandramouli et al . 2020 ; Chen et al . 2020a –b; Mirza et al . 2020 ). Among these species, Trimeresurus kuiburi sp. nov. is readily distinguished from the widespread Trimeresurus albolabris , the Andaman and Nicobar Islands endemic T. andersonii , the Nicobar Archipelago endemics T. cantori , T. davidi , T. labialis and T. mutabilis , the Cardamom Mounts endemic T. cardamomensis , the Chinese T. caudornatus , the Indo-Burmese T. erythrurus , the Indonesian Tanahdjampea Island endemic T. fasciatus , the widespread T. guoi , the Vietnamese Hon Son Island endemic T. honsonensis , the Indonesian T. insularis , the Southeast Asian T. macrops , the southern Vietnamese-Cambodian T. rubeus , the Indian T. salazar and the Himalayan T. septentrionalis by its dorsal pattern made of purple-red bands on a green background ( David & Vogel 2000 ; David et al . 2003 ; Grismer et al . 2008 ; Malhotra et al . 2011 ; Vogel et al . 2014 ; Chandramouli et al . 2020 ; Chen et al . 2020 a –b; Mirza et al . 2020 ). Its 19 MSR further separate it from Trimeresurus andersonii (21 MSR), T. cantori (27, 29 or 31), T. cardamomensis (21), T. caudornatus (21), T. davidi (21 or 23), T. erythrurus (23 or 25), T. fasciatus (21), T. guoi (21), T. honsonensis (21), T. insularis (21), T. labialis (21 or 23), T. macrops (21), T. mutabilis (21), T. purpureomaculatus (23–29), T. rubeus (21), T. septentrionalis (21) and most specimens of T. venustus (21, rarely 19). Compared to all members of the Cryptelytrops group, Trimeresurus kuiburi sp. nov. is superficially similar only to T. kanburiensis and T. venustus , two geographically-restricted endemics of western Thailand and the Thai-Malay Peninsula, respectively. The northernmost published record of Trimeresurus venustus was mentioned by Pauwels et al. (2013 ; Figure 9B ) who listed the reptile taxa co-occurring at the type-locality of Cyrtodactylus sanook in Muang District, Chumphon Province . At that time we were not aware of the existence of the Kui Buri population and we did not morphologically examine in detail what we believed to be not more than a northern range extension of Trimeresurus venustus . The males of the Chumphon population, contrary to Trimeresurus kuiburi sp. nov. , do not show a concave but a straight suborbital stripe, and they show a white vertebral dot every 2 to 4 vertebral scales, while male T. kuiburi sp. nov. show a dot every 5 or 6 scales, and typical male T. venustus do not show white dots ( Figure 9A ). In any case, Trimeresurus kuiburi sp. nov. is distinct from Trimeresurus venustus sensu auctorum . A striking pattern difference is the concave shape of the suborbital white stripe in male Trimeresurus kuiburi sp. nov . It is straight and bordering the orbit in males of the northern and southern populations of T. venustus (less contrasted or sometimes not visible in females), as can be clearly seen in photographs published in the original description of T. venustus showing specimens from Thung Song, as well as in Manthey & Grossmann (1997: 411 , one individual from ‘Süd-Thailand’), Chan-ard et al . (1999: 197–198, an individual from Tai Rom Yen National Park in Surat Thani Prov. , and another from Surat Thani Province without locality details, identified as T. kanburiensis ), Gumprecht & Ryabov (2002: 37 , a female from Kanchanadit, Surat Thani Prov. , as T. kanburiensis ), Vogel (2006: 122–123 , five individuals from ‘South Thailand’), Figures 10–11 , and in the museum material we examined (see Appendix). Many other photographs and some drawings of Trimeresurus venustus s.l. were published without any locality information, but none of them showed a convex suborbital stripe, and as far as we know, none of them was illustrating individuals from Prachuap Khiri Khan Province . This includes among others the individuals illustrated by Thumwipat & Nutphand (1982: 140 , identified as T. purpureomaculatus ), Kundert (1984 : Fig. 106, as T. sumatranus ), Lim & Lee (1989: 107 top, as T. purpureomaculatus ), Nabhitabhata (1989: 176 , implicitly as T. kanburiensis ), Cox (1991: 398 , as T. kanburiensis ), Jintakune & Chanhome (1995: 129 , as T. kanburiensis ), Cox et al . (1998: 22 , as T. kanburiensis ), Jintakune (2000: 151 , as T. kanburiensis ), Nutphand (2001: 298–299 , as T. purpureomaculatus ; see David et al . 2004a ), Chan-ard (2002: 127 , as T. kanburiensis ), Sanders et al . (2006 : Supplementary material: Fig. 2b ), Anonymous (2010: 3 , as T. kanburiensis ), Chanhome et al . (2011: 326) , O’Shea (2013: 18) , Chan-ard et al . (2015: 287; individuals from Surat Thani or Nakhon Si Thammarat ), Suteparuk & Vasaruchapong (2016 : Fig. 2 ), Visser (2015 : Figs 610, 612–613, 615–622), Oliveri et al . (2016 : Fig. 7 A-D) and Fuchs et al . (2019) . The latter publication described the medical consequences of the bite by a F2 captive individual of unknown geographic origin; it is stated that this species ( T. venustus ) has 21-21-15 DSR, but these numbers actually come from the internet (http://www.toxinology.com/) and were not verified on the individual in question (J. Fuchs, pers. comm. to OSGP, Oct. 2020 ). T. kanburiensis T. kuiburi sp. nov. T. venustus s.l. Max. known SVL (mm) 582 451 486 Ratio TaL/TL females 0.124–0.139 0.133–0.135 0.137–0.148 Ratio SOL/SOW 1.69–2.19 2.06–3.38 2.33–3.21 IOS 7–9 9–11 8–12 Internasals in contact 0% 100% 45% MSR 19 19 21 (19) SRR 21 to 19 (V) 18–28 16–47 106–111* V males 170–178 164–166 166–181 V females 164–171 SC males 59 63–65 63–72 SC females 41–51 51–53 50–66 Suborbital stripe (males) Straight Concave Straight Dorsum color in life dark olive-brown bands on olive-grayish background red/purple bands on bottle green background red/purple bands on bottle green background White vertebral dots (males) Present, every 3-5 scales Present, every 5-6 scales Absent (or present every 2–4 scales in Chumphon population) Belly background color in life creamy white pale green pale green Lateral dark stripe on ventrals Always present, discon- tinuous, olive-brown Always absent Always present, continuous or discontinuous, red *for the specimens with 21 MSR; for the two specimens with 19 MSR for which the SRR was noted it happened at V 22 and 84 (specimens PSGV 600 & PSGV 662; see David et al . 2004). Besides the differences in the suborbital stripe in males (concave vs. straight) and the lower number of midbody scale rows (19 vs. 21, exceptionally 19), Trimeresurus kuiburi sp. nov. differs from T. venustus by the absence (vs. presence) in both sexes of red dots on the lateral sides of the ventrals, the presence of white vertebral dots every 5 or 6 in males (vs. absence), a shorter tail in females ( 0.133 –0.135 vs. 0.137 –0.148 ), and the lower number of ventrals in males (164–166 vs. 166–181) (see Table 4 ). While the internasals are always in contact in Trimeresurus kuiburi sp. nov. , they are in contact in only 45% of cases in T. venustus ( David et al . 2004b ) . Trimeresurus kuiburi sp. nov. differs from T. kanburiensis by its smaller maximal SVL (451 vs. 582 mm ), internasals always in contact (vs. always separated), generally wider supraocular, higher IOS (9–11 vs. 7–9), lower number of ventrals in males (164–166 vs. 170–178), more subcaudals in males (63–65 vs. 59), more subcaudals in females (51–53 vs. 41–51), distinct dorsal color (red/purple bands on bottle green background vs. dark olive-brown bands on grayish-olive background), concave (vs. straight) suborbital stripe in males, and pale green vs. creamy white belly (see Table 4 ). White vertebral dots in males are more spaced in Trimeresurus kuiburi sp. nov. than in T. kanburiensis (5 or 6 vs. 3–5 scales apart). Geographically, Trimeresurus kuiburi sp. nov. is well separated from both T. kanburiensis and T. venustus . Trimeresurus kanburiensis is restricted to the area of Sai Yok in Kanchanaburi Province , a part of the Tenasserim Range showing a high endemism in squamates ( Sumontha et al . 2017b ), located about 300 km N-NW of the typelocality of T. kuiburi sp. nov . Trimeresurus venustus is separated from T. kuiburi sp. nov. by a gap of at least 180 km (population of Chumphon Province , whose status is not yet established, but similar to T. venustus in pattern; see Figures 9A & 9B ) or at least 350 km (other venustus -like populations). The analysis of cytochrome b revealed that mean interspecific p -distances between Trimeresurus kuiburi sp. nov. and related Trimeresurus species ranged from 4.57 % to 18.10 % , with the minimum of 4.57 % ± 0.91 % being to T. macrops and the maximum of 18.10 % ± 1.68 % being to P . mucrosquamatus ( Table 5 ). Moreover, 16S rRNA gene was analyzed and showed the interspecific p -distances between T. kuiburi sp. nov. and related Trimeresurus species ranged from 1.23 % to 8.15 % , with the minimum of 1.23 % ± 0.54 % being to T. macrops and the maximum of 8.15 % ± 1.34 % being to T. wagleri ( Table 6 ). Bayesian phylogenetic inference yielded a well - supported sister relationship between T. kuiburi sp. nov. and T. macrops . These two species are nested within the Trimeresurus clade ( Figure 14 ). Therefore, the molecular results concur with the assignment of our specimens to a new species of Trimeresurus s.s. 0.07