Thursday, June 30, 2022

[Herpetology • 2022] Lycodon ankardaya & L. truongi • Two New Syntopic Species of Wolf Snakes Genus Lycodon (H. Boie in Fitzinger, 1826) (Squamata: Colubridae) from An imperiled Ecosystem in the Song Giang River Valley of southern Vietnam


Lycodon ankardaya
Lycodon truongi  

Nguyen, Duong, Wood & Grismer, 2022. 

Abstract
An integrative taxonomic analysis of species in the colubrid genus Lycodon Fitzinger, 1826 recovered two new syntopic species of the L. rufozonatus complex from the imperiled Song Giang River valley in Khan Hoa Province, of Southern Vietnam. Although L. truongi sp. nov. and L. anakradaya sp. nov. are syntopic, they are not particularly closely related and can be differentiated from each other and all other species in the L. rufozonatus complex on the basis of meristics, morphometrics, color pattern, and uncorrected pairwise genetic distance based on the mitochondrial gene cytochrome b. The discovery of these two new range-restricted species and a previously described range-restricted gekkonid in the genus Cyrtodactylus Gray, 1828 from the same valley, underscores the necessity of continued field work in the Song Giang River valley so as to catalog the unrealized herpetological diversity in this area and establish research-based conservation programs.

Keywords: Colubrid, conservation, integrative taxonomy, Khanh Hoa Province, Southeast Asia

Holotype of Lycodon truongi sp. nov. SIEZC 20249
 from the Song Giang River Valley Khanh Trung Commune, Khanh Vinh District, Khanh Hoa Province, Vietnam.
A Dorsal view of head. B Gular region. C Lateral view of head. D Dorsal view of body. E Ventral view of body.
Photographs by Anh The Nguyen.

Lycodon truongi sp. nov. 

Suggested common name: Truong’s wolf snake 
— Rắn khuyết Trường.

Diagnosis: Lycodon truongi sp. nov. is separated from all other species of the L. rufozonatus complex by having the combination of a maximum SVL length of 700 mm; tail length 195 mm; 17–17–15 dorsal scale rows; 14 maxillary teeth; eight supralabials with the third–fifth contacting the eye; nine infralabials; one preocular; two postoculars; an elongate loreal not contacting the eye; two anterior temporals; two posterior temporals; 200 ventral scales; 91 paired subcaudal scales; a divided precloacal plate; 15 keeled vertebral scale rows from midbody to vent; uniform dark-brown to black adult head pattern; no wide light-colored nuchal-occipital collar in the adult; black dorsal ground color; 19 narrow white body bands; 13 white caudal bands; white dorsal bands on ventrolateral section of body as opposed to a reticulated pattern; anterior one-half of venter white, and posterior of venter bearing white and broken black bands. These characters are scored across all species of the L. rufozonatus complex in Table 2.

Etymology: The specific epithet “truongi” is a patronym honoring Professor Dr. Quang Truong Nguyen for his long-standing extensive contributions to the herpetology of Vietnam and his broad international collaborations.


A. Holotype of Lycodon ankardaya sp. nov. SIEZC 20247.
B Holotype of Lycodon truongi sp. nov. SIEZC 20248.
C Paratype of Lycodon ankardaya sp. nov. SIEZC 20248.
Photographs by Anh The Nguyen.

Lycodon anakradaya sp. nov. 

Suggested common name: Rhade wolf snake 
– Rắn khuyết Ê đê.

Diagnosis: Lycodon anakradaya sp. nov. is separated from all other species in the L. rufozonatus complex by having the combination of a maximum SVL length of 790 mm; TaL 190 mm; 17 or 18–17–15 dorsal scale rows; 12 maxillary teeth; eight supralabials with the 3rd–5th contacting the eye; nine or 10 infralabials; one preocular; two postoculars; an elongate loreal not contacting the eye; two anterior temporals; three posterior temporals; 223–232 ventral scales; 87 paired subcaudal scales; a divided precloacal plate; five keeled vertebral scale rows from midbody to vent; uniform dark-brown to black adult head pattern; no wide light-colored nuchal-occipital collar; dark-brown/black dorsal ground color; 12 wide, orangish body bands; 5–7 orangish caudal bands; orangish dorsal bands on ventrolateral section of body as opposed to a reticulated pattern; and anterior one-half of venter orangish grading into a dark-brown posteriorly. These characters are scored across all species of the L. rufozonatus complex in Table 2.

Etymology: The specific epithet “anakradaya” is given in a reference to the Ede people (“Anak Radaya” in Ede language), an Austronesian ethnic group living in the upland forested areas of southern Vietnam including those that surround the Song Giang River valley.


Anh The Nguyen, Tang Van Duong, Perry L. Wood Jr. and L. Lee Grismer. 2022. Two New Syntopic Species of Wolf Snakes (genus Lycodon H. Boie in Fitzinger, 1826) from an imperiled Eecosystem in the Song Giang River Valley of southern Vietnam (Squamata: Colubridae). Vertebrate Zoology. 72: 371-384. DOI: 10.3897/vz.72.e82201