 |
| Acanthosaura meridiona Trivalairat, Sumontha, Kunya & Chiangkul, 2021 |
Abstract
A new short – horned lizard species of the genus Acanthosaura from southern Thailand, is described herein. The species was previously recognised as Acanthosaura crucigera and has been reported to present a wide distribution across mainland south-east Asia. The combination of modern morphological studies of Acanthosaura meridiona sp. nov. allows its separation from closely related species A. crucigera, on the basis of presenting more nuchal scales, more scales between diastema, more scales bordering rostral scales and more midline ventral scales. Mitochondrial DNA analysis also indicated a sister relationship between A. meridiona sp. nov. and A. crucigera with a 100 % probability according to Bayesian and maximum – likelihood analyses. The pairwise distance between A. meridiona sp. nov. and A. crucigera ranges from 9.9 – 11.1 %, while the distance between A. meridiona populations ranges from 0 – 0.9 %. This new discovery contributes to the redescription of the distribution of A. crucigera under Kra Isthmus and its replacement by A. meridiona sp. nov.
Keywords: crucigera complex, tropical rainforest, Thai – Malay Peninsula, ND2, taxonomy
 |
| Colour pattern variation within Acanthosaura meridiona sp. nov. (A – B) Adult female from Wang Nam Rab Resort Na Yong District, Trang Province. (C – D) Adult male from Wang Hip Dam, Thung Song District, Nakhon Si Tammarat Province. (E) Sub adult male from Wang Hip Dam, Thung Song District, Nakhon Si Tammarat Province. (F) Juvenile from Wang Hip Dam, Thung Song District, Nakhon Si Tammarat Province. |
Acanthosaura meridiona sp. nov.
Diagnosis: A medium – sized species (maximum SVL 115.1 mm for males and 118.1 mm for females) with a single short conical spine above the posterior margin of the eye; small spine on the occiput between the tympanum and the nuchal crest; tympanum scaled, large, roundish; moderately developed gular pouch; small scales intermixed with medium keeled scales on the flanks with a random distribution; nuchal crest with slightly equal rows of 8 – 10 tiny semi – conical spines; large diastema of 10 – 16 scales between the nuchal and vertebral crests; vertebral crest composed of small equally sized saw – like scales beginning in the shoulder region and decreasing in size until the base of the tail; tail 1.07 – 1.61 of SVL; black collar and black eye patch present, extending posteriorly to reach the nuchal crest. Description of the holotype: Adult male. SVL 109 mm; TL 176 mm, tail complete; HL 20.8 mm; head is one – fifth the length of the body (HL/SVL 0.19), narrow (HW/SVL 0.15), moderately tall (HD/HL 0.60), triangular in dorsal and lateral views; snout moderately long (SL/HL 0.45); rostrum moderately wide (RW/RH 2.44), steeply sloping anteriorly; canthus rostralis prominent, forming a large projecting shelf extending above the eye, composed of 14 large scales; ....
Natural history: This species usually lives near streams, waterfalls or moist areas with rocks and logs and in areas covered with high trees shading evergreen rainforests (Fig. 6). It is active during the day on various substrates such as the ground, logs, rocks, ferns of approximately 0.5 m in height, or trees 1 – 2 m above the ground. It sleeps at night approximately 1 – 2 m above the forest floor, in a log holes or under rocks on the ground. When awakened by approach or provocation, the lizards quickly climb upward, while others may drop to the ground and seek refuge under rocks or hollow logs. Our observations showed that some individuals had eaten earthworms on the ground.
Distribution. Acanthosaura meridiona sp. nov. occurs in southern Thailand according to personal field observations, including records in Na Yong District, Trang Province; Khao Bantad Wildlife Sanctuary, Trang – Phattalung Province; Krabi Province; Wang Hip River, Thung Song District, Nakhon Si Tammarat Province; Ton Lat Waterfall, Nathavee District, Songkhla Province. In addition, specimens were collected from Natural History Museum, National Science Museum, Technopolis, Pathum Thani Province at the following locations: Khanom Waterfall, Lan Saka District, Nakhon Si Tammarat Province; Tak Ta Khan, Ban Ta Khun District, Surat Thani Province; and Thale Ban National Park, Khuan Don District, Satun Province (Fig. 7).
Etymology: The specific name meridiona comes from the Latin word meridionalis, meaning southern. It is a reference to the distribution of the species in the southern region of Thailand.
We suggested the following common names: กิ้งก่าเขาหนามสั้นใต้ - kingka khaow naam sunn tai (Thai), southern short- horned lizard (English), süd-kurzhorn nackenstachler (German), and Acanthosaurus à cornes courtes du sud (French).
Poramad Trivalairat, Montri Sumontha, Kirati Kunya and Krittiya Chiangkul. 2021. Acanthosaura meridiona sp. nov. (Squamata: Agamidae), A New Short-horned Lizard from southern Thailand. Herpetological Journal. 32(1); 34-50. DOI: 10.33256/32.1.3450
