Calamaria thanhi, Ziegler, Thomas & Quyet, Le Khac, 2005

Ziegler, Thomas & Quyet, Le Khac, 2005, A new species of reed snake, Calamaria (Squamata: Colubridae), from the Central Truong Son (Annamite mountain range), Vietnam, Zootaxa 1042, pp. 27-38 : 29-35

Calamaria thanhi sp. n.

Figures 1–6 .

Holotype.— An adult female ( ZFMK 82920), adjacent to Phong Nha ­ Ke Bang National Park, Dan Hoa Commune, Minh Hoa District, Quang Binh Province, Vietnam, collected on 16 June 2003 by local people in a limestone cave of primary forest; for injuries prior to collection see Figures 1–6 .

Diagnosis.— Calamaria thanhi sp. n. can be distinguished from all congeners on the basis of the following combination of characters: 1) rostral wider than high, portion visible from above longer than prefrontal suture; prefrontal shorter than frontal, touching first two supralabials; 2) single nasal; 3) frontal hexagonal, more than 2.5 times maximum width of supraocular, and about two­thirds length of parietal; 4) paraparietal surrounded by six shields and scales; 5) eye diameter larger than eye­mouth distance; 6) preocular absent; 7) absent loreals and anterior temporals; 8) four supralabials, second and third entering orbit; fourth supralabial longest and in broad contact with parietal, third ¾ of second, first slightly shorter than third; 9) modified maxillary teeth; 10) five infralabials, three touching anterior chin shield; 11) mental not touching anterior chin shields; only first pair of chin shields meeting in midline; 12) three gular scales in midline between posterior chin shields and first ventral; 13) 198 ventrals; 21 divided subcaudal scales; 14) single anal plate; 15) smooth dorsals; dorsal scale row reduction on tail to five opposite last subcaudal anterior to terminal scute; 16) large size (total length up to 455 mm); tail moderately long, tapering gradually to a point; 17) dark bluish greyish dorsum, iridescent; anterior body with four pale zigzag bands; yellowish markings on dorsum of tail base and tail tip; 18) ventral side of body immaculate beige yellowish; underside of head greyish brownish; beige yellowish tail base with small dark flecks and dark outermost corners of subcaudals.

Description of holotype.— Rostral wider (2.6 mm) than high (1.8 mm), portion visible from above longer (1.7 mm) than prefrontal suture (1.3 mm). Prefrontal shorter (2.7 mm) than frontal (3.2 mm), touching first two supralabials. Frontal hexagonal, more than 2.5 times (2.6 mm) maximum width of supraocular (1.0 mm), length about two­thirds that of the parietal (4.7 mm). Parietal about 1.7 times length of prefrontal. Paraparietal surrounded by six shields and scales. Nasal smaller than postocular. No preocular. Postocular higher than wide, not as high (0.9 mm) as eye diameter (1.4 mm). Eye diameter larger than eye­mouth distance (1.0 mm). Distance from anterior corner of eye to centre of nostril 2.4 mm, and from anterior corner of eye to tip of snout 3.8 mm. Four supralabials, second and third entering orbit, fourth longest, third ¾ of second, first slightly shorter than third and about half as long as second. Mental semicircular to triangular, not touching anterior chin shields. Five infralabials, three touching anterior chin shield. First pair of chin shields meeting in midline, second pair diverging and only touching anterior. Three gulars in midline between posterior chin shields and first ventral. 198 ventral scales, and 21 divided subcaudals. A single anal scale. Thirteen smooth scales across the midbody.

The number of dorsal scale rows is reduced to six rows on tail opposite 8th subcaudal posterior to cloaca (reduction to five rows only opposite last subcaudal anterior to terminal scute).

Snout­vent length 424 mm, tail length 31 mm. Body thickness about 7 to 8 mm, tail root 5.5 mm thick. Tail moderately long, relatively thin, tapering gradually to a point. Ratio of tail to total length (455 mm) is 0.068. Vermiform habitus, head indistinct from neck. Modified (most probably nine) maxillary teeth.

Colour preserved in ethanol dark bluish to greyish above, iridescent. Parietals and subsequent scales with indistinct light beige to yellowish markings. Lower parts of supralabials yellowish, most distinct below and somewhat behind the eyes. Dorsal scales posterior in part with more or less light markings, especially on the sides of the anterior body half. Outermost dorsal scale rows light yellowish beige below. Four beige to yellowish dorsal bands are well discernible in the anterior body half: each band is half a scale to two scales broad, somewhat zigzag shaped and turns into the yellowish beige coloration of the venter. The first yellowish dorsal band is located about 1 cm behind the head, the others follow each with distances of about 3.5 cm. Small yellowish markings can be found on the dorsum of the tail base as well as on the dorsal tail tip: whereas the anterior light dorsal area, situated about half a centimetre behind the anal scale, is recognizable as rudiment of a thin zigzag shaped band, comprising five scale rows, the yellow fleck on the tail’s end covers only the hind part of a single scale bordering the tail tip. The ventral side of the body is immaculate yellowish to beige. Similar to the body venter the tail base is yellowish beige except for some small dark flecks and the dark outermost corners of the subcaudals. The underside of the head appears greyish to brownish.

Etymology.— We dedicate this new species to our friend and colleague Vu Ngoc Thanh ( Vietnam National University, Hanoi, University of Science, Faculty of Biology, Department of Vertebrate Zoology, Zoological Museum) in recognition of his valuable support during numerous biodiversity excursions in Vietnam.

As common names we suggest Thanh’s reed snake (English), Ran mai gam Thanh (Vietnamese), Calamaire de Thanh (French), and Thanhs Zwergschlange ( German).

Comparisons.— Calamaria thanhi sp. n. differs according to Inger & Marx (1965) and Darevsky & Orlov (1992) from the Vietnamese species as follows:

C. buchi is blackish above, each dorsal scale with small light spots; in addition, C. buchi has a higher count of ventral scales (221–236 vs. 198 in C. thanhi sp. n.), fewer subcaudal scales (13–14 vs. 21), preocular present, rostral higher than wide (vs. rostral wider than high), its mental touching the anterior chin shields (which is not the case in C. thanhi sp. n.), only five (vs. six) scales touch the paraparietal, dorsal scale reduction to four rows on tail opposite the third to fourth subcaudal anterior to terminal scute, and a ratio of tail to total length of 0.039 to 0.041 (vs. 0.068) in females.

C. pavimentata usually has narrow, dark, longitudinal stripes, a solid black collar immediately behind the neck, ventrals with dark lateral tips, a slightly smaller first supralabial than the second (vs. a first supralabial that is about half as long as second in C. thanhi sp. n.), the second pair of chin shields meeting in midline (which is not the case in C. thanhi sp. n., where the second pair diverges and only touches anteriorly), a rostral that is as broad as high (or slightly higher vs. a rostral that is wider than high), dorsal scale row reduction usually to four (vs. five) on tail, a rostral portion visible from above only onehalf to equal entire length of prefrontal suture (vs. a rostral portion visible from above longer than prefrontal suture in C. thanhi sp. n.), and a preocular present.

C. septentrionalis has dorsal scales with many small light dots forming a network, lower counts of ventral and subcaudal scales in females (168–188 vs. 198 and 6–11 vs. 21), rostral portion visible from above less than one­third length of prefrontal suture (vs. a rostral portion visible from above longer than prefrontal suture in C. thanhi sp. n.), preocular present, the tail being as thick as body, not tapering, with a broadly rounded tip (vs. a relatively thin tail in C. thanhi sp. n. that is tapering gradually to a point), and a ratio of tail to total length of 0.026 to 0.043 (vs. 0.068) in females.

C. lovii ingermarxorum has an immaculate grey­bluish dorsum with light spots on each side of the neck covering four scales, uniformly dark grey ventrals with light posterior edges, prefrontals being longer than frontal (vs. prefrontals shorter than frontal in C. thanhi sp. n.), rostral portion visible from above more than half length of prefrontal suture (vs. a rostral portion visible from above longer than prefrontal suture), its mental touching the anterior chin shields, dorsal scale reduction to four rows on tail opposite first to fifth subcaudal anterior to terminal scute, and a short, blunt tail that is not tapering (vs. a relatively thin tail that is tapering gradually to a point).

Our new Calamaria species can be distinguished from the other subspecies of C. lovii , that do not occur in Vietnam, according to Inger & Marx (1965) e.g. by its quite large total length (455 mm vs. 316 mm in C. l. lovii Boulenger, 315 mm in C. l. wermuthi Inger & Marx, and 269 mm in C. l. gimletti Boulenger), the ventral and subcaudal counts (198 and 21 vs. 218–254 and 11–18 in C. l. lovii , 256 and 11 in C. l. wermuthi, and 215–249 and 10– 12 in C. l. gimletti ), by its eye diameter being larger than the eye­mouth distance and by a differing coloration and pattern; in addition, contrary to the situation in C. thanhi sp. n., in C. l. lovii and C. l. wermuthi the mental touches the anterior chin shields and in C. l. gimletti the rostral portion visible from above is distinctly smaller than the prefrontal suture (vs. a rostral portion visible from above being longer than prefrontal suture in C. thanhi sp. n.).

Calamaria thanhi sp. n. differs from the Chinese species C. yunnanensis Chernov , that was judged as doubtful form by Inger & Marx (1965), but listed as valid by Yang & Inger (1986) or Zhao & Adler (1993), in lacking narrow, dark, elongated stripes along the body, dark edges on the ventrals, and in having a higher ventral count (198 vs. 173) as well as in a lower tail ratio (0.068 vs. 0.082).

From the four Calamaria species, that reach Malay Peninsula ( C. albiventer Gray , C. ingeri Grismer, Kaiser & Yaakob , C. schlegeli Duméril & Bibron ) and Thailand ( C. lumbricoidea Boie ) in the north, C. thanhi sp. n. is distinguishable in lacking five supralabials, of which the third and fourth entering the orbit (namely four supralabials with second and third entering orbit in C. thanhi sp. n.), and in lacking a preocular (present in C. albiventer , C. ingeri and C. lumbricoidea ), in lacking a mental that touches the anterior chin shields (as is present in C. albiventer and C. lumbricoidea ), in having a higher ventral count in females (198 vs. 136­180 in C. schlegeli and vs. 147­162 in C. albiventer ), by having a paraparietal that is surrounded by six and not only by four or five scales or shields as in C. lumbricoidea , as well as in pattern ( C. albiventer : body with four narrow light stripes, C. lumbricoidea : belly with black crossbars, C. schlegeli : distinctly bicolored).

Most of the remaining, geographically quite distant Calamaria species from Sumatra, Borneo, Java, the Philippines, Sulawesi and the Moluccas can be distinguished from C. thanhi sp. n. not only by coloration and pattern but also by the presence of the (due to its limited intraspecific variation) stable character of five supralabials (four in C. thanhi sp. n.), of which, in addition, the third and fourth (and not the second and third as in C. thanhi sp. n.) enter the orbit ( C. abstrusa Inger & Marx , C. acutirostris Boulenger , C. alidae Boulenger , C. apraeocularis Smith , C. bicolor Duméril & Bibron , C. bitorques Peters , C. boesemani Inger & Marx , C. brongersmai Inger & Marx , C. ceramensis de Rooij, C. crassa Lidth de Jeude, C. curta Boulenger , C. doederleini Gough , C. eiselti Inger & Marx , C. everetti Boulenger , C. forcarti Inger & Marx , C. gervaisi Duméril & Bibron , C. grabowskyi Fischer , C. griswoldi Loveridge , C. hilleniusi Inger & Marx , C. joloensis Taylor , C. lateralis Mocquard , C. lautensis de Rooij, C. leucogaster Bleeker , C. lumholtzi Andersson , C. margaritophora Bleeker , C. mecheli Schenkel , C. modesta Duméril & Bibron , C. muelleri Boulenger , C. nuchalis Boulenger , C. palavanensis Inger & Marx , C. prakkei Lidth de Jeude, C. rebentischi Bleeker , C. suluensis Taylor , C. sumatrana Edeling , C. ulmeri Sackett , and C. virgulata Boie ). Of the remaining species, C. battersbyi Inger & Marx , C. borneensis Bleeker , C. linnaei Boie , and C. melanota Jan possess a preocular, C. schmidti Marx & Inger bears unmodified maxillary teeth, C. gracillima (Günther) has the supraocular fused with the postocular, and C. javanica Boulenger has, besides distinctly lower subcaudal counts in females (10–12 vs. 21), four gulars (vs. three gulars in C. thanhi sp. n.) in midline between posterior chin shields and first ventral, which clearly distinguish all of them from C. thanhi sp. n.

Distribution and Natural History.— Calamaria thanhi sp. n. is only known from the type locality. Records for Laos are to be expected in the future, due to the close proximity of the type locality to the Laotian border.

The snake was found heavily injured on the ground of a large limestone cave under a mist net. Further records of that species must confirm, whether C. thanhi sp. n. is adapted to primary limestone forest caves. The adult female, which was collected during the dry season, contained at least seven large eggs besides smaller ova in the ovaries; folded oviducts indicated, that eggs had already been laid. Concerning the larger eggs, mean egg length measured 10.7 +/­ 1.5 mm (min. 8.0, max. 12.2 mm), mean egg width was 3.4 +/­ 0.9 mm (min. 2.3, max. 4.5 mm).

Figures

FIGURE 1. Dorsal view of the ethanol­preserved holotype of Calamaria thanhi sp. n. (ZFMK 82920).

FIGURE 2. Ventral view of the ethanol­preserved holotype of Calamaria thanhi sp. n. (ZFMK 82920).

FIGURE 3. Oblique view of the head and neck region of the ethanol­preserved holotype of Calamaria thanhi sp. n. (ZFMK 82920).

FIGURE 4. Lateral view of the head of the ethanol­preserved holotype of Calamaria thanhi sp. n. (ZFMK 82920).

FIGURE 5. Ventral view of the head of the ethanol­preserved holotype of Calamaria thanhi sp. n. (ZFMK 82920).

FIGURE 6. Dorsal view of the tail of the ethanol­preserved holotype of Calamaria thanhi sp. n. (ZFMK 82920). Photos by Thomas Ziegler.