Parafimbrios lao, Teynié, Alexandre, David, Patrick, Lottier, Anne, Le, Minh Duc, Vidal, Nicolas & Nguyen, Truong Quang, 2015

Teynié, Alexandre, David, Patrick, Lottier, Anne, Le, Minh Duc, Vidal, Nicolas & Nguyen, Truong Quang, 2015, A new genus and species of xenodermatid snake (Squamata: Caenophidia: Xenodermatidae) from northern Lao People’s Democratic Republic, Zootaxa 3926 (4), pp. 523-540 : 527-536

publication ID	https://doi.org/ 10.11646/zootaxa.3926.4.4
publication LSID	lsid:zoobank.org:pub:6CCC3C5B-0DF1-4677-B9E9-BD49941921D4
DOI	https://doi.org/10.5281/zenodo.5687316
persistent identifier	https://treatment.plazi.org/id/038BC44B-FFFC-FFB0-FF44-46F6FB07FE38
treatment provided by	Plazi
scientific name	Parafimbrios lao
status	sp. nov.

Treatment

Parafimbrios lao spec. nov.

( Figs. 2–4 View FIGURE 2 View FIGURE 3 View FIGURE 4 ; 5A, B; 6B)

Holotype. MNHN 2013.1002, a young adult male, from the vicinity of Muang Ngoi (20°42.005'N, 102°41.730'E; datum WGS84), Ngoi District, Louangphabang Province, Laos , at an elevation of ca. 360 m a.s.l.; collected by Alexandre Teynié and Anne Lottier on 25 September 2012.

Additional material. A second specimen was found, examined and photographed ( Fig. 4 View FIGURE 4 ) but not collected, in the vicinity of Vieng Xai, or Viengxay (20°24.417'N, 104°13.433'E), Vieng Xai District, Houaphan Province, Laos , at an elevation of ca. 890 m a.s.l., by Alexandre Teynié and Anne Lottier on 11 May 2013.

This specimen was released after obtaining morphological characters and photographing.

Diagnosis. A species of the genus Parafimbrios gen. nov., defined by a combination of generic characters listed above plus (1) dorsal scale rows 27–29 – 25–27 – 23–25, distinctly keeled, small, cycloid, progressively larger on the top of the body than on the sides; (2) scales of the first DSR distinctly enlarged, also two per ventral, first smallest, last largest; (3) ventrals 177–189, large, laterally rounded; (4) subcaudals 55–56, undivided; (5) 1st–4th or 1st–5th supralabials, mental, and 2nd–4th infralabials with raised and everted edges; (6) suture between the internasals 0.7 times as long as suture between the prefrontals; (7) 1 / 1 (upper) preocular, 1 / 1 supraocular, 2 / 2 postoculars, and 1 / 1 subocular; (8) 1 / 1 loreal, large; (9) nuchal scales 3, one in central and one enlarged on each side; (10) dorsum dark purplish-grey, slightly paler on the sides; and (11) neck with a pale creamish-grey collar, more or less pronounced with age, reaching downwards the pale grey colour of the venter.

Etymology. The specific epithet, lao , refers both to the official name of Laos , the Lao People’s Democratic Republic in which the species was discovered, and to the Lao , the main people group inhabiting Laos .

Description of holotype. Body elongate, slightly laterally compressed; head short (4.1% of SVL), ovoid, not distinct from the thick neck, dorsally covered with large shields; snout average, approximately 3.1 times as long as eye diameter, distinctly extending beyond lower jaw, rounded in profile and from above; a large, oval nostril, piercing in the anterior part of a large, concave nasal; eye small, its diameter 0.7 times of the distance between eye and lip, with a vertically elliptic pupil; tail average, relatively thick, tapering progressively.

Measurements. SVL 236 mm; TaL 49 mm; TL 285 mm; ratio TaL/TL 0.172; HL 9.75 mm; SnL 2.75 mm.

Dentition. Maxillary teeth: right maxilla with 27 small, curved, subequal teeth, progressively slightly enlarged posteriorly.

Body scalation. DSR 27-25-23, small, cycloid or subrectangular, not elongate, barely imbricate and distinctly keeled with a narrow keel, outermost rows formed by small and enlarged scales alternately; each ventral topped by two dorsal scales above, anterior small, posterior enlarged and surrounding the posterior lateral portion of the corresponding ventral.

The dorsal scalation of this species is quite peculiar. On the 1st DSR, the anterior small scale is in contact with its corresponding ventral on the anterior part of the body, narrowly separated by an area of skin posteriorly; the posterior enlarged scale is always in contact with the posterior lateral portion of the corresponding ventral. Scales on 2nd–7th DSR small, slightly enlarged on 8th–9th DSR, moderately enlarged on 10th–11th DSR, and distinctly enlarged on 12th DSR; scales of vertebral row hexagonal.

The dorsal scale row reductions are as follows:

5+6 → 5 (VEN 18) (left) 6+7 → 6 (VEN 114) (left)

27 ————————— 25 ————————— 23

5+6 → 5 (VEN 25) (right) 6+7 → 6 (VEN 115) (right)

VEN 177 (+ 2 preventrals), laterally rounded; SC 56, undivided; cloacal plate entire, large; terminal caudal scale pointing.

Head scalation. Upper head scalation complement complete, comprising 2 internasals, 2 prefrontals, 2 supraoculars, 1 frontal, and 2 parietals. Rostral large, wider than high, not visible from above due to the presence of a ridge of skin between rostral and internasals; nasal 1 / 1, large, elongate, pentagonal, 1.3 times as long as high, entire, most of forward part of scale area being occupied by the nostril; internasals subrectangular, narrow, much wider than long, separated from each other by a short suture, 0.7 times as long as the suture between prefrontals, internasals 0.6 times as long as prefrontal; prefrontals large, pentagonal, much wider than long, 0.75 times as long as frontal, separated from each other by a suture 0.65 times as long as frontal; supraoculars small, slightly beanshaped, approximately 1.3 times as long as broad, 0.25 times as wide as frontal and 0.5 times as wide as internasals; frontal hexagonal, abruptly truncated anteriorly with its apex pointing backwards, large and especially wide, rather squat, 1.5 times as wide as long; parietals strongly enlarged, roughly heptagonal with a jagged posterior edge, longer than wide, extending on about 47% of head length, about 1.6 times longer than frontal, altogether forming a “bat-like” shape; nuchal scales 3, one in central, coarsely rounded, inserted between the posterior inner limits of parietals, and much larger one on each side, larger than upper temporal, edging the whole of the posterior outer margin of each parietal; loreal 1 / 1, large, subrectangular, covering nearly the whole of the side of the snout between nasal and eye, entering the lower half of orbit, much longer and higher than anterior supralabials, 1.2 times longer than high; SL 8 / 8, anterior and posterior edges of 1st–4th strongly everted and raised, much less so on the anterior edge of 5th, 8th largest, narrow and distinctly elongate; 1st–3rd SL in contact with nasal, 3rd–5th in contact with loreal, 5th–6th and a part of 7th in contact with subocular, 7th bordering the “postsubocular” (the scale inserted between subocular), lower anterior temporal and posterior supralabials, 8th in contact with “postsubocular” and lower temporal; preocular 1 / 1, small, higher than long, entering the upper anterior part of orbit, in contact with loreal below and prefrontal above, not reaching the frontal; subocular 1 / 1, large, long and tall, just below the eye; postoculars 2 / 2, relatively large, higher one slightly enlarged; postsubocular 1 / 1, relatively large, inserted behind subocular and lower postocular; temporals 2 + 2 on each side, upper anterior one large and elongate, lower anterior one smaller, posterior ones larger, upper posterior one in broad contact with the lateral nuchal scale (which cannot be qualified of temporal as it is high on the side of the head and barely on the temporal regions); IL 8 / 8, 1st very narrow, in contact with each other behind mental, 1st–4th in contact with the sole pair of chin shields, 1st–4th with strongly raised and everted anterior edges; mental small, with a strong transversal ridge; chin shields in contact with each other in anterior half, diverging and separated by a scale posteriorly.

Hemipenis. In situ, the hemipenis is long, reaching the level of 12th SC, forked at level of 9th SC; half proximal part of the organ and area on the side of the sulcus close to the bifurcation smooth; distal half of the organ strongly spinose, covering broad spines; sulcus spermaticus very prominent.

Colour and pattern. Body uniformly dark purplish-grey or purplish / brownish-grey, slightly iridescent and somewhat paler on the lower sides, more dark grey than brown; scales of the first DSR edged in cream posteriorly; a broad, white (in life) or pale creamish-grey (in preservative) nuchal collar, extending from the occiput and temporal region to the anterior part of the body up to the level of the 10th VEN, in length of 11 vertebral scales on the top of the body, narrowing progressively, downwards with an irregular, wavy posterior limit, narrower at midheight of the side, in width of 9 dorsal scales, widening progressively downwards and connect with the pale colour of the venter; tail in shades of dark purplish-grey as the body.

Head dark purplish-brown, slightly darker than the body, more purplish brown anteriorly; side of snout slightly paler; supralabials paler greyish-brown anteriorly, progressively heavily speckled with whitish-brown; 8th supralabial and lower posterior temporal, turning to pale creamish-grey as the nuchal collar; chin dark purplishbrown, turning quickly to dark then medium grey; throat uniformly pale grey, darker on posterior infralabials.

Venter uniformly pale grey, with, on the anterior part of the body, the outer quarter of each ventral dark grey as the lower part of body, progressively reduced to a dark grey blotch on the posterior margin of the tip of each ventral; ventral surface of the tail dark grey, distinctly darker than the venter.

Variation. The second specimen (male; Vieng Xai, Houaphan Province; Fig. 4 View FIGURE 4 ) has the following main characters:

Measurements (approximate). SVL 298 mm; TaL 55 mm; TL 353 mm; ratio TaL/TL 0.156.

Body scalation. DSR 27-25-23, similar to that of the holotype, especially the two consecutive rows of dorsal scales above each ventral.

VEN 189 (+ 1 preventral), laterally rounded; SC 55, all undivided; cloacal plate entire.

Head scalation. Upper head scalation complement complete, comprising 2 internasals, 2 prefrontals, 2 supraoculars, 1 frontal, and 2 parietals; SL 7 / 7, anterior and posterior edges of 1st–3rd strongly everted and raised, much less developed on the anterior edge of 4th, 7th largest, narrow and distinctly elongate; 1st–3rd SL in contact with nasal, 4th–5th in contact with loreal, 6th in contact with subocular, 6th–7th bordering the “postsubocular”, 7th in contact with lower temporal; preocular 1 / 1, small; subocular 1 / 1, large; postoculars 2 / 2, relatively large; temporals 2 + 2 / 2 + 1; IL 7 / 7, 1st–4th in contact with the sole pair of chin shields, 1st–3rd with strongly raised and everted anterior edges; other characters of head scalation agree with those of the holotype.

Colour and pattern. Body uniformly dark purplish-grey or dark purplish-brown, depending on the angle of the light source, barely paler on the lower sides, distinctly iridescent; scales of first dorsal scale rows narrowly edged with pinkish-cream on their hinder margins; only the lower half of the neck pinkish-white as a broad triangle, the apex of which about at mid-height of the side of the neck, the base extending from the corner of the mouth to the level of the 10th VEN; upper part of the neck coloured as the body; tail in shades of dark purplish-grey or dark purplish-brown as the body.

Head dark purplish-brown, behind slightly darker than the body, paler and more purplish brown anteriorly; side of snout slightly paler; supralabials brown, paler than upper head surface anteriorly, progressively creamishbrown; 7th supralabial and lower posterior temporal creamish-brown, darker than the nuchal collar; chin dark purplish-brown, turning quickly to medium grey; throat uniformly pale pinkish-grey, darker on hinder infralabials.

Venter uniformly pinkish-cream or very pale pinkish- grey, with, on the anterior part of the body, the outer quarter of each ventral dark greyish-brown, progressively reduced to a dark greyish-brown blotch on the posterior margin of the tip of each ventral; ventral surface of the tail dark grey, distinctly darker than the venter.

Comparisons. The genus Parafimbrios can be distinguished from all genera of Xenodermatidae , at the partial exception of Fimbrios , by a series of diagnostic characters at the generic level given above in the introduction to its description. The combination of (1) 2 dorsal scale rows above each ventral; (2) dorsal scale rows very small, uniform in shape; (3) supralabials and infralabials with strongly everted edges; (4) 27 maxillary teeth; and (5) 25–27 dorsal scale rows at midbody, is sufficient to distinguish this species from members of the genera Xenodermus , Stoliczkia , Achalinus , and Xylophis . Furthermore, the relatively slender body of Parafimbrios lao spec. nov. is closer to the habitus of members of the genus Achalinus than of Fimbrios but much less slender than the habitus of Xenodermus and Stoliczkia . However, Parafimbrios lao spec. nov. readily differs from all the species currently included in the genus Achalinus by its much more strongly erected ridges on labial scales, which are barely or not erected in Achalinus .

Parafimbrios lao spec. nov. shares several similarities with the two species of the genus Fimbrios currently recognized, F. klossi ( Figs. 5 View FIGURE 5 C & 6A) and F. smithi ( Fig. 5 View FIGURE 5 D).

According to Smith (1921, 1943), Campden-Main (1970), Orlov et al. (2003), Ziegler et al. (2008) and our own data, Parafimbrios lao spec. nov. differs from both species of the genus Fimbrios by (1) a more slender body, (2) fewer maxillary teeth (27 vs. at least 30), (3) only 25 or 27 DSR at midbody vs. at least 30, (4) 2 dorsal scale rows per ventral plate vs. one, (5) a shorter tail with a ratio of Tal/TL of 0.156–0.172 vs. 0.185–0.197 in males of F. klossi and 0.214 in the single known male of F. smithi , (6) and by the pale creamish-grey nuchal collar, vs. no pattern in F. klossi and only pale blotches and stripes in the neck region in F. s m i t hi. Furthermore, Parafimbrios lao spec. nov. has more ventrals than in F. klossi , (177–189 vs. 161–176 in F. klossi ) but fewer than in F. smithi (193 VEN). Bourret (1937) mentioned a specimen of F. klossi (M. 558) with 190 ventral scales, a value reported by Campden-Main (1970). This specimen was not examined but we suspect that it might belong either to F. s m i t hi or to another undescribed species. Bourret (1937) emphasized the unusually high ventral scale count of that specimen but did not mention any other difference compared with F. klossi . He counted 53 subcaudals in this specimen that, furthermore, had a bluish-grey dorsum, 315 mm total length, and a tail length / total length ratio of 0.16. All other known specimens of F. klossi have less than 180 ventrals.

Parafimbrios lao spec. nov. also differs from F. klossi in having only the first 3 or 4 infralabials with raised edges vs. first 7 infralabials in F. klossi . Lastly, Parafimbrios lao spec. nov. differs from F. s m i t h i by having (1) fewer subcaudals (55–56 vs. 72 in F. s m i t hi), (2) suture between internasals shorter than that between prefrontals (character shared with F. kl os s i) vs. distinctly longer in F. smi thi , (3) 1 subocular vs. 2, and (4) 3 posterior temporals vs. 5.

Distribution ( Fig. 7 View FIGURE 7 ). Laos . Louangphabang Province: Vicinity of Muang Ngoi Village, Muang Ngoi District and Houaphan Province: Vicinity of Vieng Xai, Vieng Xai District.

This species is currently known from its type and near the historical city of Vieng Xai or Viengxay, separated by 162 airline kilometers.

Natural history. The holotype of Parafimbrios lao was discovered in a steep, rocky evergreen forest, with some remaining trees of primary forest, surrounding a rugged karst formation ( Fig. 8 View FIGURE 8 ). The holotype was lying motionless at night (19.45) during the rainy season on a rocky outcrop among a large pile of rocks at the foot of a limestone cliff of the karst formation at an elevation of 360 m. A few dozens of meters down below, a water course, about 1 m wide and 40 cm deep, used to run in this period of the year. The collection site is located on a steep slope which is converted into cultures (bananas, chilli beans) when the slope becomes more moderate. The adjacent lowland is mainly covered with rice fields, patches of secondary forests and a few scrub and grasslands.

The second specimen was observed around the historical city of Vieng Xai, “Birth place of Lao PDR”. It was found near one of the “Former Pathet Lao Leaders Caves”, a place heavily bombed by the U.S. Air Force from 1964 to 1973 and where no large primary forest remain. This specimen was observed in the same general karstic environment as the holotype. It was lying motionless at the beginning of the rainy season on a rocky outcrop emerging near a cave entrance and an anti-rocket wall at the foot of a limestone cliff of the karst formation at an elevation of 890 m. No water course, except an artificial pool, was seen in its vicinity. The adjacent area is mainly covered with some small parcels comprising, among others, bananas, chilly beans and peanuts.

Both specimens did not display any reaction and remained perfectly motionless when they were photographed. When they were handled, they did not try to form a “ball”, a defensive posture frequent in Fimbrios klossi (our data), nor did they display any other defensive action. Nothing else is known on the biology of Parafimbrios lao . Stomachs of both specimens were seemingly empty.

In the same biotope and within 50 meters from the collection site of the holotype we found the following amphibians: Microhyla fissipes (Boulenger) , Micryletta inornata (Boulenger) , Leptobrachium smithi (Matsui, Nabhitabhata & Panha) , Xenophrys major (Boulenger) , Hoplobatrachus chinensis (Osbeck) , Ferjervarja limnocharis (Gravenhorst), and Theloderma asperum (Boulenger) . We also found several reptile species, some of them new for the province ( Teynié et al. 2014b). In the vicinity of the locality of the second specimen, we found Microhyla fissipes , Micryletta inornata , and Rhacophorus kio (Ohler & Delorme) , as well as at least seven reptile species. All species were photographed. Lastly, quite interestingly, each locality of Parafimbrios lao included in its fauna a different species of the genus Cyrtodactylus , new to the fauna of Laos ( Schneider 2014) .