Theloderma lacustrinum, Sivongxay, Niane, Davankham, Monekham, Phimmachak, Somphouthone, Phoumixay, Keochay & Stuart, Bryan L., 2016

Sivongxay, Niane, Davankham, Monekham, Phimmachak, Somphouthone, Phoumixay, Keochay & Stuart, Bryan L., 2016, A new small-sized Theloderma (Anura: Rhacophoridae) from Laos, Zootaxa 4147 (4), pp. 433-442 : 434-436

publication ID

https://doi.org/ 10.11646/zootaxa.4147.4.5

publication LSID

lsid:zoobank.org:pub:86E9C17F-F09C-49C2-BB33-4F8FFF2381A2

DOI

https://doi.org/10.5281/zenodo.5662226

persistent identifier

https://treatment.plazi.org/id/BF7387C3-490F-FFAF-FF37-7735171D7E8C

treatment provided by

Plazi

scientific name

Theloderma lacustrinum
status

sp. nov.

Theloderma lacustrinum View in CoL sp. nov.

Holotype. NCSM 84682 View Materials (field tag SP 00299), adult male ( Fig. 1 View FIGURE 1 ), Laos, Vientiane Province, Feuang District, Ban Naxang Village, bank of Nam Lik Reservoir , Houay Poungfan Stream , 18º48’59.5”N 102º08’06.1”E, 292 m elev., coll. 16 March 2015 by Niane Sivongxay, Monekham Davankham, Somphouthone Phimmachak, and Keochay Phoumixay. GoogleMaps

Paratypes. NUOL 0 0 0 43 (one juvenile), NUOL 0 0 0 44 (one male), same data as holotype GoogleMaps . NUOL 0 0 970 (one male), same data as holotype except coll. 16 December 2014 by Niane Sivongxay, Monekham Davankham, and Keochay Phoumixay GoogleMaps . NCSM 84683, NUOL 0 0 0 45 (two males), same data as holotype except Houay Kengthang Stream, 18º51’58.2”N 102º07’20.6”E, 361 m elev., coll. 17 March 2015. GoogleMaps

Etymology. The specific epithet taken from lacustrinus L., of lakes, in reference to Nam Lik Reservoir, a large, man-made reservoir formed by a hydropower dam that has inundated the vicinity of the type locality.

Diagnosis. Assigned to the genus Theloderma on the basis of molecular data ( Fig. 2 View FIGURE 2 ). A very small-sized (second smallest known) species of Theloderma having the combination of males with SVL 17.0–20.6; pearly asperities on dorsum; no vomerine teeth; disc diameter of finger III ca. 40% of tympanum diameter; uniformly gray venter; light brown dorsum with darker brown and black markings; and a uniformly bronze iris with small black reticulations.

Description of holotype. Habitus slender. Head longer than wide. Snout slightly rounded in dorsal and lateral views; nostril oval, slightly oblique, much closer to tip of snout than to eye, internarial shorter than interorbital distance; canthus rostralis indistinct, rounded, slightly constricted behind nares; lores oblique, concave; interorbital region slightly convex, interorbital distance greater than upper eyelid width; pupil diamond-shaped, horizontal; eye diameter and snout length subequal; tympanum distinct, round, 70% of eye diameter, tympanic rim elevated relative to skin of temporal region; pineal ocellus absent; vomerine teeth absent; choanae oval, at margins of roof of mouth; tongue wide, attached anteriorly, deeply notched posteriorly; supratympanic fold from posterior margin of eye to level slightly posterior to axilla.

Forelimb slender. Finger tips with slightly expanded discs having weakly visible circummarginal grooves, finger III disc width 40% tympanum diameter; fingers slender; relative finger lengths I <II <IV <III; webbing on fingers absent; subarticular tubercles conspicuous, surfaces rounded, formula 1, 1, 2, 2; two indistinct, oval, palmar tubercles in contact, subequal in size, surfaces flat; oval, thenar tubercle, surface flat; round, indistinct supernumerary tubercles.

Hindlimb slender. Toe tips with slightly expanded discs having weakly visible circummarginal grooves, diameter of discs subequal to those of fingers; toes slender; relative toe lengths I<II<III<V<IV; rudimentary web on toe I to level of center of subarticular tubercle, continuing as fringe on preaxial side of toe II to base of tip, on postaxial side of toe II to level of distal margin of subarticular tubercle, continuing as fringe on preaxial side of toe III, on postaxial side of toe III to level midway between subarticular tubercles, on preaxial side of toe IV to level of distal margin of proximal subarticular tubercle, continuing as fringe to base of disc, postaxial side of toe IV to level of proximal margin of penultimate subarticular tubercle and continuing as a fringe to base of tip, and on toe V to level of proximal margin of subarticular tubercle; subarticular tubercles conspicuous, surfaces rounded, formula 1, 1, 2, 3, 2; inner metatarsal tubercle oval, surface flat; outer metatarsal tubercle weakly visible.

Skin smooth, with pearly asperities on side of head and dorsal surfaces of head, back, limbs, and outer margin of foot; venter coursely granular; very weak dermal fringe on outer margin of toe V from base of foot to base of tip. Velvety, ovoid nuptial pad on dorsal and posterior margin of finger I.

Color of holotype in life. Iris uniformly bronze with small black reticulations; dorsum light brown with brown hourglass-shaped marking on top of head, continuing as stripe on back to sacrum; dorsal surfaces of limbs orangebrown with irregular, black crossbands, dorsal surfaces of digits bronze (matching iris); flank gray; irregular black band from tip of snout to axilla, as narrow band below canthus and eye but as enlarged spot over nostril and tympanum; irregular, large, black spots and reticulations on flank; ventral surfaces uniformly gray.

Color of holotype in preservative. Black coloration faded to brown; brown marking on top of head and back less distinct; bronze coloration on digits faded to brown.

Variation. Paratypes closely resemble holotype. NUOL 0 0 0 43 lacks a nuptial pad and has the smallest body size in the type series (SVL 15.5), and so is deemed immature. Females, eggs, larvae, and vocalizations are unknown. Measurements are summarized in Table 1 View TABLE 1 .

Molecules. The new species was recovered in both analyses as sister to T. lateriticum Bain, Nguyen & Doan 2009 , with a Bayesian posterior probability of 1.00 ( Fig. 2 View FIGURE 2 ). The holotype and sequenced paratype (NCSM 84683) differed by only a single insertion-deletion in the 16S gene fragment (and so had a p -distance of 0%). Four sequences of T. lateriticum (GenBank accession numbers LC 012848 View Materials –51) had p -distances of 0.33–4.40%. The new species and T. lateriticum (n =4) had p -distances of 10.54–10.81%. Bayesian inference of the trimmed alignment differed from that of the complete alignment only by failing to recover statistical support for the monophyly of Theloderma laeve and a sister relationship between the outgroup genera Kurixalus and Nasutixalus .

Distribution, natural history, and conservation. Theloderma lacustrinum sp. nov. is currently known only from the type and paratype localities ( Fig. 3 View FIGURE 3 ), where it was collected at night (1820–2215 h) on leaves 30–80 cm above the ground near two rocky streams (292–361 m elev.) in semi-evergreen forest that flow into the Nam Lik Reservoir ( Fig. 1 View FIGURE 1 ). The two known localities are approximately 5.7 air-km apart. We did not observe the new species at these localities during visits in April, July, and September 2015, suggesting that it may be seasonally active or most detectable during cooler, drier months (e.g., at lower heights in the forest canopy). The vicinity of the two known localities had not been surveyed for amphibians prior to construction of the hydroelectric dam, and thus it is not known how inundation from the reservoir may have impacted the range of the species.

Comparisons. Theloderma lacustrinum sp. nov. is most closely related to T. lateriticum ( Fig. 2 View FIGURE 2 ) from Lao Cai, Bac Giang, and Son La Provinces, Vietnam ( Bain et al. 2009, Nguyen et al. 2015), but is readily distinguished from T. lateriticum by having a light brown dorsum with dark markings (nearly uniformly red in lateriticum ), by having a uniformly gray venter (distinctly spotted in lateriticum ), and by having a bronze iris (deep brick-red in lateriticum ).

Theloderma lacustrinum View in CoL sp. nov. differs from all other Theloderma View in CoL by having adult males with SVL <21 mm, except T. baibengense ( Jiang, Fei & Huang 2009) View in CoL that has adult males with SVL 15.0–16.2, n =2 ( Jiang et al. 2009). However, T. lacustrinum View in CoL sp. nov. is readily distinguished from T. baibengense View in CoL by having a light brown dorsum with dark markings (dark with conspicuous white pattern in baibengense View in CoL ), by having a uniformly gray venter (distinctly contrasting marbled pattern in baibengense View in CoL ), and by having a bronze iris (reddish-brown in baibengense View in CoL ).

Twelve additional species of Theloderma View in CoL have small (sensu Rowley et al. 2011) adult body sizes, with SVL <35 mm: T. albopunctatum ( Liu & Hu 1962) View in CoL , T. andersoni ( Ahl, 1927) View in CoL , T. asperum ( Boulenger 1886) View in CoL , T. laeve ( Smith 1924) View in CoL , T. licin McLeod & Norhayati 2007 View in CoL , T. nebulosum Rowley, Le, Hoang, Dau & Cao 2011 View in CoL , T. palliatum Rowley, Le, Hoang, Dau & Cao 2011 View in CoL , T. petilum ( Stuart & Heatwole 2004) View in CoL , T. rhododiscum ( Liu & Hu 1962) View in CoL , T. stellatum Taylor 1962 View in CoL , T. truongsonense ( Orlov & Ho 2005) View in CoL , and T. vietnamense Poyarkov, Orlov, Moiseeva, Pawangkhanant, Ruangsuwan, Vassilieva, Galoyan, Nguyen & Gogoleva, 2015 View in CoL . Theloderma lacustrinum View in CoL sp. nov. differs from T. laeve View in CoL and T. truongsonense View in CoL by having dorsal asperities (absent in laeve View in CoL and truongsonense View in CoL ). Theloderma lacustrinum View in CoL sp. nov. differs from T. petilum View in CoL by lacking vomerine teeth (present in petilum View in CoL ) and by having relatively smaller finger discs, with the disc diameter of finger III ca. 40% of tympanum diameter (≥65% in petilum View in CoL ). Theloderma lacustrinum View in CoL sp. nov. differs from T. albopunctatum View in CoL , T. asperum View in CoL , T. baibengense View in CoL , T. licin View in CoL , and T. stellatum View in CoL by having a light brown dorsum with dark markings (dorsum dark with conspicuous white pattern in albopunctatum View in CoL , asperum View in CoL , baibengense View in CoL , and stellatum View in CoL , nearly uniformly brown or white in licin View in CoL ). Theloderma lacustrinum View in CoL sp. nov. differs from T. albopunctatum View in CoL , T. asperum View in CoL , T. licin View in CoL , T. nebulosum View in CoL , T. palliatum View in CoL , T. rhododiscum View in CoL , T. stellatum View in CoL , T. truongsonense View in CoL , and T. vietnamense View in CoL by having a uniformly gray venter (distinctly contrasting spotted, marbled or reticulated ventral pattern in albopunctatum View in CoL , asperum View in CoL , baibengense View in CoL , chuyangsinense, lateriticum View in CoL , licin View in CoL , nebulosum View in CoL , palliatum View in CoL , rhododiscum View in CoL , stellatum View in CoL , truongsonense View in CoL , and vietnamense View in CoL ). Theloderma lacustrinum View in CoL sp. nov. differs from T. andersoni View in CoL by lacking two yellow spots on flank (present in andersoni View in CoL ). Theloderma lacustrinum View in CoL sp. nov. differs from T. laeve View in CoL , T. nebulosum View in CoL , T. palliatum View in CoL , T. petilum View in CoL , and T. truongsonense View in CoL by having a uniformly colored iris (distinctly bicolored in laeve View in CoL , nebulosum View in CoL , palliatum View in CoL , petilum View in CoL , and truongsonense View in CoL ).

TABLE 1. Measurements (mm) of types of Theloderma lacustrinum sp. nov. Abbreviations defined in the text.

Measurement Holotype male n =1 All males n =5 Range; Mean ± SD Juvenile n =1
SVL 20.6 17.0–20.6; 18.8 ± 1.7 15.5
HDL 9.7 7.3–9.7; 8.3 ± 1.1 6.9
HDW 6.6 5.5–6.7; 6.2 ± 0.6 5.3
SNT 3.0 2.8–3.1; 3.0 ± 0.1 2.9
EYE 2.8 2.0–3.0; 2.5 ± 0.4 2.6
TMP 1.9 1.4–1.9; 1.7 ± 0.3 1.3
IOD 3.8 2.5–3.8; 3.2 ± 0.5 2.9
IND 1.8 1.6–1.8; 1.7 ± 0.1 1.6
SHK 12.0 9.7–12.0; 11.0 ± 0.9 8.5
TGH 10.9 9.3–11.1; 10.3 ± 0.7 8.2
FAL 10.2 8.4–10.2; 9.2 ± 0.8 7.3
HND 5.2 4.5–5.3; 4.9 ± 0.4 4.0
FTL 8.1 6.2–8.1; 7.1 ± 0.8 6.0
NCSM

North Carolina Museum of Natural Sciences

NUOL

National University of Laos

Kingdom

Animalia

Phylum

Chordata

Class

Amphibia

Order

Anura

Family

Rhacophoridae

Genus

Theloderma

Loc

Theloderma lacustrinum

Sivongxay, Niane, Davankham, Monekham, Phimmachak, Somphouthone, Phoumixay, Keochay & Stuart, Bryan L. 2016
2016
Loc

T. vietnamense

Poyarkov, Orlov, Moiseeva, Pawangkhanant, Ruangsuwan, Vassilieva, Galoyan, Nguyen & Gogoleva 2015
2015
Loc

T. nebulosum

Rowley, Le, Hoang, Dau & Cao 2011
2011
Loc

T. palliatum

Rowley, Le, Hoang, Dau & Cao 2011
2011
Loc

T. baibengense (

Jiang, Fei & Huang 2009
2009
Loc

T. licin

McLeod & Norhayati 2007
2007
Loc

T. truongsonense (

Orlov & Ho 2005
2005
Loc

T. petilum (

Stuart & Heatwole 2004
2004
Loc

T. albopunctatum (

Liu & Hu 1962
1962
Loc

T. rhododiscum (

Liu & Hu 1962
1962
Loc

T. stellatum

Taylor 1962
1962
Loc

T. andersoni (

Ahl 1927
1927
Loc

T. laeve (

Smith 1924
1924
Loc

T. asperum (

Boulenger 1886
1886
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