Kaloula laosensis Poyarkov, Orlov, Gorin & Milto 2024, sp. nov.

Kaloula laosensis Poyarkov, Orlov, Gorin & Milto sp. nov. Figs 2, 9 A, 10, 11, 12, Table 4 Chresonymy. Kaloula baleata [partim] — Orlov and Ananjeva (2007: 148); Nguyen et al. (2009: 94). Kaloula indochinensis [partim] — Chan et al. (2013: 334, 2014: 577); Teynié et al. (2014: 29); Chandramouli and Prasad (2018: 52); Poyarkov et al. (2021 b: 39); Holden (2023: 148). Holotype. ZISP 15284 (field label ZISP 199), adult male, Na Home Village, Bouphala District, near the border of Nakai-Nam Theun National Park, Khammouane Province, Laos, collected by N. L. Orlov, S. N. Nguyen, and K. D. Milto on June 18, 2009 (17.544528 ° N, 105.695278 ° E; elevation 174 m a. s. l.). Paratype (n = 1). ZMMU A-8144 (field label ZISP 200), adult female from the same location and with the same collection data as the holotype. Diagnosis. Kaloula laosensis sp. nov. is distinguished from its congeners by the following combination of morphological attributes: (1) medium size (SVL ranging 44.0– 54.8 mm); (2) eyes comparatively large (eye length comprising 75 % – 100 % of snout length); (3) dark-brown dorsally, with numerous irregular dark blotches forming pericloacal ring; (4) gray or beige ventrally with dense white mottling on belly and limbs; (5) orange triangular patch on either side of the neck posterior to eyes; (6) bright-orange axillary patch present; (7) orange inguinal patch present; (8) bright-orange butterfly-shaped blotch above cloaca present; (9) gray spot on tibiotarsal articulation present; (10) dark interorbital bar present; (11) enlarged, widened finger disks (7.8 % – 7.9 % of SVL), ca. 1.53 times wider than toe disks; (12) finger subarticular tubercle formula: 1: 1: 2: 2; (13) toe subarticular tubercle formula: 1: 1: 2: 2: 2; (14) three metacarpal tubercles, median metacarpal tubercle in contact with inner metacarpal tubercle; (15) two metatarsal tubercles, inner metatarsal tubercle ca. three times larger than outer metatarsal tubercle; (16) three small supernumerary tubercles at the basis of toes I, III, IV. Description of the holotype (Fig. 10). Adult male in a good state of preservation, habitus robust; head wider than long (HW / HL 1.19); snout projecting beyond lower jaw, truncated in dorsal and lateral views (Fig. 10 C); top of head flat; upper eyelid lacking supraciliary tubercles; eye length less than snout length (EL / SL 0.75) and less than interorbital distance (EL / IOD 0.77); pupils round; nostrils rounded, placed more towards the lateral sides of snout, located closer to tip of snout than to eye, relatively close to each other (IND / IOD 0.63); supratympanic fold flat, tubercular; tympanum not visible (Fig. 10 C); dorsal surfaces of body and limbs with sparse tubercules, getting denser backwards; ventral surfaces of body and limbs almost smooth (Fig. 10 A, B). Cloacal opening unmodified, directed posteriorly. Forelimbs relatively long, more than a half of hind limb length (FLL / HLL 0.63); hand long, comprising more than a half of lower arm length (HAL / LAL 0.6) and almost half of forelimb length (HAL / FLL 0.47); fingers rather robust, flattened in cross section; relative finger lengths: I <II <IV <III; no webbing between fingers; terminal digits flattened into very wide transversely expanded T-shaped disks (Fig. 10 E); finger subarticular tubercles distinct, protuberant, large and round, finger subarticular formula: 1: 1: 2: 2; metacarpal tubercles three (Figs 9 A, 10 E), inner metacarpal tubercle elongate, flattened; outer metacarpal tubercule oval, dilated, slightly bigger than inner (OPTL / IPTL 1.05), median metacarpal tubercle the smallest, oval-shaped, contacting both the inner and outer metacarpal tubercles (Figs 9 A, 10 E); hindlimbs robust, relatively short, not much longer than body length (HLL / SVL 1.12); relative toe lengths: I <II <V <III <IV; tarsal fold on inner surface of tarsus absent; tips of all toes widened, forming terminal oval-shaped disks (Figs 9 A, 10 D); all toe disks having dorso-terminal groves; the disk on toe IV the largest; toe webbing well developed between all toes, reaching disks at all toes except toe IV; webbing formula i 1.5-2 ii 1.5 - 2.5 iii 1.5 - 3 iv 3 - 2 v; toe subarticular tubercules distinct, rounded, protruding; toe subarticular formula: 1: 1: 2: 2: 2; two metatarsal tubercles, inner metatarsal tubercle elongated, oval, shovel-shaped; outer metatarsal tubercle smaller, rounded; three small supernumerary tubercles at the basis of toes I, III, IV (Figs 9 A, 10 D). Coloration. In life, dorsal surfaces of head and body dark brown with contrasting black spots and blotches; black interorbital bar between the upper eyelids; irregular black blotch on the snout; a series of black blotches forming a L-shaped chevron pattern in the scapular region; elongated black blotches on mid-dorsum, body flanks, and sacral area, forming a black pericloacal ring with irregular borders (Figs 2, 11); dorsal surfaces of limbs grayish brown with dark-brown to black blotches; flanks of body and lateral sides of head grayish brown; on lateral sides of belly getting dark-brown with white spots and blotches; pale orange patches on the neck posterior to eyes; bright reddish-orange axillary patch edged with dark brown; bright reddish-orange inguinal patch edged with black; bright reddish-orange patch above cloaca in the center of dark pericloacal ring (Fig. 2); small grayish-beige spots near tibiotarsal articulation; ventral surfaces of head and body gray, darker near the jaw; belly and ventral sides of limbs densely mottled with white spots and dots (Fig. 10); iris chocolate brown with copper sparkles dorsally and ventrally (Fig. 11). In preservation after 15 years of storage in ethanol, dorsal coloration faded to dark grayish-brown; dark markings on dorsum are well descernible; light patches became less pronounced and faded to yellowish or beige in color, though the coloration pattern generally remained unchanged (Fig. 10). Measurements of the holotype (in mm): SVL 44.0; HL 10.6; HW 12.6; SL 4.6; EL 3.3; N-EL 3.2; IND 2.7; IOD 4.3; UEW 2.4; FLL 27.6; LAL 21.7; HAL 13.0; HLL 49.3; TL 37.0; FL 25.4; IPTL 2.7; OPTL 2.8; 1 FL 7.5; 1 TOEL 7.3; OMTL 2.0; 3 FDD 3.4; 4 TDD 2.2. Variation. Morphometric variation of the type series is presented in Table 4. A dorsal view of a female paratype specimen is presented in Fig. 12. In general, the female paratype specimen agrees well with the description of the holotype, diverging only in body size, which is larger than in the holotype (SVL 54.8 mm). Female paratype ZMMU - A- 8144 has comparatively fewer dark markings on the dorsum (Fig. 12), but generally, the coloration pattern is similar to that of the holotype. Holden (2023: 148, fig. 152) published a photo of the new species from Laos as ‘ K. indochinensis, ’ which has bright-red axillary, inguinal, and pericloacal patches and lighter grayish-brown dorsal coloration. Tadpole morphology. Currently, data on the larval morphology of Kaloula laosensis sp. nov. are lacking. Distribution and natural history. Kaloula laosensis sp. nov. is currently reliably known only from two localities in the Khammouane Province of Laos; the distribution of the new species is shown in Fig. 5, and the locality information is detailed in Appendix 1. In Nakai-Nam Theun NP and in Hin Nam No NP, Khammouane Province, Laos, the new species was recorded from limestone evergreen tropical forests at relatively low elevations of ca. 100–300 m asl. The data on the natural history of Kaloula laosensis sp. nov. is scarce; it inhabits primarily lowland forests and is quite secretive, emerging only after heavy rains from June to September, when depressions in the forest floor are flooded and form temporary pools. The new species is likely associated with limestone karst landscapes of central Laos; the actual distribution of Kaloula laosensis sp. nov. is unknown, but we suppose that this species is likely to occur in adjacent provinces of Vietnam (Ha Tinh and Quang Binh), which harbor limestone forests similar in composition. Details about the new species’ reproductive biology and diet are unknown. Comparisons. Kaloula laosensis sp. nov. most closely resembles other members of the K. baleata species complex in overall morphology, and comparison with these species appears to be the most pertinent. Most specifically, the new species superficially resembles K. indochinensis, with which it was previously confused. From K. indochinensis, Kaloula laosensis sp. nov. can be distinguished by having relatively longer head in males (HL / SVL 0.24 [n = 1] by our data or mean 0.25 ± 0.1 [n = 4] reported by Chan et al. 2013) vs. mean 0.23 ± 0.1 [n = 18] by our data or [n = 25] reported by Chan et al. 2013); relatively wider disk of finger III in males (3 FDD / HAL 0.26 ± 0.1 [n = 1] vs. mean 0.23 ± 0.1 [n = 18]); relatively longer first toe in males (1 TOEL / FL 0.29 ± 0.1 [n = 1] vs. mean 0.26 ± 0.1 [n = 18]); by having three metacarpal tubercles with median metacarpal tubercle touching both the inner and outer metacarpal tubercles, see Fig. 9 A (vs. median metacarpal tubercle small, not touching the inner metacarpal tubercle, see Fig. 9 B); by having two subarticular tubercles on toe IV, see Fig. 9 A (vs. three well-developed subarticular tubercles, see Fig. 9 B); by having supranumerary tubercles at the basis of toes I, III, and IV, see Fig. 9 A (vs. supranumerary tubercles absent, see Fig. 9 B); by the presence of numerous contrasting black markings on dorsum (vs. absent or indistinct); and brownish dorsal coloration (vs. chocolate to dark grayish-brown). From K. baleata, Kaloula laosensis sp. nov. can be distinguished by having a relatively larger distance between nares in males (IND / HW 0.21 [n = 1] by our data or [n = 6] reported by Chan et al. (2013) vs. 0.18 ± 0.1 [n = 10] reported by Chan et al. (2013)); wider finger III disks in males (3 FDD 3.4 ± 0.1 mm [n = 1] by our data) or mean 3.1 ± 0.3 mm [n = 6] reported by Chan et al. (2013) vs. 1.7