Bioacoustics of Microhyla sriwijaya

Distribution and natural history. The new species is known from Belitung Island and the province of Lampung in southeastern Sumatra ( Fig. 1 ). The type specimens come from rural areas with oil palm plantations Kembiri village of Belitung. The holotype was collected while calling on the ground covered with grass and leaf litter, between a settlement and an oil palm plantation. During the day time animals were observed to be hiding under the litter or fallen logs, and emerged out by 18:30 h and started calling on leaf litter or soil close to small ponds. This new species of Microhyla is common and locally abundant on the island of Belitung, from west (Kembiri village, Mamblong district) to east (Batu Penyu village, Gantung district) and north (Tanjung Pandan, Tanjung Pandan district), in the urban, semi-urban, and rural areas. This species is always spotted close to water, either in small sewers with running water, small ponds for fish, or grass patches adjacent to beaches. The population from Canti, south slope of Gunung Rajabasa in Sumatra was found at coffee plantations and secondary forests. Due to vast development in both Belitung Island and Gunung Rajabasa of South Sumatra , habitat loss mainly due to plantations and associated anthropogenic activities is likely to be the main threat to this new species.

Morphological comparison. With members of Microhyla achatina species group ( Table 4 ): Microhyla sriwijaya sp. nov. is included genetically and morphologically as a member of the M. achatina group ( M. achatina , M. borneensis , M. daklakensis , M. fodiens , M. gadjahmadai , M. heymonsi , M. irrawady , M. kodial , M. malang , M. mantheyi , M. minuta , M. neglecta , M. nepenthicola , M. ninhthuanensis , M. orientalis , and M. pineticola ) and can be distinguished by its small adult size, nostril located towards lateral side of snout; finger and toe discs with dorsoterminal grooves, cover bifurcate distally, except in M. fodiens ; terminal phalanges of toes T-shaped, and a light yellowish-grey streak extending from posterior corner of eye to arm insertion (Garg et al ., 2019). A morphological comparison of the new species with all other members of the Microhyla achatina group are summarized in Table 4 , and an illustrated comparison specifically with the Indonesian members is depicted in Figure 6 . Microhyla sriwijaya sp. nov. differs from its sister taxon, M. orientalis from Indonesia by its stocky body (vs. slender), eye diameter nearly equal to internarial distance, ED/IND ratio 0.9–1.1 (vs. eye diameter larger than internarial distance, ED/IND ratio 1.3–1.6), thigh length nearly equal to foot length, TL/FOL ratio 1 (vs. thigh shorter than foot, TL/FOL ratio 0.8–0.9); absence of a mid-dorsal line or skin fold from the tip of snout to the vent (vs. present); comparatively longer hindlimbs, with tibiotarsal articulation of straightened limb projecting up to or beyond snout tip (vs. up to the level of eye); rudimentary foot webbing, reaching just above the first subarticular tubercles on all toes, I2 –– 2II2 –– 3 – III3 –– 4 – IV4 –– 3 – V (vs. up to the base first subarticular tubercles: I2–2 + II2–3III3–4IV4–3V); and reddish-brown or orangish colouration along concave margins on either side of the dorsum (vs. absent). Furthermore, a PCA of 40 morphometric characters of the two species revealed that Microhyla sriwijaya sp. nov. differs significantly from M. orientalis with respect to size-corrected characters such as HW, FAL, TL, SHL, TFOL, FL IV , FW II , and FW IV . A total of 76.9% percent variance was accounted by the first three principal components, with the first principal component accounting for 54.5% of the variance, followed by 13.3% and 9.09% of the variance covered by the second and third principal components, respectively. Graphical plotting of the first two principal components recovered the two taxa as separate clusters along PC1 ( Fig. 7 , Table 5 ). In general morphology, Microhyla sriwijaya sp. nov. also morphologically resembles M. kodial (endemic to India ) and M. minuta (endemic to Vietnam ) due to comparable snout-vent size, absence of a mid-dorsal line or skin fold from the tip of snout to the vent, and rudimentary webbing between toes. However, M. sriwijaya sp. nov. differs from M. kodial by its first finger shorter than one half of the second finger, F I <½F II (vs. longer, F I > ½F II ); comparatively longer hindlimbs, with tibiotarsal articulation of straightened limb projecting up to or beyond snout tip (vs. up to the level of eye); rudimentary webbing between toes, reaching just above the first subarticular tubercles on all the toes, I2 –– 2II2 –– 3 – III3 –– 4 – IV4 –– 3 – V (vs. absent or a trace of webbing below the first subarticular tubercles, I2–2 + II2–3III3–4IV4–3V); and reddish-brown or orangish colouration along concave margins on either side of the dorsum (vs. greyish-brown with olive-green markings). Further, M. sriwijaya sp. nov. differs from M. minuta by its stocky body (vs. slender); first finger shorter than one half of the second finger, F I <½ F II (vs. first finger long, almost equal, or slightly shorter than one half the length of the second finger); comparatively well-developed finger discs (vs. very weakly developed discs on the three outer fingers); comparatively longer hindlimbs, with tibiotarsal articulation of straightened limb projecting up to or beyond snout tip (vs. up to or just above the level of eye); and reddish-brown or orangish colouration along concave margins on either side of the dorsum (vs. bright yellow). Microhyla sriwijaya sp. nov. differs from M. achatina , M. fodiens , and M. gadjahmadai by its stocky body (vs. stout in all species), and smaller male snout vent size, SVL 12–15 mm (vs. larger, SVL 21–24 mm , SVL 20–29 mm , and SVL 18–22 mm , respectively). Specifically it also differs from M. achatina and M. gadjahmadai by the absence of a mid-dorsal line or skin fold (vs. present), and postorbital area and flank light brown with scattered spots or patches (vs. prominently blackish-brown). Individually, it further differs from M. achatina by snout obtusely rounded in dorsal view (vs. obtusely pointed); differs from M. gadjahmadai by its F I <½F II (FL I 0.5 mm , FL II 1.1 mm , vs. F I > ½F II , FL I 0.9 mm , FL II 1.3 mm ) ( Table 4 ). Microhyla sriwijaya sp. nov. specifically also differs from M. fodiens by the presence of finger and toe discs (vs. absent), and with dorso-terminal grooves, cover bifurcate distally (vs. absent). Microhyla sriwijaya sp. nov. differs from M. borneensis , M. malang , and M. mantheyi by its rudimentary foot webbing, reaching just above the first subarticular tubercles on all toes, I2 –– 2II2 –– 3 – III3 –– 4 – IV4 –– 3 – V (vs. moderate foot webbing, above the second subarticular tubercles on either side of toe IV in all the three species: I1–2II1–3III2½–3⅓IV3½–2V, I1–1⅔II1–1⅔III1–2½IV2½–1V, and I1–2II1–2III2–3IV3–1½V, respectively), and snout obtusely rounded in dorsal view (vs. obtusely pointed in all three species). Specifically it also differs from M. borneensis by well-developed first finger, FI <½FII (vs. greatly reduced to a nub), and absence of a mid-dorsal line or skin fold (vs. present); differs from M. malang by F I <½ F II (vs. F I > ½F II ), and absence of light or dark brown spots on margins of thigh and shank, and lateral surfaces of the head and lips (vs. present); differs from M. mantheyi by the absence of a mid-dorsal line or skin fold (vs. present). Microhyla sriwijaya sp. nov. differs from M. daklakensis , M. heymonsi , and M. ninhthuanensis by the absence of a mid-dorsal line or skin fold (vs. present); absence of a ‘()’-shaped dark marking at the centre of its dorsum (vs. present); and absence of blackish-brown lateral band (vs. absent). Microhyla sriwijaya sp. nov. differs from M. irrawaddy by having a stocky body (vs. slender); snout obtusely rounded in dorsal view (vs. acuminate); F I <½F II (vs. F I > ½F II ); and finger and toe discs with dorso-terminal groove, cover bifurcate distally (vs. absent). Microhyla sriwijaya sp. nov. differs from M. neglecta by its stocky body (vs. slender); snout obtusely rounded in dorsal view (vs. acuminate); first finger shorter than one half of the second finger, F I <½F II (vs. first finger longer than one half of the second finger, F I > ½F II ); absence of a mid-dorsal line or skin fold and a black spot at mid-dorsum (vs. present); and absence of dark lateral stripe from posterior margin of the eye to groin (vs. present). Microhyla sriwijaya sp. nov. differs from M. pineticola by its stocky body (vs. stocky, triangular); comparatively longer hindlimbs, with tibiotarsal articulation of straightened limb projecting up to or beyond snout tip (vs. below the snout tip); and absence of a mid-dorsal line or skin fold (vs. present). Microhyla sriwijaya sp. nov. differs from M. nepenthicola by its relatively larger adult male size, SVL 12–15 mm (vs. SVL 10–13 mm ); snout obtusely rounded in dorsal view (vs. obtusely pointed); relatively well-developed first finger, FI <½FII (vs. greatly reduced to a nub); absence of a mid-dorsal line or skin fold (vs. mid-vertebral ridge present); and rudimentary foot webbing, reaching just above the first subarticular tubercles on all toes, I2 –– 2II2 –– 3 – III3 –– 4 – IV4 –– 3 – V (vs. relatively more webbing, up to or slightly below the second subarticular tubercle on either side of toe IV). Microhyla sriwijaya sp. nov. (all the samples collected from Kembiri, Belitung, Indonesia) Museum No Status Sex SVL HW HL SL ED N-EL S-NL IOD UEW IND FAL HAL FL I FL II MZB Amph 31752 HT M 13.5 4.5 3.7 1.5 1.2 0.8 0.5 1.8 0.7 1.2 2.4 3.5 0.3 0.8 MZB Amph 31753 PT M 12.3 4.4 3.6 1.5 1.2 0.2 0.4 1.6 0.6 1.2 2.0 3.1 0.3 0.9 MZB Amph 31747 PT M 14.5 4.6 3.8 1.6 1.5 0.9 0.6 1.9 0.7 1.4 2.5 3.4 0.3 0.9 MZB Amph 31749 PT M 14.1 4.5 3.9 1.8 1.2 0.9 0.5 1.5 0.8 1.3 2.8 3.2 0.4 0.9 MZB Amph 31750 PT M 13.5 4.6 3.6 1.6 1.1 0.9 0.4 1.9 0.8 1.2 2.7 3.2 0.4 0.8 Mean 13.6 4.5 3.7 1.6 1.2 0.7 0.5 1.7 0.7 1.3 2.5 3.3 0.3 0.9 SD 0.8 0.1 0.1 0.1 0.2 0.3 0.1 0.2 0.1 0.1 0.3 0.2 0.1 0.1 Museum No MZB Amph 31752 Status HT Sex M FL III 2.2 FL IV 0.6 FD I 0.4 FW I 0.3 FD II 0.5 FW II 0.4 FD III 0.5 FW III 0.4 FD IV 0.4 FW IV 0.4 TL 7.6 SHL 8.2 FOL 7.5 TFOL 11.1 MZB Amph 31753 PT M 1.9 0.7 0.3 0.3 0.4 0.3 0.5 0.3 0.3 0.3 7.4 7.9 7.4 10.9 MZB Amph 31747 PT M 2.0 0.7 0.3 0.3 0.4 0.4 0.6 0.5 0.4 0.4 7.3 7.9 7.4 10.8 MZB Amph 31749 PT M 2.1 0.7 0.4 0.4 0.4 0.4 0.5 0.4 0.4 0.4 7.2 7.8 7.2 10.9 MZB Amph 31750 PT M 2.0 0.6 0.3 0.3 0.4 0.4 0.5 0.4 0.4 0.4 7.2 9.0 7.5 11.3 Mean 2.0 0.7 0.3 0.3 0.4 0.4 0.5 0.4 0.4 0.4 7.3 8.2 7.4 11.0 SD 0.1 0.1 0.1 0.0 0.0 0.0 0.0 0.1 0.0 0.0 0.2 0.5 0.1 0.2 Museum No MZB Amph 31752 Status HT Sex M TD I 0.4 TW I 0.4 TD II 0.6 TW II 0.5 TD III 0.7 TW III 0.5 TD IV 0.7 TW IV 0.5 TD V 0.5 TW V 0.4 IMTL 0.4 OMTL 0.2 MZB Amph 31753 PT M 0.4 0.3 0.5 0.4 0.5 0.4 0.5 0.4 0.4 0.3 0.4 0.2 MZB Amph 31747 PT M 0.4 0.4 0.5 0.4 0.5 0.4 0.6 0.4 0.5 0.4 0.4 0.3 MZB Amph 31749 PT M 0.4 0.4 0.5 0.4 0.6 0.4 0.7 0.4 0.5 0.4 0.5 0.3 MZB Amph 31750 PT M 0.4 0.4 0.5 0.4 0.7 0.5 0.7 0.4 0.5 0.4 0.5 0.2 Mean 0.4 0.4 0.5 0.4 0.6 0.4 0.6 0.4 0.5 0.4 0.4 0.2 SD 0.0 0.0 0.0 0.0 0.1 0.1 0.1 0.0 0.0 0.0 0.1 0.1 continued on the next page Museum No Status Sex SVL HW HL SL ED N-EL S-NL IOD UEW IND FAL HAL FL I FL II MZB Amph 31751 PT F 17.6 4.9 4.0 2.0 1.5 1.2 0.7 2.0 1.0 1.5 3.0 4.1 0.4 1.3 MZB Amph 31754 PT F 18.0 5.1 4.1 1.9 1.6 1.2 0.9 2.0 1.1 1.6 2.8 4.0 0.4 1.5 Mean 17.8 5.0 4.1 2.0 1.6 1.2 0.8 2.0 1.1 1.6 2.9 4.1 0.4 1.4 SD 0.3 0.1 0.1 0.1 0.1 0.0 0.1 0.0 0.1 0.1 0.1 0.1 0.0 0.1 Museum No MZB Amph 31751 Status PT Sex F FL III 2.2 FL IV 1.5 FD I 0.4 FW I 0.4 FD II 0.6 FW II 0.4 FD III 0.7 FW III 0.4 FD IV 0.6 FW IV 0.4 TL 9.4 SHL 9.5 FOL 9.3 TFOL 12.3 MZB Amph 31754 PT F 2.6 1.6 0.4 0.4 0.5 0.4 0.6 0.4 0.5 0.4 9.3 9.9 9.4 13.1 Mean 2.4 1.6 0.4 0.4 0.6 0.4 0.7 0.4 0.6 0.4 9.4 9.7 9.4 12.7 SD 0.3 0.1 0.0 0.0 0.1 0.0 0.1 0.0 0.1 0.0 0.1 0.3 0.1 0.6 Museum No MZB Amph 31751 Status PT Sex F TD I 0.7 TW I 0.5 TD II 0.8 TW II 0.6 TD III 0.8 TW III 0.6 TD IV 0.8 TW IV 0.6 TD V 0.6 TW V 0.4 IMTL 0.5 OMTL 0.3 MZB Amph 31754 PT F 0.6 0.4 0.7 0.5 0.8 0.5 0.9 0.5 0.6 0.4 0.5 0.3 Mean 0.7 0.5 0.8 0.6 0.8 0.6 0.9 0.6 0.6 0.4 0.5 0.3 SD 0.1 0.1 0.1 0.1 0.0 0.1 0.1 0.1 0.0 0.0 0.0 0.0 M. orientalis (all the male samples collected from Wongaya Gede, Bali, and single female PT from Batukaru, Bali, Indonesia) Museum No Status Sex SVL HW HL SL ED N-EL S-NL IOD UEW IND FAL HAL FL I FL II MZB Amph 20404 HT M 16.6 5.1 4.9 2.1 2.0 1.0 0.7 2.1 1.2 1.5 2.9 4.0 0.6 1.2 UIMZ 0037 RS M 17.1 4.9 4.3 2.2 2.0 1.1 0.7 1.7 1.0 1.3 2.7 4.1 0.7 1.1 UIMZ 0038 RS M 16.2 4.8 4.3 2.3 1.8 1.0 0.7 1.6 0.9 1.2 2.4 4.0 0.6 1.0 UIMZ 0039 RS M 16.7 4.7 4.2 2.3 1.9 1.0 0.8 1.6 1.0 1.2 2.5 4.0 0.7 1.0 UIMZ 0040 RS M 16.3 4.9 4.4 2.1 1.8 1.0 0.7 1.6 0.9 1.3 2.4 4.1 0.7 1.1 UIMZ 0041 RS M 17.5 5.1 4.4 2.4 2.0 1.1 0.8 1.7 0.9 1.4 2.6 4.0 0.6 1.1 Mean 16.7 4.9 4.4 2.2 1.9 1.0 0.7 1.7 1.0 1.3 2.6 4.0 0.7 1.1 SD 0.5 0.2 0.2 0.1 0.1 0.1 0.1 0.2 0.1 0.1 0.2 0.0 0.1 0.1 ......continued on the next page Museum No MZB Amph 20404 Status HT Sex M FL III 2.9 FL IV 1.5 FD I 0.3 FW I 0.3 FD II 0.4 FW II 0.3 FD III 0.6 FW III 0.4 FD IV 0.5 FW IV 0.4 TL 8.0 SHL 8.6 FOL 8.8 TFOL 12.5 UIMZ 0037 RS M 2.4 1.5 0.3 0.3 0.4 0.3 0.3 0.2 0.4 0.3 7.6 8.4 9.1 12.6 UIMZ 0038 RS M 2.4 1.4 0.2 0.2 0.3 0.2 0.4 0.3 0.4 0.3 7.4 8.1 8.9 11.9 UIMZ 0039 RS M 2.2 1.2 0.2 0.2 0.3 0.2 0.3 0.2 0.4 0.3 7.4 8.2 8.9 12.1 UIMZ 0040 RS M 2.3 1.3 0.2 0.2 0.4 0.3 0.4 0.3 0.4 0.3 7.5 8.2 9.0 12.2 UIMZ 0041 RS M 2.4 1.4 0.3 0.3 0.4 0.3 0.4 0.3 0.4 0.3 7.6 8.5 9.3 12.8 Mean 2.4 1.4 0.3 0.3 0.4 0.3 0.4 0.3 0.4 0.3 7.6 8.3 9.0 12.4 SD 0.2 0.1 0.1 0.1 0.0 0.0 0.1 0.1 0.0 0.0 0.2 0.2 0.2 0.3 Museum No MZB Amph 20404 Status HT Sex M TD I 0.3 TW I 0.3 TD II 0.4 TW II 0.3 TD III 0.5 TW III 0.4 TD IV 0.5 TW IV 0.4 TD V 0.4 TW V 0.4 IMTL 0.6 OMTL 0.3 UIMZ 0037 RS M 0.4 0.4 0.6 0.4 0.6 0.4 0.6 0.3 0.6 0.4 0.5 0.3 UIMZ 0038 RS M 0.3 0.3 0.4 0.3 0.5 0.4 0.6 0.3 0.6 0.5 0.4 0.2 UIMZ 0039 RS M 0.4 0.4 0.4 0.3 0.5 0.4 0.6 0.3 0.6 0.4 0.4 0.2 UIMZ 0040 RS M 0.4 0.4 0.5 0.3 0.6 0.4 0.7 0.4 0.6 0.4 0.5 0.3 UIMZ 0041 RS M 0.4 0.4 0.5 0.3 0.6 0.4 0.6 0.3 0.6 0.4 0.5 0.4 Mean 0.4 0.4 0.5 0.3 0.6 0.4 0.6 0.3 0.6 0.4 0.5 0.3 SD 0.0 0.0 0.1 0.0 0.1 0.0 0.1 0.0 0.1 0.0 0.1 0.1 Museum No Status Sex SVL HW HL SL ED N-EL S-NL IOD UEW IND FAL HAL FL I FL II MZB Amph 16529 PT F 18.8 5.4 5.0 2.2 2.0 1.2 0.8 2.0 1.0 1.6 3.3 4.5 0.6 1.2 FL III 2.9 FL IV 1.6 FD I 0.3 FW I 0.3 FD II 0.4 FW II 0.3 FD III 0.5 FW III 0.4 FD IV 0.5 FW IV 0.4 TL 8.8 SHL 9.3 FOL 10.2 TFOL 14.7 TD I 0.5 TW I 0.4 TD II 0.6 TW II 0.5 TD III 0.7 TW III 0.5 TD IV 0.7 TW IV 0.5 TD V 0.6 TW V 0.5 IMTL 0.5 OMTL 0.3 Species SVL (M) SVL (F) Body form Snout profile Skin in dorsum FL I vs FL II Disk on finger/toe Grooves on finger/toes M. sriwijaya sp. nov. 12.3–15.8 18.9–19.6 Stocky Rounded Smooth with few tubercles FL I <½FL II Present Present M. achatina 21.7–24.3 20.6–28.0 Stout Obtusely pointed Smooth or feebly tubercular FL I <½FL II Present Present M. borneensis 11.0–13.0 18.0–19.0 Stocky Obtusely pointed Smooth, small tubercles Nub/bulge Present Present M. fodiens 20.1–29.1 20.0–30.0 Stout Rounded Feebly tubercular FL I <½FL II Absent Absent M. gadjahmadai 18.2–21.3 20.4–24.5 Stout Rounded Low tubercles FL I> ½FL II Present Present M. heymonsi 16.5–22.0 18.0–26.5 Stocky Obtusely pointed Smooth FL I <½FL II Present Present M. irrawady 12.3–17.1 16.7–20.9 Slender Acuminate Granular FL I> ½FL II Present Absent M. kodial 16.9–17.4 18.0–20.4 Slender Rounded Tuberculated FL> ½FL I II Present Absent M. malang 18.7–22.2 19.0–23.4 Stocky Rounded Smooth FL I <½FL II Present Present M. mantheyi 15.0–29.2 14.8–24.1 Stocky Pointed Granular, feebly pustular FL I <½FL II Present Present M. minuta 14.7–15.9 15.7–17.2 Slender Bluntly rounded Granular, feebly pustular FL <½FL I II Present Present M. neglecta 17.2–19.5 17.8–23.0 Slender Acuminate Smooth with few tubercles FL I> ½FL II Present Present M. nepenthicola 10.6–12.8 17.9–18.8 Slender Obtusely pointed Smooth, small tubercles Nub/bulge Present Present M. orientalis 15.8–17.4 15.8–17.4 Slender Rounded Smooth or slightly tubercular FL I <½FL II Present Present M. pineticola 17.4–18.6 20.0–22.3 Stocky Rounded Feebly granular FL I <½FL II Present Present ......continued on the next page Species Vertebral Line/fold Tibiotarsal articulation reaches Webbing formula Distribution Sources M. sriwijaya sp. nov. Absent Up to snout tip I2––2II2––3–III3––4–IV4––3–V Indonesia Present study M. achatina Present Up to snout tip or beyond I2–2II2–3III3–4IV4–3–V Indonesia Atmaja et al ., 2019 ; Present study M. borneensis Absent Below snout tip I1-2II1-3III2½-3⅓IV3½-2V Malaysia Das & Haas 2010 ; Matsui 2011 M. fodiens Absent Below snout tip I1-2II1¾-3III2¾-3¾IV 4-2¾V Myanmar Poyarkov et al ., 2019 M. gadjahmadai Present Beyond snout tip I2––2II2––3–III3––4–IV4––3–V Indonesia Atmaja et al ., 2019 ; Present study M. heymonsi Present Below snout tip I2-2½II2-3III3-4IV4⅓-3V Indo-Burma and Sundaland Poyarkov et al ., 2014 , 2020; Hoang et al ., 2021 M. irrawady Absent Up to eye I2-3II2-3III3-4½IV4½-2¾V Myanmar Poyarkov et al ., 2019 M. kodial Absent Up to eye I2–2+II2–3III3–4IV4–3V India Vineeth et al ., 2018 ; Present study M. malang Absent Up to snout or just beyond I1–1⅔II1–1⅔III1–2½IV2½–1V Malaysia Matsui 2011; Present study M. mantheyi Absent Beyond snout tip I1-2II1-2III2-3IV3-1½V Thailand, Malaysia, Singapore Das et al ., 2007 ; Poyarkov et al ., 2020 M. minuta Absent Below snout tip In.a.-n.a.II2-3½III3-4IV4-3V Vietnam Poyarkov et al ., 2014 , 2020 M. neglecta Present Beyond snout tip I1½-2½II1¾-3III2¾-3¾IV3¾-2½V Vietnam Poyarkov et al ., 2020 M. nepenthicola Absent Below snout tip In.a.-n.a.II1-3III2-3IV3-2V? Malaysia Das & Haas 2010 ; Matsui 2011 M. orientalis Present Up to eye I2–2+II2–3III3–4IV4–3V Indonesia Matsui et al ., 2013 ; Present study M. pineticola Present Below snout tip I1½-2½II1¾-3III2¾-3¾IV4-2½V Vietnam Poyarkov et al ., 2014 , 2020 Variables PC1 PC2 PC3 PC4 PC5 PC6 HW/SVL -0.900461 0.264886 0.194873 -0.182310 -0.045821 -0.032671 HL/SVL -0.518120 0.725560 0.274562 0.068503 0.240832 -0.190326 SL/SVL 0.780684 0.193203 0.037034 -0.495871 0.043762 -0.256757 ED/SVL 0.855921 0.243151 0.238471 0.122784 0.072658 0.270255 N-EL/SVL 0.319781 -0.345883 -0.798888 0.258712 0.183744 -0.004211 S-NL/SVL 0.782463 -0.017801 0.047739 -0.111246 0.307455 0.278252 IUE/SVL -0.620926 0.502620 -0.122600 -0.355334 0.132402 0.362606 UEW/SVL 0.275824 0.462449 -0.320137 0.531620 0.290391 -0.316866 IND/SVL -0.819939 0.392683 -0.008295 0.111747 -0.244152 0.207975 FAL/SVL -0.732780 0.275245 -0.553467 -0.096340 0.057683 -0.181218 HAL/SVL -0.367559 -0.329124 0.460048 0.597109 0.319696 -0.162593 FL I /SVL 0.888512 0.046658 -0.011428 -0.068015 0.056817 -0.251856 FL II /SVL -0.016878 0.781512 0.504196 0.034938 -0.095350 -0.093364 FL /SVL III -0.304670 -0.793246 0.177858 -0.430409 -0.151005 -0.124048 FL IV /SVL 0.899144 0.312691 0.147204 0.015424 0.018326 -0.043519 FD I /SVL -0.880295 -0.049128 -0.107580 0.194915 -0.204716 -0.150018 FW /SVL I -0.827115 0.017178 -0.123601 0.248447 -0.330729 -0.229717 FD /SVL II -0.925543 -0.076780 0.099702 0.193220 -0.116935 -0.008727 FW II /SVL -0.949856 -0.059101 -0.244832 0.056283 -0.127400 0.030413 FD /SVL III -0.873610 0.375147 -0.072885 0.083840 0.010782 -0.129631 FW /SVL III -0.861057 0.157730 -0.318295 0.087984 0.046812 -0.142703 FD IV /SVL -0.466872 0.540008 -0.440770 -0.290746 0.406454 0.104866 FW IV /SVL -0.867366 0.251744 -0.318321 -0.162045 0.189320 0.080612 TL/SVL -0.929190 0.142847 0.294657 -0.016794 0.054573 -0.109318 SHL/SVL -0.925517 -0.058469 0.226017 0.178478 0.052630 0.126360 FOL/SVL -0.277710 0.287347 0.710868 -0.512174 0.172431 -0.135439 TFOL/SVL -0.876353 0.124829 0.427360 -0.051578 0.025947 -0.035512 TD I /SVL -0.847938 -0.223151 0.154857 -0.269615 -0.246019 0.001463 TW I /SVL -0.638232 -0.217459 -0.328493 -0.564100 -0.086188 0.131346 TD /SVL II -0.870915 -0.286209 0.149709 0.023589 -0.175565 -0.042411 TW II /SVL -0.943920 -0.117020 0.087207 -0.112557 0.030128 0.009699 TD III /SVL -0.802770 -0.418638 0.015386 0.277690 0.014961 0.242009 TW /SVL III -0.891448 -0.168878 0.153834 0.077810 0.297764 0.152606 TD IV /SVL -0.803917 -0.473829 -0.110500 0.099048 0.182572 0.036923 TW IV /SVL -0.946014 -0.010557 0.117883 0.184936 0.129511 -0.038253 TD /SVL V -0.239995 -0.657284 0.014974 -0.525235 0.368478 -0.193669 TW V /SVL -0.565525 -0.134791 -0.125333 -0.142885 0.704300 -0.207172 IMTL/SVL -0.485038 0.625460 -0.217519 -0.050840 -0.053476 0.309319 OMTL/SVL -0.100883 0.337993 -0.436387 -0.318674 -0.447635 -0.341160 Eigenvalue 21.26978 5.18912 3.54574 2.85136 1.99247 1.25233 % Total variance 54.53791 13.30544 9.09165 7.31117 5.10891 3.21110 Cumulative Eigenvalue 21.26978 26.45890 30.00465 32.85600 34.84848 36.10081 Cumulative % 54.5379 67.8433 76.9350 84.2462 89.3551 92.5662 ......continued on the next page Variables PC7 PC8 PC9 PC10 PC11 PC12 HW/SVL -0.035225 0.101001 -0.161420 0.059899 0.041819 -0.04232 HL/SVL 0.052767 -0.073385 0.024244 -0.043182 0.130316 0.056649 SL/SVL 0.175101 0.015432 -0.015881 0.052086 0.015888 -0.06316 ED/SVL -0.058869 -0.151342 0.135475 0.030667 -0.10835 0.024739 N-EL/SVL -0.121142 -0.105230 0.021031 0.073606 0.067934 0.054286 S-NL/SVL 0.136403 -0.287107 0.258284 -0.132758 0.020047 -0.12269 IUE/SVL -0.099313 0.196439 -0.028107 0.141273 -0.01411 -0.04603 UEW/SVL -0.207963 0.235722 0.094067 -0.124215 -0.11386 -0.06455 IND/SVL 0.159063 -0.124073 -0.094998 -0.063455 0.014815 0.064147 FAL/SVL 0.028530 0.093723 0.036683 -0.052182 -0.14128 0.043254 HAL/SVL -0.230800 -0.015768 -0.002608 0.004147 0.065161 -0.04433 FL I /SVL -0.298873 0.112773 0.038580 -0.140181 0.065040 0.097678 FL II /SVL -0.092262 -0.243458 0.043944 -0.133937 -0.04070 0.162479 FL /SVL III 0.040443 -0.002267 -0.090428 0.050768 0.018794 0.100560 FL IV /SVL -0.106244 -0.062871 0.059850 0.193767 0.006099 0.114986 FD I /SVL 0.157687 -0.009673 0.259830 0.122650 -0.01749 -0.02945 FW /SVL I 0.185554 -0.067192 0.076703 -0.002965 -0.17724 0.013392 FD /SVL II -0.139213 -0.033559 0.167097 0.103389 0.127593 -0.03247 FW II /SVL -0.061798 -0.082584 0.014378 -0.014192 0.014062 0.052632 FD /SVL III 0.212589 -0.072180 -0.090567 -0.029176 0.085705 -0.00233 FW /SVL III 0.229603 -0.136919 -0.093587 -0.016977 0.143614 0.030938 FD IV /SVL 0.004461 0.055257 0.148515 0.042827 0.087670 0.027548 FW IV /SVL 0.092045 0.055105 0.047797 -0.015759 0.006931 0.016840 TL/SVL 0.022451 0.105163 0.009043 -0.000829 -0.00672 -0.04975 SHL/SVL 0.080637 -0.041841 -0.094010 -0.082259 -0.11964 -0.01239 FOL/SVL -0.100219 0.017035 0.063779 0.074873 0.059257 -0.03251 TFOL/SVL -0.092236 0.041592 -0.040825 0.002058 -0.09321 -0.09270 TD I /SVL -0.077968 0.072696 0.048842 -0.239213 -0.04295 -0.03446 TW I /SVL -0.112891 0.044939 0.191987 -0.192404 0.069303 0.033601 TD /SVL II -0.190062 -0.006937 0.199404 0.125199 -0.03896 0.104281 TW II /SVL -0.001266 0.117727 0.197802 0.102669 -0.07709 0.067633 TD III /SVL -0.175023 -0.077148 -0.019720 0.072685 0.034579 -0.02662 TW /SVL III 0.039950 -0.125586 0.080027 -0.031108 -0.09137 -0.04516 TD IV /SVL -0.182180 -0.036404 -0.156936 -0.079965 0.083028 0.007468 TW IV /SVL -0.061161 -0.003039 0.060255 -0.055275 0.166553 -0.02089 TD /SVL V -0.134498 -0.168929 -0.014714 -0.065875 -0.09238 0.035827 TW V /SVL 0.086743 -0.165924 -0.128076 0.119211 -0.14326 0.027128 IMTL/SVL -0.414337 -0.079070 -0.192196 0.010029 -0.09574 0.031104 OMTL/SVL -0.336800 -0.339241 -0.009340 0.076988 0.001043 -0.17971 Eigenvalue 0.96398 0.60587 0.51191 0.35429 0.28658 0.17656 % Total variance 2.47174 1.55350 1.31259 0.90845 0.73483 0.45272 Cumulative Eigen- 37.06479 37.67065 38.18256 38.53686 38.82344 39.00000 value Cumulative % 95.0379 96.5914 97.9040 98.8125 99.5473 100.0000 Microhyla orientalis Microhyla sriwijaya sp. nov . Property SD Range (min-max) Property SD Range (min-max) Temporal Call Duration (s) 57.8 12.8 51.9–63.0 (30.4–76.9) Call Duration (s) 46.9 15.4 31.8–62.8 (29.0–66.7) properties Call Rise Time (ms) 18.0 11.8 7.1–25.8 (0.8–49.2) Call Rise Time (ms) 12.2 14.7 0.5–32.7 (0.1–30.1) Call Fall Time (ms) 39.2 10.4 34.6–44.7 (23.2–60.7) Call Fall Time (ms) 34.8 13.2 26.8–50.8 (2.1–65.5) Pulses Per Call* 4.0 3.0–4.0 3.0–5.0 (3.0–5.0) Pulses Per Call* 2.0 2.0-3.0 2.0–3.0 (2.0–3.0) Pulse Rate (Pulses/Second) 53.5 9.8 48.3–63.1 (40.5–76.4) Pulse Rate (Pulses/Second) 34.7 1.6 32.2–36.0 (31.1–38.9) Pulse Period (ms) 21.8 2.5 19.8–23.3 (8.1–25.3) Pulse Period (ms) 28.7 2.0 27.6–32.0 (25.7–33.7) Pulse Duration (ms) 5.3 0.8 4.6–6.7 (3.6–7.6) Pulse Duration (ms) 4.4 1.0 2.9-5.7 (2.4–6.1) Pulse Rise Time (ms) 0.9 0.2 0.7–1.2 (0.6–1.3) Pulse Rise Time (ms) 0.8 0.1 0.7-0.8 (0.5–0.9) Pulse 50 Rise Time (ms) 0.7 0.1 0.6–0.8 (0.5–0.9) Pulse 50 Rise Time (ms) 0.5 0.1 0.4–0.6 (0.3–0.6) Pulse Fall Time (ms) 4.3 0.7 3.7–5.6 (2.8–6.4) Pulse Fall Time (ms) 3.7 1.1 2.1–4.9 (1.5–5.3) Pulse 50 Fall Time (ms) 3.7 0.7 3.0–5.0 (2.3–5.9) Pulse 50 Fall Time (ms) 3.1 1.0 1.8–4.2 (1.4–4.6) Spectral property Overall Dominant Frequency (kHz) 3.7 0.1 3.6–3.8 (3.4-3.9) Overall Dominant Frequency (kHz) 4.3 0.1 4.1–4.5 (3.9–4.5) *Because pulses are indivisible units, we report the median and inter-quartile ranges based on individual medians (prior to temperature correction) in place of means and standard deviations. Variables PC1 PC2 PC3 PC4 PC5 PC6 PC7 PC8 PC9 Call Duration (s) -0.698436 -0.050188 0.565199 0.428284 0.049734 0.046375 0.038551 -0.010019 0.024090 Call Rise Time (s) -0.357780 -0.489131 0.792141 0.012499 -0.060258 0.021590 -0.015678 0.011039 -0.025219 Call Fall Time (s) -0.433322 0.619204 -0.339238 0.534295 0.146134 0.068046 0.045532 0.012694 -0.006762 Number of Pulses per Call -0.947972 -0.242930 0.042684 0.153640 -0.021142 -0.103225 0.075958 0.002100 -0.005530 Pulse Rate (pulses/s) -0.900095 -0.228614 -0.312740 -0.138542 -0.033676 -0.078248 0.107446 -0.023533 -0.034765 Overall Dominant Frequency (kHz) 0.886350 0.231117 0.154545 -0.141287 -0.267290 0.140031 0.160551 0.017092 0.000707 Pulse Period (s) 0.820511 0.459359 0.189515 0.253850 -0.094567 0.018149 -0.049292 -0.041789 -0.044116 Pulse Duration (ms) -0.772272 0.590879 0.135085 -0.182285 -0.030953 0.000140 -0.031002 0.030517 -0.011489 Pulse Rise Time (ms) -0.755229 -0.085203 -0.278153 0.190889 -0.550434 0.021173 -0.071048 0.006838 0.006431 Pulse 50 Rise Time (ms) -0.832741 -0.381712 -0.209142 -0.156276 0.126671 0.274515 -0.030433 -0.015765 -0.009873 Pulse Fall Time (ms) -0.699454 0.646240 0.191076 -0.226938 0.059105 -0.003397 -0.021255 0.031493 -0.013365 Pulse 50 Fall Time (ms) -0.690352 0.627862 0.215257 -0.271646 -0.069341 -0.006705 0.014349 -0.057986 0.025604 Eigenvalue 6.797320 2.314825 1.443651 0.815635 0.437710 0.119826 0.056919 0.008561 0.005553 % Total variance 56.64433 19.29021 12.03042 6.79696 3.64759 0.99855 0.47432 0.07134 0.04627 Cumulative Eigenvalue 6.79732 9.11214 10.55580 11.37143 11.80914 11.92897 11.98589 11.99445 12.00000 Cumulative % 56.6643 75.9345 87.9650 94.7619 98.4095 99.4081 99.8824 99.9537 100.0000 Comparison with Indonesian species outside the Microhyla achatina group. The new species cannot be confused with any other known Microhyla members from Indonesia , outside the Microhyla achatina species group ( M. palmipes , M. superciliaris , M. berdmorei , and M. fissipes ). It differs from all these four species in having reddishbrown or orangish colouration along concave margins on either side of the dorsum (vs. absent); and irregular light or dark spots on the flanks (vs. bold or diffused dark stripe extending from the snout, behind the eye, or mid-body, through the flank or groin). Microhyla sriwijaya sp. nov. also specifically differs from the species with having an overlapping sie range, as discussed below. Comparison with similar-sized members (SVL 12–20 mm ) outside the Microhyla achatina group. Microhyla sriwijaya sp. nov. (SVL 12–20 mm ) can be differentiated from other congeners outside the Microhyla achatina group, which have with the following overlapping size ranges: M. beilunensis (male 19–24 mm , female 26–29 mm ), M. butleri (male 20–25 mm , female 21–26 mm ), M. chakrapani (male 17–22 mm , female 23–24 mm ), M. darreli (male 15–16 mm , female 17 mm ), M. fanjingshanensis (male 19–23 mm , female 22–23 mm ), M. fissipes , (male 18–28 mm , female 20–28 mm ), M. karunaratnei (male 13–19 mm , female 19–21 mm ), M. kuramotoi (male 23–28 mm , female 28–35 mm ), M. laterite (male 14–16 mm , female 18–19 mm ), M. maculifera (male 12–14, female 11.8 mm ), M. mixture (male 17–25 mm , female 25–27 mm ), M. mukhlesuri (male 16–24 mm , female 17–26 mm ), M. mymensinghensis (male 14–24 mm , female 20–25 mm ), M. nilphamariensis (male 17–24, female 20–25 mm ), M. ornata (male 15–23 mm , female 22–25 mm ), M. palmipes (male 13–16 mm , female 17–19 mm ), M. sholigari (male 16–18 mm , female 17–19 mm ), M. superciliaris (male 12.7 mm , female 12 mm ), M. taraiensis (male 20–22 mm , female 24 mm ), M. tetrix (male 10–14 mm , female 15–18 mm ), and M. zeylanica (male 15–19, female 16–22 mm ). It differs from M. butleri , M. darreli , M. karunaratnei , M. laterite , M. sholigari , M. superciliaris , M. tetrix , and M. zeylanica by nostrils placed towards the lateral side of the snout (vs. towards the dorsal side of the snout); rudimentary foot webbing, reaching just above the first subarticular tubercles on all toes, I2 –– 2II2 –– 3 – III3 –– 4 – IV4 –– 3 – V (vs. relatively more webbing in all these species, well above the first subarticular tubercle and maximum up to the second subarticular tubercle on either side of toe IV); and absence of a mid-dorsal line or skin fold (vs. present). Microhyla sriwijaya sp. nov. differs from M. beilunensis , fanjingshanensis , M. fissipes , M. kuramotoi , M. chakrapani , M. mixtura , M. mukhlesuri , and M. mymensinghensis by its finger and toe discs with dorso-terminal groove, cover bifurcate distally (vs. absent, except in M. kuramotoi and M. mixtura ); inner metatarsal tubercle rounded (vs. elongate); absence of a mid-dorsal line or skin fold (vs. present); and irregular light or dark spots on the flanks (vs. a prominent dark lateral band extending from the posterior corner of eye to flank). Microhyla sriwijaya sp. nov. differs from M. nilphamariensis , M. ornata , and M. taraiensis by its finger and toe discs with dorso-terminal grooves, cover bifurcate distally (vs. absent); weakly developed inner and outer metatarsal tubercles (vs. distinct); irregular light or dark spots on the flanks (vs. a prominent dark lateral band behind the posterior corner of eye to flank). Microhyla sriwijaya sp. nov . differs from M. palmipes by its nostrils placed towards the lateral sides of the snout (vs. towards the dorsal side of the snout); finger and toe discs with dorso-terminal groove, cover bifurcate distally (vs. circum-marginal grooves); and absence of a mid-dorsal line or skin fold (vs. present). Microhyla sriwijaya sp. nov . differs from M. maculifera by its finger and toe discs with dorso-terminal grooves, cover bifurcate distally (vs. absent); and two metatarsal tubercles (vs. one metatarsal tubercle). Comparison with larger-sized members (SVL 21–33 mm ) outside the Microhyla achatina group. Microhyla sriwijaya sp. nov. can be differentiated from all other congeners outside the Microhyla achatina group, which have a comparatively larger snout-vent length (SVL) as follows. It differs from the following species in having a small snout-vent size, SVL male 12–15, female 17–18 mm (vs. larger: M. aurantiventris : male 25–27 mm , female 30 mm ; M. okinavensis : male 22–29, female 26–31 mm ; M. berdmorei : male 23−33 mm , female 26−45 mm ; M. picta : male 25–30 mm , female 27–34 mm ; M. pulchra : male 22–29 mm , female 26–34 mm ; M. eos : male 21 mm , female 26–28 mm ; M. mihintalei : male 21–27 mm , female 24–25 mm ; M. rubra : male 24–29, female 30–31 mm ). Microhyla sriwijaya sp. nov. specifically also differs from M. aurantiventris by the tibiotarsal articulation of its adpressed limb reaching beyond snout tip (vs. tibiotarsal articulation up to eye); absence of a mid-dorsal line or skin fold (vs. present); and belly yellowish-grey or with blue tinge (vs. orange-yellow). It differs from M. okinavensis by its finger and toe discs with dorso-terminal groove, cover bifurcate distally (vs. absent); absence of a mid-dorsal line or skin fold (vs. present); and inner metatarsal tubercle rounded (vs. elongated). It differs from M. berdmorei by rudimentary foot webbing (vs. fully webbed); and differs from M. mihintalei , M. picta , and M. rubra by finger and toe tips dorsoterminal groove, cover bifurcate distally (vs. finger and toe tips without grooves); and inner and outer metatarsal tubercles not shovel-shaped (vs. shovel-shaped). It differs from M. eos by its finger and toe tips with dorso-terminal groove, cover bifurcate distally (vs. finger and toe discs with dorso-terminal grooves, cover rounded distally); and by rudimentary foot webbing, I2 –– 2II2 –– 3 – III3 –– 4 – IV4 –– 3 – V (vs. more, I1½–2 + II1⅔–3 – III2½–4 – IV4 –– 1½V). It further differs from M. pulchra by the presence of discs on finger and toe tips (vs. absent); and finger and toe tips dorso-terminal groove, cover bifurcate distally (vs. absent). Call characteristics and acoustic comparison. The measures of central tendency and dispersion for 13 studied acoustic properties from 100 advertisement calls recorded from five individuals of Microhyla sriwijaya sp. nov. and M. orientalis are shown in Table 6 . In both species, typical advertisement calls were relatively short with a pulsatile temporal structure ( Fig. 8 ). The call and pulse characteristics of both the species are described below. Microhyla sriwijaya sp. nov. Advertisement calls typically ranged between 31.8–62.8 ms in duration. On an average, the interval between two calls was 1.3 ± 5.1 s . The call rise time was short (= 12.2 ms ± 14.7 ms) and call fall time was relatively longer (= 34.8 ms ± 13.2ms). The advertisement calls had a pulsatile temporal structure and consisted of about 2 to 3 pulses. Pulses were typically produced at a rate of 32.2 to 36.0 pulses/second with a mean pulse period of 28.7 ms. The individual pulses of a call were about 4.4 ms in duration. Pulses had a short rise time (= 0.8 ms) and reached 50% of the maximum amplitude in 0.5 ms. The pulse fall time (= 3.7 ms) was nearly 10 times longer than the rise time. The pulse decreased to 50% of its maximum amplitude in nearly 3.1 ms before the end of the pulse. The spectrum was characterized by a single broad peak with mean dominant frequency of 4.3 kHz ( Fig. 8 ; Table 6 ). Microhyla orientalis . Advertisement calls typically ranged between 51.9–63.0 ms in duration. On an average, the interval between two calls was 0.6 ± 0.3 s . The call typically reached its full amplitude in about 18 ms (rise time) and decreased in amplitude over the last 39.2 ms (fall time). The call comprised of 3 to 5 pulses produced at a rate of 48.3–63.1 pulses/second. The pulse period of the call was 28.1 ms. The individual pulses of a call were about 5.3 ms in duration. Pulses had a short rise time (= 0.9 ms), with pulse reaching 50% of the maximum amplitude in 0.6 ms. The pulse fall time (= 4.3 ms) was nearly 5 times longer than the rise time. The pulse decreased to 50% of its maximum amplitude in nearly 3.7 ms before the end of the pulse. The spectrum was characterized by a single broad peak with mean dominant frequency of 3.7 kHz ( Fig. 8 ; Table 6 ). Call comparison between Microhyla sriwijaya sp. nov. and M. orientalis . The calls of Microhyla sriwijaya sp. nov. differed from those of M. orientalis by their relatively shorter call duration, 46.9 ms (vs. longer, 57.8 ms); relatively less number of pulses, 2.0 (vs. more number of pulses, 4.0), delivered at slower rate, 34.7 pulses/s (vs. faster rate, 53.5 pulses/s); and a higher overall dominant frequency of 4.3 kHz (vs. lower 3.7 kHz) ( Fig. 8 ; Table 6 ). The calls of M. sriwijaya sp. nov. and M. orientalis were also well differentiated based on statistical analyses of their acoustic properties. The first three PCA factors with eigenvalues> 1.0 explained 87.9% of the variation between the two species ( Table 7 ). The two species also formed considerably distinct clusters on factor planes recovered using the first two PCA factors, supporting distinction of the new species based on acoustic properties ( Fig. 7 ). Discriminant function analysis using the first three PCA factors as input resulted in 100% individuals ( five male specimens each) being classified into their respective species. The DFA generated a single discriminant function (root) that had an eigenvalue> 1.0, and explained 100% of the variation among the species.