Deskripsieng
Description of topotype, male, MZB Amph 27242 (measurements in mm). A small-sized Micryletta (SVL 20.5); head wider (HW 5.7) than long (HL 5.1); snout nearly rounded in dorsal and ventral view, acute in lateral view, its length (SL 2.1) slightly shorter than horizontal diameter of the eye (EL 2.3); loreal region acute with round- ed canthus rostralis; interorbital space flat, wider (IOD 2.7) than the upper eyelid (UEW 1.1) and internarial distance (IND 1.4); distance from nostril to tip of snout (S – NL 0.7) shorter than distance from nostril to the eye (N – EL 1.5); tympanum diameter (TD 0.7) shorter than eye length (EL 2.3); distance from nostril to the eye (N-EL 1.5) longer than distance from tympanum to the eye (T-EL 0.4); internarial distance (IND 1.4) shorter than interorbital distance (IOD 2.7); tympanum weakly-developed, supratympanic fold extending from posterior corner of eye to the shoulder weakly-developed; vomerine teeth absent; tongue small, oval, without papillae. Forelimbs slender, length (FLL 13.2), forearm (FAL 4.4) shorter than hand length (HAL 5.0); lower arm and hand length (LAL 9.6), longer than hand length (HAL 5.0); relative length of fingers: I <II <IV <III (FL I 1.5, FL II 1.9, FL III 3.0, FL IV 2.0); fingers free of webbing; supernumerary tubercle prominent; nuptial pad absent; subarticular tubercles well developed, rounded, all present; three palmar tubercles: inner palmar tubercle oval (IPTL 0.4), smaller than outer palmar tubercle (OPTL 0.5); tips of all fingers rounded, slightly dilated. Hindlimbs slender, length (HLL 29.7); tibia slightly longer (TL 9.2) than foot length (FL 8.9); relative length of toes: I <II <V <III <IV; tips of toes rounded, dilated; supernumerary tubercles absent; subarticular tubercles well developed; toes free of webbing; inner metatarsal tubercle present, outer metatarsal tubercle absent. Skin. Skin of dorsum smooth to shagreened, covered with small scattered tubercles; ventral surfaces smooth. Colour. Considerable colour differences exist between adults and sub-adults. Adult male, in life. Dorsum brownish-grey with a silver tinge and irregular blackish-brown blotches of variable size; upper eyelids and snout with a greenish-tinge; discontinuous blackish-brown lateral streak from tip of the snout to near the groin; lateral surfaces of belly light brown with greyish-white spots; flanks light brown with blackish-brown spots; silvery-grey line along the margins of upper lip; fore- and hind limbs brownish-grey with irregular light brown spots and blotches; fingers III and IV, and toes IV and V brownish-grey with faint cross bands; fingers I and II, and toes I – III light violet grey; iris bicoloured, light golden brown anteriorly and dark brown posteriorly. Ventrally, throat light reddish-grey with blackish-brown margins (calling male); chest and belly light reddish-grey with faint light grey scattered spots especially towards the margins; fore- and hindlimbs light violet grey. Adult male, in preservation. Dorsum brownish-grey with irregular dark brown blotches of variable size; discontinuous dark brown lateral streak from tip of the snout to near the groin; lateral surfaces of belly light brown with grey spots; fore- and hind limbs light grey with irregular light brown spots and blotches. Ventrally, throat light brown with dark brown margins; chest and belly light greyish-brown with faint grey scattered spots especially towards the margins; fore- and hindlimbs light greyish-brown. Sub-adult (MZB Amph 23570), in life. Dorsum, including fore- and hindlimbs, violet grey, light grey or dark grey with irregular golden yellow spots; lateral surfaces of head and belly blackish-brown; margins of upper lip with white spots; a light golden yellow streak extending from either side of the snout running up to the posterior end of upper eyelids; dorsal margins of snout and flanks dark brown with yellowish-grey spots. Ventrally, throat flesh white; chest flesh red with scattered white spots; belly flesh white; fore- and hind limbs light flesh red with a light violet tinge (Figure 3). Variations. MZB Amph 8542: Dorsal and lateral markings less prominent and lighter in colour compared to MZB Amph 27242. Morphological comparison. Micryletta inornata cannot be confused with any other known microhylid frog found in the region due to a combination of characters such as small snout-vent size (<SVL 20.5 mm), finger and toe tips rounded without dorso-terminal grooves, absence of webbing between fingers and toes, presence of inner metatarsal tubercle and absence of outer metatarsal tubercle. This species is also the only known member of the genus Micryletta currently known to occur in Sumatra, and could presumably also be endemic to the island. There are currently no available synonyms under M. inornata that originate from Sumatra. Since Micryletta inornata is the type species of the genus, in order to facilitate future studies, a comparison with all known members of the genus is provided below. A detailed comparison of morphological characters is also tabulated in Table 4. Micryletta inornata differs from M. steinegeri by its smaller snout-vent size in males, SVL 16.8 – 20.5 mm, N = 3 (vs. SVL 23.0 – 24.0 mm, N = 3); tibiotarsal articulation of adpressed limb reaching up to the level of eye (vs. reaching up to the level of tympanum); webbing between toes absent (vs. rudimentary webbing); dorsum brownishgrey with a silver tinge (vs. dark grey to violet, based on Poyarkov et al. [2018]); and ventral surfaces light reddishgrey without mottling (vs. with mottling).
Sumber: Rediscovery of Micryletta inornata (Boulenger, 1890) from Sumatra: redescription, molecular identity, and taxonomic implications
