Rana sinica Ahl, 1925

BAIN, RAOUL H., LATHROP, AMY, MURPHY, ROBERT W., ORLOV, NIKOLAI L. & CUC, HO THU, 2003, Cryptic Species of a Cascade Frog from Southeast Asia: Taxonomic Revisions and Descriptions of Six New Species, American Museum Novitates 3417, pp. 1-60 : 30-32

Rana sinica Ahl, 1925

Figure 10

HOLOTYPE: ZMB 9785 an adult female from China.

DIAGNOSIS: Rana sinica is characterized by a combination of the following attributes: (1) body dorsoventrally compressed; (2) SVL of single mature female is 66.6 mm, males unknown; (3) vomerine teeth in rows oblique to choanae; (4) lip­stripe absent; (5) head not broad, snout rounded in dorsal view; (6) tympanum round, indistinct, covered by a layer of skin, TMP:EYE 0.52; (7) supratympanic fold weak; (8) dorsal skin smooth flanks weakly granular, dorsolateral folds absent, venter smooth; (9) dorsum bronze­green with irregular indistinct spots and blue­gray flanks, legs with black bands; cloacal region marbled black with white; (10) median callous pad on finger III almost to proximal tubercle; (11) disks on fingers and toes slightly enlarged (<2× base of phalanges); (12) feet fully webbed on II, III, IV; I and V without lateral web fringes, webbing light gray in alcohol; (13) subarticular tubercles and inner metatarsal tubercle distinct, conical; (14) terminal phalanges are slightly rounded; (15) xiphisternum not large, shallow notch posteriorly; (16) male secondary sexual characteristics unknown; (17) eggs yellow (in alcohol).

COMPARISONS: Rana sinica superficially resembles other Asian cascade ranids, including Huia nasica , Rana andersonii , R. archotaphus , R. chalconota , R. chloronota , R. grahami , R. graminea , R. hainanensis , R. hejiangensis , R. hosii , R. jingdongensis , R. junlianensis , R. kwangwuensis , R. leporipes , R. livida , R. margaretae , R. schmackeri and R. tiannensis (table 12). Unlike the species listed above, R. sinica has a layer of skin overlying its tympanum and its terminal phalanges are slightly rounded (not T­ shaped; R. leporipes has oblong, somewhat rounded distal phalanges). The absence of a lip­stripe in R. sinica further differentiates it from H. nasica , R. archotaphus , R. chalconota , R. chloronota , R. grahami , R. graminea , R. hejiangensis , R. hosii , R. junlianensis , R. kwangwuensis , R. leporipes , and R. livida . Eggs of H. nasica , Rana andersonii , R. chalconota , R. grahami , R. junlianensis , R. margaretae , and R. schmackeri are white with melanic poles, whereas those of R. sinica are immaculate. The smooth green dorsum further distinguishes R. sinica from H. nasica , R. andersonii , R. jingdongensis , R. grahami , R. graminea , R. leporipes , R. schmackeri , and R. tiannensis . Huia nasica has an olive­ brown dorsum ( R. sinica green). Rana hainanensis further differs from R. sinica in its size (mean female SVL R. hainanensis 103 mm) and relative lengths of fingers (II <IV <I for R. hainanensis , I <II <IV for R. sinica ). Rana andersonii has a rough, olivebrown dorsum. Rana hejiangensis has smaller males (SVL 47 mm) and a different finger formula (II <I <III) than R. sinica . Rana julianensis and R. kwangwuensis differ from R. sinica in their relative finger formula (II <I <IV). Rana jingdongensis possesses vertical lip bands, large toe disks, and is fully webbed to all disks. Rana graminea differs from R. sinica in that its nares is closer to the tip of the snout than to the eye (halfway in R. sinica ), and it has a different finger formula (II = I <IV for R. graminea ). Rana margaretae further differs from R. sinica in having larger females (SVL 78–88 mm). Rana grahami has pustules on the dorsum and flanks and no digital disks (only slightly swollen tips). Rana schmackeri has a smooth, heavily spotted dorsum. Rana tiannensis has a rough, brown dorsum with large, prominent lateral granulations. Rana chalconota differs from R. sinica by having distinct dorsolateral folds, a pointed snout (vs. rounded), and an outer metatarsal tubercle. In R. archotaphus the outer metatarsal tubercle is present. Rana hosii differs from R. sinica by its dorsolateral folds and feeble tarsal folds (absent in R. sinica ). Rana chloronota differs from R. sinica in being larger (SVL for adult females 80–100 mm for R. chloronota ), having nostrils closer to the tip of the snout than the eye (halfway for R. sinica ), and a different digital formula (II <I <IV <III for R. chloronota ). Rana leporipes also differs from R. sinica by having a white supratympanic fold (not colored in R. sinica ). Rana livida has a solid­colored dorsum with white spots on its sides (flanks a different color for R. sinica , lacking spots), and it lacks transverse bands on the arms and legs (present in R. sinica ).

DESCRIPTION OF HOLOTYPE: HDL greater than HDW (132%), HDW 26% of SVL, HDL 34% of SVL; snout short, rounded in dorsal view; protruding beyond margin of lower jaw, rounded in lateral view, EYE prominent, smaller than SNT, IOD broader than EYE and upper eyelid. Top of head flat; canthus rostralis rounded; loreal region steeply concave; nostril about one­half the distance from eye to tip of snout; supratympanic fold weak; tympanum round, indistinct, covered by layer of skin; TMP 52% of EYE in females. Choanae ovoid; vomerine dentigerous processes prominent, oblique, posteromedial to choanae, each bearing numerous teeth. Tongue cordiform, distinctly notched posteriorly, free for part of its posterior length.

Forearm robust; relative lengths of fingers I <II <IV, III <snout; ventromedial callous pad on III almost to proximal tubercle; disks slightly expanded (<2× base of phalanges); circummarginal grooves present ventrally; terminal phalanges rounded; subarticular tubercles conical. Hindlimbs moderately robust; extend 15 mm beyond snout when adpressed; TIB 59% of SVL; FTL 30% of SVL; toe II is longer than all others, III = IV; inner tarsal fold absent; feet fully webbed to base of toe disk on II, III, and IV, I and V without external fringes; toes long, slender, with slight, rounded disks; ventral circummarginal grooves present; subarticular tubercles prominent, conical; inner metatarsal tubercle ovoid, long; outer metatarsal tubercle absent.

Xiphisternum small, with a shallow notch posteriorly.

Skin on dorsum smooth, flanks with slight granulations; dorsolateral fold absent; small tubercles posteroventral to tympanum; granules on thighs and around cloaca; cloacal opening unmodified, directed posteriorly, at upper level of thighs.

COLOR IN LIFE (in preservative): Dorsum green (bronze­green to brown), flanks gray (blue­gray to light brown); loreal region black (dark blackish brown), lip­stripe absent; dorsal limbs and digits brown with dark brown transverse bands; posterior surface of thighs black with white marbling; venter creamy white; ventral side of limbs creamy yellow; webbing marbled white on dark brown (brown).

SECONDARY SEXUAL CHARACTERS: The female holotype has large, immaculate yellow eggs (possibly white in life).

MEASUREMENTS OF HOLOTYPE (in mm): SVL 66.6; HDL 22.5; HDW 17.6; EYE 8.2; IOD 13.4; TMP 4.2; TIB 39.4; femur 33.7; FTL 33.7.

REMARKS: The holotype is the only known specimen of R. sinica ; all others are lost. This redescription is based on the original description by Ahl (1925) with amendments and additions based on our examination of the holotype. Ahl described the holotype as a male, but it is clearly a gravid female. As well, Ahl described a frog with large finger and toe pads. Although the condition of the specimen did not allow for accurate pad measurements to be made, the enlarged pads on the holotype are not as large as those on other species in the Rana chloronota complex. This species differs significantly from the other members of the Rana chloronota complex in preservative, but presumably has superficial resemblances in life. Ahl (1925) believed that R. sinica was closely related to Staurois natator .

Figures

Fig. 10. Holotype of Rana sinica (ZMB 9785), dorsal view (left), ventral view (right). Scale equals 5 mm.