Fejervarya cancrivora (Gravenhorst, 1829)

Yodthong, Siriporn, Stuart, Bryan L. & Aowphol, Anchalee, 2019, Species delimitation of crab-eating frogs (Fejervarya cancrivora complex) clarifies taxonomy and geographic distributions in mainland Southeast Asia, ZooKeys 883, pp. 119-153 : 119

Fejervarya cancrivora (Gravenhorst, 1829)

Rana cancrivora Gravenhorst, 1829: 41; Dubois and Ohler 2000: 30; Sumida et al. 2002: 294

Rana cancrivora raja Smith, 1930: 96

Rana raja Taylor, 1962: 373; Stuart et al. 2006: 19

Fejervarya cancrivora : Dubois & Ohler, 2000: 35; Kurniawan et al. 2014: 1

Fejervarya cancrivora : Large type Kurniawan et al. 2010: 222; Kurniawan et al. 2011: 12

Fejervarya raja : Chan-ard 2003: 110; Chuaynkern and Chuaynkern 2012: 169

Diagnosis.

Fejervarya cancrivora can be characterized by the following combination of characters: (1) large size, SVL 60.2-79.8 mm in males, 85.1-107.1 mm in females (Table 4 ; Appendix 2, 3); (2) head length slightly greater than head width; (3) skin on dorsum and flank with spinules and glandular warts, with irregular skin folds not arranged in series; (4) relative finger lengths II <IV <I <III; (5) dermal fringe on Finger II and III; (6) prepollax indistinct; (7) palmar tubercles indistinct; (8) foot moderately webbed with webbing formula I1 –11/2II1–2III1–2IV2– 1V; (9) dermal flap on postaxial side of Toe V; (10) Fejervaryan lines absent; (11) inner metatarsal tubercles prominent; (12) inner tarsal ridge prominent on distal half to two-thirds of tarsus, and (13) vocal sacs in adult males with wrinkled skin covered by triangular, very dark brown blotches on each side of throat.

Description of neotype.

Dubios and Ohler (2000) designated and described the neotype adult male, FMNH 256688, from Java, Indonesia ( Fig. 4 A–B ; Table 1 ). We supplement their description of the neotype, as follows: rather large size, body rather slender; head narrow, slightly longer than wide; snout oval in dorsal view, round in lateral view, projecting beyond lower jaw; nostril dorsolateral, pointed oval, with small lateral flap, closer to tip of snout than eye; canthus indistinct, rounded; loreal region concave and obtuse; eye diameter about 60% snout length; interorbital space flat, less than width of upper eyelid and internarial distance; pineal body visible; tympanum distinct, rounded [oval according to Dubois and Ohler (2000)], about 90% of eye diameter, not depressed relative to skin of temporal region, tympanic rim weakly elevated relative to tympanum, dorsoposterior margin obscured by supratympanic fold; two vomerine ridges bearing a few small teeth between choanae, obliquely oriented at an angle of 45° to body axis, closer to choanae than to each other; tongue large, cordate, emarginate [based on Ohler and Dubois (2000), not examined by us]; distinct supratympanic fold extending from eye to axilla, not obscuring dorsoposterior margin of tympanum.

Forelimbs short, rather stout [rather thin according to Dubois and Ohler (2000)], slightly longer than hand; fingers rather long, thin; tip of fingers slightly rounded and swollen [pointed according to Dubois and Ohler (2000)], but not expanded into discs; relative length of fingers II <IV <I <III; fingers II and III with dermal fringe; webbing on fingers absent; subarticular tubercles prominent, rounded; supernumerary tubercles absent; prepollex indistinct, oval; palmar tubercles indistinct.

Hindlimbs moderately short, robust; tibia longer than thigh, but shorter than distance from base of inner metatarsal tubercle to tip of Toe IV; toes long, thin; tips of toes rounded [pointed according to Dubois and Ohler (2000)], not expanded into discs; relative length of toes I <II <V <III <IV; webbing moderate, deeply excised between toes, formula I1-11/2 II1 –1III1–2IV2– 1V, Toe I webbed to base of distal phalanx; preaxial side of Toe II webbed to point between distal subarticular tubercle and distal phalanx, continuing as narrow fringe to base of distal phalanx; postaxial side of Toe II webbed to base of distal phalanx; preaxial side of Toe III webbed to distal subarticular tubercle, continuing as narrow fringe to base of distal phalanx, postaxial side of Toe III webbed to base of distal phalanx; preaxial side of Toe IV wedded to distal subarticular tubercle, continuing as narrow fringe to base of distal phalanx, postaxial side of Toe IV webbed to distal subarticular tubercle, continuing as narrow fringe to base of distal phalanx, Toe V webbed to base of distal phalanx; dermal flap well developed, extending along postaxial side of Toe V from level of inner metatarsal tubercles to distal phalanx; subarticular tubercles prominent; inner metatarsal tubercle prominent, oval, less than length of Toe I; distinct dermal ridge extending along inner metatarsal tubercle to distal phalanx of Toe I; distinct inner tarsal ridge on distal two-third of tarsus ( Fig. 5A ); outer metatarsal tubercles absent; supernumerary tubercles absent; tarsal tubercle absent.

Skin on snout and interorbital region shagreen; skin on eyelid with glandular warts and spinules; skin on dorsum with irregular skin folds, with intervening glandular warts and spinules; dorsolateral fold extending posteriorly to two-thirds length of dorsum; skin on side of head with small spinules; skin on flank with glandular warts; skin on cloacal region with dense glandular warts; skin on forelimbs, thigh, tibia and tarsus with glandular warts and spinules; skin on ventral surfaces smooth, except dense, fine spinules on chin. Nuptial pad with small translucent spinules on dorsal and medial surface of Finger I from base of distal phalanx to slightly over the base of prepollax; vocal sac present on both sides of throat, with wrinkled skin covered by triangular dark brown blotches. Fejervaryan lines absent.

Coloration of neotype in preservative.

Dorsum and side of head medium brown with indistinct dark brown markings; dark brown band between outer margins of upper eyelids; tympanum brown with inferior half more translucent, lighter in coloration than head; flank creamy white with dark brown marbling; three wide dark brown vertical spots on upper lips; wide light brown mid-dorsal stripe continuous from tip of snout to vent; dorsal surfaces of forelimbs, thigh, tibia, and foot brown with dark brown transverse spots; posterior surface of thighs with irregular pattern of dark brown marbling on white background; chin mottled dark brown, throat with triangular dark brown blotches on each side; chest, belly and ventral surfaces of hindlimbs creamy white with indistinct dark brown mottling; ventral surfaces of forelimbs creamy white; ventral surfaces of hand and foot brown; lower lip creamy white with dark brown spots.

Coloration of referred Thai specimen in life.

Adult male ZMKU AM 01426 ( Fig. 6 A–E ) from Khuan Khanun District, Phatthalung Province, Thailand. SVL 60.3 mm. Dorsum dark brown with indistinct darker markings, side of head lighter brown; dark brown band between outer margins of upper eyelids; lower half of tympanum with brown blotches; dark brown streak on canthus rostralis from tip of snout to eye; dark brown streak from eye along supratympanic fold to posterior rim of tympanum; flank creamy white with dark brown marbling; three wide dark brown spots on upper lips; a wide beige mid-dorsal stripe continuous from tip of snout to vent; dorsal surfaces of forelimb, thigh, tibia, and foot dark brown with darker transverse spots; posterior part of thigh with irregular pattern of dark brown marbling on light brown background; chin and chest creamy white with dark brown mottling; throat with triangular dark brown blotches on each side; ventral surfaces of forelimbs and belly creamy white; ventral surfaces of hindlimbs creamy white with dark brown mottling; ventral surfaces of hand and foot brown; lower lip creamy white with dark brown spots.

Variations.

Females are distinctly larger in size (Table 4 ; Appendix 3), lack nuptial pads and vocal sacs, and have fewer spinules and glandular warts on dorsum and flanks than males. Two male specimens (ZMKU AM 01511 from Nakhon Si Thammarat Province, Thailand and CNHM 131100 from Java, Indonesia) have nuptial pads extending to the base of prepollax. Most male specimens have dense fine spinules over the entire surface of the chest, belly, and ventrolateral surface.

The examined male and female specimens closely resemble the neotype in morphology, with most observed variation pertaining to coloration. Dorsal coloration in preservative varied from medium to very dark brown with darker markings. Markings or spots on dorsum, and transverse spots on dorsal surface of forelimbs and hindlimbs fainter than neotype in some individuals. Flank pale brown with dark brown marbling in some individuals. Ventral coloration pale brown in some individuals, with dark mottling on chin and chest. Ventral surface of hand pale brown or creamy white in some individuals. Dorsal vertebral stripe present (n = 18, 41%) or absent (n = 26, 59%). Two specimens from Nakhon Si Thammarat Province, Thailand (ZMKU AM 01509 and ZMKU AM 01513), have a narrow light brown stripe on tibia. Pineal body not visible in one male specimen from Pattani Province, Thailand (THNHM 21248).

Distribution.

Based on a combination of the morphological and genetic studies of F. cancrivora large type ( Kurniawan et al. 2010; 2011; 2014), the reported distribution of F. raja (Chan-ard 2013; Chuaynkern, and Chuaynkern 2012), and localities of specimens examined in this study, F. cancrivora is distributed from south of the Isthmus of Kra in Thailand, West Malaysia, Kalimantan (Borneo), Sumatra, West and Central Java, and Bali in Indonesia, with introduced populations in Papua New Guinea and Guam ( Christy et al. 2007; Frost, 2019). In Thailand, F. cancrivora was confirmed to occur at Phatthalung, Nakhon Si Thammarat, Pattani, Songkhla, and Narathiwat Province ( Fig. 1 ; Table 1 ).

Habitat, ecology and natural history.

Specimens were collected in Thailand (Khuan Khanun District, Phatthalung Province and Pak Panang District, Nakhon Si Thammarat Province) at night (1900-2200 h) following light rain during May and October 2016. At Khuan Khanun, frogs were sampled in grasslands, rice paddy fields near standing or slow flowing ditches, and ponds at 1-24 m elevation ( Fig. 7A ). These were found sitting on the ground near water bodies, or hiding within grass or in mud cracks in the ground, and jumped to water bodies when disturbed. Other anuran species found in syntopy at this locality included Duttaphrynus melanostictus (Schneider, 1799), F. limnocharis , Hoplobatrachus rugulosus (Wiegmann, 1834), Hylarana erythraea (Schlegel, 1837), Polypedates leucomystax (Gravenhorst, 1829) and Microhyla butleri Boulenger, 1900. At Pak Phanang District, frogs were collected at night (1900-2100 h) after heavy rain in November 2017. These were found on the bank or in the water of brackish shrimp ponds near the Pak Phanang River at 0 m asl ( Fig. 7B ). No other anuran species were found in syntopy at this locality, although F. moodiei was sampled at a site approximately 4.5 air-km, or 5.2 km following the river course, upriver (below).

Figures

Figure 1. Map of sampling localities of the Fejervarya cancrivora complex, including F. cancrivora neotype (yellow pentagon), F. cancrivora sensu stricto (yellow circles), F. moodiei holotype (blue diamond), F. moodiei (blue triangles), and F. cancrivora samples that were referred to F. raja (red circles) prior to this study. Open symbols indicate molecular data only, shaded symbols indicate morphological data only, and shaded symbols with center dots indicate both molecular and morphological data were studied.

Figure 4. Adult male neotype of Fejervarya cancrivora (FMNH 256688) in preservative in A dorsal and B ventral views.

Figure 5. Plantar and metatarsal views of A adult male neotype of Fejervarya cancrivora (FMNH 256688) B adult male F. cancrivora (ZMKU AM 01426) from Khuan Khanun District, Phatthalung Province, Thailand C adult female holotype of F. moodiei holotype (CM 3724), and D adult male F. moodiei (ZMKU AM 10390) from Mueang Phang-nga District, Phang-nga Province, Thailand. The inner metatarsal ridge on the tarsus of F. cancrivora is indicated with an arrow.

Figure 6. Adult male Fejervarya cancrivora (ZMKU AM 01426) from Khuan Khanun District, Phatthalung Province, Thailand (SVL = 66. 9 mm) immediately prior to preservation in A right lateral B dorsal C ventral D right palmar, and E right plantar views. Photographs by Attapol Rujirawan.

Figure 7. Exemplar habitats in Thailand of A Fejervarya cancrivora at a wetland in Khuan Khanun District, Patthalung Province B F. cancrivora at a brackish shrimp pond near Pak Phanang river, Pak Phanang District, Nakhon Si Thammarat Province C F. moodiei at mangrove forest in Thai Mueang Distrinct, Phang-nga Province, and D F. moodiei at brackish fish ponds near mangroves at the mouth of the Prasae River, Kleang District, Rayong Province. Photograph A by Attapol Rujirawan.