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Frogs of Borneo

Frogs of Borneo

Frogs of Borneo

Frogs of Borneo

Frogs of Borneo

Frogs of Borneo

Frogs of Borneo

Frogs of Borneo

Frogs of Borneo

Frogs of Borneo

Frogs of Borneo

Limnonectes finchi

Limnonectes finchi tadpoles have been observed in shallow muddy forest pools, pig wallows, and muddy stagnant sections of small forest streams. The tadpoles are benthic and remain close to the bottom while foraging. Their diet has not been analyzed in detail, but they likely feed opportunistically on small items of organic matter, such as algae, decaying plant material, and microscopic organisms.
  • Family:
    Dicroglossidae
  • Genus:
    Limnonectes
  • Ecomorph:
    benthic, exotrophic, lentic
  • Waterbody Type:
    stagnant
  • Water Column:
    bottom
  • Feeding Type:
    feeding, generalist
  • Size:
    25 mm
  • Development:
    larva, tadpole
  • Adult:
    Limnonectes

Coloration

Mostly brown to olive brown dorsally. Head and trunk lack a well-defined pattern, showing diffuse darker and lighter areas dotted with scattered black melanocytes. In lateral view, the lower face of the head and lower flanks may have irregular dark markings. Horizontal dashes of silver iridocytes are abundant over this background. Ventral skin transparent, with few scattered iridocytes; gills and gut coil visible. Body color continues onto the dorsal tail. Clusters of well-defined black dots form irregular flecks along the sides of the tail, including the fins, less so in the proximal lower fin; pattern may be accentuated in posterior third of tail. Vermiculate melanocytes are visible at high magnification, particularly in the proximal upper fin. Tail and tail fins also bear scattered clusters of pale, shiny iridocytes.

Snout

Smoothly triangular in dorsal view, with a small protruding, slightly truncated part medially. Snout moderately long, tapering to a narrowly rounded tip in lateral view. Oral disc may project laterally from under the snout in dorsal view.

Oral Disc

Small (about one fourth of head width or less), ventral, reaching but not projecting beyond snout contour in dorsal view. Clear emargination separates upper and lower lips. Blunt papillae along margins, with a broad medial gap in the upper lip and a narrow medial gap in the lower lip. Marginal papillae relatively thick and low in number, arranged in a staggered single row on lower lip, giving appearance of a double row. Submarginal papillae absent. LTRF 2(2)/3(1). Beaks moderately strong, well keratinized but thin; edges bear fine serrations. Upper beak almost straight medially, arched laterally; lower jaw sheath wide V-shaped.

Body

Small to medium-sized. Dorsal view shows oval contour. Head as wide as trunk. Widest point at gill region. Head smoothly triangular in dorsal view. Body dorsoventrally depressed. Spiracle sinistral, opening posteriorly. Medial rim of spiracular orifice attached to body wall. Spiracular orifice below mid-body level in lateral view. Lateral line organs indistinct.

Eyes & Nostrils

Eyes dorsolateral. Nostril closer to snout than eye, oriented anterolaterally, moderately sized with smooth rim. Iris dotted with brass-to-gold iridocytes forming a solid ring around pupil, less dense anteriorly and posteriorly; in some individuals narrow areas lacking iridocytes form vertical black streaks.

Tail

Approximately 67% of total length. Muscular part strong, almost as high as trunk in lateral view; half of maximum trunk width in dorsal view. Upper fin originates at ~20% of tail length, higher and more convex than lower fin, arching relatively shallow. Upper fin starts flat then abruptly rises. In posterior fifth, fins converge into a narrowly rounded tip with slight concavity, producing a weakly cuspidate tail tip. Maximum tail height at mid-tail or slightly posterior. Lateral tail vein and myosepta indistinct.

Similar Species

Limnonectes finchi tadpoles are distinguished from many other Bornean tadpoles by LTRF 2(2)/3(1). Features such as body shape, relatively small oral disc, low keratodont row count, and benthic habits are shared with other Limnonectes species. The bodies of L. finchi and L. palavanensis appear more dorsoventrally depressed than those of Creek Frog tadpoles ("L. kuhlii" complex), which also have a more bluntly rounded, less tapering snout in lateral view. L. ingeri, L. leporinus, L. malesianus, and L. paramacrodon are excluded by their respective LTRF (only one upper lip keratodont row). L. finchi and L. palavanensis stand out among Limnonectes by tail fin contour and relatively low fins.

Literature

The male calls to attract the female to a suitable nest site. The egg clutch is laid on land, under leaf litter. The male guards the clutch. When the tadpoles hatch from the eggs, they climb the back of the male, which then carries the tadpoles to the nearest suitable body of water, where the tadpoles disperse and develop independently.
Inger, R.F. (1985) Tadpoles of the forested regions of Borneo. Fieldiana Zoology new series. 26:1–89.