Leptodactylus podicipinus (Cope 1862)

The pointedbelly frog, Leptodactylus podicipinus, is a medium-sized South American leptodactylid frog, brownish in color dorsally, with a darker underside speckled with white spots. Females range in snout-vent length between 30-54 mm whereas males are smaller, 24-43 mm.Tadpoles grow to 28 mm long, and have dark brown coloration, sometimes with white tail flecks (Heyer et al. 2004; Heyer 1994).

Part of the 13-species L. podicipinus-wagneri species complex in the L. melanotus group, L. podicipinus is widely distributed with the most southern distribution of the species in this group.L. podicipinus is known from open formations of Paraguay, Northern Uruguay, Northern Argentina and Bolivia.It also inhabits the Amazon basin of central Brazil, but only along the river Madiera to the river Amazonas, and east along the river Amazonas; Heyer suggests that this distribution indicates a recent invasion of the species to Amazonia.Heyer (1994) also reported a distinct isolated population in Igarapé Belém, Amazonas, Brazil (although his map indicates that perhaps this population is in western Brazil, on the Amazonas river near the border of Columbia and Peru), but he rejects this as a true locality for this species, suggesting instead that the frogs collected here were confused with collections from another site (Heyer et al. 2004; Heyer 1994).

Pointedbelly frogs live only in open habitats - grasslands and disturbed areas at altitudes up to 550 m (3800 feet) asl and are adaptable to urban areas. Adult frogs are nocturnal, sit and wait generalist predators that eat a wide range of prey (Rodrigues et al. 2004).Males create small protective basins on the edge of temporary or permanent ponds, a strategy thought effective against aquatic predators. These basins fill with water from the adjacent water source and protected by a roof of leaves and brush above their hole, the males then call from within.Females then lay pink eggs into a foam nest in the depression, and attend the eggs and tadpoles until metamorphosis.In later stages tadpoles migrate out into the quiet pond waters (Prado et al. 2002).

Diagnosis A medium size frog (females 30-54 mm SVL, males 24-43 mm snout vent length) with dorsolateral folds rarely long and never well developed; yellowish glandular patches on sides and groin; have small, distinct, light belly spots; ventral and posterior thigh patterns merge; posterior thighs are mottled with no indication of light stripes and have either narrow or just-swollen toe tips. Brownish above, belly dark gray scattered with white spots.

In open formations of Paraguay, adjacent Argentina, Bolivia, north of Uruguay, central Brazil, and extending along the Rio Madiera and Rio Amazonas within the Amazon basin, with a problematical outliner from Igarapé Belém, Amazonas, Brasil; with a known altitudinal range up to 550 m.

Adult morphology A medium size frog, males smaller than females. Head ogival, slightly larger than wide. Snout rounded, the upper jaw slightly projecting beyond the lower. Somewhat protruding nose; nostrils superolateral, very close to the tip of snout. Internarinal interval equal to the interocular distance, which is subequal to the width of upper eyelid. Canthus rostralis rounded; loreal region slightly concave, ineeting with a very obtuse angle the upper lip. Eyes prominent, laterally located. Maxillar teeth developed; vomerine teeth in two heavy patches between and behind the choanae. Tongue cordifom, notched posteriorly. Tympanum round, distinct, more than 2/3 of the eye diameter. A moderate tympanic fold, reaching the axilla. Fingers free bur distinctly fringed. Rate of the finger lengths: IV-II-I-III. Metacarpal and subarticular tubercles moderate: a crescentic pad at the base of thumb. Two acuminate black horny spines on the first finger of males. Toes webbed at the base and widely fringed. Metatarsal tubercles moderate and blunt; conical subarticular tubercles of toes prominent. Tarsal fold large and distinct. Skin pustular and warty, mostly on the back and hindlegs; yellowish ventro-lateral glandular patches and larger glands on the posterior region of the femur. Belly smooth; lower posterior surface of thighs coarsely granular. A male vocal sac present. Dorsally dark brown, with dilute spots: a triangular, light-edged dark interocular spot. Ventrally dark olive-brown, closelv scettared with round uncolored dots, also evident on the sides. Larval morphology The body is oval and slender wider in the region of the spiracle. The tail length is twice the length of the body, its high transparent fins ending in the acuminate tip. The anal tube is opening medially. The nostrils are located at about the same distance between eye and tip of snout, round and sloping. Dorsally is dark brown, with metallic blendings; ventrally light, Rows of the lateral line system are remarkably evident. The mouth, encircled by close papillae. The tooth rows formula is usually 2(1)/3.

LC. Least Concern.

Leptodactylus podicipinus (Cope, 1862)

Cystignathus podicipinus Cope, 1862:156 [type locality: Paraguay; holotype ANSP 14539, adult male].

Leptodactylus podicipinus.—Boulenger, 1882:248 [apparent first association of podicipinus with Leptodactylus].

Leptodactylus nattereri Lutz, 1926:1011 [type localities: Ilha Secca and Cachoeira do Maribonda, São Paulo, Brazil; unquestioned syntypes MN-AL 1015, 1016, plus unnumbered specimen in same jar with 1015, 1016].

DIAGNOSIS.—Leptodactylus podicipinus has the southernmost distribution of members of the podicipinus-wagneri complex but the range extends into Amazonia, central Brazil and extends toward northeast Brazil. Other Leptodactylus with toe fringes (other than L. ocellatus and its closest relatives) known to occur sympatrically with podicipinus or are from the same region as podicipinus are L. bolivianus, dantasi, diedrus, griseigularis, leptodactyloides, natalensis, petersii, pustulatus, and riveroi. Leptodactylus podicipinus is smaller than bolivianus or riveroi (podicipinus females 30–54 mm SVL, males 24–43 mm SVL; bolivianus females to 88 mm SVL, males to 94 mm SVL; riveroi females to 81 mm SVL, males to 63 mm SVL), and the dorsolateral folds are rarely long in podicipinus and never well developed, whereas all bolivianus and riveroi have a pair of long, well-developed dorsolateral folds. Although many L. podicipinus have small, distinct, light belly spots, not all do; dantasi has large, distinct, light belly spots and is larger than podicipinus (only known female dantasi 68 mm SVL). The bellies of L. podicipinus usually are extensively mottled and the ventral and posterior thigh patterns merge; the bellies of diedrus usually lack melanophores and the ventral and posterior thigh patterns abut. Leptodactylus podicipinus is smaller than griseigularis (griseigularis females 39–58 mm SVL, males 35–51 mm SVL), and the bellies of podicipinus are usually darker than those of griseigularis (griseigularis bellies usually lightly mottled and no individuals have distinct light belly spots). The posterior thighs of most podicipinus are mottled with no indication of light stripes; the commonest posterior thigh state in leptodactyloides is a distinct stripe, and no leptodactyloides have distinct light belly spots. All L. podicipinus have either narrow or just-swollen toe tips; just over half of all natalensis have toe tips larger than the just-swollen category, and no natalensis have distinct light belly spots. The most common toe-tip state in L. podicipinus is narrow; the most common toe-tip state in petersii is just swollen and some individuals have swollen and just-expanded toe tips. No petersii have distinct belly spots. No L. podicipinus have discrete, distinct light spots on the posterior face of the thigh; all pustulatus do.

ADULT CHARACTERISTICS (N = 532 females, 419 males).—Light posterior lip stripes rarely very distinct (2%), sometimes distinct (20%), usually indistinct (43%), often indiscernible (35%), when discernible, stripe extending from either under midportion of eye or posterior corner of eye; light posterior thigh stripes rarely distinct (4%), sometimes indistinct (17%), usually posterior thighs completely mottled with no indication of light stripes (79%); dorsolateral folds (apparently) sometimes absent (9%), usually short (44%) or moderate length (46%), rarely long (1%); toe tips usually narrow (75%) or just swollen (25%); male black thumb spines rarely small (3%), small-medium (2%), medium–large (3%), or large (2%), usually medium size (91%); chin/throat usually with distinct spots on a darker background (58%), distinct light spots often extending to cover belly (42%); belly rarely with a light scattering of melanophores (4%), sometimes with a moderate profusion of melanophores (20%), usually dark, extensively profused with melanophores (75%).

Females 29.5–54.3 mm SVL (x = 38.8 ± 3.8), males 24.5–43.3 mm SVL (x = 34.0 ± 3.1); female head length 30%–40% SVL (x = 35 ± 2%), male head length 31%–41% SVL (x = 36 ± 2%); female head width 30%–42% SVL (x = 33 ± 1%), male head width 29%–39% SVL (x = 34 ± 1%); female tympanum diameter 6%–9% SVL (x = 7 ± 0%), male tympanum diameter 6%–9% SVL (x = 8 ± 0%); female thigh length 32%–47% SVL (x = 39 ± 3%), male thigh length 31%–47% SVL (x = 41 ± 3%); female shank length 35%–46% SVL (x = 41 ± 2%), male shank length 36%–48% SVL (x = 42 ± 2%); female foot length 40%–59% SVL (x = 50 ± 3%), male foot length 43%–57% SVL (x = 52 ± 2%).

LARVAL CHARACTERISTICS.—Maximum total length stage 38, 28.2 mm; body length 34%–41% (x =38.2) total length; maximum tail depth 48%–56% (x = 51.4) body length; nostril just nearer eye than tip of snout or about midway between tip of snout and eye; intemarial distance just greater than or about equal to interorbital distance; eye diameter 9%–12% (x = 10.8) body length; mouth subterminal; oral disk entire; spiracle sinistral; anal tube median; oral papilla formula 1–2; oral disk width 17%–21% (x = 19.2) body length; oral papilla gap 38%–57% (x = 44.4) oral disk width; labial tooth row formula 2(2)/3; number of labial teeth in a single split row of A-2, stages 37–38, 63–78; number of labial teeth in 0.1 mm measured in middle of one split tooth row in A-2, 6–7 (x = 6.3); tadpole essentially uniform brown with heavy suffusion of melanophores including oral disk, anal tube, and dorsal and ventral tail fins; tail either uniform brown or with very few, small light flecks.

The preceding larval description is based on samples from Curuçá, Amazonas, and Estancia Caiman near Miranda, Mato Grosso do Sul, Brazil. Vizotto (1967) described and figured larval L. podicipinus from the interior of the State of São Paulo, Brazil.

ADVERTISEMENT CALL.—Call rate 0.5–8.4 calls per s; call duration 0.02–0.04 s; calls with distinct initial pulses and rest of call pulsatile or entire call pulsatile, with 3–7 pulses/partial pulses; calls markedly frequency modulated with extremely sharp attacks and fast rise times, short terminal frequency downsweep present or absent; broadcast frequency range 1000–3500 Hz with greater intensity of call either in lower frequency range at beginning of call or higher frequency range at end of call; harmonics weakly to moderately developed (Figures 8, 13, 22, 23).

KARYOTYPE.—Diploid number 22, 3 pair median, 2 pair submedian, 2 pair subterminal, 4 pair terminal; secondary constriction in chromosome pair 8 (Bogart, 1974; specimens from São José do Rio Prêto, São Paulo, Brazil).

GEOGRAPHIC VARIATION.—Variation for L. podicipinus within Regions 3 and 4 already has been discussed (as the Dark Belly OTUs). Among regions, there is variation in expression of the light stripe on the posterior thighs. In Region 4, only 5% of the individuals show any indication of light stripes, whereas 30% of the individuals in Regions 1, 3, and 7 (combined) have at least indications of light stripes if not distinct light stripes. There is no obvious geographic variation in size (based on specimens ≤ or ≥ 2 standard deviations of the mean). Both large and small females occur in the large sample from Porto Velho, Rondônia, Brazil. It is worth noting that 13 of the 17 males and all 14 females ≥ 2 standard deviations from the mean occur in the single sample from Alejandria, Beni, Bolivia.

DISTRIBUTION.—Open formations of Paraguay, adjacent Argentina, Bolivia, central Brazil, and extending along the Rio Madeira and Rio Amazonas within the Amazon basin, with a problematical outlier (discussed later) from Igarapé Belém, Amazonas, Brazil, with a known altitudinal range up to 550 m (Figure 43, Igarapé Belém = circle; Appendix 2).

Leptodactylus podicipinus, sometimes known as the pointedbelly frog, is a species of frog in the family Leptodactylidae. It is found in northern Argentina, Paraguay, Uruguay, Bolivia, and Brazil.

Leptodactylus podicipinus live in grasslands and open habitats, often near ponds and flooded areas. They are common in suitable habitats. Eggs are laid in foam nests at the edges of permanent or temporary ponds and flooded areas.

Male Leptodactylus podicipinus grow to a snout–vent length of 24 and 43 mm (0.94 and 1.69 in) and females to 30 and 54 mm (1.2 and 2.1 in).