Leptodactylus knudseni Heyer 1972

Leptodactylus knudseni Heyer

MATERIAL.—USNM field 44780 (one specimen dissected, stage 39, SVL 18.9 mm). Collected from forest pond at Reserva Biologica Rio Trombetas, Pará, Brazil, 9 February 1979, by Ronald I. Crombie.

REFERENCE.—The larval external morphology is being described by Ronald I. Crombie (pers. comm.). The habitus is very similar to that of L. labyrinthicus or L. pentadactylus.

GENERAL

Leptodactylus knudseni Heyer, 1972

Leptodactylus knudseni, Heyer, 1972:3. [Type-locality: Limoncocha, Napo, Ecuador. Holotype: LACM 72117, juvenile female.]

DIAGNOSIS.—Specimens of L. knudseni have a distinctive pair of dorsolateral folds. Dorsolateral folds are also found in some or all individuals of fallax, flavopictus, labyrinthicus, pentadactylus, rhodomystax, rhodonotus, rugosus, and stenodema. No individual knudseni has a distinct light lip stripe; all flavopictus and rhodomystax individuals do have distinct upper lip stripes. Most rugosus lack dorsolateral folds; when the folds are present, they are interrupted, contrasting with the continuous folds of knudseni. Leptodactylus knudseni is a large species (minimum adult SVL 97 mm) with a single thumb spine in the male; rhodonotus is a moderate-sized species (maximum adult SVL 90 mm) with two thumb spines per hand in males; stenodema is a moderate-sized species (maximum adult SVL 100 mm) in which the males lack thumb spines. The dorsolateral folds of knudseni do not extend past the sacrum, those of stenodema extend to the groin. Leptodactylus knudseni most closely resembles fallax, pentadactylus, and labyrinthicus within the pentadactylus group. No fold is present in knudseni from above the tympanum to the side of the body; such a fold occurs in pentadactylus, its entire length usually darkly outlined. The dorsolateral folds of pentadactylus extend to the groin. The hind limbs of knudseni are shorter (tibia of male 43±2 percent SVL, female 41±2 percent SVL, foot of male 45±3 percent SVL, female 43±2 percent SVL) than those of fallax (tibia of male 50±2 percent SVL, female 51±2 percent SVL, foot of male 51±4 percent SVL, female 53±1 percent SVL). Many labyrinthicus have light vertical bars on the upper lip; knudseni lack light vertical lip bars. The dorsolateral folds of labyrinthicus are often interrupted; those of knudseni are continuous. Leptodactylus knudseni is a smaller species (maximum SVL 170 mm) than labyrinthicus (maximum SVL almost 200 mm).

ADULT CHARACTERISTICS (N=61).—Dorsum usually barred, sometimes spotted or uniform (Figure 1, A–D, G, H. L); lip uniform or with dark triangular bars (Figure 2, A–E); posterior surface of thigh variously mottled, spotted, or uniform (Figure 3, A–G, I, J, R); upper tibia distinctly or indistinctly barred (Figure 4, A, C, E) or rarely lacking distinct pattern; a pair of usually dark outlined dorsolateral folds from eye to no more than sacrum, usually continuous, sometimes interrupted; dark outlined fold from eye over tympanum to shoulder; no distinct fold from above tympanum to side of body; male thumb with one spine per hand, a rudimentary second spine rarely developed; male chest spines present or absent, present in all specimens 140 mm SVL or larger; upper tibial and distal tarsal surfaces smooth or with scattered to many white or black-tipped tubercles; soles of foot usually smooth, rarely with scattered white-or black-tipped tubercles; female SVL 132.0±8.9 mm, maximum 147.8 mm, male 127.4±2.1 mm, maximum 165.5 mm, female interorbital distance/head length ratio 0.18±0.02, male 0.18±0.01; female eye-nostril distance/head length ratio 0.25±0.01, male 0.26±0.01; female head length/SVL ratio 0.35±0.01, male 0.36±0.02; female head width/SVL ratio 0.37±0.01, male 0.38±0.02; female femur/SVL ratio 0.39±0.03, male 0.41±0.03; female tibia/SVL ratio 0.41±0.02, male 0.43±0.02; female foot/SVL ratio 0.43±0.02, male 0.45±0.03.

DISTINCTIVE COLORS IN LIFE.—Juveniles from Ecuador with a yellowish green head; the dorsum with greenish yellow bands enclosing black-edged brownish green areas. Adult posterior surface of thigh dark with light orange markings; belly sometimes yellow spotted (R. W. McDiarmid color slide).

LARVAL CHARACTERISTICS.—Unknown.

MATING CALL.—Dominant frequency modulated between 350–750 Hz (Figure 8); no harmonic structure in call; 0.02 s pulse of lower frequency (below 500 Hz) immediately followed by 0.1 s complexly pulsed call of higher frequency (above 500 Hz) (Figure 9).

KARYOTYPE.—Diploid number 22, 3 pair median, 4 pair submedian, 4 pair subterminal; no secondary constrictions (Heyer, 1972).

DISTRIBUTION (Figure 10)—The species occurs through the greater Amazon Basin.

BOLIVIA. BENI: Rurrenabaque (UMMZ 108594–96).

BRAZIL. AMAZONAS: Barreira do Matupiri (USNM 202518); Cachoeirinha (MZUSP field 752040), (USNM 202517); Novo Aripuanā (MZUSP field 752046–47); Tefé (MCZ 1294–95). PARĀ: Alegre, 15 km NE Marapanim (MZUSP 24997, 25949); Rio Mapuera, at Equator (AMNH 46180(2), 49484). RONDÔNIA: Alto Rio Machado (MZUSP 15907); Calama (USNM 202516); Forte Príncipe da Beira (MZUSP 25169); Pôrto Velho (MZUSP 16658–68, 16670–84).

COLOMBIA. AMAZONAS: Río Apaporis (USNM 144847). META: Menegua, E. Puerto López (USNM 147272). VAUPÉS: Timbó (UTA 3836, 5230–31).

ECUADOR. MORONA-SANTIAGO: Sucúa, 2 mi E of, on trail from Sucúa to Río Upano, 2700’ (USNM 196722). NAPO: Limoncocha (KU 99041, 122578, LACM 72117–49); Santa Cecilia (KU 104716, 104719, 111406–07, 122576, MCZ 57947, 57953, 57957–58). PASTAZA: Río Conambo (USNM 196723); Río Pucayacu (USNM 196726); Alto Río Pucayacu, Río Bobonaza (USNM 196724 (4); mouth of Río Shyona in Conambo R (USNM 196725).

FRENCH GUIANA. Maripasoula (MCZ 44560.)

GUYANA. Arakaka (UMMZ 66782); Demerara (AMNH 39636); Issano (UMMZ 83586–88); Kamakusa (AMNH 21406); Kartabo (AMNH 10424, 13488, 70881, CM 4064 5442); Kurupung, Upper Mazaruni Dist. (UMMZ 83589–92); Marudi (AMNH 49264); Rupununi, N of Acarahy Mts, W of New R (KU 69681–84); Shudi-kar-wau (AMNH 70117).

PERU. AYACUCHO: La Mar, Sivia on Apurimac R (FMNH 39719). Cuzco: Río Apurimac, Luisiana (AMNH 70389).

HUANUCO: Hacienda Pampayacu (MCZ 22821–22); Tingo Maria (USNM 193879–84). JUNIN: Tarma, valley of Vitoc R 900 m (FMNH 36831). LORETO: Pampa Hermosa (AMNH 42752). PASCO: Tsioventeni, Prov. Oxapampa (USNM 205553).

SURINAM. Godo Drai, TCWC 23563; Kaiserberg Airstrip, Zuid R (FMNH 128786–89).

TRINIDAD. No specific locality (MCZ 8663).

VENEZUELA. AMAZONAS: Capibara, 106 km SW Esmeralda, Brazo Casiquiare, 130 m (USNM field 19504–05); Paso del Diablo (AMNH 23164); Río Mavaca, 108 km SSE Esmeralda, 140 m (USNM field 17739). BOLIVAR: 13 km S and 1 km E Puente Cuyuni, 140 m (KU 166495–97).

Leptodactylus knudseni, commonly called Knudsen's frog is a species of frog in the family Leptodactylidae. Its local name is sapo-toro amazonico ("Amazonian toad-frog").

It is found in Bolivia, Brazil, Colombia, Ecuador, French Guiana, Guyana, Peru, Suriname, Venezuela, and possibly Trinidad and Tobago. Its natural habitats are subtropical or tropical moist lowland forests, moist savanna, rivers, intermittent rivers, intermittent freshwater marshes, and rural gardens. It is not considered threatened by the IUCN.