Leptodactylus petersii (Steindachner 1864)

Leptodactylus petersii (Steindachner, 1864)

Platymantis petersii Steindachner, 1864:254, plate 16: figs. 2, 2a–c [type locality: (Brazil; Amazonas) Marabitanas; holotype lost, originally in NMW collection].—Boulenger, 1882:247 [apparent first association of petersii with the genus Leptodactylus, as a synonym of Leptodactylus caliginosus].

Leptodactylus brevipes Cope, 1887:51 [type locality: Chapada, Brazil (= Chapada dos Guimaräes, Mato Grosso, Brazil); holotype ANSP 11270, female (?)].

Leptodactylus intermedius Lutz, 1930:8, plate 3: fig. 6 [type locality: Manacapuri (= Manacapurú) perto do Manaos (Amazonas, Brazil); syntypes MN-AL 1438–1441].

Leptodactylus podicipinus petersii.—Gorham, 1966:136 [apparent first proposal of petersii as a subspecies of podicipinus].

DIAGNOSIS.—Leptodactylus petersii occurs in greater Amazonia and the Guiana shield region. The other Leptodactylus species with toe fringes (except L. ocellatus and its closest relatives) that are known to occur sympatrically with petersii or that are from the same region are L. bolivianus, dantasi, diedrus, griseigularis, leptodactyloides, pallidirostris, pascoensis, podicipinus, riveroi, sabanensis, and wagneri. Leptodactylus petersii is smaller than bolivianus and riveroi (petersii females 31–51 mm SVL, males 27–41 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 petersii individuals have at most a pair of medium-length, moderately developed dorsolateral folds whereas all bolivianus and riveroi have a pair of long, well-developed dorsolateral folds. Leptodactylus petersii does not have distinct light spots on a dark belly; dantasi does. The belly of L. petersii usually is extensively mottled, whereas the belly of diedrus usually lacks melanophores. In addition, the ventral and posterior thigh patterns merge in L. petersii, whereas they abut in diedrus. Leptodactylus petersii, is smaller than griseigularis (griseigularis females 39–58 mm SVL, males 35–51 mm SVL), and the commonest belly pattern in petersii is an extensive mottle in an anastomotic pattern, whereas the commonest belly pattern in griseigularis is a light mottle that is not developed into an anastomotic pattern. Leptodactylus petersii individuals have relatively uniformly and extensively patterned bellies, often in an anastomotic pattern; leptodactyloides have more intense belly patterns anteriorly, and most individuals have moderate mottling but not in an anastomotic pattern; pallidirostris usually have lightly mottled bellies with a pattern ranging from a fine mottle to distinct, rather dark blotches, with the pattern usually more intense anteriorly. Almost no L. petersii have distinct light posterior thigh stripes; most leptodactyloides do. Leptodactylus petersii is smaller than pascoensis (pascoensis females 52–67 mm SVL, males 60–61 mm SVL), and the belly is usually darker in petersii than in pascoensis (pascoensis bellies never extensively mottled nor in an anastomotic pattern). No L. petersii have distinct light spots on the belly, whereas podicipinus commonly does. The commonest toe-tip state in L. petersii is just swollen, and some individuals have swollen and just-expanded toe tips; the commonest toe-tip state in podicipinus is narrow, and no podicipinus have swollen or just-expanded toe tips. Leptodactylus petersii is smaller than sabanensis (sabanensis females 42–57 mm SVL, males 35–46 mm SVL). Most L. petersii (56%) have light chin/throat spots; few sabanensis (15%) have light chin/throat spots, and no sabanensis have anastomotic or speckled belly patterns. Leptodactylus petersii is smaller than wagneri (wagneri females 52–82 mm SVL, males 39–61 mm SVL), and no petersii have long dorsolateral folds, whereas most wagneri do.

ADULT CHARACTERISTICS (N = 121 females, 197 males).—Light posterior lip stripes rarely very distinct (1%), sometimes distinct (12%), usually indistinct (44%) or not discernible (43%), when discernible, stripes extending from posterior corner of eye; light posterior thigh stripes rarely distinct (2%), occasionally indistinct (8%), usually absent (90%); dorsolateral folds sometimes (apparently) absent (10%), usually short (70%), sometimes moderate length (20%); toe tips narrow (14%), just swollen (62%), swollen (13%), or just expanded (11%); male black thumb spines small (16%), small-medium (15%), medium (64%), rarely medium-large (2%) or large (2%); chin/throat usually with light spots on a darker background (56%); belly rarely lightly mottled (4%), often moderately mottled (30%), usually extensively mottled (66%).

Females 31.2–51.3 mm SVL (x = 39.1 ± 3.9), males 26.6–41.1 mm SVL (x = 32.9 ± 2.6); female head length 35%–43% SVL (x = 39 ± 2%), male head length 36%–44% SVL (x = 40 ± 2%); female head width 32%–38% SVL (x = 35 ± 1%), male head width 33%–40% SVL (x = 36 ± 1%); female tympanum diameter 6%–10% SVL (x = 8 ± 1%), male tympanum diameter 8%–11% SVL (x = 10 ± 1%); female thigh length 36%–51% SVL (x = 43 ± 2%), male thigh length 36%–50% SVL (x = 43 ± 3%); female shank length 40%–50% SVL (x =44 ± 2%), male shank length 47%–49% SVL (x = 45 ± 2%); female foot length 47%–60% SVL (x = 53 ± 2%), male foot length 48%–60% SVL (x = 54 ± 2%).

LARVAL CHARACTERISTICS.—Maximum total length stage 36, 20.8 mm; body length 36%–44% (x = 40.3) total length; maximum tail depth 39%–46% (x = 42.4) body length; nostril just nearer eye or midway from eye to tip of snout; internarial distance about equal to or just greater than interorbital distance; eye diameter 7%–11% (x = 9.4) body length; mouth subterminal; oral disk entire; spiracle sinistral; anal tube median; oral papilla formula 1-2 or 1-2-1; oral disk width 18%–28% (x = 20.9) body length; oral papilla gap 42%–55% (x = 49.3) oral disk width; labial tooth row formula 2(2)/3; number of labial teeth in a single split row of A-2, stages 29–37, 60–78; number of labial teeth in 0.1 mm measured in middle of one split tooth row in A-2, 5.5–8 (x = 6.6); dorsal body brown, heavily and uniformly mottled or uniform brown uppermost, moderately mottled laterally extending to eyes; ventral body brown, moderately mottled entirely or heavier mottling anteriorly; light to moderate profusion of melanophores on oral disk; light to moderate profusion of melanophores on anal tube; tail either almost uniformly brown or musculature moderately mottled brown, dorsal fin lightly sprinkled with melanophores, dorsalmost fin clear and very few melanophores on ventral fin, only next to musculature.

The preceding larval description is based on samples from Tambopata, Madre de Dios, Peru. The tadpole illustrated by Hero (1990:252) as Leptodactylus wagneri/podicipinus (not examined by me) is most certainly petersii, as petersii is the only member of the complex that occurs within the forests in the areas Hero studied.

ADVERTISEMENT CALL.—There are apparently two major types of calls given by Leptodactylus petersii. Further study is needed in order to determine what the functions of these calls are.

Type 1: Call rate 2.9–4.2 calls per s; call duration 0.04–0.05 s; calls of single pulsatile notes, about 3–4 partial pulses per note/call; calls not noticeably frequency modulated; broadcast frequency range 700–1200 Hz, maximum energy 750–800 Hz; harmonics weakly to strongly developed (Figure 16).

Type 2: Call rate 0.6–1.3 calls per s; call duration 0.03–0.05 s; calls of two juxtaposed notes, first note noticeably pulsatile, with 2–4 partial pulses, second note not noticeably pulsed; first note frequency modulated upward with a fast rise time, second note often frequency modulated downward with a slower fall time than rise time of first note; broadcast frequency range of first note 800–1600 Hz, of second note 1800–2800 Hz; first note with harmonic structure, second note apparently without harmonic structure (Figures 3, 20, 21, 25).

KARYOTYPE.—Unknown.

GEOGRAPHIC VARIATION.—Geographic variation has been discussed within the analyses for “Region 3—Interior Brazil” and “Region 4—Amazonia” and apply to the species as a unit. There is no obvious geographic variation in size when the largest and smallest individuals (> and <2 standard deviations from mean) are examined with the exception that all the smallest individuals come from the Peruvian Department of Madre de Dios and the Bolivian Department of Beni. The largest individuals occur in the Brazilian states of Amazonas, Goiás, Mato Grosso, Pará, and the Department of Loreto in Peru.

Leptodactylus petersii (common name: Peters' thin-toed frog, in Spanish sapito de Peters, i.e. "Peters' toadlet") is a species of frog in the family Leptodactylidae. It is found widely in the Guianas and the Amazon Basin (Bolivia, Brazil, Colombia, Ecuador, French Guiana, Guyana, Peru, Suriname, and Venezuela). It has been confused with Leptodactylus podicipinus and Leptodactylus wagneri, complicating the interpretation of older records and accounts.