Santa Fe Dwarf Frog

Diagnosis: Physalaemus santafecinus is very similar to P. biligonigerus, differing only in the advertisement call and the following morphological characters: smaller body size (to 34 mm SVL in P. santafecinus vs. to 40 mm in P. biligonigerus); somewhat larger head; snout sharply truncate and more projecting (vs. gently truncate and slightly projecting in P. biligonigerus); more glandular skin (vs. loose, smooth skin with flat and round glandular areas in P. biligonigerus); split metasternum (vs. notched in P. biligonigerus); and whitish testicles (vs. black in P. biligonigerus) (Cei 1980). In addition, P. santafecinus can be distinguished by having inguinal gland coloration the same as the dorsal coloration, vs. much darker inguinal glands in P. biligonigerus (Brusquetti et al. 2009). Cei (1980) describes the very similar species P. biligonigerus as having a variable dorsal color pattern, from uniform brownish or greenish to dark longitudinal stripes or irregular marbling; dark bands on the limbs; immaculate white venter. Description (for the related species P. biligonigerus): Maximum SVL of 34 mm; no sexual dimorphism in size. Head small and broad, and triangular in shape. Snout rounded when viewed from above, gently truncate and slightly protruding in profile. Nares laterodorsal, at the tip of the snout. Canthus rostralis rounded; loreal region somewhat indistinct. Maxillary teeth weakly developed; vomerine teeth lacking. Tongue is small and oval, entire and free at the posterior. Eyes are lateral and are moderately prominent, with a diameter roughly equal to the snout length. Tympanum not visible. Supratympanic fold is weak and indistinct. Fingers are slender. Subarticular and metacarpal tubercles are well-developed and rounded. Toes lack webbing but have narrow fringes. Subarticular tubercles are prominent and conical-shaped. Metatarsal tubercles are sharply prominent and are shovel-shaped. Tarsal tubercle distinct though small. Heel tubercle and tarsal fold are absent. Skin is loose and smooth with flat rounded glandular patches on the dorsum; on the venter the skin is smooth; on the ventral surfaces of the thighs the skin is granular. Discoidal and thoracic folds are present. Gular region of males has dark skin folds. Large inguinal gland (Cei 1980).The tadpole measures about 24 mm SVL at stage 38. Tail length is about twice as long as the. It has an ovoid, slightly depressed body, with a maximum width greater than that at the level of bodythe eyes. Eyes are positioned dorsolaterally. The snout is rounded both when viewed from above and when viewed in profile. Nostrils are dorsal and are oval-shaped. The oral disc is subterminal and anteroventral. Marginal papillae are present in a single row with a wide median rostral gap. A row of intramarginal papillae is also present in the infraangular region. The upper jaw sheath is arch-shaped while the lower jaw sheath is V-shaped; both are serrated. LTRF is 1, 1-1/1-1. The spiracle is medial and sinistral, while the vent is dextral. The dorsal fin is higher than the ventral fin and begins at the tail-body junction, while the ventral fin originates on the abdomen. Both fins are about the same height as the caudal musculature. The tail tip is slightly curved. For a detailed description of buccopharyngeal morphology, see Perotti and Céspedez (1999). Perotti and Céspedez (1999) noted that the tadpole of P. santafecinus can be distinguished from that of its syntopic congener P. biligonigerus by its LTRF (1, 1-1/1-1 for P. santafecinus vs. 1,1-1/2 for P. biligonigerus), by the shape of the lower beak (V-shaped for P. santafecinus, U-shaped for P. biligonigerus, by the oral disc marginal papillae (intramarginal lateral papillae present in the infraangular region for P. santafecinus vs. none in the infraangular area for P. biligonigerus), and by the location of the spiracle (medial and sinistral in P. santafecinus vs. posterior and sinistral in P. biligonigerus). Larval P. santafecinus can be distinguished from larval P. natteri by a smaller body size at stage 38 (22.04 mm SVL vs. 28 mm SVL), the presence of intramarginal lateral papillae in the infraangular region (vs. not present in P. natteri), and a dextral vent (vs. medial in P. natteri). Tadpole labial teeth were examined by Vera Candioti and Altig (2010) as part of their survey of larval tooth shape variation.In preservative, the larval body is light brown with more concentrated pigment present in the interocular region, near the nostrils, and on the epaxial musculature up to the point where the dorsal fin originates. Fins and tail are light brown. Limbs have pigment on the dorsal surfaces. The venter is transparent (Perotti and Céspedez 1999).Physalaemus santafecinus was first described by Barrio (1965). Although it was not clear whether this species occurs in Paraguay (since Lavilla et al. (2004) state that Paraguayan populations are not P. santafecinus, but Brusquetti and Lavilla (2006) suggested that this species might indeed occur in adjacent Paraguay), recent work by Brusquetti et al. (2009) has confirmed its presence in Paraguay. Specimens (males, females and juveniles) were collected in 2006 and deposited at the Museo Nacional de Historia Natural del Paraguay (MNHNP 11137-57) and the Colección Biológica Arnoldo da Winkelried Bertoni del Instituto de Investigación Biológica del Paraguay (IIBP-H 274, 279-0, 283, 287, 295, 297, 299, 308-12, 328-34, 658-9). The initial Paraguayan specimen originally referred to this species (USNM 253137), by McDiarmid and Foster (1987), is considerably bigger than P. santafecinus and its identity has not been determined (Brusquetti et al. 2009).

Found in Argentina, in Corrientes and Santa Fe provinces (Cei 1980) as well as Chaco Province (Lavilla et al. 2004), and Paraguay, in Departamento Ñeembucú, Distrito General Díaz, Estancia San José (Brusquetti et al. 2009). Found in seasonal wetlands (humid shrub forests) at elevations from 30-60 m asl (Lavilla et al. 2004; Perotti and Céspedez 1999). The Paraguayan locality is within the Humid Chaco ecoregion, and individuals were collected in flooded grasslands as well as on sandy soil between two patches of forest, in an area that had been disturbed by cattle (Brusquetti et al. 2009).

In Paraguay, specimens were collected after heavy rains, in flooded grasslands (Brusquetti et al. 2009). It breeds in temporary shallow ponds (Perotti and Céspedez 1999), during January and February (Barrio 1965). The advertisement call has shorter notes and more notes per call than that of P. biligonigerus (Barrio 1965; Brusquetti et al. 2009). The clutch consists of about 500 eggs (Gallardo and Varela de Olmedo 1992), laid in a hemispherical foam nest that floats on the water's surface (Zaracho et al. 2005). The foam nest is about 2-3 inches in height (Gallardo and Varela de Olmedo 1992) and 7 inches in diameter (Zaracho et al. 2005). Eggs each measure 0.9 mm in diameter and are yellow-gray (Zaracho et al. 2005). Tadpoles are suspension raspers (Perotti and Céspedez 1999). This species burrows underground when it is dry (Lavilla et al. 2004). Adults are active foragers and consume mainly isopterans (termites) (Dure 1998). Syntopic with P. biligonigerus (Cei 1980; Perotti and Céspedez 1999), but breeds at a different time (Jan.-Feb. vs. Sept.-Apr. for P. biligonigerus).

Occurs in at least two protected areas within Argentina: the Ibará Provincial Reserve, and the Junkanigas RAMSAR site. It appears to be more common than first thought and is an adaptable species that can tolerate disturbed habitat (Lavilla et al. 2004).

Diagnosis a smaller paludicoline frog, almost identical to the sibling species P. biligonigerus from which especially diverges by the mating call and some little evident morphological characters.

Present in the provinces of Santa Fe, Corrientes and Chaco in Argentina.

óleo

Adult morphology Snout-vent up to 34 mm. Very similar to P. biligonigerus. Besides its smaller size, it also differs in the head somewhat larger; in the sharply truncate and more protunding snout; in the length of the indleg, the heel reaching beyond the shoulder when hindleg is adpressed; in the more glandulous skin, and some osteological features. Larval morphology Ten tadpoles in Stages 35-40 (Gosner, 1960). The body of the tadpole is ovoid, slightly depressed, total length = 24.04 mm (SD = 1.70, N = 4) at Stage 38. Maximum width of body is greater than width at eye level; eyes dorsolateral; snout rounded in dorsal and lateral views; oral disc subterminal, with marginal papillae in single row and wide rostra1 gap; row of intramarginal papillae in infraangular area; labial teeth strongly keratinized and pigmented with serrated free margins; upper beak wider than high and curved; lower beak V-shaped; tooth row formula 2(1)/2(1); nostrils dorsal, oval, and separated by a distance of 0.66 times interocular distance; spiracle sinistral with opening directed dorsally; diameter of opening is less than tube diameter; venter transparent. Tail length 66% of total length. Dorsal fin originates at tail-body junction; ventral fin originates on abdominal region; dorsal fin higher than ventral fin; tip of tail slightly curved; anal tube dextral, opening in line with ventral fin. In preserved specimens, dorsum lightly pigmented brown with major concentration of pigment in interocular zone, near nostrils, and convering epaxial musculature up to origin of dorsal fin; fins and remainder of tail lightly pigmented; limbs pigmented dorsally.

LC. Least Concern.

Physalaemus santafecinus is a species of frog in the family Leptodactylidae. It is found in Argentina and possibly Paraguay. Its natural habitats are temperate grassland, intermittent freshwater lakes, intermittent freshwater marshes, and pastureland. It is threatened by habitat loss.