Strabomantidae

Guayasamin, Juan M. & Funk, Chris, 2009, The amphibian community at Yanayacu Biological Station, Ecuador, with a comparison of vertical microhabitat use among Pristimantis species and the description of a new species of the Pristimantis myersi group, Zootaxa 2220, pp. 41-66 : 47-49

Family: Strabomantidae

This family is restricted to tropical and subtropical South America ( Hedges et al. 2008) and has a recognized diversity of 556 species (AmphibiaWeb 2009). All strabomantids seem to have direct development, a trait that might have facilitated their diversification in moist areas where standing water is rare (e.g., cloud forests). Most species in this family lack webbing between fingers and toes. Strabomantids represent the most diverse clade in YBS, with 6 described and 3 undescribed species. We follow the taxonomy proposed by Heinicke et al. (2007) and Hedges et al. (2008).

Pristimantis eriphus (Plate 3). Described by Lynch and Duellman (1980). This species is distinguished from other anurans by having many small conical tubercles on dorsal skin, one prominent tubercle on the upper eyelid, conical ulnar and tarsal tubercles, and a conical tubercle on heel. In life, Pristimantis eriphus has a pale green dorsum with dark olive to green-brown markings; its flanks and hidden surfaces of limbs have a black and white pattern; the venter is white to greenish-white with dark brown to black reticulations; the iris is orange-red to reddish copper. At YBS, SVL in adult males is 16.3–21.4 mm (n = 16); in adult females, SVL 18.6–33.2 mm (n = 16).

Pristimantis gladiator (Plate 4). Described by Lynch (1976b). In life, Pristimantis gladiator has a brown to orange-brown dorsum with dark brown markings, and a black groin with orange to red spots. Other diagnostic traits of P. gladiator include the presence of low ulnar and tarsal tubercles and low, non-pungent tubercles on the upper eyelid. In adult males, SVL 14.9–16.9 mm (n = 5); adult females unknown (updated from Lynch 1976b). None of the other frogs at YBS have a black groin with orange-red spots. This small species has been found by day under rocks and logs ( Lynch 1976b).

Pristimantis inusitatus (Plate 4). Described by Lynch and Duellman (1980). This species is distinguished from other frogs mainly by its dorsal color pattern (see below) and by having conical ulnar and tarsal tubercles, a conical tubercle on heel, and a conical tubercle on the upper eyelid. In life, Pristimantis inusitatus has a sexually dimorphic coloration. Females have a green dorsum with yellow to yellow-green tubercles, a pale lemon yellow to yellow groin, white throat with green markings, white venter, and yellow-cream to yellow iris with black reticulations. Males differ by having a brown-green to pink-brown dorsum with dark brown marks, clearly banded limbs, a pale yellow throat with small white spots, and a white venter (translucent on its posterior portion). At YBS, SVL in adult males is 13.1–17.5 mm (n = 15); in adult females, SVL 22.2–26.0 mm (n = 10).

Pristimantis leucopus (Plate 5). Described by Lynch (1976c). A species diagnosed by having an upper eyelid with few small flat tubercles or lacking tubercles, low and inconspicuous ulnar and tarsal tubercles, and by lacking tubercles on the dorsum. In life, this species has a green to brown dorsum with dark brown marks, flanks mostly dark gray with greenish-brown mottling, and throat, chest, and belly reddish-orange with brown mottling that is most conspicuous on the throat. The groin and ventral surfaces of legs are dark gray to black. Pristimantis leucopus is one the largest species found at YBS; SVL in adult males is 29.7–37.8 mm; in adult females, SVL 39.2–44.0 mm ( Lynch & Duellman 1980; this work).

Pristimantis cf. petersi (Plate 5). Described by Lynch and Duellman (1980). This species is characterized by having smooth dorsal skin, a papilla at the tip of the snout, and one conical tubercle on the upper eyelid. In life, Pristimantis petersi usually has a pale green to dull green dorsum with no distinct markings ( Lynch & Duellman 1980), but individuals found at YBS have a brown to orange-brown dorsum with dark brown markings. At YBS, SVL in adult males is 15.7–21.2 mm (n = 10); in adult females, SVL 24.0– 27.5 mm (n = 5).

Remarks. Because of the differences in color pattern between the usual Pristimantis petersi and the population found at YBS, we consider the identification as tentative. Additionally, individuals (especially females) found at YBS are larger than those reported in the literature (in 35 males, SVL = 14.5–19.9 mm; in 8 females, SVL = 20.3–23.1 mm; Lynch & Duellman 1980). In Funk et al. (2003), Pristimantis cf. petersi was referred to as Eleutherodactylus sp. 2.

Pristimantis w-nigrum (Plate 5). Described by Boettger (1892). This frog is easily recognized by having, in life, a color pattern of yellow with black markings on the groin, anterior and posterior surfaces of thighs, and concealed shank. Other distinctive traits include having a light brown dorsum with brown markings, a prominent tympanum, and a first finger that is longer than the second. At YBS, SVL in adult males is 31.9– 40.2 mm (n = 5); no adult females have been found. Lynch and Duellman (1980) report the following body size for the species: in adult males, SVL = 29.3–46.8 mm (n = 32); in adult females, SVL = 44.4–56.6 mm (n = 15).

Remarks. Pristimantis w-nigrum is unusual among Andean amphibians by having a broad distribution that includes the Pacific and Amazonian slopes of the Andes, as well as the high Andes of Colombia and Ecuador (800–3200 m; Lynch & Duellman 1997). Given the importance of the Andes in the speciation of amphibians ( Lynch & Duellman 1997; Guayasamin et al. 2008), it is likely that P. w-nigrum actually represents a species complex.

Caecilia orientalis (Plate 5). — Described by Taylor (1968). Family Caeciliidae . Caecilians are subterranean or aquatic amphibians found throughout much of the tropics ( Duellman & Trueb 1994). At YBS, only one species of caecilian has been reported, Caecilia orientalis ( Funk et al. 2004) , which is easily identified by having an elongated and limbless body with a blue-gray to lavender dorsal coloration. Funk et al. (2004) described the egg clutch and nest site of C. orientalis , confirming that this caecilian is oviparous. Caecilia orientalis is the main prey item of the Barred Hawk, Leucopternis princeps ( Greeney et al. 2008) . At YBS, SVL in adult males is 320–356 mm (n = 2); in females, SVL = 348–458 mm (n = 2).

FIGURE 4. Microhabitat use of sympatric species of Pristimantis at Yanayacu Biological Station. Box plots of the vertical distance above the ground where frogs were encountered at night. Separate box plots are shown for adults and juveniles for species in which at least 10 individuals of each stage were found. Grey = all individuals; black = adults; and white = juveniles. The boundaries of boxes indicate the 25th and 75th percentiles; the line within the box is the median; error bars are the 10th and 90th percentiles; and points below and above error bars are outliers. Sample sizes (numbers of frogs) are shown above plots in parentheses. Species grouped with a horizontal dashed line and letter did not have significantly different height means (for all individuals; Tukey-Kramer method, P> 0.05).