Atelopus pachydermus (Schmidt 1857)

Atelopus pachydermus (Schmidt)

Phirix pachydermus O. Schmidt, 1857:15 [type locality: “Neu-Granada”]: 1858:257, pl. 3: fig. 26.

A.[telopus] pachydermus.—Rivero, 1963:107; 1968:23.

Atelopus pachydermus.—Rivero, 1965:138.

HOLOTYPE.—In the Zoological Museum of Cracow, Poland. Present condition not known. Schmidt (1858) gave additional information concerning the type locality, stating it to be “Westen von Neu-Granada, bei Bonaventura, in einer Höhe von 5000′.”

DESCRIPTION.—Snout from above blunt, rounded, not projecting, distinct angle in canthus at nostril, canthi from nostril to corner of eye form straight line, angled slightly outward. Canthus and outer eye margin slightly fleshy, with distinct ridge from posterior corner of eye to end of head. Dorsum of head flat, without ridges, tubercles, or fleshy prominences; eye does not protrude dorsally. Snout from side slightly protrusive beyond end of lower jaw; nostril directed laterally, slightly below canthus; loreal region weakly concave; eye slightly overhung by fleshy edge of eyelid; temporal region without tubercles or spines, but in some individuals with glandular swellings. Dorsum of body broad, flat, with minute wrinkling and folding; in some individuals scattered, rounded, glandular prominences. Sides of body studded with rounded, glandular swellings, which are usually covered with several to many whitish spinules. Chin, chest, and belly wrinkled or lined, but without pustules.

Forelimb short, stout in males, more slender in females, forearm more fleshy than upper arm in both sexes; dorsum of arm with glandular swellings, rest smooth with wrinkles or folds. When arm is pulled back along body, digits reach level of hind leg perpendicular to body in females, not so far in males. Forefoot slightly fleshy, webbing very reduced, with all digits distinct and free; first digit more swollen than others, wth horny excrescence from tip of digit to base in males, covering a raised hump of flesh, second digit with cornified area near base of digit. Subarticular tubercles absent, but palm with many raised glandular areas, often with pair at base of each of second and third digits; large palmar tubercle, less prominent plantar tubercle. Tips of digits slightly swollen.

Hind limb rather stout, occasionally glandular along femora, more often heavily wrinkled or folded. Tibiotarsal articulation reaches to points between end of head and arm insertion when carried forward along body; heels do not overlap when tibiofibulae are parallel to femora at right angles to body. Entire foot with somewhat fleshy web, covering all but tips of first and second toes; extends to tips of other digits, but is deeply incised between them. No subarticular tubercles, no tubercles on sole, outer metatarsal tubercle low, rounded, somewhat indistinct, inner metatarsal tubercle ovate and low.

COLOR IN ALCOHOL.—The typical pattern for this species is shown in Figure 25. It may be described in general as: ground color or entire body cream-yellow, with irregular black vermiculations and spots dorsally, which may be so heavy as to cover head and back completely. Sides, venter, and legs also spotted, stippled, and vermiculated with black, with belly and undersides of limbs less spotted than elsewhere. Color patterns extremely variable.

COLOR IN LIFE.—The lighter dorsal areas are bright yellow. Many of the warts and pustules have white tops. The ventral surfaces are white in almost all individuals, but some may have orange areas or spots, and some have red bellies, similar to those seen in specimens of ignescens from nearby localities.

HABITAT.—This high altitude species is extremely common in the vicinity of Papallacta, where they were found along the borders of the Río Papallacta, under rocks and stones in moist, spongy, runoff areas.

VARIATION.—All species of Atelopus tend to be variable in coloration, but the available material of A. pachydermus shows a striking amount of variability. Figures 26 and 27 show a series of adults from the immediate environs of Papallacta, arranged to show the decrease in amount of light pigment in the series. While no individuals were taken in the region of Papallacta which lack the dark pigment entirely, some of the specimens from the region of Oyacachi are apparently entirely free of any dark spotting and mottling, and in life must present a striking golden appearance. In addition to the variation in the amount of pigment present in adults, there is a distinct ontogenetic color change. Individuals 27 millimeters or less in body length lack the strong contrast between the dark and light areas seen in adults. The dorsal areas that presumably will be yellow in adults are dark gray or light brown in juveniles, and the darker areas are not strongly differentiated from the lighter. Some juveniles appear almost totally black dorsally. Ventral color in the juveniles is the same in adults.