Bioacoustics of Microkayla teqta

Diagnosis. A member of Craugastoridae assigned to the genus Psychrophrynella based on biogeographical and morphological grounds. Two other genera of Holoadeninae (sensu Padial et al. 2014 ) occur in Bolivia : Noblella and Oreobates . Noblella has terminal phalanges narrowly T-shaped, discs and distal circumferential grooves present distally, and tips of at least toes III and IV acuminate (terminal phalanges knob-shaped, circumferential grooves absent, and tips of all digits rounded in Psychrophrynella ); Oreobates has dentigerous processes of vomers prominent (absent in Psychrophrynella ) ( Duellman & Lehr 2009 ). Psychrophrynella teqta is diagnosed by the following combination of characters: (1) medium size (maximum SVL 27.8 mm ), body robust, legs short (average TL + FL between 69.8–75.7% SVL; n = 8); (2) tympanic membrane absent, tympanic annulus present, visible under the skin; (3) first finger slightly shorter than second; (4) tips of digits slightly swollen, not expanded laterally; (5) webbing of toes and lateral fringes absent; (6) two metatarsal tubercles, tarsal fold absent; (7) dorsal skin and flanks shagreen to pustulate; dorsolateral folds irregular, reaching midbody; ventral skin areolate; (8) snout rounded in dorsal view and in profile; (9) color on dorsum variable, from dark brown to beige, with or without irregular cream, reddish-brown blotches; (10) color on venter variable, from dark brown to cream, with a pattern of irregular blotches cream, yellow, or gray. Psychrophrynella teqta is distinguished from other species in the genus for which the call is known, by its pulsed call. Regarding morphology and coloration, the new species is superficially similar to P. wettsteini (Parker) and P. condoriri ( De la Riva, Aguayo and Padial), which furthermore are species whose type localities are geographically close to that of P. teqta . The new species is distinguished from P. wettsteini mostly by its smaller size (maximum SVL in P. wettsteini 33.4 mm ) and shorter legs (TL + FL> 80% SVL in P. wettsteini ); the color pattern in P. wettsteini is mostly gray or reddish-brown above with or without pale spots and ventrally cream with reddish-brown spots or reticulations, while in P. t e q t a coloration is extremely variable and often there are reddish and yellow blotches, which are never present in P. wettsteini . From P. condoriri , the new species differs mostly by having dorsal skin shagreen or rugose (mostly smooth in P. condoriri ), and a variable color pattern both on dorsum and venter, including reddish and yellow blotches (dorsum brown with diffuse darker areas, venter gray with brown markings). The small species P. chacaltaya ( De la Riva, Padial and Cortéz) is found in the upper Zongo Valley, not far from the type locality of P. teqta , and it is easily distinguishable from the new species by being much smaller (maximum SVL 20.4 mm ), and having a different color pattern, consisting of dorsum dark grayish-brown with darker marks and venter uniformly cream or brown with irregular brown blotches.

Distribution and ecology. This species is known only from the type locality ( Fig. 3 ). The locality of Pablo Amaya is surrounded by agricultural fields and pastures for llamas, leaving very little suitable habitat for Psychrophrynella frogs. The new species was on the more humid slopes passing the village, midway between the old road and the small river that flows along the valley. Individuals were found under stones by day. One individual (MNCN 45704) was on the bank of a narrow, small canyon, and the rest were under the scattered stones pertaining to the ruins of an old construction ( Fig. 4 ), which created a micro-environment with humidity and vegetation highly suitable for the species. No other species of anurans were found in syntopy. The type locality of P. condoriri is 5.25 km to the northwest of Pablo Amaya, that of P. wet tstei ni is 45 km to the southeast, and P. cf. chacaltaya occurs 25.5 km also to the southeast, in the upper Zongo Valley. Natural history. Reproduction data on species of Psychrophrynella are not easy to gather. So far, only the eggs of P. w e t t s t e i n i and P. illampu ( De la Riva, Reichle and Padial) had been observed or photographed [ Ergueta 1993 ; De la Riva 2007; recently, nests of P. illimani ( De la Riva and Padial) were found and photographed by A. Muñoz and colleagues (A. Muñoz, in litt.)]. We found two clutches of P. teqta under stones, each of them guarded by a male occupying a small chamber. The first clutch contained 41 well-developed eggs (average diameter 5.11 mm , n=5; Fig. 5 ), containing embryos that moved frequently inside the egg capsule; the guarding male (MNCN 45703) was quite small ( 23.5 mm SVL). This clutch proved to be difficult to extract from the ground, for it was deeply intermingled with small, very slender grass roots. The second clutch had 28, smaller, yellowish-white eggs (average diameter 4.74 mm , n=5). In both cases, the males remained on or beside the eggs, presumably offering some type of parental care. They had the snout slightly protruding, of a translucent gray color, different from the rest of the head; this probably indicates certain burrowing activity to construct and maintain the chambers where they guard the clutch. The holotype had large, developed oviducts but no female among our sample showed oviductal eggs. Advertisement call. Calls of Psychrophrynella are remarkably similar across species, and most calls consist of a simple, tonal, rather short, high-pitched note [so far, the most divergent call is that of P. saltator ( De la Riva, Reichle and Bosch), consisting of series of 7–36 short notes; see De la Riva 2007]. At the time of collecting P. teqta (05–07 h pm) some frogs were calling. Surprisingly, calls were pulsed, not tonal. Thus, it was very important to capture a voucher calling male in order to be sure that the recorded call indeed belonged to the new species. The voucher male (MNCN 45702) was in the middle of a thick mass of moss, over a large rock. At an air temperature of 10.8ºC and a relative humidity of 77%, this male emitted pulsed calls consisting of a simple note with an average duration of 270 ms (n=8; Fig. 6 ), uttered in irregular series of several calls. Based on the total time of recording, the overall call rate is approximately 6.5 calls/minute (average interval between calls, 2,365 seconds; n=6). Each call has 16–19 pulses of variable duration, being the first pulses shorter. For example, the first pulse lasts, on average, 8 ms, while the last pulse has an average duration of 26 ms. The pulse amplitude is also progressively higher along the call, with a maximum at approximately 221 ms from the onset of the call (i.e., call rise time 82% of call duration). The spectral structure of this advertisement call is characterized by an average dominant frequency of 2.2 kHz, corresponding with the fundamental frequency of the signal and lacking frequency modulation. The call shows 3–5 apparent harmonics, of which the first one accounts for an average of 95% of the total signal energy ( Fig. 6 ).