Bioacoustics of Eleutherodactylus wixarika

Etymology . Eleutherodactylus wixarika is a patronym honoring the Wixárika people, better known by their Spanish name, Huicholes. Once widespread in the states of Nayarit, Jalisco, Zacatecas, Durango and San Luis Potosí, the Wixárika people still inhabit the area around the type-locality of this frog, and the Sierra Huichol mountain range remains one of the last outposts of their language and culture. Advertisement calls. Like other members of the subgenus Syrrhophus , the advertisement call of these species consists of a short note best described as a “chirp” or “peep”. These notes are relatively narrow band (<500 Hz), nearly pure-tone bursts of acoustic energy organized into a discrete train repeated about 6 times per minute ( Table 1 , Fig. 10 ). The fundamental frequency contains nearly the same amount of energy as the dominant frequency in both species (not shown). Compared to E. wixarika , the call of the larger species E. grunwaldi is much shorter (70 vs. 130 ms), ascends to its dominant frequency more rapidly, and has a lower dominant (and thus fundamental) frequency (2100 vs. 2700 Hz). The calls of both species show substructure within a call, but the pulses of acoustic energy are irregular in timing and duration. The signals of both species show very slight frequency modulation from beginning to end. Although Syrrhophus may produce an irregular introductory trill prior to a call bout ( Fouquette 1960 ), our recordings do not contain any trills. E. grunwaldi E. wixa rika Dominant frequency (kHz) 2.13 ± 0.02 2.75 ± 0.04 Call length (ms) 70 ± 10 130 ± 40 Call rate (/m) 6.13 ± 1.35 6.43 ± 2.74 Call rise time (ms) 20 ± 10 90 ± 30 Rényi spectral entropy 5.46 ± 0.52 5.74 ± 0.36 Spectral flatness measure 0 0 Discussion Advertisement calls. Spectral and temporal acoustic properties of male advertisement calls differ between the two new species described here. Few descriptions (and even fewer recordings) of Syrrhophus advertisement calls have been published. Fouquette (1960) described the calls of Eleutherodactylus marnockii , E. pipilans , and E. nitidus . Dixon (1957) reported reciprocal calling by female E. angustidigitorum , a behavior that has been reported in at least two other eleutherodactylids ( Schlaepfer & Figeroa-Sandí, 1998 ; Stewart & Rand, 1991 ). It is not known whether female E. grunwaldi or E. wixarika call. The small size of Syrrhophus imposes constraints for acoustic communication ( Gerhardt & Huber, 2002 ), namely the limited communication range of high-frequency calls. Like many other eleutherodactlyids, Syrrhophus increase their broadcast range by calling from elevated perches. Males of some species call from rock crevices ( Fouquette 1960 ), which may serve to amplify the signal by acting as a secondary resonator ( Penna & Solís, 1996 ). Evolutionary relationships and biogeography. Twenty-four species of Syrrhophus occur in mainland Central and North America , all of them included in the Eleutherodactylus (Syrrhophus) longipes species series as defined by Hedges et al. (2008) . This species series is further split into six species groups, which were first defined by Lynch (1970) and revised by Hedges (1989) and Hedges et al. (2008) .