The advertisement call of the phytotelm-breeding Melanophryniscus xanthostomus (Anura: Bufonidae)

ABSTRACT Vocalizations are often useful for understanding taxonomic relationships among anuran species. Despite this usefulness, vocalizations are described in only nine of 29 in Melanophryniscus Gallardo, 1961. Here we describe the advertisement call of Melanophryniscus xanthostomus Baldo, Bornschein, Pie, Ribeiro, Firkowski & Morato, 2015 of a population from Serra Dona Francisca, municipality of Campo Alegre, state of Santa Catarina, Brazil. The advertisement call (of three males, total of 17 calls) comprises two segments (the first with short and single notes, followed by a multi-pulsed note), with a duration of 12.194-20.986 s, and dominant frequency of 3101-3618 Hz (first and second segments combined). The advertisement call of M. xanthostomus differs from its congeners mostly by the higher number of pulses in the second segment (294-1033; from 16 to 321 in the other Melanophryniscus species), except Melanophryniscus krauczuki Baldo & Basso, 2004 (1018-1502 pulses in the second segment). This is the first described call of a phytotelm breeding Melanophryniscus, but it presents the same prototype (a compound call formed by two segments, the first composed of short notes followed by a long trill) of its congeners not-phytotelm breedings. This might indicate the advertisement call of Melanophryniscus as a conserved trait and thus can be considered diagnostic for the genus.

摘要：发声特征通常有助于理解无尾两栖类（anuran）物种间的分类学关系。尽管具备此类应用价值，但黑背蟾属（Melanophryniscus Gallardo, 1961）目前已知29个物种中，仅9个的发声特征被记录描述。本研究针对采自巴西圣卡塔琳娜州坎波阿莱格雷市塞拉多纳弗朗西斯科（Serra Dona Francisca）种群的黄腹黑背蟾（Melanophryniscus xanthostomus Baldo, Bornschein, Pie, Ribeiro, Firkowski & Morato, 2015）的求偶鸣唱展开描述。本次研究样本来自3只雄性个体，共计17次鸣唱：该物种的求偶鸣唱包含两个段落，第一段由短促的单音节鸣音构成，第二段为多脉冲音节；鸣唱时长介于12.194~20.986秒，综合两段的主频范围为3101~3618赫兹（Hz）。黄腹黑背蟾（M. xanthostomus）的求偶鸣唱与同属其他物种的差异主要体现为第二段脉冲数更高：其脉冲数为294~1033，其余黑背蟾属物种的脉冲数仅为16~321，仅克氏黑背蟾（Melanophryniscus krauczuki Baldo & Basso, 2004）例外，其第二段脉冲数为1018~1502。本研究首次记录了黑背蟾属中依赖植物贮水器繁殖（phytotelm breeding）的物种的鸣唱，但其鸣唱原型与同属非植物贮水器繁殖物种保持一致：均为双段式复合鸣唱，第一段由短促单音构成，随后接续一段长颤音。上述特征表明黑背蟾属的求偶鸣唱属于保守性状，因此可作为该属的分类鉴定特征。