Status, vocalization and breeding biology of two species of African bullfrogs (Ranidae: <i>Pyxicephalus)</i>

Channing, Alan; Preez, Louis Du; Passmore, N. I.

doi:10.1111/j.1469-7998.1994.tb06061.x

Cited by 20 publications

(36 citation statements)

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“…Greater moon light prolonged spawning at the study site even though P. adspersus spawns predominantly during day light (Balinsky 1969;Channing et al 1994). This was possibly because moon light facilitated foraging at night around the artificial dams, which enabled males to call, fight, and/or spawn over a longer period.…”

Section: Revealed That Variousmentioning

confidence: 95%

“…Thus the largest count of males, and the duration of each observed spawning event was determined. Females were not counted because their smaller size and inconspicuous behaviour (Channing et al 1994;Cook 1996) made them difficult to detect.When eggs, tadpoles or newly-metamorphosed froglets were found without spawning having been observed, we estimated the date of spawning from the development of offspring (Gosner 1960;Van Wyk et al 1992;Haas 1999) and measurements of daily rainfall from Diepsloot Nature Reserve. Hence, for Summers 2-5, we estimated the annual number of spawning events as the sum of all spawning events that were observed or revealed by eggs, tadpoles or froglets.…”

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confidence: 99%

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confidence: 99%

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Spawning and non-breeding activity of adult giant bullfrogs (Pyxicephalus adspersus)

Yetman

Ferguson

2011

African Journal of Herpetology

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Abstract.-Populations of the Near-Threatened giant bullfrog (Pyxicephalus adspersus)have been poorly monitored due to the unpredictable appearance of this species aboveground. To better understand the activity of P. adspersus we quantified spawning by a population during five summers, and the activity of twenty adult frogs radio-tracked at the same site ca. twice weekly during the first three summers. In addition we examined animal activity, and population spawning in relation to meteorological variables, day of season, and moon light. During the six-month summer period, males and females, respectively, spent 10 ± 7 and 3 ± 2 days at water, and 22 ± 5 and 13 ± 5 nights active. Greater proportions of radio-tracked animals moved overland, and/or foraged at night, around full moon, after heavy rainfall, when cooler, and less windy conditions prevailed. More animals were found at water, or on land during the day, and population spawning was more likely, earlier in summer, following heavier rainfall. Spawning occurred most frequently, in descending order, during December, January, and November, and was triggered by 40 ± 16 mm rain in 24 h. Spawning events lasted 2 ± 1 days, but were prolonged around full moon.Numbers of males at spawning events varied between 30 and 500 males, and were positively correlated with the previous day's rainfall. Annually 6 ± 1 spawning events occurred, and numbers of annual spawning events were positively correlated with total summer rainfall. Results of this study show that single counts of spawning adults will often result in gross underestimates of population size, and therefore, long-term adult counts are necessary to detect real population trends. Due to the unpredictable activity of adults, however, it may be more practical to monitor, within certain areas, the number of aquatic sites where breeding occurs, for improved conservation management of P. adspersus. 3Although photoperiod and the lunar cycle provide predictable cues that amphibians may use to synchronize their behaviour (Fitzgerald & Bider 1974;Both et al. 2008;Canavero & Arim 2009;Grant et al. 2009), the activity of many species is ultimately dictated by unpredictable climatic variables because of their permeable skin and ectothermic bodies (Duellman & Trueb 1994). Among these, precipitation tends to exert the greatest influence (Bulger et al. 2003;Lemckert & Brassil 2003), but temperature (Howard 1978;Van Gelder et al. 1986), humidity (Bellis 1965;Bartelt et al. 2004), wind (Penman et al. 2006Philips et al. 2007), light intensity/cloud cover (Jameson 1955;Blankenhorn 1972), and barometric pressure (Blankenhorn 1972) can also significantly affect amphibian activity. Amphibians in dry and/or cold environments are most limited by suitable warm, wet conditions, making it difficult to predict their behaviour or even their presence (e.g., Bulger et al. 2003;Bartelt et al. 2004;Goldberg & Schwalbe 2004). This can represent a serious challenge for effective conservation management of threatened amphibian taxa (e.g., Penman et al...

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Section: Revealed That Variousmentioning

confidence: 95%

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confidence: 99%

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Spawning and non-breeding activity of adult giant bullfrogs (Pyxicephalus adspersus)

Yetman

Ferguson

2011

African Journal of Herpetology

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“…revised the genus in southern Africa, examining most of the holdings of southern African museums, and described the subspecies Pyxicephalus adspersus angusticeps from Mozambique. In a review of the status of Pyxicephalus in southern Africa, Channing et al (1994) provided detailed accounts of the breeding biology and vocalizations of P. adspersus from Bloemfontein, and a species of Pyxicephalus from Beira, Mozambique, concluding that they were not conspecific and that two species of bullfrogs occurred in southern Africa. Channing et al (1994) elevated P. adspersus edulis to species rank, at the same time synonymizing the TABLE 1.…”

Section: Introductionmentioning

confidence: 99%

“…Species boundaries in Pyxicephalus are poorly understood, particularly those between P. adspersus and P. edulis. Despite their obvious morphological differences, P. edulis was twice synonymized with P. adspersus and twice removed from synonymy with P. adspersus (Boulenger 1882;Loveridge 1936Loveridge , 1950Poynton 1964;Channing et al 1994). revised the genus in southern Africa, examining most of the holdings of southern African museums, and described the subspecies Pyxicephalus adspersus angusticeps from Mozambique.…”

Section: Introductionmentioning

confidence: 99%

Revalidation of Pyxicephalus angusticeps Parry, 1982 (Anura: Natatanura: Pyxicephalidae), a bullfrog endemic to the lowlands of eastern Africa

Scott¹,

Visser

Yetman

et al. 2013

Zootaxa

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Pyxicephalus currently contains three recognized species, viz. P. adspersus, P. edulis and P. obbianus, the former two of which have a long history of confusion. Parry (1982) described P. adspersus angusticeps from Beira, Mozambique, which was synonymized with P. edulis. We re-examine the taxonomic status of Pyxicephalus taxa from Mozambique, examining the types and contrasting them to congeners throughout Africa. Morphological characters previously used to delimit species in Pyxicephalus are examined, and problems with some identified. Additional diagnostic characters and their variation in Pyxicephalus are discussed, and a revised key is provided. Confusion among species in the genus, type localities, literature and folklore led to P. adspersus angusticeps being incorrectly synonymized with P. edulis. We formally revalidate P. angusticeps, and designate a lectotype for P. edulis. The identity of voucher specimens from previous work suggests that the breeding ecology of P. angusticeps is distinct from that of P. adspersus and P. edulis, and that the advertisement call of P. angusticeps was used as part of the evidence for elevating P. edulis out of synonymy with P. adspersus. The previous confusion of P. adspersus and P. edulis does not affect the recognition of P. angusticeps. The wider implication of the previous misidentification of P. angusticeps as P. edulis is that most of the museum material labeled as P. adspersus from East Africa is P. edulis, and most of the museum material labeled as P. edulis from East Africa is P. angusticeps. This conclusion has been confirmed from East African museum material thus far examined.

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Osteology and skeletal development ofPyxicephalus adspersus (Anura: Ranidae: Raninae)

Sheil

1999

J. Morphol.

105

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Status, vocalization and breeding biology of two species of African bullfrogs (Ranidae: Pyxicephalus)

Cited by 20 publications

References 1 publication

Spawning and non-breeding activity of adult giant bullfrogs (Pyxicephalus adspersus)

Spawning and non-breeding activity of adult giant bullfrogs (Pyxicephalus adspersus)

Revalidation of Pyxicephalus angusticeps Parry, 1982 (Anura: Natatanura: Pyxicephalidae), a bullfrog endemic to the lowlands of eastern Africa

Osteology and skeletal development ofPyxicephalus adspersus (Anura: Ranidae: Raninae)

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