Pub Date : 2023-08-13DOI: 10.1080/21564574.2023.2237035
A. Staniewicz, G. McCabe, M. Holderied
ABSTRACT Acoustic techniques are rapidly becoming powerful tools for species monitoring and biodiversity assessment. These methods can be particularly appropriate for forest-dwelling crocodiles which are difficult to survey visually. However, basic vocal-repertoire data is lacking for many of the poorly known species. Here, we used passive acoustic recorders to capture 97 spontaneous vocal signals from a pair of captive adult African dwarf crocodiles (Osteolaemus tetraspis). We catalogued their acoustic repertoire and compared the calls recorded in captivity with 201 suspected wild O. tetraspis calls recorded in Gabon to determine whether the wild calls belonged to the same species. Captive and wild crocodiles produced the same four types of calls, not previously identified in other crocodylids. Short, low-frequency “drums” (31±12 Hz), longer, low-frequency “rumbles” (40 ± 14 Hz), as well as higher frequency “moos” (299 ± 133 Hz) and “gusts” (219 ± 108 Hz). Our results provide reference for species identification and support implementation of acoustic-based methods for African dwarf crocodile monitoring and conservation assessment. The data can further contribute to landscape-wide biodiversity monitoring and counter-poaching activities, as well as improving our understanding of crocodilian ecology and behaviour.
{"title":"The low-frequency vocal repertoire of adult African dwarf crocodiles","authors":"A. Staniewicz, G. McCabe, M. Holderied","doi":"10.1080/21564574.2023.2237035","DOIUrl":"https://doi.org/10.1080/21564574.2023.2237035","url":null,"abstract":"ABSTRACT Acoustic techniques are rapidly becoming powerful tools for species monitoring and biodiversity assessment. These methods can be particularly appropriate for forest-dwelling crocodiles which are difficult to survey visually. However, basic vocal-repertoire data is lacking for many of the poorly known species. Here, we used passive acoustic recorders to capture 97 spontaneous vocal signals from a pair of captive adult African dwarf crocodiles (Osteolaemus tetraspis). We catalogued their acoustic repertoire and compared the calls recorded in captivity with 201 suspected wild O. tetraspis calls recorded in Gabon to determine whether the wild calls belonged to the same species. Captive and wild crocodiles produced the same four types of calls, not previously identified in other crocodylids. Short, low-frequency “drums” (31±12 Hz), longer, low-frequency “rumbles” (40 ± 14 Hz), as well as higher frequency “moos” (299 ± 133 Hz) and “gusts” (219 ± 108 Hz). Our results provide reference for species identification and support implementation of acoustic-based methods for African dwarf crocodile monitoring and conservation assessment. The data can further contribute to landscape-wide biodiversity monitoring and counter-poaching activities, as well as improving our understanding of crocodilian ecology and behaviour.","PeriodicalId":49247,"journal":{"name":"African Journal of Herpetology","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2023-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46916252","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-04DOI: 10.1080/21564574.2023.2227189
P. Malonza
ABSTRACT A new threadsnake species from the family Leptotyphlopidae, Myriopholis mackayi sp. nov., is described from the Tsavo area in southeastern Kenya. Myriopholis mackayi sp. nov. is a member of the Myriopholis longicauda group on the basis of having a low number of middorsal scales, a discrete frontal shield, a rounded snout, a small anterior supralabial, a moderate posterior supralabial, semilunar cloacal shield, and pinkish colouration in life (brown dorsum and tan venter after preservation). The species is known from a xeric habitat at moderate elevation. It is highly recommended that future phylogenetic work is done to establish its taxonomic relations to other leptotyphlopids.
{"title":"A new species of threadsnake in the genus Myriopholis (Squamata: Scolecophidia: Leptotyplophidae) from southeastern Kenya","authors":"P. Malonza","doi":"10.1080/21564574.2023.2227189","DOIUrl":"https://doi.org/10.1080/21564574.2023.2227189","url":null,"abstract":"ABSTRACT A new threadsnake species from the family Leptotyphlopidae, Myriopholis mackayi sp. nov., is described from the Tsavo area in southeastern Kenya. Myriopholis mackayi sp. nov. is a member of the Myriopholis longicauda group on the basis of having a low number of middorsal scales, a discrete frontal shield, a rounded snout, a small anterior supralabial, a moderate posterior supralabial, semilunar cloacal shield, and pinkish colouration in life (brown dorsum and tan venter after preservation). The species is known from a xeric habitat at moderate elevation. It is highly recommended that future phylogenetic work is done to establish its taxonomic relations to other leptotyphlopids.","PeriodicalId":49247,"journal":{"name":"African Journal of Herpetology","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2023-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48819248","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-25DOI: 10.1080/21564574.2023.2191602
Jackson R. Phillips, Jens Reissig, Gary K. Nicolau
ABSTRACT Lungs are a prototypical trait of most tetrapods, but some amphibians have become secondarily lungless over evolutionary time. Anuran (frog) tadpoles offer an opportunity to examine lung loss from an evolutionary perspective, because there are many independent instances where lungs are not inflated until adulthood, and so are functionally lost. Lung loss is typically associated with living in fast-flowing streams, and so we examined larval lung development in the stream specialist family Heleophrynidae. We find that one genus, Hadromophryne Van Dijk, 2008, has large lungs as a tadpole, while the other genus, Heleophryne Sclater, 1898, has much smaller, stunted lung buds. We further speculate how this information changes our understanding of how the specialised torrent form has evolved in this specialised group.
肺是大多数四足动物的一个典型特征，但随着进化时间的推移，一些两栖动物已经成为继发性无肺动物。蛙类蝌蚪提供了一个从进化角度研究肺功能丧失的机会，因为有许多独立的例子表明，肺直到成年后才膨胀，因此功能丧失。肺损失通常与生活在湍急的溪流中有关，因此我们研究了溪流专家Heleophrynidae家族的幼虫肺发育。我们发现一个属，2008年出生的hadroophryne Van Dijk，有像蝌蚪一样大的肺，而另一个属，1898年出生的Heleophryne Sclater，肺芽要小得多，发育迟缓。我们进一步推测这些信息如何改变我们对特殊激流形式如何在这个特殊群体中进化的理解。
{"title":"Notes on lung development in South African ghost frogs (Anura: Heleophrynidae)","authors":"Jackson R. Phillips, Jens Reissig, Gary K. Nicolau","doi":"10.1080/21564574.2023.2191602","DOIUrl":"https://doi.org/10.1080/21564574.2023.2191602","url":null,"abstract":"ABSTRACT Lungs are a prototypical trait of most tetrapods, but some amphibians have become secondarily lungless over evolutionary time. Anuran (frog) tadpoles offer an opportunity to examine lung loss from an evolutionary perspective, because there are many independent instances where lungs are not inflated until adulthood, and so are functionally lost. Lung loss is typically associated with living in fast-flowing streams, and so we examined larval lung development in the stream specialist family Heleophrynidae. We find that one genus, Hadromophryne Van Dijk, 2008, has large lungs as a tadpole, while the other genus, Heleophryne Sclater, 1898, has much smaller, stunted lung buds. We further speculate how this information changes our understanding of how the specialised torrent form has evolved in this specialised group.","PeriodicalId":49247,"journal":{"name":"African Journal of Herpetology","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2023-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47267029","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-19DOI: 10.1080/21564574.2023.2191598
J. G. Larson, Breda M Zimkus
ABSTRACT We provide an expanded description of the tadpole of Amnirana albolabris (Ranidae) that includes external linear morphometrics and colouration across a developmental series ranging from Gosner stages 26–42. This description is based on material collected in Batéké Plateau National Park in south-eastern Gabon. The diurnal tadpoles are strikingly bright orange in life, a colouration that provides effective crypsis for the tannic waters in which they live. We also provide a comparative table for all of the described Amnirana tadpoles. The tadpole of A. albolabris can be identified in life by its unique colouration or in preservative by the seven prominent skin glands, assumed to contain defensive toxins.
{"title":"Detailed description and observations of the tadpole of Amnirana albolabris (Anura: Ranidae) from southeastern Gabon","authors":"J. G. Larson, Breda M Zimkus","doi":"10.1080/21564574.2023.2191598","DOIUrl":"https://doi.org/10.1080/21564574.2023.2191598","url":null,"abstract":"ABSTRACT We provide an expanded description of the tadpole of Amnirana albolabris (Ranidae) that includes external linear morphometrics and colouration across a developmental series ranging from Gosner stages 26–42. This description is based on material collected in Batéké Plateau National Park in south-eastern Gabon. The diurnal tadpoles are strikingly bright orange in life, a colouration that provides effective crypsis for the tannic waters in which they live. We also provide a comparative table for all of the described Amnirana tadpoles. The tadpole of A. albolabris can be identified in life by its unique colouration or in preservative by the seven prominent skin glands, assumed to contain defensive toxins.","PeriodicalId":49247,"journal":{"name":"African Journal of Herpetology","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2023-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44621824","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-11DOI: 10.1080/21564574.2023.2195775
B. Maritz
{"title":"A Complete Guide to the Snakes of Southern Africa, Third Edition","authors":"B. Maritz","doi":"10.1080/21564574.2023.2195775","DOIUrl":"https://doi.org/10.1080/21564574.2023.2195775","url":null,"abstract":"","PeriodicalId":49247,"journal":{"name":"African Journal of Herpetology","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2023-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47063572","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-13DOI: 10.1080/21564574.2023.2165547
M. Vences, Moritz Armerding, J. Köhler, F. Glaw
ABSTRACT A range-wide assessment of genetic variation in one mitochondrial (16S rRNA) and one nuclear-encoded (Rag-1) gene fragment of the widespread Madagascar frog Blommersia blommersae revealed the presence of up to 12 deep genetic lineages. Many of these differed by genetic distances >3% in the 16S gene. In the Ranomafana area in the southern central east of Madagascar, two mitochondrial lineages differing by 1.2–1.8% in 16S occurred in close syntopy across multiple sites. A phylogeny of representative samples based on multiple mitochondrial genes supported three main mitochondrial clades within B. blommersae, with lineages from the (i) north, (ii) north and northern central east, and (iii) southern central east, respectively. In addition, one lineage from Sainte Luce in the south-east was sister to all other species of Blommersia, and thus clearly not belonging to B. blommersae, to which it has been tentatively assigned previously. Except for the Sainte Luce population, most of the mitochondrial lineages did not show a concordant and consistent differentiation in Rag-1 and no obvious morphological differences were detected among the lineages. We therefore refrain from taxonomic conclusions for them at this time, although indications exist that the populations from the northern central east and southern central east may show certain differences in relative note duration of advertisement calls, which require further study. However, the Sainte Luce individuals were highly divergent in 16S (>10%) and Rag-1, phylogenetically isolated, and characterised by differences in colour pattern. This lineage represents the most evolutionarily divergent species of Blommersia known to date and is herein formally named and described as Blommersia dupreezi sp. nov.
{"title":"Genetic diversity of the mantellid frog Blommersia blommersae, and description of a new anuran species from south-eastern Madagascar","authors":"M. Vences, Moritz Armerding, J. Köhler, F. Glaw","doi":"10.1080/21564574.2023.2165547","DOIUrl":"https://doi.org/10.1080/21564574.2023.2165547","url":null,"abstract":"ABSTRACT A range-wide assessment of genetic variation in one mitochondrial (16S rRNA) and one nuclear-encoded (Rag-1) gene fragment of the widespread Madagascar frog Blommersia blommersae revealed the presence of up to 12 deep genetic lineages. Many of these differed by genetic distances >3% in the 16S gene. In the Ranomafana area in the southern central east of Madagascar, two mitochondrial lineages differing by 1.2–1.8% in 16S occurred in close syntopy across multiple sites. A phylogeny of representative samples based on multiple mitochondrial genes supported three main mitochondrial clades within B. blommersae, with lineages from the (i) north, (ii) north and northern central east, and (iii) southern central east, respectively. In addition, one lineage from Sainte Luce in the south-east was sister to all other species of Blommersia, and thus clearly not belonging to B. blommersae, to which it has been tentatively assigned previously. Except for the Sainte Luce population, most of the mitochondrial lineages did not show a concordant and consistent differentiation in Rag-1 and no obvious morphological differences were detected among the lineages. We therefore refrain from taxonomic conclusions for them at this time, although indications exist that the populations from the northern central east and southern central east may show certain differences in relative note duration of advertisement calls, which require further study. However, the Sainte Luce individuals were highly divergent in 16S (>10%) and Rag-1, phylogenetically isolated, and characterised by differences in colour pattern. This lineage represents the most evolutionarily divergent species of Blommersia known to date and is herein formally named and described as Blommersia dupreezi sp. nov.","PeriodicalId":49247,"journal":{"name":"African Journal of Herpetology","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2023-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48016639","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-03DOI: 10.1080/21564574.2022.2161015
Ferdi De Lange, E. Netherlands, L. D. du Preez
ABSTRACT The identity of adults and tadpoles of Ptychadena uzungwensis from the Soutpansberg range in northern South Africa was confirmed using a combination of morphological characters and molecular analysis. Detailed vocalisation analysis was made and used to complement existing species identification methods. This study confirms the presence of P. uzungwensis in South Africa. Sound recordings obtained by way of directional manual recordings were used to analyse call structure and call type while Passive Acoustic Monitoring with Song Meter® technology were used to survey circadian call patterns. Following confirmation of species identity, the detailed vocalisation analysis indicated a much more diverse repertoire than previously known. Three call types were observed with Type A consisting of two or three compressed notes; Type B consisting of a multi-note vocalisation, containing multiple pulses and notes produced in rapid succession; and Type C being a multi-note vocalisation consisting of rapidly released, randomly-spaced single notes. Detailed descriptions of call repertoires, including patterns and call types are useful for species identification and for use in comparison studies.
{"title":"Call repertoire of Ptychadena uzungwensis (Anura: Ptychadenidae) to complement molecular and morphological identification of the species from the Soutpansberg, South Africa.","authors":"Ferdi De Lange, E. Netherlands, L. D. du Preez","doi":"10.1080/21564574.2022.2161015","DOIUrl":"https://doi.org/10.1080/21564574.2022.2161015","url":null,"abstract":"ABSTRACT The identity of adults and tadpoles of Ptychadena uzungwensis from the Soutpansberg range in northern South Africa was confirmed using a combination of morphological characters and molecular analysis. Detailed vocalisation analysis was made and used to complement existing species identification methods. This study confirms the presence of P. uzungwensis in South Africa. Sound recordings obtained by way of directional manual recordings were used to analyse call structure and call type while Passive Acoustic Monitoring with Song Meter® technology were used to survey circadian call patterns. Following confirmation of species identity, the detailed vocalisation analysis indicated a much more diverse repertoire than previously known. Three call types were observed with Type A consisting of two or three compressed notes; Type B consisting of a multi-note vocalisation, containing multiple pulses and notes produced in rapid succession; and Type C being a multi-note vocalisation consisting of rapidly released, randomly-spaced single notes. Detailed descriptions of call repertoires, including patterns and call types are useful for species identification and for use in comparison studies.","PeriodicalId":49247,"journal":{"name":"African Journal of Herpetology","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2023-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48719677","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-27DOI: 10.1080/21564574.2022.2115154
Thabo I Hlatshwayo, E. Stam, Wendy J. Collinson-Jonker, Abeda Dawood
ABSTRACT Increasing linear infrastructure development often impacts habitats and wildlife negatively. Roads, in particular, have numerous threats to wildlife with the most noticeable direct impact being roadkill, and this requires urgent conservation interventions. To assess amphibian roadkill, driven surveys were conducted on three regional roads around the western Soutpansberg in the Vhembe Biosphere Reserve, an important area for biodiversity conservation in South Africa. Six habitat types were identified along the monitored road stretches and their influence on the occurrence of amphibian roadkill was determined. The results comprised an inventory of 248 roadkill specimens, belonging to eight species and six families, and one unidentified specimen. Roadkill was strongly influenced by season, with the greatest roadkill rate recorded in the early wet season (0.051 roadkill km–1 day–1) compared to the late wet season (0.019 roadkill km–1 day–1). Amphibian roadkill patterns were related to roadside habitat. Of the roadside habitat types identified, road sections adjacent to waterbodies had the highest number of roadkill, followed by road sections closer to open savanna bushland. Roadkill frequency was low in areas that were partly located in human modified habitats (residential and agricultural areas) but highest in natural landscapes (near waterbodies and savanna bushland). The study provides baseline data that confirms the potential threat of roads and their users on the persistence of amphibians in the Vhembe Biosphere Reserve and presents the first systematic inventory of amphibian roadkill in the western Soutpansberg, South Africa.
{"title":"An inventory of amphibian roadkill in the western Soutpansberg, Limpopo province, South Africa","authors":"Thabo I Hlatshwayo, E. Stam, Wendy J. Collinson-Jonker, Abeda Dawood","doi":"10.1080/21564574.2022.2115154","DOIUrl":"https://doi.org/10.1080/21564574.2022.2115154","url":null,"abstract":"ABSTRACT Increasing linear infrastructure development often impacts habitats and wildlife negatively. Roads, in particular, have numerous threats to wildlife with the most noticeable direct impact being roadkill, and this requires urgent conservation interventions. To assess amphibian roadkill, driven surveys were conducted on three regional roads around the western Soutpansberg in the Vhembe Biosphere Reserve, an important area for biodiversity conservation in South Africa. Six habitat types were identified along the monitored road stretches and their influence on the occurrence of amphibian roadkill was determined. The results comprised an inventory of 248 roadkill specimens, belonging to eight species and six families, and one unidentified specimen. Roadkill was strongly influenced by season, with the greatest roadkill rate recorded in the early wet season (0.051 roadkill km–1 day–1) compared to the late wet season (0.019 roadkill km–1 day–1). Amphibian roadkill patterns were related to roadside habitat. Of the roadside habitat types identified, road sections adjacent to waterbodies had the highest number of roadkill, followed by road sections closer to open savanna bushland. Roadkill frequency was low in areas that were partly located in human modified habitats (residential and agricultural areas) but highest in natural landscapes (near waterbodies and savanna bushland). The study provides baseline data that confirms the potential threat of roads and their users on the persistence of amphibians in the Vhembe Biosphere Reserve and presents the first systematic inventory of amphibian roadkill in the western Soutpansberg, South Africa.","PeriodicalId":49247,"journal":{"name":"African Journal of Herpetology","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2022-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44982177","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-03DOI: 10.1080/21564574.2022.2098392
K. Tolley
ABSTRACT Arboreal chameleons must navigate a complex, three-dimensional landscape consisting of trees, bushes and/or grasses of various sizes. This complexity equates to the microhabitat of chameleons, that is, the branches upon which they perch and through which they move. Therefore, chameleons rely on their ability to grip perches available to them, and this is evident by their specialised adaptations such as their prehensile tail and their grasping hands and feet. To date, ecological studies of chameleons have relied on gathering data on perch use only at night because locating chameleons during the daytime is extremely difficult. However, the night-time perch represents the sleeping perch of individuals, and this is not necessarily reflective of overall diel perch use. Many other arboreal reptiles are constrained to using thin perches at night, but by day their microhabitat is more variable, using thicker branches, limbs or tree trunks. To assess whether this well-entrenched paradigm (night-time perch use being constrained to thin perches) also extends to fully arboreal chameleons, daytime and night-time perch diameters were measured for the Cape Dwarf Chameleon, Bradypodion pumilum, and were compared using analyses of variance statistical approaches. Neither perch diameters nor variance in perch diameters differed between the two photoperiods, and the variance in diameters of perches used was remarkably high. Despite this variance, there was a significant, positive relationship between body size and the diameter of perches used. Unlike other reptiles, the results show that for B. pumilum the night-time perch use is not different than diurnal perch use, and there appears to be a fairly wide range of perches used by chameleons of a given body size over both photoperiods. Nevertheless, the positive trend for chameleons of larger body sizes to choose larger perches than smaller chameleons implies that there are some upper and lower constraints for the diameters of perches used, possibly relating to their ability to effectively grip a range of perch sizes.
{"title":"Is it like night and day? Nocturnal versus diurnal perch use by dwarf chameleons (Bradypodion pumilum)","authors":"K. Tolley","doi":"10.1080/21564574.2022.2098392","DOIUrl":"https://doi.org/10.1080/21564574.2022.2098392","url":null,"abstract":"ABSTRACT Arboreal chameleons must navigate a complex, three-dimensional landscape consisting of trees, bushes and/or grasses of various sizes. This complexity equates to the microhabitat of chameleons, that is, the branches upon which they perch and through which they move. Therefore, chameleons rely on their ability to grip perches available to them, and this is evident by their specialised adaptations such as their prehensile tail and their grasping hands and feet. To date, ecological studies of chameleons have relied on gathering data on perch use only at night because locating chameleons during the daytime is extremely difficult. However, the night-time perch represents the sleeping perch of individuals, and this is not necessarily reflective of overall diel perch use. Many other arboreal reptiles are constrained to using thin perches at night, but by day their microhabitat is more variable, using thicker branches, limbs or tree trunks. To assess whether this well-entrenched paradigm (night-time perch use being constrained to thin perches) also extends to fully arboreal chameleons, daytime and night-time perch diameters were measured for the Cape Dwarf Chameleon, Bradypodion pumilum, and were compared using analyses of variance statistical approaches. Neither perch diameters nor variance in perch diameters differed between the two photoperiods, and the variance in diameters of perches used was remarkably high. Despite this variance, there was a significant, positive relationship between body size and the diameter of perches used. Unlike other reptiles, the results show that for B. pumilum the night-time perch use is not different than diurnal perch use, and there appears to be a fairly wide range of perches used by chameleons of a given body size over both photoperiods. Nevertheless, the positive trend for chameleons of larger body sizes to choose larger perches than smaller chameleons implies that there are some upper and lower constraints for the diameters of perches used, possibly relating to their ability to effectively grip a range of perch sizes.","PeriodicalId":49247,"journal":{"name":"African Journal of Herpetology","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2022-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44051452","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-08-18DOI: 10.1080/21564574.2022.2098393
S. Welman, I. Ibarzabal
ABSTRACT Temperature profoundly influences the functioning of ectotherms and understanding the thermal biology of invasive species affords valuable insights regarding the suitability of different habitats. Yet, this remains an understudied aspect in the field of invasion biology. Here, we investigated the thermal physiology of the highly invasive Tropical House Gecko (Hemidactylus mabouia) in a coastal region of South Africa. The study site is near to the southernmost extent of the species’ distribution and we expected the physiology of individuals at the study site to differ compared to that of individuals inhabiting tropical regions. Relative to tropical geckos, we observed a decrease of 3.4°C in preferred body temperature (Tpref) to 24.0 °C, which was likely driven by selection for improved functioning within the cooler temperate climate. However, the lower (CTmin) and upper (CTmax) critical thermal limits were higher in geckos at the study site. CTmin was similar between sexes at 11.9 °C, whereas males had a higher CTmax by ≈ 1.9 °C reaching 39.7 °C. A broader tolerance range is typical of a highly variable climate, and we presume that the increase in CTmax allows geckos to better cope with occasional high temperatures. Further, sex-specific differences are uncommon in reptiles, but our study supports claims of improved heat tolerance in male geckos, argued to be related to their aggressive and territorial behaviour. The results also support claims that tropical geckos are more adaptable than previously thought, allowing them to invade new areas. Thereafter, their aggressive behaviour, dietary flexibility and year-round activity likely provides house geckos with a competitive advantage over some native reptiles.
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