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Philip C. Withers - One of the best experts on this subject based on the ideXlab platform.
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Higher than predicted endurance for juvenile goannas (Varanidae; Varanus)
Journal of the Royal Society of Western Australia, 2008Co-Authors: Christofer J. Clemente, Philip C. Withers, Graham G. ThompsonAbstract:Endurance of juvenile Western Australian varanid lizards was compared with that of conspecific adults. Among adults, endurance generally increased intra-specifically with increasing body size. However, juvenile varanids have a higher than expected endurance. Possible causes for this heightened endurance are discussed, and probably result from a relatively high maximal metabolic rate, as has been previously described for juvenile varanids. Origins of relatively high metabolic rates are unknown, but may be caused by greater oxygen affinity of juvenile haemoglobin when compared to adult conspecifics. V. gouldii 15 0.01 0.763 0.56 0.001 (ex. juv.) 13 0.29 0.054 0.40 0.022 V. mertensi 11 0.06 0.469 0.37 0.046 (ex. juv.) 8 0.27 0.190 0.53 0.039 V. mitchelli 7 0.48 0.084 0.19 0.325 (ex. juv.) 6 0.52 0.106 0.72 0.034 V. panoptes 12 0.18 0.174 0.25 0.095 (ex. juv.) 10 0.50 0.021 0.31 0.095
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Metabolic rate of neonate goannas (Squamata: Varanidae)
Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, 1998Co-Authors: Graham G. Thompson, Philip C. WithersAbstract:At 35°C, the standard and maximal metabolic rates for neonates of four species of goannas (Varanus brevicauda, V. eremius, V. tristis and V. gouldii) are consistently higher than predicted by intraspecific equations for adults. However, this is difficult to demonstrate statistically. The consequence of this is that the data for neonates probably should be excluded from the data used to establish intraspecific allometric regression equations for adults. From an interspecific perspective, neonate V. mertensi have a lower standard (0.16 ml O2 g−1 per h) and maximal (1.18 ml g−1 per h) metabolic rate than neonate V. brevicauda (0.22 ml g−1 per h), V. eremius (0.28 and 2.94 ml g−1 per h, respectively), V. tristis (0.33 and 3.43 ml g−1 per h) and V. gouldii (0.29 and 5.24 ml g−1 per h) at 35°C. Such interspecies differences need to be accounted for in interspecific allometric analysis.
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comparative morphology of western australian varanid lizards squamata Varanidae
Journal of Morphology, 1997Co-Authors: Graham G. Thompson, Philip C. WithersAbstract:Varanid lizards, which vary considerably in body mass both interspecifically and intraspecifically, are generally considered to be morpho- logically similar. However, significant and non-isometric variation in the relative appendage dimensions for 17 species of Western Australian goannas suggest that these lizards are not morphologically conservative. The first and second canonical variates clearly distinguish the two subgeneral Odatria and Varanus, and species are generally sexually dimorphic. The morphological variation observed among these 17 species of goanna is associated with foraging mode and ecology. However, no single or small group of morphological dimensions discriminates phylogenetic groups, sexes, or ecological groups, and body size is an important component in these analyses. J. Morphol. 233:127-152, 1997. r 1997 Wiley-Liss, Inc. The morphology of a lizard is largely deter- mined by its ancestry, ecological niche, body size, and development (Peters, '83; Calder, '84; Schmidt-Nielsen, '84). In addition, some species of reptile are also sexually dimorphic in body shape or size (Vitt and Cooper, '85; Shine, '92). The lizard family Varanidae pro- vides an excellent opportunity to study the interrelationships of body size and shape with ecology. Varanidae consists of only a single extant genus, Varanus, and contains about 45 species. The mass range ofVaranus is more than three orders of magnitude, ranging from <20g(V. brevicauda; personal observations) to <54 kg (V. komodoensis; Auffenberg, '81). There are a variety of eco- logical specializations, including tree climb- ing, rock scampering, and swimming. Never- theless, a numbers of authors (Shine, '86; Greer, '89; King and Green, '93b; Pianka, '95) have suggested that their body form is conservative compared with the variation in other families of lizards. The genus Varanus is considered to be monophyletic (Baverstock et al., '93), and thus comparison of varanid species is not complicated by higher level phylogenetic dif- ferences. Baverstock et al. ('93) summarized the phylogeny ofVaranusand suggested four clades based on immunogenetic and karyo- typic studies: an Asian clade, an African clade, anAustralian/S.E.Asian clade of large goannas (subgenus Varanus), and a clade of Australian pygmy goanna (subgenus Odatria). Nearly all of the members of the Varanus clade (except V. komodoensis and V. salvadorii) and all of the members of the Odatria clade are found in Australia; V. er- emiusprobably belongs to theOdatriagroup, although it was initially placed outside these clades (Pianka, '95). Morphometric examina- tion of the 18 species/subspecies of goanna found in WesternAustralia allows a compari- son of theVaranusandOdatriasubgenera. Others (e.g., Snyder, '54; Collette, '61; Ball- inger, '73; Laerm, '74; Moermond, '79; Pianka, '86; Losos, '90a-c; Miles, '94) have suggested that there are morphological char- acteristics that can be associated with habi- tat and performance traits. Pianka ('68, '69, '70a,b, '71, '82, '86, '94) provides most of the limited ecological and behavioral data, and some additional general information on their ecology is provided by Storr et al. ('83) and Wilson and Knowles ('92). Greer ('89) groups all Australian goannas into four broad eco- logical categories (ground, rocky outcrop, ar- boreal, and aquatic/arboreal). The only obvi-
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Comparative morphology of Western Australian varanid lizards (Squamata: Varanidae)
Journal of morphology, 1997Co-Authors: Graham G. Thompson, Philip C. WithersAbstract:Varanid lizards, which vary considerably in body mass both interspecifically and intraspecifically, are generally considered to be morpho- logically similar. However, significant and non-isometric variation in the relative appendage dimensions for 17 species of Western Australian goannas suggest that these lizards are not morphologically conservative. The first and second canonical variates clearly distinguish the two subgeneral Odatria and Varanus, and species are generally sexually dimorphic. The morphological variation observed among these 17 species of goanna is associated with foraging mode and ecology. However, no single or small group of morphological dimensions discriminates phylogenetic groups, sexes, or ecological groups, and body size is an important component in these analyses. J. Morphol. 233:127-152, 1997. r 1997 Wiley-Liss, Inc. The morphology of a lizard is largely deter- mined by its ancestry, ecological niche, body size, and development (Peters, '83; Calder, '84; Schmidt-Nielsen, '84). In addition, some species of reptile are also sexually dimorphic in body shape or size (Vitt and Cooper, '85; Shine, '92). The lizard family Varanidae pro- vides an excellent opportunity to study the interrelationships of body size and shape with ecology. Varanidae consists of only a single extant genus, Varanus, and contains about 45 species. The mass range ofVaranus is more than three orders of magnitude, ranging from
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Standard and Maximal Metabolic Rates of Goannas (Squamata: Varanidae)
Physiological zoology, 1997Co-Authors: Graham G. Thompson, Philip C. WithersAbstract:Standard metabolic rate and maximal metabolic rate during forced exercise are examined for nine species of goanna (genus Varanus), with body mass varying from 10 to 3,750 g. At 35°C, the common pooled mass exponent for standard metabolic rate is 0.97 and at 25°C it is 0.89, with considerable variation between species (0.43-1.20). Standard metabolic rate at 35°C scales interspecifically with body $mass^{0.92}$ and at 25°C with body $mass^{087}$. The $Q_{10}$ for standard metabolic rate is approximately 2.5 between 25° and 35°C. At 35°C, maximal metabolic rate scales intraspecifically with body $mass^{0.79}$ and scales interspecifically with body $mass^{0.72}$. Factorial metabolic scope ranges from nine for the larger species to 35 for the smaller species; it scales with body $mass^{-0.99}$ at 35°C. The maximal metabolic rate of 6.36 mL O₂ g⁻¹ h⁻¹ for Varanus caudolineatus is the highest recorded for any squamate. Variations from the interspecific regression line appear to have some ecological significance....
Graham G. Thompson - One of the best experts on this subject based on the ideXlab platform.
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Higher than predicted endurance for juvenile goannas (Varanidae; Varanus)
Journal of the Royal Society of Western Australia, 2008Co-Authors: Christofer J. Clemente, Philip C. Withers, Graham G. ThompsonAbstract:Endurance of juvenile Western Australian varanid lizards was compared with that of conspecific adults. Among adults, endurance generally increased intra-specifically with increasing body size. However, juvenile varanids have a higher than expected endurance. Possible causes for this heightened endurance are discussed, and probably result from a relatively high maximal metabolic rate, as has been previously described for juvenile varanids. Origins of relatively high metabolic rates are unknown, but may be caused by greater oxygen affinity of juvenile haemoglobin when compared to adult conspecifics. V. gouldii 15 0.01 0.763 0.56 0.001 (ex. juv.) 13 0.29 0.054 0.40 0.022 V. mertensi 11 0.06 0.469 0.37 0.046 (ex. juv.) 8 0.27 0.190 0.53 0.039 V. mitchelli 7 0.48 0.084 0.19 0.325 (ex. juv.) 6 0.52 0.106 0.72 0.034 V. panoptes 12 0.18 0.174 0.25 0.095 (ex. juv.) 10 0.50 0.021 0.31 0.095
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Allometry of Clutch and Neonate Sizes in Monitor Lizards (Varanidae: Varanus)
Copeia, 2001Co-Authors: Graham G. Thompson, Eric R. PiankaAbstract:Abstract This paper analyzes data from the published literature with the addition of some new information to explore the relationship between varanid body size and reproductive biology. Incubation time for varanid eggs is positively correlated with egg mass, neonate snout–vent length (SVL), and maximum adult snout–vent length (SVLmax). Incubation period of heavier eggs is proportionally less than for smaller eggs at 30 C. SVLmax is positively correlated with egg mass, clutch size, clutch mass, neonate body mass, and neonate SVL. Neonates of larger species have longer SVL but are smaller as a proportion of SVLmax than for smaller species. Clutch sizes are larger and more variable for larger species; however, clutch sizes for larger species relative to SVLmax are smaller than for smaller species. The intraspecific influence of maternal SVL on clutch size is greater than the interspecific influence of SVLmax on clutch size. These results suggest there are greater fitness advantages for smaller species having...
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Reproductive ecology of the black-headed goanna Varanus tristis (Squamata: Varanidae)
Journal of the Royal Society of Western Australia, 1999Co-Authors: Graham G. Thompson, E. R. PiankaAbstract:The black-headed goanna, Varanus tristis, oviposits in October and November in the western Great Victoria Desert; the eggs are layed in a hole that the female digs in the ground. Neonates hatch toward the end of summer. Body colour and pattern of neonate V. tristis differ appreciably in the western Great Victoria Desert from adults, and changes to the adult pattern after a couple of months. Clutch size for V. tristis is best predicted from body mass, although there is also a significant relationship between clutch size and snout-to-vent length. An inter-specific regression equation for the Odatria subgenus is a much more accurate predictor of clutch size for V. tristis than a regression equation that includes data for goannas of other subgenera. Fat bodies of males decrease in size during December and January then increase during February and March; they are largest during September and October. Combined testis length decrease from appropriately 11% of snout-to-vent length (SVL) during the breeding season in early summer to 5% of SVL in February.
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Metabolic rate of neonate goannas (Squamata: Varanidae)
Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, 1998Co-Authors: Graham G. Thompson, Philip C. WithersAbstract:At 35°C, the standard and maximal metabolic rates for neonates of four species of goannas (Varanus brevicauda, V. eremius, V. tristis and V. gouldii) are consistently higher than predicted by intraspecific equations for adults. However, this is difficult to demonstrate statistically. The consequence of this is that the data for neonates probably should be excluded from the data used to establish intraspecific allometric regression equations for adults. From an interspecific perspective, neonate V. mertensi have a lower standard (0.16 ml O2 g−1 per h) and maximal (1.18 ml g−1 per h) metabolic rate than neonate V. brevicauda (0.22 ml g−1 per h), V. eremius (0.28 and 2.94 ml g−1 per h, respectively), V. tristis (0.33 and 3.43 ml g−1 per h) and V. gouldii (0.29 and 5.24 ml g−1 per h) at 35°C. Such interspecies differences need to be accounted for in interspecific allometric analysis.
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comparative morphology of western australian varanid lizards squamata Varanidae
Journal of Morphology, 1997Co-Authors: Graham G. Thompson, Philip C. WithersAbstract:Varanid lizards, which vary considerably in body mass both interspecifically and intraspecifically, are generally considered to be morpho- logically similar. However, significant and non-isometric variation in the relative appendage dimensions for 17 species of Western Australian goannas suggest that these lizards are not morphologically conservative. The first and second canonical variates clearly distinguish the two subgeneral Odatria and Varanus, and species are generally sexually dimorphic. The morphological variation observed among these 17 species of goanna is associated with foraging mode and ecology. However, no single or small group of morphological dimensions discriminates phylogenetic groups, sexes, or ecological groups, and body size is an important component in these analyses. J. Morphol. 233:127-152, 1997. r 1997 Wiley-Liss, Inc. The morphology of a lizard is largely deter- mined by its ancestry, ecological niche, body size, and development (Peters, '83; Calder, '84; Schmidt-Nielsen, '84). In addition, some species of reptile are also sexually dimorphic in body shape or size (Vitt and Cooper, '85; Shine, '92). The lizard family Varanidae pro- vides an excellent opportunity to study the interrelationships of body size and shape with ecology. Varanidae consists of only a single extant genus, Varanus, and contains about 45 species. The mass range ofVaranus is more than three orders of magnitude, ranging from <20g(V. brevicauda; personal observations) to <54 kg (V. komodoensis; Auffenberg, '81). There are a variety of eco- logical specializations, including tree climb- ing, rock scampering, and swimming. Never- theless, a numbers of authors (Shine, '86; Greer, '89; King and Green, '93b; Pianka, '95) have suggested that their body form is conservative compared with the variation in other families of lizards. The genus Varanus is considered to be monophyletic (Baverstock et al., '93), and thus comparison of varanid species is not complicated by higher level phylogenetic dif- ferences. Baverstock et al. ('93) summarized the phylogeny ofVaranusand suggested four clades based on immunogenetic and karyo- typic studies: an Asian clade, an African clade, anAustralian/S.E.Asian clade of large goannas (subgenus Varanus), and a clade of Australian pygmy goanna (subgenus Odatria). Nearly all of the members of the Varanus clade (except V. komodoensis and V. salvadorii) and all of the members of the Odatria clade are found in Australia; V. er- emiusprobably belongs to theOdatriagroup, although it was initially placed outside these clades (Pianka, '95). Morphometric examina- tion of the 18 species/subspecies of goanna found in WesternAustralia allows a compari- son of theVaranusandOdatriasubgenera. Others (e.g., Snyder, '54; Collette, '61; Ball- inger, '73; Laerm, '74; Moermond, '79; Pianka, '86; Losos, '90a-c; Miles, '94) have suggested that there are morphological char- acteristics that can be associated with habi- tat and performance traits. Pianka ('68, '69, '70a,b, '71, '82, '86, '94) provides most of the limited ecological and behavioral data, and some additional general information on their ecology is provided by Storr et al. ('83) and Wilson and Knowles ('92). Greer ('89) groups all Australian goannas into four broad eco- logical categories (ground, rocky outcrop, ar- boreal, and aquatic/arboreal). The only obvi-
Nico J. Smit - One of the best experts on this subject based on the ideXlab platform.
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Redescription, molecular characterisation and taxonomic re-evaluation of a unique African monitor lizard haemogregarine Karyolysus paradoxa (Dias, 1954) n. comb. (Karyolysidae)
Parasites & vectors, 2016Co-Authors: Courtney A. Cook, Edward C. Netherlands, Nico J. SmitAbstract:Background Within the African monitor lizard family Varanidae, two haemogregarine genera have been reported. These comprise five species of Hepatozoon Miller, 1908 and a species of Haemogregarina Danilewsky, 1885. Even though other haemogregarine genera such as Hemolivia Petit, Landau, Baccam & Lainson, 1990 and Karyolysus Labbe, 1894 have been reported parasitising other lizard families, these have not been found infecting the Varanidae. The genus Karyolysus has to date been formally described and named only from lizards of the family Lacertidae and to the authors’ knowledge, this includes only nine species. Molecular characterisation using fragments of the 18S gene has only recently been completed for but two of these species. To date, three Hepatozoon species are known from southern African varanids, one of these Hepatozoon paradoxa (Dias, 1954) shares morphological characteristics alike to species of the family Karyolysidae. Thus, this study aimed to morphologically redescribe and characterise H. paradoxa molecularly, so as to determine its taxonomic placement.
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Redescription, molecular characterisation and taxonomic re-evaluation of a unique African monitor lizard haemogregarine Karyolysus paradoxa (Dias, 1954) n. comb. (Karyolysidae)
Parasites & Vectors, 2016Co-Authors: Courtney A. Cook, Edward C. Netherlands, Nico J. SmitAbstract:Background Within the African monitor lizard family Varanidae, two haemogregarine genera have been reported. These comprise five species of Hepatozoon Miller, 1908 and a species of Haemogregarina Danilewsky, 1885. Even though other haemogregarine genera such as Hemolivia Petit, Landau, Baccam & Lainson, 1990 and Karyolysus Labbé, 1894 have been reported parasitising other lizard families, these have not been found infecting the Varanidae. The genus Karyolysus has to date been formally described and named only from lizards of the family Lacertidae and to the authors’ knowledge, this includes only nine species. Molecular characterisation using fragments of the 18S gene has only recently been completed for but two of these species. To date, three Hepatozoon species are known from southern African varanids, one of these Hepatozoon paradoxa (Dias, 1954) shares morphological characteristics alike to species of the family Karyolysidae. Thus, this study aimed to morphologically redescribe and characterise H. paradoxa molecularly, so as to determine its taxonomic placement. Methods Specimens of Varanus albigularis albigularis Daudin, 1802 (Rock monitor) and Varanus niloticus (Linnaeus in Hasselquist, 1762) (Nile monitor) were collected from the Ndumo Game Reserve, South Africa. Upon capture animals were examined for haematophagous arthropods. Blood was collected, thin blood smears prepared, stained with Giemsa, screened and micrographs of parasites captured. Haemogregarine morphometric data were compared with the data for named haemogregarines of African varanids. Primer set HepF300 and HepR900 was employed to target a fragment of the 18S rRNA gene and resulting sequences compared with other known haemogregarine sequences selected from the GenBank database. Results Hepatozoon paradoxa was identified infecting two out of eight (25 %) V. a. albigularis and a single (100 %) V. niloticus examined. Phylogenetic analyses revealed that H. paradoxa clustered with the ‘ Karyolysus ’ clade, and not with those of reptilian Hepatozoon spp. Conclusions In addition to this being the first morphological and molecular characterisation of a haemogregarine within the African Varanidae, it is the first report of a species of Karyolysus infecting the monitor lizard family. Furthermore, this constitutes now only the third described and named Karyolysus species for which there is a nucleotide sequence available.
Courtney A. Cook - One of the best experts on this subject based on the ideXlab platform.
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Redescription, molecular characterisation and taxonomic re-evaluation of a unique African monitor lizard haemogregarine Karyolysus paradoxa (Dias, 1954) n. comb. (Karyolysidae)
Parasites & vectors, 2016Co-Authors: Courtney A. Cook, Edward C. Netherlands, Nico J. SmitAbstract:Background Within the African monitor lizard family Varanidae, two haemogregarine genera have been reported. These comprise five species of Hepatozoon Miller, 1908 and a species of Haemogregarina Danilewsky, 1885. Even though other haemogregarine genera such as Hemolivia Petit, Landau, Baccam & Lainson, 1990 and Karyolysus Labbe, 1894 have been reported parasitising other lizard families, these have not been found infecting the Varanidae. The genus Karyolysus has to date been formally described and named only from lizards of the family Lacertidae and to the authors’ knowledge, this includes only nine species. Molecular characterisation using fragments of the 18S gene has only recently been completed for but two of these species. To date, three Hepatozoon species are known from southern African varanids, one of these Hepatozoon paradoxa (Dias, 1954) shares morphological characteristics alike to species of the family Karyolysidae. Thus, this study aimed to morphologically redescribe and characterise H. paradoxa molecularly, so as to determine its taxonomic placement.
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Redescription, molecular characterisation and taxonomic re-evaluation of a unique African monitor lizard haemogregarine Karyolysus paradoxa (Dias, 1954) n. comb. (Karyolysidae)
Parasites & Vectors, 2016Co-Authors: Courtney A. Cook, Edward C. Netherlands, Nico J. SmitAbstract:Background Within the African monitor lizard family Varanidae, two haemogregarine genera have been reported. These comprise five species of Hepatozoon Miller, 1908 and a species of Haemogregarina Danilewsky, 1885. Even though other haemogregarine genera such as Hemolivia Petit, Landau, Baccam & Lainson, 1990 and Karyolysus Labbé, 1894 have been reported parasitising other lizard families, these have not been found infecting the Varanidae. The genus Karyolysus has to date been formally described and named only from lizards of the family Lacertidae and to the authors’ knowledge, this includes only nine species. Molecular characterisation using fragments of the 18S gene has only recently been completed for but two of these species. To date, three Hepatozoon species are known from southern African varanids, one of these Hepatozoon paradoxa (Dias, 1954) shares morphological characteristics alike to species of the family Karyolysidae. Thus, this study aimed to morphologically redescribe and characterise H. paradoxa molecularly, so as to determine its taxonomic placement. Methods Specimens of Varanus albigularis albigularis Daudin, 1802 (Rock monitor) and Varanus niloticus (Linnaeus in Hasselquist, 1762) (Nile monitor) were collected from the Ndumo Game Reserve, South Africa. Upon capture animals were examined for haematophagous arthropods. Blood was collected, thin blood smears prepared, stained with Giemsa, screened and micrographs of parasites captured. Haemogregarine morphometric data were compared with the data for named haemogregarines of African varanids. Primer set HepF300 and HepR900 was employed to target a fragment of the 18S rRNA gene and resulting sequences compared with other known haemogregarine sequences selected from the GenBank database. Results Hepatozoon paradoxa was identified infecting two out of eight (25 %) V. a. albigularis and a single (100 %) V. niloticus examined. Phylogenetic analyses revealed that H. paradoxa clustered with the ‘ Karyolysus ’ clade, and not with those of reptilian Hepatozoon spp. Conclusions In addition to this being the first morphological and molecular characterisation of a haemogregarine within the African Varanidae, it is the first report of a species of Karyolysus infecting the monitor lizard family. Furthermore, this constitutes now only the third described and named Karyolysus species for which there is a nucleotide sequence available.
Jack L. Conrad - One of the best experts on this subject based on the ideXlab platform.
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Skeletons of the Little-Known Palawan Monitor, Varanus palawanensis (Squamata: Varanidae)
Journal of Herpetology, 2015Co-Authors: Jack L. ConradAbstract:Abstract Varanus (Soterosaurus) monitors recently received increased scrutiny from herpetologists, resulting in identification of previously unrecognized morphologic and genetic diversity. These advances rendered Varanus salvator salvator as one of the most narrowly distributed monitors, because most populations are reassigned to existing or newly identified species. No diagnostic skeletal characters are known for those species. Two skeletonized specimens of the recently named Varanus palawanensis are in the collection of the U.S. National Museum of Natural History, but are labeled V. salvator. Here, I offer some observations on those skeletons, make comparisons with some other Varanus(Soterosaurus) monitors, and update the diagnosis of the species with some probable osteological autapomorphies. Varanus palawanensis differs from other Varanus (Soterosaurus) in possessing a unique combination of character states. The premaxilla extends to the level of the frontal, the frontal and parietal lack dermal sculp...
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Earliest Example of a Giant Monitor Lizard (Varanus, Varanidae, Squamata)
PloS one, 2012Co-Authors: Jack L. Conrad, Ana M. Balcarcel, Carl MehlingAbstract:Background Varanidae is a clade of tiny ( 600 mm PCL) lizards first appearing in the Cretaceous. True monitor lizards (Varanus) are known from diagnostic remains beginning in the early Miocene (Varanus rusingensis), although extremely fragmentary remains have been suggested as indicating earlier Varanus. The paleobiogeographic history of Varanus and timing for origin of its gigantism remain uncertain. Methodology/Principal Findings A new Varanus from the Mytilini Formation (Turolian, Miocene) of Samos, Greece is described. The holotype consists of a partial skull roof, right side of a braincase, partial posterior mandible, fragment of clavicle, and parts of six vertebrae. A cladistic analysis including 83 taxa coded for 5733 molecular and 489 morphological characters (71 previously unincluded) demonstrates that the new fossil is a nested member of an otherwise exclusively East Asian Varanus clade. The new species is the earliest-known giant (>600 mm PCL) terrestrial lizard. Importantly, this species co-existed with a diverse continental mammalian fauna. Conclusions/Significance The new monitor is larger (longer) than 99% of known fossil and living lizards. Varanus includes, by far, the largest limbed squamates today. The only extant non-snake squamates that approach monitors in maximum size are the glass-snake Pseudopus and the worm-lizard Amphisbaena. Mosasauroids were larger, but exclusively marine, and occurred only during the Late Cretaceous. Large, extant, non-Varanus, lizards are limbless and/or largely isolated from mammalian competitors. By contrast, our new Varanus achieved gigantism in a continental environment populated by diverse eutherian mammal competitors.
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SIZES OF EXTANT Varanidae.
2012Co-Authors: Jack L. Conrad, Ana M. Balcarcel, Carl M. MehlingAbstract:Lengths of 52 species of Varanidae (51 species of Varanus and Lanthanotus borneensis) based on published data [21], [79]. These data were used to reconstruct the lineage sizes in Figure 5. Note that not all measurements and/or data are available for all included species. Abbreviations: SVL, snout-to-vent length of the animal; TL, total length of the animal (snout to tail tip); approx, approximate length based on published data [21]; Auffenberg approx, approximate dimensions based on data presented for wild-caught specimens in Auffenberg's study on Komodo Dragons [79]; F, female; holotype/type/voucher, measurements based on the type specimen—these data are usually reported in the case of species wherein there are few available specimens; M, male; max, reported maximum measurement; max field, reported maximum measurement of wild-caught specimens—these data are usually included when the species in question is popular in the pet trade.
