Seasonal Variation in Fat Body Weights of the Mexican High Elevation Lizard Sceloporus grammicus microlepidotus

Guillette, Louis J.; Casas-Andreu, Gustavo

doi:10.2307/1563443

Cited by 39 publications

(13 citation statements)

References 16 publications

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“…A second collection of lizards made in February 1991 (not used in this study) consisted entirely of adults, with no males showing testicular activity, and all females were gravid with moderately to well-developed embryos. The reproductive cycles of these races thus correspond to those of populations studied in other localities, and these without exception show that testicular and ovarian activities are synchronized to autumn mating followed by spring parturition (Axtell & Axtell 1970;Guillette & Casas-Andreu 1980, 1981Ortega & Quad 10 Barbault 1984; Ortega 1986). The June-July collection used in this study therefore conforms unambiguously to a 'census-before-mating' scenario.…”

Section: S Fa Tis Tical Analysessupporting

confidence: 55%

Cytonuclear genetic structure of a hybrid zone in lizards of the Sceloporus grammicus complex (Sauria, Phrynosomatidae)

Sites¹,

Basten²,

Asmussen³

1996

Mol Ecol

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Lizards of the Sceloporus grammicus complex are comprised of multiple chromosome races that form several zones of parapatric hybridization in central Mexico. We scored diagnostic mitochondrial DNA (mtDNA) haplotypes and autosomal chromosome markers in a sample of 342 lizards from one well-defined zone between 2n = 34 and 2n = 46 races. A two-part analysis was performed on this data set in an attempt to infer the predominant evolutionary forces shaping the cytonuclear structure of this zone. The complications posed by its spatial structure were addressed by analysing a hierarchical series of smaller subsamples chosen to approximate single mating units. Two critical conclusions were drawn from this first-stage analysis. First and foremost, the three chromosomes have largely concordant cytonuclear disequilibrium patterns within each subsample with adequate numbers of individuals for detecting nonrandom cytonuclear associations. This suggests that the cytonuclear structure of this zone is predominantly a result of deterministic genome-wide forces rather than genetic drift of deterministic forces specific to individual chromosomes or loci. Second, the fit of a series of migration models to the data shows that the cytonuclear structure of the subsamples is well accounted for by continued gene flow from the two parental races alone, with random mating with respect to cytonuclear genotype and no other evolutionary forces. These results motivate several further empirical and theoretical investigations to refine our understanding of the relative roles of migration and other potentially important forces such as natural selection and genetic drift, in this and other hybrid zones.

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Section: S Fa Tis Tical Analysessupporting

confidence: 55%

Cytonuclear genetic structure of a hybrid zone in lizards of the Sceloporus grammicus complex (Sauria, Phrynosomatidae)

Sites¹,

Basten²,

Asmussen³

1996

Mol Ecol

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“…In L. sylvaticum, the increase of testes mass was associated with an increase in fat body mass, and mating activity occurred later in the season, when fat stores were high, a pattern reported in other viviparous lizard species, including Sceloporus grammicus (Guillette and Casas-Andreu, 1981), Liolaemus huacahuasicus (Ramirez-Pinilla, 1991), Cordylus polyzonus (Flemming, 1993), and Niveoscincus ocellatus (Wapstra and Swain, 2001). This fat storage pattern suggests that male L. sylvaticum are able to maintain positive energy balance during the reproductive season, when resources are plentiful.…”

Section: Reproductionmentioning

confidence: 53%

Reproduction and sexual dimorphism of Lepidophyma sylvaticum (Squamata: Xantusiidae), a tropical night lizard from Tlanchinol, Hidalgo, Mexico

et al. 2008

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We studied reproductive characteristics of the night lizard, Lepidophyma sylvaticum (Xantusiidae) from cloud forest in Tlanchinol, Hidalgo, Mexico. Males reached sexual maturity at a snout-vent length (SVL) of 55 mm, and females reached sexual maturity at a SVL of 56 mm. Males and females were not sexually dimorphic in SVL, but males had significantly larger heads and limbs than females. Reproduction in males and females was seasonal. Testicular mass increased in July and August, reaching maximum size in September. Minimum testes size occurred in March. Follicles of females began to increase in size in September when vitellogenesis was observed. Follicles in some females increased in mass during January-March, whereas other females ovulated during that period. Late embryonic stages (35-40) were observed in July with parturition likely occurring in July and August, coincident with maximum rainfall. Litter size averaged 4.7 ± 0.4 neonates, and was not correlated with female size. Similarities in reproductive characteristics between L. sylvaticum and other xantusiids (viviparity, long gestation period) suggest that some reproductive characteristics have a historical origin.

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“…Sperm storage is a common phenomenon in squamate reptiles (Fox,'56, '63; Saint-Girons, '75; Halpert et al,'82). It has been observed in other sceloporine species (Sceloporus jarrovi-Goldberg, '70; Sceloporus grammicus microlepidotus- Guillette and Casas-Andreu, 1981). In the viviparous populations, sperm storage appears necessary to ensure delayed fertilization, whereas this strategy may be a security measure in oviparous females.…”

Section: Discussionmentioning

confidence: 94%

Ovarian, oviductal, and placental morphology of the reproductively bimodal lizard, Sceloporus aeneus

Guillette

Jones

1985

Journal of Morphology

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108

119

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Sceloporus aeneus exhibits reproductive bimodality. That is, one taxon (Sceloporus aeneus bicanthalis) is viviparous whereas the other (Sceloporus aeneus aeneus) is oviparous. Morphological differences in luteal and oviductal structure were examined. Oviparous and viviparous females have distinct corpora lutea that form immediately after ovulation and remain active until just prior to oviposition or parturition. Luteal activity is correlated positively with follicular atresia. The oviduct of both subspecies is divided into three distinct morphological regions: an anterior infundibulum, a median uterus, and a posterior vagina. The infundibulum and vagina of females exhibiting either parity type are similar, whereas distinct differences in utering morphology are apparent. Primarily, these differences include the loss of uterine glands and a reduction in epithelial cell height in the viviparous form. Moreover, viviparous females possess a simple but well-developed chorioallantoic placenta and a simple choriovitelline placenta. Chorioallantoic placentation is associated with a significant increase in uterine vascularity, indicating a role in gas and/or water exchange. The evolution of viviparity and placentation are discussed in relation to these observations.

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Seasonal Variation in Fat Body Weights of the Mexican High Elevation Lizard Sceloporus grammicus microlepidotus

Cited by 39 publications

References 16 publications

Cytonuclear genetic structure of a hybrid zone in lizards of the Sceloporus grammicus complex (Sauria, Phrynosomatidae)

Cytonuclear genetic structure of a hybrid zone in lizards of the Sceloporus grammicus complex (Sauria, Phrynosomatidae)

Reproduction and sexual dimorphism of Lepidophyma sylvaticum (Squamata: Xantusiidae), a tropical night lizard from Tlanchinol, Hidalgo, Mexico

Ovarian, oviductal, and placental morphology of the reproductively bimodal lizard, Sceloporus aeneus

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