Phylogenetic relationships of the genus Sibynophis (Serpentes: Colubroidea)

Zaher, Hussam; Grazziotin, Felipe G.; Graboski, Roberta; Fuentes, Ricardo G; Sánchez‐Martínez, Paola María; Montingelli, Giovanna G.; Zhang, Yaping; Murphy, Robert W.

doi:10.1590/s0031-10492012001200001

Cited by 10 publications

(17 citation statements)

References 16 publications

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“…To test whether adrenal enlargement has occurred repeatedly in separate lineages of colubroid snakes, we selected four phylogenetically independent species pairs, each consisting of one bufophagous and one nonbufophagous species. The relationships among the eight study taxa, based on the recent phylogenies of Pyron et al (2011) and Zaher et al (2012), are shown in Fig. 2.…”

Section: Selection Of Study Speciesmentioning

confidence: 90%

“…() and Zaher et al . (). Nonbufophagous lineages are in gray, bufophagous lineages are in black; names of bufophagous species are in bold.…”

Section: Methodsmentioning

confidence: 99%

“…Relationships among the eight study species based on the extensive phylogenies of colubroid snakes presented by Pyron et al (2011) and Zaher et al (2012) (Mulcahy, 2008).…”

Section: Figurementioning

confidence: 99%

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Independentlyevolved toad‐eating snakes exhibit sexually dimorphic enlargement of adrenal glands

et al. 2013

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Toads are defended chemically by bufadienolides, a class of cardiotonic steroids lethal to most predators. Bufadienolides bind to Na+,K+‐ATPases, inhibiting the ability of those cellular pumps to transport ions. In cardiocytes, this inhibition causes arrhythmia and increased contractile strength, which, if prolonged, lead to death. However, several snakes are resistant to bufadienolides and consume toads with no apparent ill effects. Adrenal glands produce hormones that function in the maintenance of Na+,K+‐ATPases, and may therefore play an important role in countering the negative effects of bufadienolides. We hypothesized that bufophagous (toad‐eating) snakes have enlarged adrenal glands that contribute to the snakes' resistance to bufadienolides, and that sexual dimorphism in adrenal gland size is a general characteristic of bufophagous snakes. We compared phylogenetically independent pairs of taxa to investigate differences in adrenal morphology between bufophagous and nonbufophagous species. We also compared adrenal masses between males and females of bufophagous and nonbufophagous species to test whether sexual dimorphism in adrenal size reported for one species of bufophagous snakes represents a more widespread phenomenon. Our results demonstrate for the first time that the allometric relationship between adrenal mass and body size is significantly different between several bufophagous species and related nonbufophagous species; adrenal size differs between males and females in those bufophagous species, with males having larger adrenal glands, but no such dimorphism exists in related nonbufophagous species. These results demonstrate that parallel morphological responses have occurred repeatedly in bufophagous snakes and suggest that the adrenal glands play a role in mediating the negative effects of bufadienolide ingestion in bufophagous snakes.

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Section: Selection Of Study Speciesmentioning

confidence: 90%

“…() and Zaher et al . (). Nonbufophagous lineages are in gray, bufophagous lineages are in black; names of bufophagous species are in bold.…”

Section: Methodsmentioning

confidence: 99%

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Independentlyevolved toad‐eating snakes exhibit sexually dimorphic enlargement of adrenal glands

et al. 2013

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“…The relationships of the gut tube to the skeleton were determined from serial sections of whole heads and anterior trunks of a small sample of colubroid snakes (Appendix A), a clade that includes the majority of living snake species (Gauthier et al, ; Zaher et al, ; Pyron et al, ). Data came from four juvenile watersnakes ( Nerodia sipedon ) sectioned specifically to look at esophageal relationships plus serial sections of the heads of other snakes prepared for general features of head anatomy (Cundall and Shardo, ).…”

Section: Methodsmentioning

confidence: 99%

A Model of the Anterior Esophagus in Snakes, with Functional and Developmental Implications

Cundall

Tuttman

2014

The Anatomical Record

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The gross anatomy of the mouth of snakes has always been interpreted as an evolutionary response to feeding demands. In most alethinophidian species, their anatomy allows limited functional independence of right and left sides and the roof and floor of the mouth as well as wide separation of the tips of the mandibles. However, locations of the tongue and glottis in snakes suggest extraordinary rearrangement of pharyngeal structures characteristic of all vertebrates. Serial histological sections through the heads of a number of colubroid species show muscularis mucosal smooth muscle fibers appearing in the paratracheal gutter of the lower jaw at varying levels between the eye and ear regions. Incomplete muscularis externa elements appear beneath the paratracheal gutter more caudally but typically at otic levels. Both muscle layers encompass more of the gut wall at more posterior levels, encircling the gut at the level of the atlas or axis. The pattern in snakes suggests developmental dissociation of dorsal and ventral splanchnic derivatives and extensive topological rearrangements of some ventral pharyngeal arch derivatives typical of most tetrapods. When snakes swallow large prey, the effective oral cavity becomes extremely short ventrally. The palatomaxillary arches function as ratchets packing the prey almost directly into the esophagus. Our findings raise questions about germ layer origins and regulation of differentiation of gut regions and derivatives in snakes and suggest that significant aspects of the evolution of lepidosaurs may be difficult to recover from bones or molecular sequence data alone. Anat Rec,

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“…The direct examination of several colubroid genera (e.g., Apostolepis , Boiruna , Erythrolamprus , Helicops , Hydrops , Philodryas , Pseudoeryx , Sordellina , Xenodon —see Supporting Information Appendix I for a list of the species analyzed), combined with literature data (e.g., Mao et al, ; Zaher, ; Harvey and Embert, ; Silva and Rodrigues, ; Guo et al, ; Klaczko et al, ; Montingelli et al, ; Zaher et al, ) corroborates the widespread occurrence of hemipenial spines in the lineage. In contrast, more basal radiations of the Serpentes, such as Cylindrophiidae (Stuebing, ), Leptotyphlopidae (Passos et al, ; Pinto and Curcio, ; Pinto and Fernandes, ), Boidae (Passos and Fernandes, ), and Tropidophiidae (Stull, ; Gibson, ; Curcio et al, ) seem to lack calcified ornaments.…”

Section: Resultsmentioning

confidence: 99%

Are Hemipenial Spines Related to Limb Reduction? A Spiny Discussion Focused on Gymnophthalmid Lizards (Squamata: Gymnophthalmidae)

Nunes

Curcio

Roscito

et al. 2014

The Anatomical Record

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Calcified spines in the hemipenial surface occur convergently in several gymnophthalmid lizard species and in advanced snakes. Based on the pronounced degrees of limb reduction in these distantly related lineages, such hemipenial structures were suggested to play a functional role in couple-anchoring during copulation, partly assuming the function of the limbs during mating. Herein, we assessed the hemipenial morphology of virtually all the valid genera of the family Gymnophthalmidae to test for a phylogenetic correlation between limb reduction and the presence of calcified hemipenial spines. The occurrence of calcified structures was mapped on the two most comprehensive phylogenies of the family. We concluded that spiny hemipenes are by no means necessarily associated with reduction of limbs. Conversely, the presence of well-developed hemipenial spines in specific limb-reduced taxa does not allow one to disregard the possibility that in some instances such structures might indeed be functionally associated with couple-anchoring, improving the success of mating. Anat Rec,

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Phylogenetic relationships of the genus Sibynophis (Serpentes: Colubroidea)

Cited by 10 publications

References 16 publications

Independentlyevolved toad‐eating snakes exhibit sexually dimorphic enlargement of adrenal glands

Independentlyevolved toad‐eating snakes exhibit sexually dimorphic enlargement of adrenal glands

A Model of the Anterior Esophagus in Snakes, with Functional and Developmental Implications

Are Hemipenial Spines Related to Limb Reduction? A Spiny Discussion Focused on Gymnophthalmid Lizards (Squamata: Gymnophthalmidae)

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