zygosphene


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zygosphene

(ˈzaɪɡəʊˌsfiːn)
n
(Zoology) zoology a linking part of the vertebrae of snakes and lizards which fits into a zygantrum
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References in periodicals archive ?
The zygosphene can be seen in the cranial side of the anterior vertebra in UPUAM 14072a.
UPUAM 14072c presents the right blade of the zygosphene and the base of the left prezygapophysis (Fig.
The combination of characters that identify the fossil to Leptotyphlops include absence of a neural spine; zygosphene wide and thin; prezygapophyseal facets elongated and strongly anteriorly directed; posterior ends of neural arch extended medially; condyle and cotyle dorsoventrally compressed; hemal keel indistinguishable from centrum; and no subcentral ridges.
in that it is rather short and wide, the zygosphene is thick, and the hypapophysis base is thick like a viperid.
getulus based on the presence of a flat zygosphene (usually arched in L.
2): neonates, vertebrae small with round neural canals that are larger than the condyles, and thin vertebral features, especially the neural arch buttresses (bone area that connects the neural arch proper and the centrum) and the zygosphenes; juveniles, vertebrae larger with larger and more arched neural canals that range from about the size of the condyles to slightly smaller, and thicker neural arch buttresses and zygosphenes; and adults, vertebrae largest with arched neural canals that are much smaller than the condyles, and thick, robust neural arch buttresses and zygosphenes.
The trunk vertebrae exhibit features characteristic of Rhinocheilus lecontei as enumerated by Hill (1971), namely flat zygosphenes in anterior view; obovate to oval prezygapophysial faces; thick neural spines (within the colubrines) that are also flat dorsally, overhanging centra posteriorly, with indented anterior and posterior edges; short centra, no epizygapophysial spines; depressed neural arches; round to slightly compressed cotyla; postzygapophysial faces that are obovate to orbicular, strongly developed hemal keels and subcentral ridges, and swollen, very flat accessory processes.