cleithrum

cleithrum

[′klī·thrəm]
(vertebrate zoology)
A bone external and adjacent to the clavicle in certain fishes, stegocephalians, and primitive reptiles.
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References in periodicals archive ?
The long, mid-posterior preopercular spine extended beyond the cleithrum.
A distinctive membranous structure on anterior edge of cleithrum that appears juxtaposed to first lateral scales, and covered with a great number of highly ramified complex tubules.
However, the small but robust supracleithrum (which one might expect to be removed with the cleithrum to which it is articulated) is not particularly under-represented.
Two internal melanophores are present in the posterior head region; one is located in the middle of the cleithrum near the base of the pectoral bud and the second is located on the base of the brain near the cleithrum.
A monogeneric atheriniform family with the parasphenoid concave rather than convex, parasphenoid myodomes present; mesethmoid morphology unique, nasal septum formed by ethmoid and mesethmoid; parietals not contributing to posttemporal fossa; anterior vertebral parapophyses with lateral ridges; interdorsals absent; cleithrum dorsal enclosure absent; membrane just posterior to genital opening; and pelvic posteromedial process elongate.
In cases where one or more of five skull bones (maxilla, premaxilla, dentary, cleithrum, opercle) were found intact, and in good overall condition, these bones were collected for the purpose of back-calculating original bluefish size with a series of predictive equations (Wood, 2005).
The cleithrum, present at first feeding as a thin band, thickens with growth.