Madtsoiidae Hoffstetter, 1961

Scanlon, John D., 2005, Cranial morphology of the Plio-Pleistocene giant madtsoiid snake Wonambi naracoortensis, Acta Palaeontologica Polonica 50 (1), pp. 139-180 : 141-142

Madtsoiidae Hoffstetter, 1961

Diagnosis.—Snakes of small to very large size; hypapophyses present only in anterior trunk; middle and posterior trunk vertebrae with moderately or well developed haemal keel (except a few near the cloacal region), often with short laterally paired projections on the posterior part of the keel. All trunk and caudal vertebrae with a parazygantral foramen (or sometimes several foramina) in a more or less distinct fossa lateral to each zygantral facet; prezygapophyseal processes absent; paracotylar foramina present; diapophyses relatively wide, exceeding width across prezygapophyses at least in posterior trunk vertebrae (Scanlon in press, modified from Rage 1998).

Remarks.—Polarity of some characters listed above remains uncertain. Additional apomorphies have been identified in phylogenetic analysis but may not apply to all included taxa ( Lee and Scanlon 2002: table 2; see remarks on diagnosis in Scanlon in press). Monophyly of Madtsoiidae is accepted provisionally while there is insufficient contradictory evidence, but remains weakly supported as long as any of the included taxa are poorly known ( Rage 1998; Rage and Werner 1999; Scanlon 2003). Due to the inferred phylogenetic position of this group outside the clade containing all extant snakes ( Scanlon 1996; Scanlon and Lee 2000; Lee and Scanlon 2002), it is referred to Ophidia (defined as in Lee 1998) but not to Serpentes Linnaeus, 1758; the latter is restricted to “crown clade” snakes, i.e., the least inclusive clade containing all extant snake taxa (Scolecophidia+Alethinophidia, collectively referred to as “modern snakes”).