Madtsoiidae

Diagram of the fossil of Sanajeh

Madtsoiidae was first classified as a subfamily of Boidae, Madtsoiinae, in Hoffstetter (1961). Further study and new finds allowed ranking the group as a distinct family in Linnaean systems. With the recent use of cladistics to unravel phylogeny, various analyses have posited Madtsoiidae as a likely clade within Serpentes, or possible paraphyletic stem group outside Serpentes and within a more inclusive Ophidia. Madtsoiid snakes ranged in size from less than 1 metre (3.3 ft) (estimated total length) to over 9 metres (30 ft), and are thought to have been constrictors analogous to modern pythons and boas, but with more primitive jaw structures less highly adapted for swallowing large prey. There are specific anatomical features that diagnose members of this family, such as the presence of hypapophyses only in anterior trunk, that the middle and posterior trunk vertebrae possess a moderately or well-developed haemal keel, except for a few near the cloacal region, often with short laterally paired projections on the posterior part of the keel. Also, all trunk and caudal vertebrae have at least a parazygantral foramen, sometimes several of them, located in a more or less distinct fossa that is lateral to each zygantral facet. Additional features are the prezygapophyseal processes' absence while the paracotylar foramina are present and that the diapophyses are relatively wide, exceeding width across prezygapophyses at least in the posterior trunk vertebrae. (Scanlon 2005)

Like most fossil snakes the majority of madtsoiids are known only from isolated vertebrae, but several (Madtsoia bai, M. camposi, Wonambi naracoortensis, Nanowana spp., unnamed Yurlunggur spp., Najash rionegrina) have associated or articulated parts of skeletons. Of the genera listed below, all have been referred to Madtsoiidae in all recent classifications except Najash rionegrina, which is included here based on diagnostic vertebral characters described by Apesteguía and Zaher (2006). These authors didn't include Najash among madtsoiids because they consider that madtsoiids are a paraphyletic assemblage of basal macrostomatans related to Madtsoia bai and consequently, not related to the Cretaceous alethinophidians from southern continents.

Wonambi naracoortensis and Thylacoleo

Rieppel et al. (2002) classified Wonambi naracoortensis within the extant radiation, (crown group), of snakes as Macrostomata incertae sedis, but many of their character state attributions for this species have been criticised or refuted by Scanlon (2005) and the better-preserved skulls of Yurlunggur sp./spp. have numerous characters apparently more plesiomorphic than any macrostomatans (Scanlon 2006). The partial skull attributed to Najash rionegrina (Apesteguía and Zaher 2006) resembles that of the non-madtsoiid Dinilysia patagonica, and vertebrae support that they are related. The type material of Najash is the only possible madtsoiid specimen retaining evidence of pelvic and hindlimb elements, which are claimed to be more plesiomorphic than other Cretaceous limbed snakes, such as Pachyrhachis, Haasiophis or Eupodophis, in retaining a sacro-iliac contact and well-developed limbs, with a huge and well-defined trochanter. The sacro iliac contact is perhaps misleadingly described by Apesteguía and Zaher as unique possession of a sacrum, whereas it has rarely been questioned that the cloacal vertebrae in snakes are homologous to the sacrals of limbed squamates (i.e. the sacrum is present but has lost contact with the reduced ilia in other taxa). It would be unsurprising if other madtsoiids also possessed hindlimbs as complete as those of Najash.

Several madtsoiid genera have been named using indigenous words for legendary Rainbow Serpents or dragons, including Wonambi (Pitjantjatjara), Yurlunggur (Yolngu) and Nanowana (Ancient Greek nano-, 'dwarf' + Warlpiri Wana) in Australia, and Herensugea (Basque) in Europe. G.G. Simpson (1933) apparently started this trend by compounding Madtsoia from indigenous roots. In this particular case these originated from the Tehuelche language, although the reference made was geographic rather than mythological, the derivation being from that language's terms mad, "valley" and tsoi, "cow" as a rough translation from Spanish name of the type locality, Cañadón Vaca.

• Gigantophis Andrews, 1901
  • Gigantophis garstini Andrews, 1901 (Andrews 1906, Hoffstetter 1961b; Paleogene, Late Eocene; Egypt (Birket Qarun and Qasr el-Sagha Formations), Libya)
• Madtsoia Simpson, 1933
  • Madtsoia bai Simpson, 1933 (Paleogene, Early Eocene Sarmiento Formation; Argentina)
  • Madtsoia cf. M. bai (Simpson 1935, Hoffstetter 1960; Paleogene, Late Paleocene Las Flores Formation; Argentina)
  • Madtsoia madagascariensis Hoffstetter, 1961a (Piveteau 1933; Cretaceous, Santonian or Campanian Maevarano Formation; Madagascar)
  • Madtsoia aff. madagascariensis (de Broin et al. 1974; Cretaceous, Coniacian or Santonian In Beceten Formation, Niger)
  • Madtsoia laurasiae Rage, 1996 (Astibia et al. 1990; Cretaceous, Campanian or Maastrichtian; Spain)
  • Madtsoia camposi Rage, 1998 (Paleogene, middle Paleocene Itaboraí Formation; Brazil)
• Wonambi Smith, 1976
  • Wonambi naracoortensis Smith, 1976 (Scanlon and Lee 2000, Scanlon 2005; Neogene, Pliocene to Pleistocene; Australia)
  • Wonambi barriei Scanlon in Scanlon and Lee, 2000 (Neogene, early Miocene; Australia)
• Patagoniophis Albino, 1986
  • Patagoniophis parvus Albino, 1986 (Cretaceous, Campanian or Maastrichtian Los Alamitos Formation; Argentina)
  • Patagoniophis australiensis Scanlon, 2005 (Scanlon 1993; Paleogene, early Eocene; Australia)
• Alamitophis Albino, 1986
  • Alamitophis argentinus Albino, 1986 (Cretaceous, Campanian or Maastrichtian Los Alamitos and La Colonia Formations; Argentina)
  • Alamitophis elongatus Albino, 1994 (Cretaceous, Campanian or Maastrichtian Allen Formation; Argentina)
  • Alamitophis tingamarra Scanlon, 2005 (Scanlon 1993; Paleogene, early Eocene; Australia)
• Rionegrophis Albino, 1986
  • Rionegrophis madtsoioides Albino, 1986 (Cretaceous, Campanian or Maastrichtian Los Alamitos Formation; Argentina)
• Yurlunggur Scanlon, 1992
  • Yurlunggur camfieldensis Scanlon, 1992 (Neogene, middle Miocene Bullock Creek (Northern Territory); Australia)
  • Yurlunggur spp. (Scanlon 2004, 2006; Paleogene-Neogene, Oligocene to Miocene; Australia)
• Herensugea Rage, 1996
  • Herensugea caristiorum Rage, 1996 (Cretaceous, Campanian or Maastrichtian Vitoria Formation; Spain)
• Nanowana Scanlon, 1997
  • Nanowana godthelpi Scanlon, 1997 (Neogene, early-to-middle Miocene Australian Fossil Mammal Sites (Riversleigh); Australia)
  • Nanowana schrenki Scanlon, 1997 (Neogene, early-to-middle Miocene; Australia)
• Sanajeh Wilson et al., 2010
  • Sanajeh indicus Wilson et al., 2010 (Cretaceous, Maastrichtian Lameta Formation; India)[1]
• Menarana Laduke et al., 2010
  • Menarana nosymena Laduke et al., 2010 (Late Cretaceous, Maastrichtian Maevarano Formation; Madagascar)[2]
• Nidophis Vasile et al., 2013
  • Nidophis insularis Vasile et al., 2013 (Late Cretaceous, Maastrichtian Densus-Ciula Formation; Romania)