Lavanify

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Lavanify
Temporal range: Late Cretaceous (?Maastrichtian)
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Family: †Sudamericidae
Genus: †Lavanify
Krause et al., 1997
Species:
†L. miolaka
Binomial name
†Lavanify miolaka
Krause et al., 1997

Lavanify is a mammalian genus from the

phylogenetic relationships, and within Gondwanatheria as a member of the family Sudamericidae. Lavanify is most closely related to the Indian Bharattherium; the South American Sudamerica and Gondwanatherium
are more distantly related. Gondwanatheres probably ate hard plant material.

Lavanify had high-

perikymata
—wave-like ridges and grooves in the enamel surface.

Discovery and context

Two teeth of Lavanify were discovered in 1995–1996 during joint expeditions of the

generic name, Lavanify, means "long tooth" and the specific name, miolaka, means "curved" in Malagasy; both refer to the teeth's shape.[2]

Gondwanatheres are a small group of mammals of uncertain

grass-eating mammals.[5]

Several other mammals have been recorded from the late Cretaceous of Madagascar, mostly on the basis of isolated teeth. A possible second gondwanathere is represented by a tooth that is larger and lower-crowned than those of Lavanify, and a yet lower-crowned tooth may also be of a gondwanathere. A lower

crocodyliforms, dinosaurs, and other animals.[7]

Description

Lavanify is known from the complete cheektooth UA 8653 and the broken tooth FMNH PM 59520. Krause and colleagues could not determine whether the teeth were from the lower or upper jaw and whether they were molars or molariform (molar-like)

perikymata (ridges and grooves arranged in a transverse, wave-like pattern).[11]

UA 8653, the

dentine surrounded by enamel. One side of the crown lacks enamel.[2] Between the two arms of the V, at the lingual (inner) side of the tooth,[11] is a furrow filled with cementum, which extends all the way through the tooth; the presence of such a long furrow distinguishes it from Gondwanatherium. The enamel is made up of small, round prisms (bundles of hydroxyapatite crystals) that are separated by large, continuous bands of interprismatic matrix (IPM; the material between the enamel prisms).[2]

FMNH PM 59520 is 9.8 mm high. It is similar in many respects to UA 8653, but is less curved and its occlusal surface contains a large infundibulum (funnel-shaped cavity), filled with cementum and surrounded by enamel that penetrates deeply into the tooth. There is also either a second infundibulum or a cementum-filled furrow. The differences in degree of curvature and occlusal morphology suggest that this tooth represents a different tooth position than UA 8653. Krause and colleagues tentatively placed this tooth in Lavanify in view of the considerable variation among other gondwanathere teeth of a single species and in the absence of evidence to the contrary.[12]

Relationships

Relationships among gondwanatheres[13]

In their original description, Krause and colleagues suggested that Lavanify was most closely related to the then-unnamed Indian sudamericid. They based this proposed relationship on the shared presence of prominent, continuous bands of IPM.

synapomorphies (shared derived traits) for the Bharattherium-Lavanify clade. They also share the presence of furrows on the lingual side of the teeth only, but whether this is a derived feature is uncertain. Wilson and colleagues list two autapomorphies (unique derived traits) of Lavanify: presence of a V-shaped dentine island and absence of enamel on one side of the crown.[11] Prasad and colleagues who named Bharattherium, noted the absence of enamel on part of the crown of a Bharattherium tooth and interpreted this trait as a synapomorphy of Bharattherium and Lavanify.[16] They also mentioned the presence of a furrow and infundibulum as shared traits.[17]

References
  1. ^ Krause et al., 1997, p. 504; 2006, p. 179
  2. ^ a b c d Krause et al., 1997, p. 504
  3. ^ Wilson et al., 2007, p. 521
  4. ^ Prasad, 2008, p. 91
  5. ^ Gurovich and Beck, 2009, p. 37; Wilson et al., 2007, p. 521
  6. ^ Krause et al., 2006, pp. 186–188
  7. ^ Krause et al., 2006, p. 178
  8. ^ Wilson et al., 2007, pp. 522, 526
  9. ^ Gurovich, 2005, p. 383
  10. ^ Gurovich, 2005, p. 359
  11. ^ a b c Wilson et al., 2007, p. 526
  12. ^ Krause et al., 1997, p. 505
  13. ^ Krause et al., 1997, fig. 3; Wilson et al., 2007, p. 527; Prasad et al., 2007, p. 23
  14. ^ Krause et al., 1997, fig. 3
  15. ^ Prasad et al., 2007, p. 23; Wilson et al., 2007, p. 526
  16. ^ Prasad et al., 2007, p. 21
  17. ^ Prasad et al., 2007, pp. 21–22

Literature cited

  • Gurovich, Y. 2005. Bio-evolutionary aspects of Mesozoic mammals: description, phylogenetic relationships and evolution of the Gondwanatheria (Late Cretaceous and Paleocene of Gondwana). Ph.D. thesis, Universidad de Buenos Aires, xiii + 546 pp.
  • Gurovich, Y. and Beck, R. 2009. The phylogenetic affinities of the enigmatic mammalian clade Gondwanatheria (subscription required). Journal of Mammalian Evolution 16:25–49.
  • Krause, D.W., Prasad, G.V.R., von Koenigswald, W., Sahni, A. and Grine, F.E. 1997. Cosmopolitanism among gondwanan Late Cretaceous mammals (subscription required). Nature 390:504–507.
  • Krause, D.W., O'Connor, P.M., Rogers, K.C., Sampson, S.D., Buckley, G.A. and Rogers, R.R. 2006. Late Cretaceous terrestrial vertebrates from Madagascar: Implications for Latin American biogeography (subscription required). Annals of the Missouri Botanical Garden 93(2):178–208.
  • Prasad, G.V.R. 2008. "Sedimentary basins & fossil records" (PDF). Archived from the original (PDF) on 26 July 2011. Pp. 90–96 in Singhvi, A.K. and Bhattacharya, A. (eds.). Glimpses of Geoscience Research in India: The Indian Report to IUGS 2004–2008. New Delhi: The Indian National Science Academy (INSA).
  • Prasad, G.V.R., Verma, O., Sahni, A., Krause, D.W., Khosla, A. and Parmar, V. 2007. A new late Cretaceous gondwanatherian mammal from central India. Proceedings of the Indian National Science Academy 73(1):17–24.
  • Wilson, G.P., Das Sarma, D.C. and Anantharaman, S. 2007. Late Cretaceous sudamericid gondwanatherians from India with paleobiogeographic considerations of Gondwanan mammals (subscription required). Journal of Vertebrate Paleontology 27(2):521–531.

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