''Lavanify'' is a mammalian genus from the
late Cretaceous
The Late Cretaceous (100.5–66 Ma) is the more recent of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''cre ...
(probably
Maastrichtian
The Maastrichtian ( ) is, in the International Commission on Stratigraphy (ICS) geologic timescale, the latest age (geology), age (uppermost stage (stratigraphy), stage) of the Late Cretaceous epoch (geology), Epoch or Upper Cretaceous series (s ...
, about 71 to 66 million years ago) of
Madagascar
Madagascar, officially the Republic of Madagascar, is an island country that includes the island of Madagascar and numerous smaller peripheral islands. Lying off the southeastern coast of Africa, it is the world's List of islands by area, f ...
. The only species, ''L. miolaka'', is known from two isolated teeth, one of which is damaged. The teeth were collected in 1995–1996 and described in 1997. The animal is classified as a member of
Gondwanatheria
Gondwanatheria is an extinct group of mammaliaforms that lived in parts of Gondwana, including Madagascar, India, South America, Africa, and Antarctica during the Upper Cretaceous through the Miocene (and possibly much earlier, if '' Allostaffia' ...
, an enigmatic extinct group with unclear
phylogenetic
In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as phylogenetic inference. It infers the relationship among organisms based on empirical dat ...
relationships, and within Gondwanatheria as a member of the family
Sudamericidae
Sudamericidae is a family of gondwanathere mammals that lived during the late Cretaceous to Miocene. Its members include '' Lavanify'' and '' Vintana'' from the Cretaceous of Madagascar, '' Bharattherium'' (=''Dakshina'') from the Cretaceous of I ...
. ''Lavanify'' is most closely related to the Indian ''
Bharattherium
''Bharattherium'' is a mammal that lived in India during the Maastrichtian (latest Cretaceous) and possibly the Paleocene. The genus has a single species, ''Bharattherium bonapartei''. It is part of the gondwanathere family Sudamericidae, which is ...
''; the South American ''
Sudamerica
''Sudamerica'', literally "South America" in Spanish, is a genus of mammal from the extinct suborder Gondwanatheria that lived in Patagonia, Argentina (Salamanca Formation) and Antarctica (La Meseta Formation) from the Middle Paleocene (Peligra ...
'' and ''
Gondwanatherium
''Gondwanatherium'' is a genus of stem-mammal from the extinct suborder Gondwanatheria that lived in Patagonia, South America during the "Age of Dinosaurs", specifically during the Late Cretaceous (Campanian to Maastrichtian epochs).
Descripti ...
'' are more distantly related. Gondwanatheres probably ate hard plant material.
''Lavanify'' had high-
crowned, curved teeth. One of the two teeth is 11.2 mm high and shows a deep furrow and, is centered laterally in the crown, a V-shaped area that consists of
dentine
Dentin ( ) (American English) or dentine ( or ) (British English) () is a calcified tissue of the body and, along with enamel, cementum, and pulp, is one of the four major components of teeth. It is usually covered by enamel on the crown ...
. The other, damaged, tooth is 9.8 mm high and has at least one deep cavity (infundibulum). Characters shared by the teeth of ''Lavanify'' and ''Bharattherium'' include the presence of an infundibulum and a furrow; they both also have large, continuous bands of matrix (unbundled
hydroxyapatite
Hydroxyapatite (International Mineralogical Association, IMA name: hydroxylapatite) (Hap, HAp, or HA) is a naturally occurring mineral form of calcium apatite with the Chemical formula, formula , often written to denote that the Crystal struc ...
crystals) between the prisms (bundles of hydroxyapatite crystals) of the
enamel, and
perikymata
Perikymata (Greek plural of περικύμα, perikyma) are incremental growth lines that appear on the surface of tooth enamel as a series of linear grooves. In anatomically modern humans, each perikyma takes approximately 6–12 days to form. T ...
—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
State University of New York
The State University of New York (SUNY ) is a system of Public education, public colleges and universities in the New York (state), State of New York. It is one of the List of largest universities and university networks by enrollment, larges ...
,
Stony Brook University
Stony Brook University (SBU), officially the State University of New York at Stony Brook, is a public university, public research university in Stony Brook, New York, United States, on Long Island. Along with the University at Buffalo, it is on ...
, and the
University of Antananarivo
University of Antananarivo () is the primary public university of Madagascar, located in the capital Antananarivo.
History
The university traces its founding to 16 December 1955 and the formation of the Institute for Advanced Studies in Antan ...
to the
late Cretaceous
The Late Cretaceous (100.5–66 Ma) is the more recent of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''cre ...
(mostly
Maastrichtian
The Maastrichtian ( ) is, in the International Commission on Stratigraphy (ICS) geologic timescale, the latest age (geology), age (uppermost stage (stratigraphy), stage) of the Late Cretaceous epoch (geology), Epoch or Upper Cretaceous series (s ...
, about 71 to 66 million years ago
ya Maevarano Formation
The Maevarano Formation is a Late Cretaceous sedimentary formation (geology), rock formation found in the Mahajanga Province of northwestern Madagascar. It is most likely Maastrichtian in age, and records a seasonal, semiarid environment with rive ...
of northwestern Madagascar. The two teeth were found in different sites in a white
sandstone
Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sand ...
unit of the Maevarano Formation near the village of
Berivotra
Berivotra is a rural municipality in Madagascar. It belongs to the district of Maevatanana, which is a part of Betsiboka Region. The population of the municipality was 14,675 in 2018.
Infrastructure
It is situated on the Route Nationale 4 fro ...
and have been deposited in the collections of the University of Antananarivo (specimen UA 8653) and
Field Museum of Natural History
The Field Museum of Natural History (FMNH), also known as The Field Museum, is a natural history museum in Chicago, Illinois, and is one of the largest such museums in the world. The museum is popular for the size and quality of its educationa ...
(specimen FMNH PM 59520).
David W. Krause and colleagues described ''Lavanify'' and a
sudamericid
Sudamericidae is a family of gondwanathere mammals that lived during the late Cretaceous to Miocene. Its members include ''Lavanify'' and ''Vintana'' from the Cretaceous of Madagascar, ''Bharattherium'' (=''Dakshina'') from the Cretaceous of Indi ...
from India, which they did not name, in a 1997 paper in ''
Nature
Nature is an inherent character or constitution, particularly of the Ecosphere (planetary), ecosphere or the universe as a whole. In this general sense nature refers to the Scientific law, laws, elements and phenomenon, phenomena of the physic ...
''. These were the first
gondwanathere
Gondwanatheria is an extinct group of mammaliaforms that lived in parts of Gondwana, including Madagascar, India, South America, Africa, and Antarctica during the Upper Cretaceous through the Miocene (and possibly much earlier, if '' Allostaffia' ...
mammals to be found outside of Argentina and provided evidence that the mammal faunas of the different
Gondwana
Gondwana ( ; ) was a large landmass, sometimes referred to as a supercontinent. The remnants of Gondwana make up around two-thirds of today's continental area, including South America, Africa, Antarctica, Australia (continent), Australia, Zea ...
n (southern) continents were similar to each other. The
generic name, ''Lavanify'', means "long tooth" and the
specific name Specific name may refer to:
* in Database management systems, a system-assigned name that is unique within a particular database
In taxonomy, either of these two meanings, each with its own set of rules:
* Specific name (botany), the two-part (bino ...
, ''miolaka'', means "curved" in
Malagasy; both refer to the teeth's shape.
[Krause et al., 1997, p. 504]
Gondwanatheres are a small group of mammals of uncertain
phylogenetic
In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as phylogenetic inference. It infers the relationship among organisms based on empirical dat ...
affinities known from the late Cretaceous to the
Eocene
The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...
(~56–34 mya) of the Gondwanan continents, known only from teeth and a few lower jaws. Upon their discovery in the 1980s, gondwanatheres were initially thought to be
xenarthra
Xenarthra (; from Ancient Greek ξένος, xénos, "foreign, alien" + ἄρθρον, árthron, "joint") is a superorder and major clade of placental mammals native to the Americas. There are 31 living species: the anteaters, tree sloths, and ...
ns—part of the same group as living
sloth
Sloths are a Neotropical realm, Neotropical group of xenarthran mammals constituting the suborder Folivora, including the extant Arboreal locomotion, arboreal tree sloths and extinct terrestrial ground sloths. Noted for their slowness of move ...
s,
armadillo
Armadillos () are New World placental mammals in the order (biology), order Cingulata. They form part of the superorder Xenarthra, along with the anteaters and sloths. 21 extant species of armadillo have been described, some of which are dis ...
s, and
anteater
Anteaters are the four extant mammal species in the suborder Vermilingua (meaning "worm tongue"), commonly known for eating ants and termites. The individual species have other names in English and other languages. Together with sloths, they ar ...
s—but later workers have favored affinities with
multituberculate
Multituberculata (commonly known as multituberculates, named for the multiple tubercles of their teeth) is an extinct order of rodent-like mammals with a fossil record spanning over 130 million years. They first appeared in the Middle Jurassic, a ...
s (a diverse group of fossil mammals) or left the relationships of the gondwanatheres open. The group comprises two
families
Family (from ) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictability, structure, and safety as ...
. The family
Ferugliotheriidae
Ferugliotheriidae is one of three known families in the order Gondwanatheria, an enigmatic group of extinct mammals. Gondwanatheres have been classified as a group of uncertain affinities or as members of Multituberculata, a major extinct mammali ...
, whose members had low-crowned teeth, occurs in the
Campanian
The Campanian is the fifth of six ages of the Late Cretaceous epoch on the geologic timescale of the International Commission on Stratigraphy (ICS). In chronostratigraphy, it is the fifth of six stages in the Upper Cretaceous Series. Campa ...
(~84–71 mya) to Maastrichtian of Argentina. All other gondwanatheres, including ''Lavanify'', are placed in the Sudamericidae, which have high-crowned (
hypsodont
Hypsodont is a pattern of dentition characterized by with high crowns, providing extra material for wear and tear. Some examples of animals with hypsodont dentition are cows and horses; all animals that feed on gritty, fibrous material. The oppos ...
) teeth. These include ''
Gondwanatherium
''Gondwanatherium'' is a genus of stem-mammal from the extinct suborder Gondwanatheria that lived in Patagonia, South America during the "Age of Dinosaurs", specifically during the Late Cretaceous (Campanian to Maastrichtian epochs).
Descripti ...
'' from the Campanian and Maastrichtian of Argentina; ''
Sudamerica
''Sudamerica'', literally "South America" in Spanish, is a genus of mammal from the extinct suborder Gondwanatheria that lived in Patagonia, Argentina (Salamanca Formation) and Antarctica (La Meseta Formation) from the Middle Paleocene (Peligra ...
'' from the
Paleocene
The Paleocene ( ), or Palaeocene, is a geological epoch (geology), epoch that lasted from about 66 to 56 mya (unit), million years ago (mya). It is the first epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), ...
(~66–56 mya) of Argentina; ''Lavanify''; at least one species from the Maastrichtian of India; an unnamed species related to ''Sudamerica'' from the Eocene of Antarctica; and an unnamed possible gondwanathere,
TNM 02067
''Galulatherium'' is an extinct genus of possibly gondwanathere mammal, from the Late Cretaceous (Turonian-Campanian)-aged Galula Formation of Tanzania.P. M. O'Connor, D. W. Krause, N. J. Stevens, J. R. Groenke, R. D. E. MacPhee, D. C. Kalthoff, ...
, from the Cretaceous of Tanzania. In 2007, teams led by G.P. Wilson and G.V.R. Prasad independently described this animal as ''Dakshina'' and ''
Bharattherium
''Bharattherium'' is a mammal that lived in India during the Maastrichtian (latest Cretaceous) and possibly the Paleocene. The genus has a single species, ''Bharattherium bonapartei''. It is part of the gondwanathere family Sudamericidae, which is ...
'' respectively; as the latter name was published first, it is the correct name for this genus according to the
Principle of Priority
Priority is a principle in Taxonomy (biology), biological taxonomy by which a valid scientific name is established based on the oldest available name. It is a decisive rule in Botanical nomenclature, botanical and zoological nomenclature to recogn ...
. Gondwanatheres have been interpreted as feeding on roots, bark, and abrasive vegetation or as the earliest
grass-eating mammals.
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
molar,
UA 8699, may be of a
marsupial
Marsupials are a diverse group of mammals belonging to the infraclass Marsupialia. They are natively found in Australasia, Wallacea, and the Americas. One of marsupials' unique features is their reproductive strategy: the young are born in a r ...
or a
placental
Placental mammals (infraclass Placentalia ) are one of the three extant subdivisions of the class Mammalia, the other two being Monotremata and Marsupialia. Placentalia contains the vast majority of extant mammals, which are partly distinguished ...
and a molar fragment is referable to
Multituberculata
Multituberculata (commonly known as multituberculates, named for the multiple tubercles of their teeth) is an extinct Order (biology), order of rodent-like mammals with a fossil record spanning over 130 million years. They first appeared in the M ...
. Finally, an as-yet-undescribed mammal is known from a fairly complete skeleton. None of these mammals is related to the living mammals of the island, many of which belong to unique groups (see
List of mammals of Madagascar
This is a list of the native wild mammal species recorded in Madagascar. As of June 2014 (following the IUCN reassessment of the lemurs) there are 241 extant taxon, extant mammal species recognized in Madagascar, of which 22 are critically endanger ...
). The fauna also contains
crocodyliform
Crocodyliformes is a clade of Crurotarsi, crurotarsan archosaurs, the group often traditionally referred to as "crocodilians". They are the first members of Crocodylomorpha to possess many of the features that define later relatives. They are the ...
s,
dinosaur
Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic Geological period, period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the #Evolutio ...
s, and other animals.
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)
premolar
The premolars, also called premolar Tooth (human), teeth, or bicuspids, are transitional teeth located between the Canine tooth, canine and Molar (tooth), molar teeth. In humans, there are two premolars per dental terminology#Quadrant, quadrant in ...
s, but suggested that they represented two different tooth positions.
[ However, Wilson and colleagues in 2007 tentatively identified UA 8653 as a left fourth (last) lower molariform (mf4); because molars and premolars of gondwanatheres cannot be reliably distinguished, the term "molariform" is used instead. FMNH PM 59520 resembles the ''Gondwanatherium'' fossil MACN Pv-RN 1027, a broken tooth that may be an upper molariform. In both ''Lavanify'' teeth, the enamel surface features ]perikymata
Perikymata (Greek plural of περικύμα, perikyma) are incremental growth lines that appear on the surface of tooth enamel as a series of linear grooves. In anatomically modern humans, each perikyma takes approximately 6–12 days to form. T ...
(ridges and grooves arranged in a transverse, wave-like pattern).[
UA 8653, the ]holotype
A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...
, is hypsodont and curved. It is 11.2 mm high, of which the crown makes up about 85%, and the dimensions of its crown are 3.4 x 3.2 mm. The occlusal (chewing) surface is worn flat and contains a V-shaped island of dentine
Dentin ( ) (American English) or dentine ( or ) (British English) () is a calcified tissue of the body and, along with enamel, cementum, and pulp, is one of the four major components of teeth. It is usually covered by enamel on the crown ...
surrounded by enamel. One side of the crown lacks enamel.[ Between the two arms of the V, at the lingual (inner) side of the tooth,][Wilson et al., 2007, p. 526] is a furrow filled with cementum
Cementum is a specialized calcified substance covering the root of a tooth. The cementum is the part of the periodontium that attaches the teeth to the alveolar bone by anchoring the periodontal ligament.
Structure
The cells of cementum are ...
, 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
Hydroxyapatite (International Mineralogical Association, IMA name: hydroxylapatite) (Hap, HAp, or HA) is a naturally occurring mineral form of calcium apatite with the Chemical formula, formula , often written to denote that the Crystal struc ...
crystals) that are separated by large, continuous bands of interprismatic matrix (IPM; the material between the enamel prisms).[
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 An infundibulum (Latin for ''funnel''; plural, ''infundibula'') is a funnel-shaped cavity or organ.
Anatomy
* Brain: the pituitary stalk, also known as the ''infundibulum'' and ''infundibular stalk'', is the connection between the hypothalamus an ...
(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.[Krause et al., 1997, p. 505]
Relationships
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.[Krause et al., 1997, fig. 3] The teams who named the Indian gondwanathere in 2007 both agreed with this proposed relationship. In their description of ''Dakshina'', Wilson and colleagues added the presence of an infundibulum and of perikymata to the evidence for the relationship between the two. These three characters are synapomorphies
In phylogenetics, an apomorphy (or derived trait) is a novel character or character state that has evolved from its ancestral form (or plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxa and is therefore hypothesized to ...
(shared derived traits) for the ''Bharattherium-Lavanify'' clade
In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...
. 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
In phylogenetics, an autapomorphy is a distinctive feature, known as a derived trait, that is unique to a given taxon. That is, it is found only in one taxon, but not found in any others or outgroup taxa, not even those most closely related to ...
(unique derived traits) of ''Lavanify'': presence of a V-shaped dentine island and absence of enamel on one side of the crown.[ 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''.][Prasad et al., 2007, p. 21] They also mentioned the presence of a furrow and infundibulum as shared traits.[Prasad et al., 2007, pp. 21–22]
References
Literature cited
*Gurovich, Y. 2005. . 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. 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.
{{featured article
Maevarano fauna
Cretaceous mammals
Fossil taxa described in 1997
Gondwanatheria
Prehistoric animals of Madagascar
Taxa named by David W. Krause
Taxa named by Guntupalli Veera Raghavendra Prasad
Taxa named by Wighart von Koenigswald
Taxa named by Ashok Sahni
Taxa named by Frederick E. Grine