Lavanify
Encyclopedia
Lavanify is a mammalian genus from the late Cretaceous
Late Cretaceous
The Late Cretaceous is the younger of two epochs into which the Cretaceous period is divided in the geologic timescale. Rock strata from this epoch form the Upper Cretaceous series...

 (probably Maastrichtian
Maastrichtian
The Maastrichtian is, in the ICS' geologic timescale, the latest age or upper stage of the Late Cretaceous epoch or Upper Cretaceous series, the Cretaceous period or system, and of the Mesozoic era or erathem. It spanned from 70.6 ± 0.6 Ma to 65.5 ± 0.3 Ma...

, about 71 to 66 million years ago) of Madagascar
Madagascar
The Republic of Madagascar is an island country located in the Indian Ocean off the southeastern coast of Africa...

. 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 the Gondwanatheria
Gondwanatheria
Gondwanatheria is an extinct group of mammals that lived during the Upper Cretaceous through the Eocene in the Southern Hemisphere, including Antarctica...

, an enigmatic group with unclear phylogenetic relationships, and within Gondwanatheria as a member of the family Sudamericidae
Sudamericidae
Sudamericidae is a family of gondwanathere mammals that lived during the late Cretaceous to Eocene. Its members include Lavanify from the Cretaceous of Madagascar, Bharattherium from the Cretaceous of India, Gondwanatherium from the Cretaceous of Argentina, Sudamerica from the Paleocene of...

. Lavanify is most closely related to the Indian Bharattherium
Bharattherium
Bharattherium is a mammal that lived in India during the Maastrichtian . The genus has a single species, Bharattherium bonapartei. It is part of the gondwanathere family Sudamericidae, which is also found in Madagascar and South America during the latest Cretaceous...

; the South American Sudamerica
Sudamerica
Sudamerica, literally "South America" in Spanish, is a genus of mammal from the extinct suborder Gondwanatheria that lived in Patagonia, South America during the Paleocene, just after the end of the "Age of Dinosaurs"....

and Gondwanatherium
Gondwanatherium
Gondwanatherium is a genus of mammal from the extinct suborder Gondwanatheria that lived in Patagonia, South America during the "Age of Dinosaurs", specifically the Upper Cretaceous....

are more distantly related. Gondwanatheres probably ate hard plant material.

Lavanify had high-crowned
Crown (tooth)
In dentistry, crown refers to the anatomical area of teeth, usually covered by enamel. The crown is usually visible in the mouth after developing below the gingiva and then erupting into place.-References:...

, curved teeth. One of the two teeth is 11.2 mm high and shows a deep furrow and, in the middle of the crown, a V-shaped area that consists of dentine. 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 crystalls) between the prisms (bundles of hydroxyapatite crystalls) of the enamel
Tooth enamel
Tooth enamel, along with dentin, cementum, and dental pulp is one of the four major tissues that make up the tooth in vertebrates. It is the hardest and most highly mineralized substance in the human body. Tooth enamel is also found in the dermal denticles of sharks...

, and 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 State University of New York
State University of New York
The State University of New York, abbreviated SUNY , is a system of public institutions of higher education in New York, United States. It is the largest comprehensive system of universities, colleges, and community colleges in the United States, with a total enrollment of 465,000 students, plus...

, Stony Brook University, and the University of Antananarivo
University of Antananarivo
University of Antananarivo is the primary public university of Madagascar, located in the capital Antananarivo.The school traces its founding to 16 December 1955 and the formation of the Institute for Advanced Studies in Antananarivo. It quickly established itself as the main center for higher...

 to the late Cretaceous
Late Cretaceous
The Late Cretaceous is the younger of two epochs into which the Cretaceous period is divided in the geologic timescale. Rock strata from this epoch form the Upper Cretaceous series...

 (mostly Maastrichtian
Maastrichtian
The Maastrichtian is, in the ICS' geologic timescale, the latest age or upper stage of the Late Cretaceous epoch or Upper Cretaceous series, the Cretaceous period or system, and of the Mesozoic era or erathem. It spanned from 70.6 ± 0.6 Ma to 65.5 ± 0.3 Ma...

, about 71 to 66 million years ago [mya]) Maevarano Formation
Maevarano Formation
The Maevarano Formation is an Upper Cretaceous sedimentary rock formation found in the Mahajanga Province of northwestern Madagascar. It is most likely Maastrichtian in age, and records a seasonal, semiarid environment with rivers that had greatly varying discharges...

 of northwestern Madagascar. The two teeth were found in different sites in a white sandstone
Sandstone
Sandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains.Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any colour, but the most common colours are tan, brown, yellow,...

 unit of the Maevarano Formation near the village of Berivotra and have been deposited in the collections of the University of Antananarivo (specimen UA 8653) and Field Museum of Natural History
Field Museum of Natural History
The Field Museum of Natural History is located in Chicago, Illinois, USA. It sits on Lake Shore Drive next to Lake Michigan, part of a scenic complex known as the Museum Campus Chicago...

 (specimen FMNH PM 59520). David Krause and colleagues described Lavanify and a sudamericid
Sudamericidae
Sudamericidae is a family of gondwanathere mammals that lived during the late Cretaceous to Eocene. Its members include Lavanify from the Cretaceous of Madagascar, Bharattherium from the Cretaceous of India, Gondwanatherium from the Cretaceous of Argentina, Sudamerica from the Paleocene of...

 from India, which they did not name, in a 1997 paper in Nature
Nature (journal)
Nature, first published on 4 November 1869, is ranked the world's most cited interdisciplinary scientific journal by the Science Edition of the 2010 Journal Citation Reports...

. These were the first gondwanathere mammals to be found outside of Argentina and provided evidence that the mammal faunas of the different Gondwana
Gondwana
In paleogeography, Gondwana , originally Gondwanaland, was the southernmost of two supercontinents that later became parts of the Pangaea supercontinent. It existed from approximately 510 to 180 million years ago . Gondwana is believed to have sutured between ca. 570 and 510 Mya,...

n (southern) continents were similar to each other. The generic name, Lavanify, means "long tooth" and the specific name, miolaka, means "curved" in Malagasy
Malagasy language
Malagasy is the national language of Madagascar, a member of the Austronesian family of languages. Most people in Madagascar speak it as a first language as do some people of Malagasy descent elsewhere.-History:...

; both refer to the teeth's shape.

Gondwanatheres are a small group of mammals of uncertain phylogenetic affinities known from the late Cretaceous to the Eocene
Eocene
The Eocene Epoch, lasting from about 56 to 34 million years ago , is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Palaeocene Epoch to the beginning of the Oligocene Epoch. The start of the...

 (~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
The superorder Xenarthra is a group of placental mammals , existent today only in the Americas and represented by anteaters, tree sloths, and armadillos. The origins of the order can be traced back as far as the Paleogene in South America...

ns—part of the same group as living sloth
Sloth
Sloths are the six species of medium-sized mammals belonging to the families Megalonychidae and Bradypodidae , part of the order Pilosa and therefore related to armadillos and anteaters, which sport a similar set of specialized claws.They are arboreal residents of the jungles of Central and South...

s, armadillo
Armadillo
Armadillos are New World placental mammals, known for having a leathery armor shell. Dasypodidae is the only surviving family in the order Cingulata, part of the superorder Xenarthra along with the anteaters and sloths. The word armadillo is Spanish for "little armored one"...

s, and anteater
Anteater
Anteaters, also known as antbear, are the four mammal species of the suborder Vermilingua commonly known for eating ants and termites. Together with the sloths, they compose the order Pilosa...

s—but later workers have favored affinities with multituberculates (a diverse group of fossil mammals) or left the relationships of the gondwanatheres open. The group comprises two families
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

. The family Ferugliotheriidae
Ferugliotheriidae
Ferugliotheriidae is one of two 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 mammalian order. The best-known representative of...

, whose members had low-crowned teeth, occurs in the Campanian
Campanian
The Campanian is, in the ICS' geologic timescale, the fifth of six ages of the Late Cretaceous epoch . The Campanian spans the time from 83.5 ± 0.7 Ma to 70.6 ± 0.6 Ma ...

 (~84–71 mya) to Maastrichtian of Argentina. All other gondwanatheres, including Lavanify, are placed in the Sudamericidae, which have high-crowned (hypsodont
Hypsodont
Hypsodont dentition is characterized by high-crowned teeth and enamel which extends past the gum line. This provides extra material for wear and tear. Some examples of animals with hypsodont dentition are cows, horses and deer; all animals that feed on gritty, fibrous material. The opposite...

) teeth. These include Gondwanatherium
Gondwanatherium
Gondwanatherium is a genus of mammal from the extinct suborder Gondwanatheria that lived in Patagonia, South America during the "Age of Dinosaurs", specifically the Upper Cretaceous....

from the Campanian and Maastrichtian of Argentina; Sudamerica
Sudamerica
Sudamerica, literally "South America" in Spanish, is a genus of mammal from the extinct suborder Gondwanatheria that lived in Patagonia, South America during the Paleocene, just after the end of the "Age of Dinosaurs"....

from the Paleocene
Paleocene
The Paleocene or Palaeocene, the "early recent", is a geologic epoch that lasted from about . It is the first epoch of the Palaeogene Period in the modern Cenozoic Era...

 (~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
TNM 02067
TNM 02067 is a fragmentary fossil dentary from the Cretaceous of Tanzania. The short, deep bone is about long, but the back part is broken off. It contains a large, forward-inclined incisor with a root that extends deep into the jaw, separated by a diastema from five cheekteeth...

, 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
Bharattherium is a mammal that lived in India during the Maastrichtian . The genus has a single species, Bharattherium bonapartei. It is part of the gondwanathere family Sudamericidae, which is also found in Madagascar and South America during the latest Cretaceous...

respectively; as the latter name was published first, it is the correct name for this genus according to the Principle of Priority
Principle of Priority
thumb|270px|Boa manditraIn zoology, the scientific study of animals, the Principle of Priority is one of the guiding principles of the International Code of Zoological Nomenclature, defined by Article 23....

. Gondwanatheres have been interpreted as feeding on roots, bark, and abrasive vegetation or as the earliest grass
Grass
Grasses, or more technically graminoids, are monocotyledonous, usually herbaceous plants with narrow leaves growing from the base. They include the "true grasses", of the Poaceae family, as well as the sedges and the rushes . The true grasses include cereals, bamboo and the grasses of lawns ...

-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
Molar (tooth)
Molars are the rearmost and most complicated kind of tooth in most mammals. In many mammals they grind food; hence the Latin name mola, "millstone"....

, UA 8699, may be of a marsupial
Marsupial
Marsupials are an infraclass of mammals, characterized by giving birth to relatively undeveloped young. Close to 70% of the 334 extant species occur in Australia, New Guinea, and nearby islands, with the remaining 100 found in the Americas, primarily in South America, but with thirteen in Central...

 or a placental and a molar fragment is referable to Multituberculata
Multituberculata
The Multituberculata were a group of rodent-like mammals that existed for approximately one hundred and twenty million years—the longest fossil history of any mammal lineage—but were eventually outcompeted by rodents, becoming extinct during the early Oligocene. At least 200 species are...

. 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). The fauna also contains crocodyliforms, dinosaur
Dinosaur
Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...

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
Premolar
The premolar teeth or bicuspids are transitional teeth located between the canine and molar teeth. In humans, there are two premolars per quadrant, making eight premolars total in the mouth. They have at least two cusps. Premolars can be considered as a 'transitional tooth' during chewing, or...

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 (ridges and grooves arranged in a transverse, wave-like pattern).

UA 8653, the holotype
Holotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...

, 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
Occlusion (dentistry)
Occlusion, in a dental context, means simply the contact between teeth. More technically, it is the relationship between the maxillary and mandibular teeth when they approach each other, as occurs during chewing or at rest....

 (chewing) surface is worn flat and contains a V-shaped island of dentine surrounded by enamel
Tooth enamel
Tooth enamel, along with dentin, cementum, and dental pulp is one of the four major tissues that make up the tooth in vertebrates. It is the hardest and most highly mineralized substance in the human body. Tooth enamel is also found in the dermal denticles of sharks...

. One side of the crown lacks enamel. Between the two arms of the V, at the lingual (inner) side of the tooth, is a furrow filled with cementum
Cementum
Cementum is a specialized calcified substance covering the root of a tooth. Cementum is excreted by cells called cementoblasts within the root of the tooth and is thickest at the root apex. These cementoblasts develop from undifferentiated mesenchymal cells in the connective tissue of the dental...

, 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).

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.

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. 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
Synapomorphy
In cladistics, a synapomorphy or synapomorphic character is a trait that is shared by two or more taxa and their most recent common ancestor, whose ancestor in turn does not possess the trait. A synapomorphy is thus an apomorphy visible in multiple taxa, where the trait in question originates in...

 (shared derived traits) for the Bharattherium-Lavanify clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...

. 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
Autapomorphy
In cladistics, an autapomorphy is a distinctive anatomical feature, known as a derived trait, that is unique to a given terminal group. That is, it is found only in one member of a clade, but not found in any others or outgroup taxa, not even those most closely related to the group...

(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. They also mentioned the presence of a furrow and infundibulum as shared traits.

Literature cited

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