Glossary of mammalian dental topography

Many different terms have been proposed for features of the tooth crown in mammals.

The structures within the molars receive different names according to their position and morphology. This nomenclature was developed by Henry Fairfield Osborn in 1907 and is, although with many variations, the one that continues today.[1][2][3]

  • The suffix "-cones /-conids" (upper molar/lower molar) is added to the main cusps: Paraconus, Metaconus, Protoconus and Hypoconus on the upper molar, and Paraconid, Metaconid, Protoconid, Hypoconid and Entoconid on the lower molar. This name is used for both bunodont and selenodont molars, that is, as many for "buno" pillar-like cusps as for "selenes" crescent-like cusps.
  • The suffix "-conule /-conulid" (upper molar/lower molar) is added to the secondary cusps. For example, Metaconule, Hypoconulid.
  • The suffix "-style/-stylid" (upper molar/lower molar) is added to the peripheral cusps that are found in the cornices or cingulus of the tooth. These cusps are traditionally named according to their proximity to the main cusps, although some anatomists prefer to name them according to their position on the tooth.
  • The suffix "-loph/-lophid" (upper molar/lower molar) is added to the crests that join cusps together. They include in the name one the cusps involved. For example, the hypolophid is the ridge that unites the hypoconid with the entoconid. These ridges often have secondary ridges: the secondary crest of the ectoloph is called crista; antecrochet to that of the protoloph, and crochet to that of the metaloph.
  • The suffix "-crista / -cristid" (upper molar / lower molar) is used for the ridges that come out of the cusps but do not connect them with other cusps. It is also used to name the edges of selenes.
  • To the structures in the lingual part of the molar, the prefix "ento-" ("internal") is often added, while those of the lingual part are added the prefix "ecto-" ("external"). the mesial part of the molar is often added the prefix "pre-" (from "previous") while those of the distal part are added the prefix "post-" ("posterior"). The mesial part is that which is towards the incisors.
  • The suffix "-flexus / -flexid" (upper molar / lower molar) is used for the open valleys in the occlusal surfaces of the hypsodont teeth. When this valleys are enclosed, they are called fossetes/fossetids (upper molar / lower molar). Sometimes they are used also for the folds of the teeth, although the proper name for the folds is sulcus (pl. sulci).
  • The cusp prefixes "para-", "meta-", "proto-", "hypo-", etc., are related to the succession and position of the cusps according to the ancient tritubercular theory of the evolution of molars from Cope and Osborn. Although this theory has lost its validity, they continue to use the names for the description of the molars. The prefix "proto" referred to the original cusp which would be homologous to a single cusp tooth according to Osborn, and would be the first cusp to appear not only in evolution but in development.[1] This was criticized early by studies of embryology where it was shown that the first cusp in the embryonic development of the upper molars was the paraconus. Later this was shown to be variable and the first cusp to appear in ontogeny would not be related to the evolution of the tooth.[2]

CRICETIDAE MOLAR TEETH NOMENCLATURE AFTER REIG(1977).[4]

Cricetidae molar teeth nomenclature after Reig, 1977.

Upper teeth

NameNomenclature term is used inDefinitionCommentsImage
Anterolingual conuleReig (1977)[4] A conule on the lingual side of an anterocone divided by an anteromedian flexus or fossette
Anteromedian flexusReig (1977)[4]A longitudinal flexus dividing the anterocone into anterolabial and anterolingual conules
Anterolabial conuleReig (1977)[4]A conule on the labial side of an anterocone divided by an anteromedian flexus or fossette
AnteroconeReig (1977)[4]A cusp at the front of the tooth that may be divided into anterolabial and anterolingual conules
ProtostyleReig (1977)[4]A style in front of the protocone, in the protoflexus
ProtoflexusReig (1977)[4]A flexus between the protocone and the anterolingual conule
Anterior mureReig (1977)[4]A crest connecting the anterocone to the protocone
ProtoconeReig (1977)[4]One of the main cusps, at the anterolingual side
EnterostyleReig (1977)[4]A style between the protocone and the hypocone, in the hypoflexus
EnterolophReig (1977)[4]A crest connecting the enterostyle to the mesocone
HypoflexusReig (1977)[4]A flexus between the protocone and the hypocone
MesoconeReig (1977)[4]A conule in the median mure where the mesoloph is attached to it
Median mureReig (1977)[4]A crest connecting the protocone/paracone to the hypocone/metacone
HypoconeReig (1977)[4]One of the main cusps, at the posterolingual side
ProcingulumReig (1977)[4]The front part of the tooth, before the anterior mure
AnteroflexusReig (1977)[4]A flexus between the anteroloph and the anterolabial conule
AnterolophReig (1977)[4]A crest between the paracone and the anterolabial conule that may be connecting to a parastyle
ParastyleReig (1977)[4]A style in front of the paracone
ParaflexusReig (1977)[4]A flexus in front of the paracone
ProtolophuleReig (1977)[4]A small crest in the paraflexus, connected to the protocone
ParalophReig (1977)[4]A crest attaching the paracone to the protocone or the median mure
ParaconeReig (1977)[4]One of the main cusps, at the anterolabial side
ParalophuleReig (1977)[4]A small crest attached to the back side of the paracone
MesoflexusReig (1977)[4]A flexus between the mesoloph and the paracone
MesostyleReig (1977)[4]A style at the labial margin between the paracone and metacone
MesolophReig (1977)[4]A crest in front of the metaflexus, connected to the median mure
MetaflexusReig (1977)[4]A flexus in front of the metacone
MetalophuleReig (1977)[4]A small crest attached to the front side of the metacone
MetaconeReig (1977)[4]One of the main cusps, at the posterolabial side
MetalophReig (1977)[4]A crest attaching the paracone to the hypocone
PosteroflexusReig (1977)[4]A flexus between the posteroloph and the metacone
PosterostyleReig (1977)[4]A crest on the posterolabial corner of the molar
PosterolophReig (1977)[4]A crest at the back of the molar, connected to the hypocone

Lower teeth

NameNomenclature term is used inDefinitionCommentsImage
Anterolingual conulidReig (1977)[4]A conulid on the lingual side of an anteroconid divided by an anteromedian flexid or fossettid
Anteromedian flexidReig (1977)[4]A longitudinal flexid dividing the anteroconid into anterolabial and anterolingual conules
Anterolabial conulidReig (1977)[4]A conulid on the labial side of an anteroconid divided by an anteromedian flexid or fossettid
AnteroconidReig (1977)[4]A cusp at the front of the tooth that may be divided into anterolabial and anterolingual conulids
Anterolabial cingulumReig (1977)[4]A crest before the protoconid and protoflexid
ProtostylidReig (1977)[4]A stylid in front of the protoconid, in the protoflexid
ProtoflexidReig (1977)[4]A flexid between the protoconid and the anterolabial conulid
Anterior muridReig (1977)[4]A crest connecting the anteroconid to the protoconid
ProtoconidReig (1977)[4]One of the main cusps, at the anterolabial side
EctostylidReig (1977)[4]A stylid between the protoconid and the hypoconid, in the hypoflexid
EctolophidReig (1977)[4]A crest connecting the ectostylid to the mesoconid
HypoflexidReig (1977)[4]A flexid between the protoconid and the hypoconid
MesoconidReig (1977)[4]A conulid in the median murid where the mesolophid is attached to it
Median muridReig (1977)[4]A crest connecting the protoconid/metaconid to the hypoconid/entoconid
HypoconidReig (1977)[4]One of the main cusps, at the posterolabial side
ProcingulumReig (1977)[4]The front part of the tooth, before the anterior murid
AnteroflexidReig (1977)[4]A flexid between the anterolophid and the anterolingual conulid
AnterolophidReig (1977)[4]A crest between the metaconid and the anterolabial conulid that may be connecting to a metastylid
MetastylidReig (1977)[4]A stylid in front of the metaconid
MetaflexidReig (1977)[4]A flexid in front of the metaconid
ProtolophulidReig (1977)[4]A small crest in the mesoflexid, connected to the protoconid
MetalophidReig (1977)[4]A crest attaching the metaconid to the protoconid or the anterior murid
MetaconidReig (1977)[4]One of the main cusps, at the anterolingual side
MetalophulidReig (1977)[4]A small crest attached to the back side of the metaconid
MesoflexidReig (1977)[4]A flexid between the mesolophid and the paraconid
MesostylidReig (1977)[4]A stylid at the labial margin between the metaconid and entoconid
MesolophidReig (1977)[4]A crest in front of the entoflexid, connected to the median murid
EntoflexidReig (1977)[4]A flexid in front of the entoconid
EntolophulidReig (1977)[4]A small crest attached to the front side of the entoconid
EntoconidReig (1977)[4]One of the main cusps, at the posterolingual side
EntolophidReig (1977)[4]A crest attaching the entoconid to the hypoconid or median murid
PosteroflexidReig (1977)[4]A flexid between the posterolophid and the metaconid
HypolophulidReig (1977)[4]A small crest in the posteroflexid attached to the posterolophid
PosterostylidReig (1977)[4]A crest on the posterolingual corner of the molar
PosterolophidReig (1977)[4]A crest at the back of the molar, connected to the hypoconid

See also

References

  1. Osborn, Henry Fairfield, 1857–1935. (1907). Evolution of mammalian molar teeth to and from the triangular type: including collected and revised researches on trituberculy, and new sections on the forms and homologies of the molar teeth in the different orders of mammals. Kessinger Publishing. ISBN 978-1-4368-4090-3. OCLC 810943856.{{cite book}}: CS1 maint: multiple names: authors list (link)
  2. MacCord, Katherine (2017). Development, evolution, and teeth: how we came to explain the morphological evolution of the mammalian dentition. Arizona State University.
  3. Szalay, Frederick S. (1969). "Mixodectidae, Microsyopidae, and the insectivore-primate transition". Bulletin of the American Museum of Natural History. 140 4: 193–330. hdl:2246/1130.
  4. Reig, Osvaldo A. (2009). "A proposed unified nomenclature for the enamelled components of the molar teeth of the Cricetidae (Rodentia)". Journal of Zoology. 181 (2): 227–241. doi:10.1111/j.1469-7998.1977.tb03238.x. ISSN 0952-8369.
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