Trigonid


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Related to Trigonid: lophodont

Tri´go`nid


4.(Zool.) The cutting region of the crown of an upper molar, usually the anterior part. That of a lower molar is the Tri"go*nid ( ).
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References in periodicals archive ?
The trigonid and talonid are not equal in size; the trigonid is narrower than the talonid.
The paraconid was probably absent, although the state of preservation of the tooth does not permit a firm conclusion to be reached, although close inspection reveals that the trigonid valley was very small, tall and closed anteriorly.
m1 Antero-posterior Trigonid Talonid length width width PCS Sorex 1.
Description: The alveolar border of the teeth in the mandible (MBLUZ-P-3990, Figure 2f) is parallel with the inferior margin of the horizontal mandibular ramus; there is a relatively large mentonian foramen under the alveolus for the trigonid of mi, which extends anteriorly to the posterior part of the p4 talonid.
In Ankylodon and PTRM 1600, the metaconid is taller than the protoconid, connection of the cristid obliqua is buccal to the trigonid notch on the posterior margin of the trigonid and the specimen is larger than what is seen in the morphologically similar genus of Centetodon (5).
The trigonid is formed by subequal protoconid and metaconid with the protoconid slightly mesiad of the metaconid.
AL2-C, Alcoy-2C; AL2-D, Alcoy-2D; CLC, Calicasas; L, Length; LB2B, La Bullana 2B; LB3, La Bullana 3; MN, European Neogene land mammal Units; MNA, Mina; PUR, Purcal; SCSIE (UV), Servei Central de Suport a la Investigacio Experimental de la Universitat de Valencia; THC, Tollo de Chiclana; TLW, talonid width; TRW, trigonid width; W, Width.
Siamotragulus and Yunnanotherium differ from those of the studied samples in: more selenodont and hypsodont aspect premetacristid is well developed and closes the anterior side of the trigonid and a strong ectostylid (Thomas et al.
SDSM 82104 exhibits tall, conical cusps on the trigonid and a nearly identical size and morphology to the paratype specimen.
The lower carnassial suffers a marked reduction of the trigonid with regard to the talonid, which becomes much longer.
A deep median valley of the trigonid and the talonid and well developed hypoconulid development are the characteristic features of the studied specimens.