metaconid


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metaconid

[‚med·ə′kō·nəd]
(vertebrate zoology)
The posteroexternal cusp of a lower molar in mammals; corresponds with the metacone.
References in periodicals archive ?
The protoconid, metaconid, hypoconid and entoconid are organized into two distinct lobes with rounded corners separated from each other by a well-developed median valley.
At the antero-lingual side the metaconid is present having a thin and wrinkled enamel border.
Whereas M3 is a simple peglike tooth, m3 is slightly more complex, consisting of a reduced protoconid/ metaconid pair.
The p4 has a strongly developed posterior cuspid, m1 with strong and voluminous metaconid, m2 big with reduced to absent paraconid, narrow talonid almost completely occupied by the hypoconid.
The m1 has the labial and lingual cusps alignment alternate rather than opposite (as in the uppers), the metaconid is anteriorly positioned with respect to the protoconid, and the entoconid is anteriorly positioned with respect to the hypoconid.
Number of Occurrences Percentage Tooth First molar (P) 58 62.4 Fourth premolar (D) 18 19.4 Second molar (P) 14 15.1 Second premolar (D) 6 6.5 Third molar (P) 5 5.4 Third premolar (D) 5 5.4 Cusp Hypoconid 77 55.4 Protoconid 26 18.7 Metaconid 18 12.9 Entoconid 17 12.2 DISCUSSION
The PCS fossils agree with Soricini because the articular facets of the condyle are continuous, and m1-m2 each retain an entoconid crest that joins the entoconid to the metaconid.
The ml (MBLUZ-P-3.990, MBLUZ-P-5.896, MBLUZ-P-4.690; Table I; Figure 2f) has an anteriorly projected paraconid without enamel band; a metaconid enamel band is present; meta-entoconid fold shallow and reflected 45[degrees] anteromesialy; ento-hypoconid fold deeper and less inclined (85[degrees]) anteromesialy than meta-entoconid fold; hypoconid buccolingually broad, looks like a trigonid size; anterior facet of the trigonid convex; the lingual enamel band extends to the metaconid to the anterolingual side of the hypoconid, without covering it totally; buccal enamel fold deeper; buccal enamel band covering the anteromesial protoconid facet through posteromesial hypoconulid facet; hypoconid lingually projected; buccal enamel broader than lingual enamel.
Ankylodon is characterized by having moderate curvature of the trigonid, reduced paraconid, strongly convex buccal margin of the protoconid and metaconid, and boarder nature of the tooth when compared to Metacodon (1) all of which are seen in PTRM 1600.
Differs from Anthracokeryx, North American Bothriodon, Aepinacodon and Arretotherium, and Euro-American Elomeryx and African Bothriogenys in possessing a strong postprotocristid, tooth rows without significant diastemata between canine and P/1 and/or P/1-P/2, relatively simple P/2-P/3 with posterior cingulid slight, P/4 only slightly elaborated by a strong protocristid and lacking posterior cingulid, premolar lingual cingula absent, molar paracristid ending near base of metaconid and unconnected to anterior cingulum, and molar postentocristid weak ( H.
The species is characterized by a first lower molar with distinct lingual cusps (paraconulid) between the paraconid and metaconid.