Apatemys rodens Troxell, 1923b
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publication ID |
https://doi.org/ 10.26879/720 |
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publication LSID |
lsid:zoobank.org:pub:341D2FE3-977D-4C82-A337-C681FC00C53A |
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persistent identifier |
https://treatment.plazi.org/id/BB4187B4-FF9E-FF82-FC4F-7680FAEDF9CA |
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treatment provided by |
Felipe |
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scientific name |
Apatemys rodens Troxell, 1923b |
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Apatemys rodens Troxell, 1923b
Figure 2.7-12 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 6 View FIGURE 7 View FIGURE 8 View FIGURE 9 View FIGURE 10 View FIGURE 11 View FIGURE 12 , Table 1
Referred specimens. From SDSNH Locality 5841: partial LM3, SDSNH 110342. From UCM Locality 92189: LM1, UCM 68580; LM3, UCM
68970; Rm3s, UCM 95801, 95805; Lm3, UCM 66324.
Description. All of the referred teeth are very large compared to those of other species of Apatemys ( Marsh, 1872b; Troxell, 1923b; Matthew, 1921, 1929; Jepsen, 1934; Gazin, 1958; Robinson, 1966b; West, 1973b). The M1 is in early wear. Its metacone is larger than the paracone with its apex positioned slightly more lingually than that of the metacone. The protocone is large and positioned anteriorly, just posterior of the paracone apex. The hypocone is robust. A distinct parastyle is present on the anterolabial corner of the stylar shelf and the labial border of stylar shelf is relatively straight. The postmetacrista extends posteriorly from the metacone apex to terminate at an indistinct metastyle at the posterolabial corner of the stylar shelf. The anterior and posterior cingula are weak.
The M3 is transversely expanded, that is its length is significantly narrower than its width. The paracone is slightly larger than the metacone and positioned slightly more labially. The protocone is large and positioned anteriorly, below the paracone apex. The hypocone is weakly developed as a bulge on the posterior cingulum. The parastylar lobe is robust, elongated, and projects nearly straight labially. The parastyle is a moderately distinct cusp, positioned near the central, labial edge of the parastylar lobe. The anterior cingulum is weak. A distinct metastyle is lacking.
Three m3s are identified. One is complete, whereas the other two are missing portions of the trigonids. They exhibit a trapezoidal trigonid occlusal outline with a well-developed accessory cuspid positioned at the anterolabial corner of the trigonid. All of the trigonid primary cusps (paraconid, metaconid, and protoconid) are robust. The talonid has a relatively shallow basin and is wide anteriorly, but tapers posteriorly, giving it a somewhat tear-drop occlusal outline. The entoconid is small, but distinct. The hypoconid is expressed as a weak bulge along the posterolabial edge of the talonid, and the cristid obliqua extends anteriorly from it to join the posterior wall of the trigonid labial of the notch between the protoconid and metaconid.
Remarks. A second group of very large Apatemys teeth are present at UCM Locality 92189 and SDSNH Locality 6242 ( Figure 2.7-12 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 6 View FIGURE 7 View FIGURE 8 View FIGURE 9 View FIGURE 10 View FIGURE 11 View FIGURE 12 ) that exhibit some minor occlusal differences from those referred to A. bellulus (see above). These teeth are within the size range of those of the A. rodens ( Troxell, 1923b; West, 1973b) and are referred to the species.
Grandorder LIPOTYPHLA Haeckel, 1866
Order ERINACEOMORPHA Gregory, 1910
Family SESPEDECTIDAE Novacek, 1985
Subfamily SCENOPAGINAE Novacek, 1985
Genus SCENOPAGUS McKenna and Simpson, 1959
Scenopagus priscus Marsh, 1872b
Figure 3.9-11 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 6 View FIGURE 7 View FIGURE 8 View FIGURE 9 View FIGURE 10 View FIGURE 11 , Table 2
Referred specimens. From UCM Locality 92189: partial Rm1 or 2, UCM 95683. From SDSNH Locality 5841: Rm3, SDSNH 110345.
Description. The m3 and the m1 or 2 have similar occlusal morphologies, except that the m3 talonid is much narrower relative to the trigonid width, and its trigonid is slightly more anteroposteriorly compressed between the metaconid and paracristid. The talonids of the lower molars are about half the height of the trigonids. The metaconid and protoconid are robust and connected by a postprotocristid that is notched centrally and lower in height. The paracristid is lower in height than the metaconid and protoconid, and extends lingually from the anterolabial corner of the protoconid to terminate near the anterior base of the metaconid. A distinct paraconid is lacking at the lingual terminus of the paracristid. The talonid consists of a robust entoconid and hypoconid, and a distinct, centrally positioned hypoconulid. The cristid obliqua extends from the hypoconid to terminate on the posterior wall of the trigonid at a point just slightly labial of the central notch of the postprotocristid. The anterior cingulid is moderately robust.
Remarks. Four species of Scenopagus are recognized from the Bridger Formation; S. priscus ( Marsh, 1872b) , S. curtidens ( Marsh, 1872b) , S. edenensis ( McGrew, 1959) , and S. mcgrewi McKenna and Simpson, 1959 . They are differentiated primarily by size and slight differences in the occlusal morphologies of M1-2 and p4 ( McGrew, 1959; Robinson, 1966a; McKenna and Simpson, 1959; McGrew and Sullivan, 1970; West, 1973a; Krishtalka, 1975, 1976a; Gunnell et al., 2008b). The two molars from the TBM agree well in size and occlusal morphology to those of Scenopagus priscus and are referred to the species.
| UCM |
University of Colorado Museum of Natural History |
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.