Cachiyacuy kummeli Antoine et al., 2012
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publication ID |
https://doi.org/ 10.26879/742 |
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publication LSID |
lsid:zoobank.org:pub:540D23AA-F705-4A05-8E10-FADAD3356D9C |
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persistent identifier |
https://treatment.plazi.org/id/03A587B4-E52A-AC1B-FC71-D34BFBB116FF |
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treatment provided by |
Felipe |
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scientific name |
Cachiyacuy kummeli Antoine et al., 2012 |
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Cachiyacuy kummeli Antoine et al., 2012
Figure 4.9 View FIGURE 4 -13, Appendix 3
Referred material. In addition to the holotype ( MUSM 1882 , left M1; in Antoine et al., 2012, figure 2m) - MUSM 1888 (in Antoine et al., 2012, figure 2s) and 2762–2763 ( Figure 4.9 View FIGURE 4 ), left dp4s ; MUSM 2764–2765 , right dp4s ; MUSM 2766 , left p4 ( Figure 4.10 View FIGURE 4 ) ; MUSM 2767–2768 , left m1s ; MUSM 1887 (in Antoine et al., 2012, figure 2r) and 2769– 2771, right m1s ; MUSM 2772 , left m2 ; MUSM 1886 (in Antoine et al., 2012, figure 2q) and 2773–2775, right m2s ; MUSM 2776 , right m2 ?; MUSM 2777– 2779 , left m3s ; MUSM 1885 (in Antoine et al., 2012, figure 2p) and 2780–2781 ( Figure 4.11 View FIGURE 4 ), right m3s ; MUSM 2783 , left P4 ; MUSM 1881 , right P4 (in Antoine et al., 2012, figure 2l) ; MUSM 2784 , right M1 or M2 ; MUSM 2785 , left M1 ( Figure 4.12 View FIGURE 4 ) ; MUSM 1883 (in Antoine et al., 2012, figure 2n) and 2786 ( Figure 4.13 View FIGURE 4 ), left M2s ; MUSM 1884 , left M3 (in Antoine et al., 2012, figure 2o) .
Type locality. Contamana CTA-27, Loreto Department, Peru .
Formation and age. Pozo Formation, lower member, late middle Eocene ( Antoine et al., 2012, 2016).
Diagnosis sensu Antoine et al. (2012, p. 1321). Cachiyacuy kummeli (body mass estimated at 30– 40 g) is ~30% smaller than C. contamanensis . The molars have slightly thinner transverse crests and the cusp(id)s are more salient than in C. contamanensis .
Description. The occlusal morphology of the upper and lower teeth referred to Cachiyacuy kummeli is basically similar to that of the teeth of C. contamanensis . C. kummeli differs substantially from C. contamanensis in being ~30% smaller, and in having molars with transverse crests slightly thinner and cusp(id)s more salient. The dp4s of C. kummeli also differ from those referred to C. contamanensis , notably in the distal region of the talonid, which shows a posterolophid less curved ( Figure 4.9 View FIGURE 4 ). The unique p4 of C. kummeli (MUSM 2766; Figure 4.10 View FIGURE 4 ) has neither mesoconid, nor mesolophid nor neocristulid(s) between the second transverse cristid and the hypolophid, contrary to some specimens of C. contamanensis ( Figure 7 View FIGURE 7 ). On the lower molars, especially on m1s, the mesoconid is more frequently absent and the mesostylid is often less indistinct, being entirely subsumed in the strong posterior arm of the metaconid ( Figure 4.11 View FIGURE 4 ). The second transverse cristid, which could appear as a long and complete metalophulid II, also seems to be a composite of two short cristids (posterior arm of the protoconid and neomesolophid) that merge together medially. The accessory enamel cristids are rarer and less long. Like in C. contamanensis , the metaloph on upper molars can be absent (MUSM 2785; Figure 4.12 View FIGURE 4 ). On M2s of C. kummeli (MUSM 1883 and 2786; Figure 4.13 View FIGURE 4 ), the metaloph is less developed than that of M2s of C. contamanensis . On MUSM 1883, the metaloph corresponds to a tiny low crestule on the mesial slope of the posteroloph without any connection with the third transverse crest, the anterior arm of the hypocone or the posteroloph. MUSM 2786 ( Figure 4.13 View FIGURE 4 ) shows an unusual crest, which is mesiolingually directed, and located between the third transverse crest and the posteroloph. That crest is composed of two merged crestules, one stemming from the posteroloph to the other from the third transverse crest. These crestules may be remanent connections of the metaloph to the third transverse crest and posteroloph.
Comparisons. Cachiyacuy differs from Eoincamys from Santa Rosa ( Peru,?late Eocene/early Oligocene; Frailey and Campbell, 2004) and Incamys from Salla ( Bolivia, late Oligocene; Hoffstetter and Lavocat, 1970; Lavocat, 1976) in having brachydont instead of hypsodont teeth, pentalophodont instead of tetralophodont upper molars, and in developing thinner and transverse instead of strong and oblique crests, and in the absence of a taeniodont pattern on both upper and lower teeth (i.e., lingual protoloph and anterior arm of hypoconid lacking). Contrary to Eobranisamys , Branisamys , and Canaanimys , Cachiyacuy does not exhibit a taeniodont pattern of the upper molars due to the presence of a strong lingual protoloph ( Hoffstetter and Lavocat, 1970; Lavocat, 1976; Frailey and Campbell, 2004). Cachiyacuy differs from Eobranisamys , Branisamys , Eosallamys , Sallamys , Eoespina , Eosachacui , Vallehermosomys Vucetich et al., 2010 and Draconomys in showing long metalophs neither backwardly directed nor connected to the posteroloph, but transverse (lingually directed) and without lingual connection instead. Accessory, thin and short enamel crests may connect the metaloph to the posteroloph and/ or to the central transverse crest. However, on some upper molars of Eosallamys (LACM 143422, 143363, 143376, 143380; in Frailey and Campbell, 2004, p. 120–122), the metaloph can be connected to the central transverse crest via a secondary crestule. However, in Cachiyacuy , the crests and cristids are slenderer, and they show a thinner enamel thickness than in Eosallamys . In Cachiyacuy (especially in C. contamanensis ), lower molars have a complete second transverse cristid (even if it is composed of two parts) and accessory cristulids within the anterofossettid. In contrast, in Draconomys there is no accessory cristulid within the anterofossettid, and the second transverse cristid is always interrupted before to reach the mesostylid (i.e., absence of neomesolophid in this taxon), being only composed of a long posterior arm of the protoconid. Besides, Cachiyacuy differs from Draconomys in having transverse crests on its upper molars, which are labiolingually shorter. Finally, Cachiyacuy differs from Sallamys in having a second composite transverse cristid more complete on lower molars.
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