Cynelos macrodon ( Savage, 1965 )
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publication ID |
https://doi.org/ 10.4202/app.00794.2020 |
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persistent identifier |
https://treatment.plazi.org/id/3F6287C1-FFB1-FF93-CA67-AA79FBCAEDEE |
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treatment provided by |
Felipe |
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scientific name |
Cynelos macrodon ( Savage, 1965 ) |
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Cynelos macrodon ( Savage, 1965)
Fig. 4 View Fig , Tables 3, 4.
Holotype: Left M 1 ( NHM M 19086 ); Savage (1965).
Type locality: Site 31, Rusinga Island, Kiahera Formation, Kenya; Early Miocene.
Type horizon: Early Miocene.
Material.—KNMWS 49476, right m2; KNMWS 49485, left M1; KNMWS 65315, left M3; KNMWS 65407, right m2; KNMWS 65418, right m2; KNMWS 65465, left m2. All from Buluk, east of Lake Turkana, Kenya; lower section of the Buluk Member, Bakate Formation, uppermost lower Miocene.
Diagnosis.—As in Morlo et al. (2019). See also Savage (1965), Morales et al. (2016), and Adrian et al. (2018).
Description.—The protoconid, metaconid, and hypoconid of the m 2 specimen KNMWS 49476 ( Fig. 4F View Fig ) are heavily abraded, but there appears to be no notch separating the metaconid from the anterior cingulid. The base of the tooth is enlarged at its posterobuccal corner, and the tooth is slightly longer than the m2 of Cynelos anubisi Morlo, Miller, and ElBarkooky, 2007 , from the lower Miocene of North Africa (Morales et al. 2010; Morlo et al. 2019), and Cynelos cf. macrodon from the middle Miocene Muruyur Formation, Kenya ( Morlo et al. 2019). The talonid of the Buluk specimen is also wider than that observed for the similar sized Cynelos ginsburgi (Morales, Pickford, Soria, and Fraile, 1998) , and the hypoconid is smaller. The morphology of three other second lower molars ( Fig. 4A–D View Fig ) of this species from Buluk are similar in morphology to KNMWS 49476, except that they are smaller in size, with the smallest specimen, KNMWS 65418, being about 20% shorter and 13% narrower than KNMWS 49476 ( Table 4).
The M1 KNMWS 49485 ( Fig. 4E View Fig ) is close in morphology to the holotype of Cynelos macrodon from Rusinga Island, especially in their shared triangular occlusal outline Savage 1965; Morales et al. 2016: fig. 9/2A). The cusps of the trigon are heavily abraded and the same is true for the hypocone. As in the holotype, the hypoconule and entoconule are not clearly demarcated, a feature that separates C. macrodon from C. ginsburgi . The lingual cingulum is smaller than in the holotype.
The M3 KNMWS 65315 ( Fig. 4F View Fig ) is the first recovered M3 of C. macrodon . Morphologically, the tooth closely resembles the M3 of the larger species of Cynelos present at Buluk, but KNMWS 65315 is much smaller.
Remarks.—Although the contribution to the C. macrodon hypodigm from Buluk consists of only seven teeth, the collection represents the largest sample of C. macrodon described from a single locality. The four m 2 specimens confirm the morphology of this tooth, as suggested by the tentative assignment of an m2 from the middle Miocene Muruyur Formation, Kenya, to C. cf. macrodon ( Morlo et al. 2019) . However, the Buluk m2s differ from the middle Miocene specimen of C. cf. macrodon in being slightly longer anteroposteriorly, and in having a smaller hypoconid. The four Buluk m 2 specimens also vary in absolute size as well as in relative length. Given the general lack of comparable specimens from other sites, it is not clear how to interpret this large size variation, as such variation has only been documented previously for the upper canines of Cynelos ( Peigné and Heizmann 2003) .
Stratigraphic and geographic range.—Lower and middle Miocene of East Africa.
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