Mammals from the mid-Cretaceous Khodzhakul Formation, Kyzylkum Desert, Uzbekistan

Averianov, Alexander O.; Archibald, J. David

doi:10.1016/j.cretres.2005.03.007

Cited by 45 publications

(39 citation statements)

References 24 publications

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“…Sasayamamylos also differs from Holoclemensia in having a non-molariform ultimate lower premolar [23], which also distinguishes Sasayamamylos from ausktribosphenids and some mid-Cretaceous eutherians, such as Bobolestes (including Otlestes, which is suggested as a junior synonym of Bobolestes by Averianov & Archibald [44]) and Montanalestes [33,39,40,[44][45][46]. On the other hand, Sasayamamylos shares a non-molariform ultimate lower premolar with Acristatherium, Eomaia, Juramaia, Prokennalestes and Sheikhdzheilia [3][4][5]14,44]; this characteristic is also thought to be plesiomorphic for eutherians.…”

Section: Comparison and Discussionmentioning

confidence: 99%

“…For example, S. kawaii does not have a Meckelian groove, which is present in Henosferus, ausktribosphenids, and some early eutherian mammals, such as in Bobolestes, Eomaia and Prokennalestes [4,14,39,40,42,44,45]; it shares the absence of this groove with Juramaia, Montanalestes and many Late Cretaceous eutherians [3,33]. The lower incisor count of S. kawaii is also probably apomorphic.…”

Section: Comparison and Discussionmentioning

confidence: 99%

“…The earliest Late Cretaceous eutherians, such as Bobolestes and Eozhelestes, also retain five lower premolars [44]; however, in two dentary specimens (described as 'Zhelestidae' indet., unnamed large sp. A [44, and references cited therein]) from the lower Cenomanian of Uzbekistan, the px has been lost and a long diastema is present between p2 and p3.…”

Section: Comparison and Discussionmentioning

confidence: 99%

“…The primitive lower incisor count for eutherians is possibly four [11,47]. Several early eutherians, such as Bobolestes, Eomaia, Eozhelestes and Juramaia have four lower incisors [3,4,44]; there are also some later forms, such as Asioryctes, Kulbeckia and Ukhaatherium, which have four lower incisors [30,48,49], although one of the earlier eutherian mammals, Acristatherium, has only three incisors [5]. Sasayamamylos kawaii shows a polymorphic intermediate state between primitive forms with four lower incisors and those with three; this indicates that the reduction in the incisor count in the lineage to which Sasayamalestes belongs started from i4.…”

Section: Comparison and Discussionmentioning

confidence: 99%

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A new Early Cretaceous eutherian mammal from the Sasayama Group, Hyogo, Japan

et al. 2013

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We here describe a new Early Cretaceous (early Albian) eutherian mammal, Sasayamamylos kawaii gen. et sp. nov., from the 'Lower Formation' of the Sasayama Group, Hyogo Prefecture, Japan. Sasayamamylos kawaii is characterized by a robust dentary, a distinct angle on the ventral margin of the dentary at the posterior end of the mandibular symphysis, a lower dental formula of 3 -4 : 1 : 4 : 3, a robust lower canine, a non-molariform lower ultimate premolar, and a secondarily reduced entoconid on the molars. To date, S. kawaii is the earliest known eutherian mammal possessing only four premolars, which demonstrates that the reduction in the premolar count in eutherians started in the late Early Cretaceous. The occurrence of S. kawaii implies that the relatively rapid diversification of eutherians in the mid-Cretaceous had already started by the early Albian.

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Section: Comparison and Discussionmentioning

confidence: 99%

Section: Comparison and Discussionmentioning

confidence: 99%

Section: Comparison and Discussionmentioning

confidence: 99%

Section: Comparison and Discussionmentioning

confidence: 99%

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A new Early Cretaceous eutherian mammal from the Sasayama Group, Hyogo, Japan

et al. 2013

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“…1). The localities of the Khodzhakul Formation include Chelpyk (SCH-1 and SCH-"B" sites), Khodzhakul I (SKH-20 site), Khodzhakulsai (SKH-4, SKH-5, and SKH-25 sites), and Sheikhdzheili (SSHD-8 and SSHD-8a sites) (see Averianov and Archibald [2005] for more details about the localities of the Khodzhakul Formation). In addition, one more locality known as Khodzhakul II (SKH-26 site) contains Cenomanian remains from the Khodzhakul Formation which were redeposited in Late Paleocene sands (Nessov, 1997).…”

Section: Introductionmentioning

confidence: 99%

Soft-shelled turtles (Trionychidae) from the Cenomanian of Uzbekistan

Vitek

Danilov

2014

Cretaceous Research

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a b s t r a c tLocalities from the Cenomanian of Uzbekistan are the oldest in Middle Asia and Kazakhstan to preserve two broadly sympatric species of trionychid turtle. Material described here comes from multiple Cenomanian formations from the Itemir locality, and from multiple localities in the Cenomanian Khodzhakul Formation. The first taxon from the locality, "Trionyx" cf. kyrgyzensis, has multiple morphological similarities with the older, Early Cretaceous "Trionyx" kyrgyzensis. In contrast, the second taxon, "Trionyx" dissolutus, has multiple similarities with "Trionyx" kansaiensis, one of two species of trionychid found in younger Late Cretaceous localities. "Trionyx" dissolutus bears some superficial resemblance to other trionychid taxa within the clade Plastomenidae because of its highly ossified plastron with a hyoplastral lappet and an epiplastral notch. However, Plastomenidae is diagnosed primarily through characters that are absent or cannot be observed in the available material of "T." dissolutus, and other shared features are plesiomorphic. In addition, "T." dissolutus shares other synapomorphies with Trionychinae. A heavily ossified plastron may be more homoplastric within Trionychidae than has been previously recognized. Finally, we provide an improved understanding of the subtle similarities and differences between several closely related Cretaceous turtle assemblages of Middle Asia and Kazakhstan.

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Evolutionary transition of dental formula in Late Cretaceous eutherian mammals

Averianov

Archibald

2015

Sci Nat

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Kulbeckia kulbecke, stem placental mammal from the Late Cretaceous of Uzbekistan, shows a transitional stage of evolution in the dental formula from five to four premolars. A non-replaced dP3/dp3 may occur as individual variation. In other specimens, the lower premolars are crowded with no space for development of dp3. As is evident from the CT scanning of one juvenile specimen, the development of dp3 started in a late ontogenetic stage and was confined to the pulp cavity of the developing p2. This dp3 would have been resorbed in a later ontogenetic stage, as the roots of p2 formed. The initial stage of reduction of the third premolar can be traced to stem therians (Juramaia and Eomaia), which have both dP3 and P3 present in the adult dentition. Further delay in the development of dP3/dp3 led to the loss of the permanent P3/p3 (a possible synapomorphy for Eutheria). The dP3/dp3 was present during most of the adult stages in the Late Cretaceous stem placentals Zhelestidae and Gypsonictops. This tooth is totally absent in basal taxa of Placentalia, which normally have at most four premolars.

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Mammals from the mid-Cretaceous Khodzhakul Formation, Kyzylkum Desert, Uzbekistan

Cited by 45 publications

References 24 publications

A new Early Cretaceous eutherian mammal from the Sasayama Group, Hyogo, Japan

A new Early Cretaceous eutherian mammal from the Sasayama Group, Hyogo, Japan

Soft-shelled turtles (Trionychidae) from the Cenomanian of Uzbekistan

Evolutionary transition of dental formula in Late Cretaceous eutherian mammals

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