Dental development and first premolar homology in placental mammals

McKay, Calum J.; Welbourn-Green, Claudia; Seiffert, Erik R.; Sallam, Hesham; Li, Jessica; Kakarala, Sophia E.; Bennett, Nigel C.; Asher, Robert J.

doi:10.3897/vz.72.e78234

Cited by 4 publications

(1 citation statement)

References 32 publications

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“…The sequence of tooth eruption of some leptictids and erinaceids shows that the molars erupted before the permanent premolars (Slaghter et al, 1974). The DP1 is the first to be erupted in Leptictis ( Ictops) bicuspis , Echinosorex gymnurus , and Hylomys suillus , and this may suggest that the permanent P1 may be the last one to be erupted, although documented DP1 replacements in mammals are rare enough to be cautious of such occurrences (Uhen, 2000; Asher et al, 2017; McKay et al, 2022). This situation occurs in IVPP V7349, in which the right P1–4 and left P2–4 are fully erupted; however, the left P1 is much smaller than the right, which is just erupting (fig.…”

Section: Systematic Paleontologymentioning

confidence: 99%

Cranial and Postcranial Morphology of the Insectivoran-Grade Mammals Hsiangolestes and Naranius (Mammalia, Eutheria) with Analyses of Their Phylogenetic Relationships

Ting

Wang

Meng

2023

Bulletin of the American Museum of Natural History

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Early Cenozoic “insectivorans” possess some of the most primitive morphologies among eutherian mammals. Studies of these archaic mammals offer insights into the early diversifications of basal eutherians. Despite such importance, early fossil “insectivorans” from Asia are poorly known due to a scarcity of fossil remains, which often consist only of fragmentary jaws and teeth. Discoveries of remarkably well-preserved fossil “insectivorans”, including complete skulls and articulated postcranial skeletons, from the early Eocene Hengyang Basin in south-central Hunan Province, China, offer a rare opportunity to thoroughly study two taxa belonging to different families.Fine-grained red beds from Hengyang Basin preserve extraordinary fossils with morphological structures rarely seen elsewhere. Thin sections of a skull of Hsiangolestes youngi Zheng and Huang, 1984, for example, reveal the extremely delicate nasal and maxillary turbinates, which, as far as we are aware, are the first known from fossils of this age. We thus take this opportunity to document in detail the cranial and dental morphology, as well as postcranial skeletons, of the Hengyang “insectivorans.”.In this monograph, we describe several complete skulls and serial sections of a skull, as well as many partial skulls, mandibles, and postcranial skeletons of Hsiangolestes youngi, an Asian early Eocene insectivoran-grade mammal. We also report a new species of Naranius Russell and Dashzeveg, 1986—N. hengdongensis—an Asian early Eocene cimolestid and describe its well-preserved skulls and mandibles.Hsiangolestes is endemic to Asia. It is currently known only from the earliest Eocene Lingcha Formation, Hengyang Basin, Hunan Province, China. Naranius closely resembles Cimolestes Marsh, 1889, the type genus of the family Cimolestidae. It is mainly distributed in Asia and known from the earliest Eocene deposits in the Bumban Member of the Naran Bulak Formation, Nemegt Basin, of Mongolia, and the Lingcha Formation, Hengyang Basin, Hunan Province, China. The only record of Naranius reported outside of Asia is N. americanus from the early Wasatchian Red Hot Local Fauna, Mississippi, United States.Using PAUP and TNT search algorithms, we place these Hengyang taxa within phylogenetic context of other fossil “insectivorans” from the Mesozoic and early Cenozoic of Asia together with some well-known Holarctic taxa. A phylogenetic analysis of 290 cranial and dental characters from 36 fossil and modern insectivoran-grade taxa is presented, focusing on new materials of Hsiangolestes youngi and Naranius hengdongensis. Based on the results of our phylogenetic analyses, we propose that (1) Hsiangolestes, Prosarcodon, Sarcodon, and Sinosinopa, form a monophyletic group, for which we propose the family name Sarcodontidae; (2) the family Cimolestidae should be restricted to Naranius and Cimolestes, which are sister taxa; (3) the systematic position of Naranius americanus is uncertain; and (4) the family Micropternodontidae should be restricted to Micropternodus and its alli...

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Section: Systematic Paleontologymentioning

confidence: 99%

Cranial and Postcranial Morphology of the Insectivoran-Grade Mammals Hsiangolestes and Naranius (Mammalia, Eutheria) with Analyses of Their Phylogenetic Relationships

Ting

Wang

Meng

2023

Bulletin of the American Museum of Natural History

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Dental eruption and adult dentition of the enigmatic ptolemaiid Qarunavus meyeri from the Oligocene of the Fayum Depression (Egypt) revealed by micro-computed tomography clarifies its phylogenetic position

Kampouridis,

Hartung,

Augustin

et al. 2023

Zoological Journal of the Linnean Society

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The Palaeogene is a very important time period for mammalian evolution because it documents the first occurrence of many groups. One such group is the enigmatic Ptolemaiida, best known from the Early Oligocene of the Fayum Depression in Egypt, where it is represented by three genera, Ptolemaia, Qarunavus, and Cleopatrodon, including five species. Among these, Qarunavus meyeri is especially rare, as it is only known from two partial juvenile mandibles. Herein, the affinities of this taxon are re-investigated by applying micro-computed tomography (μCT), thus enabling the study and comparison of its unerupted permanent dentition with that of other ptolemaiidans. The μCT analysis confirms that Q. meyeri is a valid species, distinct from all other ptolemaiidans. Both the comparison and a phylogenetic analysis suggest a closer relationship of Qarunavus to the genus Cleopatrodon than to Ptolemaia; thereby, placing Qarunavus in the family Ptolemaiidae. Furthermore, the μCT analysis enabled the assessment of the dental morphology of Q. meyeri revealing an unusual combination of traits, such as a very small single incisor next to a large canine. The eruption sequence of the permanent dentition in Q. meyeri implies a late dental eruption for the species, which would support the hypothesis of Ptolemaiida belonging to Afrotheria.

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Cranial Anatomy and Petrosal Morphology of a Juvenile Individual of Neobrachytherium (Proterotheriidae, Litopterna, Mammalia)

Armella,

García-López,

Croft

2024

American Museum Novitates

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Dental development and first premolar homology in placental mammals

Cited by 4 publications

References 32 publications

Cranial and Postcranial Morphology of the Insectivoran-Grade Mammals Hsiangolestes and Naranius (Mammalia, Eutheria) with Analyses of Their Phylogenetic Relationships

Cranial and Postcranial Morphology of the Insectivoran-Grade Mammals Hsiangolestes and Naranius (Mammalia, Eutheria) with Analyses of Their Phylogenetic Relationships

Dental eruption and adult dentition of the enigmatic ptolemaiid Qarunavus meyeri from the Oligocene of the Fayum Depression (Egypt) revealed by micro-computed tomography clarifies its phylogenetic position

Cranial Anatomy and Petrosal Morphology of a Juvenile Individual of Neobrachytherium (Proterotheriidae, Litopterna, Mammalia)

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