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A new Cretaceous Metatherian mammal from Henan, China.

Bi S, Jin X, Li S, Du T - PeerJ (2015)

Bottom Line: The new taxon, Lotheridium mengi, is based on a nearly complete skull and associated lower jaws with full adult dentition.Previous views on deltatheroidan relationships were diverse, but recent studies favored their metatherian affinity.The new species also indicates that deltatheroidan mammals were more diverse and had broader geographical distributions than previously thought.

View Article: PubMed Central - HTML - PubMed

Affiliation: Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences , Beijing , China ; Department of Biology, Indiana University of Pennsylvania , Indiana, PA , United States of America.

ABSTRACT
We report a new deltatheroidan mammal from the Upper Cretaceous of Henna, China. The new taxon, Lotheridium mengi, is based on a nearly complete skull and associated lower jaws with full adult dentition. Deltatheroidans are known mostly from fragmentary specimens from Asia and North America. Previous views on deltatheroidan relationships were diverse, but recent studies favored their metatherian affinity. The new specimen represents the most complete skull known for deltatheroidans and provides additional evidence that deltatheroidans already had the distinctive metatherian dental formula and replacement pattern and several other derived metatherian features, supporting the metatherian status for this clade. The new species also indicates that deltatheroidan mammals were more diverse and had broader geographical distributions than previously thought.

No MeSH data available.


The right mandible of Lotheridium mengi (ZMNH M9032).(A) Lateral view. (B) Close-up view of the lingual side of p2-m4. (C) Lingual view. (D) Occlusal view. (E) Close-up view of the occlusal surface of m1-m4. Scale bar for B and E, 5 mm; Scale bar for A, C and D, 10 mm.
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fig-3: The right mandible of Lotheridium mengi (ZMNH M9032).(A) Lateral view. (B) Close-up view of the lingual side of p2-m4. (C) Lingual view. (D) Occlusal view. (E) Close-up view of the occlusal surface of m1-m4. Scale bar for B and E, 5 mm; Scale bar for A, C and D, 10 mm.

Mentions: The mandible is robust with a gently curved ventral outline and has its maximum depth below m3 (Figs. 3A and 3C). In the lateral view, the mandible preserves two mental foramina, one below the p2 and the other below m1 (Fig. 1D). The coronoid process is tall, its anterior edge forming a 135° angle with the tooth row. The masseteric fossa is deeply excavated with strong superior and inferior crests. It terminates anteriorly below the base of the coronoid process, well distal to the last molar (Fig. 3A). On the lingual side, the symphysis is shallow and not fused. The pterygoid fossa is shallow and extends anteriorly to the posterior root of m2. The angular process is medially inflected as seen in Deltatheridium and living marsupials (Fig. 3C). At the anterodorsal base of the angular process a mandibular foramen can be seen. The elongate and transversely oriented condyle is low, near the level of the tooth row (Fig. 3C).


A new Cretaceous Metatherian mammal from Henan, China.

Bi S, Jin X, Li S, Du T - PeerJ (2015)

The right mandible of Lotheridium mengi (ZMNH M9032).(A) Lateral view. (B) Close-up view of the lingual side of p2-m4. (C) Lingual view. (D) Occlusal view. (E) Close-up view of the occlusal surface of m1-m4. Scale bar for B and E, 5 mm; Scale bar for A, C and D, 10 mm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4400878&req=5

fig-3: The right mandible of Lotheridium mengi (ZMNH M9032).(A) Lateral view. (B) Close-up view of the lingual side of p2-m4. (C) Lingual view. (D) Occlusal view. (E) Close-up view of the occlusal surface of m1-m4. Scale bar for B and E, 5 mm; Scale bar for A, C and D, 10 mm.
Mentions: The mandible is robust with a gently curved ventral outline and has its maximum depth below m3 (Figs. 3A and 3C). In the lateral view, the mandible preserves two mental foramina, one below the p2 and the other below m1 (Fig. 1D). The coronoid process is tall, its anterior edge forming a 135° angle with the tooth row. The masseteric fossa is deeply excavated with strong superior and inferior crests. It terminates anteriorly below the base of the coronoid process, well distal to the last molar (Fig. 3A). On the lingual side, the symphysis is shallow and not fused. The pterygoid fossa is shallow and extends anteriorly to the posterior root of m2. The angular process is medially inflected as seen in Deltatheridium and living marsupials (Fig. 3C). At the anterodorsal base of the angular process a mandibular foramen can be seen. The elongate and transversely oriented condyle is low, near the level of the tooth row (Fig. 3C).

Bottom Line: The new taxon, Lotheridium mengi, is based on a nearly complete skull and associated lower jaws with full adult dentition.Previous views on deltatheroidan relationships were diverse, but recent studies favored their metatherian affinity.The new species also indicates that deltatheroidan mammals were more diverse and had broader geographical distributions than previously thought.

View Article: PubMed Central - HTML - PubMed

Affiliation: Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences , Beijing , China ; Department of Biology, Indiana University of Pennsylvania , Indiana, PA , United States of America.

ABSTRACT
We report a new deltatheroidan mammal from the Upper Cretaceous of Henna, China. The new taxon, Lotheridium mengi, is based on a nearly complete skull and associated lower jaws with full adult dentition. Deltatheroidans are known mostly from fragmentary specimens from Asia and North America. Previous views on deltatheroidan relationships were diverse, but recent studies favored their metatherian affinity. The new specimen represents the most complete skull known for deltatheroidans and provides additional evidence that deltatheroidans already had the distinctive metatherian dental formula and replacement pattern and several other derived metatherian features, supporting the metatherian status for this clade. The new species also indicates that deltatheroidan mammals were more diverse and had broader geographical distributions than previously thought.

No MeSH data available.