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First Miocene rodent from Lebanon provides the 'missing link' between Asian and African gundis (Rodentia: Ctenodactylidae).

López-Antoñanzas R, Knoll F, Maksoud S, Azar D - Sci Rep (2015)

Bottom Line: Proafricanomys libanensis nov. gen. nov. sp. shares a variety of dental characters with both the most primitive and derived members of the subfamily.A cladistic analysis demonstrates that this species is the sister taxon to a clade encompassing all but one of the African ctenodactylines, plus a southern European species of obvious African extraction.As such, Proafricanomys provides the 'missing link' between the Asian and African gundis.

View Article: PubMed Central - PubMed

Affiliation: 1] School of Earth Sciences, University of Bristol, Bristol, United Kingdom [2] Departamento de Paleobiología, Museo Nacional de Ciencias Naturales-CSIC, Madrid, Spain.

ABSTRACT
Ctenodactylinae (gundis) is a clade of rodents that experienced, in Miocene time, their greatest diversification and widest distribution. They expanded from the Far East, their area of origin, to Africa, which they entered from what would become the Arabian Peninsula. Questions concerning the origin of African Ctenodactylinae persist essentially because of a poor fossil record from the Miocene of Afro-Arabia. However, recent excavations in the Late Miocene of Lebanon have yielded a key taxon for our understanding of these issues. Proafricanomys libanensis nov. gen. nov. sp. shares a variety of dental characters with both the most primitive and derived members of the subfamily. A cladistic analysis demonstrates that this species is the sister taxon to a clade encompassing all but one of the African ctenodactylines, plus a southern European species of obvious African extraction. As such, Proafricanomys provides the 'missing link' between the Asian and African gundis.

No MeSH data available.


Evolutionary trends in the pattern of the cheek teeth in Ctenodactylinae.(A–D) evolution of the dp4. (A) dp4 of Sayimys assarrarensis with the plesiomorphies of having an anteroconid and both metalophulid II and metalophulid I; (B) dp4 of Metasayimys sivalensis with the plesiomorphy of having an anteroconid and the synapomorphy of having metalophulid I but not metalophulid II; (C) dp4 of Proafricanomys libanensis nov. gen. nov. sp. with the plesiomorphy of having an anteroconid and the synapomorphy of having metalophulid II but not metalophulid I; (D) dp4 of Africanomys pulcher with the synapomorphies of lacking an anteroconid and metalophulid I. (E–F) lower molars. (E) m3 of Proafricanomys libanensis with the plesiomorphy of having a well-developed posterolabial ledge. (F) m3 of Africanomys pulcher with the synapomorphy of lacking the posterolabial ledge. (G–H) DP4. (G) DP4 of Sayimys assarrarensis with the plesiomorphies of having a well-developed paraflexus and metaflexus; (H) DP4 of Africanomys pulcher with the synapomorphies of having small paraflexus and metaflexus. Images obtained from Scanning Electron Microscopy (SEM).
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f6: Evolutionary trends in the pattern of the cheek teeth in Ctenodactylinae.(A–D) evolution of the dp4. (A) dp4 of Sayimys assarrarensis with the plesiomorphies of having an anteroconid and both metalophulid II and metalophulid I; (B) dp4 of Metasayimys sivalensis with the plesiomorphy of having an anteroconid and the synapomorphy of having metalophulid I but not metalophulid II; (C) dp4 of Proafricanomys libanensis nov. gen. nov. sp. with the plesiomorphy of having an anteroconid and the synapomorphy of having metalophulid II but not metalophulid I; (D) dp4 of Africanomys pulcher with the synapomorphies of lacking an anteroconid and metalophulid I. (E–F) lower molars. (E) m3 of Proafricanomys libanensis with the plesiomorphy of having a well-developed posterolabial ledge. (F) m3 of Africanomys pulcher with the synapomorphy of lacking the posterolabial ledge. (G–H) DP4. (G) DP4 of Sayimys assarrarensis with the plesiomorphies of having a well-developed paraflexus and metaflexus; (H) DP4 of Africanomys pulcher with the synapomorphies of having small paraflexus and metaflexus. Images obtained from Scanning Electron Microscopy (SEM).

Mentions: The evolution of the dp4 in the Ctenodactylinae is characterized by the loss of the anteroconid and the metalophulid I, the connection of the metaconid to the metalophulid II, the shift anteriorly of the metaconid and the protoconid, and the subsequent lengthening of the posterior arm of the protoconid (Fig. 6A–D). The metalophulid I is lost prior to the disappearance of the anteroconid. The presence of the metalophulid I (6(0 → 1)) is a basal synapomorphy of Ctenodactylinae that is reversed (6 (1 → 0)) in the common ancestor of Proafricanomys and the more derived members of the group (Fig. 6A–D). The presence of the anteroconid on the dp4 (7(0 → 1)) is a basal synapomorphy that is lost at the level of Africanomys. Africanomys and the more derived Ctenodactylinae share the synapomorphy of having this structure reversed (7(1 → 0)) (Fig. 6D). The loss of the anteroconid on the dp4 is a consequence of the shift of the metaconid anteriorly (8(1 → 2)). Thus, Proafricanomys, which has already lost the metalophulid I, still maintain the anteroconid because even though the protoconid has already moved anteriorly, the metaconid is still lingually situated (8(1)), near the entoconid (Fig. 6C). The metaconid is connected to the metalophulid I (9(0 → 1)) in the most primitive ctenodactylines (Fig. 6A–B). Proafricanomys and the more derived ctenodactylines share the synapomorphy of having the metaconid joined to the metalophulid II (9(1 → 0)) (Fig. 6C–D). Thus, the most derived Ctenodactylinae show to some extent a return to deciduous premolar morphology that is typical for primitive ctenodactylids.


First Miocene rodent from Lebanon provides the 'missing link' between Asian and African gundis (Rodentia: Ctenodactylidae).

López-Antoñanzas R, Knoll F, Maksoud S, Azar D - Sci Rep (2015)

Evolutionary trends in the pattern of the cheek teeth in Ctenodactylinae.(A–D) evolution of the dp4. (A) dp4 of Sayimys assarrarensis with the plesiomorphies of having an anteroconid and both metalophulid II and metalophulid I; (B) dp4 of Metasayimys sivalensis with the plesiomorphy of having an anteroconid and the synapomorphy of having metalophulid I but not metalophulid II; (C) dp4 of Proafricanomys libanensis nov. gen. nov. sp. with the plesiomorphy of having an anteroconid and the synapomorphy of having metalophulid II but not metalophulid I; (D) dp4 of Africanomys pulcher with the synapomorphies of lacking an anteroconid and metalophulid I. (E–F) lower molars. (E) m3 of Proafricanomys libanensis with the plesiomorphy of having a well-developed posterolabial ledge. (F) m3 of Africanomys pulcher with the synapomorphy of lacking the posterolabial ledge. (G–H) DP4. (G) DP4 of Sayimys assarrarensis with the plesiomorphies of having a well-developed paraflexus and metaflexus; (H) DP4 of Africanomys pulcher with the synapomorphies of having small paraflexus and metaflexus. Images obtained from Scanning Electron Microscopy (SEM).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4528195&req=5

f6: Evolutionary trends in the pattern of the cheek teeth in Ctenodactylinae.(A–D) evolution of the dp4. (A) dp4 of Sayimys assarrarensis with the plesiomorphies of having an anteroconid and both metalophulid II and metalophulid I; (B) dp4 of Metasayimys sivalensis with the plesiomorphy of having an anteroconid and the synapomorphy of having metalophulid I but not metalophulid II; (C) dp4 of Proafricanomys libanensis nov. gen. nov. sp. with the plesiomorphy of having an anteroconid and the synapomorphy of having metalophulid II but not metalophulid I; (D) dp4 of Africanomys pulcher with the synapomorphies of lacking an anteroconid and metalophulid I. (E–F) lower molars. (E) m3 of Proafricanomys libanensis with the plesiomorphy of having a well-developed posterolabial ledge. (F) m3 of Africanomys pulcher with the synapomorphy of lacking the posterolabial ledge. (G–H) DP4. (G) DP4 of Sayimys assarrarensis with the plesiomorphies of having a well-developed paraflexus and metaflexus; (H) DP4 of Africanomys pulcher with the synapomorphies of having small paraflexus and metaflexus. Images obtained from Scanning Electron Microscopy (SEM).
Mentions: The evolution of the dp4 in the Ctenodactylinae is characterized by the loss of the anteroconid and the metalophulid I, the connection of the metaconid to the metalophulid II, the shift anteriorly of the metaconid and the protoconid, and the subsequent lengthening of the posterior arm of the protoconid (Fig. 6A–D). The metalophulid I is lost prior to the disappearance of the anteroconid. The presence of the metalophulid I (6(0 → 1)) is a basal synapomorphy of Ctenodactylinae that is reversed (6 (1 → 0)) in the common ancestor of Proafricanomys and the more derived members of the group (Fig. 6A–D). The presence of the anteroconid on the dp4 (7(0 → 1)) is a basal synapomorphy that is lost at the level of Africanomys. Africanomys and the more derived Ctenodactylinae share the synapomorphy of having this structure reversed (7(1 → 0)) (Fig. 6D). The loss of the anteroconid on the dp4 is a consequence of the shift of the metaconid anteriorly (8(1 → 2)). Thus, Proafricanomys, which has already lost the metalophulid I, still maintain the anteroconid because even though the protoconid has already moved anteriorly, the metaconid is still lingually situated (8(1)), near the entoconid (Fig. 6C). The metaconid is connected to the metalophulid I (9(0 → 1)) in the most primitive ctenodactylines (Fig. 6A–B). Proafricanomys and the more derived ctenodactylines share the synapomorphy of having the metaconid joined to the metalophulid II (9(1 → 0)) (Fig. 6C–D). Thus, the most derived Ctenodactylinae show to some extent a return to deciduous premolar morphology that is typical for primitive ctenodactylids.

Bottom Line: Proafricanomys libanensis nov. gen. nov. sp. shares a variety of dental characters with both the most primitive and derived members of the subfamily.A cladistic analysis demonstrates that this species is the sister taxon to a clade encompassing all but one of the African ctenodactylines, plus a southern European species of obvious African extraction.As such, Proafricanomys provides the 'missing link' between the Asian and African gundis.

View Article: PubMed Central - PubMed

Affiliation: 1] School of Earth Sciences, University of Bristol, Bristol, United Kingdom [2] Departamento de Paleobiología, Museo Nacional de Ciencias Naturales-CSIC, Madrid, Spain.

ABSTRACT
Ctenodactylinae (gundis) is a clade of rodents that experienced, in Miocene time, their greatest diversification and widest distribution. They expanded from the Far East, their area of origin, to Africa, which they entered from what would become the Arabian Peninsula. Questions concerning the origin of African Ctenodactylinae persist essentially because of a poor fossil record from the Miocene of Afro-Arabia. However, recent excavations in the Late Miocene of Lebanon have yielded a key taxon for our understanding of these issues. Proafricanomys libanensis nov. gen. nov. sp. shares a variety of dental characters with both the most primitive and derived members of the subfamily. A cladistic analysis demonstrates that this species is the sister taxon to a clade encompassing all but one of the African ctenodactylines, plus a southern European species of obvious African extraction. As such, Proafricanomys provides the 'missing link' between the Asian and African gundis.

No MeSH data available.