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Biogeography and taxonomy of extinct and endangered monk seals illuminated by ancient DNA and skull morphology.

Scheel DM, Slater GJ, Kolokotronis SO, Potter CW, Rotstein DS, Tsangaras K, Greenwood AD, Helgen KM - Zookeys (2014)

Bottom Line: Molecular, morphological and temporal divergence between the Mediterranean and "New World monk seals" (Hawaiian and Caribbean) is profound, equivalent to or greater than between sister genera of phocids.As a result, we classify the Caribbean and Hawaiian monk seals together in a newly erected genus, Neomonachus.The two genera of extant monk seals (Monachus and Neomonachus) represent old evolutionary lineages each represented by a single critically endangered species, both warranting continuing and concerted conservation attention and investment if they are to avoid the fate of their Caribbean relative.

View Article: PubMed Central - HTML - PubMed

Affiliation: Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Str. 17, 10315 Berlin, Germany.

ABSTRACT
Extinctions and declines of large marine vertebrates have major ecological impacts and are of critical concern in marine environments. The Caribbean monk seal, Monachus tropicalis, last definitively reported in 1952, was one of the few marine mammal species to become extinct in historical times. Despite its importance for understanding the evolutionary biogeography of southern phocids, the relationships of M. tropicalis to the two living species of critically endangered monk seals have not been resolved. In this study we present the first molecular data for M. tropicalis, derived from museum skins. Phylogenetic analysis of cytochrome b sequences indicates that M. tropicalis was more closely related to the Hawaiian rather than the Mediterranean monk seal. Divergence time estimation implicates the formation of the Panamanian Isthmus in the speciation of Caribbean and Hawaiian monk seals. Molecular, morphological and temporal divergence between the Mediterranean and "New World monk seals" (Hawaiian and Caribbean) is profound, equivalent to or greater than between sister genera of phocids. As a result, we classify the Caribbean and Hawaiian monk seals together in a newly erected genus, Neomonachus. The two genera of extant monk seals (Monachus and Neomonachus) represent old evolutionary lineages each represented by a single critically endangered species, both warranting continuing and concerted conservation attention and investment if they are to avoid the fate of their Caribbean relative.

No MeSH data available.


Related in: MedlinePlus

Ventral views of palates of aMonachus monachusbNeomonachus schauinslandi, and cNeomonachus tropicalis. The tooth row of Monachus is more crowded, likely as a result of the shorter rostrum, and this results in a more obliquely oriented set of post-canine teeth and the lack of a diastema between the upper canine and the first premolar. In Neomonachus, there is a distinct diastema between C1 and P1, and the post-canine teeth are arranged more linearly. The upper incisor arcade of Monachus is slightly parabolic due to the posterior placement of the lateral incisors, and the anterior premaxilla appears slightly curved. In Neomonachus, the incisor arcade is linear and the anterior premaxilla is straight.
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Figure 6: Ventral views of palates of aMonachus monachusbNeomonachus schauinslandi, and cNeomonachus tropicalis. The tooth row of Monachus is more crowded, likely as a result of the shorter rostrum, and this results in a more obliquely oriented set of post-canine teeth and the lack of a diastema between the upper canine and the first premolar. In Neomonachus, there is a distinct diastema between C1 and P1, and the post-canine teeth are arranged more linearly. The upper incisor arcade of Monachus is slightly parabolic due to the posterior placement of the lateral incisors, and the anterior premaxilla appears slightly curved. In Neomonachus, the incisor arcade is linear and the anterior premaxilla is straight.

Mentions: Species of Neomonachus can be distinguished from Monachus in their smaller average body size and in lacking a white ventral patch on the pelage (in both adults and young) (Adam 2004). Species of Neomonachus possess a narrower and more gracile skull than Monachus, with relatively poorly developed sagittal and occipital crests in even the largest males (Figure 5). The rostrum is low and elongate with a conspicuous diastema between C1 and the first upper premolar (P1). In Monachus, the diastema is lacking and the anterior edge of P1 may be positioned medially to the canine (Figures 5, 6). The antorbital process of the maxilla (Figure 7) is present in Monachus but is extremely reduced or absent in Neomonachus (King 1956). The nasals are relatively narrow and posteriorly extended in Neomonachus compared to Monachus (Figure 7). The zygomatic arch is dorso-ventrally shallow and the jugal portion lacks a well-developed masseteric margin ventrally or orbital margin superiorly (the zygomatic arch is robust and both margins are well-defined in Monachus) (Figure 5). The pterygoid shows a conspicuous, laterally flared hamular process in Neomonachus (King 1956) that may be spatulate (Neomonachus schauinslandi) or hook-like (Neomonachus tropicalis); the process is absent or small and medially inflected in Monachus (Figure 8).


Biogeography and taxonomy of extinct and endangered monk seals illuminated by ancient DNA and skull morphology.

Scheel DM, Slater GJ, Kolokotronis SO, Potter CW, Rotstein DS, Tsangaras K, Greenwood AD, Helgen KM - Zookeys (2014)

Ventral views of palates of aMonachus monachusbNeomonachus schauinslandi, and cNeomonachus tropicalis. The tooth row of Monachus is more crowded, likely as a result of the shorter rostrum, and this results in a more obliquely oriented set of post-canine teeth and the lack of a diastema between the upper canine and the first premolar. In Neomonachus, there is a distinct diastema between C1 and P1, and the post-canine teeth are arranged more linearly. The upper incisor arcade of Monachus is slightly parabolic due to the posterior placement of the lateral incisors, and the anterior premaxilla appears slightly curved. In Neomonachus, the incisor arcade is linear and the anterior premaxilla is straight.
© Copyright Policy - creative-commons-attribution
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4042687&req=5

Figure 6: Ventral views of palates of aMonachus monachusbNeomonachus schauinslandi, and cNeomonachus tropicalis. The tooth row of Monachus is more crowded, likely as a result of the shorter rostrum, and this results in a more obliquely oriented set of post-canine teeth and the lack of a diastema between the upper canine and the first premolar. In Neomonachus, there is a distinct diastema between C1 and P1, and the post-canine teeth are arranged more linearly. The upper incisor arcade of Monachus is slightly parabolic due to the posterior placement of the lateral incisors, and the anterior premaxilla appears slightly curved. In Neomonachus, the incisor arcade is linear and the anterior premaxilla is straight.
Mentions: Species of Neomonachus can be distinguished from Monachus in their smaller average body size and in lacking a white ventral patch on the pelage (in both adults and young) (Adam 2004). Species of Neomonachus possess a narrower and more gracile skull than Monachus, with relatively poorly developed sagittal and occipital crests in even the largest males (Figure 5). The rostrum is low and elongate with a conspicuous diastema between C1 and the first upper premolar (P1). In Monachus, the diastema is lacking and the anterior edge of P1 may be positioned medially to the canine (Figures 5, 6). The antorbital process of the maxilla (Figure 7) is present in Monachus but is extremely reduced or absent in Neomonachus (King 1956). The nasals are relatively narrow and posteriorly extended in Neomonachus compared to Monachus (Figure 7). The zygomatic arch is dorso-ventrally shallow and the jugal portion lacks a well-developed masseteric margin ventrally or orbital margin superiorly (the zygomatic arch is robust and both margins are well-defined in Monachus) (Figure 5). The pterygoid shows a conspicuous, laterally flared hamular process in Neomonachus (King 1956) that may be spatulate (Neomonachus schauinslandi) or hook-like (Neomonachus tropicalis); the process is absent or small and medially inflected in Monachus (Figure 8).

Bottom Line: Molecular, morphological and temporal divergence between the Mediterranean and "New World monk seals" (Hawaiian and Caribbean) is profound, equivalent to or greater than between sister genera of phocids.As a result, we classify the Caribbean and Hawaiian monk seals together in a newly erected genus, Neomonachus.The two genera of extant monk seals (Monachus and Neomonachus) represent old evolutionary lineages each represented by a single critically endangered species, both warranting continuing and concerted conservation attention and investment if they are to avoid the fate of their Caribbean relative.

View Article: PubMed Central - HTML - PubMed

Affiliation: Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Str. 17, 10315 Berlin, Germany.

ABSTRACT
Extinctions and declines of large marine vertebrates have major ecological impacts and are of critical concern in marine environments. The Caribbean monk seal, Monachus tropicalis, last definitively reported in 1952, was one of the few marine mammal species to become extinct in historical times. Despite its importance for understanding the evolutionary biogeography of southern phocids, the relationships of M. tropicalis to the two living species of critically endangered monk seals have not been resolved. In this study we present the first molecular data for M. tropicalis, derived from museum skins. Phylogenetic analysis of cytochrome b sequences indicates that M. tropicalis was more closely related to the Hawaiian rather than the Mediterranean monk seal. Divergence time estimation implicates the formation of the Panamanian Isthmus in the speciation of Caribbean and Hawaiian monk seals. Molecular, morphological and temporal divergence between the Mediterranean and "New World monk seals" (Hawaiian and Caribbean) is profound, equivalent to or greater than between sister genera of phocids. As a result, we classify the Caribbean and Hawaiian monk seals together in a newly erected genus, Neomonachus. The two genera of extant monk seals (Monachus and Neomonachus) represent old evolutionary lineages each represented by a single critically endangered species, both warranting continuing and concerted conservation attention and investment if they are to avoid the fate of their Caribbean relative.

No MeSH data available.


Related in: MedlinePlus