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An Extremely Peramorphic Newt (Urodela: Salamandridae: Pleurodelini) from the Latest Oligocene of Germany, and a New Phylogenetic Analysis of Extant and Extinct Salamandrids.

Marjanović D, Witzmann F - PLoS ONE (2015)

Bottom Line: Referral to a species would require a revision of the genus, but the specimen likely does not belong to the type species.The Miocene "Triturus" roehrsi is found neither with the extant Ommatotriton nor with Lissotriton, but inside an Asian/aquatic clade or, when geographic distribution is included as a character, as the sister-group to all other European molgins.The main cause for discrepancies between the results and the molecular consensus is not heterochrony, but adaptations to a life in mountain streams; this is the most likely reason why the Paleocene Koalliella from western Europe forms the sister-group to some or all of the most aquatic extant newts in different analyses.

View Article: PubMed Central - PubMed

Affiliation: Museum für Naturkunde, Leibniz Institute for Evolutionary and Biodiversity Research, Humboldt University, Berlin, Germany.

ABSTRACT
We describe an Oligocene newt specimen from western Germany that has gone practically unnoticed in the literature despite having been housed in the Museum für Naturkunde (Berlin) for a century. It is referable to the coeval Chelotriton, but is unusually peramorphic; for many characters it is more peramorphic than all other caudates or even all other lissamphibians. Most noticeable are the position of the jaw joints far caudal to the occiput, the honeycombed sculpture on the maxilla, and the possible presence of a septomaxilla (which would be unique among salamandrids). Referral to a species would require a revision of the genus, but the specimen likely does not belong to the type species. A phylogenetic analysis of nonmolecular characters of Salamandridae, far larger than all predecessors, confirms the referral to Chelotriton. It further loosely associates the Oligocene Archaeotriton and the Miocene Carpathotriton with the extant Lissotriton, though the former may alternatively lie outside Pleurodelinae altogether. The Miocene? I. randeckensis may not belong to the extant Ichthyosaura. The Miocene "Triturus" roehrsi is found neither with the extant Ommatotriton nor with Lissotriton, but inside an Asian/aquatic clade or, when geographic distribution is included as a character, as the sister-group to all other European molgins. The main cause for discrepancies between the results and the molecular consensus is not heterochrony, but adaptations to a life in mountain streams; this is the most likely reason why the Paleocene Koalliella from western Europe forms the sister-group to some or all of the most aquatic extant newts in different analyses. We would like to urge neontologists working on salamandrids to pay renewed attention to the skeleton, not limited to the skull, as a source of diagnostic and phylogenetically informative characters.

No MeSH data available.


Reconstruction of the skull of MB.Am.45 in dorsal view.Sculpture omitted. We have not corrected for dorsoventral compression because the palate is unknown; note, however, that the skull was clearly rather flat in life, there have not been any anteroposterior shifts, and the dorsoventral compression appears to have slightly decreased the interorbital width. Abbreviations: al.pr, alary process of premaxilla;? eo-ot, probably exoccipital and opisthotic (see text); f, frontal; m, maxilla; n, nasal; ort, orbitotemporal fenestra; p, parietal; pm, premaxilla; po, postorbital opening (supratemporal fenestra); prf, prefrontal;? pt, probable pterygoid; qj-q, quadratojugal-quadrate bone; sq, squamosal; x, bone of unclear identity (see text).
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pone.0137068.g007: Reconstruction of the skull of MB.Am.45 in dorsal view.Sculpture omitted. We have not corrected for dorsoventral compression because the palate is unknown; note, however, that the skull was clearly rather flat in life, there have not been any anteroposterior shifts, and the dorsoventral compression appears to have slightly decreased the interorbital width. Abbreviations: al.pr, alary process of premaxilla;? eo-ot, probably exoccipital and opisthotic (see text); f, frontal; m, maxilla; n, nasal; ort, orbitotemporal fenestra; p, parietal; pm, premaxilla; po, postorbital opening (supratemporal fenestra); prf, prefrontal;? pt, probable pterygoid; qj-q, quadratojugal-quadrate bone; sq, squamosal; x, bone of unclear identity (see text).

Mentions: Photograph of MB.Am.45.3 showing honeycombed sculpture on the right maxilla and tubercles on most other bones (connected to form ridges on the right frontosquamosal arch) as well as the sutures between the parietals, frontals, nasals and prefrontals (compare Fig 7). Additionally, the left unidentified bone is visible, as are the vertical triangular processes of the premaxillae. Abbreviations: cb, ceratobranchials; ch, ceratohyal;? eo-ot, probably exoccipital and opisthotic (see text); m, maxilla; ort, orbitotemporal fenestra; pm, premaxilla; po, postorbital opening (supratemporal fenestra);? pt, probable pterygoid; qj-q, quadratojugal-quadrate bone; sq, squamosal; x, bone of unclear identity (see text). The nasals, prefrontal, frontals and parietals are not marked in order to avoid obscuring their sculpture; compare Fig 7.


An Extremely Peramorphic Newt (Urodela: Salamandridae: Pleurodelini) from the Latest Oligocene of Germany, and a New Phylogenetic Analysis of Extant and Extinct Salamandrids.

Marjanović D, Witzmann F - PLoS ONE (2015)

Reconstruction of the skull of MB.Am.45 in dorsal view.Sculpture omitted. We have not corrected for dorsoventral compression because the palate is unknown; note, however, that the skull was clearly rather flat in life, there have not been any anteroposterior shifts, and the dorsoventral compression appears to have slightly decreased the interorbital width. Abbreviations: al.pr, alary process of premaxilla;? eo-ot, probably exoccipital and opisthotic (see text); f, frontal; m, maxilla; n, nasal; ort, orbitotemporal fenestra; p, parietal; pm, premaxilla; po, postorbital opening (supratemporal fenestra); prf, prefrontal;? pt, probable pterygoid; qj-q, quadratojugal-quadrate bone; sq, squamosal; x, bone of unclear identity (see text).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4589347&req=5

pone.0137068.g007: Reconstruction of the skull of MB.Am.45 in dorsal view.Sculpture omitted. We have not corrected for dorsoventral compression because the palate is unknown; note, however, that the skull was clearly rather flat in life, there have not been any anteroposterior shifts, and the dorsoventral compression appears to have slightly decreased the interorbital width. Abbreviations: al.pr, alary process of premaxilla;? eo-ot, probably exoccipital and opisthotic (see text); f, frontal; m, maxilla; n, nasal; ort, orbitotemporal fenestra; p, parietal; pm, premaxilla; po, postorbital opening (supratemporal fenestra); prf, prefrontal;? pt, probable pterygoid; qj-q, quadratojugal-quadrate bone; sq, squamosal; x, bone of unclear identity (see text).
Mentions: Photograph of MB.Am.45.3 showing honeycombed sculpture on the right maxilla and tubercles on most other bones (connected to form ridges on the right frontosquamosal arch) as well as the sutures between the parietals, frontals, nasals and prefrontals (compare Fig 7). Additionally, the left unidentified bone is visible, as are the vertical triangular processes of the premaxillae. Abbreviations: cb, ceratobranchials; ch, ceratohyal;? eo-ot, probably exoccipital and opisthotic (see text); m, maxilla; ort, orbitotemporal fenestra; pm, premaxilla; po, postorbital opening (supratemporal fenestra);? pt, probable pterygoid; qj-q, quadratojugal-quadrate bone; sq, squamosal; x, bone of unclear identity (see text). The nasals, prefrontal, frontals and parietals are not marked in order to avoid obscuring their sculpture; compare Fig 7.

Bottom Line: Referral to a species would require a revision of the genus, but the specimen likely does not belong to the type species.The Miocene "Triturus" roehrsi is found neither with the extant Ommatotriton nor with Lissotriton, but inside an Asian/aquatic clade or, when geographic distribution is included as a character, as the sister-group to all other European molgins.The main cause for discrepancies between the results and the molecular consensus is not heterochrony, but adaptations to a life in mountain streams; this is the most likely reason why the Paleocene Koalliella from western Europe forms the sister-group to some or all of the most aquatic extant newts in different analyses.

View Article: PubMed Central - PubMed

Affiliation: Museum für Naturkunde, Leibniz Institute for Evolutionary and Biodiversity Research, Humboldt University, Berlin, Germany.

ABSTRACT
We describe an Oligocene newt specimen from western Germany that has gone practically unnoticed in the literature despite having been housed in the Museum für Naturkunde (Berlin) for a century. It is referable to the coeval Chelotriton, but is unusually peramorphic; for many characters it is more peramorphic than all other caudates or even all other lissamphibians. Most noticeable are the position of the jaw joints far caudal to the occiput, the honeycombed sculpture on the maxilla, and the possible presence of a septomaxilla (which would be unique among salamandrids). Referral to a species would require a revision of the genus, but the specimen likely does not belong to the type species. A phylogenetic analysis of nonmolecular characters of Salamandridae, far larger than all predecessors, confirms the referral to Chelotriton. It further loosely associates the Oligocene Archaeotriton and the Miocene Carpathotriton with the extant Lissotriton, though the former may alternatively lie outside Pleurodelinae altogether. The Miocene? I. randeckensis may not belong to the extant Ichthyosaura. The Miocene "Triturus" roehrsi is found neither with the extant Ommatotriton nor with Lissotriton, but inside an Asian/aquatic clade or, when geographic distribution is included as a character, as the sister-group to all other European molgins. The main cause for discrepancies between the results and the molecular consensus is not heterochrony, but adaptations to a life in mountain streams; this is the most likely reason why the Paleocene Koalliella from western Europe forms the sister-group to some or all of the most aquatic extant newts in different analyses. We would like to urge neontologists working on salamandrids to pay renewed attention to the skeleton, not limited to the skull, as a source of diagnostic and phylogenetically informative characters.

No MeSH data available.