Limits...
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.


Photograph of the silicone cast MB.Am.45.3.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4589347&req=5

pone.0137068.g005: Photograph of the silicone cast MB.Am.45.3.

Mentions: MB.Am.45 consists of the original fossil (MB.Am.45.1) and two casts (MB.Am.45.2–3). MB.Am.45.1 (Fig 4) is a natural mold of the dorsal side of a skull, anterior trunk and right forelimb in articulation apart from broken neural spines, ribs angled out of position, and some crushing and cracking. No original bone is preserved, and there is no counterpart. MB.Am.45.2 is an old plaster cast showing few details of the skeleton; the entire surface is spongy and abraded to the point of being smooth (S2 and S3 Figs). Therefore, a silicone cast (MB.Am.45.3; Figs 5 and 8–14) was made by the preparator Markus Brinkmann (Museum für Naturkunde); the following description is based on that cast, as are the specimen drawing (Fig 6) and the skull reconstruction (Fig 7). Specimen MB.Am.45.1 was found in the lignite (Blätterkohle, “leaf coal”) of Orsberg near Erpel, close to Linz in Rhineland-Palatinate, Germany. Apart from Orsberg, the Blätterkohle crops out in several localities in the Siebengebirge region near Bonn, like Erpel, Stößchen near Linz, and the famous Rott near Hennef. Based on mammal stratigraphy, the Blätterkohle is latest Oligocene in age; it was formed under lacustrine conditions [14,37].


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)

Photograph of the silicone cast MB.Am.45.3.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0137068.g005: Photograph of the silicone cast MB.Am.45.3.
Mentions: MB.Am.45 consists of the original fossil (MB.Am.45.1) and two casts (MB.Am.45.2–3). MB.Am.45.1 (Fig 4) is a natural mold of the dorsal side of a skull, anterior trunk and right forelimb in articulation apart from broken neural spines, ribs angled out of position, and some crushing and cracking. No original bone is preserved, and there is no counterpart. MB.Am.45.2 is an old plaster cast showing few details of the skeleton; the entire surface is spongy and abraded to the point of being smooth (S2 and S3 Figs). Therefore, a silicone cast (MB.Am.45.3; Figs 5 and 8–14) was made by the preparator Markus Brinkmann (Museum für Naturkunde); the following description is based on that cast, as are the specimen drawing (Fig 6) and the skull reconstruction (Fig 7). Specimen MB.Am.45.1 was found in the lignite (Blätterkohle, “leaf coal”) of Orsberg near Erpel, close to Linz in Rhineland-Palatinate, Germany. Apart from Orsberg, the Blätterkohle crops out in several localities in the Siebengebirge region near Bonn, like Erpel, Stößchen near Linz, and the famous Rott near Hennef. Based on mammal stratigraphy, the Blätterkohle is latest Oligocene in age; it was formed under lacustrine conditions [14,37].

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.