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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.


Snout of MB.Am.45 at low angles in anterodorsal view, showing bone of unclear identity (see text).Photographs of MB.Am.45.3, showing premaxillae, right maxilla, right unidentified bone, right nasal and right prefrontal in focus; the sculpture and various sutures are visible. (A) in anterodorsal view; (B) was taken in anterodorsolateral view by holding a camera to an ocular of a binocular microscope and is a close-up on the right nostril (the bottom of which is out of focus) and its surroundings, in particular the right unidentified bone. Abbreviations: l., left; r., right; f, frontal; m, maxilla; n, nasal; ort, orbitotemporal fenestra; pm, premaxilla; prf, prefrontal; x, bone of unclear identity.
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pone.0137068.g010: Snout of MB.Am.45 at low angles in anterodorsal view, showing bone of unclear identity (see text).Photographs of MB.Am.45.3, showing premaxillae, right maxilla, right unidentified bone, right nasal and right prefrontal in focus; the sculpture and various sutures are visible. (A) in anterodorsal view; (B) was taken in anterodorsolateral view by holding a camera to an ocular of a binocular microscope and is a close-up on the right nostril (the bottom of which is out of focus) and its surroundings, in particular the right unidentified bone. Abbreviations: l., left; r., right; f, frontal; m, maxilla; n, nasal; ort, orbitotemporal fenestra; pm, premaxilla; prf, prefrontal; x, bone of unclear identity.

Mentions: Premaxilla. Of the premaxillae, only the anteroposteriorly very short anterodorsal portion is exposed (Figs 9 and 10). Short, rather blunt, triangular alary processes (preserved vertical) are developed that overlap the anteriormost part of the nasals. The alary processes are widely separated from each other and from the median suture between the nasals, even at their bases (Fig 7). They are located medial to the external nares, but do not form their medial margins. As can be judged from the surface of the alary processes, the dermal sculpture of the premaxillae appears to be composed of pits and ridges. Because of incomplete preservation, it cannot be ascertained if the premaxillae were fused ventrally or not, although their anterior surfaces are clearly sutured. Teeth are exposed neither on the premaxilla nor on the maxilla.


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)

Snout of MB.Am.45 at low angles in anterodorsal view, showing bone of unclear identity (see text).Photographs of MB.Am.45.3, showing premaxillae, right maxilla, right unidentified bone, right nasal and right prefrontal in focus; the sculpture and various sutures are visible. (A) in anterodorsal view; (B) was taken in anterodorsolateral view by holding a camera to an ocular of a binocular microscope and is a close-up on the right nostril (the bottom of which is out of focus) and its surroundings, in particular the right unidentified bone. Abbreviations: l., left; r., right; f, frontal; m, maxilla; n, nasal; ort, orbitotemporal fenestra; pm, premaxilla; prf, prefrontal; x, bone of unclear identity.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0137068.g010: Snout of MB.Am.45 at low angles in anterodorsal view, showing bone of unclear identity (see text).Photographs of MB.Am.45.3, showing premaxillae, right maxilla, right unidentified bone, right nasal and right prefrontal in focus; the sculpture and various sutures are visible. (A) in anterodorsal view; (B) was taken in anterodorsolateral view by holding a camera to an ocular of a binocular microscope and is a close-up on the right nostril (the bottom of which is out of focus) and its surroundings, in particular the right unidentified bone. Abbreviations: l., left; r., right; f, frontal; m, maxilla; n, nasal; ort, orbitotemporal fenestra; pm, premaxilla; prf, prefrontal; x, bone of unclear identity.
Mentions: Premaxilla. Of the premaxillae, only the anteroposteriorly very short anterodorsal portion is exposed (Figs 9 and 10). Short, rather blunt, triangular alary processes (preserved vertical) are developed that overlap the anteriormost part of the nasals. The alary processes are widely separated from each other and from the median suture between the nasals, even at their bases (Fig 7). They are located medial to the external nares, but do not form their medial margins. As can be judged from the surface of the alary processes, the dermal sculpture of the premaxillae appears to be composed of pits and ridges. Because of incomplete preservation, it cannot be ascertained if the premaxillae were fused ventrally or not, although their anterior surfaces are clearly sutured. Teeth are exposed neither on the premaxilla nor on the maxilla.

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.