Samstag, 9. Februar 2013
Madygen bryophytes and lycopsids
Moisan, P., S. Voigt, J. W. Schneider & H. Kerp. 2012. New fossil bryophytes from the Triassic Madygen Lagerstätte (SW Kyrgyzstan). Review of Palaeobotany and Palynology 187:29–37. [Abstract]
Recent paper on liverworts and leafy mosses from the Madygen Formation. Adds some new aspects about the Madygen flora which is known for its diversity of seed ferns, lycopsids, horsetails, and cycadophytes whereas (unambiguous) fossils of non-vascular plants, some of them occurring densely packed in shallow lacustrine sediments (and possibly represent submerged plants of the lake margin), have been described for the first time by Moisan and colleagues.
Moisan, P. & S. Voigt. 2013, in press. Lycopsids from the Madygen Lagerstätte (Middle to Late Triassic, Kyrgyzstan, Central Asia). Review of Palaeobotany and Palynology. [Abstract]
Revision of the Madygen lycopsids and of the problematic "Longisquama-appendage-like" foliage Mesenteriophyllum based on materials excavated between 2006 and 2009 whose macromorphological and microscopic epidermal features were studied. Originally described by Sixtel (1961) as a new genus of gymnosperms, Mesenteriophyllum-like plants are now found to belong to different higher lycopsid taxa (Pleuromeiales, Isoetales).
Montag, 9. Juli 2012
Insect-plant interaction in the Madygen forest
Philippe Moisan, who defended his Ph.D. thesis on floral remains from the Madygen Formation earlier this year, is main author of a recently published paper on ovipostion damage:
Moisan, P., C. C. Labandeira, N. A. Matushkina, T. Wappler, S. Voigt, and H. Kerp (2012): Lycopsid–arthropod associations and odonatopteran oviposition on Triassic herbaceous Isoetites. Palaeogeography, Palaeoclimatology, Palaeoecology 344–345: 6–15. [Link to abstract]
Describes an oviposition damage pattern typical for dragonflies on the quillwort Isoetites which is an unusual thing because lycopsids were not yet known to be hosts of dragonfly egg-laying.
Moisan, P., C. C. Labandeira, N. A. Matushkina, T. Wappler, S. Voigt, and H. Kerp (2012): Lycopsid–arthropod associations and odonatopteran oviposition on Triassic herbaceous Isoetites. Palaeogeography, Palaeoclimatology, Palaeoecology 344–345: 6–15. [Link to abstract]
Describes an oviposition damage pattern typical for dragonflies on the quillwort Isoetites which is an unusual thing because lycopsids were not yet known to be hosts of dragonfly egg-laying.
Dienstag, 27. März 2012
The Longisquama paper in press got some media coverage
Science writer Jeff Hecht wrote an article discussing results of our study:
Jeff Hecht: Reptile grew feather-like structures before dinosaurs. New Scientist, issue 2857, 23 March 2012.
Was a bit afraid of this, because often a finely nuanced statement is cited incorrectly or even turned into the opposite when the message of a paper is adapted for a non-specialist audience. Looks okay, though.
Jeff Hecht: Reptile grew feather-like structures before dinosaurs. New Scientist, issue 2857, 23 March 2012.
Was a bit afraid of this, because often a finely nuanced statement is cited incorrectly or even turned into the opposite when the message of a paper is adapted for a non-specialist audience. Looks okay, though.
Sonntag, 4. März 2012
New papers on Kyrgyzsaurus, Madygenerpeton, and Longisquama
Alifanov, V. R. and E. N. Kurochkin. 2011..Kyrgyzsaurus bukhanchenkoi gen. et sp. nov., a new reptile from the Triassic of southwestern Kyrgyzstan. Paleontological Journal 45(6):639-647.
[DOI: 10.1134/S0031030111060025] [link]
Description of a reptile fossil with skin preservation discovered in 2006. Comes form the same locality as Sharovipteryx and Longisquama. The authors interpret the specimen as a member of drepanosaurs, a Late Triassic group of archosauromorphs. This paper represents one of the last contributions of the Russian palaeornithologist Evgenii N. Kurochkin who passed away recently.
Buchwitz, M., C. Foth, I. Kogan, and S. Voigt. 2012 in press. On the use of osteoderm features in a phylogenetic approach on the internal relationships of the Chroniosuchia (Tetrapoda: Reptiliomorpha). Palaeontology. [DOI: 10.1111/j.1475-4983.2012.01137.x] [link]
Includes a graphic reconstruction of Madygenerpeton (drawing by Frederik Spindler).
Buchwitz, M. and S. Voigt. 2012 in press. The dorsal appendages of the Triassic reptile Longisquama insignis: reconsideration of a controversial integument type. Paläontologische Zeitschrift.
[DOI: 10.1007/s12542-012-0135-3] [Link]
More thorough description/ graphic documentation compared to Voigt et al.(2009) and considers some aspects of diapsid skin evolution.
[DOI: 10.1134/S0031030111060025] [link]
Description of a reptile fossil with skin preservation discovered in 2006. Comes form the same locality as Sharovipteryx and Longisquama. The authors interpret the specimen as a member of drepanosaurs, a Late Triassic group of archosauromorphs. This paper represents one of the last contributions of the Russian palaeornithologist Evgenii N. Kurochkin who passed away recently.
Buchwitz, M., C. Foth, I. Kogan, and S. Voigt. 2012 in press. On the use of osteoderm features in a phylogenetic approach on the internal relationships of the Chroniosuchia (Tetrapoda: Reptiliomorpha). Palaeontology. [DOI: 10.1111/j.1475-4983.2012.01137.x] [link]
Includes a graphic reconstruction of Madygenerpeton (drawing by Frederik Spindler).
Buchwitz, M. and S. Voigt. 2012 in press. The dorsal appendages of the Triassic reptile Longisquama insignis: reconsideration of a controversial integument type. Paläontologische Zeitschrift.
[DOI: 10.1007/s12542-012-0135-3] [Link]
More thorough description/ graphic documentation compared to Voigt et al.(2009) and considers some aspects of diapsid skin evolution.
Samstag, 10. September 2011
Madygen freshwater sharks made the JVP front page
Fischer, J., S. Voigt, J. W. Schneider, M. Buchwitz & S. Voigt (2011): A selachian freshwater fauna from the Triassic of Kyrgyzstan and its implication for Mesozoic shark nurseries. Journal of Vertebrate Paleontology 31: 937- 953. [Abstract]
Aha: Egg capsules and microvertebrate fossils can be a worthwile study object after all. (Event though Jan Fischer, my fellow grad student at the Geological Institute in Freiberg, had an interview with a critical local newsreporter who doubted that anybody could ever be interested in something like that.)
Jan and colleagues describe chondrichthyan egg capsule fossils from the Madygen Formation and refer them to Palaeoxyris, a capsule type usually assigned to hybodont sharks, and Fayolia, probably produced by xenacanth sharks. These fossils are accompagnied by nearby finds teeth of hybodont shark teeth - most of them are tiny and probably belonged to juveniles of the newly erected species Lonchidion ferganensis.
Oxygen isotope analysis of the teeth and their comparison to hybodont teeth from other localities yields a clear freshwater signal for the Madygen samples, indicating that the shark offspring indeed inhabited a freshwater habitat.
Facial analysis of the sedimentary succession of the Madygen Formation demonstrates the presence of wide-spread shallow and vegetated shore areas during the Middle Triassic which could have functioned as a shark nursery, i.e. a separate and ecologically distinct habitat for juveniles which was not invaded by adult sharks of the same species.
Aha: Egg capsules and microvertebrate fossils can be a worthwile study object after all. (Event though Jan Fischer, my fellow grad student at the Geological Institute in Freiberg, had an interview with a critical local newsreporter who doubted that anybody could ever be interested in something like that.)
Jan and colleagues describe chondrichthyan egg capsule fossils from the Madygen Formation and refer them to Palaeoxyris, a capsule type usually assigned to hybodont sharks, and Fayolia, probably produced by xenacanth sharks. These fossils are accompagnied by nearby finds teeth of hybodont shark teeth - most of them are tiny and probably belonged to juveniles of the newly erected species Lonchidion ferganensis.
Oxygen isotope analysis of the teeth and their comparison to hybodont teeth from other localities yields a clear freshwater signal for the Madygen samples, indicating that the shark offspring indeed inhabited a freshwater habitat.
Facial analysis of the sedimentary succession of the Madygen Formation demonstrates the presence of wide-spread shallow and vegetated shore areas during the Middle Triassic which could have functioned as a shark nursery, i.e. a separate and ecologically distinct habitat for juveniles which was not invaded by adult sharks of the same species.
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