Apateon
| Apateon | ||||||||||
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Fossils of Apateon pedestris , in the Senckenberg Naturmuseum in Frankfurt am Main |
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| Temporal occurrence | ||||||||||
| Gzhelium to Sakmarium ( Upper Carboniferous to Lower Permian ) | ||||||||||
| 303.7 to 290.1 million years | ||||||||||
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| Systematics | ||||||||||
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| Scientific name | ||||||||||
| Apateon | ||||||||||
| Meyer , 1844 | ||||||||||
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Apateon is a species-rich genus of the Temnospondyles , which is found in the Upper Carboniferous and Lower Permian of Central Europe. In many sub-Permian sites, these branchiosaurids are the most common vertebrates.
description
Apateon was a 5–12 cm long, pig-like temnospondyle with a weakly ossified skeleton and a broad, short skull. Despite the similarity to today's salamanders, the skull was closed. However, the eye openings were huge and the bones surrounding them were greatly reduced (prefrontals, postfrontals, postorbital, jugals). There were large openings on the palate, the teeth were small and pin-shaped. In the spine, mostly only the neural arches were ossified, and the carpal and tarsus remained cartilaginous. From preserved skin shadows we know that the tail was flattened on the sides and very long. The body was covered all around with rounded bones.
Fossil Conservation
In the fine-grained find layers of Apateon , remnants of the outer gills were often preserved, which, like salamander larvae, were mostly tufted. Skin shadows are also often preserved, sometimes even with color patterns.
Way of life
Most branchiosaurids lived their entire lives in standing or flowing water, where they filtered microorganisms with their differentiated gill endicles. Histological findings show that some species of Apateon became sexually mature in the larval state ( neoteny ). This had long been suspected because of their numerous larval features. Converted specimens have so far only been described of a single species, Apateon gracilis from Niederhäslich. This finding made it possible to reconstruct the metamorphosis of these almost 300 million year old temnospondyles.
Historical
In 1844, Hermann von Meyer named a tiny, inconspicuous skeleton as Apateon pedestris (Greek for “swindlers with legs”) - at that time, vertebrates from such ancient layers were not known. Antonin Fritsch and Hermann Credner only reported massive finds of branchiosaurids from Nýřany (Bohemia) and Niederhäslich (Saxony) in the 1880s . Branchiosaurids have long been interpreted as larvae of larger Temnospondyles, such as. B. Sclerocephalus , Onchiodon or Eryops . Only Jürgen Boy (University of Mainz) was able to prove that it is a separate group of larval-looking temnospondyles that were more closely related to dissorophoids than eryopiformes.
literature
- Hermann von Meyer, 1844: Letter addressed to Prof. Bronn. New yearbook for geognosy, geology and petrefacts customer 1844: 329-340.
- Hermann von Meyer, 1848: Apateon pedestris from the hard coal formation of Münsterappel. - Palaeontographica 1: 153-154.
- Jürgen Boy, 1972: The branchiosaurs (Amphibia) of the Saar-Palatinate Rotliegend (Perm, SW Germany). Treatises of the Hessian State Office for Soil Research 65: 1-137.
- Jürgen Boy, 1987: Studies about the Branchiosauridae (Amphibia: Temnospondyli; Ober-Karbon-Unter-Perm) 2. Systematic overview. New Yearbook of Geology and Paleontology Papers 174: 75-104.
- Rainer Schoch, 1992: Comparative ontogeny of Early Permian branchiosaurid amphibians from Southwestern Germany. Developmental stages. Palaeontographica A 222: 43-83.
- Ralf Werneburg, 1991: The branchiosaurs from the Unterrotliegend of the Döhlen basin near Dresden. Publications of the Natural History Museum Schleusingen 6: 75-99.
- Rainer Schoch and Andrew Milner, 2014: Temnospondyli. In: Sues, HD (Ed.): Encyclopedia of Paleoherpetology, Volume 3A2. Arrow: Munich.
Individual evidence
- ↑ Schoch, RR & Milner, AR (2008): The intrarelationships and evolutionary history of the temnospondyl family Branchiosauridae. Journal of Systematic Palaeontology, 6: 409-431.
- ↑ Werneburg, R. (2002): Apateon dracyiensis - an early pioneering form of branchiosaurs from the European Rotliegend. Part 2: Paleoecology. - Publications of the Natural History Museum Schleusingen 17: 17-32.
- ↑ Boy, JA (1972): The Branchiosaurier (Amphibia) of the Saar-Palatinate Rotliegend (Perm, SW Germany). Treatises of the Hessian State Office for Soil Research 65: 1-137.
- ^ Witzmann, F. (2004): The external gills of Palaeozoic amphibians. New Yearbook of Geology and Apalaeontology Papers 232: 375–401
- ^ Werneburg, R. (2007): Timeless design: colored pattern of skin in Early Permian branchiosaurid (Temnospondyli: Dissorophoidea). Journal of Vertebrate Paleontology 27: 1047-1050.
- ↑ Boy, JA (1987): Studies uber die Branchiosauridae (Amphibia: Temnospondyli; Ober-Karbon-Unter-Perm) 2. Systematic review. New Yearbook of Geology and Paleontology Papers 174: 75-104.
- ^ Sanchez, S., A. de Ricqles, RR Schoch & JS Steyer (2010): Developmental plasticity of limb bone microstructural organization in Apateon: histological evidence of paedomorphic conditions in branchiosaurs. Evolution and Development 12: 315-328.
- ↑ Boy, JA (1971): On the problem of branchiosaurs (Amphibia, Karbon-Perm). Paleontological Journal 45: 107-119.
- ↑ Werneburg, R. (1991): The branchiosaurs from the Unterrotliegend of the Döhlen basin near Dresden. Publications of the Natural History Museum Schleusingen 6: 75-99.
- ↑ Schoch, RR & NB Froebisch (2006): Metamorphosis and neoteny: alternative developmental pathways in an extinct amhibian clade. Evolution 60: 1467-1475.
- ^ Romer, AS (1939): Notes on branchiosaurs. American Journal of Science 237: 748-761.
- ↑ Boy, JA (1972): The Branchiosaurier (Amphibia) of the Saar-Palatinate Rotliegend (Perm, SW Germany). Treatises of the Hessian State Office for Soil Research 65: 1-137.