Echinorhinus pfauntschi
| Echinorhinus pfauntschi | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Temporal occurrence | ||||||||||||
| Lower Miocene | ||||||||||||
| 18.3 to 17 million years | ||||||||||||
| Locations | ||||||||||||
| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Echinorhinus pfauntschi | ||||||||||||
| Arrow , 1983 |
Echinorhinus pfauntschi is an extinct nail shark , which is onlyknownfrom today's Upper Austria for its fossilized teeth. He lived in the Lower Miocene ( Ottnangien ) about 20 million years ago.
features
Echinorhinus pfauntschi is only known from the findings of teeth. These are very strong compared to those of other species of the genus. The main tip is high and slender and can be more or less inclined towards the thistle and reach the distal edge of the crown. The medial crown margin is very low and not bulging at the tip. He has no or only short and strong secondary point. Especially in the transition area between the main apex and the medial crown base, the crown margin is strongly notched mesially. The labial and lingual surfaces often have strong enamel folds that run from the tip to the tooth base. There are numerous large foramina on both the labial and lingual surfaces.
The tooth root is comparatively low. The tips of younger sharks differ from those of adult sharks (ontogenetic heterodontics ) in the complete absence of secondary tips; they are comparatively short and tall. The skin teeth (dermal denticles) are relatively small and can be fused together.
Locations
The type material for the description of Echinorhinus pfauntschi comes from a marl pit in Höbmannsbach in Upper Austria . Both the holotype and the two paratypes in the first regression horizon were found in the hanging wall of the marl facies of the Ottnanger Schliers , which lies in the basin facies of the Taufkirchen Bay. Further finds come from the transgression horizon and the marl facies of the Haller Schliere ( Eggenburgien ) in the lying area of the Atzbacher Sande as well as from Offenhausen and Kletzenmarkt .
Paleoecology
Echinorhinus pfauntschi was associated with numerous other rays and sharks and probably lived as an archibenthic species. Many of the known species are adapted to subtropical climatic conditions, especially the genera Mobula and Gymnura indicate high water temperatures. The other types of accompaniment include a. Chlamydoselache bracheri , Paraheptranchias repens and species of the genera Deania , Centrophorus , Centroscymnus , Centroselachus and Etmopterus .
Systematics
Echinorhinus pfauntschi was named after the Bavarian fossil collector Arnold Pfauntsch by its first scientific descriptor, Pfeil.
The weakly developed medial and distal secondary peaks and the slender, relatively high main point are described as special features of the species. This characteristic tooth shape distinguishes E. pfauntschi from all known species of the genus as well as from Paraechinorhinus riepli .
As a sister species diagnosed arrow occurring in the same sediment type Echinorhinus schoenfeldi . Further closer relationships are assumed with Echinorhinus pollerspoecki and Echinorhinus richiardii , which is regarded as a sister species of the species Echinorhinus brucus , which is still alive today .
supporting documents
- ↑ a b c d e Friedrich H. Pfeil: Dental morphological investigations on recent and fossil sharks of the orders Chlamydoselachiformes and Echinorhiniformes. Palaeo Ichthyologica 1, 1983: pp. 140-153.
literature
- Friedrich H. Pfeil: Dental morphological investigations on recent and fossil sharks of the orders Chlamydoselachiformes and Echinorhiniformes. Palaeo Ichthyologica 1, 1983: pp. 140-153.