Eucritta
| Eucritta | ||||||||||||
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Eucritta melanolimnetes (artistic reconstruction of life) |
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| Temporal occurrence | ||||||||||||
| Visa | ||||||||||||
| 345.3 to 328.3 million years | ||||||||||||
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| Scientific name | ||||||||||||
| Eucritta | ||||||||||||
| Clack , 1998 | ||||||||||||
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Eucritta is an extinct genus of the Baphetidae with only one species described. It lived in the Viséum , a stage of the early Carboniferous , 345.3 to 328.3 million years ago and is one of the earliest representatives of the terrestrial vertebrates. The Baphetidae are the first fossil terrestrial vertebrates ever to be found in strata of the Carboniferous; Eucritta represents the most basic genus within this group and is accordingly one of the most original known genera of terrestrial vertebrates.
The species Eucritta melanolimnetes was scientifically described in 1998 and named after the horror film Der Schreck vom Amazonas (English original title: Creature from the Black Lagoon ) from 1954.
features
Eucritta melanolimnetes has been described on the basis of an almost complete skeleton of the species. In addition to this holotype (UMZC (University Museum of Zoology, Cambridge) T1347a and b), several other skeletal parts of four individuals were available to the first person describing it.
The animals reached a body length of about 25 centimeters. The head length varies between 30 and 90 millimeters in the individuals described. In two individuals, in addition to the skull, there is also material from the postcranial skeleton . The cranial roof of this species is very similar to the Temnospondyle Balanerpeton from the same period. Like this one, Eucritta has a short snout, large eye sockets, noticeable notches behind the eyes and a very primitive pattern of the skull bones with direct contact between the supratemporal and the postparietal . There are differences in the structure of the palate , which is closed in Eucritta , as well as the position of the skull windows and the shape and position of individual other skull bones. The largest specimen has an indentation in the eye socket, which exists in a much more pronounced form as a feature of the Baphetidae.
The postcranial skeleton was only slightly ossified. It corresponds in numerous characteristics to other basal terrestrial vertebrates such as Acanthostega , the Anthracosauria and the Lepospondyli . Important features are a diamond-shaped bone between the clavicles (interclavicle) and an iliac bone with a dorsal leaf and a posterior process. The abdominal ribs (gastralia) are elongated.
Eucritta accordingly has a mosaic of features that are similar to those of the Temnospondyli and the Anthracosauria . The former mainly include the wide notches behind the eyes, the latter the closed palate and features of the pelvic girdle .
Location
The location of the fossils of Eucritta melanolimnetes comes from the Viséum of Scotland . It belongs to the East Kirkton Quarry in Bathgate in West Lothian, near Edinburgh . There the find comes from Unit 82, which is characterized by black slate .
Unit 82 is one of the earliest known sites that is clearly terrestrial. It was likely a habitat on a shallow lake that was hydrothermally active. The lake's water was likely poisonous to most living things, but its shores were rich in flora and fauna. In addition to Eucritta , numerous other important fossils from the early Carboniferous come from this site. So here with Balanerpeton woodi the oldest known representative of the Temnospondyli and with Eldeceeon rolfei and Silvanerpeton miripedes the two oldest Anthracosauria were found. Also westlothiana lizziae that the oldest amniotes heard and representatives of the Aïstopoda belonging to genus Ophiderpeton were discovered here.
In addition to these vertebrates, the site is home to fossils of former land-living arthropods such as land-living sea scorpions (Eurypterida), scorpions , centipedes and harvestmen .
Systematics and nomenclature
Eucritta melanolimnetes was scientifically described in 1998 by the British paleontologist Jennifer Clack in the journal Nature , a second, more detailed description was given in 2001 in the journal Transactions / Royal Society of Edinburgh. Earth Sciences . She assigned the fossil to the monotypical genus Eucritta , which she placed in the Baphetidae.
Eucritta melanolimnetes was named after the horror film Der Schreck vom Amazonas ( Creature from the Black Lagoon ) by director Jack Arnold from 1954. The generic name Eucritta is made up of the Greek word eu for “real” and the word critta from the American colloquial language for “creature” ( critter ). The species name is a combination of the two ancient Greek words melano for "black" and limnetes for "life in a pond or swamp", combined the name means "true creature from the black lagoon" ").
supporting documents
- ↑ a b c d e f J.A. Clack: A new Early Carboniferous tetrapod with a mélange of crown group characters. Nature 394, 1998: pp. 66-69.
- ↑ a b Eucritta in the Tree of Life project.
- ↑ JA Clack: Eucritta melanolimnetes from the Early Carboniferous of Scotland, a stem tetrapod showing a mosaic of characteristics. Transactions / Royal Society of Edinburgh. Earth Sciences 92, 2001; Pp. 75-95.
literature
- JA Clack: A new Early Carboniferous tetrapod with a mélange of crown group characters. Nature 394, 1998: pp. 66-69.
- JA Clack: Eucritta melanolimnetes from the Early Carboniferous of Scotland, a stem tetrapod showing a mosaic of characteristics. Transactions / Royal Society of Edinburgh. Earth Sciences 92, 2001; Pp. 75-95.
- M. Ruta, MI Coates, DLJ Quicke: Early tetrapod relationships revisited. Biological Reviews 78, 2003: pp. 251-345.
Web links
- Eucritta in the Tree of Life project.